Comparative modeling study of catalytic membrane reactor configurations for syngas production by CO 2 reforming of methane

Energy and exergy optimization of oxidative steam reforming of acetone–butanol–ethanol–water mixture as a renewable source for H2 production via thermodynamic modeling

Acetone–butanol–ethanol–water mixture is obtained by fermentation of biomass namely, corncob, wheat straw, sugarbeets, sugarcane, etc. For using the individual components, one alternative is to separate the mixture by distillation, which is costly and energy intensive operation. This paper proposes its other use in available conditions to produce hydrogen fuel by oxidative steam reforming process. For the proposed process, thermodynamic equilibrium modeling has been performed by using non-stoichiometric approach of Gibbs free energy minimization. The compositions of acetone, butanol and ethanol in mixture are 0.33:0.52:0.15 on molar basis. The influence of pressure (1–10 atm), temperature (573–1473 K), steam to ABE mixture molar feed ratio (F ABE = 5.5–8.5), and oxygen to ABE mixture molar feed ratio (F OABE = 0.25–1) have been tested by simulations on the yield of products (at equilibrium) namely, H2, CH4, CO2, CO, and carbon as solid. The optimum conditions for maximum production of desired H2, minimization of undesired CH4, and elimination of carbon (solid) formation are T = 973 K, P = 1 atm, F ABE = 8.5, and F OABE = 0.25. Under same operating conditions, the maximum generation of H2 is 7.51 on molar basis with negligible carbon formation. The total energy requirement for the process (295.73 kJ/mol), the energy required/mol of hydrogen (39.37 kJ), and thermal efficiency (68.09%) of the reformer have been obtained at same operating conditions. The exergy analysis has also been investigated to measure the work potential of the energy implied in the reforming process.

State-of-the-art in methane-reforming reactor modeling: challenges and new insights

The reforming of methane is an important industrial process, and reactor modeling and simulation is frequently employed as a design and analysis tool in understanding this process. While much research work is devoted to catalyst formulations, reaction mechanisms, and reactor designs, this review aims to summarize the literature concerning the simulation of methane reforming. Applications in industrial practice are highlighted, and the three main approaches to representing the reactions are briefly discussed. An overview of simulation studies focusing on methane reforming is presented. The three central methods for fixed-bed reactor modeling are discussed. Various approaches and modern examples are discussed, presenting their modeling methods and key findings. The overall objective of this paper is to provide a dedicated review of simulation work done for methane reforming and provide a reference for understanding this field and identifying possible new paths.

Modeling of dry reforming of methane for hydrogen production at low temperatures using membrane reactor

The hydrogen removal and carbon formation effects in dense palladium (Pd)-based membrane reactors for dry reforming of methane (DRM) performance is numerically analyzed in this study. The steady-state membrane reactor operation is described using a three-dimensional, heterogeneous, non-isothermal mathematical model. Based on the numerical simulation results for reaction temperature and pressure varied in the 400–600 °C and 1–30 atm ranges, methane conversion and hydrogen yield were found enhanced using the membrane reactor. However, carbon formation, which affects catalyst activity and limits the benefits of using a membrane reactor is also enhanced. A parametric study using reaction pressure as the primary parameter for the membrane reactor operation found that the CH4 conversion, hydrogen yield, H2 recovery, and carbon formation can be enhanced by increasing the reaction temperature, inlet CO2/CH4 ratio, and sweep gas flow rate. With the enhanced H2 removal, carbon formation is also enhanced. Because membrane permeance is inversely proportional to the membrane thickness, membrane thickness can be used as a parameter to control the carbon formation under given operating conditions.