Feed Gas Concentration Research Articles

Modelling carbon capture from power plants with low energy and water consumption using a novel cryogenic technology

Global warming mitigation requires modern energy generation technology to integrate low-cost carbon capture techniques. Despite volumes of research on the latter, the significantly high unit energy (MWh) of capture and high water consumption, do not enable any current carbon capture techniques to be adopted at a scale. To address this problem, we theoretically explore a novel low-cost carbon capture technology (NLCCT). In this paper, a detailed thermodynamic analysis of the effects of the operating conditions and parameters of NLCCT, such as the initial feed gas concentration, compressor intercooler temperature, number of compressor stages, efficiencies of the compressors, and turbines, ambient temperatures on the energy consumption for CO2 capture (ECC) is carried out with a view to obtain costs much lower than current techniques. The study identifies the inlet feed concentration, turbine and compressor efficiencies, and compressor intercooler temperatures (heat transfer effectiveness) as the significant parameters. For a drop of 20 % efficiency, the ECC was found to increase by 40 %, and for an increase in inlet CO2 feed concentration from 4 % to 10 %, the ECC was found to decrease by 31 %. Considering the effect of intercooler temperatures, the ECC increases by 25 % when the intercooler temperature is raised by 6 K. The effect of ambient conditions was also analyzed and observed that for an increase of 27C in the ambient temperature, the ECC would rise by 15 %.

Intrinsic kinetics of steam methane reforming over a monolithic nickel catalyst in a fixed bed reactor system

The intrinsic kinetics of steam methane reforming were experimentally investigated using a monolithic nickel-based catalyst in a specially designed fixed bed system. All kinetic tests were performed under various operating conditions: steam to carbon ratio of 2 to 5, methane volumetric concentration in feed gas of 3 % to 9 %, temperature of 500 to 650 °C, and typical biogas compositions with N2 dilution (carbon dioxide 35.7–55.6 %, methane 44.4–64.3 %, with 86–91 % nitrogen dilution). A deconvolution process was applied during the rate calculation and the reaction orders with respect to different gases were determined, coupled with thermodynamic system analysis. The reaction mechanism was then proposed and a Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetic model was established, followed by kinetic parameter estimations for the model and a further model validation with experimental data. Based on the model, the intrinsic kinetic of SMR reaction using monolithic catalysts was described. The validity and feasibility of applying the faster approach for kinetic parameter estimation were demonstrated, and this work is the first demonstration of a complex reaction system. Also, the reaction mechanism appeared to show a suitably high correlation with alternative and more sustainable methane sources (i.e. biogas).

Coke oven gases processing by vacuum swing adsorption: Carbon capture and methane recovery

Coke oven gas (COG), a by-product gas from the steel industry with great potential for chemical utilization, contains multiple high-value gases including H2, CO2, and CH4. Our previous work has successfully achieved hydrogen production from COG with a purity greater than 99.99 %. For further separation of COG-to-hydrogen tail gas, a two-phase vacuum swing adsorption (VSA) strategy for CO2 capture and CH4 upgrading was carried out in this study. The accuracy of the 4-bed 8-step and 4-bed 7-step cycles established in the in-house mathematical model was verified through a series of multi-component breakthrough and VSA experiments for the two-stage CO2 capture and CH4 upgrading processes employing zeolite NaY and activated carbon RB3, respectively. To achieve more excellent separation performance, several novel VSA cycles were designed and developed in terms of each stage, and the Pareto fronts of purity and recovery of CO2 or CH4 for each cycle were obtained through a multi-objective optimization framework. Based on this, the separation performance and energy consumption of the optimal cycle for each stage were parametrically analyzed under various feed gas concentrations, vacuum pressures, and feed velocities. Moreover, the CO2 product with a purity of 95.58 % and a recovery of 90.11 % can be obtained ultimately by using a 4-bed 8-step cycle for the first stage and a 4-bed 7-step cycle for the second stage of the CO2 capture process under 0.1 bar vacuum pressure. The CH4 upgrading process using a 4-bed 7-step cycle at 0.1 bar vacuum pressure produced a product with 92.07 % purity and 98.81 % recovery. The specific energy consumption was 32.17 kJ/mol and 1.80 kJ/mol for CO2 capture and CH4 upgrading, respectively. Recovery of high-purity CO2 and CH4 at such medium vacuum pressure and low energy consumption through a two-phase VSA strategy from COG has great application potential.

Experimental study on the flux-controlled growth of CO2-SO2 hydrates: Implications for hydrate-based CO2 sequestration

Sulfur dioxide (SO2), an impurity in flue gas, could reduce capture costs if it could be co-sealed with carbon dioxide (CO2) as hydrates. This paper investigated the one-dimensional growth process and selectivity of diffusive flux-controlled CO2-SO2 hydrates using in situ Raman spectroscopy at different temperatures (278.15 and 283.15 K), pressures (5 and 10 MPa), and feed gas concentrations (4 % and 7 % SO2). It is found that, macroscopically, separation factors (S.F.) at the hydrate-aqueous solution interface reveal that the hydrate is more selective for CO2 (S.F. < 1), with SO2 more inclined to dissolve in water. Microscopically, the less abundant SO2 in the aqueous solution would be locally depleted, providing heterogeneous nucleation sites for the surrounding dissolved CO2, promoting CO2 hydrate formation. The increase in SO2 concentration would increase the hydrate growth rate and accelerate the CO2 sequestration process. The results provide valuable insights into the synchronized sequestration of CO2-SO2 by hydrates.

Impact of spacer on membrane gas separation performance

Mixing in gas separation membranes has received much less attention than in membrane liquid separation because gas molecules have much smaller viscosity, allowing them to diffuse easily through membranes without requiring significant flow mixing. However, due to advancements in membrane fabrication technologies aimed at improving material properties, concentration polarization (CP) might become an issue in gas separation due to enhanced membrane efficiency and permeability. Consequently, a 2D CFD analysis is conducted to evaluate the impact of spacer-induced mixing on membrane gas concentration polarization for typical CO2/CH4 gas separation. Results show that spacers generally enhance flux performance while reducing CP in the membrane channel when compared to the case without spacers. Furthermore, the effectiveness of spacer-flux-to-pressure-loss-ratio (SPFP) reaches a peak for a Reynolds number in the range of 5 <Reh< 200 because of the trade-off between flux and pressure drop. This mixing-induced flux enhancement is most effective under high CP conditions (less mixing) within the membrane channel. Similarly, flux enhancement due to spacers can be observed as membrane selectivity, pressure ratio and feed gas concentration increase due to enhanced CP.

Characteristics of hydrogen separation and methane steam reforming in a Pd-based membrane reactor of shell and tube design

This work investigates numerically the characteristics of the two process, hydrogen separation and steam methane reforming (SMR), in a palladium-based (Inconel-supported Pd–Ag film) membrane reactor (MR) of porous reformer (30% Ni/Al2O3) shell and multi-tube design. Still parameters like reactor design and temperature, feed gas concentration and pressure, and flow configuration need more investigation to figure out their impact on hydrogen production rate at lower energy cost and minimum possible volume. This work targets optimization of reactor performance for higher hydrogen yield and coming up with a scalable optimized reactor design for industrial applications. First, an optimization study is performed under non-reforming (separation-only) conditions to optimize the MR design and operating parameters for higher hydrogen production. Then, the study is extended to consider hydrogen separation under SMR conditions to come up with a MR design for hydrogen production at the industrial scale. Hydrogen permeation is limited to small zone near the membrane surface with no effect of feed pressure, inlet gas temperature, and feed hydrogen concentration on widening such zone that necessitates reducing the pitch distance between membrane tubes below 22 mm. The results showed reduced hydrogen permeation rate under SMR conditions compared to the separation-only cases.

Metrology of Ar-N2/O2 Mixture Atmospheric Pressure Pulsed DC Jet Plasma and its Application in Bio-Decontamination.

Atmospheric pressure plasma jets are gaining a lot of attention due to their widespread applications in the field of bio-decontamination, polymer modification, material processing, deposition of thin film, and nanoparticle fabrication. Herein, we are reporting the disinfection of Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli bacteria using plasma jet. In this regard, Ar-O2, Ar-N2, and Ar-O2-N2 mixture plasma is generated and characterized using optical and electrical characterization. Variation in plasma parameters like electron temperature, electron density, and reactive species production is monitored with discharge parameters such as applied voltage and feed gas concentration. Results show that the peak average power consumed in Ar-O2, Ar-N2, and Ar-O2-N2 mixture plasma is found to be 4.45, 2.93, and 4.35 W respectively, at 8 kV. Moreover, it is noted that by increasing applied voltage, the electron temperature, electron density, and reactive species production also increases. It is worth noting that electron temperature increases with increase in oxygen concentration in the mixture (, while it decreases with increase in nitrogen concentration in the mixture (Ar-N2). Similarly, a decreasing trend in electron temperature is noted for Ar-O2-N2 mixture plasma. On the other hand, a decreasing trend in electron density is noted for all the mixtures. Reduction in viable colonies of Pseudomonas aeruginosa, Staphylococcus Aureus, and Escherichia coli were confirmed by the serial dilution method. The inactivation efficiency of pulsed DC plasma generated, in the Ar-N2 mixture at 8 kV and 6 KHz, was evaluated against P. aeruginosa, S. aureus and E. coli bacteria by measuring the number of surviving cells versus plasma treatment time. Results showed that after 240 s of plasma treatment, the number of survival colonies of the mentioned bacteria was reduced to less than 30 CFU/mL.

Toward a Stackable CO2-to-CO Electrolyzer Cell Design─Impact of Media Flow Optimization

Aqueous CO2-to-CO electrolysis is a promising technology for closing the carbon cycle and defossilizing industrial processes. Considering the technological readiness, consensus has been achieved about using silver as a stable and selective electrocatalyst for the CO2-to-CO reduction reaction in aqueous electrolyte. On the other hand, challenges such as media flow management, component stability, and force distribution are still associated with improving the process performance and developing a stackable cell concept to meet industrially relevant levels. We therefore report on a promising stack concept with continuous flowcells operated with gas diffusion electrodes (GDEs). To enhance the CO2-to-CO conversion efficiency, dedicated media flow chambers were developed on two levels. In the gas chamber, which touches the GDE from the far side of the anode, the feed gas flow and distribution over the GDE were controlled by introducing various gas path architectures in a modular flowcell. In addition, an ionically conductive spacer was implemented in the catholyte chamber, which is adjacent to the opposite side of the GDE. The effect of these modifications on the cell voltage, selectivity, and overall conversion was investigated at 100 mA/cm2 with varying CO2 feed gas flow and concentration. Noteworthy, an optimized feed gas distribution generated an increase of the Faraday efficiency for CO under reduced CO2 supply. Furthermore, the implementation of the spacer enhanced the process stability by suppressing gas-bubble-induced noise in the cell voltage measurements. By functioning as support structures to the GDE, the combined modifications provided the cell with mechanical integrity and allowed an ionic and electric contact over the full active cell area, which is required for both stacking and upscaling of the cell. The corresponding performance was demonstrated by a two-cell short-stack.

High-purity CO2 recovery following two-stage temperature swing adsorption using an internally heated and cooled adsorber

The availability of relevant and efficient technologies to capture, store, and use carbon dioxide (CO2) is critical to reduce CO2 concentrations in the atmosphere and reach net-zero CO2 emissions. In this study, we captured CO2 by combining an adsorbent-packed heat exchanger with an internal heating and cooling process of thermal swing adsorption. A two-stage process was used to achieve CO2 purity greater than 90 % in the simulated flue gas because the single-stage process could only concentrate CO2 to ∼ 50 % purity. The results revealed that the volume of the second-stage adsorption heat exchanger is approximately-one-third of the first-stage adsorber because the CO2 concentration of the second-stage feed gas increases in the first stage, thereby leading to an increase in the adsorption capacity of the second stage. Maximum CO2 purity of 95 % was achieved using the rate of purge air flow and regeneration time in the second-stage regeneration process as operating parameters. The overall CO2 recovery ratio was ∼ 60 %. The results of the study indicate the need to enhance the recovery ratio for improved performance.

Optimization Analysis of Pretreatment Device Structural Parameters for Low-Concentration CBM Utilization

The unstable concentration of the difficulty in utilizing low-concentration CBM causes a large amount of CBM to be discharged into the atmosphere. In order to ensure the safe and stable operation of the CBM utilization device, the gas mixing unit is used to stabilize the concentration of feed gas. Generally, the resistance of the gas mixing unit is not higher than 500 Pa and the uniformity of gas is not less than 90%. In order to solve the problems of heavy resistance and low uniformity of the existing CBM mixing unit, a three-dimensional calculation model is established, and the structural parameters such as the number of spiral blades, blade length, and pitch in the gas mixing unit are adjusted and verified by experiments to achieve optimal performance. The dimensionless mathematical correlation between the resistance loss and the uniformity of gas is refined, and the maximum error between the resistance loss and the simulation results is controlled within 10%; it provides a theoretical basis for the uniformity and low resistance mixing of different gases in the gas industry. When the flow is 7000 Nm3/h, 50000 Nm3/h, and 160000 Nm3/h, respectively, the optimal structural parameters of the mixing zone are as follows: the number of blades is 3, 3, and 2, respectively, the pitch is 1000 mm, 2000 mm, and 2636 mm, respectively, and the length of blades is 500 mm, 1600 mm, and 1845 mm, respectively. The optimal structural parameters of the small pipe area are as follows: the mixing device with a flow of 50000 Nm3/h is not equipped with blades, the number of blades of the other two devices is 4, the pitch is 1400 mm, and the length of blades is 700 mm.

Study Details Management of Mercury for Production Facilities

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 31465, “Management of Mercury Offshore for Onshore Production Facilities,” by Mohamed Sopiee Saaibon, Zainab Kayat, and Fatimah A. Karim, Petronas. The paper has not been peer reviewed. Copyright 2022 Offshore Technology Conference. Reproduced by permission. The objective of the complete paper is to provide an approach to mitigating the adverse effects of mercury found in production fields. It includes an evaluation of treatment-facility requirements and suitable technologies for production fields and facilities. The evaluation covers assessment of pipeline integrity and managing unexpected increases in mercury content to ensure that mercury removal units (MRU) can treat gas within design specifications. Introduction Mercury is present as a contaminant in many oil and gas reservoirs; southeast Asia is a well-known for high concentrations of mercury. The presence of mercury poses a threat to the operator’s integrated upstream value chain. The primary concern is exposure of mercury to downstream aluminum heat exchangers for liquefied natural gas (LNG) production. The production lines and risers, although made of carbon steel, are exposed to integrity threats and, consequently, risk deferment of production. Initial Problem Concerns regarding mercury’s presence in hydrocarbon processing systems arose when substantial liquid mercury was detected at the operator’s downstream onshore LNG plant at levels three times beyond the design of its existing onshore MRU within the plant. Such high mercury concentration in feed gas was not expected because the wells had been operational for only 1 year. Immediate measures taken to handle these high quantities of mercury to protect the plant and its aluminum equipment included the following: - Reduction of feed-gas intake and production slowdown - Closing of wells with high mercury content - Mixing of that gas with low-mercury gas - Preparation for MRU adsorbent changeout No method exists to predict mercury production, and thus mitigation and equipment design—particularly that of an MRU across an integrated oil and gas production system—cannot be based on subsurface production data alone. A holistic approach to determine reservoir mercury concentrations from geology by on onsite sampling and mapping, from the wellhead to the production facility along the pipeline to the plant, was initiated.

An Electro-Reductive Removal of Gaseous Toluene By a Copper-Nickel Complex Mediator at Gas-to-Solid Interface

Electrochemical technique is one of the most promising methods for the removal of volatile organic compounds such as toluene. However, the conventional gas electrolysis method has mass transfer limitation, and the homogeneous catalysts are often irrecoverable after the reaction is completed, which leads to inefficient, less environmental-friendly, and uneconomical performance. This study proposes a gas-to-solid electrolysis system employing an electrode coated with heterogenous catalyst as the electron transfer mediator. A CuNi(CN)4 complex was prepared according to a published method and drop-coated on a commercial copper mesh electrode with 5% Nafion solution. The CuNi(CN)4 coated copper electrode was further covered by 10 M of NaOH solution by drop-coating to increase the pH, which in turn widens the potential window. The prepared CuNi(CN)4 electrode was characterized by XRD and SEM-EDS analyses. The XRD and SEM-EDS analyses evidenced the CuNi(CN)4 presence with structural and composition details. Characteristics of electrodes and mediators were also confirmed through various analysis methods. Additionally, an electrochemical confirmation of CuNi(CN)4 presence by its redox behavior was inferred by gas-phase cyclic voltammetry. After confirmation of mediator presence, electrode mounted in a Nafion membrane divided electrolytic cell at the cathodic half-cell for the gas phase reductive electrolysis. A PVA gel was inserted in-between the Nafion membrane and the cathode to serve as a solid electrolyte to facilitate the electron transfer process. The electrochemical reduction of gas-phase toluene was carried out using a continuous flow model and chronoamperometry method. Different experimental parameters such as feed gas flow rates and concentrations were investigated on toluene removal. GC-MS analyses were applied to measure toluene concentration and intermediate compounds identification. A possible reaction mechanism will be discussed in detail at the conference.AcknowledgmentThis research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(NRF-2021R1I1A1A01049901) and also from the Grants No. NRF-2020R1A6A1A03042742

Interfacially-confined polyetherimide tubular membranes for H2, CO2 and N2 separations

Capturing CO2 and H2 purification from gas mixtures such as CO2/N2 and H2/N2 are vital in addressing greenhouse gas emission abatement and global energy strategy. Here, we present a systematic investigation of tubular polyetherimide (PEI) membranes prepared by combining dip-coating and multilayer assembly techniques to target CO2 and H2 transports and CO2/N2 and H2/N2 selectivities. The effects of deposition cycle during dip-coating on H2, CO2 and N2 single gas permeations and binary gas separations were evaluated. The membranes prepared by three deposited layers produced gas permeances (10−12 mol m−2 s−1 Pa−1) of 310, 150 and 1 for H2, CO2 and N2 respectively, corresponding to CO2/N2 and H2/N2 permselectivities of 149 and 308. For binary gas mixture separation, an exclusive 100% CO2 and H2 permeate purity was observed irrespective of feed gas concentration. The PEI membrane exhibited a suppression of glass transition temperature and crystallinity compared to the bulk polymer indicating interfacial confinement phenomenon, which was further confirmed by X-ray diffraction and Raman spectroscopic analyses. Due to a subtle change of imide group conformation of the obtained membrane layer, it was inferred that an increase in the polymer amorphicity and interfacial confinement facilitated the exclusive H2 and CO2 transports without much affecting the N2 permeance.

N-Octyltrichlorosilane Modified SAPO-34/PDMS Mixed Matrix Membranes for Propane/Nitrogen Mixture Separation

In this study, zeolite molecular sieve SAPO-34/polydimethylsiloxane (PDMS) mixed matrix membranes (MMMs) were prepared to recover propane. n-Octyltrichlorosilane (OTCS) was introduced to improve compatibility between SAPO-34 and PDMS, and enhance the separation performance of the MMMs. Physicochemical properties of the MMMs were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and water contact angle (WCA). Results showed that, after modification, alkyl chains were successfully grafted onto SAPO-34 without changing its crystal structure, particles in the MMMs were evenly distributed in the base film, and the hydrophobicity of the MMMs was enhanced. Moreover, the effects of SAPO-34 filling content, operating pressure, and feed gas concentration on the separation performance was explored. This indicated that the modification with OTCS effectively enhanced the separation performance of SAPO-34/PDMS MMMs. When the filling content of modified SAPO-34 was 15%, the maximal separation factor of 22.1 was achieved, and the corresponding propane permeation rate was 101 GPU.

Experimental study on heat transfer caused by feed gas concentration fluctuation in low concentration CBM utilization unit

Experimental study on heat transfer caused by feed gas concentration fluctuation in low concentration CBM utilization unit

Enhanced Hydrate-Based Geological CO2 Capture and Sequestration as a Mitigation Strategy to Address Climate Change

Geological sequestration of CO2-rich gas as a CO2 capture and storage technique has a lower technical and cost barrier compared to industrial scale-up. In this study, we have proposed CO2 capture and storage via hydrate in geological formation within the hydrate stability zone as a novel technique to contribute to global warming mitigation strategies, including carbon capture, utilization, and storage (CCUS) and to prevent vast methane release into the atmosphere caused by hydrate melting. We have attempted to enhance total gas uptake and CO2 capture efficiency in hydrate in the presence of kinetic promoters while using diluted CO2 gas (CO2-N2 mixture). Experiments are performed using unfrozen sands within hydrate stability zone condition and in the presence of low dosage surfactant and amino acids. Hydrate formation parameters, including sub-cooling temperature, induction time, total gas uptake, and split fraction, are calculated during the single-step formation and dissociation process. The effect of sands with varying particle sizes (160–630 µm, 1400–5000 µm), low dosage promoter (500–3000 ppm) and CO2 concentration in feed gas (20–30 mol%) on formation kinetic parameters was investigated. Enhanced formation kinetics are observed in the presence of surfactant (1000–3000 ppm) and hydrophobic amino acids (3000 ppm) at 120 bar and 1 ℃ experimental conditions. We report induction time in the range of 7–170 min and CO2 split fraction (0.60–0.90) in hydrate for 120 bar initial injection pressure. CO2 split fraction can be enhanced by reducing sand particle size or increasing the CO2 mol% in incoming feed gas at given injection pressure. This study also reports that formation kinetics in a porous medium are influenced by hydrate morphology. Hydrate morphology influences gas and water migration within sediments and controls pore space or particle surface correlation with the formation kinetics within coarse sediments. This investigation demonstrates the potential application of bio-friendly amino acids as promoters to enhance CO2 capture and storage within hydrate. Sufficient contact time at gas-liquid interface and higher CO2 separation efficiency is recorded in the presence of amino acids. The findings of this study could be useful in exploring the promoter-driven pore habitat of CO2-rich hydrates in sediments to address climate change.

Separation of IGCC syngas by using ZIF-8/dimethylacetamide slurry with high CO2 sorption capacity and sorption speed but low sorption heat

An absorption-adsorption hybrid method for separating the integrated gasification combined cycle (IGCC) syngas using ZIF-8/dimethylacetamide (DMAC) slurry was proposed. The viscosity of ZIF-8/DMAC slurries and its sorption performance of pure CO2 were investigated and one optimized slurry with moderate viscosity and high sorption capacity was proposed. Parallel absorption experiments show that the apparent solubility of CO2 in the slurry was doubled compared with that in pure liquid DMAC or propylene carbonate; it even overcomes that in aqueous monoethanolamine solutions at middle to high pressure range. More importantly, the slurry exhibits higher CO2 capture speed compared with conventional absorbents, while its desorption heat is only ∼16 kJ/mol. The equilibrium separation results on H2/CO2 mixtures using ZIF-8/DMAC slurry show that the selectivity of CO2 over H2 ranged from 22 to 119; it increases with decreasing temperature or pressure, increasing initial gas to slurry ratio or CO2 concentration in feed gas. Only 4 theoretical equilibrium stages are required to achieve a sufficient separation of IGCC syngas. Regeneration test shows that the crystal structure of recovered ZIF-8 remains intact after 6 sorption-desorption cycles. This work provides an efficient method for the separation of IGCC syngas at pressure of 2–5 MPa.

Natural gas sweetening polymeric membrane: Established optimum operating condition at 70% of CO2 concentration feed gas stream

PETRONAS embarks on breakthrough technology for natural gas sweetening in high CO2 gas fields. Membrane technology is found to be one with high potential and a promising technology for bulk CO2 removal from natural gas. It can be suited to wide operating conditions to process varied natural gas composition, pressure and temperature. This paper focuses on the extensive development of PETRONAS in-house membrane and its evaluation for gas separation performance for high CO2 feed gas at different operating conditions; eg. feed gas flowrate, temperature, pressure, CO2 concentration in mixed gas system, and permeate pressure. For all the cases in this study, samples were tested at optimum gas flowrate of 1000 standard cm3/min (sccm) to obtain representative membrane performance. Feed gas pressure and CO2 concentration have shown significantly affect membrane permeation properties; whereas feed gas temperature and permeate pressure showed negligible impact. There is a trade-off between permeance and selectivity when CO2 concentration is increased from 40% to 70%; where the CO2 permeance increased by 12% which consequently reduces CO2/CH4 selectivity by 15%. In summary, the membrane developed in this study demonstrates high pressure durability up to 50 bar and temperature up to 55oC with satisfactory gas separation performance in the presence of high CO2 concentration in feed gas (up to 70% CO2). This work is breakthrough in establishing the operational boundary of PETRONAS Membrane for technology development and deployment in monetizing high CO2 gas field.

Hydrogen recovery from ammonia purge gas by a membrane separator: A simulation study

In this study, a two-dimensional mathematical model is proposed for modeling the hollow fiber membrane (HFM) separators for hydrogen (H2) recovery unit implemented in the Razi Petrochemical Company (Imam Khomeini Port, Iran) to capture hydrogen from ammonia (NH3) purge gas. In this regard, computational fluid dynamics is applied to solve the equations of momentum and mass transfer in the laminar flow conditions. Axial and radial diffusion for mass transfer inside the membrane fibers and axial diffusion within the shell side of separator were considered. The distributions of concentration, velocity, and mass transfer fluxes were achieved by the model. As the new insights, the effects of feed flow rate and feed gas concentration on mass transfer of H2 were investigated. Moreover, fluid velocity profile and H2 fluxes in the tube (fiber), membrane, and shell sides of the HFM separator were studied. The results of simulation were compared with the industrial data and showed that the present developed model has excellent agreement with the experimental data with a low mean deviation value of 3.5%.

An Analytical Solution Of 1-D Pseudo Homoneneous Model For Oxidation Reaction Using Homotopy Perturbation Method

In this paper, we propose an analytical solution of convective-diffusion equation that derived from an oxidation reaction in a chemical reactor. Here, concentration of feed gas as dependent variable. In this study, the reaction are assumed to be a one-dimensional pseudo homogeneous model and it is evaluated at a certain reaction rate. By rescaling process, the nonlinear term of the reaction rate can be approximated by a linear term, resulting a linear convective-diffusion equation with an initial condition and a set of boundary conditions. Here, we present an analytic solution of the initial condition and the boundary conditions using the homotopy perturbation method. The results show that at the end of the reactor, the solution is in agreement with numerical solution of the initial and boundary conditions.