GB843663A - Apparatus for indirectly heating gaseous, liquid or solid media - Google Patents

Abstract

843,663. Flameless combustion. METALLGESELLSCHAFT A. G. Sept. 27, 1957 [Sept. 29, 1956; Sept. 10, 1957], No. 30414/57. Class 75(1) [Also in Group XIII] Apparatus for indirectly heating gaseous or liquid media comprises at least one heatexchanger and two or more catalyst units each containing a sulphur-resistant hydrogenation catalyst, a mixture of combustible gas and oxygen or oxygen-rich gas at 200-280‹C being admitted in turn to each catalyst unit for flameless combustion, the composition of the mixture being regulated at each unit to obtain a desired post-combustion temperature for heating the heat-exchanger. The products are used to heat a medium to be treated such as in the catalytic hydrogenation of coal and tar, hydro-refining of benzine, oil, or benzole, synthesis of methanol, ammonia, re-forming of benzine into aromatics, or for re-heating turbine gases. To the hot combustion products thus cooled by their heating the medium to be treated there is added further air or combustible gas for similar sequential catalytic combustion to raise the temperature to 450-800‹C for further heating of the medium to be treated. The sequence is repeated and the final catalytic combustion products are used to pre-heat the freshly entering combustible-containing and oxygen-containing gases to the ignition temperature 200-280‹C. before entry into the first catalyst body. At starting the initial heating to ignition temperature may be electrically effected by the entering combustible gas at 1 being temporarily diverted to heater 18, Fig. 1, from its normal passage through the heater 2 which is heated by the finally exhausted combustion products from line 19. The combustible gas now heated to ignition temperature has an appropriate amount of air added from the line 5 before passing to the sulphur-resistant catalyst in chamber 4 where catalytic combustion to 450-800‹C is effected, the combustion-product gases passing by line 6 to a cylinder 8 fitted with baffles whereby the gases flow in zig-zag manner across tubes 7 carrying the medium to be heated. The combustionproduct gases now cooled to the ignition temperature then pass by line 9 to receive a further appropriate supply of air from line 11 for further combustion by the catalyst in chamber 10 and then pass to a further baffled heating cylinder with tubes 14 carrying the medium to be heated. Fig. 6 shows a columnar arrangement of catalyst chambers connected for serial combustion by connections 55 ... 58 to a separate drum 61 sectionalized by partitions 63 and provided with baffles 74 to direct the combustion gases across the tubes 66 to which the medium to be heated is supplied through end cover 69 and discharged through end cover 70. Fig. 12 shows a horizontal drum carrying the tubes for the medium to be heated, the end covers being chambered to give out and return flows in different banks of tubes ; the drum is sectionalized by partitions 218, 219, 220 and carries on its underside catalyst chambers 202 ... 205 with the initial combustible gas and appropriate supply of air being supplied to catalyst chamber 202 at inlets 241, 252 and the combustion product gas then passing to drum section 214 to be baffled across the tubes 207 ... 210 and pass to the top of the next catalyst chamber 203 where a further appropriate supply of air is admitted at 238. Similar actions take place in subsequent sections of the drum and in subsequent catalyst chambers. To permit withdrawal of the tube assembly from the drum the sectionalizing partitions 218 ... 220 are not welded to the drum but are provided, Fig. 15, with bimetallic sealing rings 280/381 which during operation expand into sealing engagement with the drum wall 201. Alternatively a wedge-expanded split ring may be used, Figs. 13, 14 (not shown). For the combustible gases there may be used the residual or tail gases of the hydrogenation or synthesis treatment of the materials forming the medium to be heated. The various tubes. may be provided with corrugated expansion joints. Catalysts used are platinum metal or the oxide, sulphur and phosphorus compounds of the platinum and palladium group applied on carrier material, or a cobalt-molybdenum solution impregnated on a carrier material such as aluminium oxide, silica, or corundum.