Oxidative decomposition of o-dichlorobenzene over V2O5/TiO2 catalyst washcoated onto wire-mesh honeycombs

Abstract

A novel wire-mesh (WM) honeycomb reactor was developed and tested for the oxidative decomposition of 1,2-dichlorobenzene (o-DCB) in air over V2O5/TiO2 catalyst. The WM-honeycomb substrate had triangle-shaped channels and was fabricated from flat and corrugated carbon steel wire-meshes (20 Taylor mesh). The geometric surface area of the substrate is similar to that of a ceramic honeycomb module with square channels of size 3 mm. The optimal loading of powder catalyst on the WM-honeycomb module was determined experimentally. This loading was adopted thereafter in experiments probing the effect of changes in the working conditions. The influences of temperature, flow rate and o-DCB concentration on the conversion of o-DCB by the reactor were investigated. Results were compared with those for similar wash-coated ceramic honeycomb modules. WM-honeycombs were characterized by much higher conversion than ceramic honeycomb modules, which can be attributed to radial mixing across the mesh screen pores. The performance gap between the two types of reactor was enhanced on going to higher values of the o-DCB concentration, flow rate or temperature, or in circumstances where external mass transfer or radial mixing was important to the overall reaction rate. The stability of both honeycomb reactors was examined by running them for 50 h at 900 ppm, 3000 cm(3)/min and 270degreesC. The WM-honeycomb module showed only small fluctuations in the conversion over the course of the run and good reproducibility. The WM-honeycomb exhibits higher efficiency and much lower cost than the ceramic honeycomb, so the WM-honeycomb is a promising option for use in a variety of industrial applications. (C) 2002 Elsevier Science B.V. All rights reserved.