The impact of downstream processing methods on the yield and physiochemical properties of hydrothermal liquefaction bio-oil Fuel Process. Technol. (IF 3.956) Pub Date : 2018-07-12 Jie Yang, Quan (Sophia) He, Kenneth Corscadden, Haibo Niu
Hydrothermal liquefaction (HTL) is considered as a promising thermochemical conversion technology for crude bio-oil (biocrude) production from biomass. However, the influence of downstream processing methods (such as biocrude recovery methods and solvents used) has not been investigated fully to date. In this investigation we examined the effect of solvents and extraction methods on the yield and physiochemical properties of biocrude from Chlorella sp. (C. sp.), spent coffee grounds (SCG), and a mixture of the two. It was found that the extraction method did not have a significant effect on the yield and physiochemical properties of biocrude derived from the feedstock of interest in this study. However, the solvents used for biocrude recovery had crucial effects, in which dichloromethane (DCM) was determined to the most favorable one from biocrude yield and chemical yield perspective. It was also noticed that the synergetic effects claimed for co-liquefaction of C. sp. and SCG were highly dependent on the solvent used to recover bio-crude. Overall, it is expected that this study could attract more attention on the impact of various recovery procedures on the yield/physiochemical properties of bio-oil resulting from hydrothermal liquefaction processes.
A new catalyst of Co/La2O3-doped La4Ga2O9 for direct ethanol synthesis from syngas Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-20 Qilei Yang, Ang Cao, Na Kang, Kang An, Zhao-Tie Liu, Yuan Liu
Kinetics of n-butanol oxidation over Pt/ZSM-5 catalyst Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-30 Weijuan Yang, Xing Zhang, Jiale Su, Yefeng Wang, Qingchen Zhao, Junhu Zhou
Direct synthesis of hierarchical SAPO-11 molecular sieve with enhanced hydroisomerization performance Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-23 Ping Zhang, Haiyan Liu, Yuanyuan Yue, Haibo Zhu, Xiaojun Bao
Assessment of spontaneous combustion status of coal based on relationships between oxygen consumption and gaseous product emissions Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-22 Junfeng Wang, Yulong Zhang, Sheng Xue, Jianming Wu, Yibo Tang, Liping Chang
It is imperative to have an in-depth understanding of the relationship between oxygen consumption and gaseous product emissions during coal self-heating not only for preventing fires in the coal industry but also for reducing emissions of hazardous gases. Two typical coal samples with high tendency of spontaneous combustion were heated to 230 °C with a programmed temperature of 1.0 K min−1 using a pilot-scale test apparatus. The trends for oxygen consumption and gaseous product emissions were obtained from continuous measurements of the gas samples at the reactor outlet via a gas chromatography equipped with a Flame Photometric Detector. Based on the rates of oxygen consumption and gaseous product emissions, the relationship between oxygen consumption and each gaseous product emission was studied. Multi-linear regressions of the oxygen consumption and gaseous product emissions were performed. The coefficients for the emission rates of CO2, CO and H2 in the regression equations of the two coals with three different particle sizes are found to be all positive, while the coefficients for the CH4 emission rates are all negative. These results indicate that the oxygen consumption of coal facilitates the release of CO2, CO and H2, while the increase of oxygen consumption rate may not enhance the release of hydrocarbon gas. Based on the results, an evaluation index defined as the ratio of oxygen consumption rate to the gaseous product emission rate is proposed to assess the state of coal spontaneous combustion.
Effects of synergy between Cr2O3 and hierarchical HZSM-5 on transformation of LPG toward propylene and ethylene Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-21 Kangzhou Wang, Subing Fan, Jianli Zhang, Qingxiang Ma, Wen Zhang, Tian-Sheng Zhao
Effect of sodium in brown coal ash transformations and slagging behaviour under gasification conditions Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-29 Alexander Y. Ilyushechkin, San Shwe Hla, Xiaodong Chen, Daniel G. Roberts
Alkali species in coal play an important role in mineral matter reactions during gasification. Brown coal ashes can be high in sodium (up to 20 wt%), which interacts with other minerals to significantly affect the formation of slag (liquid phase). At high temperatures, sodium in slag affects phase equilibria, liquidus temperature, and slag viscosity. We investigated phase transformations in brown coal ashes at 800–1000 °C and slags at 1200–1600 °C to study the behaviour of sodium species in the range of 3–15 wt% using X-ray powder diffraction, thermogravimetric analysis and electron probe microanalysis. Sodium species appeared in coal ashes in different forms, such as sulfates, carbonates, and alumina-silicates, resulting in different ash bulk compositions. After processing under gasification conditions, alkaline species react with other minerals and may result in the appearance of a liquid phase. In this study, the liquid-phase content of ashes generally increased with increasing sodium concentration. In slags, sodium often decreased the liquidus temperature and solids content below liquidus temperature. It results lower slag viscosity in sodium enriched slags. These findings demonstrate the importance of phase transformations in brown coal mineral matter during gasification, and the potential they have to strongly affect the required operational conditions.
Single step conversion of methane to methanol assisted by nonthermal plasma Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-18 Piu Chawdhury, Debjyoti Ray, Ch. Subrahmanyam
Design and operation of a low cost bio-oil fast pyrolysis from sugarcane bagasse on circulating fluidized bed reactor in a pilot plant Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-17 Wasakorn Treedet, Ratchaphon Suntivarakorn
This article presents a design study and the development of a low-cost production process for obtaining bio-oil from sugarcane bagasse by using a Circulating Fluidized Bed reactor (CFBr). The reactor had a diameter of 4 in. and a height of 4.5 m. In addition, sand with a diameter of 249 μm was used as the bed material. Sugarcane bagasse was used as the raw material for the bio-oil production. This bio-oil production system had a feed rate of between 18 and 45 kg/h. The outstanding design of this system consisted of the production of a bio-oil with high efficiency by using the following: (1) a gas combustor used in gas turbine engine, (2) a non-condensable gas recovery for use in the process, and (3) a feeder and pre-heat exchanger before condenser unit. The experiment was performed at a superficial velocity of between 5 and 7 m/s, with a bed temperature ranging from 440 to 520 °C, and with a bed inventory at 0.5 and 4.5 kg. From the experiment, it was found that this system could produce a maximum yield of bio-oil of 78.07 wt% at the bed temperature of at 480 °C. In addition, the superficial velocity, the bed inventory, and feed rate were 7 m/s, 4.5 kg, and 30 kg/h, respectively. The properties of the bio-oil, such as its heating value, viscosity, density, and pH were measured at 18,483 kJ/kg, 24.54 cSt, 1274 kg/m3, and 2.4, respectively. The chemical components of bio-oil were also investigated by GC–MS. In this system, the cold efficiency and total energy conversion to bio-oil production were 46.06% and 32.94%, respectively. From a cost analysis of bio-oil production, the results showed that the cost production was 0.353 $/l. In addition, the results revealed that the bed temperature, the solid re-circulating rate, and the suspension density had significantly and directly affected the yield of bio-oil production. Furthermore, the oxygen in the exhaust gas from the combustion system and the non-condensable gas from the process had been shown to have a direct effect upon the properties of the bio-oil.
The impact of biofuel properties on emissions and performances of a micro gas turbine using combustion vibrations detection Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-15 C. Allouis, A. Amoresano, R. Capasso, G. Langella, V. Niola, G. Quaremba
The use of pure vegetable oils in Micro Gas Turbine can damage the injection system or the combustion chamber causing undesired vibrations. An ideal solution would consist in having an available tool able to forecast and/or follow in real time the vibrational state of the combustion device. The present paper describes tests performed on a low emission Micro Gas Turbine for power generation, fueled with different liquid fuels, including commercial diesel oil and its blends with pure rapeseed oil. A particular attention was paid both on the emissions and on the measurements of the micro vibrational distributions and their correlation under the different fueling conditions using a new signal processing based on a nonlinear method and chaos analysis. We observed that the overall behavior of the MGT fueled with the blends was good, and the emission concentrations of CO, NOx and Total Particle Matter were comparable to the pure diesel oil ones. Moreover, the chaos analysis and the proposed methodology came out as a possible tool for the real-time characterization of the combustion process of the MGT and to individuation of the fuel supplied.
The effect of carbon dioxide partial pressure on the gasification rate and pore development of Highveld coal chars at elevated pressures Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-15 Saartjie M. Gouws, Hein W.J.P. Neomagus, Daniel G. Roberts, John R. Bunt, Ray C. Everson
Char structural changes occurring during gasification are normally only related to conversion and few data is published on the effect of carbon dioxide partial pressure on the extent of pore development. In this study, the char–CO2 reactivity and consequential pore development of different Highveld coal chars were investigated over a wide pressure range. Reactivity experiments were performed in a fixed bed reactor under reaction controlled conditions. The initial reaction rate was found to be solely a function of temperature and CO2 partial pressure and was well described by the Langmuir Hinshelwood rate equation. Surface analyses were performed on fresh and partially converted chars to quantify the effect of CO2 partial pressure on pore development. It was found that pores development more rapidly with conversion if the CO2 partial pressure is increased. This outcome has fundamental implications for the interpretations of gasification reaction kinetics. The term describing the total amount of active sites in the Langmuir Hinshelwood equation might not be constant at all partial pressures, and the possible impact of that is shown in this work. More work is required to further understand these effects and incorporate them appropriately into high pressure rate equations.
Correlation between bond structures and volatile composition of Jining bituminous coal during fast pyrolysis Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-30 Bin Tian, Yingyun Qiao, Xiongchao Lin, Yuan Jiang, Long Xu, Xiaoxun Ma, Yuanyu Tian
Volatile compositions of coals during fast pyrolysis are principally governed by their bond structures and establishing the relationships between them is vital for deep understanding the pyrolysis mechanism. The structural features and bond information of Jining bituminous coal (JBC) were evaluated first by the combined advanced analytical tools. Subsequently, thermogravimetry coupled with pyrolysis-gas chromatography/time of flight mass spectrometry analysis were used to capture pyrolysis behavior and volatile species of JBC. The results showed that CO bond containing species were rich in JBC and mainly in the form of aryl ethers. Therefore, phenolic compounds were the most abundant species in volatiles during fast pyrolysis and C6C9 phenols were the major constituent of this group. Average number of aromatic rings per cluster, number of substituents on each aromatic ring, and length of methylene chain in JBC were 3, 3–4, and 1.36, respectively. However, the three parameters calculated from the aryl-containing species in volatiles were all smaller than those of JBC. Cleavages of CalO, CalCal, CarCal, and CarO greatly contributed to volatile release and 67% of the mass loss during pyrolysis of JBC was caused by breakage of aliphatic CC and CH. Furthermore, pyrrolic nitrogen was found to be the most abundant form of organically bound nitrogen, but the pyrolysis volatiles contained more pyridine-N.
Experimental study on non-vaporizing spray characteristics of biodiesel-blended gasoline fuel in a constant volume chamber Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-28 Shubhra Kanti Das, Kihyun Kim, Ocktaeck Lim
Experimental study on the inhibitory effect of ethylenediaminetetraacetic acid (EDTA) on coal spontaneous combustion Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-14 Jinhu Li, Zenghua Li, Chaojie Wang, Yongliang Yang, Xiaoyan Zhang
The inorganic salts in coal contain a certain number of metal ions, among which transition metal ions can exert a certain catalytic effect on coal spontaneous combustion by reducing the activation energy of coal oxygen reaction. Therefore, the addition of metal chelating agent in coal will definitely reduce the catalytic effect of metal ions, so as to inhibit coal spontaneous combustion. In this paper, the inhibitory effect of a common metal chelating agent ethylenediaminetetraacetic acid (EDTA) on coal spontaneous combustion was studied. Four coal samples were selected in this study. First, basic data such as the types and contents of transition metal elements in coal samples were measured via X-ray fluorescence (XRF). Then, thermal analyses, infrared spectrum experiments, low-temperature oxidation experiments and crossing point temperature experiments were performed on WL coal samples before and after EDTA treatment. The experimental results show that there is no mass gain caused by oxygen adsorption in the EDTA-treated coal sample throughout the heating process. In addition, the treated coal sample exhibit a great reduction in its content of oxygen functional groups, a decrease in the concentration of gas products and a rise of the crossing point temperature, indicating that EDTA has a strong inhibitory effect on coal. The calculation of the apparent activation energy reveals that the activation energies of the inhibited coal sample were 51.18 kJ/mol and 43.42 kJ/mol in the temperature ranges of 30–70 °C and 80–180 °C, respectively, which are 7.94 kJ/mol and 8.28 kJ/mol higher than those of the raw coal. This proves that the metal chelating agent EDTA is able to inhibit coal spontaneous combustion by chelating transition metal ions to increase the activation energy. Finally, experiments were carried out to study the inhibitory effects of EDTA on different coal samples, which suggests that EDTA can exert good inhibitory effects on different coal samples.
A study on catalytic hydrogen production: Thermodynamic and experimental analysis of serial OSR-PROX system Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-13 Melek Selcen Başar, Burcu Selen Çağlayan, A. Erhan Aksoylu
Study on the effects of carrier and modifier on mercury adsorption behavior over halides modified sorbents using temperature programmed desorption method Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-14 Yang Xu, Xiaobo Zeng, Guangqian Luo, Yongqing Xu, Xian Li, Hong Yao
Halides modified sorbents injection equipped with dust removal units is considered as the most promising technology for elemental mercury (Hg0) removal from coal-fired flue gas. However, Hg0 adsorption behavior over different halides modified sorbents remains controversial. In this study, the effects of carriers (activated carbon and neutral Al2O3) and modifiers (NaCl, NaBr, CuCl2, and CuBr2) on the behavior of Hg0 adsorption over modified sorbents were investigated using temperature programmed desorption (TPD) method. Both mercury adsorption experiments and TPD experiments were conducted in the bench-scale fixed bed. The results indicated that CuBr2-modified activated carbon (AC) showed the best mercury removal performance due to the lower bond energy of CuBr2. The decomposition temperature of mercury compounds generated on AC was different from that on neutral Al2O3. Further analysis indicated that the modifiers with lower bond energy could release halogens during modification. The released halogens could react with AC to form active CCl or CBr group. Moreover, the lower bond energy of modifiers made it easier for halogens to release. But Al2O3 carrier could not react with modifiers to form active group during modification. The Hg0 adsorption process over modified Al2O3 could be explained by Langmuir-Hinshelwood mechanism.
Investigation into enhancing reforming of biomass-derived glycerol in a membrane reactor with hydrogen separation Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-14 Shuai Wang, Xuesong Yang, Shaodong Xu, Bowen Li
In order to investigate the hydrogen separation enhancing effect on glycerol steam reforming performance, the simulation is carried out via a packed bed membrane reactor, where the porous media model is employed to model the distribution of catalyst and the non-isothermal environment in the reactor is considered. The reforming performances with and without membranes are compared. The results indicate that the membrane separation can promote the hydrogen production at a low temperature. The impacts of operating parameters including catalyst load, fuel gas temperature, sweep gas velocity and sweep gas temperature on the enhancement of the reforming performance are analyzed. The results reveal that the membrane separation is very sensitive to the temperature variation under different operating conditions. It is essential to properly control the operating parameter so as to achieve the promotion of hydrogen yield with low cost of energy.
Measuring residence time distributions of wood chips in a screw conveyor reactor Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-14 Charles Chamberlin, David Carter, Arne Jacobson
In rotating screw conveyors both the average and the distribution of the residence time influence the extent and the uniformity of the transformation. Experimenters have applied two distinct experimental approaches to obtain the residence time distribution of granular solids in longitudinal reactors: 1) measuring the mass flow rate of product at the exit from the reactor in response to a step change (either positive or negative) in the mass flow rate of feedstock into the reactor or 2) measuring the appearance of a tracer in the flow exiting the reactor in response to either a pulse or a step change addition of tracer in the inlet. We found that all three methods reveal residence time distributions that are approximately normal (i.e., symmetrical and bell-shaped), but the distribution estimated from the pulse input of tracer exhibited a long trailing tail that was not detectable in either the positive or negative step changes. Second, we demonstrated that a normal probability plot proved valuable in displaying and analyzing the residence time distribution obtained by the pulse addition of tracer. Finally, we observed that all three methods yielded mean residence times that consistently differed from the nominal values. The positive step change averaged 8% shorter, the pulse addition of tracer averaged 7% longer, and the negative step change averaged 60% longer.
Rare earth salt of 12-tungstophosphoric acid supported on iron oxide as a catalyst for selective catalytic reduction of NOx Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-06 Ying Wei, Yongliang Chen, Rui Wang
Catalytic upgrading of biomass-derived vapors on carbon aerogel-supported Ni: Effect of temperature, metal cluster size and catalyst-to-biomass ratio Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-06 Luis E. Arteaga-Pérez, Romel Jiménez, Nicolas Grob, Oscar Gómez, Romina Romero, Frederik Ronsse
A comprehensive study of carbon aerogel-supported nickel (Ni/CAG) in the catalytic fast pyrolysis (CFP) of torrefied Eucalyptus globulus was performed in a micropyrolysis unit (Py-GCMS). Effects of pyrolysis temperatures (450–600 °C), catalyst-to-biomass ratio (1:1 < C-to-B < 10:1) and metal cluster sizes (9.6 < Dpi < 21) on upgrading reactions were analyzed. Catalysts were characterized by N2 adsorption-desorption at 77 K, X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). Regardless the use of catalysts, the pyrolysis vapors produced from torrefied biomass were depleted in carboxylic acids (selectivity < 7%). Furthermore, the CFP decreased the selectivity to furans and ketones by almost 50%, while phenols increased in a similar proportion. Despite the similarities in the selectivity distribution of these functional groups in all the CFP experiments, their internal composition was rather different owing to the changes in temperature, C-to-B ratio and catalyst cluster sizes. Ni/CAG was active for hydrogenation under H2-depleted atmosphere, presumably by a synergistic effect between water gas shift and reforming reactions with transalkylation and decarbonylation of phenolics and furanics. It was demonstrated that metal cluster sizes influenced the reaction routes by favoring hydrogenation on metal facets and deoxygenation on step/corners sites.
Mn-based oxygen carriers prepared by impregnation for Chemical Looping Combustion with diverse fuels Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-02 T.R. Costa, P. Gayán, A. Abad, F. García-Labiano, L.F. de Diego, D.M.A. Melo, J. Adánez
Chemical Looping Combustion (CLC) is considered one of the low cost alternatives for CO2 capture for fossil fuels combustion and to reach negative emissions through biomass CLC. The cornerstone of the CLC process is the oxygen carrier performance that represents the main additional cost with respect to the conventional combustion. Manganese-based oxygen carriers are subjected to a growing interest because they are low cost, not toxic and environmentally friendly. In this work five impregnated oxygen carriers, with manganese oxide Mn3O4 or Mg6MnO8 as their active phase and three commercial supports based on zirconia and synthetic calcium aluminate, were prepared. Their behaviour for CLC was examined by TGA, batch fluidized bed reactor, TPR, SEM-EDX and XRD. After a preliminary screening two carriers (Mn-ZrM and Mn-ZrSG) were subjected to multiple redox cycles by TGA and batch fluidized bed reactor. Both showed high solids conversion by TGA under the tested conditions, appropriated resistance to fracture, rate indexes relatively high, although Mn-ZrM showed agglomeration and deactivation during batch fluidized bed tests. Reactivity in batch fluidized bed reactor of the Mn-ZrSG oxygen carrier with methane increases with temperature although suffered from significant deactivation. This was different to the results found during multiple redox cycles by TGA. There was not a clear reason for this decrease in the reactivity that likely could be due to the uncomplete oxidation in the batch fluidized bed reactor, although further investigations are needed. On the other hand, it presented high and constant reactivity with CO and H2 in all the range of temperatures tested, being suitable for iG-CLC processes of coal or biomass and syngas combustion. Agglomeration problems were not found and the attrition losses were small. Calculated lifetime was around 11,000 h, much higher than any other Mn-based material developed or tested for CLC.
Oxidative pyrolysis of pine wood, wheat straw and miscanthus pellets in a fixed bed Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-01 Xuan-Huynh Pham, Bruno Piriou, Sylvain Salvador, Jeremy Valette, Laurent Van de Steene
Oxidative pyrolysis is a key step in the autothermal operation of many fixed-bed reactors for staged gasification and advanced carbonisation. In these reactors, biomass is converted into charcoal, condensates and permanent gases inside a moving Oxidation Zone (OZ) which also produces energy to self-sustain the process. Oxidative pyrolysis of three different biomass types: pine wood, miscanthus and wheat straw pellets, was performed in a batch 20 cm diameter fixed bed reactor. Results showed that the OZ consumed 11% to 14% of the stoichiometric air to self-sustain the process and reached a peak temperature around 720 °C whatever the biomass. The propagation velocity and thickness of the OZ were inversely proportional to the ash content and to the bulk density of the biomass. Ash was also shown to influence the yield and composition of the resulting products due to a catalytic effect on primary and secondary pyrolysis reactions.
Experiments and modeling of single plastic particle conversion in suspension Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-01 Mohammadhadi Nakhaei, Hao Wu, Damien Grévain, Lars Skaarup Jensen, Peter Glarborg, Sønnik Clausen, Kim Dam–Johansen
Conversion of single high density polyethylene (PE) particles has been studied by experiments and modeling. The experiments were carried out in a single particle combustor for five different shapes and masses of particles at temperature conditions of 900 and 1100°C. Each experiment was recorded using a camera. For selected experiments, the center and surface temperatures of the particles were measured using a thermocouple and an IR camera, respectively. During each experiment, the polyethylene particles went through melting, deformation, and decomposition. After the start of decomposition, the surface temperature became almost constant within the range of 480–550°C. The total conversion times of polyethylene particles were mainly influenced by the reactor temperature and particle mass, and the effect of particle shape was less significant. A non–isothermal 1D model was established and validated against the experiments as well as literature data. Furthermore, a simplified isothermal model appropriate for CFD applications was developed, in order to model the combustion of plastic particles in cement calciners. By comparing predictions with the isothermal and the non–isothermal models under typical calciner conditions, it is shown that the accuracy in prediction of the total conversion times of thermoplastic particles is within ± 30%, for particles lighter than 1000 mg.
Sulfonate based zwitterions: A new class of extractants for separating phenols from oils with high efficiency via forming deep eutectic solvents Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-01 Congfei Yao, Yucui Hou, Shuhang Ren, Weize Wu, Youan Ji, Hui Liu
To develop a greener method to separate phenols from oils, four kinds of halogen-free zwitterions, including 1-(propyl-3-sulfonate)-triethylaminium (TEA-PS), 1-(propyl-3-sulfonate)-tripropylaminium (TPA-PS), 1-(butyl-4-sulfonate)-triethylaminium (TEA-BS) and 1-(butyl-4-sulfonate)-tripropylaminium (TPA-BS), were designed and synthesized to separate phenols from model oils via forming deep eutectic solvents (DESs) based on the formation of hydrogen bonding between OH group on phenol and the oxygen atom on SO3− group of the zwitterions. The effects of time, temperature, dosage of zwitterions, initial phenol content, and structure of zwitterions were investigated. The results show that the extraction process can reach equilibrium within 2 min and the extraction efficiency is not sensitive to temperature. The zwitterions separate well phenol from model oils at room temperature, and the minimum phenol contents follow the order: TEA-PS > TPA-PS > TEA-BS > TPA-BS. The minimum phenol content and the maximum extraction efficiency at 25 °C can reach 4.8 g dm−3 and 98.6%, respectively, by using TPA-BS. All the maximum extraction efficiency can be obtained with nzwitterions:nphenol of less than 0.4, which greatly reduces the dosages of extractants. Importantly, these zwitterions can avoid the introduction of halide ion, which can seriously corrode the process equipment. All these zwitterions can be easily regenerated by an anti-solvent method without an obvious mass loss and a decrease in phenol extraction efficiency. Lastly, the extraction mechanism was studied with FT-IR and the freezing points of DESs indicate that the DESs are formed through hydrogen bonding.
Pyrolysis simulations of Fugu coal by large-scale ReaxFF molecular dynamics Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-01 Mingjie Gao, Xiaoxia Li, Li Guo
This paper presents pyrolysis simulations of a multi-component structure model of Fugu sub-bituminous coal containing 23,898 atoms with ReaxFF MD. The slow heat-up and long-time isothermal simulations were performed using the GPU-enabled ReaxFF MD code of GMD-Reax and reaction analysis code of VARxMD. The simulated pyrolyzate evolution trends and pyrolysis stages proposed based on lumped pyrolyzates agree fairly with literature. Major reaction pathways for early generation of CO2, H2O, CH4 and H2 in the activation and primary pyrolysis stages are found closely associated with carboxyl and methoxyl groups, indicating the significant role of oxygen-containing groups in the initialization of Fugu coal pyrolysis. Compared with reported experiments, the coal tar yield is over-predicted, while the gas yield is slightly under-estimated. To shorten the simulation time from 2 ns to 250 ps, an increase of 400 K in average on the basis of temperature range of 1200–2200 K is needed that will result in the over-prediction for the yields of gas and tar, as well as under-prediction for the non-volatile yield. This work suggests that ReaxFF MD simulation is useful for revealing the overall scenario and detailed reactions in coal pyrolysis but cautions should be taken for proper elevated temperatures.
Industrial stress-test of a magnetic resonance moisture meter for woody biomass in southern European conditions Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-01 Giovanni Aminti, Alessandro Cinotti, Carolina Lombardini, Raffaele Spinelli, Gianni Picchi
Moisture content (MC) is the most important quality parameter for energy wood. Unfortunately, checking MC under operational conditions is difficult, because the standard method for MC measurement requires up to 48 h. The bioenergy industry needs alternative methods allowing fast and reliable MC determination, but most of the commercial devices require biomass-specific calibration models. This is an important limitation, particularly in Mediterranean areas, where mixed forest dominate and feedstock loads can include multiple species. In this study a moisture meters based on Magnetic Resonance (MR) was tested for assessing its reliability as an alternative to oven drying. For this purpose, a stress-test was performed at the premises of an energy facility in Southern Italy, using a commercial MR analyzer. Thanks to the non-destructive action on the biomass of MR technology, the MC of 350 samples was measured with both MR and standard gravimetric techniques. Results confirm the validity of the MR analyzer as an alternative to oven drying. Accuracy and precision of the machine are both satisfactory, with over 95% of values within ±2.5% of deviation and a Standard Error of Performance of 1.2%. Furthermore, the analyzer processes over 15 samples per hour, coping with frequent deliveries.
Experimental study and modeling of heavy tar steam reforming Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-01 Qiang Li, Qian Wang, Anchan Kayamori, Jiansheng Zhang
In this paper, the elimination of heavy tar by steam reforming at high temperature was studied with experiments and numerical simulation. The experiments were conducted in a tube reactor with five model compounds at temperatures of 1273–1673 K, steam of 0–40 vol% and sample weight of 3–20 mg with residence time of 2 s. The simulation was performed with the plug flow model in CHEMKIN program based on a kinetic model that consists of >200 chemical species and 2000 elementary step-like reactions. The results of experiments indicate that increasing temperature will accelerate the decomposition of heavy tar; moisture could significantly prompt the decomposition of heavy tars, but not so efficient above 20 vol%; less sample could help the decomposition of heavy tar; longer residence time can slightly increase the decomposition of heavy tar. At high temperature (1573 K or above), the heavy tar is mainly cracked into two parts: the one carbon molecules (CO and CO2) and the soot at the beginning of reactor. Then the soot decomposes into CO, CO2 and H2 by steam reforming. The conversion and kinetic data of heavy tar can be divided by two temperature sections. The carbon conversion degrees of different model compounds from 1173 K to1473 K are close with similar trends, which may be represented by a universal kinetic model. Our results provide an insight in the understanding of the heavy tar decomposition and give the necessary information for the designation and operation of the tar cracker to eliminate heavy tar.
Cold plasma dielectric barrier discharge reactor for dry reforming of methane over Ni/ɤ-Al2O3-MgO nanocomposite Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-01 Asif Hussain Khoja, Muhammad Tahir, Nor Aishah Saidina Amin
Reduction of mild-dehydrated, low-grade iron ore by ethanol Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-31 Ade Kurniawan, Keisuke Abe, Kouichi Ohashi, Takahiro Nomura, Tomohiro Akiyama
Low-grade iron ore with high combined water (CW) content (e.g., goethite) has been first dehydrated at low temperatures mildly to be slit-shaped nano-order pore, then has been reduced by ethanol (C2H5OH) charging under the heating conditions. Bioethanol as derived from biomass, regarded as a renewable and carbon-neutral resource, is a promising candidate as a reducing agent for ironmaking. In the experiments, ethanol was dropwise added to the mild-dehydrated, porous iron ore beds at heating conditions using the temperature-program. As a result, the ethanol was soon decomposed to CO and H2, which then reduced the iron oxides. Porous iron ore acts as a good catalyst for ethanol decomposition as it simultaneously reduces to metallic iron. Interestingly, iron oxides were reduced at a lower temperature, compared to conventional coal-based ironmaking in the blast furnace. Metallic Fe was obtained at only 750 °C, showing a reduction degree of 81%, due to the contribution of hydrogen reduction. The longer charging time of ethanol promotes the higher reduction degree as well as sufficient compositions of reducing gas (H2-CO) for the reduction process. The results of experiments using different iron ores revealed the general rule that the higher CW content in ore makes the larger surface area of the iron ore by mild-dehydration, causing higher reactivity in the reduction process. The results appealed that mild-dehydrated iron ore is good raw materials of bioethanol ironmaking, due to its nanopores.
Effect of Al-containing precursors on Cu/ZnO/Al2O3 catalyst for methanol production Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-30 Fan Zhang, Yuan Liu, Xiaoying Xu, Panpan Yang, Ping Miao, Yulong Zhang, Qi Sun
Aluminum is an essential ingredient in the ternary Cu/ZnO/Al2O3 catalyst for methanol synthesis from syngas. This work investigated the effect of Al-containing precursors on Cu/ZnO/Al2O3 catalysts during catalyst preparation. A series of Cu0.6Zn0.3Al0.1 catalysts with various Al-containing precursors, including Cu-Zn-Al hydrotalcite, aluminum hydroxide and Zn-Al hydrotalcite, were prepared by co-precipitation and fractional-precipitation, respectively. The catalysts were characterized with XRD, TG, XRF, N2 physisorption, N2O chemisorption, SEM, TEM/EDS and TPR. Results show that the Al-containing precursor has an important effect on the Cu substitution by Zn in malachite lattice, leading to various performances of the obtained catalysts. The catalyst with Al existing as aluminum hydroxide performed high Cu substitution in the co-precipitated zinc malachite, and exhibits better catalyst performance compared to its counterparts. Aluminum hydroxide can be a suitable Al-containing precursor for preparing the Cu/Zn/Al methanol-synthesis catalyst.
Structure, electrical conductivity, and dielectric properties of semi-coke derived from microwave-pyrolyzed low-rank coal Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-30 Shuqin Liu, Yanjun Zhang, Kaiyong Tuo, Liping Wang, Gang Chen
A study was undertaken to investigate the structure, electrical conductivity and dielectric properties of low-rank coals during microwave pyrolysis. The mechanism of dielectric response during microwave pyrolysis was also discussed. The pyrolysis conditions were a microwave power of 800 W and different radiation times; dielectric properties were measured using a vector network analyzer at a frequency of 2450 MHz, and the electrical conductivity was measured using a four-probe resistivity tester. Results show that with increasing microwave radiation time, the functional groups gradually cracked and fell off, and the structural order was gradually enhanced. In addition, the order of the structure increased the number of sp2-hybridized carbon atoms on a single plane and increased the delocalized electrons between the graphite crystal planes. The complex relative permittivity and resistivity of the semi-cokes exhibited a significant dependence on microwave radiation time and pyrolysis temperature, especially after 15 min of microwave radiation. By comparing the calculated and measured values of imaginary parts, it could be deduced that the electric conductive loss is also an important part of the microwave attenuation mechanism in the process of microwave pyrolysis, as important as the relaxation loss and the interface polarization loss.
Effect of cooling rate on the reaction of volatiles from low-rank coal pyrolysis: Molecular dynamics simulations using ReaxFF Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-30 Dikun Hong, Liang Liu, Shu Zhang, Xin Guo
The secondary reactions of volatile compounds have great effects in determining the yield of products in coal pyrolysis process. While secondary reactions of volatiles under different heating conditions have been extensively investigated over the last few decades, reaction mechanism of volatiles in cooling process is still not well understood. The effect of cooling rate on the reaction of volatiles from low-rank coal pyrolysis is studied using ReaxFF molecular dynamics simulations. First, a series of coal pyrolysis simulations are carried out at different temperatures. The newly formed volatile compounds containing radical fragments are extracted from pyrolysis products to construct the model of nascent volatiles. Then, the system of volatiles is cooled down to 300 K at different cooling rates ranging from 5 to 500 K/ps. The results show that the secondary reactions of volatiles still occur even at 500 K/ps, and the amount of gas and coke increase with decreasing cooling rate. The reaction mechanisms of volatiles in cooling process are revealed by analyzing the main elementary reactions. In rapid cooling, only the agglomeration of tar fragments is observed. While, the reactions of tar in slow cooling condition undergoes two stages: agglomeration of tar fragments resulting in the formation of coke compounds, and subsequently reactions of the coke with tar fragments leading to the growth of coke weight. Finally, the activation energy for the secondary reactions of nascent tar is determined by fixed-temperature simulations from 1800 to 2800 K and is found to be 24.4 kcal/mol, which is in good agreement with recent experimental results.
Quantification of reactive intermediate radicals and their induction effect during pyrolysis of two n-alkylbenzenes Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-29 Zezhou Chen, Xurui Zhang, Zhenyu Liu, Qingya Liu, Teng Xu
Recent advances in the beneficiation of ultrafine coal particles Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-29 Guichao Wang, Xuetao Bai, Changning Wu, Weng Li, Ke Liu, Ali Kiani
Only when problems in ultrafine coal particle beneficiation process are well understood and clarified, efficient methods can be devised to recover ultrafine coal particles in an economically viable way. When minerals are fully liberated from organic substances in the grinding process, coal beneficiation methods are needed to efficiently separate organic materials from mineral ones. This is necessary for clean coal technologies as the pollutants associated with coal utilization are the key factor in limiting the sustainability of coal utilization. To assess the current state of knowledge available in this area, a comprehensive literature review on the ultrafine coal particle beneficiation techniques is carried out with main focus on recent progresses. In this paper, previous studies on the ultrafine coal beneficiation have been critically analyzed with respect to the effects of particle sizes and surface properties. The techniques are classified into two categories, physical separation (including gravity, magnetic and electrostatic separation method) and physico-chemical separation (including oil agglomeration and bubble flotation method). The aim of this paper is to review developments and limitations of current ultrafine coal particle beneficiation techniques and also to identify the future development in recovering ultrafine coal particles.
Hydrogenation of CO2 to formic acid catalyzed by heterogeneous Ru-PPh3/Al2O3 catalysts Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-28 Wenjing Zhang, Shengping Wang, Yujun Zhao, Xinbin Ma
Evolution of coke in the catalytic conversion of biomass-derivates by combined in-situ DRIFTS and ex-situ approach: Effect of functional structure Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-26 Shanshan Shao, Huiyan Zhang, Rui Xiao, Xiaohua Li, Yixi Cai
To understand the evolution of coke in the catalytic conversion of biomass-derivates, in-situ diffuse reflectance Fourier transform infrared spectroscopy experiments and ex-situ extraction method were combined to identify the coke species. Considering the ring-shape and unsaturation of furan as an important intermediate from biomass pyrolysis, other simplified biomass-derivates like tetrahydrofuran, butanol, ethylene glycol and methanol was also studied to investigate the effect of its chemical structure on coke formation. The ex-situ study showed that the performance in the induction period and deactivation stage was closely related to the functional group of biomass-derivates. Coke extraction of furan and tetrahydrofuran were of similar composition, which was of doubt. Combined results with in-situ diffuse reflectance Fourier transform infrared spectroscopy revealed that polymethyl benzaldehyde was the main composition of active coke in the catalytic conversion of furan, and then intermediate of benzofuran was detected, and finally alkyl naphthalene and polyaromatic hydrocarbons were formed by polymerization and hydrogen transfer. This study will provide guidelines to enhance hydrocarbon production from the viewpoint of active coke like pre-feeding of polymethyl benzaldehyde.
Purification of crude glycerol derived from biodiesel production process: Experimental studies and techno-economic analyses Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-26 Chol G. Chol, Ravi Dhabhai, Ajay K. Dalai, Martin Reaney
In the present work, crude glycerol was purified by a combined strategy of physicochemical treatment and semi-continuous membrane filtration using a 5 kDa ultrafiltration tubular membrane. Three parameters – temperature, pressure, and flow rate were studied to see the effect of membrane filtration on glycerol purity. A maximum glycerol purity of 93.7% was obtained from crude glycerol of 40% purity after the physicochemical treatment and membrane filtration at the temperature, pressure, and flow rate of 50 °C, 700 kPa, and 50 mL/min, respectively. Most of the purification occurred during physicochemical treatment. Techno-economic analysis based on a scenario where all the purified glycerol is converted to value added chemicals – solketal and glycerol carbonate - showed that the glycerol purification process is economically feasible. In this scenario (scenario 3), the required capital investment was $2.1 million and the net present value of the project were $6 million (with 10% discounting rate) or $3.65 million (with 15% discounting rate), respectively, over 10 years of operation after start-up with capital investment in the initial three-year period with no returns. The unit cost and revenue of crude glycerol purification was $50.85/kg and $80.36/kg, respectively, making it a promising undertaking. The results of the present work can also be useful for the purification or recovery of other valuable biodiesel by-products such as free fatty acids, soaps, and solvents.
Lower order representations of evolving particle size distributions for rapid gas-particle mass transfer simulations during electrostatic precipitation Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-24 Herek L. Clack
The range of particle sizes typically present in combustion flue gas complicates predictions of gas-particle mass transfer processes. This complexity is amplified within electrostatic precipitators where particle motion, abundance, and mass transfer characteristics are size dependent. The present study illustrates the utility of replacing explicit representations of particle size distributions in simulations of electrostatic precipitators with an equivalent loading of monodisperse aerosols of diameter chosen to reproduce the same gas-particle mass transfer characteristics. Computational times are reduced by an order of magnitude using this approach, facilitating future incorporation of multiple particle types or heterogeneous chemical kinetics.
Liquefaction of kraft lignin over the composite catalyst HTaMoO6 and Rh/C in dioxane-water system Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-18 Lele Jin, Wenzhi Li, Qiying Liu, Jindong Wang, Yuanshuai Zhu, Zhenhang Xu, Xiangqian Wei, Qi Zhang
A catalytic routine was developed for kraft lignin depolymerization in dioxane-water systems, in which the catalyst HTaMoO6 with strong Bronsted acidity and a hydrogenation catalyst (Rh/C) were employed simultaneously. The performance of the composite catalysts was tested in a series of experiments with various reaction temperatures, reaction time and catalyst ratios. Under the optimized conditions, a higher petroleum ether soluble fraction yield of 58.7% was obtained at 320 °C for 24 h. Besides, a higher liquid product yield of 95.6% was achieved at 290 °C for 2 h. Specially, the main compositions of the petroleum ether soluble fraction are monomers and dimers, which can be used as liquid fuel. These results demonstrated that the composite catalyst HTaMoO6-Rh/C can effectively catalyze the depolymerization of the kraft lignin into small molecule liquid fuel components.
Plasma-assisted catalytic conversion of NO over Cu-Fe catalysts supported on ZSM-5 and carbon nanotubes at low temperature Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-18 Tao Wang, Xinyu Zhang, Jun Liu, Hanzi Liu, Yonghong Guo, Baomin Sun
A series of Cu-Fe catalysts with fixed metal content and variable ratios of ZSM-5 and CNTs were used to investigate NO removal in a plasma-catalyst system at low temperature. The catalysts were characterized by BET, XRD, TGA, XPS, H2-TPR and NH3-TPD. The results showed that the catalyst promoted the NO conversion rate from only plasma system, and 1Z3C catalyst exhibited the best NO conversion rate of 86.1% at 191.5 J/L. Composite support promoted the catalytic activity at low temperature, and greatly improved the Cu2+ and Fe3+ concentration on the 1Z3C catalyst, both Cu2+ and Fe3+ contributed greatly to catalytic reaction of NO conversion. Chemisorbed oxygen also acted as activated sites for NO conversion. When the input energy was 75 J/L, the NO conversion rate decreased from 70% to 41% with adding 500 ppm SO2, which decreased with increasing SO2 concentration, while generation rate of SO3 was less than 0.2% in the combination system. In the presence of SO2, copper sulfate species, ferric sulfate species and ammonium sulfates generated on the surface of catalyst, which consumed Lewis acid sites and blocked the active sites, decreasing NO conversion rate.
Microwave-assisted co-pyrolysis of high ash Indian coal and rice husk: Product characterization and evidence of interactions Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-17 B. Rajasekhar Reddy, R. Vinu
In this study, microwave-assisted co-pyrolysis of high ash Indian coal and rice husk is investigated to evaluate the yield and quality of the pyrolysis oil, and to understand the interactions during co-pyrolysis. Microwave co-pyrolysis experiments were conducted in a bench scale unit, and the effects of various parameters such as microwave power (420 W and 560 W), coal:rice husk ratio, and feed:susceptor (graphite) ratio on product yields and oil composition were thoroughly evaluated. Oil yield was not significantly affected by microwave power and feed:susceptor ratio for a particular coal:rice husk ratio. The oil yields were 11 ± 2 wt%, 15 ± 2 wt%, 18 ± 2 wt%, 21 ± 2 wt% and 26 ± 2 wt% for 100:0, 75:25, 50:50, 25:75 and 0:100 wt./wt. coal:rice husk, respectively, at both microwave powers, and followed an additive effect with increase in rice husk amount in the mixtures. Pyrolysis oil contained monoaromatic hydrocarbons, naphthalene derivatives, aliphatic hydrocarbons and phenolic derivatives. The interactions between coal and rice husk pyrolysis intermediates were evidenced in the form of enhanced yields of polyaromatic hydrocarbons with a concomitant reduction in yield of methoxy phenols. Pyrolysis oil from coal had highest heating value (36–38 MJ kg−1) due to the presence of aliphatic hydrocarbons, while that from rice husk had the lowest heating value (28–30 MJ kg−1) due to high oxygenate content. The heating values of co-pyrolysis oils were in the range of 30–36 MJ kg−1. Hydrogen constituted a major fraction in the pyrolysis gases, and the addition of rice husk to coal promoted the evolution of CO.
Enhanced electrochemical performances of coal liquefaction residue derived hard carbon coated by graphene as anode materials for sodium-ion batteries Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-17 Ruifeng Liu, Yulong Li, Chunlei Wang, Nan Xiao, Lei He, Hongyi Guo, Peng Wan, Ying Zhou, Jieshan Qiu
A graphene coated coal liquefaction residue (CLR) derived hard carbon (HC@G) composite anode for sodium ion batteries was prepared by thermal annealing the mixture of the chemically modified hard carbon with graphene oxide. The irregular shaped hard carbon particles were coated uniformly by wrinkled graphene sheets. Both HC and HC@G possess large inter-layer spacing and poor porosity, but a richer pore structure that facilitating ion transport was generated after graphene coating. Because poor conductive hard carbon particles are bridged by graphene sheets, a better conductivity of HC@G is detected by voltammetry test and the EIS analysis. Graphene coating contributes little to the sodium storage capacity. However, HC@G exhibits a much better rate performance and a dramatic improvement of cycling capability with the capacity retention 83% after 2000 cycles at a high current density of 2 A·g−1. The impressing rate and cycle performances of HC@G anode are attributed to the hierarchical structure with rich ion diffusion channels and extensive electronic conduction path.
Investigating char agglomeration in blast furnace coal injection Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-24 Dane C. Sexton, Julian M. Steer, Richard Marsh, Mark Greenslade
Blast furnace iron manufacturers aim to reduce expensive coke usage through the injection of coal. This paper investigates contrasting agglomeration behaviour with a view towards optimising blast furnace operations and limiting furnace permeability issues. A drop tube furnace (DTF) was used to investigate the performance of two coal particle size specifications that were representative of injection coal sizes: pulverised (100% < 300 μm, 50% < 75 μm), and granulated (100% < 1 mm, 50% < 250 μm). A range of coals was subjected to DTF testing with issues arising from the injection of caking coals. Results show these coals exhibit signs of agglomeration, a potentially problematic effect concerning blast furnace permeability. Considering gasification reactivity upon leaving the blast furnace raceway, it was found that the agglomerated coal chars do not suffer from poor reactivity and are more reactive than the non-agglomerated chars. Pre-treatment through oxidation was found to be an effective means of eliminating agglomeration in the DTF as a result of the reduction in caking properties.
Investigating the impact of an Al-Si additive on the resistivity of biomass ashes Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-17 Lee J. Roberts, Patrick E. Mason, Jenny M. Jones, William F. Gale, Alan Williams, Connie Ellul
Ash resistivity is an important factor in the collection efficiency of electrostatic precipitators (ESPs). There is good experience in the industry regarding resistivity of coal fly ash and well-established models for its prediction based on coal ash composition. The same is not true for biomass ash and this paper reports much-needed data for three different biomass types. Coal pulverised fuel ash (PFA), can be used as an aluminosilicate additive to mitigate biomass ash deposition issues. The effects of PFA additive on the resistivity of biomass ashes is also reported here. Biomass ash resistivity is an order of magnitude lower than that of typical coal ashes, and thus re-entrainment of particles in ESPs may become an operational issue, exacerbated by the presence of moisture and sulphur. PFA additive can increase the resistivity, but also leads to higher ash loading. Regression analysis indicates that potassium in biomass ash impacts significantly upon resistivity, contrary to previous studies. Various existing resistivity models were tested for predicting biomass ash resistivity; they produced significant overestimates when compared to experimental results due to omission of potassium as a component of the ash. Modifications to existing models or new models are required to predict resistivity of biomass ashes, and the data reported here will be important for developing such a model.
Absorption of nitric oxide in simulated flue gas by a metallic functional ionic liquid Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-16 Ying Sun, Shuhang Ren, Yucui Hou, Kai Zhang, Weize Wu
Study of glycerol etherification with ethanol in fixed bed reactor under high pressure Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-16 Caroline O.T. Lemos, Leticia L. Rade, Marcos A. de S. Barrozo, Lucio Cardozo-Filho, Carla E. Hori
The aim of this work was to optimize the reaction parameters for the glycerol etherification with ethanol in a fixed bed pressurized reactor using Amberlyst 15 as a catalyst. A three factor central composite design was proposed to study the effect of reaction temperature (180–250 °C), ethanol/glycerol molar ratio (4–20/1) and amount of catalyst (0–0.80 g) over the glycerol conversion and yield of ethers. Analysis of variance (ANOVA) was used to evaluate the significance of the independent variables and their interactions. The correlations between reaction parameters and response variables were made by regression models. Among the variables screened, the reaction temperature and catalyst amount were statistically significant in glycerol conversion and ethers yield. The optimum levels of the parameters on yield of ethers were: temperature (238 °C), ethanol/glycerol molar ratio (16/1) and catalyst amount (0.61 g). Experimental verification of the predicted optimum conditions for yield of ethers gave the unprecedented response of 56%. These results indicated that the models were capable in describing the actual experimental data. Therefore, a process using a fixed bed high-pressure reactor has the potential to be used in glycerol transformation into ethers.
Simulation investigation of drying characteristics of wet filamentous biomass particles in a rotary kiln Fuel Process. Technol. (IF 3.956) Pub Date : 2018-07-07 Conghui Gu, Zhulin Yuan, Shanshan Sun, Lei Guan, Kai Wu
Biomass is an important part of renewable energies and characterized by physical properties and structures, including high moisture content, heterogeneous size, and low density. Wet filamentous biomass particle drying was performed in a rotary kiln, aiming to get the appropriate moisture content. To investigate the drying characteristics of biomass particles, a mathematical model on the heat and mass transfer was proposed. Experiments with filamentous biomass particles under selected conditions were compared to simulations and the feasibility of mathematical models was verified. Furthermore, the transfer of heat and mass between the wet filamentous biomass particle and gas flow was described in terms of rotary drum temperatures, gas flow velocities and gas temperatures. The aim was to gain more information on temperature, moisture content, and the moisture evaporation rate of wet filamentous biomass particles within a rotary kiln during drying processes. The simulation results indicated that the drum temperature could greatly affect the drying behaviors of particles. The temperature and moisture content of particles were marginally affected by properties of the gas flow. The results show that the proposed models offer effective methods to investigate the drying characteristics of wet filamentous biomass particles.
Production of 2-methylfuran from biomass through an integrated biorefinery approach Fuel Process. Technol. (IF 3.956) Pub Date : 2018-06-07 Inaki Gandarias, Sara García-Fernández, Iker Obregón, Iker Agirrezabal-Telleria, Pedro Luis Arias
Herein we present a high yield 2-methylfuran production process with the required features to be implemented in a future integrated biorefinery. The strategy is based on the right solvent selection, 2-methyltetrahydrofuran, which i) can be used to extract the reactant, furfural, from the aqueous solution obtained after corncob biomass hydrolysis; ii) allows for highly selective 2-methylfuran production form furfural with up to 80% yields and iii) presents suitable biofuel properties in the gasoline range. Using this innovative approach, two energy intensive separation steps are avoided: the initial furfural purification and the final solvent/product complete separation. Further benefits of this process arise from the developed low-cost, selective, and reusable Cu-Co/γ-Al2O3 catalyst.
The effect of disintegrated iron-ore pellet dust on deposit formation in a pilot-scale pulverized coal combustion furnace. Part II: Thermochemical equilibrium calculations and viscosity estimations Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-29 Hamid Sefidari, Bo Lindblom, Henrik Wiinikka, Lars-Olof Nordin, Andreas Lennartsson, Johanne Mouzon, Iftekhar Uddin Bhuiyan, Marcus Öhman
Fly ash particles from the combustion of solid-fuels together with disintegrated particles arising from iron-ore pellets result in accumulation of deposits on the refractory linings of the grate-kiln induration machine during the iron-ore pelletizing process. The deposits amass in the high-temperature regions of the induration furnace thus disturbing the flow of gas and pellets. Therefore, to tackle the above-mentioned issues, an understanding of deposit formation mechanism is of crucial importance. This study was conducted with the objective of addressing the effect of disintegrated iron-ore pellet dust on deposit formation and the mechanisms behind deposition (slagging) in the grate-kiln process. A comprehensive set of experiments was conducted in a 0.4 MW pilot-scale pulverized-coal- fired furnace where three different scenarios were considered as follows; Case 1 (reference case): Coal was combusted without the presence of pellet dust. Case 2: Natural gas was combusted together with simultaneous addition of pellet dust to the gas stream. Case 3: Coal was combusted together with the addition of pellet dust simulating the situation in the large-scale setup. Fly ash particles and short-term deposits were characterized and deposition was addressed in Part I of this study. In light of the experimental observations (Part I) and the thermochemical equilibrium calculations (Part II), a scheme of ash transformation during the iron-ore pelletizing process was proposed. The dissolution of hematite particles into the Ca-rich-aluminosilicate melt (from the coal-ash constituents) decreased the viscosity and resulted in the formation of stronger (heavily sintered) deposits. Overall, this pilot-scale work forms part of a wider study which aims at deepening the understanding of ash transformation phenomena during the large-scale pelletizing process.
Measurements of particulate matter concentration by the light scattering method: Optimization of the detection angle Fuel Process. Technol. (IF 3.956) Pub Date : 2018-07-03 Dong Chen, Xiaowei Liu, Jinke Han, Meng Jiang, Yishu Xu, Minghou Xu
The accuracy of the particulate matter emission measurement in coal-fired power plants has been enhanced to meet stricter environmental standards. This study discusses the effect of particle size on the in situ concentration measurement of particulate matter by the integrated light scattering method and optimization of the detection angle. The mass concentration sensitivities of five common particles with aerodynamic sizes ranging from 0.05–10 μm have been calculated based on Mie scattering theory at different scattering angles. The scattering light intensity of particles at forward scattering angles has larger magnitudes than that of the back-scattering angles, and the mass sensitivity is remarkably great at small angles. In addition, the fly ash and quartz particles are found to have nearly the same sensitivities at any particle size and scattering angle, and both have maximum values near 1 μm. Then, a real-time aerosol concentration measurement setup was built to study the effect of the particle size and the best detection angle. The results indicate that the optical measurement setup performs in real time and accurately shows good agreement with the calculations. Four quartz particles were represented in the fly ash after the dust collection in power plants was tested and the size factor was found to vibrate with the detection angles. Additionally, 25° is found to be the best detection angle to reduce the size effect. Finally, the optimal detection angle is comprehensively discussed based on the sensitivity, zero drift and size factor, also allowing for the particle density and refractive index. It is found that at angles of ~25°, the size factor and zero drift are lowest, while the sensitivity is relatively high; this outcome helps to reduce the measurement error of the real time-mass concentration of particulates.
Improved catalytic upgrading of simulated bio-oil via mild hydrogenation over bimetallic catalysts Fuel Process. Technol. (IF 3.956) Pub Date : 2018-07-03 Junhao Chen, Shurong Wang, Liang Lu, Xing Zhang, Yixi Liu
Biobased chemicals from the catalytic depolymerization of Kraft lignin using supported noble metal-based catalysts Fuel Process. Technol. (IF 3.956) Pub Date : 2018-07-04 I. Hita, P.J. Deuss, G. Bonura, F. Frusteri, H.J. Heeres
Butanol synthesis from ethanol over CuMgAl mixed oxides modified with palladium (II) and indium (III) Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-28 Olavo Micali Perrone, Francesco Lobefaro, Michele Aresta, Francesco Nocito, Mauricio Boscolo, Angela Dibenedetto
Ethanol conversion to butanol was investigated over mixed oxides derived from hydrotalcites modified with copper, palladium or indium. The reaction was carried out in the 403–573 K temperature range using stainless steel reactors. The presence of indium or palladium in the catalyst influences the temperature of reaction so that it was possible obtain butanol at temperature as low as 423 K. This is in line with the fact that the addition of metals with high hydrogen-transfer capacity makes faster all steps of the reaction with great energy saving. The best selectivity to butanol (65%) was achieved using In-CuMgAl catalysts with 3% of ethanol conversion at a temperature as low as 443 K.
Interesterification of rapeseed oil catalysed by a low surface area tin (II) oxide heterogeneous catalyst Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-17 Leonardo Interrante, Samir Bensaid, Camilla Galletti, Raffaele Pirone, Benedetto Schiavo, Onofrio Scialdone, Alessandro Galia
The interesterification of rapeseed oil was performed in a batch reactor using for the first time low surface area massive tin(II) oxide as heterogeneous catalyst and methyl acetate as acyl acceptor. The effect of reaction temperature, methyl acetate to oil molar ratio and catalyst loading on the performances of the process were investigated. Yields in fatty acid methyl esters (FAMEs) and triacetin (TA) up to 90% and 70% respectively, were achieved after 4 h of reaction time at 483 K in the presence of 0.69 mol of SnO per mole of rapeseed oil using a methyl acetate to oil molar ratio of 40. Quite interestingly, the catalyst performances improved when water was added to the reactions system. Moreover the same catalyst sample was used three consecutive times without observing any depletion of the catalytic activity. Collected results indicate that SnO is a promising heterogeneous catalyst for the interesterification of triglycerides with methyl acetate.
Prediction of crude oil blends compatibility and blend optimization for increasing heavy oil processing Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-12 Rajeev Kumar, Ravi Kumar Voolapalli, Sreedevi Upadhyayula
Pitch-derived N-doped porous carbon nanosheets with expanded interlayer distance as high-performance sodium-ion battery anodes Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-12 Mingyuan Hao, Nan Xiao, Yuwei Wang, Hongqiang Li, Ying Zhou, Chang Liu, Jieshan Qiu
The effect of disintegrated iron-ore pellet dust on deposit formation in a pilot-scale pulverized coal combustion furnace. Part I: Characterization of process gas particles and deposits Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-11 Hamid Sefidari, Bo Lindblom, Henrik Wiinikka, Lars-Olof Nordin, Johanne Mouzon, Iftekhar Uddin Bhuiyan, Marcus Öhman
To initiate the elucidation of deposit formation during the iron-ore pelletization process, a comprehensive set of experiments was conducted in a 0.4 MW pilot-scale pulverized-coal-fired furnace where three different scenarios were considered as follows; Case 1 (reference case): Coal was combusted without the presence of pellet dust. Case 2: Natural gas was combusted together with simultaneous addition of pellet dust to the gas stream. Case 3: Coal was combusted together with the addition of pellet dust simulating the situation in the large-scale grate-kiln setup. Particles and deposits were sampled from 3 positions of different temperature via a water-cooled sampling probe. Three distinct fragmentation modes were identified based on the aerodynamic particle diameter (Dp). The fine mode: Particles with 0.03 < Dp < 0.06 μm. The first fragmentation mode: Particles with 1 < Dp < 10 μm. The second fragmentation mode: Coarse particles (cyclone particles, Dp > 10 μm). A transition from a bimodal PSD (particle size distribution) to a trimodal PSD was observed when pellet dust was added (Case 3) and consequently the elemental bulk composition of the abovementioned modes was changed. The most extensive interaction between pellet dust and coal-ash particles was observed in the coarse mode where a significant number of coal ash globules were found attached to the surface of the hematite particles. The morphology of the sharp-edged hematite particles was changed to smooth-edged round particles which proved that hematite particles must have interacted with the surrounding aluminosilicate glassy phase originating from the coal ash. The short-term deposits collected during coal combustion (Case 1) were highly porous in contrast to the high degree of sintering observed in the experiments with pellet dust addition (Case 3) which is attributed to the dissolution of hematite particles in the aluminosilicate glassy phase. The results suggest that pellet dust itself (Case 2) has low slagging tendency, independent of temperature. However, when coal-ash is present (Case 3), auxiliary phases are added such that tenacious particles are formed and slagging occurs.
Effect of solvents on the microstructure aggregation of a heavy crude oil Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-12 Mario Minale, Maria C. Merola, Claudia Carotenuto
Co-pyrolysis of oily sludge and rice husk for improving pyrolysis oil quality Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-11 Bingcheng Lin, Qunxing Huang, Yong Chi
Co-pyrolysis of oily sludge and rice husk was conducted in a fixed-bed reactor to investigate the effects of interactions on the products and improve the quality of the pyrolysis oil. The synergy can be attributed to the catalytic effects of ash and alkali metals derived from biomass. SARA results showed that synergy enhanced the quality of oil product by promoting the content of saturates and aromatics and reducing heavy fractions. Gas chromatography/mass spectrometry results showed that the interaction increased the concentration of chain hydrocarbons and significantly reduced the content of oxygenated compounds by 46–93%. The gas yield was improved due to the promotion of secondary reactions and more H2, CO and C1–C2 hydrocarbons were generated. Additionally, though the emission of H2S was restrained, the distribution of sulfur in oil and gas phases was promoted.
The impact of dry torrefaction on the fast pyrolysis behavior of ash wood and commercial Dutch mixed wood in a pyroprobe Fuel Process. Technol. (IF 3.956) Pub Date : 2018-05-08 Georgios Archimidis Tsalidis, Christos Tsekos, Konstantinos Anastasakis, Wiebren de Jong
In this study torrefied feedstocks, consisting of mixed wood and wood residues torrefied at 300 °C and ash wood torrefied at 250 and 265 °C, were pyrolyzed in a pyroprobe at five pyrolysis temperatures (600–1000 °C) and a fast heating rate (600 °C·s−1) to investigate the effect of torrefaction on the formation of volatiles and their evolution in a 100 kW circulating fluidized bed gasifier. Results showed that torrefaction converted mostly the hemicellulose content of feedstocks. Furthermore, torrefaction resulted in decreasing the bio-oil and gas yields, increasing the char and phenol yields and not affecting the polyaromatic hydrocarbons yield. Phenol and naphthalene showed the largest yield at 600–700 °C and 800–1000 °C, respectively. At such high temperatures, the rest polyaromatic hydrocarbons showed yields similar to phenol's. At 900 °C torrefaction affected mainly the phenolic species, with 4-propyl-phenol being the dominant species of its group for mixed wood and wood residues feedstock. In the gasifier, H2 and CO2 yields increased, CH4 yield remained constant, and CO yield depended on tar conversion and oxidation and steam reactions. The phenol and naphthalene yields further decreased and increased, respectively, whereas, polyaromatic hydrocarbons did not change in the gasifier.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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