GB854268A - The electrothermic production of hydrogen cyanide by fluidized bed techniques - Google Patents

Abstract

Hydrogen cyanide is produced by passing upwardly a gas comprising ammonia through a bed of electrically conductive particles so as to maintain the bed in a fluidised state and passing an electric current through the bed to heat it sufficiently, e.g. to 1300 DEG -1600 DEG C. to form hydrogen cyanide, which is recovered from the outgoing gases. The particles may be carbon, preferably calcined fluid petroleum coke produced in a p fluidised bed petroleum cracking process of metallurgical coke or stoker coke. The ingoing gas may be ammonia alone or mixed with a hydrocarbon gas and may contain 1/2 -2% of carbon disulphide as a catalyst. The ratio of moles of ammonia to atoms of carbon in the hydrocarbon gas is greater than 1:1. When propane is used the volume ratio of ammonia to propane is between 3:1 and 5:1. When methane is used the volume ratio of ammonia to methane is between 1:1 and 5:3. Ethane, butane, ethylene, propylene, natural gas or higher hydrocarbons may be used. The contact time of the gas with the bed is normally less than one second, e.g. 0.1-0.5 seconds. Two parallel graphite electrodes may be immersed in the coke, or a single axial electrode is used with the wall of the container as the other electrode. D.C. or A.C. is supplied and the formation of open arcs between the electrodes is avoided. The gas passes up into the bed through a carbon diffusion disk into the bed in a glass vessel the rate of supply being diminished once the bed is fluidised and hot. A thermocouple is placed in a well in the bed.