Patent GB-725327-A (GB)
Title: Improvements in or relating to regenerative processes and apparatus for endothermically and exothermically altering gaseous materials
IPC: B01J8/02
Filed: 1953-02-27
Abstract: <PICT:0725327/IV (b)/1> A process for effecting endothermic gaseous reactions comprises preheating a gas by passage through straight channels in a heat regenerative mass progressively hotter in the direction of flow, effecting a partial combustion and endothermic alternation in a reaction zone and quenching the products by passing through the straight channels of a second regenerative mass progressively cooler in the direction of flow, heat being imparted for the process by an exothermic reaction in part, at least, simultaneously with the endothermic reaction and with reactants separately preheated, one at least by passage through one of the regenerative masses, the gas flow being periodically reversed throughout the process.  The production of olefines and acetylenes, synthesis gases for alcohol synthesis, aromatic hydrocarbons from paraffinic hydrocarbons, dehydrogenation and isomerization products, dehydration products from alcohols, cracked low molecular weight hydrocarbons are referred to.  In one embodiment natural gas, &c. or petroleum hydrocarbons containing ethane, propane, butane, olefins, &c. are passed with or without steam or other diluent from line 29 through valves 30, 33 into and through the straight flues of a regenerative mass 3 and air &c. from a line 34 traverses a similar mass 4 after a preheating operation in which fresh gas introduced through burners 19, 20 is burnt alternately in chambers 7, 8, the hot products passing through Venturis 9, 10 to a reaction chamber 15 which may contain catalyst and thence out through regenerative masses 5, 6, and 3, 4, so that chamber 15 is at 900 DEG -1300 DEG  C. and the inner ends of the masses at the same or somewhat lower temperature and their outer ends at about 75 DEG -300 DEG  C.  The operating steps in which the reactants are alternately introduced into masses 3, 4, and 5, 6 for periods of 1-3 minutes, effect a mixing of the gases during passage through chamber 7, Venturies 9, chamber 11 and a section 13 containing metal grids &c. or checkers, e.g. like the regenerative masses, or in the reverse flow chamber 8, Venturis 10, chamber 12 and section 14.  Partial combustion is completed in chamber 15, 15-40 per cent of the hydrocarbons being burnt and the rest cracked, the product gases finally passing through a valve 39 and outlet pipe 44 to a purification or storage system. A 4-stage cycle may comprise stages in which the routes of the fuel and air &c. through the regenerative masses are interchanged so that any carbon deposited on the checkers may be burnt off and inequalities in temperatures balanced.  A product gas including 36 per cent hydrogen, 15.4 carbon monoxide, 6 methane and 39.8 per cent nitrogen is obtained from natural gas and air in a 1 : 2 ratio.  A pump may be inserted in the outflow line and subatmospheric pressures, as for acetylene and hydrazine production, employed.  In a modification a part only of the necessary heat may be supplied by combustion simultaneously with the endothermic alteration, the rest being provided by an alternating heating stop in which fuel is burnt in the reaction chamber.  Another form of apparatus comprises two pairs of regenerative masses on each side of a partition extending some distance in the form of an inverted U, or two masses only may be employed, one of the reactants being preheated by other means. Specifications 697,108, [Group XIII], and 705,393 are referred to.ALSO:<PICT:0725327/III/1> A process for effecting endothermic gaseous reactions comprises preheating a gas by passage through straight channels in a heat regenerative mass progressively hotter in the direction of flow, effecting a partial combustion and endothermic alteration in a reaction zone and quenching the products by passing through the straight channels of a second regenerative mass progressively cooler in the direction of flow, heat being imparted for the process by an exothermic reaction in part, at least, simultaneously with the endothermic reaction and with reactants separately preheated, one at least by passage through one of the regenerative masses, the gas flow being periodically reversed throughout the process.  The production of carbon black, of hydrazine from ammonia, sulphur from sulphur dioxide, air and natural gas, hydrogen and Fischer-Tropsch and ammonia synthesis gases from hydrocarbons, steam and air or carbon dioxide, nitric oxide from air, hydrogen cyanide from hydrocarbons and ammonia is referred to.  In one embodiment, natural gas, &c. or petroleum hydrocarbons containing ethane, propane, butane, olefins &c. are passed with or without steam or other diluent from line 29 through valves 30, 33 into and through the straight flues of a regenerative mass 3 and air &c. from a line 34 traverses a similar mass 4 after a preheating operation in which fresh gas introduced through burners 19, 20 is burnt alternately in chambers 7, 8 the hot products passing through venturis 9, 10 to a reaction chamber 15 which may contain catalyst and thence out through regenerative masses 5, 6 and 3, 4 so that chamber 15 is at 900 DEG -1,300 DEG  C., and the inner ends of the masses at the same or somewhat lower temperature and their outer ends at about 75 DEG -300 DEG  C.  The operating steps in which the reactants are alternately introduced into masses 3, 4 and 5, 6 for periods of 1-3 minutes effect a mixing of the gases during passage through chamber 7, venturis 9, chamber 11 and a section 13 containing metal grids &c. or checkers, e.g. like the regenerative masses, or in the reverse flow, chamber 8, venturis 10, chamber 12 and section 14.  Partial combustion is completed in chamber 15, 15-40 per cent. of the hydrocarbons being burnt and the rest cracked, the product gases finally passing through a valve 39 and outlet pipe 44 to a purification or storage system.  A 4-stage cycle may comprise stages in which the routes of the fuel and air &c. through the regenerative masses are interchanged so that any carbon deposited on the checkers may be burnt off and inequalities in temperatures balanced.  A product gas including 36 per cent. hydrogen, 15.4 carbon monoxide, 6 methane and 39.8 nitrogen is obtained from natural gas and air in a 1:2 ratio.  A pump may be inserted in the outflow line and sub-atmospheric pressures, as for acetylene and hydrazine production, employed.  In a modification, a part only of the necessary heat may be supplied by combustion simultaneously with the endothermic alteration, the rest being provided by an alternating heating step in which fuel is burnt in the reaction chamber.  Another form of apparatus comprises two pairs of regenerative masses on each side of a partition extending some distance into a superposed reaction chamber and providing a through gas passage in the form of an inverted U, or two masses only may be employed, one of the reactants being preheated by other means.  Specifications 697,108, [Group XIII]; and 705,393 are referred to.