Domenico Pisano

Catalysts for the Intensification of the Water Gas Shift Process

Nowadays the Water Gas Shift process (WGS) is performed in two stages, a first step at high temperature (HTS), carried out at 623–873 K, and a low temperature step (LTS) at 423–573 K, to reach a favorable thermodynamic equilibrium condition. This kind of configuration is expensive and requires complex operative conditions, so to make preferable process intensification. This could be achieved through the development of new structured catalytic formulations, characterized by enhanced thermal transfer properties, able to improve the heat distribution along the catalytic bed. For this purpose the most promising catalytic systems are precious metal based supported on open cells metallic foam carriers. In this paper we report a preliminary study on the preparation and the evaluation of differently-supported Pt-based catalysts, as promising precursors in the preparation of structured catalysts for the process intensification of WGS reaction.

Comparative studies of low temperature water gas shift reaction over platinum based catalysts

Water gas shift reaction (WGS) is normally performed in a two-stage process, a first stage at high temperature (HTS) conventionally carried out at 623 873 K on Fe/Cr-based catalyst, to take advantage from a fast reaction, and a second stage at low temperature (LTS) at 423 573 K on Cu/Zn-based catalysts, to reach a favourable thermodynamic equilibrium condition. A single-stage process involves at the same time a cost reduction in plant setup as well as operative conditions; however at the moment, due to the lack of efficient catalytic systems the one-stage WGS systems is not widely diffused. Noble metals arise today as a promising solution in this direction, so in this work great attention was focused on the preparation and testing of differently-supported Platinum-based catalysts.

High Thermal Conductivity Structured Carriers for Catalytic Processes Intensification

Process intensification is conceived as a way to optimize fixed and operating costs in an industrial plant. It is not only related to a reduction of the size of equipments, but also to the change of the production method, by enhancing both chemical that physical aspects of the process. In particular, when there has to deal with exothermic equilibrium reactions, such as the Water Gas Shift, the main problem is that the conversion is limited by the kinetics at the inlet of a catalyst bed, because temperature is low, and is thermodynamically limited at the outlet, because in the adiabatic reactor temperature raises, lowering the equilibrium value. A good solution would be the use of a high conductive carrier, able to redistribute the heat of reaction along the catalyst bed. The aim of this work was to study the heat transfer phenomenon on structured carriers such as open cell foams, by estimating also the thermal properties by a mathematical model elaborated for the heat transfer system.

Catalytic Activities of Bimetallic Catalysts for Low Temperature Water Gas Shift Reaction

A comparative study on the activity of bimetallic Pt/M/CeZrO4(M=Na,Mo,Sn,Cu,Zn) catalysts is presented. The catalysts were prepared by wet impregnation method, by loading separately the two metals, with a Pt/M molar ration of 1. All the catalysts were fully characterized by several physical-chemical analytical techniques (EDXRF, XRD, B.E.T., H2-TPR) and the performance compared with the corresponding monometallic Pt/CeZrO4derivate. The 1Pt/1Sn/CeZrO4and 1Pt/1Na/CeZrO4catalysts showed a similar CO conversion to that of the monometallic Pt-based catalyst in the temperature range of 473675 K, however a reduced occurrence ofmethanation, allows a higher production of hydrogen with the bimetallic systems.