Dianhua Liu

Mathematical Simulation and Design of Three-Phase Bubble Column Reactor for Direct Synthesis of Dimethyl Ether from Syngas

Abstract A three-phase reactor mathematical model was set up to simulate and design a three-phase bubble column reactor for direct synthesis of dimethyl ether (DME) from syngas, considering both the influence of part inert carrier backmixing on transfer and the influence of catalyst grain sedimentation on reaction. On the basis of this model, the influences of the size and reaction conditions of a 100000 t/a DME reactor on capacity were investigated. The optimized size of the 10000 t/a DME synthesis reactor was proposed as follows: diameter 3.2 m, height 20 m, built-in 400 tube heat exchanger (ϕ 38×2 mm), and inert heat carrier paraffin oil 68 t and catalyst 34.46 t. Reaction temperature and pressure were important factors influencing the reaction conversion for different size reactors. Under the condition of uniform catalyst concentration distribution, higher pressure and temperature were proposed to achieve a higher production capacity of DME. The best ratio of fresh syngas for DME synthesis was 2.04.

Intrinsic kinetics of methane aromatization under non-oxidative conditions over modified Mo/HZSM-5 catalysts

The intrinsic reaction kinetics of methane aromatization under non-oxidative conditions over modified Mo/HZSM-5 catalysts was studied in the quartz pipe-reactor under ordinary pressure with the temperature ranging from 913.15 to 973.15 K and the space velocity from 700 to 2100 ml/(g·h). The Langmuir-Hinshelwood model was chosen to describe the intrinsic kinetics while Levenberg-Marquardt method was selected to determine the parameters in the kinetic model. Statistical test and residual error distribution diagrams showed that experimental data were in good agreement with calculated data, and Langmuir-Hinshelwood model was suitable for the description of the intrinsic kinetics of methane aromatization under the reaction conditions discussed in this article.

Synthesis of ethylidene diacetate from dimethyl ether, CO and H2

Abstract Ethylidene diacetate was prepared by reacting dimethyl ether, acetic acid and syngas in the presence of a catalytic system comprising RhI 3 , PPh 3 and CH 3 I. The effects of reaction temperature, pressure, time and the CO/H 2 molar ratio on the conversion of dimethyl ether and the product selectivity were investigated under the same catalyst formulation. Results showed that a maximum conversion of dimethyl ether was obtained when a mixture consisting of 0.3 mol dimethyl ether and 120 ml acetic acid was reacted at 180 °C and 3.0 MPa for 10 h at a stirring speed of 600 rpm under a syngas flow with a CO/H 2 molar ratio of 2.5, which was catalyzed by a catalyst mixture comprising 0.3 g RhI 3 , 6g PPh 3 and1.3gCH 3 I. The selectivity of ethylidene diacetate increased with temperature, decreased with the CO/H 2 molar ratio and exhibited a maximum with pressure.