Cryogenic Separation Research Articles

Membrane-Based Technologies for Post-Combustion CO2 Capture from Flue Gases: Recent Progress in Commonly Employed Membrane Materials.

Carbon dioxide (CO2), which results from fossil fuel combustion and industrial processes, accounts for a substantial part of the total anthropogenic greenhouse gases (GHGs). As a result, several carbon capture, utilization and storage (CCUS) technologies have been developed during the last decade. Chemical absorption, adsorption, cryogenic separation and membrane separation are the most widely used post-combustion CO2 capture technologies. This study reviews post-combustion CO2 capture technologies and the latest progress in membrane processes for CO2 separation. More specifically, the objective of the present work is to present the state of the art of membrane-based technologies for CO2 capture from flue gases and focuses mainly on recent advancements in commonly employed membrane materials. These materials are utilized for the fabrication and application of novel composite membranes or mixed-matrix membranes (MMMs), which present improved intrinsic and surface characteristics and, thus, can achieve high selectivity and permeability. Recent progress is described regarding the utilization of metal-organic frameworks (MOFs), carbon molecular sieves (CMSs), nanocomposite membranes, ionic liquid (IL)-based membranes and facilitated transport membranes (FTMs), which comprise MMMs. The most significant challenges and future prospects of implementing membrane technologies for CO2 capture are also presented.

Integration of large-scale pressure swing adsorption units in local hospitals in Morocco: Design, simulation and performance evaluation

To enhance the availability and accessibility of medical oxygen in local hospitals in Morocco, a solid approach has been conducted for upscaling PSA unit. This comprehensive research involves the design, simulation, and performance evaluation of the PSA unit to confirm the functioning and efficiency of the system. The design phase meticulously considers hospital oxygen requirements, utilizing data from multiple local hospitals. Objectives include using PSA technology to produce high-purity oxygen, providing autonomy for 30–35 patients at 5 L/min. Although, the hospital needs 650 L/min of medical oxygen in order to supply all the patients. The study reveals promising results for oxygen concentration which reaches a maximum of 96 % of oxygen under 29 mol/min of flowrate which give an equivalent to 660 L/min volumetric flow rate that can supply the needs of local hospitals within a short time. These findings will enable hospitals decision makers to consider large PSA over cryogenic separation unit that has been known with major drawbacks in delivery and pose logistical and environmental problems and to ensure a steady and reliable supply of medical oxygen, ultimately contributing to improved healthcare services and patient care.

Stable isotope analysis of atmospheric CO2 using a Gasbench II-Cold Trap-IRMS setting.

The measurement of the stable carbon and oxygen isotope ratio of (atmospheric) carbon dioxide (CO2 ) is a useful technique for the investigation and identification of the sources and sinks of the most abundant greenhouse gases by far. For this reason, we are presenting a measuring system here that enables a wide range of users to carry out stable isotope analysis of atmospheric CO2 using off-the-bench hardware and software. The fully automated system uses cryogenic and gas chromatographic separation to analyse CO2 from 12-mL whole air samples and consists of an autosampler, a Gasbench II (GB), a downstream cryo trap and a continuous flow gas interface feeding into a sector field mass spectrometer (GC Pal/GB/Cold Trap/ConFlo IV/DeltaV Plus). The evaluation of the system performance was based on the analysis of samples prepared from eight CO2 sources (four CO2 reference gases and four artificial air tanks). The overall measurement uncertainty (averaged single standard deviation (1σ) of measurement replicates from each CO2 source) in the determination of the carbon and oxygen isotope ratio was 0.04‰ and 0.09‰ (n = 24). Furthermore, we were able to show that the measurement data also allowed for the quantification of the CO2 mole fraction, with a precision of 1.2μmol mol-1 in the analysis range of 400-500 μmol mol-1 . Our protocol provides a detailed description of the measurement set-up and the analysis procedure, how raw data should be evaluated and gives recommendations for sample preparation and sampling to enable a fully automated whole air sample analysis. The quantification limit of CO2 mole fractions and measurement precision for carbon and oxygen isotope ratios of CO2 should meet the requirements of a wide range of users.

Design, Fabrication, and Test of a Prototype of Matrix Heat Exchanger for Cryogenic Distillation of Hydrogen Isotopes

The following properties are needed to increase the efficiency of refrigeration, liquefaction, and cryogenic separation cycles: Heat exchangers must have high effectiveness doubled by high compactness; small temperature differences between incoming and outgoing flows must be ensured to increase efficiency; there must be a large heat transfer surface, relative to the volume of the heat exchanger, to minimize heat loss; there must be a high heat transfer rate to reduce the transfer area; there must be a small pressure drop to reduce compression costs; and there must be high reliability with minimal maintenance. All these properties are entirely fulfilled by the designed matrix heat exchangers (MHEs). This paper presents the results of the research program developed by the team of the Cryogenic Laboratory from INC-DTCI ICSI Ramnicu Valcea, which included procedural stages of the realization and preliminary results of the characterization of the MHE-type heat exchanger in a narrow range of values to achieve a proper solution for a heat exchanger to be used for cryogenic purposes, such as cooling the gas mixture at the entrance of a distillation column of hydrogen isotopes and running at low pressure (typically regimes of 0.5 to 2.0 bars) and flows. Within several experimental campaigns, different assembly and testing techniques of the matrix heat exchanger (MHE) prototype were performed to achieve numerical data for the temperature and pressure drops along the heat exchanger and to verify ANSYS Fluent numerical simulation results. The results showed that for the designed and tested MHE prototype, a temperature drop of up to almost 230 K can be obtained at the established parameters correlated with pressure losses within a few millibars (the maximum recorded pressure drop is 80 mbars), small dimensions (64 mm high), and accessible weight (up to 2000 g).

Multiobjective optimization of membrane in hybrid cryogenic CO2 separation process for coal-fired power plants.

Post-combustion carbon dioxide (CO2) capture is considered a potential method to mitigate CO2 emissions from fossil fuels burned in power plants. In recent years, combining two different methods of post-combustion CO2 capture such as membrane and cryogenic distillation has been explored for availing the advantages of each method. This study focuses on the optimization of membranes for developing the membrane-cryogenic distillation process. For this purpose, a process flow sheet is developed, and simulation with model components such as compressor, heat exchanger, turbo expander, and distillation column is carried out using Aspen Plus. A membrane model is developed using in-house MATLAB code, and optimization is done to achieve higher concentration and recovery of CO2 using the MOJAYA algorithm. The membrane model is coupled to Aspen Plus through component object model (COM) technology. In this investigation, a hollow fiber membrane is considered. The optimized specifications of membrane modules are length, number of hollow fibers, feed pressure, and permeate pressure which are 0.3 m, 100,000, 5.76 bar, and 0.1 bar, respectively. This analysis results in the purity and recovery of the process of 99.8 and 90%, respectively, and an energy penalty of around 1.74 MJ/kg of CO2. A comparison of other processes available in the literature reveals that the current study renders maximum purity and recovery with a minimum energy penalty.

Optimal design and analysis of a liquid hydrogen and LNG coproduction system with multistage multicycle cascade refrigeration system

The efficient utilization of industrial by-products, such as synthetic ammonia exhaust tail gas and coke oven gas, has been neglected in China for a long time. Thus, the development of novel high-efficiency industrial by-product utilization methods is of great importance. A multistage multicycle cascade refrigeration system utilized for hydrogen liquefaction with LNG production is constructed in this paper. The industrial by-products after purification directly enter into cryogenic separation liquefaction system. Liquid hydrogen and LNG are produced after pre-cooling, separation and liquefaction respectively. Process configuration, thermodynamic analysis, optimization model with GA is conducted. The specific power consumption of the multistage multicycle cascade system is within 14.0–17.4 kWh/kmol (feed gas). The proposed process can be used in the efficient utilization of industrial by-products with high exergy efficiency (33.6%∼41.45%) and great economic benefits.

Thermodynamic analysis of cold energy recovery from LNG regasification

The LNG market connects numerous export and import markets, and the global LNG trade has been growing steadily. Despite the availability of multiple alternatives, only a small fraction of this global cryogenic potential is currently utilized, and a negligible number of regasification terminals are equipped with cold energy recovery systems. This paper explores various options for recovering cold energy from LNG regasification processes including electricity production, refrigeration, cryogenic separation processes, CO 2 capture and liquefaction. The present study examines the industrial recovery options, proposing both conventional and innovative process schemes and analysing them in terms of their thermodynamic modelling and feasibility. Nine case studies were selected and simulated using Aspen Hysys software, considering material and energy balances. Specific energy consumptions are calculated, and an exergetic comparison methodology is adopted to provide a unified approach capable to embrace heterogeneous systems utilizing mechanical/electrical energy, thermal energy, and “chemical energy”. The temperature profiles are examined, and sensitivity analyses are performed on key parameters. The integration of direct cooling and condensation brings high exergy efficiency of above 40% and economic advantages due to the absence of an external refrigeration cycle. Coupling regasification with CO2 liquefaction reduces specific energy consumption by 53% compared to the conventional process. Similarly, in the case of an ethylene production plant, energy consumption is reduced by 95%. Simulations for electricity generation using an ORC cycle with LNG as the cold source achieve around 25% exergy efficiency, but the LCOE (Levelized Cost of Electricity) is attractive, ranging from 0.07 to 0.09 €/kWh. Integration with an Air Separation Unit (ASU) for cryogenic distillation leads to a 41% decrease in specific energy consumption. Further integration with Allam and cascade ORC cycles has been simulated. Globally, air separation shows exergy efficiencies of 37–38%, which is higher than the average 25% obtained from conventional thermodynamic cycles with low-temperature hot sources. Regarding cryogenic CO2 capture, it exhibits lower specific energy consumption compared to traditional processes. The exergy efficiency is high at 22%, and the LCOP (Levelized Cost of CO2 Production) of 55 €/ton is attractive for carbon capture processes that can be coupled with regasification units and NG utilization (a.e. for hydrogen and electricity production).

High D2/H2 selectivity performance in MOF-303 under ambient pressure for potential industrial applications

The commercial demand for D2 is poised to increase significantly; however, the low natural abundance and the energy- and capital-intensive industrial separation (i.e., 24 K cryogenic distillation) will hamper future scientific and industrial growth in isotopologue separation. Alternatively, kinetic quantum sieving (KQS)-based adsorptive D2 separation has been proposed recently, but the separation performance is reported mostly at near zero pressure or in the sub-few ten mbar range. Herein, an Al-based Metal-Organic Framework, MOF-303, with 1-D narrow-micro pores is studied for D2/H2 adsorptive separation at ambient pressure. Cryogenic thermal desorption spectroscopic analysis of MOF-303 confirmed that the synergetic effect of binding affinity & enhanced KQS (owing to molecular rearrangement of D2 adsorbed phase at high pressure induced by strong D2 confinement), along with D2 partial condensation, leads to a significant increase in the D2 uptake with increasing exposure pressure up to 1,000 mbar. Consequently, a remarkable selectivity of 21.6 at 25 K has been achieved even at an operating pressure of 1000 mbar, which is an industry-friendly condition. The observed D2/H2 separation selectivity is about ten times higher than that of the industrial cryogenic method (best selectivity of below 2.5 at 24 K), and comparable to the performance of the adsorbent materials already reported with low operating pressure, making adsorptive D2/H2 separation through MOF-303 an alternative for cryogenic industrial isotopologue separation.

Thermodynamic and economic analysis of a new methanol steam reforming system integrated with CO2 heat pump and cryogenic separation system

A novel design has been developed to optimize the performance of the methanol steam reforming (MSR) system by integration with a CO2 heat pump (HP) and a cryogenic separation system. In the integrated system, the cryogenic separation system separates most of the CO2 from the MSR byproducts in liquid phase and the rest chemical energy of CO is recycled to MSR after combustion. Besides, the CO2 HP system organically connects the MSR process and the cryogenic separation system, which is capable to absorb the waste energy from MSR and also provides cryogenic energy to cryogenic separation system and mid-temperature heat to MSR preheating process. By such incorporation, the waste heat and the energy of CO can be fully utilized and the CO2 from MSR can be exported in liquid phase as a secondary product. Based on a 20,000 ton/year MSR plant, the energy and exergy analyses reveal that the energy and exergy efficiency are promoted by 5.57% and 5.15%, respectively. Besides, the profit of the integrated design is 139.6 M$ higher than that of the conventional system over the lifespan. Furthermore, sensitivity evaluation shows that the optimal reaction temperature is approximately 250 °C and the higher reaction pressure is favorable.

Novel aminated F-Ce nanosheet mixed matrix membranes with controllable channels for CO2 capture

Membrane separation is a novel technology that has been widely studied for efficient CO2 capture. This study aims to synthesize novel porous amino-functionalized nanosheets using PEI (polyethyleneimine) (PEI-F-Ce) and PEI-F-Ce/polyethylene oxide (PEO) mixed matrix membranes (MMMs). PEI-F-Ce nanosheets were prepared via the electrostatic self-assembly method, allowing for the adjustment of both lateral and pore sizes of the nanosheets by varying the PEI concentration. The MMMs loaded with 2 % PEI-F-Ce-2.5 nanosheets exhibit excellent CO2 permeability (641 Barrer) and outstanding CO2/N2 selectivity (70.1). These values surpassed those of pure PEO membranes by 62 % and 53 %, respectively, exceeding the 2019 upper bound. PEI-F-Ce-2.5 nanosheets with a stable pore channel 3.406 nm improved CO2 transport and showed a large CO2 adsorption capacity of 1.32 mmol g−1, leading to enhanced the CO2/N2 reaction selectivity. Moreover, the reversible reaction of CO2 with –NH2 enhanced the CO2/N2 selectivity by 5.1 times at −20 °C, thereby highlighting its potential for cryogenic gas separation applications.

Highly-Controlled Soft-Templating Synthesis of Hollow ZIF-8 Nanospheres for Selective CO2 Separation and Storage.

Global warming is an ever-rising environmental concern, and carbon dioxide (CO2) is among its major causes. Different technologies, including adsorption, cryogenic separation, and sequestration, have been developed for CO2 separation and storage/utilization. Among these, carbon capture using nano-adsorbents has the advantages of excellent CO2 separation and storage performance as well as superior heat- and mass-transfer characteristics due to their large surface area and pore volume. In this work, an environmentally friendly, facile, bottom-up synthesis of ZIF-8 hollow nanospheres (with reduced chemical consumption) was developed for selective CO2 separation and storage. During this soft-templating synthesis, a combined effect of ultra-sonication and low-temperature hydrothermal synthesis showed better control over an oil-in-water microemulsion formation and the subsequent growth of large-surface-area hollow ZIF-8 nanospheres having excellent particle size distribution. Systematic studies on the synthesis parameters were also performed to achieve fine-tuning of the ZIF-8 crystallinity, hollow structures, and sphere size. The optimized hollow ZIF-8 nanosphere sample having uniform size distribution exhibited remarkable CO2 adsorption capability (∼2.24 mmol g-1 at 0 °C and 1.75 bar), a CO2/N2 separation selectivity of 12.15, a good CO2 storage capacity (1.5-1.75 wt %), and an excellent cyclic adsorption/desorption performance (up to four CO2 adsorption/desorption cycles) at 25 °C. In addition, the samples showed exceptional structural stability with only ∼15% of overall weight loss up to 600 °C under a nitrogen environment. Therefore, the hollow ZIF-8 nanospheres as well as their highly controlled soft-templating synthesis method reported in this work are useful in the course of the development of nanomaterials with optimized properties for future CO2 capture technologies.

Absorption-compression hybrid refrigeration analysis and application for energy conservation of cryogenic separation in propane dehydrogenation

Cryogenic separation is an energy extensive process in chemical industries and compression refrigeration (CR) is the most common refrigeration technology with huge energy consumption and carbon emission. Based on the principle and thermodynamic analysis of absorption refrigeration (AR) and CR, this paper puts forward serial AR-CR combined absorption-compression hybrid refrigeration (ACHR) technology as a substitution for traditional CR to conserve both power consumption and carbon emission. Industrial propane dehydrogenation is employed and the ACHR is introduced to accomplish the cryogenic separation by refrigerating temperature and load division. The phase transition of refrigerated streams encompassed by AR is crucial to the performance of ACHR. When the inter-connected temperature is determined to be 6 °C, the optimal refrigeration scenario is obtained. Through partial substitution of AR driven by waste heat for CR, the results show that the hybrid refrigeration can save 48.73% of power consumption and 110.8 GW h of energy per year, which is equivalent to the annual reduction of 39.8 kt standard coal and 0.12 Mt carbon emission. This work demonstrated that absorption-compression hybrid refrigeration is prospective in energy consumption and emission reduction industrially.

A comprehensive review on current trends and development of biomethane production from food waste: Circular economy and techno economic analysis

Biogas production from food waste with anaerobic digestion process and co-digestion process obtained high purity of biogas. Food waste consists of proteins, carbohydrates, inorganic compounds, fibre, sugars, and lipids. Fossil fuels have caused some environmental and human health problems, such as effects of global warming, greenhouse gas emissions. Biogas production is a simple process and is purified into methane and used in many applications, heat, electricity and vehicle fuel. Different types of food waste are collected and processed into biogas, which is essential for human use and as an alternative to fossil fuels. The collection of food waste, pre-treatment process, production of biogas, purification of biogas, upgradation of biomethane, and circular bioeconomy are clearly explained. Anaerobic digestion and co-digestion processes have increased biomethane yield, up gradation and purification of biogas have also been discussed. Five different types of upgradation processes are included, such as physical scrubbing, chemical scrubbing, pressure swing adsorption, membrane separation, and cryogenic separation. The upgradation process and the purity level also mentioned in this review, it represents the biomethane quality. Techno economic effects and circular bioeconomy levels are addressed in this review. Life cycle assessment, life cycle impact analysis and environmental impact level are discussed. However, Challenges and future perspectives of biogas production and to improve the biomethane purity level. 89% of the biogas production is obtained from fruit waste with anaerobic digestion, after the upgradation process, 99% purity of biomethane is separated.

4E analysis of the cryogenic CO2 separation process integrated with waste heat recovery

Carbon dioxide capture, utilization, and storage (CCUS) is an attractive method to reduce carbon dioxide (CO2) emissions originating from fossil fuels burned from large single-point sources. CO2 separation from a CO2-laden gas stream is the first stage of CCUS. In this investigation, a cryogenic distillation-based CO2 separation process (CCSP) is developed. CCSP is modified to utilize waste heat obtained in the process for reducing the energy consumption of CO2 separation. Two modifications are carried out in the process which include (i) heat integration (HI) with CCSP (CCSP + HI) of the reboiler with the heat from hot streams available in the process and further, (ii) energy recovery by using the organic Rankine cycle (ORC) operating between gas compressor temperature and ambient temperature (CCSP + HI + ORC). The parametric and 4 E (energy, exergy, economic, and environmental) analysis results obtained for the CCSP + HI, CCSP + ORC, and CCSP + HI + ORC processes are compared with those of CCSP. The net electrical energy required to operate the compressor for CCSP is 2.7%, 7%, and 21.8% higher than that for CCSP + HI, CCSP + ORC, and CCSP + HI + ORC, respectively.

Efficient recovery of C2+ alkanes from natural gas using porous ZIF-8/iso-hexadecane slurry on laboratory and pilot-scale

The efficient recovery of C2+ alkanes from natural gas is of great significance since the C2+ alkanes are the essential petrochemical raw material. This paper presents the novel absorption-adsorption hybrid method to recover the C2+ alkanes components from natural gas using a flowable zeolitic imidazolate framework-8 (ZIF-8)/iso-hexadecane slurry. The ZIF-8 particles have an excellent dispersion in the iso-hexadecane solvent. The sorption capacity for C2H6 and C3H8 in the slurry is significantly higher than that for CH4. Moreover, in competitive adsorption, the slurry showed a significant advantage for C2H6 and C3H8 over CH4. In the experiments of recovering C2+ alkanes from natural gas, the recovery ratio can reach a staggering 91.59%. Besides, in the regeneration tests, 97.79% of the sorption capacity for C2H6 can be recovered by vacuuming without temperature swings, and the characteristic structure of the recycled ZIF-8 remains intact. More encouragingly, a continuous pilot separation plant was established, and the test results show that the recovery ratio for C2+ alkanes can reach 86.75%. The excellent selective recovery performance is comparable to the mature cryogenic separation process. To our knowledge, this is the first time to apply metal–organic frameworks (MOFs) to separate natural gas on pilot-scale. This work has thus furthered the industrial application of MOFs in gas separation.

Recent advances in biogas production using various bio-waste’s and its potential application: An overview

With continuous increase in the global population, the energy consumption has increased tremendously which has primarily increased our dependence on fossil fuels, in tum causing great environmental problems. Depleting fossil fuels reserves and increased emission of toxic gases in our atmosphere is a big environmental hazard. Also in India, each year billions of dollars are spent for the import of these conventional fuels which further devaluates the currency there by causing a big setback to national economy.Biogas is an environment friendly fuel which has the capabilities to be used as fuel in future vehicles thereby, reducing the import of conventional fuels. The current biogas generation technologies available gives less yield in more days, with high percentage of impurities. The presence of incombustible gases such as CO2, H2S and water vapour reduces its calorific value and makes it difficult to transport and compress. Biogas with more than 90% methane can be obtained using processes like adsorption, absorption, cryogenic and membrane separation. Carbon emission between base CNG and purified biogas is the same.This review provides summary of biowaste materials like cattle dung, spoiled food, chicken manure, vegetable waste and rice husk. It has been seen that a substrate of Cow-Dung mixed with other biowastes like rice husk or vegetable peelings can satisfactorily achieve a yield hike of 44% under mesophilic(30–40 °C) condition with the pH of 4–7. Presence of certain catalyst like NaOH also positively affects the biogas generation. Biogas digesters fed with a substrate profile of 25% cow-dung and 75% food-waste give 80% higher yield within 10 days of loading with minimal impurities. Results of using this biogas mixed with CNG in engines is also elaborated.

Design and analysis of cryogenic CO2 separation from a CO2‐rich mixture

AbstractIn this study, we designed and optimized the main process for CO2 cryogenic separation and purification as well as the auxiliary process of refrigeration with ammonia, both these processes are modeled using Aspen HYSYS V11. The energy‐saving potential and greenhouse gas emission reduction potential of the process flow were analyzed using the Aspen Energy Analyzer V11. The effects of the plant inlet pressure, cooling temperature, tower pressure, and number of stages on two key parameters (energy consumption per unit of product and CO2 recovery rate) were studied in detail. Simultaneously, the appropriate design parameters of the plant were obtained, and the reason for the variation law was analyzed. Finally, grey relational analysis was used to explore the correlation between the influence factors and key parameters, indicating that the number of stages has the largest impact on the CO2 recovery rate and the energy consumption per unit of product, whereas tower pressure and cooling temperature have the least impact on the CO2 recovery rate and energy consumption per unit of product, respectively.

Purification of biogas for methane enrichment using biomass-based adsorbents: A review

Among the others, CO2 and H2S are the major impurities present in biogas which typically hampers its direct application as biofuel. Therefore, an upgradation for the purity of biogas is a high research endeavour. In the recent past, several attempts are made to improve the quality of biogas with a focus to reduce the impact of global warming due to the excessive release of CO2. This is interesting to indicate that most of the biogas cleaning methods are expensive and very rare documents detailed the usage of sustainable materials for the purification of biogas. Given that, developments in the applications of natural materials as low-cost adsorbents used for the purification of biogas are well documented in the present review paper. Globally more than 40% of the countries utilise water scrubbing as the most popular method for the separation of biomethane. This article also reviews the other most accepted technologies such as different types of scrubbing, swing adsorption, and cryogenic separation with biological upgradation. Hybrid biological methods are used in methane upgrading systems to increase production of pure CH4 while reducing the need for energy and chemicals. Moreover, the article also summarized different numerical models, frequently adopted for the prediction of the upgradation of biomass. Finally, the article concludes with major bottlenecks involved in the processes and recommended scientific directives towards successfully transforming bench-scale studies into large-scale implementation. So, this article will ensure the readers gather overall technical information on the upgradation of biogas obtained from the anaerobic digestion of biomass.

Design of Plate-Fin Heat Exchanger for CO2 Separation by Cryogenic Distillation

Carbon capture, utilization, and storage (CCUS) is a technique to curb carbon dioxide (CO2) emissions from significant point sources. CO2 separation is the first stage in the CCUS. Cryogenic CO2 separation is the emerging method of separating CO2 from different sources. Plate-fin heat exchanger (PFHE) is one of the compact heat exchangers generally used in cryogenic applications. Due to its advantages, it is also used in the cryogenic CO2 separation process. In this analysis, a PFHE is designed and analyzed by using an analytical method and Aspen software, and the results are compared. In the analytical design, the Maiti and Sarangi correlations are considered. The effect of the change in the thermos-physical properties on the volume and cost of the heat exchanger (HX) is analyzed. The energy penalty to separate CO2 from a CO2/N2 gas mixture with a 30% CO2 concentration is observed to be 1.063 MJ/kg of CO2. The volumes of HXs “A” and “B” determined by the analytical approach are found to be around 0.323 m3 and 0.978 m3, respectively. The volumes of HXs “A” and “B” by the Aspen EDR approach are found to be around 0.239 m3 and 0.839 m3, respectively.

High sour natural gas dehydration treatment through low temperature technique: Process simulation, modeling and optimization

Among the various fossil fuels, natural gas is a clean fuel because it has a less adverse impact on the environment compared to other energy sources. Natural gas emits less hazardous gases and less CO2 upon burning. Water, CO2, N2, H2S, and other contaminants could be present in raw natural gas, depending on its geographic location. The main issue among these contaminants is CO2, which decreases the calorific value of natural gas and corrodes pipes and process equipment. Absorption, adsorption, membrane separation, and cryogenic separation are the four main CO2 separation technologies. Cryogenic technologies for natural gas purification are environmentally friendly because they involve physical separation, and no harmful chemicals are required. Although cryogenic is an attractive alternative, it has some process limitations. The water must be removed before cryogenic separation because it can create piping blockage due to ice formation. The main goal is to remove water from natural gas at optimized conditions. The absorption technique employing triethylene glycol (TEG) as a solvent is the most widely used technology for dehydrating natural gas. Water extracts from natural gas as it passes over TEG, which acts as a dehydrating agent. The harmful effects of TEG on the environment are this technology's principal drawback. The current work investigates the dehydration of natural gas utilizing a low-temperature packed bed which could be an attractive alternative due to the absence of harmful chemicals. A thorough simulation analysis was carried out to learn more about the impact of the process parameter on the separation. The results showed that the pressure increase from 1 to 5 bar resulted in water removal from 25.4 to 83.7%. The optimum temperature and pressure for maximal water removal from natural gas were also determined. The maximum water was removed at 34 bar and −7.3 °C.