GB380893A - Process for the manufacture of carbon and hydrogen - Google Patents

Abstract

In the catalytic decomposition of gaseous hydrocarbons or of gases containing hydrocarbons to form carbon black and hydrogen, the process of the parent Specification is modified by commencing the reaction with undiluted catalyst and passing the hydrocarbon gas thereover, the carbon formed penetrating the catalyst and becoming a carrier therefor. After a time, a concentration of catalyst in the total of catalyst and carbon black is reached at which the reaction proceeds most efficiently and this concentration is maintained by the continuous or intermittent addition of fresh catalyst. In the case of iron and methane, the favourable concentration is 80 to 45 per cent and the gas is passed until the volume of gases evolved reaches a maximum and when this begins to decrease fresh catalyst is added e.g. as carbonyl or as a solid, such as iron, previously activated by high temperature treatment with a hydrocarbon or carbon monoxide and thus containing 15-20 per cent of carbon. In operation, the gas to be decomposed is preferably first passed over a less efficient catalyst, e.g. one largely diluted with carbon black, and then over a catalyst maintained at the desired concentration. The gas may be passed through the first chamber until reaction ceases after which the catalyst may be removed by known methods. In addition to iron powder, iron oxide or carbonate, or mixtures of iron and nickel, iron and zinc, cobalt and nickel, or iron, nickel and zinc may be employed as catalysts, and an activator such as an alkaline earth oxide may be added.