Patent GB-708832-A (GB)
Title: Process for the production of endothermic gas reaction products
IPC: C10G9/26
Filed: 1951-07-23
Abstract: <PICT:0708832/IV (b)/1> In a process for converting natural gas or other hydrocarbons to more unsaturated hydrocarbons, e.g. containing acetylene, olefins or aromatics, by partial combustion and cracking, "make" and heating stages are alternated with reversal of gas flow through two refractory masses 2, 3 and an intervening free space 8. To start up, the furnace is preheated by combustion as of liquid or gaseous fuel in chamber 8 and withdrawal of combustion products downwardly through the flues 4 of both masses, spaced 6, 7, and an outlet line 53.  Temperatures of preferably 1100-1300 DEG  C. at the top and 100 DEG  C. of the masses are obtained.  A make stage of one minute's duration is then started by introduction of a 3 : 2 mixture of propane &c. and air from a mixer 16 through a line 10. As it reaches the top of refractory 2 it becomes inflammable; about 10-20 per cent of the propane is burnt and the balance cracked, the reactions being completed in chamber 8.  Heat is imparted to refractory 3 as the gases descend to an outlet line 11 leading to purification plant.  The heating stage also of one-minute is initiated by reversing valves 14, 29, in lines 10, 11, so as to admit a fuel gas-air mixture to refractory 3 for combustion which is completed in chamber 8, the hot products heating refractory 2 on their way to outlet line 53.  A pump P may be employed in the make stage to produce sub-atmospheric conditions as for generating acetylene, or to obtain higher olefins from higher molecular weight material, pressures as from 2-5 atmospheres may be employed.  In one example, a gas obtained from propane comprises ethylene 22.7, hydrogen 18.9, methane 12.1, propane 11.1, propylene 6.0, carbon monoxide 4.5, acetylene 2.5, carbon dioxide 1.0 and nitrogen 21.2 per cent.  In another, in which natural gas, mainly methane, is mixed with air in the ratio 9 : 11 and the make stage is effected at 1/2 atmospheric pressure, a gas consisting of hydrogen 46.8, acetylene 8.6, carbon monoxide 5.4, methene 4.4, carbon dioxide 1.1, ethylene 0.7 and nitrogen 33.0 per cent is obtained.  Specifications 697,108, [Group XIII], and 705,393 are referred to.ALSO:<PICT:0708832/III/1> In a process for converting ammonia into hydrazine by partial p combustion "make" and heating stages are alternated with reversal of gas flow through two refractory masses 2, 3 and an intervening free space 8.  To start up the furnace is preheated by combustion as of liquid or gaseous fuel in chamber 8 and withdrawal of combustion products downwardly through the flues 4 of both masses, spaces 6, 7 and an outlet line 53.  Temperatures of preferably 1100 DEG -1300 DEG C. at the top and 100 DEG C. of the masses are obtained.  In an example, a make stage of one minute's duration is started by introduction of a 3 : 2 mixture of the starting material and air from a mixer 16 through a line 10.  As it reaches the top of refractory 2 it becomes inflammable; about 10-20 per cent. is burnt and the balance cracked the reactions being completed in chamber 8.  Heat is imparted to refractory 3 as the bases descend to an outlet line 11 leading to purification plant.  The heating stage also of one minute is initiated by reversing valves 14, 29, in lines 10, 11, so as to admit a fuel gas-air mixture to refractory 3 for combustion which is completed in chamber 8, the hot products heating refractory 2 on their way to outlet line 53.  A pump P may be employed in the make stage to produce sub-atmospheric conditions.  Specifications 697,108, [Group XIII], and 705,393, are referred to.