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  • Sleipner: The ongoing challenge to determine the thickness of a thin CO2 layer
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2018-01-09
    James C. White, Gareth Williams, Andy Chadwick, Anne-Kari Furre, Anders Kiær

    Sleipner is the world’s longest-running CO2 storage project. Since injection commenced in 1996 almost 1 million tonnes per year have been injected with more than 16 million tonnes successfully stored by 2016. A comprehensive programme of time-lapse 3D seismic monitoring has been carried out, providing unrivalled imaging of the CO2 plume as it has developed and migrated in the storage reservoir. The plume has a tiered structure comprising a number of thin layers of CO2 of the order of a few metres thick. Determination of accurate layer morphology is key to understanding details of fluid flow processes in the plume which is necessary to demonstrate future storage security. Migration of the topmost layer of CO2, trapped directly beneath the reservoir topseal, determines the longer-term storage performance at Sleipner and here we focus on mapping its travel-time (temporal) thickness. Our primary approach is to use spectral analysis to determine tuning frequencies across the layer and from these to derive temporal thickness. These range from zero at the layer edges to around 16 ms in the central parts of the layer and correlate closely with the base topseal topography. Uniquely, results are then compared with those from other published approaches including amplitude analysis, temporal shifts and direct measurement of temporal spacing on the latest high-resolution seismic data. It is clear that the spectral methods provide robust determination of temporal thickness well below the tuning thickness, and, taken in suitable combination with the various other methods, can provide reliable determination of temporal thickness across the range from close to zero to well above the tuning thickness where explicit layer resolution is obtained. Application of an appropriate layer velocity allows true layer thicknesses to be determined and layer volumetrics to be estimated.

    更新日期:2018-01-10
  • Assessment of two-phase flow on the chemical alteration and sealing of leakage pathways in cemented wellbores
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2018-01-08
    Jaisree Iyer, Stuart D.C. Walsh, Yue Hao, Susan A. Carroll
    更新日期:2018-01-09
  • CO2 capture efficiency and heat duty of solid acid catalyst-aided CO2 desorption using blends of primary-tertiary amines
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2018-01-02
    Wayuta Srisang, Fatemeh Pouryousefi, Priscilla Anima Osei, Benjamin Decardi-Nelson, Ananda Akachuku, Paitoon Tontiwachwuthikul, Raphael Idem

    This study evaluated improvements in the CO2 capture process in terms of cyclic capacity, absorption efficiency and heat duty caused by using a primary amine (5 M MEA) blended with a tertiary amine (2 M MDEA or 1.25 M DEAB) and a catalyst-aided desorber loaded with two different solid acid catalysts (γ-Al2O3 or HZSM-5) in a bench scale full cycle CO2 capture plant. The absorber and desorber were stainless steel pipes with inside diameter of 0.05 m and height of 1.50 m. The desorber was loaded with varying amounts of solid acid catalyst at an average bed temperature of 85 °C. The two mixed amine solvents tested, were compared with 5 M MEA each with a circulation rate of 0.06 L/min. Simulated flue gas, 15% CO2 in N2, was used at a total flow rate of 15 SLPM. The results showed that in 5 M MEA system, cyclic capacity and absorption efficiency increased while heat duty decreased when the catalyst amount was increased. In the case of mixed primary and tertiary amines, catalysts contribute to slight improvements. The increase in absorption efficiency was found to be in the order of 5 M MEA: γ-Al2O3 < 5 M MEA: HZSM–5 < 5 M MEA: 2 M MDEA: γ-Al2O3 < 5 M MEA: 2 M MDEA: HZSM–5 < 5 M MEA: 1.25 M DEAB: γ-Al2O3 < 5 M MEA: 1.25 M DEAB: HZSM-5. The relative reduction in heat duty of the system was found to be in the order of 5 M MEA: 1.25 M DEAB: HZSM–5 < 5 M MEA: 2 M MDEA: HZSM–5 < 5 M MEA: 1.25 M DEAB: γ-Al2O3 < 5 M MEA: 2 M MDEA: γ-Al2O3 < 5 M MEA: HZSM-5 < 5 M MEA: γ-Al2O3.

    更新日期:2018-01-03
  • Experimental investigation of CO2 removal from N2 by metal oxide nanofluids in a hollow fiber membrane contactor
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2018-01-02
    Hamed Mohammaddoost, Ahmad Azari, Meisam Ansarpour, Shahriar Osfouri

    The elimination of carbon dioxide (CO2) using water-based nanofluids (NFs) in a hollow fiber membrane contactor (HFMC) using polypropylene (PP) membrane was experimented. Gas flows in the shell, while NF flows in the fibers. Metal oxide nanoparticles (NPs) such as aluminum oxide (Al2O3), titanium dioxide (TiO2) and silica (SiO2) in the concentrations of 0.05, 0.1 and 0.2 wt % were used in the experiments. Some factors such as gas flow rates, NPs type, NF temperature, NP concentration, as well as the effect of particle size on the separation were investigated. The results clearly show that the highest flux of CO2 occurred for 0.2 wt % concentration of Al2O3 NFs. Mass transfer flux enhancement (MTFE) was defined as the relative mass transfer flux (MTF) of CO2 in the NFs with respect to the MTF of CO2 in the de-ionized water as the base fluid. MTFE changed from 1.29 to 2.25 for the Al2O3 NFs. Among all the results, the best result was obtained for Al2O3 (40 nm) at 1.6 Lit/min liquid flow rate, 25 °C liquid temperature, 5 Lit/min gas flow rate and 40% inlet CO2 concentration which is 98.9% CO2 removal. Finally, a new correlation was developed for the Sherwood (Sh) number for the CO2 mass transfer in the NFs flowing in the fibers. Sh number was developed based on the NFs Reynolds (Re) number, NPs Reynolds (Renp) number, Schmidt (Sc) number, and NPs volume fraction with an average relative error percent (REP) of 1.6% and R2 of 0.99.

    更新日期:2018-01-03
  • Quantifying the effects of depositional environment on deep saline formation co2 storage efficiency and rate
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 
    Nicholas W. Bosshart, Nicholas A. Azzolina, Scott C. Ayash, Wesley D. Peck, Charles D. Gorecki, Jun Ge, Tao Jiang, Neil W. Dotzenrod

    In an effort to reduce carbon dioxide (CO2) emissions from large stationary sources, carbon capture and storage (CCS) is being investigated as one approach in a portfolio of greenhouse gas (GHG) reduction strategies. This work assesses CO2 storage rates and efficiency of saline formations classified by interpreted depositional environment at the regional scale over a 100-year time frame. The focus of this study was placed on developing results applicable to future commercial-scale CO2 storage operations in which an array of injection wells would be used to optimize storage in saline formations. The results of this work suggest future investigations of prospective storage resource in closed or semiclosed formations that may focus less heavily on interpretation of depositional processes. However, the results illustrate the relative importance of depositional environment, aquifer depth, structural geometry, and boundary conditions on the rate of CO2 storage in closed or semiclosed systems.

    更新日期:2017-12-31
  • Comparison of various configurations of the absorption-regeneration process using different solvents for the post-combustion CO2 capture applied to cement plant flue gases
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-12-27
    Lionel Dubois, Diane Thomas

    Carbon Capture Utilization or Storage (CCUS) has gained widespread attention as an option for reducing CO2 emissions from power plants but specific developments are still needed for the application to cement plants. More precisely, the post-combustion CO2 capture process by absorption-regeneration is the more mature technology but its cost reduction is still necessary. The present study is focusing on Aspen Hysys™ simulations of different CO2 capture process configurations (namely “Rich Solvent Recycle” (RSR), “Solvent Split Flow” (SSF), “Lean/Rich Vapor Compression” (L/RVC)) applied to the flue gas coming from the Norcem Brevik cement plant (taken as case study) and using three different solvents, namely: monoethanolamine (MEA), piperazine (PZ) and piperazine-methyldiethanolamine (MDEA) blend. For each configuration and solvent, different parametric studies were carried out in order to identify the operating conditions ((L/G)vol., split fraction, flash pressure variation, etc.) minimizing the solvent regeneration energy. Total equivalent thermodynamic works and utilities costs were also analyzed. It was shown that the configurations studied allow regeneration energy savings in the range 4–18%, LVC and RVC leading to the higher ones. As perspectives, other configurations and combination of configurations will be considered in order to further reduce the energy consumption of the process.

    更新日期:2017-12-31
  • Influence of formaldehyde on N-nitrosopiperazine formation from nitrite and piperazine in CO2 capture
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-12-27
    Yan Zhou, Yiheng Rao, Tielin Wang, Klaus-J. Jens

    Piperazine (PZ) based amine blends are promising solvents for post-combustion CO2 capture, but PZ can form potential carcinogenic nitrosamines from nitrite. In this work, the kinetics of the reaction between nitrite and PZ to form N-nitrosopiperazine (MNPZ) was determined in 0.1–0.5 mol L−1 PZ in the presence of 17–170 mmol L−1 formaldehyde at 60–135 °C. The nitrosation of PZ can be catalyzed by formaldehyde, a primary degradation product of PZ. And the reaction involving nitrite and PZ is first order in nitrite, formaldehyde, and hydronium ion. A kinetic model was established, and the activation energy is 33.6 ± 1.8 kJ mol−1 with a rate constant of 2.3 × 103 ± 0.4 × 103 L2 mol−2 s−1 at 100 °C. The kinetics will be helpful to develop strategies to reduce nitrosamine formation and accumulation in PZ based CO2 capture systems.

    更新日期:2017-12-31
  • Quantifying CO2 storage efficiency factors in hydrocarbon reservoirs: A detailed look at CO2 enhanced oil recovery
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-12-29
    Wesley D. Peck, Nicholas A. Azzolina, Jun Ge, Nicholas W. Bosshart, Matthew E. Burton-Kelly, Charles D. Gorecki, Andrew J. Gorz, Scott C. Ayash, David V. Nakles, L. Stephen Melzer

    Carbon dioxide (CO2) enhanced oil recovery (EOR) will likely be the primary means of geologic CO2 storage during the early stages of commercial-scale carbon capture and storage (CCS) because of the inherent economic incentives as well as the abundant experience and demonstrated success in the United States, where CO2 EOR has been employed since 1974. The work presented here estimates CO2 storage efficiency factors in CO2 EOR operations using a unique industry database of CO2 EOR sites and 12 different reservoir simulation models. The simulation models encompass fluvial clastic and shallow shelf carbonate depositional environments for reservoir depths of 1219 and 2438 m (4000 and 8000 feet) and 7.6-, 20-, and 64-m (25-, 66-, and 209-foot)-thick pay zones. A novel statistical modeling technique incorporating the Michaelis–Menten function is used to generate empirical percentile estimates of CO2 storage efficiency factors. West Texas San Andres dolomite water alternating gas (WAG) CO2 flood performance data were used to derive P10, P50, and P90 CO2 storage efficiency factors of 0.76, 1.28, and 1.74 Mscf/STB (stock tank barrel) of original oil in place. Median CO2 storage efficiency factors from continuous CO2 injection following conventional waterflood varied from 15% to 61% and 8% to 40% for fluvial clastic and shallow shelf carbonate simulation models, respectively, while those from WAG injection varied from 14% to 42% and 8% to 31%, respectively. Variation in the CO2 storage efficiency factors was largely attributable to reservoir depth (a surrogate for reservoir pressure and temperature) and lithology (clastic versus carbonate). The results of this work provide practical information that can be used to quantify CO2 storage resource estimates in oil reservoirs during CO2 EOR operations (as opposed to storage following depletion) and the uncertainty associated with those estimates.

    更新日期:2017-12-31
  • Corrigendum to “The latest monitoring progress for Shenhua CO2 storage project in China” [International Journal of Greenhouse Gas Control, 60 (2017) 199–206]
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-12-27
    Zhao Xinglei, Ma Rui, Zhang Feng, Zhong Zhencheng, Wang Baodeng, Wang Yongsheng, Li Yonglong, Weng Li
    更新日期:2017-12-31
  • Chemical looping with air separation (CLAS) in a moving bed reactor with CuO/ZrO2 oxygen carriers
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-12-21
    Young Ku, Hsuan-Chih Wu, Chia-Wei Chang, Shr-Han Shiu

    Zirconia supported CuO oxygen carriers were prepared for carrying out chemical looping with oxygen uncoupling (CLOU) and chemical looping with air separation (CLAS) operation in a thermogravimetric analyzer (TGA), a fixed bed reactor and a moving bed reactor (MBR). In this study, graphite used as solid fuel for CLOU with CuO/ZrO2 oxygen carriers was also explored in a fixed bed reactor. 40 wt.% CuO/ZrO2 particles sintered at 1000 °C revealed reasonable reactivity without noticeable agglomeration as observed. For fixed bed operation, time required for graphite combustion with CuO/ZrO2 was decreased for experiments conducted at higher reaction temperatures. For experiments carried out in the moving bed reactor, the oxygen concentration and oxygen molar flow rate in the outlet stream can be adjusted by varying operating temperatures, CuO/ZrO2 flow rate, and carrier gas (N2) flow rate. Therefore, moving bed reactors are technically feasible to serve as fuel reactor for chemical looping with air separation.

    更新日期:2017-12-22
  • 更新日期:2017-12-15
  • Potential for using municipal solid waste as a resource for bioenergy with carbon capture and storage (BECCS)
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-09
    Nasim Pour, Paul A. Webley, Peter J. Cook

    Bioenergy with Carbon Capture and Storage (BECCS) is a carbon removal technology that offers permanent net removal of carbon dioxide (CO2) from the atmosphere. One of the significant bioenergy resources is organic waste collected from municipal solid waste (MSW). The goal of this study was to provide an estimate of the global potential for using municipal solid waste as a resource for bioenergy with carbon capture and storage (BECCS) and to compare the feasibility of two specific BECCS options: municipal solid waste incineration with carbon capture and storage (MSW-CCS), and landfill gas combusted in a gas turbine with carbon capture and storage (LFG-CCS). To assess the feasibility of MSW-based BECCS options, techno-economic and environmental impact assessments were conducted. In the case of a “business-as-usual” scenario with no emission policy in effect, the levelised cost of electricity production from both BECCS options is higher than a coal power plant with CCS. However, these BECCS systems offer a lower cost of avoided CO2. Introducing renewable energy certificates or negative emission refund schemes to BECCS has a significant impact on the economic viability of these technologies in coal-dominant power markets. Environmental impact assessment shows that around 0.7 kg CO2-eq is removed for each kg of wet MSW incinerated, for the MSW-CCS scenario. This translates to approximately negative 2.8 billion tonnes CO2 if all the available 4 billion tonnes MSW generated per year by 2100 is utilised in a MSW-CCS system. The net GHG emission of the LFG-CCS system with an average LFG collection rate of 75% was 0.56 kg CO2-eq. Challenges include the dispersed nature of MSW resources and the lack of economic support schemes, such as commonly apply to solar and wind. Nonetheless, MSW-based BECCS technologies have significant potential for abating and in some cases removing considerable amounts of the greenhouse gases from the atmosphere, thereby contributing significantly to the COP21 emission reduction targets.

    更新日期:2017-12-14
  • Understanding key elements in establishing a social license for CCS: An empirical approach
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-10
    Clair Gough, Rebecca Cunningham, Sarah Mander

    This paper presents results of empirical research with the broad aim of exploring societal responses to CO2 storage, framed around the concept of social license to operate (SLO). We describe a mixed method approach incorporating stakeholder interviews and focus groups deployed in two case study locations in the UK. The approach helps us to build up an understanding of the social context in which Carbon Capture and Storage (CCS) will be introduced, in terms of the specific local conditions and with reference to the influence of local experiences of other technologies (such as hydraulic fracturing (fracking), for example). This understanding is then used to guide further empirical research, from which we assess the extent to which an SLO for CCS is emerging. Results show that perceptions of trust and confidence in key institutions to safely manage projects are highly dependent not just on the track record of the organisations but are strongly influenced by past experiences with different technologies. While the indications for achieving an SLO for CCS are currently positive, consolidating and maintaining that support depends on the evolving social, industrial and political landscape.

    更新日期:2017-12-14
  • Linking the local vertical variability of permeability and porosity to newly-interpreted lithofacies in the lower Mt. Simon CO2 reservoir
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-10
    Robert W. Ritzi, Ritu Ghose, Michael Bottomley, Arnold J.H. Reesink, Jim Best, Jared T. Freiburg, Nathan D. Webb

    A full understanding of the subsurface processes relevant to CO2 geo-sequestration, including CO2 movement and trapping, requires establishing basic relationships between the sedimentary architecture in CO2 reservoirs and the associated variations in petrophysical attributes that can affect plume dynamics and residual CO2 trapping. In this context, the variance and covariance of petrophysical attributes of the lower Mt. Simon Sandstone reservoir (Illinois, USA) are quantitatively decomposed according to sedimentary textures and structures that vary among sedimentary facies. Building on Ritzi et al. (2016), the sedimentary facies of the lower Mt. Simon are re-classified with new interpretations of sedimentary structures. A newly-revised methodology is used in which factor interactions are formally quantified and the magnitude of their contribution to the variance is compared to the main-factor effects. The decomposition results show the main-factor effects contributing to the variance of permeability and porosity are the differences in grain-size and the presence or absence of bleaching textures. The differences in permeability or porosity among the newly defined sedimentary structures make a relatively small contribution to the sample variance, and the 2-way and 3-way factor interactions are negligible. Permeability and porosity increase with coarser grain size, independent of the presence or absence of bleaching and independent of sedimentary structure. The presence of bleaching textures reduces permeability and porosity independent of the grain size or sedimentary structure. The general approach and these specific results aid in developing parsimonious reservoir simulation models.

    更新日期:2017-12-14
  • Non-invasive monitoring of CO2 concentration in aqueous diethanolamine (DEA), methyldiethanolamine (MDEA) and their blends in high CO2 loading region using Raman spectroscopy and partial least square regression (PLSR)
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-12
    Muhammad Zubair Shahid, Abdulhalim Shah Maulud, M.A. Bustam

    Chemical absorption using amines is a suitable method to separate CO2 from CO2 rich natural gas stream. An instantaneous monitoring of CO2 concentration in amine solvent is essential for an efficient chemical absorption process. A spectroscopic technique such as Raman spectroscopy along with multivariate modeling is considered as a robust and fast analytical method. It has been applied to monitor CO2 concentration in a chemical absorption process. However, these studies are limited to low CO2 loadings (<0.5 molCO2/molamine) and cannot be extrapolated to high CO2 loading conditions. The evaluation of Raman method at high CO2 loading is essential for the application at high pressure gas streams. In the present study, Raman spectroscopy is non-invasively applied to monitor CO2 concentration in aqueous amines (DEA, MDEA, and their blends) over a wide range of CO2 loadings (0.04–1.3 molCO2/molamine). The partial least square regression (PLSR) calibration models are developed and validated accordingly. The prediction accuracy is reported using determination coefficient (R2) and root mean square error (RMSE). The average validation R2V and RMSEV for all the studied systems are calculated as 0.94 and 0.064 molCO2/molamine respectively. These values show that Raman spectroscopy with PLSR is a promising technique to monitor CO2 concentration for a wide range of CO2 loading. The improvement in CO2 monitoring is expected to enhance the process efficiency of natural gas processing plants.

    更新日期:2017-12-14
  • Reduced-order modeling of CO2 storage operations
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-14
    Zhaoyang Larry Jin, Louis J. Durlofsky

    A POD-TPWL reduced-order modeling framework is developed to simulate and optimize the injection stage of CO2 storage operations. The method combines trajectory piecewise linearization (TPWL), where solutions with new sets of well controls are constructed based on linearization around previously simulated (training) solutions, and projection into a low-dimensional subspace using proper orthogonal decomposition (POD). The resulting representation is low-dimensional and linear, in contrast to the original nonlinear full-order flow simulations. Several new POD-TPWL treatments are introduced and demonstrated. These include the use of multiple derivatives, meaning that the linearizations are performed around different training solutions at different time steps, and the use of rate-controlled (rather than pressure-controlled) injection wells. Two example cases are presented, and the ability of the POD-TPWL model to accurately capture wellbore pressure, when time-varying CO2 injection rates are prescribed, is demonstrated. It is also shown that, for these examples, the reduced-order models can provide accurate estimates of CO2 molar fraction at particular locations in the domain. The POD-TPWL model is then incorporated into a mesh adaptive direct search optimization framework where the objective is to minimize the amount of CO2 reaching a target layer at the end of the injection period. The POD-TPWL model is shown to be well suited for this purpose and to provide optimization results that are comparable to those obtained using full-order simulations. The preprocessing computations needed to construct the POD-TPWL models entail a (serial) time equivalent of about 6.7 full-order simulations, though the resulting runtime speedups, relative to full-order simulation, are about 100–150 for the cases considered.

    更新日期:2017-12-14
  • Influence of pKa on solvent performance of MAPA promoted tertiary amines
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-13
    Ida M. Bernhardsen, Iris R.T. Krokvik, Cristina Perinu, Diego D.D. Pinto, Klaus J. Jens, Hanna K. Knuutila

    In the present work, absorption and desorption performance of ten single tertiary amines and their blends with MAPA was studied using a screening apparatus. Absorption experiments were conducted at 40 °C and up to 9.5 kPa partial pressure of CO2, while desorption experiments were conducted at 80 °C and down to 1.0 kPa partial pressure of CO2. In addition, the pKa value of the studied amines was measured at 25 °C. The results indicated that the optimal pKa of the tertiary amines, giving the highest absorption capacity and cyclic capacity, was in the range of 9.48–10.13. At a higher pKa value, the cyclic capacity was decreased. Further, addition of MAPA to the tertiary amines influenced the absorption performance by increasing the absorption capacity for tertiary amines with low pKa (7.79–9.03) and decreasing the absorption capacity for tertiary amines with high pKa (9.48–10.42). Also, the CO2 absorption rate was significant enhanced by addition of MAPA.

    更新日期:2017-12-14
  • The impact of time-varying CO2 injection rate on large scale storage in the UK Bunter Sandstone
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-14
    Clea Kolster, Simeon Agada, Niall Mac Dowell, Samuel Krevor

    Carbon capture and storage (CCS) is expected to play a key role in meeting targets set by the Paris Agreement and for meeting legally binding greenhouse gas emissions targets set within the UK (Energy and Climate Change Committee, 2016). Energy systems models have been essential in identifying the importance of CCS but they neglect to impose constraints on the availability and use of geologic CO2 storage reservoirs. In this work we analyse reservoir performance sensitivities to varying CO2 storage demand for three sets of injection scenarios designed to encompass the UK's future low carbon energy market. We use the ECLIPSE reservoir simulator and a model of part of the Southern North Sea Bunter Sandstone saline aquifer. From a first set of injection scenarios we find that varying amplitude and frequency of injection on a multi-year basis has little effect on reservoir pressure response and plume migration. Injectivity varies with site location due to variations in depth and regional permeability. In a second set of injection scenarios, we show that with envisioned UK storage demand levels for a large coal fired power plant, it makes no difference to reservoir response whether all injection sites are deployed upfront or gradually as demand increases. Meanwhile, there may be an advantage to deploying infrastructure in deep sites first in order to meet higher demand later. However, deep-site deployment will incur higher upfront cost than shallow-site deployment. In a third set of injection scenarios, we show that starting injection at a high rate with ramping down, a low rate with ramping up or at a constant rate makes little difference to the overall injectivity of the reservoir. Therefore, such variability is not essential to represent CO2 storage in energy systems models resolving plume and pressure evolution over decadal timescales.

    更新日期:2017-12-14
  • The geochemical effects of O2 and SO2 as CO2 impurities on fluid-rock reactions in a CO2 storage reservoir
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-15
    Hong Phuc Vu, Jay R. Black, Ralf R. Haese

    Costs for CO2 capture could be reduced if CO2 gas impurities can be co-injected and do not adversely affect the long-term CO2 containment. This project, as a part of the Callide Oxyfuel Project, investigates the geochemical impacts of the CO2 impurities SO2 and O2 on mineral-fluid reactions in a siliciclastic reservoir. In a single-well push-pull field experiment CO2-saturated water with and without impurities was injected into the reservoir. The injection water was allowed to interact with minerals in the reservoir for three weeks, during which water was back-produced and sampled on three occasions. Four soluble tracers were added to the injection water to estimate the proportions of injection and formation water in the back-produced water. Redox state, speciation and reaction pathway modelling are used as part of the data interpretation. Once injected, SO2 (67 ppm vol/vol, initially as a dissolved impurity in CO2) was dissolved and oxidised, leading to sulphate formation. The alkalinity of the injection water counteracted any substantial decrease in pH, which would otherwise occur due to sulphuric acid formation, thus inhibiting additional mineral dissolution. After being injected, O2 (6150 ppm vol/vol, dissolved impurity in CO2) led to immediate oxidative dissolution of pyrite. Consequently, the SO42− concentration increased rapidly and dissolved iron is predicted to precipitate as hematite. Overall, the impact of CO2 impurities was minimal.

    更新日期:2017-12-14
  • Reservoir-condition pore-scale imaging of dolomite reaction with supercritical CO2 acidified brine: Effect of pore-structure on reaction rate using velocity distribution analysis
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-24
    Yousef Al-Khulaifi, Qingyang Lin, Martin J. Blunt, Branko Bijeljic

    To investigate the impact of rock heterogeneity and flowrate on reaction rates and dissolution dynamics, four millimetre-scale Silurian dolomite samples were pre-screened based on their physical heterogeneity, defined by the simulated velocity distributions characterising each flow field. Two pairs of cores with similar heterogeneity were flooded with supercritical carbon-dioxide (scCO2) saturated brine under reservoir conditions, 50 °C and 10 MPa, at a high (0.5 ml/min) and low (0.1 ml/min) flowrate. Changes to the pore structure brought about by dissolution were captured in situ using X-ray microtomography (micro-CT) imaging. Mass balance from effluent analysis showed a good agreement with calculations from imaging. Image calculated reaction rates (reff) were 5-38 times lower than the corresponding batch reaction rate under the same conditions of temperature and pressure but without mass transfer limitations. For both high (Péclet number = 2600-1200) and low (Péclet number = 420-300) flow rates, an impact of the initial rock heterogeneity was observed on both reaction rates and permeability-porosity relationships.

    更新日期:2017-12-14
  • Designing an optimum carbon capture and transportation network by integrating ethanol distilleries with fossil-fuel processing plants in Brazil
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-16
    Isabela S. Tagomori, Francielle M. Carvalho, Fabio T.F. da Silva, Paulo Roberto de C. Merschmann, Pedro R.R. Rochedo, Alexandre Szklo, Roberto Schaeffer

    Different long-term mitigation scenarios indicate carbon capture and storage associated with biomass (BECCS) might play a significant role in climate-change mitigation efforts, especially when it comes to long-term temperature stabilization. The ethanol fermentation process is considered as an early opportunity for BECCS deployment due to its low capture costs. Being a major ethanol producer, Brazil stands in a privileged position for the development of this technological option. However, previous scientific studies indicate several challenges for the deployment of a CO2 transportation network in the country, mostly as a result of the associated seasonality of the sugarcane industry and consequent idleness observed in the carbon transportation infrastructure. To address those issues, this study developed and applied a methodology to design an optimum carbon network considering an alternative concept: the incorporation of new CO2 emission sources aiming at guaranteeing adequate operational flows throughout the year, minimizing idleness and reducing transportation costs. Findings indicate that the incorporation of new CO2 emission sources reduces transportation costs. The inclusion of CO2 from both the cogeneration process and fossil sources results in an average levelized cost of transportation of 26 US$/tCO2 (54% lower than transportation costs in the baseline case). However, this reduction in transportation costs does not compensate for the increase in capture costs, resulting in higher levelized abatement costs for the whole system. Indeed, cases including cogeneration have reached a levelized abatement cost of approximately 125 US$/tCO2 (84% higher than in the baseline case). Nevertheless, by reducing transportation costs the strategy adopted in this study could facilitate the development of a carbon transportation network. Additionally, the integration of fossil-derived CO2 has proved beneficial to the system, allowing improvements in flow regularity and reducing idleness problems related to the seasonality of biogenic sources.

    更新日期:2017-12-14
  • Experimental evaluation of carbonated brine-limestone interactions under reservoir conditions-emphasis on the effect of core scale heterogeneities
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-21
    Mohamed Khather, Ali Saeedi, Reza Rezaee, Ryan R.P. Noble

    CO2 injection into deep geological structures is very often accompanied by chemical interactions between the host rock and injected fluids and/or the in-situ created solute (i.e. carbonated brine). In fact, the in-situ reactions are considered one way through which the injected CO2 may be trapped for perpetuity. Depending on the nature and mineralogy of the host rock formation, such reactions may eventually result in a degree of change in the petrophysical properties of the rock. Carbonate formations, due to the presence of highly reactive minerals in their composition, are expected to be more prone to such changes than their sandstone counterparts. This manuscript presents the results of an experimental study conducted to evaluate possible changes in the petrophysical properties of five heterogeneous limestone samples (calcite concentration >91 wt%). The study includes five reservoir condition core-flood experiments (i.e. one per each rock sample) complemented by other laboratory measurements/analyses including porosity-permeability measurements, X-ray CT (X-ray Computed Tomography) and SEM (Scanning Electron Microscopy) imaging. The results show a significant increase in the post-flood permeability of 80% of the samples caused by the dissolution and removal of carbonate minerals. The X-ray CT images reveal signs of significant mineral dissolution and establishment of flow paths through the initial larger pores in the samples leading, eventually, to the formation of wormhole features along the length of the samples. On the contrary, reduction in permeability is observed in one sample which was a relatively long (15.8 cm) composite sample consisting of two core segments placed one after the other in series. The other four samples were shorter with a nominal length of 6.4 cm. This reduction in permeability is observed predominantly in the outlet segment. This change is thought to have been primarily caused by possible migration of carbonate fines released by mineral dissolution in the inlet plug of the long composite core and to a lesser extent by the precipitation of minerals dissolved and transported from the inlet plug. This hypothesis finds further support in the pre- and post-flood dry weight measurements as well as a post-flood SEM image of the plug which reveals signs of fines migration and mineral precipitation. Slight reductions in the porosity and pore sizes are observed in most of the samples. This is likely to have been caused by the combined effect of fines migration, possible mineral precipitation and physical compaction mechanisms. Mechanical compaction is further evident from the reductions in the physical dimensions of the samples. Overall, the results obtained show that the nature and degree of any change in the petrophysical properties of the rock samples vary to some degree from one sample to the next. This variation is found to depend on the significance and degree of dominance of the three mechanisms of mineral dissolution, mineral precipitation and mechanical compaction if they occur during the flooding process. The migration of carbonate fines also seems to be an important factor in shaping the post-flood sample properties. The presence of any initial core scale heterogeneity in the pre-flood samples is also believed to be a critical factor controlling the eventual outcome.

    更新日期:2017-12-14
  • Life cycle assessment of post-combustion CO2 capture: A comparison between membrane separation and chemical absorption processes
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-21
    Lorena Giordano, Denis Roizard, Eric Favre

    Carbon capture technologies are regarded as promising options to mitigate CO2 emissions from large point sources, such as power generation facilities and energy intensive industries. However, CO2 capture technologies have several environmental impacts, from the system infrastructure production stage to the end of their lifetime, because of the consumption of resources in the form of materials and energy, as well as the formation of chemical by-products. All these aspects should be taken into account in order to assess and compare the real environmental sustainability of the CO2 capture processes. It is well established that life cycle assessment (LCA) represents a powerful tool to evaluate the most significant environmental impacts of CO2 capture technologies throughout their lifetimes. Using LCA methodology, this study aimed to compare life cycle emissions of membrane separation and chemical absorption processes for the post-combustion capture of one tonne of CO2 from a subcritical coal-fired power plant. Environmental impacts were evaluated considering a hybrid approach for the life cycle inventory, combining physical and economic input data. Simulation results highlighted that life cycle emissions of CO2 capture based on membrane separation process were strongly related to membrane material and thickness of the dense active layer, influencing the net power consumption and membrane area requirement. Membrane configurations investigated allowed to reduce to such an extent environmental impacts compared to CO2 capture based on monoethanoalmine (MEA) absorption. The greatest reduction potential was observed for human toxicity and impacts on freshwater and marine ecosystems, because of the elimination of environmental concerns related to solvent manufacturing and disposal of amine reclaimer wastes.

    更新日期:2017-12-14
  • Some thoughts on Darcy-type flow simulation for modelling underground CO2 storage, based on the Sleipner CO2 storage operation
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-24
    G.A. Williams, R.A. Chadwick, H. Vosper

    We take three flow simulators, all based on Darcy’s Law but with different numerical solver implementations, to assess some of the issues surrounding their use to model underground CO2 storage. We focus on the Sleipner CO2 injection project, which, with its seismic monitoring datasets, provides unique insights into CO2 plume development during a large-scale injection operation. The case studies firstly compare simulator performance in terms of outputs and run-times on carefully matched model scenarios; then we compare numerical with analytical Darcy solutions to explore the potential for modelling simplification; finally we look at the effects of including conservation of energy in the simulations. The initial case-study used simplified axisymmetric model geometry to simulate the upward flux of CO2 through a heterogeneous reservoir, incorporating multiphase flow with coupled CO2 dissolution into formation brine. All three codes produced near-identical results with respect to CO2 migration velocity and total upward CO2 flux at the reservoir top. The second case-study involved 3D modelling of the growth of the topmost layer of CO2 trapped and migrating beneath topseal topography. Again the three codes showed excellent agreement. In the third case-study the simulators were tested against a simplified analytical solution for gravity currents to model the spreading of a single CO2 layer beneath a flat caprock. Neglecting capillary effects, the numerical models showed similar layer migration and geometry to the analytical model, but it was necessary to minimise the effects of numerical dispersion by adopting very fine cell thicknesses. The final case-study was designed to test the non-isothermal effects of injecting CO2 into a reservoir at non-ambient temperature. Only two of the simulators solve for conservation of energy, but both showed a near identical thermal anomaly, dominated by Joule-Thomson effects. These can be significant, particularly where reservoir conditions are close to the critical point for CO2 where property variations can significantly affect plume mobility and also seismic response. In conclusion, the three simulators show robust consistency, any differences far less than would result from geological parameter uncertainty and limitations of model resolution. In this respect the three implementations are significantly different in terms of computing resource requirement and it is clear that approaches with simplified physics will pay rich dividends in allowing more detailed reservoir heterogeneity to be included. Contrary to this, including conservation of energy is heavier on computing time but is likely to be required for storage scenarios where the injectant stream is significantly different in temperature to the reservoir and most critically for shallower storage reservoirs where CO2 is close to its critical point.

    更新日期:2017-12-14
  • Flow-through reactor experiments on basalt-(sea)water-CO2 reactions at 90 °C and neutral pH. What happens to the basalt pore space under post-injection conditions?
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-24
    D. Wolff-Boenisch, I.M. Galeczka

    Recent publications on the successful mineralisation of carbon dioxide in basalts in Iceland and Washington State, USA, have shown that mineral storage can be a serious alternative to more mainstream geologic carbon storage efforts to lock away permanently carbon dioxide. In this study we look at the pore solution chemistry and mineralogy of basaltic glass and crystalline basalt under post-injection conditions, i.e. after rise of the pH via matrix dissolution and the first phase of carbonate formation. Experimental findings indicate that further precipitation of carbonates under more alkaline conditions is highly dependent on the availability of divalent cations. If the pore water is deficient in divalent cations, smectites and/or zeolites will dominate the secondary mineralogy of the pore space, depending on the basalt matrix. At low carbonate alkalinity no additional secondary carbonates are expected to form meaning the remaining pore space is lost to secondary silicates, irrespective of the basalt matrix. At high carbonate alkalinity, some of this limited storage volume may additionally be occupied by dawsonite −if the Na concentration in the percolating groundwater (brine) is high. Using synthetic seawater as a proxy for the groundwater composition and thus furnishing considerable amounts of divalent cations to the carbonated solution, results in massive precipitation of calcite, magnesite, and other Ca/Mg-carbonates under already moderate carbonate alkalinity. More efficient use of the basaltic storage volume can thus be attained by promoting formation of secondary carbonates compared to the inevitable formation of secondary silicate phases at higher pH. This can be done by ensuring that the pore water does not become depleted in divalent cations, even after carbonate formation. Using seawater as carbonating fluid or injection of CO2 into the basaltic oceanic crust, where saline fluids percolate, can reach this goal. However, such an approach needs sophisticated reactive transport modelling to adjust CO2 injection rates in order to avoid too rapid carbonate deposition and clogging of the pore space too close to the injection well.

    更新日期:2017-12-14
  • Heterogeneity, pore pressure, and injectate chemistry: Control measures for geologic carbon storage
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-28
    Thomas Dewers, Peter Eichhubl, Ben Ganis, Steven Gomez, Jason Heath, Mohamad Jammoul, Peter Kobos, Ruijie Liu, Jonathan Major, Ed Matteo, Pania Newell, Alex Rinehart, Steven Sobolik, John Stormont, Mahmoud Reda Taha, Mary Wheeler, Deandra White

    Desirable outcomes for geologic carbon storage include maximizing storage efficiency, preserving injectivity, and avoiding unwanted consequences such as caprock or wellbore leakage or induced seismicity during and post injection. To achieve these outcomes, three control measures are evident including pore pressure, injectate chemistry, and knowledge and prudent use of geologic heterogeneity. Field, experimental, and modeling examples are presented that demonstrate controllable GCS via these three measures. Observed changes in reservoir response accompanying CO2 injection at the Cranfield (Mississippi, USA) site, along with lab testing, show potential for use of injectate chemistry as a means to alter fracture permeability (with concomitant improvements for sweep and storage efficiency). Further control of reservoir sweep attends brine extraction from reservoirs, with benefit for pressure control, mitigation of reservoir and wellbore damage, and water use. State-of-the-art validated models predict the extent of damage and deformation associated with pore pressure hazards in reservoirs, timing and location of networks of fractures, and development of localized leakage pathways. Experimentally validated geomechanics models show where wellbore failure is likely to occur during injection, and efficiency of repair methods. Use of heterogeneity as a control measure includes where best to inject, and where to avoid attempts at storage. An example is use of waste zones or leaky seals to both reduce pore pressure hazards and enhance residual CO2 trapping.

    更新日期:2017-12-14
  • Modelling acid attack of oilwell cement exposed to carbonated brine
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-12-01
    Joaquín Liaudat, Ariadna Martínez, Carlos M. López, Ignacio Carol
    更新日期:2017-12-14
  • Effect of wettability heterogeneity and reservoir temperature on CO2 storage efficiency in deep saline aquifers
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-29
    Emad A. Al-Khdheeawi, Stephanie Vialle, Ahmed Barifcani, Mohammad Sarmadivaleh, Stefan Iglauer
    更新日期:2017-12-14
  • CO2 sequestration with limited sealing capability: A new injection and storage strategy in the Pearl River Mouth Basin (China)
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-12-06
    Niklas Heinemann, R. Stuart Haszeldine, Yutong Shu, R. Jamie Stewart, Vivian Scott, Mark Wilkinson

    Storing CO2 for geological timescales is crucial to delivering decarbonisation of industrial economies aligned with global climate change mitigation objectives. This requires CO2 injection into a large subsurface pore space overlain by a high capillary entry pressure seal rock to prevent CO2 escape. Such formations occur abundantly in productive hydrocarbon basins such as the North Sea. However, these geological conditions for CO2 storage are unavailable close to some large CO2 emitting economic areas in China. We identify this problem and innovate a solution for the example of the Pearl River Mouth Basin (China). This offshore basin has an estimated effective storage capacity of hundreds of Gt CO2 based on reservoir pore volumes. Production and geological data of three oil fields of the Huizhou hydrocarbon cluster are analysed as analogues for large-scale aquifer storage of CO2. Results suggest the injection and storage of CO2 in individual trap structures will perform poorly, due to thin reservoir layers, small structural traps, and indications that the cap rocks may have only limited sealing capability. To address this a novel alternative CO2 sequestration strategy, based on multi reservoir layer injection and dispersion trapping, is recommended to exploit the vast available pore space for CO2 storage.

    更新日期:2017-12-14
  • CO2-brine flow-through on an Utsira Sand core sample: Experimental and modelling. Implications for the Sleipner storage field
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-12-06
    Ismael Falcon-Suarez, Giorgos Papageorgiou, Andy Chadwick, Laurence North, Angus I. Best, Mark Chapman

    Sleipner (North Sea) is the world’s first commercial-scale carbon capture and storage (CCS) project, active since 1996, with ∼17 million tonnes of CO2 stored. The main reservoir, Utsira Sand, constitutes an ideal host formation of exceptionally high porosity-permeability and large lateral extent. However, the extensive seismic time-lapse, gravity and electromagnetic monitoring surveys deployed at Sleipner have not been well-supported by laboratory measurements. Here, we investigate the geophysical and geomechanical response of an Utsira core sample for the first time, using controlled inflation/depletion cycles at variable CO2-to-brine fractional flow rates. Ultrasonic P-wave velocities and attenuations are measured together with electrical resistivity (converted into CO2-saturation), along with continuous axial and radial strain monitoring. Ultrasonic velocity and attenuation data were simultaneously inverted and results extrapolated to field-scale seismic-frequencies using a new rock physics theory, which combines patchy fluid distribution and squirt flow effects. It provides a velocity-saturation relationship of practical importance to CO2 plume monitoring. Furthermore, by combining ultrasonic and deformation data, we report empirical relations between pore pressure changes and geomechanical effects in the reservoir, for different saturation ranges. Our dataset complements and constrains existing geophysical monitoring surveys at Sleipner and, more generally, improves the understanding of shallow weakly-cemented sand reservoirs.

    更新日期:2017-12-14
  • Impact of impurities on CO2 storage in saline aquifers: Modelling of gases solubility in water
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-12-06
    Martha Hajiw, Jérôme Corvisier, Elise El Ahmar, Christophe Coquelet

    Flue gas captured contains different impurities (N2, O2, SO2, NO etc) and their concentrations depend on the capture process and the industrial sector. Moreover, the presence of impurities may change the thermophysical properties of the stream and therefore impact the conditions of CO2 storage. The aim of the paper is to investigate the solubility in water of carbon dioxide and some chosen impurities. In this work VLE calculations using a geochemical model (Corvisier, 2013) and two group contribution (GC-PR-CPA (Group Contribution-Peng Robinson-Cubic Plus Association) (Hajiw, 2014 and Hajiw et al., 2015) and E-PPR78 (Qian et al., 2013) equations of state) models are compared.

    更新日期:2017-12-14
  • Electromagnetic separation of heat stable salt from gas sweetening amine
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-12-12
    Fadi Alnaimat, Emad Alhseinat, Fawzi Banat

    This paper aims at the development and application of electromagnetic-mechanical salt removal (EMSR) process for the removal of Heat Stable Salt (HSS) from Gas Sweetening Amine. The operation of the EMSR process is investigated numerically to examine its efficiency under different operating conditions. The mathematical approach used for the EMSR modeling is based on solving the Navier–Stokes equations using Eulerian approach, and solving the HSS movement using Lagrangian approach. The important parameters that affect the separation process are examined using the developed model. The study results show that the EMSR process efficiency is enhanced with the increase in MDEA solution temperature. It is found that the decrease in MDEA concentration improves the removal of the HSS. In the study, it is found that around 70% removal of the HSS can be achieved using the EMSR. It is demonstrated that EMSR can be used effectively to separate dissolved HSS from MDEA solution.

    更新日期:2017-12-14
  • Mass flow measurement of gas-liquid two-phase CO2 in CCS transportation pipelines using Coriolis flowmeters
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-12-12
    Lijuan Wang, Yong Yan, Xue Wang, Tao Wang, Quansheng Duan, Wenbiao Zhang

    Carbon Capture and Storage (CCS) is a promising technology that stops the release of CO2 from industrial processes such as electrical power generation. Accurate measurement of CO2 flows in a CCS system where CO2 flow is a gas, liquid, or gas-liquid two-phase mixture is essential for the fiscal purpose and potential leakage detection. This paper presents a novel method based on Coriolis mass flowmeters in conjunction with least squares support vector machine (LSSVM) models to measure gas-liquid two-phase CO2 flow under CCS conditions. The method uses a classifier to identify the flow pattern and individual LSSVM models for the metering of CO2 mass flowrate and prediction of gas volume fraction of CO2, respectively. Experimental work was undertaken on a multiphase CO2 flow test facility. Performance comparisons between the general LSSVM and flow pattern based LSSVM models are conducted. Results demonstrate that Coriolis mass flowmeters with the LSSVM model incorporating flow pattern identification algorithms perform significantly better than those using the general LSSVM model. The mass flowrate measurement of gas-liquid CO2 is found to yield errors less than ±2% on the horizontal pipeline and ±1.5% on the vertical pipeline, respectively, over flowrates from 250 kg/h to 3200 kg/h. The error in the estimation of CO2 gas volume fraction is within ±10% over the same range of flow rates.

    更新日期:2017-12-14
  • Prediction of CO2 leakage risk for wells in carbon sequestration fields with an optimal artificial neural network
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-12-12
    Ben Li, Fujian Zhou, Hui Li, Andrew Duguid, Liyong Que, Yanpeng Xue, Yanxin Tan

    Carbon Capture and Storage (CCS) is a key climate mitigation technology. Leakage of the injected CO2 is one of the major environmental concerns. The potential for CO2 leakage from wells is one of the critical risks identified in geological CO2 sequestration. The objective of this study is to develop a computerized statistical model with the neural network algorithm for predicting the probability of long-term leak of wells in CO2 sequestration operations. Well design and operation data for over 500 CO2 exposed wells were generated from the West Hastings oil field and Oyster Bayou oil field in southern Texas, USA. The well integrity conditions were assessed by analyzing the well attribute data (well type, well age, CO2 exposed period, well construction details and materials), well operation histories and regulatory changes. Leakage-safe Probability Index (LPI) was assigned to individual wells. A computerized statistical model with network algorithm was developed based on data processing and grouping. Comprehensive training and testing of the model were carried out to ensure that the model was accurate and efficient enough for predicting the probability of long-leak of wells in CO2 sequestration operations. The accuracy of the trained neural network for well leakage prediction was also verified by the field operation in the Cranfield Field, Mississippi, USA. The developed neural network model can improve the efficiency of the storage operations by predicting the risk of CO2 leakage in the current exposed wells. In addition, it can also contribute in developing best practices standards by proposing recommendations for well construction in future wells.

    更新日期:2017-12-14
  • Public perceptions of carbon capture and storage in Canada: Results of a national survey
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-05
    Amanda D. Boyd, Jay D. Hmielowski, Prabu David

    Carbon dioxide capture and geological storage (CCS) is one strategy to reduce greenhouse gas emissions that has attracted interest from government and industry in Canada. A key factor that will determine if organizations implement CCS is whether the public support the development of the technology. Public views and understandings of key issues surrounding CCS were assessed via Internet and phone on a representative sample of 1479 Canadians. We examined descriptive statistics to understand public perceptions of CCS and applied regression models to assess how risk perceptions, perspectives of climate change and trust in government relate to the support for or opposition to CCS development and funding for the technology. Results indicate there is low support for CCS in Canada; however, findings varied when taking into account participants’ proximity to projects. Furthermore, the publics’ perceptions of the risk and benefits of CCS influenced support for or opposition to the technology. We discuss implications of public perceptions on the development and deployment of CCS and provide recommendations for communication strategies about the technology.

    更新日期:2017-12-14
  • Moving bed adsorption process based on a PEI-silica sorbent for CO2 capture
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-05
    Wonho Jung, Junhyung Park, Kwang Soon Lee

    A polyethylenimine (PEI)-silica adsorbent-based true moving bed adsorption process with a heat integration scheme was investigated as an energy conservative CO2 capture process. The process was configured using four separate beds with internal plate heat exchangers for adsorption, cooling, desorption and heating. An in-house steady-state simulator was constructed to analyze process behaviors, which focused on the energy demand and bed size under various operating conditions. A recently developed amine-functionalized adsorbent, 0.37EB-PEI, which uses silica fume as a support, was utilized in the process.

    更新日期:2017-12-14
  • Temperature analysis for early detection and rate estimation of CO2 wellbore leakage
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-05
    Yilin Mao, Mehdi Zeidouni, Ian Duncan

    Wellbore leakage of carbon dioxide (CO2) injected into storage zones can induce significant temperature anomalies. These thermal signals arise from expansion of the leaking CO2 associated with the pressure drop across the leak, known as the Joule-Thomson effect, which has the potential to reveal the nature of leakage and determine the wellbore leakage rate of CO2. We investigate the strength of the temperature signal as a function of leakage rate and develop a control volume analysis to relate these two in the complex two-phase leakage conditions. This analytical thermal model for CO2 leakage enables quick analysis with sufficient accuracy to estimate the leakage rate. The application range of this approach is identified from the results of comprehensive investigations. The nature of the thermal signal is sensitive to the balance between the Joule-Thomson effect and heat conduction. The ratio of these two effects and newly defined JT/cond Number provide general criteria for the applicability of modeling these thermal signals in the range of 40–90% and 1.6-4, respectively. Furthermore, in the case of higher leakage rate, we extend the analytical model to predict the leakage transmissibility with improved accuracy compared to the direct rate estimation from leakage thermal model in this scenario. The general procedure and flow chart to apply the proposed approach to a practical problem are provided, which is suitable for both injection and post-injection periods for a CO2 storage project. This analytical model breaks a new ground to apply recent temperature wellbore monitoring developments for CO2 leakage detection and characterization purposes. Field applications of this model can complement other leakage rate estimation techniques and be an essential part of the CO2 leakage detection tool if other approaches are not viable.

    更新日期:2017-12-14
  • Supercritical CO2 injection and residence time in fluid-saturated rocks: Evidence for calcite dissolution and effects on rock integrity
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-05
    Lucas Pimienta, Lionel Esteban, Joel Sarout, Keyu Liu, Jérémie Dautriat, Claudio Delle Piane, Michael B. Clennell

    CO2 injection and storage in geological reservoirs is an attractive prospect for mitigating the anthropogenic production of greenhouse gases and global warming. The technology could lead to mineral precipitation and therefore stable storage over geological time scales. This contribution investigates the evolution of three calcite-rich reservoir rock analogues during injection of and exposure to supercritical CO2 (scCO2), i.e., two limestones (Tuffeau and Savonnieres) and a synthetic calcite-cemented sandstone (CIPS). Three types of exposure protocols have been conducted: (i) scCO2 injection and a four-hour residence time in an initially dry rock; (ii) scCO2 injection and a two-hour residence time in an initially brine-saturated rock; and (iii) scCO2 injection and a four-hour residence time in an initially brine-saturated rock. Two aspects are monitored during these experiments: (i) the evolution of the pore fluid chemical composition; and (ii) the evolution of the rocks’ physical properties (i.e. porosity, permeability, P-wave velocity and electrical resistivity). Additionally, some scCO2 injection and exposure experiments in the brine-saturated rocks have been conducted using X-ray tomographic monitoring. X-ray tomographic monitoring suggests that scCO2 first displaces the water, leading to an average water saturation of about 70–90%. Then, scCO2 dissolves in the pore brine, leading to a homogeneous decrease by about 3% in water saturation of the sample. As a result, the pore brine acidifies even after 2 h of exposure only, which leads to calcite dissolution and a significant increase in the brine’s concentration in calcium cations. For the samples and most exposure experiments, evidence of calcite dissolution is inferred from the measured physical properties. For the brine-saturated Tuffeau limestone and CIPS sandstone, calcite dissolution leads to significant mechanical weakening. For the brine-saturated Savonnieres limestone, the sample subject to two-hour residence time shows evidence of calcite dissolution, whereas the sample after four-hour residence time does not. Calcite re-precipitation could be the cause of this unexpected response after four hours.

    更新日期:2017-12-14
  • Compaction and mechanical strength of Middle Miocene mudstones in the Norwegian North Sea – The major seal for the Skade CO2 storage reservoir
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-05
    Mohammad Nooraiepour, Beyene Girma Haile, Helge Hellevang

    This study has investigated petrophysical, acoustic and geomechanical properties of Middle Miocene mudstones in the Norwegian North Sea as the primary caprock for Skade CO2 storage reservoir. To evaluate the seal properties, we analyzed collected drill cuttings and measured well logs from well 16/4-1, in addition to an extensive well log database in the Northern North Sea. The studied caprock was identified as siliceous ooze-rich mudstones with low bulk density, high shear wave velocity, and low Vp/Vs ratio. The abundance of siliceous skeletal material resulted in a significant shift from the overall trend of mudstones within the Hordaland Group. The estimated scenarios for S-wave velocity depicted that the ooze-rich mudstones have the highest brittleness of the Hordaland Group semi-consolidated rocks. The brittleness indices in well 16/4-1 illustrated that the mineralogical composition-based indices significantly overestimate brittleness compared to the elastic-based indices. While the caprock for Skade CO2 storage reservoir showed an overall ductility, the bottom 30 m demonstrated an increased brittleness profile. The more brittle ooze-rich mudstones also indicated the lowest estimation of fracture pressure compared to other scenarios. The research outcomes emphasize on the influence of mudstone type and microstructure on the macroscale physical properties of shallow semi-compacted CO2 caprocks.

    更新日期:2017-12-14
  • Exploring CO2 capture from pressurized industrial gaseous effluents in membrane contactor-based pilot plant
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-05
    Antonio Comite, Camilla Costa, Marco Demartini, Renzo Di Felice, Maddalena Oliva
    更新日期:2017-12-14
  • Process integration study of tail-end Ca-Looping process for CO2 capture in cement plants
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-05
    E. De Lena, M. Spinelli, I. Martínez, M. Gatti, R. Scaccabarozzi, G. Cinti, M.C. Romano
    更新日期:2017-12-14
  • Design of boil-off CO2 re-liquefaction processes for a large-scale liquid CO2 transport ship
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-05
    Yeongbeom Lee, Kye Hyun Baek, Sanggyu Lee, Kyusang Cha, Chonghun Han

    This paper studies re-liquefaction properties of CO2 and introduces feasible designs of boil-off CO2 re-liquefaction processes suited for a large-scale transport ship. There are additional design considerations besides re-liquefaction efficiency due to the ship. Firstly, re-liquefaction facilities should be located within a limited space of a transport ship, which induces the number of main equipment as a constraint. Secondly, if an external closed-loop refrigeration is necessary, refrigerants should be re-chargeable and safe. From this perspective, CO2 would be the most appropriate one due to the availability in a liquefied CO2 ship and its safety if it can have similar performance to conventional refrigerants. According to CO2 liquefaction simulation, CO2 as a refrigerant shows similar performance to C3H8 and NH3 with additional 5–7% power consumptions. With this preliminary investigation, four boil-off CO2 re-liquefaction processes for a large-scale transport ship are designed. A re-liquefaction process which employs a distillation column shows 99.7% of re-liquefaction fraction but it has disadvantages of power consumption and the number of main equipment. On the contrary, another re-liquefaction process which has an external closed-loop refrigeration cycle with a CO2 refrigerant meets the re-liquefaction target (>70.0%) with the lowest power consumption. This process also requires nominal level of the number of main equipment and the capital expenditure. Given these results, an external closed-loop CO2 refrigeration cycle based re-liquefaction process is expected to be appropriate for a large-scale liquid CO2 transport ship. Hopefully, the results addressed in this study will contribute to further development of liquefied CO2 transport ships in near future.

    更新日期:2017-12-14
  • Aqueous phase tracers for monitoring fluid mixing in geological reservoirs: Results from two field studies
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-08
    Jay R. Black, Hong P. Vu, Ralf R. Haese

    Dissolved species are widely used to determine the degree of fluid mixing and fluid-rock reactions in geological reservoirs where differences are observed in groundwater chemistry. Likewise these components can be added artificially to injection waters to act as aqueous phase tracers in field tests. Here we report results from two field studies where aqueous phase tracers were applied. The first field site was located in the Darling Basin of NSW where new exploration wells were drilled to determine if suitable CO2 storage reservoirs could be identified. In this field study fluorescein was continuously added to a drill mud used during the drilling of an exploration well. After drilling the well, a wireline tool was used to collect formation water from different depths in the well and the residual fluorescein concentration was used to determine contamination of formation waters by drill mud. The composition of dissolved solids in the in situ formation water samples were close to 100% of those found in the final drill mud composition, whereas, c. 70–83% of the drill mud fluorescein concentration was observed in the in situ water samples. This indicated significant drill mud contamination of samples collected by the wireline tool, and potential non-conservative behavior of the fluorescein. The second field site was located at the CO2CRC Otway field site near Nirranda South in Victoria, Australia. Here, a range of aqueous phase tracers (fluorescein, Na+, Cl−, Br−, Sr2+ and Li+) were added to a CO2-saturated injection water and analysed in the back-produced water of a push-pull experiment (Otway 2B Extension) in order to determine the degree of mixing between injection and formation water. Fluorescein behaved in a non-conservative manner under the mild acidic conditions (in situ pH = 4.5), most likely due to adsorption to mineral surfaces. Scatter in the Na+ and Cl− concentrations made their interpretation problematic, while some loss of Sr2+ is inferred possibly involving exchange with minerals in the reservoir. In contrast, Br− and Li+ showed conservative behavior and are recommended for future tracer studies in reservoirs where pH is variable.

    更新日期:2017-12-14
  • Reinjection of greenhouse gases into geothermal reservoirs
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-14
    Eylem Kaya, Sadiq J. Zarrouk

    This work addresses the feasibility of reinjecting H2S and CO2, captured and dissolved in effluents from the geothermal field, back into the geothermal reservoir. A series of numerical modelling scenarios was used to assess the effect of NCG (non-condensable gases) reinjection on energy recovery, understand permanent trapping, and forecast potential NCG breakthrough into production wells. Although the gas species from geothermal systems typically have moderate solubility in water, formation of gas phases at lower pressures and/or the shallow subsurface requires careful consideration of the injection rate and composition of NCG. Possible fluid paths and distribution of gas components were investigated to estimate the NCG storage capability of a reservoir, and evaluate the potential risk of the reinjected NCG growing into fingers that may lead to an early breakthrough or potential leakage to the ground surface. Modified versions of benchmark geothermal reinjection models were constructed with initial conditions of a liquid-dominated geothermal system. The results obtained show that the effects of injection depend on the reinjection and production wells arrangement and the recharge conditions. The risk of leakage to the surface is very limited since the injected NCG remain in the liquid phase.

    更新日期:2017-12-14
  • Indirect ocean capture of atmospheric CO2: Part I. Prototype of a negative emissions technology
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-20
    Charles-Francois de Lannoy, Matthew D. Eisaman, Arun Jose, Stephen D. Karnitz, Richard W. DeVaul, Kathy Hannun, Jessy L.B. Rivest

    We present the design, construction, characterization, and analysis of a prototype process for a novel electrochemical platform of candidate negative emissions technologies (NETs), termed indirect ocean capture. The IOC technologies remove carbon dioxide gas from the atmosphere by leveraging both air-ocean gas exchange and the pH sensitivity of the ocean’s carbonate buffer system. The system characterized in this paper enables two configurations that capture CO2 either as a pure gas or as a solid mineral. Both configurations use the acid and base produced by the membrane electrodialysis of ocean water. The first configuration, termed the ‘acid process’, acidifies ocean water or brine to shift the carbonate buffer system towards dissolved CO2 gas, which is vacuum stripped from the acidified brine. The second configuration, termed the ‘base process’, adds base to the brine to shift the carbonate buffer system towards carbonate ions, which precipitates as CaCO3. A closed loop cycle is achieved by returning this decarbonized and alkalinized brine to the ocean for additional CO2 absorption from the air. Our evaluation of this prototype scale system focused on the parameters that have the most influence on the ultimate cost of the extracted CO2. In a concurrent techno-economic study, the most cost-sensitive parameters were shown to be the efficiencies of the anion and cation exchange membranes, the number and orientation of CO2 extraction membranes, and the volume of base required for CaCO3 precipitation. The measured parameters provide target values for commercial deployment. The experiments in this study were used to inform the concurrent techno-economic study that quantifies in detail the projected cost of avoided CO2 achievable with this process.

    更新日期:2017-12-14
  • Stiff cement, soft cement: Nonlinearity, arching effect, hysteresis, and irreversibility in CO2-well integrity and near-well geomechanics
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-11-16
    Alexandre Lavrov

    During geologic CO2 storage, integrity of injection wells is of utmost importance. Tensile radial stresses at casing-cement and cement-rock interfaces caused by relatively cold CO2 flowing down the tubing may induce debonding and create microannuli. Microannuli represent potential leakage paths. Thermal stresses can be reduced by using softer cement (“flexible cement”). Numerical simulations show that benefits of soft cement are more pronounced in relatively hard (stiff) rocks. In a very soft rock, there might be as good as no effect of lowered cement stiffness on thermal stresses, while tensile strength of such cement might be severely reduced. Thus, to fully benefit from soft (flexible) cement in CO2-injection wells, such cement should be set against sufficiently stiff rock. Effect of rock stiffness on tensile radial stress build-up during cooling is stronger than that of cement stiffness. As a result, the benefits of carefully adjusting the cement stiffness might be offset by natural variation in the rock properties. Soft cement also reduces the stress build-up in the cement sheath caused by far-field in-situ stress variation during injection. The mechanism here is the arching effect in the near-well area: the rock effectively shields the cement sheath from in-situ stress changes. In order to fully exploit benefits of soft cement here, the rock again must be sufficiently stiff.

    更新日期:2017-12-14
  • Conceptual design of an off-shore topside CO2 injection system
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-09-18
    Umer Zahid, Yong Heon Kim, Usama Ahmed, Jinjoo An

    Carbon capture and storage (CCS) is one of the dominant technologies to tackle the global warming issue. The transport of CO2 for geological storage may become economically feasible by ship when the storage site location is off-shore and installment of an off-shore pipeline requires a huge capital cost. Ship transportation requires the captured CO2 to be in liquid phase under pressurized thermodynamic conditions. The injection of liquid CO2 into the geological reservoir involves pressurization and heating in order to maintain the safe well head operating conditions. This study presents two alternative top side injection process designs that can reduce the power requirement compared to the base case design. The base case design and alternative designs are simulated using Aspen HYSYS® in order to decide the process design variables. The results show that the well head temperature of 5 °C should be maintained to avoid any hydrate formation in the injection well or at the well outlet, while, utilizing the minimum amount of energy for the injection. The study employed two-stage rankine cycle in order to extract the cold energy available from the liquid CO2 before its injection into the reservoir. The alternative designs also proposed to utilize a vapor return line in order to maintain the CO2 vessel pressure within safe limits by performing a dynamic simulation. The results show that the alternative design 1 and alternative design 2 consume almost 28% and 27.9% less power compared to that of the base case design. The specific cost per unit ton of CO2 injected for the three designs came out to be 0.75 $, 0.69 $ and 0.69 $ respectively. Finally, a sensitivity analysis has been done in order to investigate the effect of some important variables in the study.

    更新日期:2017-12-14
  • Analysis of CO2 transport including impurities for the optimization of point-to-point pipeline networks for integration into future solar fuel plants
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-09-18
    Alexandros Lemontzoglou, Grigorios Pantoleontos, Akrivi G. Asimakopoulou, Nikolaos I. Tsongidis, Athanasios G. Konstandopoulos

    The present work aims to establish a generic model for calculating point-to-point pipelines transport of CO2 mixtures. This study improves upon highly-detailed existing models by providing further engineering and economics features, such as the rights-of-way portion of the pipeline cost, and the implicit Darcy-Weisbach-Colebrook-White equation for the calculation of the friction and the pressure drop within the pipeline. The model is applied to binary mixtures of CO2 with 2%mol H2 and 4%mol N2 concentrations, roughly resembling oxy-fuel and pre-combustion CO2-capture binary mixtures, respectively. Analytical expressions of the physical properties of CO2 mixtures are combined with engineering and economic aspects of the pipeline facility, in order to determine the optimal pipeline diameter for pipeline capacity within the range of 150–2000 kg/s and for transport distances from 500 to 2000 km. Pure CO2 transport is used as a base-case in order to replicate existing literature data, while the calculated data are interpolated to derive correlations of the minimum levelized cost with respect to transport capacity and distance for all mixtures examined. It is shown that there is a slight impact at the expense of the economics of the process when considering impurities. A breakdown of the cost elements involved in the transportation chain of CO2 is conducted, and the influence of the mass flowrate and the length of the pipeline on the process economics is examined.

    更新日期:2017-12-14
  • Trade-offs in cost and emission reductions between flexible and normal carbon capture and sequestration under carbon dioxide emission constraints
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-09-18
    Michael T. Craig, Haibo Zhai, Paulina Jaramillo, Kelly Klima

    Relative to “normal” amine-based post-combustion capture carbon and sequestration (CCS), flexible CCS adds a flue gas bypass and/or solvent storage system. Here, we focus on flexible CCS equipped with a solvent storage system. A primary advantage of flexible over normal CCS is increased reserve provision. However, no studies have quantified system-level cost savings from those reserves, which could drive the public benefits and rationale for policy support of flexible over normal CCS. Here, we quantify total power system costs, including generation, reserve, and capital costs, as well as carbon dioxide (CO2) emissions of generator fleets with flexible versus normal CCS. We do so under a moderate and strong CO2 emission limit. Relative to normal CCS, solvent storage-equipped flexible CCS reduces system-wide operational plus annualized CCS capital costs but increases system-wide CO2 emissions under the moderate limit, whereas it reduces system-wide costs and emissions under the strong limit. Under both limits, we find that reductions in reserve costs constitute 40–80% of the reductions in total operational costs with flexible CCS rather than normal CCS. Thus, flexible versus normal CCS deployment decisions pose cost and emissions tradeoffs to policymakers under a moderate emission limit as well as tradeoffs between near- and long-term policy objectives.

    更新日期:2017-12-14
  • CO2 capture from natural gas power plants using selective exhaust gas recycle membrane designs
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-09-20
    Richard W. Baker, Brice Freeman, Jay Kniep, Xiaotong Wei, Tim Merkel
    更新日期:2017-12-14
  • CO2 geological sequestration: Displacement behavior of shale gas methane by carbon dioxide injection
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-09-23
    Peili Huo, Dengfeng Zhang, Zhen Yang, Wei Li, Jin Zhang, Shuaiqiu Jia

    Carbon dioxide (CO2) sequestration in deep shale reservoirs with enhanced shale gas methane (CH4) recovery contributes to both CH4 recovery and CO2 emission mitigation. In this work, the adsorption behaviors of pure CH4 and CO2 on shales, and the displacement behaviors of CH4 adsorbed on shales by CO2 injection were investigated. The single component adsorption indicates that the simplified Ono-Kondo lattice model can well describe both CH4 and CO2 adsorption on shales. The maximum adsorption capacity of CH4 obtained from the simplified Ono-Kondo lattice model shows significant linear correlation with the micropore parameters of shales, while this linear correlation is weak for CO2. The investigation on the displacement behaviors based on the improved experimental procedure and data processing method raised in this work confirms that CH4 adsorbed on shales can be displaced by CO2, which provides the experimental evidence for the feasibility of CO2 sequestration in shale reservoirs with enhanced CH4 recovery. The amounts of recovered CH4 and stored CO2 increase with CO2 injection pressure. The recovery yield of CH4 due to CO2 injection is higher for shales with smaller micropore parameters or lower adsorption performance. The microscopic mechanism of the displacement process is strongly related to the injection pressure of CO2. Based on the conceptual model established for the process of CH4 adsorbed on shales displaced by CO2 injection, it is recommended to inject CO2 after partial desorption of CH4, which can improve CH4 recovery and CO2 sequestration of the target shale reservoirs.

    更新日期:2017-12-14
  • Performance and cost of CCS in the pulp and paper industry part 2: Economic feasibility of amine-based post-combustion CO2 capture
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-09-26
    Kristin Onarheim, Stanley Santos, Petteri Kangas, Ville Hankalin

    The economic feasibility of retrofitting an amine based post-combustion CO2 capture process to an existing Kraft pulp mill and an existing integrated pulp and board mill has been assessed. This study builds on the technical assessment of the energy performance of the mills when retrofitting a post-combustion CO2 capture process by Onarheim et al. (2017). Between 75 to 100% of the CO2 emissions from the pulp and paper industry originate from the combustion of biomass. If the raw material is sourced sustainably, these emissions are categorized as carbon neutral. Applying sustainably managed biomass in the pulp and paper processes and capturing the resulting CO2 for permanent storage enables the industry to go carbon negative. In this study, the economic impact of retrofitting CO2 capture from the flue gases of the recovery boiler, the multi-fuel boiler and the lime kiln were assessed. The levelized cost of pulp and the cost of CO2 avoided were evaluated based on six different scenarios varying the CO2 tax, incentives for renewable electricity production, with and without recognizing biogenic CO2 emissions as neutral (exempting CO2 emissions from tax or not), and rewarding captured and permanently stored CO2 with negative emissions credit. Results show that the pulp and paper industry has a potential for realizing feasible implementation of large-scale industrial Bio-CCS. For cases where 60–90% of total site CO2 emissions are captured, the cost of avoided CO2 amounts to 52–66 €/t for the Kraft pulp mill and 71–89 €/t for the integrated pulp and board mill. The cost of avoided CO2, and thus the realization of Bio-CCS in the pulp and paper industry, is strongly dependent on prevailing policy frameworks such as the EU ETS. In order to reach a levelized cost of pulp similar to the reference mill without CO2 capture, a negative CO2 emission credit of 60–70 €/t CO2 for the Kraft pulp mill and 70–80 €/t CO2 for the integrated pulp and board mill will be required. As long as biogenic CO2 emissions that are captured and permanently stored are not recognized as negative and rewarded accordingly there is no economic incentive for the owners of pulp and paper mills to implement CCS. The only way to get the pulp and paper industry to implement and deploy Bio-CCS will need the support of the decision-makers in promoting the right policy framework and regulations to encourage the investment such as strong incentives for negative emissions which are bankable during the long term operation of the mills.

    更新日期:2017-12-14
  • Different flow behavior between 1-to-1 displacement and co-injection of CO2 and brine in Berea sandstone: Insights from laboratory experiments with X-ray CT imaging
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-10-04
    Yi Zhang, Tetsuya Kogure, Osamu Nishizawa, Ziqiu Xue

    In this study, we compare the changes in CO2 saturation and pressure drop for two modes of injections: (i) a displacement of brine by supercritical CO2 injection (1-to-1 displacement), and (ii) a forced co-current injection of supercritical CO2 and brine at the same flow ratio (co-injection), respectively, in a laboratory core-flooding experiment using a Berea sandstone sample. The Berea sandstone sample showed a weak bedding structure that consists of high- and low- porosity layers. The main flow direction was set perpendicular to the bedding layers. We utilized the X-ray CT technique to image the rock interior and obtain the information of local porosity and saturation of each voxels in a three dimensional volume. The results show that the co-injection needs a much higher pressure drop to maintain the constant flow rate than the 1-to-1 displacement at similar saturation degrees. Moreover, the co-injection shows significant fluctuations in saturation and pressure drop, whereas the 1-to-1 displacement shows more gradual and monotonous changes. The spontaneous fluctuations in saturation and pressure drop during co-injection are basically coincident in temporal pace, and can be explainable by the intermittent flow of brine and CO2 as shown in differential saturation images. Furthermore, the X-ray images show that the CO2 mainly flows through built flow pathway during the 1-to-1 displacement; whereas the CO2 flows near uniformly and does not strictly rely on pore size and capillarity during the co-injection. CO2 saturation distributes more uniform among image pixels during the co-injection. These dissimilarities between the co-injection and 1-to-1 displacement suggest differences in fluid flow mechanism between them. In the 1-to-1 displacement, the pathway of CO2 flow was created by the forward motion of CO2 over the capillary pressure force. CO2 preferred to first percolating through large-size pores and gradually expanded the percolation region while the CO2 saturation grew. In this process, the displaced brine mainly flowed in its remained phase-pathway–less phase interference occurred. The connection of flow pathway for CO2 naturally satisfied the maintaining of the flow rate. In contrast, during the co-injection, both phases flowed in the pore space. The connection of the phase-pathway was affected by the phase snap-off effect. The transport efficiency of such a partially disconnected flow-pathway was significantly lower than the 1-to-1 displacement case, leading to that much higher drive force of pressure drop was necessary to let the fluids flow at setting rates. Nevertheless, the reachability of CO2 to low-porosity sites during the co-injection was higher than during the 1-to-1 displacement. Our findings are important for understanding of co-injections in applications of relative permeability measurement, and enhanced efficiency in capillary trapping, usage of pore space in CO2 geological storage and in oil recovery.

    更新日期:2017-12-14
  • Performance and energy cost evaluation of an integrated NH3-based CO2 capture-capacitive deionization process
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-10-04
    Asad Ullah, Muhammad Wajid Saleem, Woo-Seung Kim

    A capacitive deionization (CDI) device was proposed for NH3-based CO2 absorption-desorption process, to reduce the stripper regeneration energy. A rate-based model, RateFrac, was developed for the absorber, along with an equilibrium-based model, RadFrac, for the stripper. The model was verified, and the results have shown good agreement with experimental data. The CO2 capture process, which is integrated with CDI, was simulated and compared with a non-CDI CO2 capture process based on regeneration energy. Operating parameters such as flow rate, lean CO2 loading, and ammonia concentration in the lean solvent were used to analyze the integrated model. Stripper regeneration energy can be reduced by as much as 37.5% by using the CDI setup. Moreover, energy cost estimation was performed using two heat sources (natural gas and coal). CDI saved a maximum of 31% of the energy costs for a natural gas–fired boiler and 12.3% of the energy costs for a coal-based boiler.

    更新日期:2017-12-14
  • Wettability of nano-treated calcite/CO2/brine systems: Implication for enhanced CO2 storage potential
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-09-28
    Sarmad Al-Anssari, Muhammad Arif, Shaobin Wang, Ahmed Barifcani, Maxim Lebedev, Stefan Iglauer

    Nanofluids are proven to be efficient agents for wettability alteration in subsurface applications including enhanced oil recovery (EOR). Nanofluids can also be used for CO2-storage applications where the CO2-wet rocks can be rendered strongly water-wet, however no attention has been given to this aspect in the past. Thus in this work we presents contact angle (θ) measurements for CO2/brine/calcite system as function of pressure (0.1 MPa, 5 MPa, 10 MPa, 15 MPa, and 20 MPa), temperature (23 °C, 50 °C and 70 °C), and salinity (0, 5, 10, 15, and 20% NaCl) before and after nano-treatment to address the wettability alteration efficiency. Moreover, the effect of treatment pressure and temperature, treatment fluid concentration (SiO2 wt%) and the period of nano-treatment on the wettability of calcite is examined. We find that nano-treatment alters the wettability significantly i.e. intermediate-wet calcite turns strongly water-wet after treatment (e.g. at 20 MPa and 50 °C, θ = 64° for intermediate-wet calcite, and θ = 28° for nano-treated calcite). Consequently, pre-injection of nanofluids will significantly enhanced the storage potential. It was also found that the permanent shift in wettability after nano-treatment is a function of treatment conditions including temperature, pressure, and treatment duration time and that surfaces treated under high pressure and low temperature yield better wettability alteration efficiency. We point out that the change in wettability is attributed to the changes in surface properties of the nano-treated sample. The results of the study thus depict that nanoparticles can significantly enhance storage potential and de-risk storage projects.

    更新日期:2017-12-14
  • Carbon geosequestration in limestone: Pore-scale dissolution and geomechanical weakening
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-10-02
    Maxim Lebedev, Yihuai Zhang, Mohammad Sarmadivaleh, Ahmed Barifcani, Emad Al-Khdheeawi, Stefan Iglauer

    Carbon dioxide geosequestration in deep saline aquifers or oil and gas reservoirs is a key technology to mitigate anthropogenic greenhouse gas emissions. Porous carbonate rock is a potential host rock for CO2 storage; however, carbonate rock chemically reacts when exposed to the acidic brine (which is created by the addition of CO2, CO2-saturated brine). These reactive transport processes are only poorly understood, particularly at the micrometre scale, and importantly how this affects the geomechanical rock properties. We thus imaged a heterogeneous oolitic limestone (Savonnières limestone) core before and after flooding with brine and CO2-saturated brine at representative reservoir conditions (323 K temperature, 10 MPa pore pressure, 5 MPa effective stress) in-situ at high resolutions (3.43 μm and 1.25 μm voxel size) in 3D with an x-ray micro-computed tomograph; and measured the changes in nano-scale mechanical properties induced by acid exposure. Indeed the carbonate rock matrix partially dissolved, and absolute and effective porosity and permeability significantly increased. This dissolution was confined to the original flow channels and inlet points. Importantly, the rock matrix weakened significantly (- 47% in indentation modulus) due to the acid exposure.

    更新日期:2017-12-14
  • Feasible ionic liquid-amine hybrid solvents for carbon dioxide capture
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-10-02
    Lingdi Cao, Jubao Gao, Shaojuan Zeng, Haifeng Dong, Hongshuai Gao, Xiangping Zhang, Junhua Huang

    Ionic liquid (IL)-amine hybrid solvents have been proved to be an energy-saving system for CO2 capture. Lack of experimental information on the diffusivity and heat of CO2 absorption in IL-amine hybrid solvents hampers the wide application of IL in CO2 capture. In this work, the effects of IL on absorption rate, solubility, diffusivity and heat of CO2 absorption in feasible hybrids of 1-butyl-3-methyl-imidazolium nitrate ([Bmim][NO3]) and monoethanolamine (MEA) have been elaborated using weight method, vapor liquid equilibrium and calorimetric measurement. The results showed that the addition of IL slightly decreases CO2 loading under atmospheric pressure. Based on the measured solubility and calorimeter results, IL is beneficial to improve the physical absorption of CO2 and reduce the heat of absorption in IL-amine hybrids. The diffusivity of CO2 can be maintained at an acceptable level by controlling the concentration of IL. Considering CO2 capacity, kinetics and heat of absorption, the hybrids of 30% MEA + 10% [Bmim][NO3] + 60% H2O were recommended. Our work gives the meaningful insights on designing novel IL-amine hybrids for CO2 capture.

    更新日期:2017-12-14
  • Cost-effective architecture of carbon capture and storage (CCS) grid in India
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-10-06
    Amit Garg, P.R. Shukla, Shrutika Parihar, Udayan Singh, Bhushan Kankal

    Various modeling studies analyzing global 2 °C climate stabilization scenarios have projected penetration of CO2 capture and storage (CCS) technologies in India alongside a sizable penetration of renewable energy technologies. The assessments of geological storage potential over India have shown wide variation across regions. This paper examines the locations of large point sources of CO2 emissions in India and matches it with carbon storage locations to minimize the cost of CCS evolving grid. The concept of weighted Euclidean distance and Integrated Environmental Control Model are used to propose suitable pipeline networks for emissions-intensive clusters to optimize the cost of CO2 avoidance. The computational method estimates proximate storage location for each CO2 emitting source taking into account the total storage potential at each location. CCS requirement in India would vary depending on the global climate stabilization target. We examine two targets for India that correspond to 2 °C and well below 2 °C global mitigation regimes. According to our estimates, India could mitigate around 780 Mt CO2 per year below 60 $/t-CO2 (2005 prices) over 30 years, and another 250 Mt CO2 per year for up to 75 $/t-CO2 prices through CCS under these scenarios respectively.

    更新日期:2017-12-14
  • Heterogeneity, pore pressure, and injectate chemistry: Control measures for geologic carbon storage
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 
    Thomas Dewers, Peter Eichhubl, Ben Ganis, Steven Gomez, Jason Heath, Mohamad Jammoul, Peter Kobos, Ruijie Liu, Jonathan Major, Ed Matteo, Pania Newell, Alex Rinehart, Steven Sobolik, John Stormont, Mahmoud Reda Taha, Mary Wheeler, Deandra White

    Desirable outcomes for geologic carbon storage include maximizing storage efficiency, preserving injectivity, and avoiding unwanted consequences such as caprock or wellbore leakage or induced seismicity during and post injection. To achieve these outcomes, three control measures are evident including pore pressure, injectate chemistry, and knowledge and prudent use of geologic heterogeneity. Field, experimental, and modeling examples are presented that demonstrate controllable GCS via these three measures. Observed changes in reservoir response accompanying CO2 injection at the Cranfield (Mississippi, USA) site, along with lab testing, show potential for use of injectate chemistry as a means to alter fracture permeability (with concomitant improvements for sweep and storage efficiency). Further control of reservoir sweep attends brine extraction from reservoirs, with benefit for pressure control, mitigation of reservoir and wellbore damage, and water use. State-of-the-art validated models predict the extent of damage and deformation associated with pore pressure hazards in reservoirs, timing and location of networks of fractures, and development of localized leakage pathways. Experimentally validated geomechanics models show where wellbore failure is likely to occur during injection, and efficiency of repair methods. Use of heterogeneity as a control measure includes where best to inject, and where to avoid attempts at storage. An example is use of waste zones or leaky seals to both reduce pore pressure hazards and enhance residual CO2 trapping.

    更新日期:2017-12-07
  • Investigation of various process parameters on the solubility of carbon dioxide in phosphonium-based deep eutectic solvents and their aqueous mixtures: Experimental and modeling
    Int. J. Greenh. Gas. Con. (IF 3.741) Pub Date : 2017-10-10
    Hosein Ghaedi, Muhammad Ayoub, Suriati Sufian, Ghulam Murshid, Sarah Farrukh, Azmi Mohd Shariff

    This research presents the application of predictive regression model such as quadratic regression for estimation of CO2 solubility in deep eutectic solvents namely allyltriphenylphosphonium bromide-triethylene glycol (ATPPB-TEG) into different molar ratios and their aqueous solutions. In doing so, a design of experiment (DOE) was applied based on Taguchi L18 orthogonal array method. Four factors, namely pressure, temperature, molar ratio and water/DES concentration in mixture were selected as input parameters of model. The output parameter of model was the CO2 solubility in terms of mole fraction of CO2 (XCO2). A quadratic regression model was developed after validation and confirmation through several strong approaches. The results disclose that the prediction of developed quadratic regression model is in acceptable agreement with experimental solubility data. The overall R-squared (R2) and absolute relative error (ARE) values of proposed quadratic regression model were 0.9966 and 0.0725, respectively. Moreover, analysis of variance (ANOVA) indicates that pressure is the most significant factor influencing the XCO2. Finally, the signal to noise (S/N) ratio shows that the highest levels for pressure, concentration of DES in mixture, and molar ratio, and lowest level for temperature are the optimal levels of input parameters to obtain the highest CO2 solubility in this system. The developed quadratic regression model and correlation are effective and provide quick, reliable and accurate predictions of CO2 solubility in DESs without carrying out any time consuming, difficult and expensive experimental measurements. To the best of our knowledge, this is the first time a regression model was developed for prediction of CO2 solubility in DESs and their aqueous solutions.

    更新日期:2017-12-07
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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