Sulfide process flow

The Claus process consists of partial combustion of the hydrogen sulfide-rich gas stream (with one-third the stoichiometric quantity of air) and then reacting the resulting sulfur dioxide and unbumed hydrogen sulfide in the presence of a bauxite catalyst to produce elemental sulfur. Refer to the process flow diagram in Figure 7. 

By running liquid water countercurrent to recycled gaseous hydrogen sulfide through first a cold tower and then a hot tower, as shown schematically in Fig. 12.6, water enriched in deuterium may be withdrawn from the water leaving the cold tower. The principle of the process and process flow sheets are described in detail in Chap. 13. 

A simplified process flow diagram is given in Figure 9-11 (Krupp Wilputte, 1988). The crude gas, which contains hydrogen sulfide, hydrogen cyanide, and ammonia, is first passed through a cooler (not shown) in which the temperature and ammonia content are adjusted by direct contact with water. Prom there the gas flows to the contactor in which it is washed countercurrently with the Perox solution and practically all of the H2S and HCN are absorbed and converted to (NH4)2S and NH4CN. 

Originally, vulcanization implied heating natural rubber with sulfur, but the term is now also employed for curing polymers. When sulfur is employed, sulfide and disulfide cross-links form between polymer chains. This provides sufficient rigidity to prevent plastic flow. Plastic flow is a process in which coiled polymers slip past each other under an external deforming force when the force is released, the polymer chains do not completely return to their original positions. 

Fig. 5. Flow sheet foi Sheiiitt-Goidon process for production of nickel and cobalt metals from sulfide ore.

Chevron s WWT (wastewater treatment) process treats refinery sour water for reuse, producing ammonia and hydrogen sulfide [7783-06-04] as by-products (100). Degassed sour water is fed to the first of two strippers. Here hydrogen sulfide is stripped overhead while water and ammonia flow out the column bottoms. The bottoms from the first stripper is fed to the second stripper which produces ammonia as the overhead product. The gaseous ammonia is next treated for hydrogen sulfide and water removal, compressed, and further purified. Ammonia recovery options include anhydrous Hquid ammonia, aqueous Hquid ammonia, and ammonia vapor for incineration. There are more than 20 reported units in operation, the aimual production of ammonia from this process is about 200,000 t. 

In a modem carbon disulfide plant, all operations are continuous and under automatic control. On-stream times in excess of 90% are obtainable. The process is in three steps melting and purification of sulfur production and purification of carbon disulfide and recovery of sulfur from by-product hydrogen sulfide. A typical process appears in the flow diagram of Figure 1 (50). 

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