Yaneeporn Patcharavorachot

Analysis of hydrogen production from methane autothermal reformer with a dual catalyst-bed configuration

This paper presents a performance analysis of a dual-bed autothermal reformer for hydrogen production from methane using a non-isothermal, one dimensional reactor model. The first section of Pt/Al2O3 catalyst is designed for oxidation reaction, whereas the second one based on Ni/MgAl2O4 catalyst involves steam reforming reaction. The simulation results show that the dual-bed autothermal reactor provides higher reactor temperature and methane conversion compared with a conventional fixed-bed reformer. The H2O/CH4 and O2/CH4 feed ratios affect the methane conversion and the H2/CO product ratio. The addition of steam at lower temperatures to the steam reforming section of the dual-bed reactor can produce the synthesis gas with a higher H2/CO product ratio.

Hybrid Process of Reactive Distillation and Pervaporation for the Production of Tert-amyl Ethyl Ether

Abstract In this study, a reactive distillation column in which chemical reaction and separation occur simultaneously is applied for the synthesis of tert -amyl ethyl ether (TAEE) from ethanol (EtOH) and tert -amyl alcohol (TAA). Pervaporation, an efficient membrane separation technique, is integrated with the reactive distillation for enhancing the efficiency of TAEE production. A user-defined Fortran subroutine of a pervaporation unit is developed, allowing the design and simulation of the hybrid process of reactive distillation and pervaporation in Aspen Plus simulator. The performance of such a hybrid process is analyzed and the results indicate that the integration of the reactive distillation witfi the pervaporation increases the conversion of TAA and the purity of TAEE product, compared with the conventional reactive distillation.

Using a membrane reactor for the oxidative coupling of methane: simulation and optimization

An oxidative coupling of methane (OCM) is a promising process to convert methane into ethylene and ethane; however, it suffers from the relatively low selectivity and yield of ethylene at high methane conversion. In this study, a membrane reactor is applied to the OCM process in order to prevent the deep oxidation of a desirable ethylene product. The mathematical model of OCM process based on mass and energy balances coupled with detailed OCM kinetic model is employed to examine the performance of OCM membrane reactor in terms of CH4 conversion, C2 selectivity, and C2 yield. The influences of key operating parameters (i.e., temperature, methane-to-oxygen feed ratio, and methane flow rate) on the OCM reactor performance are further analyzed. The simulation results indicate that the OCM membrane reactor operated at higher operating temperature and lower methane-to-oxygen feed ratio can improve C2 production. An optimization of the OCM membrane reactor using a surface response methodology is proposed in this work to determine its optimal operating conditions. The central composite design is used to study the interaction of process variables (i.e., temperature, methane-to-oxygen feed ratio, and methane flow rate) and to find the optimum process operation to maximize the C2 products yield.

Effect of Flow Pattern on Single and Multi-stage High Temperature Proton Exchange Membrane Fuel Cell Stack Performance

A high-temperature proton exchange membrane fuel cell (HT-PEMFC) is a promising clean and effective technology for power generation because of its simplified water and heat management as well as high CO tolerance. Therefore, it could be possible to directly use a reformate gas for HT-PEMFC without the need for sophisticated purification processes. Due to the non-uniform of H2 and CO distributions within fuel cells, the stack design is one of the key factors to enhance the performance and efficiency of HT-PEMFC. In this study, a single HT-PEMFC stack is investigated by considering the CO poisoning effect. The mathematical model of HT-PEMFC based on the electrochemical reaction model coupled with the diffusion model of a gas diffusion layer and electrolyte film layer is used for simulation studies. At high fuel utilization, hydrogen is highly consumed and CO concentration increases, having a significant impact on cell performance. The multi-stack HT-PEMFC is designed to minimize the CO poisoning effect and to maximize its efficiency. The power output that is obtained from each cell stack is presented and the overall power output is compared with single cell stack. Effect of different flow patterns, i.e., co-current and counter-current flow, on the HT-PEMFC stack performance is also presented.