GB953868A - Improvements relating to the purification of gases - Google Patents

Abstract

<PICT:0953868/C3/1> In a process of treating a gas that contains carbon monoxide and sulphur from which the sulphur is absorbed by a circulating absorbent and which is treated for the conversion of CO to CO2, the sulphur in the circulating absorbent is oxidized to SO2 and the heat generated thereby is used in the conversion of CO to CO2 either in forming steam required in the conversion or to preheat the gas or both. Town's gas for example is passed into a heat exchanger 3 to receive heat from purified gas passing therethrough from a pipe 4 and flows into an absorber 6 having fluidized iron oxide at about 400 DEG C., leaving it substantially sulphur-free to enter a cyclone 8, to remove any oxide particles, and then a scrubber 9 to meet hot water supplied via a pipe 10 from a heat exchanger 25, and evaporated to form steam. This flows with the gas into a heat exchanger 12 and then an appliance 15 to convert the CO to CO2 and hydrogen by passing over a catalyst e.g. chromia-promoted iron oxide as a fixed or fluidized bed at 400 DEG to 450 DEG C. Hot water may be sprayed into the gas through a pipe 50 before entering the second of two catalyst beds to control gas temperature and increase the steam in it, the gas leaving to enter the exchangers 12 and 3 (traversed by the incoming gas) and exchangers 18 and 21 (to be cooled by water) and a final pipe 23. Oxide from the absorber 6 flows continuously through a seal 27, which assists in fluidizing it, a pneumatic conveyer 30 and a pipe 32 to a roaster 33 at about 700 DEG to 800 DEG C. to convert the sulphur to SO2, the regenerated oxide being returned to the absorber 6 and the hot gases leaving through cyclone 36, exchanger 25 and a pipe 38 for a sulphuric acid plant. Hot water from the exchangers 3, 12, 18, and a scrubber 9 is drained by pipes 44, 42, 45 and 43 into a main 46 for a tank 47, supplying hot water to the pipes 10 and 50. Burning of additional sulphur in a burner in the roaster 33 will give more heat to the exchanger 25, if desired. Specification 719,056 is referred to.