Improvements in the production of hydrogen, carbon monoxide/hydrogen mixtures of nitrogen/hydrogen mixtures

摘要

In the production of hydrogen, alone or mixed with carbon monoxide or nitrogen, partial combustion of gaseous hydrocarbons or gases containing the same is effected with such an amount of oxygen or air that no deposition of carbon occurs during combustion and the gaseous products are passed over solid carbonaceous matter, e.g. coke, at a high temperature, e.g. 1200 DEG C., the heat generated in the combustion stage being such that no blowing period is required to maintain the temperature of the coke. Steam may be added either before or after the primary combustion stage. When dealing with a gas mixture containing 60 per cent of methane, not less than 40 per cent of oxygen must be supplied; more oxygen, however, is preferably employed, e.g. equal volumes of the two gases. In the case of ethane, more than one volume of oxygen to one of ethane is used, preferably up to two volumes of oxygen to one of ethane. In practice, a coke bed is provided at one end of the combustion chamber and oxygen, or air, and the hydrocarbon gas are separately preheated, the p temperature of the hydrocarbon gas being such that carbon is not deposited. In the case of methane, 900 DEG C. should not be exceeded, and the preheater should be constructed from materials inimical to the production of carbon, e.g. austenitic alloy steels or silica. The oxygen or air may be heated to as high a temperature as possible. The final gas mixture may be catalyzed with steam to convert the carbon monoxide to dioxide which is removed, leaving a mixture of nitrogen and hydrogen. If pure hydrogen be required, the monoxide and nitrogen may be removed by low temperature treatment. Steam used in the process may be obtained from the heat of the gases after the preheating stage, or by spraying water into the hot gases after leaving the coke bed. An example dealing with methane is furnished and Specifications 29367/10, [Class 55 (i), Coking &c.], and 247,176, [Class 90, Non-metallic elements], are referred to.