Simultaneous generation of electricity, ethylene and decomposition of nitrous oxide via protonic ceramic fuel cell membrane reactor

Ethylene,one of the most widely produced building blocks in the petrochemical industry,has received intense attention.Ethylene production,using electrochemical hydrogen pump-facilitated nonoxidative dehydrogenation of ethane(NDE)to ethylene,is an emerging and promising route,promoting the transformation of the ethylene industry from energy-intensive steam cracking process to new electrochemical membrane reactor technology.In this work,the NDE reaction is incorporated into a BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ)electrolyte-supported protonic ceramic fuel cell membrane reactor to co-generate electricity and ethylene,utilizing the Nb and Cu doped perovskite oxide Pr_(0.6)Sr_(0.4)Fe_(0.8)Nb_(0.1)Cu_(0.1)O_(3-δ)(PSFNCu)as anode catalytic layer.Due to the doping of Nb and Cu,PSFNCu was endowed with high reduction tolerance and rich oxygen vacancies,showing excellent NDE catalytic performance.The maximum power density of the assembled reactor reaches 200 mW cm^(-2)at 750℃,with high ethane conversion(44.9%)and ethylene selectivity(92.7%).Moreover,the nitrous oxide decomposition was first coupled in the protonic ceramic fuel cell membrane reactor to consume the permeated protons.As a result,the generation of electricity,ethylene and decomposition of nitrous oxide can be simultaneously obtained by a single reactor.Specifically,the maximum power density of the cell reaches 208 mW cm^(-2)at 750℃,with high ethane conversion(45.2%),ethylene selectivity(92.5%),and nitrous oxide conversion(19,0%).This multi-win technology is promising for not only the production of chemicals and energy but also greenhouse gas reduction.

Electrodeposition conditions of metallic nickel in electrolytic membrane reactor

The process parameters were optimized for the eleetrodeposition of nickel in an electrolytic membrane reactor. Nickel（Ⅱ） and boric acid concentrations, pH and temperature were varied to evaluate the changes in current efficiency and specific energy consumption of nickel electrodeposition. The catholyte was aqueous nickel（Ⅱ） sulfate and boric acid, and the anolyte was sulfuric acid solution. An anionic membrane separated the anolyte from the catholyte while maintained a conductive path between the two compartments. The results indicated that the cathode current efficiency increased with the increase of nickel concentration, pH and boric acid concentration, and decreased with the increase of current density and stirring rate. A maximum current efficiency of 97.15% was obtained under the optimized conditions of electrolyte composition of 40 g/L Ni and 40 g/L boric acid at temperature of 42 ℃ and pH of 6 with a cathode current density of 300 A/m2.

Partial oxidation of simulated hot coke oven gas to syngas over Ru-Ni/Mg(Al)O catalyst in a ceramic membrane reactor

Hydrogen amplification from simulated hot coke oven gas （HCOG） was investigated in a BaCo0.7Fe0.2Nb0.1O3-δ （BCFNO） membrane reactor combined with a Ru-Ni/Mg（Al）O catalyst by the partial oxidation of hydrocarbon compounds under atmospheric pressure. Under optimized reaction conditions, the dense oxygen permeable membrane had an oxygen permeation flux around 13.3 ml/（cm^2·min）. By reforming of the toluene and methane, the amount of H2 in the reaction effluent gas was about 2 times more than that of original H2 in simulated HCOG. The Rn-Ni/Mg（Al）O catalyst used in the membrane reactor possessed good catalytic activity and resistance to coking. After the activity test, a small amount of whisker carbon was observed on the used catalyst, and most of them could be removed in the hydrogen-rich atmosphere, implying that the carbon deposition formed on the catalyst might be a reversible process.

Performance of a tubular oxygen-permeable membrane reactor for partial oxidation of CH_4 in coke oven gas to syngas

A gas-tight BaCo 0.7 Fe 0.2 Nb 0.1 O 3-δ（BCFNO） tubular membrane was fabricated by hot pressure casting.And a membrane reactor with BCFNO tubular membrane and Ag-based sealant was readily constructed and applied to partial oxidation of CH4 in coke oven gas.At 875 ℃,95% of methane conversion,91% of H 2 and as high as 10 ml cm-2·min-1 of oxygen permeation flux were obtained.There was a good match in the coefficient of thermal expansion between Ag-based alloy and BCFNO membrane materials.The tubular BCFNO membrane reactor packed with Ni-based catalysts exhibited not only high activity but also good stability in hydrogen-enriched coke oven gas（COG） atmosphere.

Syngas Production Using an Oxygen-Permeating Membrane Reactor with Cofeed of Methane and Carbon Dioxide

CH4-CO2-O-2 reforming to syngas in a never Ba0.5Sr0.5Co0.8Fe0.2O3.delta oxygen-permeable membrane reactor using LiLaNiO/gamma-Al2O3 as catalyst was successfully reported. Excellent reaction performance was achieved with around 92% methane conversion efficiency, 95% CO2 conversion rate, and nearly 8.5mL/min.cm(2) oxygen permeation flux. In contrast to the oxygen permeation model with the presence of large concentration of CO2 (under such condition the oxygen permeation flux deteriorates with time), the oxygen permeation flux is really stable under the CH4CO2-O-2 reforming condition.

Methane Conversion to C_2 Hydrocarbons in Solid State Oxide Electrolyte Membrane Reactor

Provskite-type catalysts, Ln0.6 Sr0.4 FexCo1-x O3 (Ln = Nd,Pr, Gd, Sm, La, 0＜x＜1) and Ln0.8Na0.2CoO3(Ln= La,Gd, Sm) were synthesized, their catalytic properties in the oxidative coupling of methane (OCM) were examined in a fixed-bed reactor. The former group presented higher activity in the OCM, but the main product was carbon dioxide. While the later group showed lower activity but much higher selectivity to C2 hydrocarbons compared with the former. Electrochemical measurements were conducted in a solid oxide membrane reactor with La0.8 Na0.2CoO3 as catalyst. The results showed that methane was oxidized to carbon dioxide and ethane by two parallel reactions. Ethane was oxidized to ethene and carbon dioxide. A fraction of ethene was oxidized deeply to carbon dioxide. The total selectivity to C2 hydrocarbons exceeded 70%. Based on the experimental results, a kinetic model was suggested to describe the reaction results.

Effect of hydrogen combustion reaction on the dehydrogenation of ethane in a fixed-bed catalytic membrane reactor

A two-dimensional non-isothermal mathematical model has been developed for the ethane dehydrogenation reaction in a fixed-bed catalytic membrane reactor. Since ethane dehydrogenation is an equilibrium reaction,removal of produced hydrogen by the membrane shifts the thermodynamic equilibrium to ethylene production.For further displacement of the dehydrogenation reaction, oxidative dehydrogenation method has been used.Since ethane dehydrogenation is an endothermic reaction, the energy produced by the oxidative dehydrogenation method is consumed by the dehydrogenation reaction. The results show that the oxidative dehydrogenation method generated a substantial improvement in the reactor performance in terms of high conversions and signi ficant energy saving. It was also established that the sweep gas velocity in the shell side of the reactor is one of the most important factors in the effectiveness of the reactor.

Tubular electrocatalytic membrane reactor for alcohol oxidation：CFD simulation and experiment

A functional electrocatalytic membrane reactor(ECMR) was performed for the electrocatalytic oxidation of2,2,3,3-tetrafluoro-l-propanol(TFP) into high value-added sodium 2,2,3,3-tetrafluoropropionate(STFP),A computational fluid dynamics(CFD) technique was applied to simulate the hydrodynamic distributions along a tubular ECMR so as to provide guidance for the design and optimization of ECMR Two-dimensional simulation with porous media model was employed to predict the properties of fluid dynamics in ECMR.The experimental investigation was carried to confirm the CFD simulation.Results showed that a uniform distribution of permeate velocity along the tubular reactor with short length and large diameter could be obtained.TFP conversion of97.7%,the selectivity to STFP of 99.9%and current efficiency of 40.1%were achieved from the ECMR with a length of 40 mm and an inside diameter of 53 mm.The simulations were in good agreement with the experimental results.

Oxidative Dehydrogenation of Alkanes using Oxygen-Permeable Membrane Reactor

The oxidative dehydrogenation （ODH） reactions of ethane and propane were investigated in a catalytic membrane reactor, incorporating oxygen-permeable membranes based upon La2Ni0.9V0.1O4＋δor Ba0.5Sr0.5Co0.8Fe0.2O3-δ. As a compromise between the occurrence of a measureable oxygen flux and excessive homogenous gas phase reactions, the measurements were conducted at an intermediate temperature, either at 550 or 650 oC. The results show the dominating role of the oxygen flux across the membrane and available sites at the membrane surface in primary activation of the alkane and, hence, in achieving high alkane conversions. The experimental data of ODH of propane and ethane on both membrane materials can be reconciled on the basis of Mars-van Krevelen mechanism, in which the alkane reacts with lattice oxygen on the membrane surface to produce the corresponding olefin. It is further demonstrated that the oxygen concentration in the gas phase and on the membrane surface is crucial for determining the olefin selectivity.

Progress in catalytic membrane reactors for removing sulfur from natural gas

Increasingly high requirement driven by environmental concern leads to more rigorous standards for sulfur dosage in fuel. Natural gas desulfurization is an important unit for industrial natural gas process. Catalytic membrane reactor for sulfur compounds removal is a newly emerged and integrated membrane technology. We reviewed the current progress for desulfurization of natural gas with membrane process, and predicted that the process combined with catalytic membrane reactor and microwave irradiation for desulfurization of natural gas might be an integrated and promising unit for large scale desulfurization with high efficiency.

Methane Aromatization Upgraded by Oxygen-Permeable Membrane Reactor

Recently the CAS Qingdao Institute of Bioenergy and Processes in collaboration with the Leibniz Universit?t Hannover,Forschungszentrum Jülich and Bayer AG has made attempts to carry out methane aromatization reaction in an oxygen-permeable membrane reactor to

Design of two-stage membrane reactor for the conversion of coke-oven gas to H_2 and CO

The catalyst function was achieved in two regions in an oxygen permeation membrane reactor： H2 dissociated and reacted with lattice oxygen or oxygen ions to form H20 near the membrane surface. The H20 formed could react with the residual CH4 away from the membrane surface area.

Progress on Porous Ceramic Membrane Reactors for Heterogeneous Catalysis over Ultrafine and Nano-sized Catalysts

Heterogeneous catalysts with ultrafine or nano particle size have currently attracted considerable attentions in the chemical and petrochemical production processes, but their large-scale applications remain challenging because of difficulties associated with their efficient separation from the reaction slurry. A porous ceramic membrane reactor has emerged as a promising method to solve the problem concerning catalysts separation in situ from the reaction mixture and make the production process continuous in heterogeneous catalysis. This article presents a review of the present progress on porous ceramic membrane reactors for heterogeneous catalysis, which covers classification of configurations of porous ceramic membrane reactor, major considerations and some important industrial applications. A special emphasis is paid to major considerations in term of application-oriented ceramic membrane design, optimization of ceramic membrane reactor performance and membrane fouling mechanism. Finally, brief concluding remarks on porous ceramic membrane reactors are given and possible future research interests are also outlined.

Hydrogen production from coke oven gas over LiNi/γ-Al_2O_3 catalyst modified by rare earth metal oxide in a membrane reactor

The performance of LiNi/γ-Al2O3 catalysts modified by rare earth metal oxide （La2O3 or CeO2） packed on BCFNO membrane reactor was discussed for the partial oxidation of methane （POM） in coke oven gas （COG） at 875 ℃. The NiO/γ-Al2O3 catalysts with different amounts of La2O3 and CeO2 were prepared with the same preparation method and under the same condition in order to compare the reaction performance （oxygen permeation, CH4 conversion, H2 and CO selectivity） on the membrane reactor. The results show that the oxygen permeation flux increased significantly with LiNiREOx/γ-Al2O3 （RE = La or Ce） catalysts by adding the element of rare earth especially the Ce during the POM in COG. Such as, the Li15wt%CeO29wt%NiO/γ-Al2O3 catalyst with an oxygen permeation flux of 24.71 ml·cm^-2·min^-1 and a high CH4 conversion was obtained in 875 ℃. The resulted high oxygen permeation flux may be due to the added Ce that inhibited the strong interaction between Ni and Al2O3 to form the NiAl2O4 phase. In addition, the introduction of Ce leads up to an important property of storing and releasing oxygen.

One-step Continuous Phenol Synthesis Technology via Selective Hydroxylation of Benzene over Ultrafine TS-1 in a Submerged Ceramic Membrane Reactor

A new route towards phenol production by one-step selective hydroxylation of benzene with hydrogen peroxide over ultrafine titanium silicalites-1(TS-1) in a submerged ceramic membrane reactor was developed, which can maintain the in situ removal of ultrafine catalyst particles from the reaction slurry and keep the process continuous.The effects of key operating parameters on the benzene conversion and phenol selectivity, as well as the membrane filtration resistance were examined by single factor experiments. A continuous reaction process was carried out under the obtained optimum operation conditions. Results showed that the system can be continuously and stably operated over 20 h, and the benzene conversion and phenol selectivity kept at about 4% and 91%, respectively. The ceramic membrane exhibits excellent thermal and chemical stability in the continuous reaction process.

Partial oxidation of methane in Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.1)Ni_(0.1)O_(3-δ) ceramic membrane reactor

Ba0.5Sr0.5Co0.8Fe0.1Ni0.1O3δ（BSCFNiO） perovskite oxides were synthesized using a combined EDTA-citrate complexation method,and then pressed into disk and applied in a membrane reactor.The performance of the BSCFNiO membrane reactor was studied for partial oxidation of methane over Ni/α-Al 2 O 3 catalyst.The time dependence of oxygen permeation rate and catalytic performance of BSCFNiO membrane during the catalyst initiation stage were investigated at 850 C.In unsteady state,oxygen permeation rate,methane conversion and CO selectivity were closely related to the state of the catalyst.After 300 min from the initial time,the reaction condition reached to steady state and oxygen permeation rate were obtained about 11.7cm 3 cm 2 min 1.Also,the performance of membrane reactor was studied at the temperatures between 750 and 950 C.The results demonstrated good performance for the membrane reactor,as CH 4 conversion and CO selectivity permeation rate reached 98% and 97.5%,respectively,and oxygen permeation rate was about 14.5 cm 3 cm 2 min 1 which was 6.8 times higher than that of air-helium gradient.Characterization of membrane surface by SEM after reaction showed that the original grains disappeared on both surfaces exposed to the air and reaction side,but XRD profile of the polished surface membrane indicated that the membrane bulk preserved the perovskite structure.

Design and Fabrication of Ceramic Catalytic Membrane Reactors for Green Chemical Engineering Applications

Catalytic membrane reactors(CMRs),which synergistically carry out separations and reactions,are expected to become a green and sustainable technology in chemical engineering.The use of ceramic membranes in CMRs is being widely considered because it permits reactions and separations to be carried out under harsh conditions in terms of both temperature and the chemical environment.This article presents the two most important types of CMRs:those based on dense mixed-conducting membranes for gas separation,and those based on porous ceramic membranes for heterogeneous catalytic processes.New developments in and innovative uses of both types of CMRs over the last decade are presented,along with an overview of our recent work in this field.Membrane reactor design,fabrication,and applications related to energy and environmental areas are highlighted.First,the configuration of membranes and membrane reactors are introduced for each of type of membrane reactor.Next,taking typical catalytic reactions as model systems,the design and optimization of CMRs are illustrated.Finally,challenges and difficulties in the process of industrializing the two types of CMRs are addressed,and a view of the future is outlined.

Studies of the Methane Steam Reforming Reaction at High Pressure in a Ceramic Membrane Reactor

The effects of temperature and pressure on the steam reforming of methane （CH4＋H2O→← 3H2＋CO） were investigated in a membrane reactor （MR） with a hydrogen permeable membrane. The studies used a novel silica-based membrane prepared by using the chemical vapor deposition （CVD） technique with a permeance for H2 of 6.0×10^-8 mol·m^-2.s^-1.Pa^-1 at 923 K. The results in a packed-bed reactor （PBR） were compared to those of the membrane reactor at various temperatures （773-923 K） and pressures （1-20 atm, 101.3-2026.5 kPa） using a commercial Ni/MgAl2O4 catalyst. The conversion of methane was improved significantly in the MR by the countercurrent removal of hydrogen at all temperatures and allowed product yields higher than the equilibrium to be obtained. Pressure had a positive effect on the hydrogen yield because of the increase in driving force for the permeance of hydrogen. The yield of hydrogen increased with pressure and reached a value of 73× 10^-6 mol·g^-1 .s^-1 at 2026.5 kPa and 923 K which was higher by 108% than the value of 35×10^-6 mol·g^-1.s^-1 obtained for the equilibrium yield. The results obtained with the silica-based membrane were similar to those obtained with various other membranes as reported in the literature.

Preparation of 6-APA by Enzymatic Bioconversion in an Emulsion Liquid Membrane Reactor

Production of 6-aminopenicillanic acid (6-APA) by hydrolysis using penicillin acylase (PA) was studied as a model of an enzymatic emulsion liquid membrane (ELM) process. The loss of PA activity was examined for various membrane compositions (organic solvent, surfactant, carrier). The effects of some experimental variables on the stability of emulsion were investigated. It was found that the choice of organic solvent greatly affected the stability of the emulsion. Increasing the concentration of the carrier in the membrane phase increases the transfer rate of substrate and products but also has a destabilizing effect on the emulsion. The recovery of 6-APA obtained by a di-carrier system (N263-N1923) was much higher than those when either of the di-carriers was used separately. The whole process was controlled both by the enzymatic reaction rate and by the transfer rate of the substrate and the products, however, the ratio of them could be changed by varying the composition of the system. For an optimum condition, it was obtained that the recovery ratio of 6-APA was over 80% and the conversion of benzyl penicillin (PG) was up to 90% in the external phase after 30 minutes. Meanwhile, the breakage percentage of the emulsion was less than 2%.

Chlorine-free emission disposal of spent acid etchant in a three-compartment ceramic membrane reactor

Electrochemical technologies for the on-site treatment of spent acid etchant have received great attention due their ease of operation and economic benefits. On the other hand, a large amount of Cl2 is generated during the electrolysis process, which leads to potential environmental risks. In the present work, a novel threecompartment ceramic membrane flow reactor, including a cathode chamber, an anode chamber, and a gas absorption chamber was developed. The three chambers were divided by an Al2O3 ceramic membrane and a breathable hydrophobic anode diffusion electrode(ADE). The Cl2 evolution onset potential of the ADE was increased to 1.19 V from 1.05 V of the graphite felt, effectively inhibiting the chlorine evolution reaction(CER).The anode-generated Cl2 diffused into the gas absorption chamber through the ADE and was eventually consumed by the H2O2 adsorbent. Cu could be recovered without emitting chlorine due to the special structure of reactor. The current efficiency of copper precipitation and cathode reduction from Cu2+to Cu+reached 97.7%at a working current of 150 m A. These results indicated that the novel membrane reactor had high potential for application in the copper recovery industry.