GB357178A - Improvements in the production of sulphur from sulphur dioxide - Google Patents

Abstract

<PICT:0357178/III/1> In the production of sulphur from sulphur dioxide by reduction with carbon at a high temperature, low-temperature coke (semi-coke) is used as the reducing agent, the result being that a lower reaction temperature of 600-800 DEG C. is rendered feasible or, if a higher reaction temperature of 1000 DEG C. is employed, the output is increased. The heat of the reduced gases may be used to produce further quantities of semi-coke, any deleterious action on the sulphur of the tarry vapours so produced being avoided by passing the gases through a bed of highly heated coke substantially free from volatile matter. Reduction may be effected by passing the gas to be reduced through a bed of lump semi-coke heated externally, by the alternate passage of air and gas through the coke or a mixture of the gas and air may be passed through the coke. Alternatively, granular or pulverized semi-coke may be employed, the gas being so forced through as to produce turbulence, or the coke may be dispersed in the gas and the mixture heated. As shown, two vertical retorts D, D<1> communicating at the top are charged with semi-coke from the top, a charge of coal being placed above this in each retort. Both retorts are raised to say 1000 DEG C. by air admitted through ports B, C, A mixture of air and gas containing sulphur chloride is then blown through the port B, the resultant gases passing through both layers of coal and the other layer of coke and out at the port C, so much air being employed as will render the reaction in the first bed exothermic. Both layers of coal are thereby converted to semi-coke and the tarry vapours produced are absorbed in the second layer of coke, the passage of gas being reversed after the temperature of this layer has fallen to say 800 DEG C.; an example is furnished in connection with this form of apparatus. In a second example, only one column of semi-coke covered by coal is employed the gases and tarry vapours being carried direct to a retort containing high-temperature coke maintained at a temperature of 1100-1200 DEG C. by preheated secondary air. Sulphur may be separated from the gases by the methods described in Specifications 354,207 and 355,832.