Experimental adsorption water desalination system utilizing activated clay for low grade heat source applications
Introduction
Energy, fresh-water, and environment are inter-related features that infuse all our activities in the earth [1], [2], [3]. Utilizing renewable energy in desalination system has high interest from researchers. Adsorption desalination-cooling systems (ADCS) have been becoming a promising alternative to traditional cooling and desalination systems avoiding their common problems such as high energy consumption and global warming [4]. Unlike the traditional units, a sorption system utilizes low-grade heat from renewable sources or industrial wastes to produce freshwater and cooling effect [5], [6], [7]. These systems depend on the adsorbent materials characteristics represented in adsorption isotherms (Adiso) and adsorption kinetics (Adkin).
Disadvantage of the ADCS is its quite low performance [8]. Accordingly, the main concern of researchers in this field is to enhance the performance in several ways, one of which is to find new materials. Ferroaluminophosphate/water was presented as an adsorption pair for ADCS by Kim et al. [4]. Characteristics of adsorption were experimentally tested. The results reported that the equilibrium water uptake was five times higher than silica gel at 30 °C adsorption and 70 °C desorption. Kusgens et al. Metal-organic frameworks (MOF) was presented as new adsorption materials [9,10]. Table 1 illustrates a summary of a number of studies concerned about adsorption characteristics of different adsorption material with water vapor adsorbate.
Performance of ADCS had been investigated in many studies. Youssef et al. [11] investigated experimentally the performance of ADCS employing CPO-27(Ni). The results exhibited that in case of Tcond (from 5 to 30 °C) and Teva (10 °C), specific daily water production (SDWP) and specific cooling power (SCP) were 3.2–7.5 m3/ton and 100–200 W/kg, respectively. Kim et al. [17] presented a new scheme for time-schedule of ADCS. The result illustrated that ADCS performance depended on the value of initial time lag. Elsayed et al. [22] present a mathematical analysis of the performance of ADCS employing (CPO-27(Ni), MIL-101(Cr) and aluminum-fumarate adsorption materials. The SDWP was 4.3 m3/ton for (CPO-27(Ni), 6 m3/ton for aluminum-fumarate and 11 m3/ton for MIL-101(Cr).
Montmorillonite is a natural clay mineral which is mostly composed of aluminosilicate. Egyptian clay found in the northern part of the Western Desert has the highest percentage of montmorillonite (60–90%) with the lowest impurities [23]. Abdel-Motelib et al. [24] analyzed a commercial clay product (smecta) produced by Amriya for Pharmaceutical Industries, Alexandria, Egypt. The XRD of smecta indicates that pure montmorillonite is the main constituent. Therefore, smecta is considered as a sample of montmorillonite in the present experiments. Acid activation of clays with HCl is described in many studies [25], [26], [27], [28]. It was concluded that the optimum concentration of HCl activation is 2 mole HCl for the highest surface area. Higher surface area is lead to higher adsorption capacity as reported in Ref. [29].
The present study investigates experimentally adsorption characteristics of water vapor onto acid activated montmorillonite for ADCS. A theoretical model has been developed to the investigated ADCS performance with utilizing AAM. An experimental adsorption desalination-cooling (ADC) test rig has been constructed to study the ADCS performance with montmorillonite/water vapor pair and axial finned tube adsorption bed design.
Section snippets
Material
Infra-red spectra, IR, is an adequate characterization technique for acid activated clays because it is very sensitive to clay structure modifications [30]. IR spectrum are obtained using Fourier transform-IR-spectroscopy (Alpha Bruker, Germany) at Sohag University with 400–4000 cm−1 spectral range via Attenuated total reflection, ATR.
Montmorillonite is activated by hydrochloric acid, HCl for different concentrations (0.5 to 2 mole of HCl) for 12 h. IR spectrum, IR, for montmorillonite and
Adsorption isotherms
In this section test procedure and adsorption models are presented. The AAM is dried and regenerated at 120 °C for 8 h under vacuum pressure of 50 Pa. Water vapor is charged to the dosing chamber from evaporator at a certain pressure. After stable initial temperature and pressure readings the valve (V2) is opened to start adsorption process. The dosing chamber pressure is reduced steadily. During adsorption process, temperature of adsorber increases and decreases again to its initial value.
Adsorption kinetics
In this section test procedure and the Linear Driving Force model, LDF, for montmorillonite (with average grain size 1 × 10−3 mm) are presented. The steps of Adkin is the same steps of Adisosection (3) but each run steps take 30 s to explore the time influence on the adsorption rate. The vapor relative pressure is taken from 0.65 to 0.7 at each step.
The behavior uptake of semi-infinite medium can be expressed as [38]:where is given by [39];The values and (Dso)
Results for adsorption characteristics (Adiso and adkin)
Fig. 3 illustrates Adisoof montmorillonite/water vapor pair for different concentrations at 25 °C. Also, the figure specifies that the activated montmorillonite with 2 mole HCl has a maximum adsorption capacity (Co) of about 0.52 kgwater vapor/kgAAM at 25 °C while, the raw montmorillonite has only 0.30 kgwater vapor/kg. The acid activation rise the adsorption capacity for montmorillonite by about 73%. This is because the acid attacked the layers to replace the exchangeable montmorillonite
Mathematical model
Fig. 7a and 7b shows modes of single-bed ADCS filled with AAM (2 mole HCl) as an adsorption material. Operation procedure, ADCS basics and model assumptions can be found in the literature [43], [44], [45].
The mass balance of ADCS is given by;
The components energy balances are given by Eqs. (14–16) [46,47];
Experiments of adsorption desalination system
This section expresses the experimental test rig of ADCS. The test rig is based on a single-bed cycle, which has the simplest adsorption system structure. Fig. 8 shows the preset experimental test rig for ADCS. The test rig comprises three main components; adsorption bed, evaporator and condenser. The adsorption bed consists of a steel shell (600 mm length and 150 mm diameter) which contains three axial finned tubes heat exchangers (Hex) packed with adsorbent material. The adsorption bed
Temperature profiles
The performance of ADCS can be assessed by observing the inlet and outlet heat transfer fluids temperatures variance. Fig. 11 displays a comparison between the simulated and experimental heat transfer fluids temperatures variance for the each system components as well as the adsorption beds temperatures at the previous mentioned operating conditions. The comparison is performed on the ADCS operating over three cycles.
As it can be observed, the simulated model calculates well the different
Conclusions
Adsorption characteristics (Adisoand Adkin) of AAM/water vapor pair have been expressed. The maximum adsorption capacity is about 0.52 kg/kg of AAM. A new proposed single-bed ADCS driven by low grade heat source is designed, built, and tested as an innovative axial finned tube packed with 2.65 kg acid activated montmorillonite as adsorbent material. The experimental results exhibited that, at 85 °C Thwi that can be achieved from low grade heat source such as solar energy or waste heat, the
CRediT authorship contribution statement
Ehab S. Ali: Experimental work, Software, Formal analysis, Data curation, Writing - original draft, Visualization. Ahmed A. Askalany: Conceptualization, Methodology, Data curation, Formal analysis, Writing - review & editing, Supervision. K. Harby: Supervision, Writing - original draft, Writing - review & editing. Mohamed Refaat Diab: Formal analysis, Data curation, Writing - original draft, Writing - review & editing. Bahgat.R.M. Hussein: Formal analysis, Data curation. Ahmed S. Alsaman:
Declaration of Competing Interest
The authors whose names are listed immediately below certify that they have NO affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in
References (56)
- et al.
A new approach integration of ejector within adsorption desalination cycle reaching COP higher than one
Sustain. Energy Technol. Assessm.
(2020) - et al.
Hybrid solar desalination systems driven by parabolic trough and parabolic dish CSP technologies: technology categorization, thermodynamic performance and economical assessment
Energy Convers. Manag.
(2020) - et al.
A novel combined reverse osmosis and hybrid absorption desalination-cooling system to increase overall water recovery and energy efficiency
J. Clean. Prod.
(2021) - et al.
Adsorption characteristics of water vapor on ferroaluminophosphate for desalination cycle
Desalination
(2014) - et al.
A daily freshwater production of 50 m3/ton of silica gel using an adsorption-ejector combination powered by low-grade heat
J. Clean. Prod.
(2021) - et al.
Recycling brine water of reverse osmosis desalination system employing adsorption desalination system: a theoretical study
Desalination
(2017) - et al.
Solar-powered ejector-based adsorption desalination system integrated with a humidification-dehumidification system
Energy Convers. Manag.
(2021) - et al.
A novel cycle for adsorption desalination system with two stages-ejector for higher water production and efficiency
Desalination
(2020) - et al.
Experimental optimization of the cycle time and switching time of a metal organic framework adsorption desalination cycle
Energy Convers. Manag.
(2021) - et al.
Metal-organic frameworks in cooling and water desalination: synthesis and application
Renew. Sustain. Energy Rev.
(2021)
Experimental investigation of adsorption water desalination/cooling system using CPO-27Ni MOF
Desalination
Performance evaluation of a solar-driven adsorption desalination-cooling system
Energy
Measurements of water vapour sorption isotherms for RD silica gel, AQSOA-Z01, AQSOA-Z02, AQSOA-Z05 and CECA zeolite 3A
Microporous Mesoporous Mater.
Experimental investigation of silica gel-water adsorption isotherm characteristics
Appl. Therm. Eng.
Thermodynamic frameworks of adsorption kinetics modeling: dynamic water uptakes on silica gel for adsorption cooling applications
Energy
Optimal working pairs for solar adsorption cooling applications
Energy
Adsorption cold storage system with zeoliteewater working pair used for locomotive air conditioning
Energy Convers. Manag.
Performance analysis of four bed adsorption water desalination/refrigeration system, comparison of AQSOA-Z02 to silica-gel
Desalination
Suitability of a miocene bentonite from North Western desert of Egypt for pharmaceutical use
Appl. Clay Sci.
Thermo-physical properties of silica gel for adsorption desalination cycle
Appl. Therm. Eng.
Chemical and thermal properties of organoclays derived fromhighly stable bentonite in sulfuric acid
Appl. Clay Sci.
Investigation of the initial stages of the montmorillonite acid-activation process using DFT calculations
Appl. Clay Sci.
Adsorption desalination-cooling system employing copper sulfate driven by low grade heat sources
Appl. Therm. Eng.
Weather effect on a solar powered hybrid adsorption desalination-cooling system: a Case Study of Egypt's Climate
Appl. Therm. Eng.
Solar-powered ejector-based adsorption desalination system integrated with a humidification-dehumidification system
Energy Convers. Manag.
Adsorption desalination: an emerging low-cost thermal desalination method
Desalination
Thermoeconomic assessment of an adsorption cooling/desalination cycle coupled with a water-heated humidification-dehumidification desalination unit
Energy Convers. Manag.
A review on development of adsorption cooling-Novel beds and advanced cycles: review Article
Energy Convers. Manag.
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