Inlet Gas Concentration Research Articles

An experimental study on the effect of interstage inlet gas on separation performance of two-stage series cyclone separators

Cyclone separators generally operate in multi-stage series to improve gas-solid separation efficiency under high concentration condition. The two-stage series cyclone separators in Fluid Catalytic Cracking unit further require the interstage inlet gas. This paper experimentally studied the effect of the interstage inlet gas on separation performance of two-stage series cyclone separators. A ϕ130mm interstage inlet pipe was installed at the interstage connecting tube between industrial-sized two-stage series ϕ1000mm cyclone separators in the experimental setup. Experiments were conducted at inlet velocities of Vin = 10–20 m/s and concentration of Cin = 10 g/m3, with interstage inlet gas ratios of U = 0–20%. Silica powder with a median diameter of 10.1 μm was used. Results indicate that interstage inlet gas decreases separation efficiency and increases particle run-off loss due to the change of the optimized operation parameters, specifically inlet gas rate and inlet concentration. A prediction model was proposed to provide guidance for potential industrial applications.

Biodegradation enhancement of high concentrations formaldehyde waste gas and verification of the metabolic mechanism

The enhanced effects of formaldehyde biodegradation in a biofilm packing tower are investigated in this study. Three experimental groups were established: a blank control group, a biochar addition group, and a lanthanum addition group. The inlet gas flow rate, the inlet gas concentration, and the structural succession characteristics of the microbial community in the tower were investigated by regular sampling. The intracellular metabolites and key enzymes of the dominant functional bacteria, Pseudomonas P1 and Methylobacterium Q1, in the tower were analyzed. The results indicated that with the biochar addition, the formaldehyde purification efficiency increased significantly from 91.67–94.67 % to 94.12 96.85 %, and the bio-elimination capacity increased with an increase in the inlet gas flow rate from 2.314 to 13.988 mg L−1h−1 to 2.697–15.051 mg L−1h−1. With the addition of lanthanum, the purification efficiency increased significantly from 90.80–93.98 % to 94.36–96.78 %, and the bio-elimination capacity increased with an increase in the inlet gas concentration from 1.099–11.284 mg L−1h−1 to 1.266–11.961 mg L−1h−1. The microbial community structure in the tower changed with system operation, and the formaldehyde degrading functional bacteria formed the dominant bacteria. It was verified that P1 and Q1 metabolized high concentrations of formaldehyde by the serine cycle and the ribulose monophosphate (RuMP) cycle.

Ozonation using a stainless-steel membrane contactor: Gas-liquid mass transfer and pharmaceuticals removal from secondary-treated municipal wastewater

A tubular porous stainless steel membrane contactor was characterized in terms of ozone-water mass transport, as well as its application in removing 23 pharmaceuticals (PhACs) detected in the secondary-treated municipal wastewater, under continuous mode operation. The volumetric mass transfer coefficient (KLa) was evaluated based on liquid flow rate, gas flow rate, and ozone gas concentration. The KLa values were substantially improved with an increment in liquid flow rate (1.6 times from 30 to 70 dm3 h−1) and gas flow rate (3.6 times from 0.30 to 0.85 Ndm3 min−1) due to the improved mixing in the gas-liquid interface. For the lowest liquid flow rate (30 dm3 h−1), the water phase boundary layer (82%) exhibited the major ozone transfer resistance, but it became almost comparable with membrane resistance for the highest liquid flow rate (70 dm3 h−1). Additionally, the influence of the specific ozone dose (0.39, 0.53, and 0.69 g O3 g DOC−1) and ozone inlet gas concentration (CO3,g,in = 27, 80, and 134 g Nm−3) were investigated in the elimination of 23 PhACs found in secondary-treated municipal wastewater. An ozone dose of 0.69 g O3 g DOC−1 and residence time of 60 s resulted in the removal of 12 out of the 23 compounds over 80%, while 17 compounds were abated above 60%. The elimination of PhACs was strongly correlated with kinetic reaction constants values with ozone and hydroxyl radicals (kO3 and kHO•), leading to a characteristic elimination pattern for each group of contaminants. This study demonstrates the high potential of membrane contactors as an appealing alternative for ozone-driven wastewater treatment.

Industrial Sideline Testing of Photocatalytic Equipment for the Treatment of Volatile Organic Compounds

AbstractVolatile organic compounds (VOCs) are the primary pollutant emitted by chemical laboratories, causing significant damage to the environment and posing a serious threat to human health. In this study, an industrial‐scale photocatalytic device was constructed for the removal of VOCs. The effectiveness of the photocatalytic device in removing gases such as ethyl acetate, dichloromethane, petroleum ether, and formaldehyde was investigated. The effects of gas flow rate, inlet concentration, temperature, and relative humidity on photocatalytic purification efficiency were revealed, which laid an important foundation for the further development of the industrial‐scale photocatalytic device.

Saturation of the MEA solution with CO2: Absorption prototype and experimental technique

The carbon dioxide (CO2) emissions from thermoelectric power plants contribute to global warming. The Monoethanolamine (MEA) solution is the most widely used solvent for CO2 removal processes from these power plants with the disadvantage that it is expensive and corrosive at high concentrations. In this work, an experimental methodology is developed to fix the operating flow ratio (L/G) that ensures the maximum absorption capacity of MEA solution. The absorption system prototype and the experimental saturation technique are detailed. The main parameters of the experimental technique were the amount (0.65 and 1.30 kg) and concentrations (10,15, 20, 25, and 30 wt%) of MEA solution with CO2 inlet gas concentration (12.5 vol%). The experimental technique shows that MEA saturation occurs when the maximum temperature increase in the solution. Continuous tests were developed to operate the absorption system with the maximum absorption capacity of the MEA solution. The results show that the temperature increases in the MEA solution are a function of the flow rates (L/G) and the MEA concentration. Furthermore, the density, viscosity, and refractive index of CO2-free and CO2-saturated MEA solution at concentrations of MEA below 30 wt% are also measured in this work.

A complementary VOCs recovery system based on cryogenic condensation and low-temperature adsorption

The control of volatile organic compounds (VOCs) emission has a significant influence on the environment and human health. Liquid nitrogen (LN2) condensation is a highly efficient method for VOCs recovery with a wide range of applications, but it is poor in the treatment of light hydrocarbons, especially methane and ethane, and has some shortcomings such as high emission concentration and large carbon emissions. In this paper, a novel cryogenic condensation system combined with low-temperature adsorption was proposed. The low-temperature exhaust gas treated by cryogenic condensation equipment is introduced into an adsorption bed, resulting in lower temperature and higher adsorption capacity of the adsorption bed, which not only effectively improves the recovery rate of VOCs, but also solves the spontaneous combustion problem caused by the adsorptive heat effect of traditional room-temperature adsorption method. A thermodynamic calculation model was established, and related experimental verifications were carried out. The results show that the economic value of the recovered VOCs condensate is 1.24 times of the cost of consumed LN2 and the carbon emission reduction is 1683 t per year, achieving an acceptable breakthrough time of 16,971 s at an adsorption temperature of 198.15 K exceeding that at 238.15 K by a factor of 16 when the cryogenic condensation temperature is 138.15 K with a 600 m3/h of waste gas. The effects of cryogenic condensation temperature, adsorption temperature, inlet gas concentration, flow rate, and the proportion of components on the system performance are analyzed in detail.

The assessment of response surface methodology (RSM) and artificial neural network (ANN) modeling in dry flue gas desulfurization at low temperatures

The performance of a flue gas desulfurization (FGD) system is characterized by SO2 removal efficiency () and reagent conversion (). Achieving a near-perfect reaction environment has been of concern in dry FGD (DFGD) due to the low reactivity compared to the wet and semi-dry units. This study will appraise output responses using modeling by response surface methodology (RSM) and artificial neural networks (ANN) approaches. The impacts of input parameters like hydration time, hydration temperature, diatomite to hydrated lime (Ca(OH)2), sulfation temperature and inlet gas concentration will be studied using a randomized central composite design (CCD). ANN fitting tool mapped the CCD metadata using the Levenberg-Marquardt (LM) algorithm activated by the hyperbolic tangent (tansig) function. The hidden cells ranged from 7 to 10 to ascertain the effect node architecture on modeling accuracy. Validation of each procedure was assessed using root mean square error (RMSE), mean square error (MSE) and R-Squared studies. The outcomes presented a more accurate 5-10-2 ANN model in the mapping of the DFGD from R2 data of = 0.993 and = 0.9986 with a mapping deviation from the RMSE values of = 0.48465; = 0.44971 and MSE results of = 0.23488; = 0.20229.

Prediction for the Adsorption of Low-Concentration Toluene by Activated Carbon

Activated carbon filters are widely used to remove gaseous pollutants in order to guarantee a healthy living environment. The standard method for evaluating the adsorption performance of filters is conducted at ~100 ppm. Although this accelerates the test and avoids the high requirements of the test device, it is still far from the contaminant concentration in the indoor environment, and adsorbents in practical application may show different capabilities. Therefore, this study compared several methods for predicting the adsorption performance of activated carbon and recommended a procedure based on the Wheeler–Jonas model to estimate the breakthrough curve at low concentrations using experimental data at high concentrations. The results showed that the Langmuir model and Wood–Lodewyckx correlation were the most suitable for obtaining the equilibrium adsorption capacity and mass transfer coefficient, which are critical parameters in the Wheeler–Jonas model. The predicted service life was derived from the breakthrough curve. A modification method based on a relationship with inlet gas concentration was proposed to reduce the prediction deviation of the service life. After modification, the maximum deviation was within two hours and the relative deviation was no more than 7%.

Photocatalytic Degradation of VOC Waste Gas in Petrochemical Sewage Fields

The large amount of waste gas containing volatile organic compounds (VOCs) discharged from petrochemical sewage plants will cause air pollution and seriously endanger the safety of human beings and the ecological environment. In this paper, we proposed a photocatalytic oxidation degradation technique of VOCs and designed a photocatalytic reaction device loaded with TiO2/SnO2 catalyst. Under UV light irradiation, there is an energy level difference in the conduction band between TiO2 and SnO2, which makes the photogenerated electrons (e–) migrate to SnO2 and reduces the surface electron density of TiO2. Thus, the recombination of photogenerated electron–hole pairs (e––h+) is inhibited and the catalyst activity is improved. Meanwhile, the synergistic effect of the oxidation of hydroxyl radicals (·OH) and ozone greatly improves the conversion rate. In addition, in the industrial side line, by studying the influence of inlet gas volume, inlet gas concentration, and gas humidity (RH) on the conversion rate of the VOCs, we revealed the operation law of the photocatalytic technique in industrial applications. Under the best working conditions, the purification rate of the VOCs was as high as 92.73%. This technique can not only effectively avoid the damage to the environment caused by polluting VOCs but also promote the low-carbon and green development of enterprises in the industry.

The use of artificial neural network (ANN) in dry flue gas desulphurization modelling: Levenberg–Marquardt (LM) and Bayesian regularization (BR) algorithm comparison

AbstractThis research project aims to investigate the efficacy of artificial neural networks (ANN) in mapping dry flue gas desulphurization (DFGD). Bayesian regularization (BR) and Levenberg–Marquardt (LM) training algorithms were used for DFGD modelling. The input layer feed data contained diatomite to Ca(OH)2 ratio, hydration time, hydration temperature, sulphation temperature, and inlet gas concentration, while the output layer metadata were sorbent conversion and sulphation responses. The hyperbolic tangent (tansig), sigmoid (logsig), and linear (purelin) activation functions were compared to ascertain the best network learning model. The number of hidden layer cells also varied between 7 and 10, given the existence of multiple output feed data. BR and LM performance evaluation was based on coefficient of determination (R2), root mean square error (RMSE), and mean square error (MSE) mathematical analysis. BR was a superlative training tool compared to LM, with lower RMSE and MSE values. The goodness of fit data for both techniques was close to unity, clarifying that ANN using BR and LM tools can be used to predict DGFD outcome. The shrinking core model was used to analyze the desulphurization reaction and concluding the chemical reaction was the reaction controlling step.

Degradation of oxytetracycline and doxycycline by ozonation: Degradation pathways and toxicity assessment

Tetracyclines are one of the antibiotics widely employed worldwide and frequently detected in surface waters because of incomplete removal from wastewater treatment. Various advanced oxidation processes have been investigated for tetracyclines degradation and their transformation products (TPs) have recently gained more attention. Studies on ozonation are however seldom for the degradation of oxytetracycline (OTC) and doxycycline (DTC). In the present study, a lower O3 inlet gas concentration (4.67 ± 0.13 mg/L), supplied at a flow rate of 0.27 L/min, was shown to be more effective at removing OTC than the same dose of ozone applied at higher inlet gas concentration (up to 6.29 mg/L) over a shorter time at the same flow rate. The use of pCBA and t-BuOH indicated that ozone plays a more important role in the degradation of OTC than HO•. The DTC degradation was less efficient than for OTC, with 99 % removal requiring twice the amount of ozone. OTC had almost no inhibition of Vibrio fischeri, however, the inhibition ratio was increased to 37 % (5-min) and 46 % (15-min) within 1 min of ozonation. Contrastly, DTC had toxic effects on V. fischeri (inhibition rate5min of 84 %) and sustained toxicity in samples treated for up to 40-min. The observed toxicities after treatment could be explained by the identified TPs (26 TPs for OTC and 23 for DTC, some identified for the first time) and their quantitative structure-activity relationship analysis data. Several TPs showed toxic or extremely toxic predicted effects on fish, daphnid, and green algae, corresponding with the V. fischeri inhibition results. Among the possible degradation pathways, aromatic ring hydroxylation and ring-opening pathways could lead to the formation of TPs less harmful to the environment.

Dry scrubbing of gaseous HCl and SO2 with hydrated lime in entrained mixing reactor

The simultaneous dry scrubbing of gaseous HCl and SO2 by hydrated lime in the entrained mixing reactor has been studied at condition of simulating waste incineration flue gas. The entrained mixing reactor combining a numerical optimized entrained mixing up flow reactor with a rectifier for homogeneous flue gas mixing flow distribution were developed as reaction chambers for the dry scrubbing of gaseous HCl and SO2 with hydrated lime powders. The dry scrubbing performance of this technology was experimented at the pilot scale entrained mixing reactor with 0.3 m in diameter of lower part chamber, 1.29 m in diameter of upper part chamber and 6.0 m in total height. Three kind of hydrated lime powders with different surface area and pore volume were injected with carrier compressed air into the reaction chamber for absorption of acid gaseous. The experimental conditions were the following: reaction temperature 180 °C, gas flow rate 1800Nm3/h and HCl and SO2 concentration in inlet gas 250 ppm, respectively, giving different values for the ratio the amount of fresh hydrated lime and acid gaseous concentration at the inlet of reaction chamber and that corresponding to the stoichiometric molar ratio (SR). The gaseous HCl and SO2 removal efficiencies ranged from 89 to 99% and 87 to 99% respectively. The best performance of dry scrubbing was obtained for high surface area and pore volume of the hydrated lime. Increased the surface area and pore volume of hydrated lime improved the removal performance of the gaseous HCl and SO2 as well as the solid reactant conversion. The concentration of HCl and SO2 at the downstream of bag filter was measured to predict the absorption of gaseous HCl and SO2 on the surface of bag filter.

Simultaneous removal of NOx and SO2 from simulated marine ship flue gas in a novel wet scrubbing system based on divided diaphragm seawater electrolysis technology: efficiency optimization and economic assessment.

This work constructed a divided diaphragm seawater electrolysis system with two tandem packed towers for the synergistic removal of NOx and SO2. The first tower was mainly used to oxidize NO and SO2 by AC (active chlorine), and the second tower was used to further absorb NOx. The factors affecting on NO removal, including ACC (active chlorine concentration), pH value, initial NO concentration and temperature in the oxidation tower were investigated. Moreover, the effect of different inlet gas concentrations and current values were explored. The results showed that with the increase of ACC, the NO and NOx removal efficiency increased rapidly, but when the ACC was higher than 500 mg/L [Cl2], the removal efficiency did not increase further in the oxidation tower. Low pH values in the oxidation tower were favorable for NO removal. NO removal efficiency reached a maximum at 40 °C. Higher NO and SO2 concentrations were favorable for NO removal. The decline of pH in the anode cell was not conducive to the storage of AC in the continuous electrolysis removal process. NOx and SO2 were almost completely removed after being scrubbed in the oxidation and absorption towers. The relationship between current and removal efficiency of NO and SO2 in the oxidation tower was also analyzed. Finally, the removal mechanism and the application prospects were discussed.

Model-Based Analysis of Feedback Control Strategies in Aerobic Biotrickling Filters for Biogas Desulfurization

Biotrickling filters are one of the most widely used biological technologies to perform biogas desulfurization. Their industrial application has been hampered due to the difficulty to achieve a robust and reliable operation of this bioreactor. Specifically, biotrickling filters process performance is affected mostly by fluctuations in the hydrogen sulfide (H2S) loading rate due to changes in the gas inlet concentration or in the volumetric gas flowrate. The process can be controlled by means of the regulation of the air flowrate (AFR) to control the oxygen (O2) gas outlet concentration ([O2]out) and the trickling liquid velocity (TLV) to control the H2S gas outlet concentration ([H2S]out). In this work, efforts were placed towards the understanding and development of control strategies in biological H2S removal in a biotrickling filter under aerobic conditions. Classical proportional and proportional-integral feedback controllers were applied in a model of an aerobic biotrickling filter for biogas desulfurization. Two different control loops were studied: (i) AFR Closed-Loop based on AFR regulation to control the [O2]out, and (ii) TLV Closed-Loop based on TLV regulation to control the [H2S]out. AFR regulation span was limited to values so that corresponds to biogas dilution factors that would give a biogas mixture with a minimum methane content in air, far from those values required to obtain an explosive mixture. A minimum TLV of 5.9 m h−1 was applied to provide the nutrients and moisture to the packed bed and a maximum TLV of 28.3 m h−1 was set to prevent biotrickling filter (BTF) flooding. Control loops were evaluated with a stepwise increase from 2000 ppmv until 6000 ppmv and with changes in the biogas flowrate using stepwise increments from 61.5 L h−1 (EBRT = 118 s) to 184.5 L h−1 (EBRT = 48.4 s). Controller parameters were determined based on time-integral criteria and simple criteria such as stability and oscillatory controller response. Before implementing the control strategies, two different mass transfer correlations were evaluated to study the effect of the manipulable variables. Open-loop behavior was also studied to determine the impact of control strategies on process performance variables such as removal efficiency, sulfate and sulfur selectivity, and oxygen consumption. AFR regulation efficiently controlled [O2]out; however, the impact on process performance parameters was not as great as when TLV was regulated to control [H2S]out. This model-based analysis provided valuable information about the controllability limits of each strategy and the impact that each strategy can have on the process performance.

Simultaneous elimination of H2S and NH3 in a biotrickling filter packed with polyhedral spheres and best efficiency in compost deodorization

With polyhedral spheres as the packing, a semi-pilot biological trickling filter reactor (BTF) inoculated by domesticated activated sludge is used to remove Hydrogen Sulphide (H2S) and Ammonia (NH3). The removal rate of H2S and NH3 by BTF was as high as 98.25% and 88.55%, and the maximum removal load was 84.57 g H2S m−3h−1 and 38.77 g NH3 m−3h−1 during the 61-day process. The inlet gas concentration ranges from 0 to 500 ppm, and the empty bed residence time (EBRT) is 31.8 s. When the EBRT reduced from 31.8s to 25.4s, the removal rate of H2S and NH3 decreased significantly, which was 67.21% and 81.36%, respectively. The results showed that EBRT significantly affected the removal rate of H2S and NH3. Microbial analysis indicated that Dokdonella, Ferruginibacter, Nitrosomonas, and Thiobacillus had high abundance at the genus level, showing that these genera play an important role in the degradation of H2S and NH3. When the optimized parameters applied to the on-site biogas residue compost, the removal rate of H2S and NH3 by BTF can reach 91.34%, which provides a feasible process for the deodorization project with compost.

Ozonation of three different fungal conidia associated with apple disease: Importance of spore surface and membrane phospholipid oxidation.

Although ozone (O3) is a well‐known bactericide and fungicide, the required dose of ozone can depend significantly on the targeted pathogens. The present research evaluates the variation in sensibility to ozone of three fungal species from a single fungal group. The three fungal species selected, Venturia inaequalis, Botrytis cinerea, and Neofabreae alba, belong to the Ascomycota group and attack apples. The fungi were exposed to ozone by bubbling directly into the spore solutions (treatment period ranged from 0.5 to 4 min, ozone concentration in inlet gas ranged from 1 to 30 g/m3). The rates of germination were determined, and the level of peroxidation of the lipid membrane was quantified based on the malondialdehyde (MDA) production. The results indicate that ozone effectively reduces spore development and suggest that the fungi differ in sensitivity. To reduce by 50% the spore germination rate of N. alba, B. cinerea, and V. inaequalis requires ozone doses of 0.01, 0.03, and 0.07 mg/ml, respectively. Spore sensitivity seems to be directly linked to spore surface. For all the fungal species, the MDA level and the level of spore inactivation both increase with ozone dose, which confirms that ozone alters the cell membrane.

Numerical and experimental analysis of optimized conical flask photobioreactor structures to improve liquid–gas two-phase distribution and microalgae carbon sequestration

In this paper, light intensity and gas–liquid distribution of microalgae in the original conical flask photobioreactor with central inlet tube bubbling ventilation are studied by applying both numerical simulation and experimental analysis. The different optimized structures of conical flask photobioreactors are proposed to improve light distribution and microalgae carbon fixation. The advanced effects of light intensity and gas–liquid distribution in advanced conical flask reactors are validation by 5 important parameters. First, the Eulerian gas–liquid two-phase model and DO (Discrete Ordinate) light distribution model of the conical flask reactor are developed. Gas distribution and light distribution are analyzed with different conditions of gas inlet velocity. Second, the optimal gas inlet velocity is evaluated with five vital parameters (average velocity, turbulent kinetic energy, gas holdup rate, average light intensity and velocity of the vertical wall). Then, the optimal CO2 gas inlet concentration is determined by a series of controlled experiment test groups. Finally, based on the numerical simulation and experiment result, three different optimized structures of conical flasks are proposed to prove the effectiveness of optimization, which is named lean-insertion bottle, baffle bottle and cross-nozzle bottle. The results showed that 0.5 m·s−1 gas inlet velocity is the optimal value for the gas–liquid distribution in the 500 ml conical flask reactor. With the increase of CO2 concentration, the growth rate of microalgae biomass concentration increased first and then decreased after the concentration arrives at 4%. At 4% CO2 gas inlet concentration, the highest biomass concentration is increased by 57.4% compared with the lowest ones. The gas distribution and light distribution in the three optimized reactors are significantly improved, and among the three optimizations, the PBR with baffle at 0 mm of the gas inlet pipe is the best one. In conclusion, the cultivation condition of microalgae and the structure of algae photobioreactors are both optimized providing a novel beneficial reference to improve the liquid–gas distribution and carbon sequestration rate of microalgae growth in the laboratory.

Ionic-Liquid-Based Contactors for Carbon Dioxide Removal from Simulated Spacecraft Cabin Atmospheres

The ionic liquid, 1-butyl-3-methylimidazolium acetate ([bmim][Ac]), was used to remove carbon dioxide () from a simulated spacecraft cabin atmosphere (2 mm Hg (267 Pa)) partial pressure of with balance of nitrogen (630 mm Hg total pressure). Three gas–liquid contactor configurations were experimentally characterized to measure the rates of removal from the simulated atmosphere with [bmim][Ac]. Two of the contactors, a parallel path flat plate and hollow fiber membrane, used hydrophobic porous membranes (silicone and polypropylene, respectively) to separate the gas and ionic liquid streams. The third, a three-dimensional printed interior-corner capillary-driven contactor, was configured for the crossflow of gas directly over the free liquid surface. At circa liquid flow and gas flow rate (0.24 slpm), inlet and outlet concentration differentials in the gas flow were 990, 2420, and for the flat plate, hollow fiber, and interior-corner contactors, respectively. For these same contactors, the removal rates were (), (), and , respectively. Overall mass transfer coefficients were (), (), and ( for each contactor, respectively. The coefficients generally decreased in direct proportion to increased gas flow. These performance metrics were nearly insensitive to variations in the flow of ionic liquid. The maximum uptake of by [bmim][Ac] was measured at 7.45 w% at and room temperature (23°C). The loading was 1.67 w% when exposed to the simulated spacecraft cabin atmosphere. In addition, desorption with thermal vacuum and thermal sparge processes were studied at temperatures from 20 to 80°C, the latter using dry inert gases (argon and nitrogen) to remove from the ionic liquid. After 4 h at 71°C under rough vacuum (0.5 mm Hg) without stirring, gravimetric measurements indicated a decrease in loading of from 1.75 w% to 1.29 w%. In comparison, for a gas sparge flow through -saturated [bmim][Ac] at 65°C, the loading decreased from 1.67 w% to 0.75 w% over the same period. The results suggest the importance of elevated temperature coupled with agitation to increase the rate of desorption from the ionic liquid.

NO Separation Characteristics in Integrated Electromigration Membrane Reactor

An integrated electromigration membrane absorption method has been proposed for the separation of NO from simulated mixed gas. The experiments were conducted to investigate the effect of discharge voltage, gas flow rate, inlet concentrations, and absorbents on the NO separation efficiency and total mass transfer coefficient in the integrated electromigration membrane reactor. The experimental results demonstrated that the NO separation efficiency and total mass transfer coefficient increased with the increase in the applied discharge voltage of the integrated electromigration membrane reactor. Regardless of discharge or not, the separation efficiency of NO continuously decreased with the increase in the gas flow rate and inlet concentration of NO in the experimental process. The total mass transfer coefficient of NO increased first and then decreased with an increase in the gas flow rate, while it decreased with an increase in NO inlet concentration. Compared with the membrane absorption without discharge voltage under the condition tested, at a discharge voltage of 18kV, the NO separation efficiency and the total mass transfer coefficient increased by 48.7% and 9.7 times, respectively.

Research into the simultaneous removal process of H2S and PH3 by Cu–Fe–Ce composite metal oxide adsorbent

In this study, a Cu–Fe–Ce composite metal oxide adsorbent was synthesized by chemical precipitation method to simultaneously remove H2S and PH3. The effects of reaction temperature, oxygen content, gas inlet concentration and gas hourly space velocity (GSHV) were studied. The DRIFTS results showed that excessive oxygen and high reaction temperature lead to excessive conversion of H2S, which competed with adsorption–oxidation of PH3, and it was not conducive to simultaneous removal of H2S and PH3, and it was found that high concentration of H2S was more likely to cause deactivation of the adsorbent than PH3. GHSV affected the contact time between the adsorbent and the gas and affected the removal effect. The BET results showed that a larger specific surface area was more conducive to gas adsorption, and thus had a better removal effect. The XPS results showed that the deactivation of the adsorbent was due to the formation of sulfur-containing and phosphorus-containing substances.