Erzeng Xue

Water-gas shift conversion using a feed with a low steam to carbon monoxide ratio and containing sulphur

Based on thermodynamic calculations a discussion was given on the need for operation of the water-gas shift (WGS) reaction with a low H2O/CO ratio when a H2-separation membrane is combined with the reaction and on the degree of possible formation of C and CH4 as the result of side reactions occurring in the mixture of CO, H2O, CO2 and H2 under WGS conditions. The behaviour of a number of materials including FeCr, CuZn, CoCr and Pt/ZrO2 were examined under the conditions where the ratio of H2O to CO in the feed was low, with and without the presence of H2S in the feed. The experimental results suggested that Pt/ZrO2 has potential for use in these conditions.

Catalytic oxidation of butane to maleic anhydride enhanced yields in the presence of CO2 in the reactor feed

Abstract The addition of CO 2 to the reaction mixture for the oxidation of butane over a VPO catalyst gives rise to significantly improved yields of maleic anhydride.

Catalysis with membranes or catalytic membranes

Abstract This paper considers the application of inorganic membranes in conjunction with catalysis and discusses attempts which have been made to affect changes in the yields and product distributions in a number of catalytic reactions with a number of different conformations of catalyst and membrane. Various possible reactor conformations are first considered and then some results obtained for catalytically-active perm-selective membranes are presented to illustrate some of the problems encountered with such membranes. The use of non-perm-selective wall-and-tube reactors is then considered. Finally, the results of model calculations are presented which show that the most promising confirmation for the use of perm-selective membranes is one in which the membrane and catalyst are in separate units and external recirculation of reactants and products is carried out.

The use of membrane reactors for catalytic n-butane oxidation to maleic anhydride with a butane-rich feed

Abstract Selective oxidation of n -butane to maleic anhydride was studied using a tubular ceramic membrane reactor loaded with a commercial VPO catalyst and under both O 2 -rich and butane-rich feed conditions. The study was carried out using a configuration by which butane was fed to the inner tube (tube-side) where the catalyst was mounted and O 2 was fed either entirely to the outer tube (shell-side) or distributed in a certain ratio between the tube- and shell-sides with a variation of the pressure difference across the membrane, Δ P . It was observed that the use of a butane-rich feed under this configuration gives a higher maleic anhydride yield and that both Δ P values and the way feed O 2 was distributed can have a significant effect on the reaction rate.

A study of Pt/ZrO2 catalysts for water-gas shift reaction in the presence of H2S

Publisher Summary This chapter presents the results of an investigation of the interaction of Pt/ZrO 2 with H 2 S and of the effect of sulphur on the activity of the catalyst in the water-gas shift reaction (WGSR). The chapter also describes results that show that it is possible to modify the catalyst to make it more sulphur resistant. Pt/ZrO 2 catalyst has higher WGS activity in the presence of H 2 S compared to Fe–Cr, Cu–Zn and Co–Cr catalysts under the same conditions. H 2 S reacts preferentially with Pt giving H 2 and PtS blocking the surface Pt sites. ZrO 2 does not react with nor adsorb H 2 S at temperatures above 300˚C.The modification of Pt/ZrO 2 with C1 - leads to a reduction of S-uptake by the catalyst and improved its WGS activity in the presence of H 2 S; the addition of K + to Pt/ZrO 2 catalyst has the opposite effect.

A modified robotic system for catalyst preparation by wet or dry impregnation

A modified robotic workstation has been developed which is able to reproduce a conventional catalyst preparation method used routinely in our laboratory, thereby increasing significantly the number of catalysts that can be prepared at once. This paper describes some of the features of this modified system and outlines some of the difficulties encountered in transferring from manual to automatic operation. Some catalytic test results are given for the selective oxidation of propane over a catalyst consisting of Mo-V-Nb-W oxides supported on alumina which illustrate good reproducibility of data for samples prepared with the robotic system and a close similarity with data obtained with equivalent manually prepared materials.