Methane Pyrolysis for Hydrogen Production: Specific Features of Using Molten Metals

Published data on noncatalytic pyrolysis of natural gas in molten metals are analyzed. The most illustrative results obtained in the past two decades are described. The use of molten metals as reaction medium allows solving the problem of coking of pyrolysis reactors owing to the flotation of the carbon formed to the molten metal surface. The use of liquid metal bubbling reactors allowing the process to be performed at temperatures of up to 1200 degrees C is considered. The maximal conversion was 78% at 1175 degrees C and feeding rate of 50 mL min(-1). The major factors favoring more complete conversion of natural gas in the processes under consideration are elevated temperature, decreased gas bubble size due to the use of bubbling systems of various types, and longer residence time of the gas in the heat carrier due to an increase in the reactor length or to use of various types of packing.