GB493929A - An improved process for making carbon black, which is poor in impurities, and hydrogen or hydrogen-containing gases - Google Patents

Abstract

In the manufacture of carbon black and hydrogen by the thermal dissociation of hydrocarbons, e.g. waste gases, and particularly hydrocarbons which decompose with the evolution of heat, with or without the addition of a catalyst such as iron pentacarbonyl, the reaction products are cooled immediately after their formation. The cooling may be carried by known cooling devices, e.g. cooling ribs on the exterior of the apparatus, or by liquid cooling, e.g. a steam boiler and may be assisted by narrowing the cross-section of the path which the products traverse thus increasing their velocity and removing them rapidly from the reaction zone; by admixing gases or vapours with the cracked products, e.g. gases of good thermal conductivity such as hydrogen, or of high thermal capacity such as steam, which may be produced in the process. The hydrogen obtained or used in the process may be recirculated for this purpose. The cooling may also be attained by combining the splitting process with heat-consuming processes, e.g. by introducing dissociating gases or vaporizable liquids into the gas stream after the cracking zone. In particular, the process may be applied to the splitting of acetylene or gas mixtures containing it when the gases are supplied to the reaction zone, after ignition, in very large quantities, e.g. more than 10 kg./hour so that no further heat is required. Hydrocarbons such as acetylene, p allylene, dimethyldiacetylene, ethylene, propylene and other olefines, cyclopropane, benzene vapour and dihydrobenzene and mixtures with one another or with exothermic compounds are referred to.