GB753975A - A process for the purification of tar-containing gases - Google Patents

Abstract

753,975. Purifying gases. OTTO & CO. GES., DR. C. KO-WE NIEDERSCHACHTOFEN GES., and FUCHS, W. Oct. 12, 1954 [Oct. 16, 1953], No. 29348/54. Class 55(2). In a process for purifying tar-containing gases, the gas containing tar in vapour or mist form is brought into contact with a non- metallic multi-substance catalyst which promotes the decomposition at comparatively low temperatures, e.g. 600‹-700‹C., of the tar into permanent gases, any non-gaseous tarry substances remaining in the gas are subsequently removed by cooling and/or washing the gas. A suitable catalyst consists of a mixture of a carbon-containing substance, e.g. coke, and a clay containing substance, e.g. montmirollonite, e.g. the coke being provided with a coating of the montmirollonite. High boiling point constitutents of the tar are converted into lower boiling point tar oils which are recovered by the cooling and/or washing step. In the event that the gases contain substantial amounts of high boiling point constituents the gas may require a second treatment consisting of passing the gas from the first treatment through or over a metallic catalyst whereby the residual high boiling point constituents are converted into low boiling point products. The catalyst may in this second treatment be in the form of a fixed or a vortex bed or the catalyst may be added in a finely divided state to the gas to be treated and subsequently separated therefrom by mechanical means.