Control of Sulfur Emissions

Sources of atmospheric sulfur emissions from the process industries are  

Before considering treatment of sulfur emissions to atmosphere, their minimization at source should be considered. Sulfur emissions can be minimized at source through  

Sulfur emissions from combustion processes can be reduced by switching to a fuel with lower sulfur. The sulfur content of fuels varies significantly. Generally, the sulfur content is gas liquid solid. This order arises mainly from the relative ease with which the fuels can be desulfurized. Desulfurizing coal prior to combustion is extremely difficult. It must be first ground to very fine particles (of the order of 100 xm) to liberate the mineral (inorganic) sulfur. The light coal can then be 

Removal of sulfur from gas streams is generally removal of H2S or removal of S02n. Generally, removal of the sulfur in the form of H2S is much more straightforward than in the form of S02. H2S can be removed by absorption, as already discussed. Chemical absorption using amines is the most commonly used method. However, other solvents can be used for chemical absorption, for example, potassium carbonate. Physical absorption is also possible using solvents such as propylene carbonate and methanol. 

So far, the techniques to recover sulfur have all related to sulfur in the form of H2S. Consider now how sulfur in the form of S02 can be dealt with. Sulfur dioxide can be reacted with limestone to produce solid calcium sulfate (gypsum), according to the equations11  

---

In addition, the electron microprobe data indicated an unusual but noticeable build up of calcium associated with the organic matter of the desulfurized coal. This increase in calcium may have implications for subsequent control of sulfur emission during the combustion of the desulfurized coal. It was also shown that extractions with cold nitric acid can be affected by changes in the mineral matter content caused by the chemical... 

VijTThen control of sulfur emission became an urgent concern of refin-eries and other plants operating on hydrocarbon feeds, a host of processes were developed on paper (I). The past 2 yrs have seen a shakedown and thinning of these processes. Of the more than 60 originally proposed, only about half a dozen have been developed commercially. This paper concerns itself with two of those commercially proved processes developed by the French Petroleum Institute (2, 3) one for taking emissions down to about 1500 ppm sulfur dioxide after incineration and the other for reducing sulfur dioxide to one tenth that level. At this time 19 IFP-1500 plants are licensed as are four of the IFP-150 plants. 

---