Mixture Of CH4 Research Articles

Study on the Fuel Flexibility of a Microgas Turbine Combustor Burning Different Mixtures of H2, CH4, and CO2

Abstract The aim of this work is to analyze the behavior of the fuel flexible Ansaldo ARI100 T2 microgas turbine (MGT) combustor operated with mixtures having different H2, CH4, and CO2 concentrations. This combustor is going to be installed on an in-house modified Turbec T100 P MGT, which is originally equipped with a methane fired combustor. In a previous study, the combustor was simulated with a H2 enriched syngas, whose Wobbe index was within the limits imposed by the syngas supply system of an Ansaldo test bench. In this study, this constraint has been removed to gain a deeper understanding on how the fuel mixture properties (composition, heating value, and laminar flame speed) affect combustor performance. To this end, a series of Reynolds-averaged Navier–Stokes (RANS) computational fluid dynamics (CFD) simulations have been carried out on the full-scale 3D geometry of the combustion chamber, at full and partial load (50%), evaluating for each case combustion efficiency as well as NOx and CO emissions.

Structural and mechanism study on enhanced thermal stability of hydrogenated diamond-like carbon films doped with Si/O

a-C:H and a-C:H:Si:O films with two different Si/O co-doping contents had been deposited using a PECVD system by the mixture of C2H2 and HMDSO gas. The structure evolution of as-deposited and annealed films had been characterized by the Raman spectroscopy, XPS and FTIR. A progressive increase of sp2 carbon sites and a reduction of sp3 with the increase of the annealing temperature were expected. However, the Si/O co-doping was found to be able to reduce the graphitization degree of the annealed films. After annealing at 400 °C, the decrease rate of sp3 fraction of a-C:H film was 14.2%, while the a-C:H:Si:O (0.93 at.% Si) film was 8.16% and the a-C:H:Si:O (3.62 at.% Si) film was 6.8%. To understand the mechanism on the improved thermal stability by Si/O co-doping, the structure and residual stress of the a-C:H and a-C:H:Si:O films were analyzed. The results revealed that silicon atoms were incorporated into the carbon network by substituting carbon atoms of the films, which had also been characterized contributed to produce the CSi sp3 bonds stabilized by the oxygen. Residual stress characterization also demonstrated that, the residual stress of the a-C:H:Si:O films was greatly reduced compared with that of the a-C:H films. Therefore, the fraction of the highly strained CC sp3 bonds, which were more likely to break at elevated temperature, was reduced in the a-C:H:Si:O films. This kind of structure evolution endowed the a-C:H:Si:O films higher hardness and adhesion at high temperature.

A Chemically Stable Hofmann-Type Metal-Organic Framework with Sandwich-Like Binding Sites for Benchmark Acetylene Capture.

The realization of porous materials for highly selective separation of acetylene (C2 H2 ) from various other gases (e.g., carbon dioxide and ethylene) by adsorption is of prime importance but challenging in the petrochemical industry. Herein, a chemically stable Hofmann-type metal-organic framework (MOF), Co(pyz)[Ni(CN)4 ] (termed as ZJU-74a), that features sandwich-like binding sites for benchmark C2 H2 capture and separation is reported. Gas sorption isotherms reveal that ZJU-74a exhibits by far the record C2 H2 capture capacity (49 cm3 g-1 at 0.01 bar and 296 K) and thus ultrahigh selectivity for C2 H2 /CO2 (36.5), C2 H2 /C2 H4 (24.2), and C2 H2 /CH4 (1312.9) separation at ambient conditions, respectively, of which the C2 H2 /CO2 selectivity is the highest among all the robust MOFs reported so far. Theoretical calculations indicate that the oppositely adjacent nickel(II) centers together with cyanide groups from different layers in ZJU-74a can construct a sandwich-type adsorption site to offer dually strong and cooperative interactions for the C2 H2 molecule, thus leading to its ultrahigh C2 H2 capture capacity and selectivities. The exceptional separation performance of ZJU-74a is confirmed by both simulated and experimental breakthrough curves for 50/50 (v/v) C2 H2 /CO2 , 1/99 C2 H2 /C2 H4 , and 50/50 C2 H2 /CH4 mixtures under ambient conditions.

Methane Dry Reforming over Ni/Al2O3 Catalyst in Spark Plasma Reactor: Linking Computational Fluid Dynamics (CFD) with Reaction Kinetic Modelling

Efficient processes are needed for the valorisation of major greenhouse gases, methane and carbon dioxide, and electrification and energy storage are highly desired as well. Plasma based dry reforming provides the answer in all areas, as fast switch -on and -off times could use excess grid electricity to produce valuable products and decrease the carbon footprint. The reaction was studied in a non-equilibrium atmospheric pressure spark discharge reactor, which achieves higher yields than DBD reactors. CH4 and CO2 feed mixture at different ratios was converted to H2 and CO with high selectivity, achieving conversions of 85% for CH4 and 75% for CO2. The syngas production energy cost was 315 kJ/mol, indicating 20% of input energy transferred to chemical energy. CO2 plasma regeneration and cyclic reaction operation was proposed to tackle the coking problem. With the intent of improving the yield, gaseous plasma was coupled with a solid Ni/Al2O3 heterogeneous catalyst, wash-coated on porous alumina foam material. The effects of specific energy input, external heating temperature and gas flow rate were also screened. In addition, a CFD and chemical kinetics model was developed in order to further investigate the system, which achieved good agreement with the experiments using relatively simple chemistry.

Adsorption Characteristics of CO2/CH4/N2 Ternary Mixtures on Anthracite from 293.15 to 353.15 K and Pressures Up to 7 MPa.

We present the adsorption data of CO2, CH4, and N2 ternary mixtures on anthracite from 293.15 to 353.15 K and pressures up to 7 MPa obtained via a volumetric method. The experimental data are given at different conditions, and simple analysis is made. The results show that the excess adsorption capacity of the CO2/CH4/N2 mixture and its component gases decreases linearly with the increase of temperature for constant composition. The total adsorption capacity is between pure CO2 and pure N2 in the entire pressure range. The effect of total pressure on total adsorption capacity is mainly influenced by the CO2 mole fraction in the feed gas. However, the adsorption capacities of CH4 and N2 decrease, and CO2 presents a maximum with the decrease in total pressure. For the feed gases of 10% CH4 and 16% CO2, the total adsorption capacity increases when the ratio of CO2 and CH4 increases, respectively, and the increasing magnitudes for 10% CH4 are larger than that of 16% CO2. The obtained experimental data are in agreement with the extended three-parameter Ono–Kondo model.

Biogas combustion with various oxidizers in a nanosecond DBD microplasma burner

This study concerns the effect of non-thermal plasma discharges on simulated biogas (mixture of CH4 with 80–20 vol% CO2) combustion at atmospheric pressure in synthetic air or synthetic air enriched by oxygen. The plasma-assisted, premixed combustion was performed in a porous-plate burner with dielectric barrier discharge microplasmas driven by nanosecond high-voltage pulses at 3 kHz and 10 kHz repetition rates in the burner holes. The characteristics of the plasma-assisted flames and the role of reactive oxygen species in the plasma-assisted combustion process supplying various oxidizers were determined using a spatial flame chemiluminescence scanning technique acquiring OH*, C2* and CH* emission intensities. From the obtained results, the pathways of combustion enhancement by the plasma were established.During plasma-assisted combustion, the biogas flame stability has improved. The highest plasma impact on the flame stability was observed for the biogas mixture (CH4-60%/CO2-40%). The flame lift-off for a stoichiometric mixture was reduced by 54% with the discharge at 10 kHz repetition rate, but a decrease of fuel–air ratio φ resulted in reduced effect of plasma and the lift-off was reduced only by 38–10% with 10 kHz discharge and by 22–7% with 3 kHz discharge. The experiments with oxygen-enriched synthetic air showed that the oxygen addition increases the flammability limit of biogas mixtures (CH4 with 50–20 vol% in CO2), and allowed to burn mixtures which were not able to combust under normal conditions. However, the plasma-assisted combustion with oxygen enrichment showed a lower effect on the combustion enhancement than without. During experiments of plasma-assisted combustion, the plasma impact on NOX emissions was also determined, showing that NOX concentrations increased with increasing plasma power.

A constitutive model for predicting the solubility of gases in water at high temperature and pressure

In the drilling and development of gas fields, gas exhibits good solubility in drilling fluids and in the formation water under high temperatures and pressures. Therefore, the prediction of the amount of dissolved gas in water plays a vital role in the development of natural gas. In this work, the principle of equal fugacity in a gas-liquid equilibrium, a non-iterative gas solubility prediction model was established. The gas-phase fugacity coefficient was calculated by the Peng-Robinson equation of state combined with the non-random mixing rule, and the liquid phase was calculated by Henry's law. The model can predict the solubility of CO2, CH4 and C2H6 in pure water at temperatures of 273–448 K and pressures of 0–100 MPa, with an error of less than 5.5%; however, the calculation accuracy for H2S was low. It is found that the effect of moisture in the gas phase of gas-liquid equilibrium cannot be ignored. Compared with the existing mixed gas solubility experimental data, this model could accurately calculate the solubility of non-polar mixed gases, such as CO2 + CH4, and CH4 + C2H6 mixture. For the mixtures containing a polar gas, the lower the polar gas content, the smaller was the prediction error of the model for the non-polar gas in the mixture. On the contrary, the higher the content of polar gas, the larger was the deviation in the prediction of non-polar gas in the mixture, but lower was the deviation in the prediction of polar gas. Finally, the ability of Krichevsky-Kasarnovsky equation to predict the solubility of pure gas was evaluated.

Effect of film thickness and methane fraction on explosion characteristics of biogas/air mixture in a duct

In order to evaluate the explosion characteristics of biogas (i.e., the mixture of CH4 and CO2), experiments were conducted in a duct with a length-to-width ratio of 10. The ignition was activated at the closed end while the opposite end was sealed by a PVC film of varying thickness. The effect of PVC film thickness and methane fraction in biogas was studied. The results show that there were three possible pressure peaks (Pb,Pmfa, Pext), due to the film failure, the attainment of maximum flame area and the external explosion, respectively. The pressure profile pattern was dependent on the combination of film thickness and methane fraction. Two pressure peaks Pb and Pmfa were observed for the PVC film thickness δ ≤ 0.033 mm. However, the pressure peak Pmfa was absent for the film thickness δ ≥ 0.055 mm because the PVC film did not rupture in these cases when the flame had touched the sidewall. In other words, the maximum flame area was achieved prior to the moment of venting. It signifies that in the absence of explosion venting, the flame quenching due to the sidewalls alone was insufficient to induce an individual pressure peak Pmfa. The third pressure peak Pext was low for the biogas explosion in the current configuration. The film thickness exerted a greater impact on bursting pressure Pb than did the methane fraction, at least for the range of film thicknesses and methane concentrations considered. Additionally, the individual effect of the film thickness or the methane fraction was less influenced by each other. The existing theories were accurate to predict the characteristic times of the flame propagation for δ = 0.011 mm but not for δ ≥ 0.033 mm. The PVC film thickness affected the explosion overpressure more, whereas the CH4 fraction in biogas affected the flame front velocity more remarkably.

Chemiluminescence-based characterization of tail biogas combustion stability under syngas and oxygen-enriched conditions

After the biogas is upgraded to CH4, a waste stream (tail biogas) is obtained, which contains methane in the order of few to tens vol.%. However, the composition of tail biogases can be unstable, therefore, safety should be maintained during the onsite combustion processes. Accordingly, a process control system with various sensors needs to be introduced. This study aims to analyze the experimental limits of flame stability using the chemiluminescence technique during the premixed combustion of low calorific tail biogas (mixture of CH4 with 15–30 vol% concentration in CO2) by adding oxygen or syngas. For the experimental investigation, a flat flame burner mounted in an enclosed combustion chamber was used. The stability of the flame was analyzed via the lift-off height by capturing the flame chemiluminescence from the excited OH* (282.9 nm), CH* (387.1 nm), and C2* (514.0 nm) radicals.This study reveals that the chemiluminescence spatial intensity of species such as OH*, CH*, and C2* is enhanced with an increase in the addition of syngas and oxygen. The peak position of the emission intensities in the flame shifts depending on the composition of gases, showing the existence of unstable flame that can reach its blow-off limit. When syngas is added, an excess of air leads to an increase in flame lifting; however, an O2 surplus results in more stable flame with minimized lifting. Moreover, it was determined that the lifting height of the flame is higher when syngas is added as compared to O2 enrichment. Finally, the flue gas emissions, such as CO and NOx, were examined and the most influential formation parameter was determined.

Systematic Regulation of C2H2/CO2 Separation by 3p-Block Open Metal Sites in a Robust Metal-Organic Framework Platform.

The separation of a mixture of C2H2 and CO2 is a great challenge due to their similar molecular sizes and shapes. Al-based metal-organic frameworks (Al-MOFs) have great promise for gas separation applications due to their light weight, high stability, and low cost. However, the cultivation of suitable Al-MOF single crystals is extremely difficult and has limited their explorations up to now. Since In, Ga, and Al are all 3p-block metal elements, a systematic application of the periodic law to investigate 3p-MOFs will undoubtedly help in the understanding and development of worthy Al-MOF materials. Herein, we report the design of a robust 3p metal-organic framework platform (SNNU-150) and the systematic regulation of C2H2/CO2 separation by open 3p-block metal sites. X-ray single-crystal diffraction analysis reveals that SNNU-150 is a 3,6-connected 3D framework consisting of [M3O(COO)6] trinuclear secondary building units (SBUs) and tritopic nitrilotribenzoate (NTB) linkers. Small {[M3O(COO)6]4(NTB)6} tetrahedral cages and extra-large {[M3O(COO)6]10(NTB)14} polyhedral cages connect with each other to generate a hierarchically porous architecture. These 3p-MOFs present very high water, thermal, and chemical stability, especially for SNNU-150-Al, which can maintain its framework at 85 °C in water for 24 h and in a room-temperature environment for more than 30 days. IAST calculations, breakthrough experiments, and GCMC simulations all show that SNNU-150 MOFs have top-level C2H2/CO2 separation performance and follow the order Al-MOF > Ga-MOF > In-MOF.

Phase-Resolved Measurement of Atmospheric-Pressure Radio-Frequency Pulsed Discharges in Ar/CH4/CO2 Mixture

In order to comprehensively investigate the discharge characteristics of an atmospheric-pressure radio-frequency (RF) pulsed discharge in Ar/CH4/CO2, a phase-resolved measurement is given in this paper. Firstly, the discharge characteristics of RF plasma in a gas mixture of Ar, CO2 and CH4 are investigated under different parameters. It is found peak power is more efficient than duty cycle in increasing the discharge area. Besides, a phase-resolved morphology of RF plasma is given. The discharge in the positive cycle is longer in length and stronger in emission intensity than in the negative cycle. Secondly, different activation paths of species have been obtained by using phase-resolved optical emission spectroscopy. Ar species is mainly activated by electron collision effect, while CH and C2 are mainly activated by Ar metastable species. Finally, detailed electron kinetics is analyzed. The results show that most energy is transferred to the vibrational excitation compared to elastic activation, electronic excitation, and ionization under different ratios of CO2 and CH4 to Ar. Besides, under a higher ratio of CH4 and CO2 to Ar, the generating rate of species and power loss rate are higher. It proves that higher fraction of CO2 and CH4 is better for the conversion rate and energy efficiency under RF discharge in theory, which guides the reforming of CH4 and CO2 in RF discharge.

Polyethersulfone based MMMs with 2D materials and ionic liquid for CO2, N2 and CH4 separation

Increasing concerns on global warming and climate change have led to numerous attempts on developing new membrane materials to reduce excessive CO2 emission into the atmosphere. In the present work, we focused on the separation of CO2 from gas mixtures through two-dimensional (2D) materials based mixed matrix membranes (MMMs). The ionic liquid (IL) 1-Ethyl-3methylimidazolium bis (trifluoromethylsulfonyl) imide together with different weight fractions (0.5–1.5 wt %) 2D materials, such as molybdenum disulfide (MoS2) and hexagonal boron nitride (h-BN), were homogenously blended to prepare polyether sulfone (PES) MMMs. The main aim was to investigate the effect of the addition of 2D materials on the gas separation/permeation properties of the PES membranes. Pure gas permeation for N2, CO2, and CH4 and binary gas mixtures separation for CO2/N2 and CO2/CH4 were investigated through pure PES and modified PES membranes. The prepared membranes were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and water contact angle tests. The gas permeabilities were found to be improved by average 15–20 times higher compared to pure PES. The αCO2/CH4 and αCO2/N2 were improved up to 124% and 18% using PES/h-BN (1 wt %)/IL and PES/MoS2 (1.5 wt %)/IL combination, respectively. In overall, 2D materials and IL together as a filler into PES matrix revealed a significant improvement in the gas separation/permeation properties of PES and can be considered as a competent membrane for CO2/CH4 and CO2/N2 separation.

Gelless Secondary Growth of Zeolitic Aluminophosphate Membranes on Porous Supports with High Performance in CO2 /CH4 Separation.

Zeolitic aluminophosphate, a three-dimensional microporous material, with an average pore size of 0.38 nm is good candidate for molecular sieve application in CO2 gas separation. The separation of CO2 /CH4 gas mixtures for precombustion processes is desirable from the standpoint of both environmental concerns and energy efficiency. This study concerns an environmentally friendly method to synthesize zeolitic aluminophosphate thin films on various configurations and low-cost kaolin porous substrates with high performance in the separation of CO2 /CH4 mixtures. The membranes are prepared by a gelless seed growth method that uses lower amounts of chemicals, forms no liquid gel, chemical waste, or byproducts and generates no washing water. The obtained membranes show very high selectivity for CO2 with a CO2 /CH4 separation factor above 1000 in the separation of CO2 /CH4 gas mixtures.

Using transient breakthrough experiments for screening of adsorbents for separation of C2H4/CO2 mixtures

The recovery of C2H4 from gaseous reactor effluents from processes such as oxidative coupling of methane (OCM), and biomass gasification (at relatively low temperatures (770–880 °C) is becoming of increasing industrial and economic importance. The reactor effluents are N2/H2/CO/CO2/CH4/C2H6/C2H4 mixtures, typically containing less than 15% C2H4. For recovery of C2H4, pressure swing adsorption (PSA) technology using a selective adsorbent offers an energy-efficient alternative to the more conventional separation schemes such as amine absorption and cryogenic distillation The major objective of this investigation is to screen commercially available cation exchanged zeolites (13X, CaX, NaY, 5A, 4A) and activated carbon (AC) to determine the most suitable adsorbent. For all these materials, the adsorption strengths of CO2, and C2H4 are significantly higher than that of other gaseous constituents; consequently, the C2H4/CO2 separation selectivity is the key to the efficacy of any adsorbent. The variety of adsorbents were screened using transient breakthrough experiments with feed mixtures using different C2H4/CO2 ratios. On the basis of the breakthroughs, the adsorbents could be distinguished in three different categories: (i) 13X and 4A are selective to CO2, (ii) CaX, NaY, and 5A are virtually non-selective, and (iii) AC is selective to C2H4 over the entire range of feed compositions and is therefore the adsorbent of choice.The experimental breakthrough results are also compared with simulations using published unary isotherm data, along with the Ideal Adsorbed Solution Theory (IAST) for determination of mixture adsorption equilibrium. This comparison demonstrates that screening adsorbents solely on the basis of IAST calculations is likely to be misleading. This article underscores the need for performing transient breakthrough experiments with realistic feed gas mixtures for process modelling and development purposes.

A MOF Glass Membrane for Gas Separation.

Metal-organic framework (MOF) glasses are promising candidates for membrane fabrication due to their significant porosity, the ease of processing, and most notably, the potential to eliminate the grain boundary that is unavoidable for polycrystalline MOF membranes. Herein, we developed a ZIF-62 MOF glass membrane and exploited its intrinsic gas-separation properties. The MOF glass membrane was fabricated by melt-quenching treatment of an in situ solvothermally synthesized polycrystalline ZIF-62 MOF membrane on a porous ceramic alumina support. The molten ZIF-62 phase penetrated into the nanopores of the support and eliminated the formation of intercrystalline defects in the resultant glass membrane. The molecular sieving ability of the MOF membrane is remarkably enhanced via vitrification. The separation factors of the MOF glass membrane for H2 /CH4 , CO2 /N2 and CO2 /CH4 mixtures are 50.7, 34.5, and 36.6, respectively, far exceeding the Robeson upper bounds.

Experimental Investigation of Flame Characteristics of H2/CO/CH4/CO2 Synthetic Gas Mixtures

ABSTRACT Chemical composition of synthetic gas and concentration of its components depend on gasification process and feedstock. Synthetic gas mainly consists of hydrogen (H2) and carbon monoxide (CO), and may contain trace amounts of carbon dioxide (CO2) and methane (CH4). In this study, combustion and emission characteristics of H2/CO/CH4/CO2 blending syngas mixtures with high H2/CO ratio were experimentally investigated in a swirl-stabilized premixed combustor. Furthermore, stable operating ranges (flashback and blowout equivalence ratios) of such mixtures and flame response of 67.5%H2-22.5%CO-5%CO2-5%CH4 mixture to acoustic forcing were also detected. During the experiments, CH4 amount in tested gas mixtures varied between 5% and 20% by volume (at intervals of 5%), and H2/CO ratio and CO2 concentration were kept constant at the values of 3 and 5%, respectively. As a consequence, mixtures of 67.5%H2-22.5%CO-5%CO2-5%CH4, 63.75%H2-21.25%CO-5%CO2-10%CH4, 60%H2-20%CO-5%CO2-15%CH4 and 56.25%H2-18.75%CO-05%CO2-20%CH4 were derived and tested under the same boundary and physical conditions. All experiments were conducted at 0.4 equivalence ratio (Φ) and 0.2 geometric swirl number (SN). Preliminarily, stable operating ranges of respective gas mixtures were determined to find an equivalence ratio at which all gas mixtures could be tested without causing any flame instability and then, CH4 addition effects on combustion and emission characteristics of such mixtures were evaluated via utilizing axial and radial temperature, CO and O2 profiles. Lastly, flame behavior of 67.5%H2-22.5%CO-5%CO2-5%CH4 mixture was evaluated under externally modified acoustic conditions. Acoustic field in the combustor was mechanically altered by using side-mounted loudspeakers in the frequency range of 30–200 Hz. To identify flame instabilities and to evaluate the degree of coupling between heat release and pressure oscillations, pressure sensors and photodiodes installed on combustion chamber and burner were utilized. Results of this study showed that CH4 addition to synthetic gas mixtures improves rich flammability limits, and increases flame temperature, flame height and emissions. Under externally modified acoustic conditions, flame behavior slightly alters (flashback and blowout does not occur). Additionally, pollutant emissions improve in an environment-friendly manner under such conditions.

The growth mechanism of Ge1−x-Cx:H films deposited by PECVD method

In the current study, the Ge1−x-Cx:H films were deposited on silicon and glass substrates by a plasma-enhanced chemical vapor deposition (PECVD) process with a gas mixture of GeH4 and CH4 as the precursors. For characterizing the films, field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), Rutherford backscattering spectrometry, elastic recoil detection analysis, and adhesion test were used. Based on the results, the growth mechanism of Ge1−x-Cx:H films by PECVD process was suggested as three separate steps including 1) the removal of surface H and the formation of dangling bonds, 2) insertion of germanium and methane radicals into the dangling bonds and 3) removal of inter-atomic H and the formation of GeGe, CC and GeC transverse bonds, respectively. If in the growth environment the radicals XH3 (X = Ge, C) be the dominant radicals, a two-dimensional growth occurs. On the other hand, the presence of a variety of radical species (XH3, XH2, XH) results in a preferred three-dimensional growth. With increasing the CH4: GeH4 flow rate ratio, the surface homogenization mechanism by H ions becomes more prevalent and consequently, the three-dimensional growth tends to the two-dimensional growth.

Decomposition of CO2 in a solar-gliding arc plasma reactor: Effects of water, nitrogen, methane, and process optimization

The decomposition of carbon dioxide (CO2) is a primary step towards its utilization in chemical synthesis processes that can help mitigate atmospheric CO2 emissions and fulfill the need for fuels and chemicals. The synergistic utilization of solar and electrical energy is investigated in a solar - gliding arc (glidarc) plasma system for the decomposition of CO2. The approach exploits the highly reactive species and radicals present in gliding-arc plasmas (a form of nonequilibrium electrical discharge) and the absorption of solar energy by the plasma towards enhancing reaction kinetics involved in gas-phase atmospheric pressure CO2 decomposition. Solar-glidarc plasma processing is investigated using undiluted CO2 and mixtures of CO2 with water vapor (CO2 saturated with water vapor), nitrogen, and methane. A two-phase Design Of Experiments (DOE) approach is followed to guide the investigation and analyze experimental results: phase 1 to identify the significance of the main parameters of the solar-glidarc reactor operation, and phase 2 to evaluate the optimal operating conditions towards maximizing CO2 decomposition. The results reveal that the CO2:CH4 (7:1) mixture yielded the maximum CO2 conversion of 49%, followed by 44% by the CO2-N2 (1:7) gas mixture. In contrast, the undiluted CO2 and CO2-H2O experiments show maximum CO2 conversions of 5% and 3%, respectively, and energy efficiencies of 15% and 12%, respectively. The optimal performance of the solar-glidarc reactor is attained with the CO2-N2 gas mixture, reaching a maximum energy efficiency of 70% and CO2 conversion of 44%.

Improved CO2 separation performance and interfacial affinity of mixed matrix membrane by incorporating UiO-66-PEI@[bmim][Tf2N] particles

This study demonstrated a new method for simultaneously improving the interfacial morphology and gas separation properties of mixed matrix membrane by designing a new type of nanocomposite filler (UiO-66-PEI@[bmim][Tf2N]). Nano-sized UiO-66 particle was post-synthetically modified with branched polyethyleneimine (PEI) and then was decorated with ionic liquid. The abundant amino groups in UiO-66-PEI improve the gas separation properties of the MMM due to the affinity between PEI and CO2. The ionic liquid acts as a lubricant agent, which is coated on the crystal surface improves the interface morphology of the MMM. Compared to pristine 6FO and MOF/6FO membrane, MOF@IL/6FO membrane has higher gas separation performance. Characterization and gas separation results indicated the UiO-66-PEI@ILs particles were homogeneous dispersed in 6FDA-ODA and promoted CO2 transport by reversible reaction with amine groups. Consequently, the membrane sample containing 15 wt% loading of the UiO-66-PEI@[bmim][Tf2N] filler displayed an optimum CO2/CH4 selectivity of 59.99 for CO2 and CH4 mixture gas.

The Comparative Study of Separation Process of CO2 and CH4 Mixture through Membrane and Adsorption Processes: A Short Review

The Comparative Study of Separation Process of CO2 and CH4 Mixture through Membrane and Adsorption Processes: A Short Review