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The gas sweetening process is essential for removing harmful acid gases, such as hydrogen sulfide (H2S) and carbon dioxide (CO2), from natural gas before delivery to end-users. Consequently, chemical absorption-based acid gas removal units (AGRUs) are widely implemented due to their high efficiency and reliability. The most common solvent used in AGRU is monodiethanolamine (MDEA), often mixed with piperazine (PZ) as an additive to accelerate acid gas capture. The absorption performance, however, is significantly influenced by the solvent mixture composition. Despite this, solvent composition is often determined through trial and error in experiments or simulations, with limited studies focusing on predictive methods for optimizing solvent mixtures. Therefore, this paper aims to develop a predictive technique for determining optimal solvent compositions under varying sour gas conditions. An ensemble algorithm, Extreme Gradient Boosting (XGBoost), is selected to develop two predictive models. The first model predicts H2S and CO2 concentrations, while the second model predicts the MDEA and PZ compositions. The results demonstrate that XGBoost outperforms other algorithms in both models. It achieves R2 values above 0.99 in most scenarios, and the lowest RMSE and MAE values of less than 1, indicating robust and consistent predictions. The predicted acid gas concentrations and solvent compositions were further analyzed to study the effects of solvent composition on acid gas absorption across different scenarios. The proposed models offer valuable insights for optimizing solvent compositions to enhance AGRU performance in industrial applications. [ABSTRACT FROM AUTHOR]

This work focused on the solubility of ethane in three promising ionic liquids {1-Hexyl-3-methylimidazolium bis(trifluormethylsulfonyl) imide [HMIM][Tf2N], 1-Butyl-3-methyl-imidazolium dimethyl-phosphate [BMIM][DMP], and 1-Propyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl)-imide [PMIM][Tf2N]}. The solubilities were measured at 303.15 K to 343.15 K and pressures up to 1.4 MPa using a gravimetric microbalance. The overall ranking of ethane solubility in the ionic liquids from highest to lowest is the following: [HMIM][Tf2N] > [PMIM][Tf2N] > [BMIM][DMP]. The Peng–Robinson equation of state was used to model the experimental data using three different mixing rules: van der Waals one, van der Waals two, and Wong–Sandler mixing rules combined with the Non-Random Two-Liquid model. The average absolute deviations for the three mixing rules for the ionic liquids at the three temperatures were 4.39, 2.45, and 2.45%, respectively. Henry's Law constants for ethane in [BMIM] [DMP] were the highest (lowest solubility) amongst other ionic liquids studied in this work. The solubility ranking for the 3 ILs was confirmed by calculating their overall polarity parameter (N) using COSMO-RS. The selectivity of CO2 over C2H6 was estimated at three temperatures, and the overall ranking of the selectivity was in the following order: [PMIM][Tf2N] > [BMIM][DMP] > [HMIM][Tf2N] > Selexol. Selexol is an efficient and widely used physical solvent in gas sweetening. It has lower selectivity than the three ionic liquids studied. [PMIM][Tf2N], a promising solvent, has the highest selectivity among the three ILs studied and would, therefore, be the best choice if, in addition to carbon dioxide capture, ethane co-absorption was to be avoided. The enthalpy and entropy of solvation at infinite dilution were also estimated. [ABSTRACT FROM AUTHOR]

Liquid carry-over phenomenon, where liquid droplets escape with gas, is a prevalent operational challenge in gas–liquid separators. Liquid carry-over leads to foaming issue and performance reduction within separator downstream absorption processes. In order to ascertain whether liquid carry-over is inducing foaming within the gas sweetening process's absorption tower at Iraq's Khor Mor gas-condensate processing plant, this study initiated an evaluation of the liquid droplet size distribution in the gas product and gas/liquid separation efficiency of upstream Alpha, Bravo #1, Bravo #2, and Charlee separators that feed into the aforementioned tower by using the Horizontal Vessel and ProSeparator correlations in Aspen HYSYS v.11 software. The study revealed that Alpha and Bravo #2 experienced liquid carry-over issues. In response to these challenges, an innovative smart separator design, referred to as an adjustable separator, was proposed, employing the Arnold-Stewart semi-empirical procedure. This design allows for easy adjustment to accommodate changes in feed composition and operational conditions, mitigating the liquid carry-over problem. The smart design demonstrated a significant increase in gas/liquid separation efficiency for Alpha separator, improving by 31.11% under current conditions and 77.65% under future conditions. Similarly, under both current and future conditions, the smart design of Bravo #2 separator yielded an enhancement of 21.31% and 28.23%, respectively. These results suggest that the smart design can be considered an optimal solution for controlling liquid carry-over. This innovation not only maintains high gas/liquid separation efficiency but also prevents foaming, offering a robust solution for ensuring sustained operational performance and productivity in gas–liquid separation processes. [ABSTRACT FROM AUTHOR]

In the oil and gas industries, the reliability of pressurized components is essential for ensuring safety and continuous operations. The amine tower is a critical part of gas-treating refineries, responsible for gas sweetening. This study focused on conducting a fitness-for-service assessment of an amine tower experiencing hydrogen-induced cracking. The material conditions of the damaged tower were determined by examining a retired tower fabricated from the same heat number material. The assessment was carried out following the API 579-1/ASME FFS-1 guidelines, specifically utilizing sections 7 and 9 for level 3 assessments. Section 7 involves assessing the load-bearing capacity of the vessel, while also considering the dimensions of defects in the tower's formed head to evaluate crack-like flaws using the failure assessment diagram defined in section 9. This analysis determined that the damaged tower, containing the HIC defect measuring 2480 × 2480 mm with a depth of 16.1 mm, could safely withstand an internal design pressure of 8.963 MPa, taking into account welding residual stresses. The findings indicated that the damaged area fell within the acceptable region of the failure assessment diagram, thereby confirming the continued safe operation of the HIC-damaged amine tower. [ABSTRACT FROM AUTHOR]

Amine gas sweetening is the most used process in oil and gas industry to remove acid gases like H2S and CO2 from natural gas. This study highlights one of the main characteristics of amine gas sweetening process which has high energy requirements. In order to reduce the energy consumption of this process, a modification considered the process configuration has been suggested. This modification was investigated by Aspen HYSYS version 11 as a simulation tool. The case study used to show the benefits of the introduced modification in a giant natural gas sweeting plant in Egypt. The obtained results show that circulation of the side semi-lean amine stream from the regenerator to the absorption column leads to a reduction of the energy consumption of the considered plant by about 18% and a reduction of the reboiler duty by 12%. This effect has a great importance in case of limited steam production. Furthermore, the introduced modification decreases the utilities cost by about 11%. From these results, it is clear that the proposed modification is of high importance in decreasing the energy consumption which in turn increases the profits of the investigated plant. [ABSTRACT FROM AUTHOR]

Gas sweetening with an aqueous solution of diethanolamine is a crucial and common process in natural gas processing. However, the process, particularly in the solvent regeneration section, consumes a substantial amount of energy, significantly escalating the cost of gas. This paper presents a simulation and optimization of an existing natural gas refinery plant using a lean vapor compression method. The simulation results indicate that the current process requires 2.73 GJ/tacid gas for solvent regeneration, with exergy destruction of 14,120.59 kW in the solvent regeneration section. The total annualized cost for the current process is 11.68 M$. A modified scheme is proposed to address the issue of high energy consumption and the associated costs. The proposed scheme demonstrates significant improvements in the aforementioned parameters. Specifically, energy for solvent regeneration, exergy destruction in the solvent regeneration section, total annualized cost, and cost of gas are reduced by 16.12 %, 25.04 %, 20.97 %, and 20 % compared to the current process, respectively. These improvements enhance the thermoeconomic indexes, making the proposed scheme a viable and cost-effective alternative to the current process. [ABSTRACT FROM AUTHOR]

Removing sour gas from any suitable gas sweetening technology in a cost-effective and environmentally responsible manner is a major challenge. This paper discusses how to safely and economically dispose of small amounts of acid gases resulting from the amine sweetening process. A two-stage Claus desulfurization unit was studied and simulated to treat acid gases resulting from natural gas sweetening operations in Ras Gharib oil fields (Egypt). These acid gases are used as feedstock for the proposed plant to produce a valuable product, such as elemental sulfur, which is used as a raw material in many industries. Although many sulfur recovery techniques are available for various conditions and applications, the Claus process is a critical and widely used method for recovering elemental sulfur from gaseous hydrogen sulfide. This work represents the potential benefits of treating acid gases with high hydrogen sulfide content. In addition, operational variables that could affect sulfur production and sulfur recovery efficiency of the studied Claus unit were studied and optimized. Aspen HYSYS simulation software (version 9) was used to evaluate the economic aspects and optimize the operational parameters of the unit for producing sulfur from acid background gases. The results showed that the maximum sulfur production was achieved at a catalytic converter reactor temperature of 270 °C and 210 °C for the first and second catalytic reactor, respectively, with an air flow rate of 933.3 kg mol/h. The economic study of the proposed desulfurization unit showed that the Claus unit would be economically acceptable with an expected return on investment of approximately 10% and an average payback period of 10 years. Moreover, the introduced plant has a positive impact on the environment by reducing the concentration of hydrogen sulfide in the gas from 69.58 to 0.16%. [ABSTRACT FROM AUTHOR]

Liquefied petroleum gas (LPG) is one of the common fossil fuels that can be derived from natural gas or crude oil. In either case, it contains impurities such as H2S and CO2, which should be removed to obtain sweet liquified petroleum gas with a pure concentration of hydrocarbons such as ethane, propane, and butane. The most common method of gas sweetening process is by using amine compounds, which come in various types, each designed for specific and selective removal of acidic gases. In this study, methyldiethanolamine (MDEA) (42 wt.%) was used as a solvent to extract approximately 0.8% of H2S from sour LPG at a temperature of 40°C. The objective of this study focuses on simulating and optimizing the LPG sweetening unit using Aspen HYSYS V11 to investigate the different parameters that affect the separation of acidic gases and to achieve high profitability. The number of trays, circulation rates, temperature, mass and molar flow rates, and other parameters were studied to reduce the H2S concentration to 0% in the treated LPG stream. The sweetening process was proposed to produce LPG with high levels of specific preferred specifications such as calorific value and purity, in addition to being environmentally friendly. [ABSTRACT FROM AUTHOR]

Fermented meat products is the meat products with special flavor, color, texture and longer shelf life formed by a series of changes under natural or artificially controlled conditions by the action of microorganisms or enzymes. Fermented meat products is popular with consumers, but they are rich in protein and have a great potential for high levels of biogenic amines. Among them, histamine and tyramine are the most toxic. Consumption of tyramine-rich foods might cause headache, hypertension and other adverse reactions. Therefore, it is extremely necessary to control the tyramine content in fermented meat products. In this paper, the formation pathways, control methods and effects of tyramine in fermented meat products are reviewed. Among them, the main formation pathway is the decarboxylation of tyrosine by the action of decarboxylase, in addition to the existence of chemical pathways related to lipid oxidation products, while the more effective control methods are the addition of auxiliaries and the inoculation of fermentation agents. This paper aims to provid a theoretical support for reducing the tyramine content in fermented meat products and improving the safety of fermented meat products. [ABSTRACT FROM AUTHOR]

The research focuses on evaluating how well new solvents attract light hydrocarbons, such as propane, methane, and ethane, in natural gas sweetening units. It is important to accurately determine the solubility of hydrocarbons in these solvents to effectively manage the sweetening process. To address this challenge, the study proposes using advanced empirical models based on artificial intelligence techniques like Multi-Layer Artificial Neural Network (ML-ANN), Support Vector Machines (SVM), and Least Square Support Vector Machine (LSSVM). The parameters for the SVM and LSSVM models are estimated using optimization methods like Genetic Algorithm (GA), Particle Swarm Optimization (PSO), and Shuffled Complex Evolution (SCE). Data on the solubility of propane, methane, and ethane in various ionic liquids are collected from reliable literature sources to create a comprehensive database. The proposed artificial intelligence models show great accuracy in predicting hydrocarbon solubility in ionic liquids. Among these, the hybrid SVM models perform exceptionally well, with the PSO-SVM hybrid model being particularly efficient computationally. To ensure a comprehensive analysis, different examples of hydrocarbons and their order are included. Additionally, a comparative analysis is conducted to compare the AI models with the thermodynamic COSMO-RS model for solubility analysis. The results demonstrate the superiority of the AI models, as they outperform traditional thermodynamic models across a wide range of data. In conclusion, this study introduces advanced artificial intelligence algorithms such as ML-ANN, SVM, and LSSVM in accurately estimating the solubility of hydrocarbons in ionic liquids. The incorporation of optimization techniques and variations in hydrocarbon examples improves the accuracy, precision, and reliability of these intelligent models. These findings highlight the significant potential of AI-based approaches in solubility analysis and emphasize their superiority over traditional thermodynamic models. [ABSTRACT FROM AUTHOR]

In this research, gas sweetening process of the Iraq Majnoon refinery plant and its optimization scenarios were investigated using ASPEN HYSYS 8.4 and genetic algorithm optimization. First, values of optimization parameters such as the values of the population, generations and crossover for single and multi-objective optimizations were obtained. The effect of temperature and molar flow of feed gas and make-up water on concentration of CO2 and H2S in the sweet gas were studied. The result showed that with increasing the temperature and molar flow of feed gas, the concentration of CO2 and H2S in the sweet gas was increased. The single and multi-objectives’ optimizations of process were carried out with minimizing the concentration of CO2 and H2S, minimizing the consumed energy of stripper and overall consumed energy of plant including energy of stripper and cooler. It was observed that for optimization of concentration of CO2 and H2S, mole fraction of CO2 and H2S decreased to minimum amounts of 5.52 e-4 and 6.84 e-9 between optimization data sets. Also, it was found that with increasing the number of objective functions of the optimization, the ability of the algorithm to reduce the amount of the objective functions decreases, because genetic algorithm should consider more constraints with increasing the number of objective functions. The novelty of this research was a comprehensive study of gas sweetening process optimization with single to four objectives.

Pyrolysis of waste tyres produces harmful hydrogen sulfide and other mercaptan compounds as by-products. The current study is concerned with the purification of hydrogen-rich pyrolysis gas from hydrogen sulfide gas that is present in a great amount (up to 5.1% mol at 420 °C), and mercaptans that are also problematic impurities. The method proposed is absorption by alkanolamines which is one of the most economical methods applied in natural gas sweetening. However, it has not been adopted in waste tyre pyrolysis gas purification yet. Two organic absorbents were tested, diethanolamine (DEA), N-methyldiethanolamine (MDEA) as well as theirs blends, at various concentrations. The application of 30 wt% DEA in water reduced H 2 S emission by 98%. In turn, 40 wt% MDEA aqueous solutions reduced H 2 S emission by 97%. The best results were produced when 30 wt% DEA was mixed with 40 wt% of MDEA (1:1 vol ratio) which allowed a removal of 99% of H 2 S from the pyrolysis gas. Moreover, the maximum H 2 S emission was 7 ppm, and a level below 5 ppm was kept for 99% of experiments duration. Finally, the application of this mixture also reduced significantly the concentrations of other sulfur-containing compounds such as methyl mercaptan and carbonyl sulfide (a minimum of 98%), ethyl mercaptan (∼90%), and carbon disulphide (by more than 99%). Thus, aqueous solvent mixture of 30 wt% DEA with 40 wt% of MDEA (1:1 v/v) can be recommended as a potential desulfurization method for waste tyres pyrolysis gas. • Pyrolysis gas is a valuable fuel, but it needs pre-treatment focused on desulfurization. • Raw pyrolysis gas contains high concentrations of H 2 S (up to 5.1%) and mercaptans. • Solutions of alkanolamines can be applied in desulfurization of pyrolysis gas. • DEA, MDEA and as their blends are effective in cleaning pyrolytic gas from H 2 S (>97%). • Blends of DEA/MDEA can also remove other sulfur containing compounds. [ABSTRACT FROM AUTHOR]

As the core process of natural gas purification plant, natural gas sweetening directly affects the production efficiency and product quality of the purification plant. However, process modeling based on sulfur content prediction presents challenges in adaptability and accuracy. To tackle this, a machine learning‐based modeling approach is proposed that integrates an adaptive immune genetic algorithm with random forest (RF) to intelligently select process features as input variables for RF modeling. The industrial result indicates that the proposed method is able to remove interfering variables and adaptively achieve optimal model precision for different scenarios. It offers a novel research instrument for product quality monitoring in natural gas sweetening plants. [ABSTRACT FROM AUTHOR]

Water-lean solvents are thought to deliver promising benefits including enhanced mass transfer properties, increased absorption capacities, and lower solvent regeneration heat duties in the natural gas sweetening process. Acid gas (H2S and CO2) removal is an essential piece of the natural gas value chain due to its corrosive effect on pipeline and process equipment, its impact on the environment, and its reduction in methane heating value. A number of solvents have been used for this process in the past. However, the low acid gas pickup, high cost per unit separation, and high regeneration heat duties form the basis for which we considered a water-lean solvent in this study. This study employs ASPEN HYSIS V12.1 to model the natural gas sweetening process of a hypothetical non-associated sour gas well with a novel water-lean solvent (50% wt. MDEA + 30% wt. DIPA + 15% wt. DMSO + 5% wt. H2O). Theoretical solvent screening was carried out to select the most promising water-lean solvent, following a flowsheet design, modeling, and result validation. The process economic analysis was carried out using Aspen Process Economic Analyzer to determine the unit separation cost and profitability indicators. The results show that the solubility of CO2 was found to be lower in water-lean solvents. The mass transfer did not seem to improve. This was generally difficult to take into consideration and properly assess in Aspen as there are no literature data with DMSO to fit the model parameters. DMSO reacts with H2S, leading to a loss of solvent. However, the mass transfer improved with the physical co-solvent, and the acid gas solubility decreased, resulting in more solvent consumption and impacting the capital expenditure. Economic analysis showed that the equipment cost of the proposed solvent is 1.4 M USD/yr higher than that of the aqueous MDEA commercially in use. As such, it is not considered economically viable. [ABSTRACT FROM AUTHOR]

• Effect of the operating parameters of a sweetening unit on CO 2 recovery efficiency has been studied and evaluated. • An equation relating the studied operating parameters and their interaction with CO 2 recovery efficiency was modeled. • Numerical optimization in Design Expert program is used to achieve the goal of maximizing CO 2 recovery efficiency. Amine processes are the advanced technology available today for the removal of carbon dioxide (CO 2) and hydrogen sulfide (H 2 S) acid gases. Methyldiethanolamine (MDEA) is a well-known tertiary amine used selectively for the removal of carbon dioxide from natural gas. There are many parameters that can affect the efficiency of separating these acid gases from natural gas. In this paper, we have studied, modeled, and optimized different operating parameters of sour gas feed and MDEA solution which affect the CO 2 recovery efficiency from an existing sweetening unit. These operating parameters are the sour gas feed temperature and pressure, volume ratio (%) of carbon dioxide in the feed gas, amine inlet temperature, and amine circulation rate. Actual data were collected from an industrial CO 2 sweetening unit over one year. These data were used to study the effect of the studied operating parameters on the recovery efficiency of CO 2 from the sweetening unit. All studied operating parameters were found to have an impact on the recovery efficiency of the removed gases. A response surface methodology approach was used in Design-Expert software version 13 to model the relationship between considered operating parameters and CO 2 recovery efficiency. In addition, Design Expert numerical optimization has been used to maximize CO 2 recovery efficiency. The results showed that the optimal range of sour gas feed temperature is 34.71 to 45.56 °C, sour gas feed pressure is 8.32 to 10.04 barg, the volume ratio (%) of carbon dioxide in the sour gas feed is 8.51 to 10.15, the temperature of the amine is 38.03 to 43.96 °C, and the amine circulation rate is 788.39 to 1122.35 m3/h. The presented work can be considered as a guideline for increasing the recovery efficiency of CO 2 for both new and existing sweetening units. [ABSTRACT FROM AUTHOR]

As the most mature natural gas sweetening process, absorption has always been improved to meet the separation requirement. Recently, ultrasonic irradiation has been proposed as a technique that can intensify CO2 absorption. However, further studies are still required, particularly focusing on the sonochemical effect. Since the influence of the sonochemical effect on the reaction pathway is still debatable, attention must be given to verifying the influence of ultrasonic irradiation on the chemical reactions of CO2 absorption. Hence, this work aims to evaluate the influence of  O H ˙  radicals generated by the sonochemical effect on the chemical reactions involved during CO2 absorption using promoter-free methyldiethanolamine (MDEA). For the evaluation, various samples under irradiated and non-irradiated conditions are analyzed using the HPLC characterization technique. The results show that the hypothesis of changing the reaction pathway due to the presence of the sonochemical effect is invalid. However, it can accelerate the generation of hydroxyl radicals ( O H ˙ ) via water sonolysis. Thus, the origin of sonochemistry in aqueous solutions is defined as water sonolysis. The analysis of the CO2 absorption rate also demonstrates the presence of accelerated chemical reactions (contributed by the  O H ˙  radicals), which could potentially make the slow kinetic MDEA more practical for industrial application. [ABSTRACT FROM AUTHOR]

An intelligent optimization of multistage gas permeation layouts is required to achieve high product gas purities and high product recoveries at the same time in gas separation technologies. In this work, a superstructure-based mathematical model for the optimization of CO 2 removal in three applications including post-combustion CO 2 capture, natural gas sweetening and biogas upgrading is designed. A typical polymeric membrane prepared within the BIOCOMEM project, with high CO 2 permeance, CO 2 /N 2 selectivity of 25, and CO 2 /CH 4 selectivity of 7.9 is studied to assess the potential of this membrane at a real industrial scale. Using a superstructure-based model, operating conditions, driving force distribution along each membrane stage, the use of feed compression and/or permeate vacuum, the number of stages and recycle options are simultaneously optimized. The techno-economic analysis of all three applications is then carried out and the most promising membrane-based process configuration was chosen. The multi-stage membrane process is investigated in terms of capture cost, energy consumption, and membrane area. The results revealed that high purity and recovery at a minimum cost could be achieved by the three-stage process in post-combustion CO 2 capture and natural gas while in biogas upgrading the two-stage configuration exhibited the best performance. It was found that a reduction in capture cost to around 42 €/tCO 2 is possible in post-combustion CO 2 capture if membranes with a selectivity of 50 and the same permeation flow are developed. [Display omitted] • A superstructure-based optimization approach for gas separation was designed. • Superstructure applied to CO 2 removal from flue gas, natural gas and biogas upgrading. • Techno-economic feasibility analysis on membrane system for CO 2 separation. • Approach was investigated in terms of cost, membrane area and power consumption. • The power consumption and capture cost are a strong function of CO 2 purity. [ABSTRACT FROM AUTHOR]

The results of the oxidative desulfurization process (combination of straight-run gasoline fraction and gas condensate oxidation with subsequent rectification) are presented. It is shown for the first time that it is possible to obtain a gasoline fraction with ultra-low sulfur content by oxidation and rectification of gas condensate. Optimum conditions have been selected for the process of sulfur compounds oxidation and subsequent rectification of gas condensate. [ABSTRACT FROM AUTHOR]

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The removal of acid gas impurities from synthesis gas or natural gas can be achieved using several physical solvents. Examples of solvents applied on a commercial scale include methanol (Rectisol), poly(ethylene glycol) dimethyl ethers (Selexol), n-methyl-2-pyrrolidone (Purisol), and propylene carbonate (Fluor solvent). Continuous Fractional Component Monte Carlo (CFCMC) simulations in the osmotic ensemble were used to compute the Henry coefficients of the pure gases CO 2 , CH 4 , C 2 H 6 , CO, H 2 , N 2 , N 2 O, and H 2 S in the aforementioned solvents. The predicted Henry coefficients are in good agreement with the experimental results. The Monte Carlo method correctly predicts the gas solubility trend in these physical solvents, which obeys the following order: H 2 S > CO 2 > C 2 H 6 > CH 4 > CO > N 2 > H 2 . The gas separation selectivities for the precombustion process and the natural gas sweetening process are calculated from the pure gas Henry coefficients. The CO 2 /N 2 O analogy is verified for the solubility in these solvents. [ABSTRACT FROM AUTHOR]

Natural gas processing is currently facing economic and environmental challenges due to abrupt changes in oil prices and the development of an alternate source of energy. Therefore it is essential to optimize the processing unit to make it profitable and environmentally friendly. Sustainable optimization of an industrial natural gas treatment plant is carried out using the NSGA-II algorithm for the methyl diethanol amine (MDEA) process to optimize CO 2 removal along with payback period and damage index. This multi-objective optimization study includes seven decision variables such as temperature and pressure of feed gas, feed flow rate, temperature and pressure of regenerator feed, lean amine temperature, and MDEA concentration. Three separate two-objective optimization study problems are developed and applied for retrofitted case and base case studies. Two different ProMax models are developed and validated the model by using actual plant data. All the retrofitted cases and base cases are solved and the Pareto optimal fronts are obtained. Trade-offs between different objectives are illustrated for all the problems. The lean vapor compression process can facilitate maximum H 2 S removal of 99.75% and maximum CO 2 removal of 98.52% simultaneously by maintaining a DI value of 476. TOPSIS method is used to rank and find the best optimal solution. Optimization study for uncertain CO 2 concentration (4%mole) in the feed gas is also analyzed and compared with normal feed conditions. The machine learning approach is used to obtain the predictions of selected objective functions for all the problem cases using the decision tree method. [Display omitted] [ABSTRACT FROM AUTHOR]

Corrugated (SMV‐style) static mixers are industrially important for process intensification and can promote gas–liquid mass transfer in processes such as sour gas sweetening. Current correlations for pressure loss are limited to Reynolds numbers (Re) below 40 000, far below the ranges encountered in natural gas systems (105 < Re < 107). An experimental and numerical study of pressure drop across multiple corrugated mixers in the range of 104 < Re <2 × 105 encompassing different configurations (aligned, rotated), pipe diameters (1–4 in.), and sand grain surface roughness values (10–5000 μm) is reported here. Our previous correlation for pressure loss across a single corrugated element is shown to be extendable to multiple corrugated mixing elements. Through the inclusion of mixer tortuosity (τ), porosity (ε), and macro‐scale (geometric) wall roughness (e), the correlation also matches historical pressure drop data (at different τ, ε) reported in literature, thereby demonstrating the utility of these variables as parameters that can help optimize mixer performance. Experiments and computational fluid dynamics (CFD) modelling revealed that the rotated configuration increased the residence time by up to 13% in comparison to the aligned configuration. This may have implications on the selective absorption of sour gas components that are based on fast kinetics. In addition, the role of wall roughness (both pipe housing and mixer) was demonstrated to be significant in this study (accounting for 55% of the pressure losses) and must be accurately accounted for when scaling laboratory measurements. [ABSTRACT FROM AUTHOR]

With sodium dodecyl sulfate(SDS) and coconut amine polyoxyethylene ether as the main surfactants, propanol as the cosurfactant, white oil as the oil phase, NaCl solution as the water phase, and a small amount of biosurfactant, a recyclable microemulsion oil-based drilling cuttings degreaser was prepared, and its performance was evaluated・ The recovery rate, degreasing effect, cycle stability, wetting characteristics and interfacial tension of microemulsion degreaser were investigated・ The results show that the recovery rate of oil remover is more than 90% when the mass ratio of oil remover to oil-based drilling cuttings is 3 : 1 ・ The oil content of drilling cuttings can be reduced to below 2% after cleaning drilling cuttings with microemulsion degreaser at normal temperature, and 0. 83% when cleaning cuttings at 50 °C ・ The degreaser still maintains good oil removal effect after being recycled for 5 times・ The prepared microemulsion degreaser has good wettability reversibility, and has low interfacial tension with white oil and kerosene ・ The microemulsion type degreaser is easy to prepare, has good degreasing effect, and can be recycled for many times, which can efiectively solve the problem of waste and environmental pollution of degreaser in oil-based drilling cuttings degreasing process. [ABSTRACT FROM AUTHOR]

The present paper focuses on the efficiency enhancement of the energy-intensive natural gas (NG) sweetening process in the context of upstream natural gas production. A bi-level heat integration scheme is proposed including direct recycling of available high-temperature waste heat and harnessing the excess low-temperature waste heat in an optimized organic Rankine cycle (ORC) for power production. The energy performance of the whole model was studied under a range of possible reservoir conditions. A particle swarm optimization (PSO) algorithm was adopted to simultaneously optimize the parameters of the heat recovery network as well as the ORC cycle parameters. Finally, in order to account for the impact of perturbations of the heat source and sink, an off-design performance analysis was conducted using real-time data from an industrial plant. The proposed integration methodology was found to be effective across most of the reservoir conditions covered in this study. At optimal integration, a reduction of 40% up to 100% in heating requirements of the amine process was reported, as well as a net electricity production of 30% up to 190% of the electrical demand of the background process. The use of propane (R290) as a working fluid resulted in the highest energy output, whereas higher carbon number fluids allowed a better energy/working pressure trade-off. The off-design analysis allowed for the quantification of the impact of operational fluctuations of the background process on integration performance. Energy savings resulting from direct heat integration were found to range from 68% up to 103% of the expected design value, whereas the ORC net energy output respective to the use of R290, R600a, and R601a was found to range from 60% to 132%, 47% to 142%, and 52% to 135%. [ABSTRACT FROM AUTHOR]

Introduction: Unit risk management is a critical component of gas refining management, as risks that are not well-managed may lead to trip production failures. The present study aimed to provide a structural model for investigating the role and effect of different variables on stopping the gas production process in the gas refinery. Material and Methods: This study was a retrospective cross-sectional and systematic analysis, which was carried out on key risks in the trip gas sweetening unit in a gas refinery industry located in Asaluyeh, Iran. The systems analysis was applied by using Fishbone Diagram, and then data modeling was prepared by Structural Equation Modeling (SEM) for an incident that occurred during gas sweetening production. Tools for the data analysis included the SPSS 24 and Smart PLS 2 software. Results: Results of this research indicate that “Environment Risk” with a path coefficient of 0.943 and T- Value of 103.791; “Cost Risk” with a path coefficient of 0.937 and T- Value of 95.168; “Implementation of management system Risk” with a path coefficient of 0.847 and T- Value of 35.23; “Accident Risk” with path coefficient of 0.577 and T- Value of 25.410; “Time Risk” with path coefficient of 0.758 and T- Value of 15.121; “Human Error Risk” with path coefficient of 0.712 and T- Value of 11.215 had the most important coefficients of the paths respectively, that are effective in stopping production concerning other risks. Also, by comparing the path coefficients of the risks we can see that the impact of each of the risks on stopping production is different. Conclusion: The findings of the present study revealed that a combination of variables can affect stopping production in the gas industry. Therefore, the role of these risks in losses in the refinery system should be investigated.

In order to investigate the effect of nanoparticles on CO2 capture in aqueous solutions of 2-diethylaminoethanol (DEEA) and N-methyldiethanolamine (MDEA), nanofluids with different types and sizes of nanoparticles were prepared by two-step method. The relationship between the absorption ca- pacity, absorption rate, circulating desorption capacity of alcohol amine aqueous solution and nanoparticles was investigated. The results show that the absorption and desorption of CO2 by DEEA and MDEA solu- tions are enhanced by adding TiO2, SiO2, and grapheme (GO) nanoparticles improved the mass transfer between gas and liquid. The 30% DEEA-0.05% 25 nm TiO2, 30% MDEA-0.05% 40 nm TiO2, 30% MDEA-0.06% GO systems increased the CO2, absorption by 9. 86%, 11.26% and 13.8%; the absorption rate was increased by 33.43%,49.72% and 39.23%; the desorption amount was increased by 10.72%, 9.19% and 26.66%. By 13C NMR and FTIR characterization, it was found that the addition of nanoparticles improved the mass transfer between gas and liquid, and no new substances were produced. [ABSTRACT FROM AUTHOR]

The sweetening units are the most important in natural gas processing. Packed bed absorption columns are widely used in the sweetening process; however, their operation and control are not simple due to their highly non-linear behavior derived from their distributed nature and interaction between multiple physical phenomena. In this work, two robust model-based control schemes are implemented to regulate the CO2 concentration at the outlet of a packed bed absorption column in the gas sweetening process. The model of an industrial-scale absorption column and the structure of the controllers, i) control based on modeling error compensation (MEC) ideas, and ii) nonlinear model predictive control (NMPC) are described. Numerical results show that the proposed robust model-based controllers can regulate the controlled variable to the desired reference despite external disturbances, set-point changes, and uncertainties in the absorption column model. [ABSTRACT FROM AUTHOR]

According to the viscoelastic surfactant to acidizing and fracturing fluid system， the interaction of a new type of dipoly-quinoline quaternary amine salt inhibitor and the influence of different salt solutions on its viscosity temperature performance and mechanism were studied.The experimental results show that the viscoelastic surfactant as a diversion acid system has no effect on the inhibition efficiency of the corrosion inhibitor, and the diphenylquinoline quaternary amine salt corrosion inhibitor reduces the high temperature resistance of the viscoelastic surfactant. Low concentration of inorganic salt solution has no effect on viscoelastic surfactant viscosity, but high concentration of bivalent salt solution can significantly improve the high temperature resistance of viscoelastic surfactant solution. In the presence of high concentration of CaCl2, the high temperature resistance of the viscoelastic surfactant containing quaternary amine acidizing corrosion inhibitor was improved. [ABSTRACT FROM AUTHOR]

The gas sweetening process removes hydrogen sulfide (H2S) in an acid gas removal unit (AGRU) to meet the gas sales' specification, known as sweet gas. Monitoring the concentration of H2S in sweet gas is crucial to avoid operational and environmental issues. This study shows the capability of artificial neural networks (ANN) to predict the concentration of H2S in sweet gas. The concentration of N-methyldiethanolamine (MDEA) and Piperazine (PZ), temperature and pressure as inputs, and the concentration of H2S in sweet gas as outputs have been used to create the ANN network. Two distinct backpropagation techniques with various transfer functions and numbers of neurons were used to train the ANN models. Multiple linear regression (MLR) was used to compare the outcomes of the ANN models. The models' performance was assessed using the mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R2). The findings demonstrate that ANN trained by the Levenberg–Marquardt technique, equipped with a logistic sigmoid (logsig) transfer function with three neurons achieved the highest R2 (0.966) and the lowest MAE (0.066) and RMSE (0.122) values. The findings suggested that ANN can be a reliable and accurate prediction method in predicting the concentration of H2S in sweet gas. [ABSTRACT FROM AUTHOR]

The applications of triethylenediamine in various fields are introduced・ The synthesis processes of triethylenediamine are presented, such as alcohol-amine dehydration, cyclization of piperazine and its derivatives, deamination of ethylenediamine and others ・ The advantages and disadvantages of each process are compared and the reasons why the reaction systems are mostly fed as aqueous solutions are explained ・ Benefiting from the high yield, low cost of raw materials and environmentally friendly process of alkanolamine dehydration, it is pointed out that this synthesis process should be the key direction for the future development of triethylenediamine. [ABSTRACT FROM AUTHOR]

[Display omitted] • CMS hollow fiber membranes with high CO 2 affinity were prepared via an oxygen-doped strategy. • The CMS hollow fiber membrane exhibited a high CO 2 /CH 4 separation factor of 89.6 when fed with 10 % CO 2 -90 % CH 4 at 30 bar. • A long-term stability test over 90 h at 20 bar with 500 ppm C 7 shows potential for natural gas sweetening. Natural gas is considered one of the most attractive low carbon energy sources while the separation of CO 2 is a crucial process for the natural gas purification. Herein, cellulose-based carbon molecular sieve (CMS) hollow fiber membranes with high CO 2 affinity capability were fabricated through a post-treatment strategy of hydrogen-induced reduction followed by oxygen-doped modification (H-O treatment), and show good potential for high pressure natural gas purification. The CMS membranes were reduced by H 2 at high temperatures (500–600 °C) to form active sorption sites in the carbon matrix, and subsequently chemically absorbed O 2 to generate oxygen-containing functional groups, which are favorable for CO 2 adsorption and diffusion. After being treated at 600 °C (CMS-600), the CMS membrane presented a high CO 2 adsorption capacity of 62.78 cm3/g (298 K). As a result, the CO 2 permeability was enhanced from 264 to 1125 Barrer, with approximately 400 % improvement. Moreover, mixed gas separation performances (CO 2 /N 2 and CO 2 /CH 4) were investigated at high pressure and impurities feedings. The CMS membrane exhibited a remarkable CO 2 /CH 4 separation factor of 104 when operated at 20 bar and 500 ppm heptane existed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Techno-economic assessment of flare gas to gasoline by membrane unit conducted. • Membrane-based GTL reduces total carbon emissions by 23.3% versus conventional processes. • Total capital investment in membrane-based GTL decreases by 13% versus the conventional process. • GTL Production cost is lowered by 11.8% with Membrane-based GTL. • 200% Permeability enhancement improves membrane-based sweetening unit production cost versus conventional process. This study focuses on the techno-economic comparison of flare gas from an industrial stream valorisation into liquid fuels, comparing conventional gas-to-liquid (GTL) and membrane-based processes. Both processes encompass flare gas sweetening, synthesis gas production, and FT synthesis units. Integration of membrane-based GTL could decrease the overall liquid fuel production by 1.5%, with power requirements 47.3% higher and lower overall energy and steam demand of 25.8% and 21% respectively. The initial analysis indicates a 23.3% decrease in total carbon emissions for the Membrane-based GTL process compared to the Conventional GTL process. The Membrane-based GTL process demonstrates a potential 13% reduction in total capital investment and an 11.8% decrease in production cost for liquid fuel products, coupled with a remarkable 22.5% higher return on investment. Moreover, the payback period in the membrane-based GTL process is reduced by approximately 20.9%. In the membrane-based gas sweetening unit, the total capital investment and production costs increase by approximately 5%. In comparison, the membrane-based process for the FT unit offers a cost-saving approach of around 10.4%. Hence, the incorporation of membranes throughout the process will yield substantial profitability. Upon conducting an in-depth analysis of the flare gas sweetening unit, it becomes evident that enhancing permeability by over 200% could potentially reduce the production cost of the sweetening unit. Consequently, this renders it more preferable and lucrative than the amine process. [ABSTRACT FROM AUTHOR]

Poor interfacial compatibility is the most common issue inhibiting performance enhancement in mixed matrix membranes (MMM) for gas and liquid separations. To address this issue, we fabricated highly selective and permeable inter-crosslinked mixed matrix membranes (IcMMMs) based on carboxylic-acid functionalized polymer of intrinsic microporosity-1 (CPIM) containing up to 30 wt % triptycene-isatin polymer porous network (PPN) particles. Polymer-filler inter-crosslinking is accomplished via thermal decarboxylation at 200 °C, which is the lowest temperature this reaction has been found to occur in the literature. This low temperature circumvents potential issues with degradation of porous supports or gutter layer materials, and thus enables these materials to be integrated into traditional membrane processes. The resulting IcMMMs exhibit gel fractions above 90 %. Beyond IcMMMs, membranes based on neat CPIM, thermally crosslinked CPIM, as well as non-crosslinked CPIM-PPN mixed matrix membranes were fabricated to elucidate the individual and synergistic effects of filler inclusion and thermal treatment. In addition to showing upper bound permeability-selectivity performance, IcMMMs also exhibit an almost unprecedented stability against plasticization upon extended exposure to CO 2 up to 50 atm or above. This study shows that crosslinking across the polymer-filler interface is the key feature to achieve simultaneous enhancement in permeability, selectivity, and stability. To elucidate the molecular mechanism of these enhancements in the IcMMMs with respect to the baseline materials, permeability was broken into its sorption and diffusion contributions and an energetic analysis of sorption was performed. The low cost of PPNs coupled with the mild crosslinking temperature make this approach highly scalable, resulting in materials exhibiting high rigidity and structural stability with the potential to excel in aggressive separations, such as organic solvent separations or high-CO 2 content, high-pressure natural gas sweetening. [Display omitted] • Highly selective and stable inter-crosslinked MMMs were synthesized. • Polymer-filler thermal crosslinking leads to superior plasticization stability. • Thermal crosslinking was achieved at temperatures as low as 200 °C. • Inter-crosslinked MMMs show defect-free behavior up to 30 wt % PPN loading. • The roles of physical and chemical polymer-filler interactions were elucidated. [ABSTRACT FROM AUTHOR]

Membranes with a stable performance during the natural gas sweetening process application are highly demanded. This subject has been immensely explored due to several challenges faced by conventionally used polymeric membranes, especially the high tendency of plasticization and physical aging. In this study, polysulfone (PSf) hollow-fiber membrane was formulated and tested for its application in natural gas sweetening based on several compositions of CO2/CH4 mixed gas. The effects of operating conditions such as pressure, temperature and CO2 feed composition on separation performance were analyzed. The findings showed that the formulated membrane exhibited decreasing CO2 permeation trend with the increase in pressure. Conversely, the increase in operating temperature boosted the CO2 permeation. High productivity can be attained at higher operating temperatures with a reduction in product purity. Interestingly, since PSf has higher plasticization pressure, it was not affected by the change in CO2 percentage up to 70% CO2. The experimental study showed that the membrane material formulated in this study can be potentially evaluated at the field stage. Longer testing duration is needed with the real feed gas, appropriate pre-treatment based on the material limitations, and optimum operating conditions at the site to further confirm the membrane's long-term lifetime, resistance, and stability. [ABSTRACT FROM AUTHOR]

In natural gas (NG), significant amounts of hydrogen sulfide (H2S) and carbon dioxide (CO2) are the most menacing contaminants that cause degradation of the purity of fuel. We considered fluorine-functionalized MOFs and employed cheaper and faster computational simulation techniques to understand the adsorption process. Hence, this includes structural optimization of newly designed fluorine-functionalized MOF with Density Functional Theory (DFT) and further Grand Canonical Monte Carlo (GCMC) simulation at room temperature on those MOFs for understanding in detail the adsorptive separation process on sour gases. However, the main emphasis has been made on the adsorptive separation of H2S gas from sour gas. Eventually, the fluorination of organic ligand in [(SiF6)Ni(1,2-di(pyridin-4-yl)ethyne)2] MOF has resulted in an excellent H2S/CO2 separation performance from NG because of the different geometrical isomers. The cis isomer of 1,2-di(pyridin-4-yl)ethyne as ligand in MOF, i.e., SIFSIX-Ni-dpe-3-cis, shows a high CO2 affinity than H2S; on the contrary, the trans isomer of 1,2-di(pyridin-4-yl)ethyne as ligand in MOF, i.e., SIFSIX-Ni-dpe-3-trans, has H2S selective over CO2 and CH4. So, the resulting affinity variation indicates that structural variation by the stereochemistry of ligands in MOF plays a significant role in NG purification, which is further validated through detailed molecular simulation analysis. [ABSTRACT FROM AUTHOR]

The natural gases produced from underground reserves may contain sour gases such as H2S and CO2. If the amount of these gases is greater than the standard level, it will be harmful to humans and the environment. Hence, it appears important to accurately determine the concentration of H2S and CO2 in various equipment/units of a natural gas sweetening plant. In this study, a new connectionist approach is introduced to obtain the concentration of outlet acid gases of the sweetening tower of the South Pars gas refinery (in Iran), by utilizing a conventional connectionist tool optimized by an imperialist competitive algorithm (ICA). This ICA strategy is applied to optimize the weights, biases, and number of neurons of the artificial neural network (ANN) model. The input parameters in this modelling strategy include time, the amount of H2S in the output amine, the flow rate of input sour gas, the temperature of sea water for cooling, the mass flow rate of low‐pressure steam to the amine–amine heat exchanger, and the flow rate of input amine. The performance of the hybrid deterministic tool, ANN‐ICA, is compared with the ANN‐back propagation (BP) method. The coefficient of determination and mean squared error to forecast the concentration of output H2S are 0.8931 and 0.0125 for the ANN‐BP algorithm and 0.9057 and 0.0104 for the ANN‐ICA algorithm, respectively. These statistical values are 0.8428 and 0.0001 for the ANN‐BP model and 0.9307 and 0.000 05 for the ANN‐ICA model, respectively, while predicting output CO2 concentration. The results confirm that the ANN‐ICA is a more reliable approach, compared to ANN‐BP, to forecast the concentration of acidic gases leaving the absorption tower. [ABSTRACT FROM AUTHOR]

With the anticipated rise in global demand for natural gas (NG) and liquefied natural gas (LNG), sour gas reserves are attracting the attention of the gas industry as a potential resource. However, to monetize these reserves, sour natural gas has to be sweetened by removing acid gases (carbon dioxide and/or hydrogen sulfide) before liquefaction. The solidification of these acid gases could be the basis for their separation from natural gas. In this study, a state-of-the art solid-vapor (SV) separation unit is developed for removal of acid gases from methane and simulated using a customized Aspen Plus operation unit. The operating principles and conditions, mathematical model, and performance results are presented for the SV unit. Further performance analyses, means of optimization and comparisons to conventional methods used by the industry were studied. Results showed that for similar sweet gas purity, the developed SV unit consumes only 27% of the energy required by the amine sweetening unit. Furthermore, it saves on capital costs, as it requires less equipment and does not suffer from high levels of corrosion. [ABSTRACT FROM AUTHOR]

BACKGROUND: Sulfolane, an industrial solvent commonly used for sweetening natural gas, has recently emerged as a contaminant of concern in Alberta because of its widespread detection around many gas processing sites. In the work reported in this paper, the aerobic biodegradation of sulfolane by Pseudomonas strain or Archaea strain and mixed bacterial cultures was studied. The evaluation was furtherly conducted using Pseudomonas which had been acclimated to water contaminated with sulfolane. The impacts of co‐contaminant, initial sulfolane concentration and soil content on biodegradation of sulfolane using acclimated Pseudomonas were also investigated. RESULTS: The results showed that Pseudomonas degraded sulfolane at a rate of 2.03 mg L−1 h−1 while Archaea strain degraded sulfolane at a rate of 0.04 mg L−1 h−1. Pseudomonas and Archaea inoculated with aquifer sediments containing indigenous microbes achieved a higher sulfolane degradation rate. Acclimation of Pseudomonas to sulfolane environment sufficiently mitigated the lag period before the onset of the biodegradation process. CONCLUSIONS: Pseudomonas is a good candidate for aerobic biodegradation of sulfolane in groundwater. Aerobic biodegradation of sulfolane by Pseudomonas can be significantly enhanced through inoculation with sulfolane‐contaminated sediments or acclimatization to sulfolane environment. © 2022 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The separation of carbon dioxide and methane is vital for biogas upgradation and natural gas sweetening applications. Membrane separation is one of the techniques used for CO2 and CH4 separation for biogas upgradation and natural gas sweetening owing to its energy efficiency, low capital cost, portable, and ease of operation. Polymer membranes and inorganic membranes have a trade-off relationship between permeability and selectivity. A new class of membranes known as Mixed Matrix Membranes (MMMs) is being explored to overcome this trade-off by dispersing inorganic fillers in the polymer matrix. However, the addition of filler poses new interfacial morphological difficulties, such as poor dispersion, very strong interaction between filler and polymer, and formation of voids. These challenges can be tackled by suitable choice of filler and polymer, functionalization of filler and polymer, polymer blending. The hybrid membranes separation process or use of two or more strategies can lead to the formation of defect-free membranes with improved separation performance. In this review article, we provide a concise literature review and analysis of the strategies for improving the transport properties of MMMs based on MOF as filter materials for CO2/CH4 separation. [ABSTRACT FROM AUTHOR]

The selective removal of acid gases using amine-based solutions is a significant process in the petroleum and natural gas industries. This work investigates the effectiveness of two common chemical solvents of Methyl Diethanolamine (MDEA) and Diethanolamine (DEA) and the blends of them with different mass concentration and circulation rate to absorb H2S and CO2 from natural gas in an existing industrial process plant in Phase I of the South Pars Gas Complex (SPGC) located in Persian Gulf region. This sweetening unit was simulated for H2SCO2MDEAH2O and H2SCO2DEAH2O systems incorporated into the Amine Package in the Promax simulator. Sensitivity analyses were performed on circulation rate (140–350 m3/h for MDEA and 300–520 m3/h for DEA), concentration (30–65 wt.% for MDEA and 30–40 wt.% for DEA) of amine solution and the MDEA to DEA ratio (eight different cases) which are the main factors improving process performance. The effect of these factors has been separately studied on the parameters such as acid gas content in the sweetened gas, reboiler duty, acid gas loadings, amine carryover and pH. The results confirmed that higher solvent concentration and circulation rate are beneficial to the sour gas absorption process. However, they require greater corresponding energy to regenerate rich-loaded solution in the reboiler. It enhances the operational costs. Based on the results, the optimal concentration and flow rate of MDEA and DEA solvents was obtained at 40 and 32 wt.% and 150 and 350 m3/h, respectively.

H 2 S is a highly toxic, flammable gas that poses risks to health, the environment, and industrial infrastructure. Zeolites, with their high porosity, offer a promising solution for its removal. This study employs density functional theory (DFT) to investigate the adsorption behavior of H 2 S within the Li-ABW zeolite framework, focusing on the synergistic effect of co-adsorbed water molecules. Six distinct systems were modeled: empty Li-ABW zeolite, half and full filled Li-ABW with H 2 O or H 2 S molecules, and equally filled zeolite with H 2 S and H 2 O molecules. Detailed analysis of geometric, energetic, and electronic properties reveals that the presence of water significantly enhances H 2 S adsorption in Li-ABW. Increased bond lengths between H 2 S and the zeolite framework suggest possible dissociative adsorption, while weakened H 2 S-zeolite interaction compared to H 2 O-zeolite interaction indicates facile H 2 S desorption. Furthermore, charge transfer analysis and HOMO/LUMO plots highlight stronger interactions and a more balanced electron distribution in the co-adsorbed system. Interestingly, the presence of water minimizes structural deformations of the zeolite framework while facilitating the formation of additional hydrogen bonds, potentially further promoting H 2 S desorption through water extraction. These findings demonstrate that Li-ABW zeolite, particularly in conjunction with water molecules, exhibits remarkable potential for efficient and selective H 2 S adsorption, offering promising avenues for practical applications in gas sweetening and industrial gas purification. In order to realize this potential, further investigation into the effects of solvents and cation exchange is necessary, which are outlined for future research. [Display omitted] • The DFT calculations reveal the behavior of hydrogen sulfide (H₂S) adsorption within Li-ABW zeolite channels. • Four distinct systems investigated, varying H₂O/H₂S to understand adsorption influence. • Presence of a water molecule significantly enhances H₂S adsorption, exhibiting exothermic and stable interactions. • Two H₂S in Li-ABW zeolite cause structural/energetic changes, indicating endothermic adsorption. [ABSTRACT FROM AUTHOR]

Membranes are considered promising tools for gas sweetening due to their lower footprint (i.e., area and energy requirement, considering elimination of solvent/absorbent and its associated regeneration procedures), and ease of scale-up. Performing membrane gas separation is strongly dependent on membrane materials. With a 0.38-nm pore size, the SAPO-34 membrane surpasses the upper bond limit for CO2/CH4 separation. However, preparing defect-free and high-performance zeolite membranes is quite challenging. This paper reviews gas transport and separation mechanisms in SAPO-34 membranes, and it discusses prospective approaches for obtaining membranes with defect-free selective layers and hence high separation performance. Highlights, as well as the authors' perspectives on the future development of SAPO-34 membranes in the field of gas separation, are pointed out. [ABSTRACT FROM AUTHOR]

Introduction: In order that the amine regenerator can supply H2S to the sulfur recovery unit, it is necessary to increase the operating pressure of this tower. This process could cause operational problems, degradation or amine inventory loss, among other drawbacks. Objective: To analyze the influence of the amine regenerator operational parameters to supply H2S to the sulfur recovery unit. Materials and Methods: For the evaluation of the amine regenerator, the characteristics of the streams, products and technical specifications of the involved equipment are obtained. With these characteristics, the information flow diagram is prepared and then the simulation model is validated with respect to the design parameters of the regenerator. The CHEMCAD simulator is used, since it contains the amine thermodynamic package, necessary for the simulation of said regenerator. Results and Discussion: The pressure of the amine regenerator can vary in a range between 1.91E+005 - 2.26E+005 Pa, obtaining a composition of H2S in this stream between 24.36 - 23.90 kmol/h and in the final amine stream a composition between 144.898 - 144.899 kmol/h. The temperature for this described parameters does not exceed the value of 121.7 ° C, which eliminates the possibility of degradation of the amine and therefore losses. Conclusions: It has been shown theoretically that it is possible, in this pressure range, for the acid gas stream (H2S) to enter the raw material drum of the sulfur recovery unit. [ABSTRACT FROM AUTHOR]

In this study, raw natural gas data from Uch gas field located in Dera-Bugti of Balochistan, Pakistan is simulated for performance analysis over amine absorber unit in Aspen HYSYS V9.0. The primary amine, MDEA was selected to remove bulk CO2 and reduce H2S to ppm level, where secondary amines, MEA, DEA and Sulfolane were selected to observe CO2 levels in sweet gas. The primary amine in isolation and blend with secondary amine was simulated and analysed over absorber performance. The absorber performance is reported as CO2, H2S and water content in sweet gas, hydrocarbons in rich amine and its temperature. MDEA in isolation resulted in minimum 14.13 and 12.78 mol% CO2 in sweet gas and rich amine temperature of 81.11oC and 82.13oC with 24 and 30-Trays, respectively at 2500 m3/h of lean amine recirculation rate. Among the tested blends, MDEA/MEA, MDEA/Sulfolane showed no significant improvement on absorber performance compared to isolated MDEA. However, MDEA/DEA blends indicated that CO2 in sweet gas can be reduced to 12.07, 3.41, 1.85 mol% with rich amine temperature of 89.05, 111.72 and 124.80oC, respectively. The lowest CO2 detected of 1.85 mol% was achieved with 40 mol% MDEA and 15 mol% DEA blend at 2500 m3/h recirculation rate and rich amine temperature of 124.80oC. The results indicated that MDEA/DEA blend has the potential to attain CO2 of less than 2 mol%. The higher rich amine temperature raise concern that can be resolved by using heat stabilized salt. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three-component MMMs were prepared by loading PU and nano-clay into PES. • Prepared MMMs were used for separation of CO 2 /N 2 and CO 2 /CH 4 mixtures. • Impact of additives on morphology, crystallinity, and chemical structure of MMMs was studied. • Modified PES membranes exhibited superior performance for CO 2 /N 2 and CO 2 /CH 4 separation. • Membrane containing 20 wt.% of PU and 2 wt.% of nano-clay had the best separation performance. In recent years, many efforts have been made to develop new membrane materials for natural gas sweetening (CO 2 /CH 4) and post-combustion CO 2 capture from flue gas (CO 2 /N 2), especially in coal-fired and natural gas-fired power plants. This study focused on the effect of polyurethane and nano-clay on structure and CO 2 separating properties of polyethersulfone (PES) based three-component mixed matrix membranes (MMMs). The different weight fractions polyurethane (PU) (5−30 wt.%) together with clay nano-sheets (Cloisite® 15A) (0.5−10 wt.%) were blended to fabricate a novel PES-based ternary MMMs. The principal purpose was to investigate the effect of loading PU polymer and layered clay particles with 2D channels on the gas separation performance of the PES membranes. Pure gas permeability for N 2 , CH 4 , and CO 2 , and ideal gas separation for CO 2 /N 2 and CO 2 /CH 4 mixtures were examined through neat PES and modified PES membranes. By incorporating 20 wt.% of PU into PES, the permeability of CO 2 and selectivities of CO 2 /N 2 and CO 2 /CH 4 were improved by 4, 1.4, and 1.7 times higher than the neat PES membrane, while by loading 20 wt.% of PU and 2 wt.% of nano-clay, the CO 2 permeability, and CO 2 /N 2 , and CO 2 /CH 4 selectivities were improved by 7.8, 1.8, and 2.2 times higher than the neat membrane, respectively. In general, PU and clay nano-sheets together as a filler into the PES matrix exhibited a meaningful improvement in the gas permeation and separation properties of PES and can be admitted as a worthy membrane for CO 2 separation from the flue gas and natural gas. [ABSTRACT FROM AUTHOR]

CO2 removal is imperative in the sweetening of natural gas. In this work, a hybrid method combining membrane separation and chemical absorption is proposed and applied to test its performances in CH4 refinement and CO2 separation from natural gas. Specifically, the permeate stream from the membrane separation part was fed into the chemical absorption column. The retentate stream and the chemically scrubbed permeate stream were mixed to produce the final sweetened CH4. Parametric analysis indicates that the enriched CH4 volume fraction increases with the growth of feed pressure, but it decreases as the gas flow rate increases. The CO2 removal efficiency gets enhanced with the increment of feed pressure, gas temperature and monoethanolamine (MEA) concentration. Under an optimized condition with a feed pressure of 0.9 MPa, a gas flow rate of 40 L/min, a gas temperature of 45°C, a MEA concentration of 15%, and a MEA flow rate of 20 L/h, the high CH4 volume fraction of 96.8%, 100% CH4 recovery efficiency, and 80.4% CO2 removal efficiency can be simultaneously achieved using the hybrid method. Compared with the membrane separation method, the hybrid method has higher CH4 recovery efficiency and higher CH4 volume fraction, which can meet the requirements of carbon capture utilization and storage (CCUS). Compared with the chemical absorption, the hybrid method consumes less MEA since a part of CO2 can be separated by membrane separation. Therefore, the hybrid method is a promising technique for flexible CH4 refinement and CO2 separation in natural gas. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Diethanolamine (DEA) solutions are used in refineries to sweeten gas. DEA is responsible for absorbing H 2 S from sour gas. In an Amine Regeneration Unit (ARU), the rich amine with H 2 S is regenerated. A refining column in the Middle East started commercial production in 2020. Using Aspen HYSYS V.11, an amine regeneration unit in the refinery that supplies lean amine to the delayed cooker unit for gas sweetening was simulated, and an exergy study was performed on various equipment. Exergy is destroyed in an irreversible process, while energy is converted from one type to another. The sum of the physical and chemical exergy is the total exergy. The chemical exergy was calculated using a series of equations embedded in Excel, while the physical exergy was calculated using HYSYS. The DEA concentration used is 25 wt%. Each equipment's exergy destruction rates, destruction efficiency, and percentage share of destruction were determined. The regenerator had the highest destruction rate of 2144.11 kW and an 80.21 percent share of total destruction. With a value of 326.00 kW and a percentage share of 12.20 percent of total destruction, the air cooler has the second-highest exergy rate. Exergy has a 99.70 percent overall efficiency. Due to system losses, the DEA concentration fell from 25% to 20% of the design value. The regenerator had the highest destruction rate of 2616.74 kW followed by the air cooler with a value of 294.61 kW. In DEA 20%, an exergy analysis was carried out. Exergy research showed the same percentage share distribution for equipment at a concentration of 20 DEA wt. percent. To find related equipment relationships, the results of the unit's exergy analysis were compared to those of another ARU exergy study at the same refinery plant. The regenerators were found to have the highest exergy destruction of the two units with a percentage share of the overall destruction reaching 80% followed by the air coolers with values reaching 9%. [ABSTRACT FROM AUTHOR]