Sulfur, emission

Calcium carbide has been used in steel production to lower sulfur emissions when coke with high sulfur content is used. The principal use of carbide remains hydrolysis for acetylene (C2H2) production. Acetylene is widely used as a welding gas, and is also a versatile intermediate for the synthesis of many organic chemicals. Approximately 450,000 t of acetylene were used aimuaHy in the early 1960s for the production of such chemicals as acrylonitrile, acrylates, chlorinated solvents, chloroprene, vinyl acetate, and vinyl chloride. Since then, petroleum-derived olefins have replaced acetylene in these uses. 

The lignitic coals of the northern United States tend to have low sulfur contents, making them attractive for boilet fuels to meet sulfur-emission standards. However, low sulfur content coals have impaired the performance of electrostatic precipitators. The ash of these coals tends to be high in alkaline earths (Ca, Mg) and alkaUes (Na, K). As a result, the ash can trap sulfur as sulfites and sulfates (see Airpollution control methods). 

Air Pollution. Particulates and sulfur dioxide emissions from commercial oil shale operations would require proper control technology. Compliance monitoring carried out at the Unocal Parachute Creek Project for respirable particulates, oxides of nitrogen, and sulfur dioxide from 1986 to 1990 indicate a +99% reduction in sulfur emissions at the retort and shale oil upgrading faciUties. No violations for unauthorized air emissions were issued by the U.S. Environmental Protection Agency during this time (62). 

The additional sulfur for polysulfide pulping can upset the sodium—sulfur balance in the kraft recovery cycle and increase sulfur emission problems. In the MOXY (Mead Corp.) process, polysulfide is formed from kraft white Hquor by catalytic oxidation of sodium sulfide in the white Hquor using air. 

R. S. Saltzman, Challenges in Stack Sulfur Emissions Measurements, paper presented at 30th Annual Petroleum Mechanical Engineering Conference, Tulsa, OHa., Sept. 21-25,1975. 

A bleed from the scmbbing system is sent to a sour slurry stripper. The water is then clarified and can be recycled to minimize the volume of effluent to be biotreated and discharged or evaporated. The acid gas from the acid gas removal system and from the sour slurry stripper is fed to a Claus plant, where salable elemental sulfur (qv) is produced. For maximum sulfur recovery and minimal sulfur emissions, the Shell Claus off-gas treating process (SCOT) is used. 

Sulfur Emissions Sulfur present in a fuel is released as SO9, a... 

Proposal for a council directive on the use of fuel oils, with the aim of decreasing sulfurous emissions. Official journal 19, C-54 (March 1976). 

Ethene and propene are produced as bulk feedstocks for the chemical (polymer) industry and therefore their purities are important parameters. In particular, H2S and COS are compounds which may not only cause corrosion problems in processing equipment, but also may have detrimental effects on the catalysts in use. Eurthermore, air pollution regulations issued by, among others, the US Environmental Protection Agency (EPA) require that most of the sulfur gases should be removed in order to minimize Sulfur emissions into the atmosphere. Therefore, these compounds have to be determined to the ppb level. 

The sign on technology (T) and environmental policy (Ej,) are uncertain and depend on the particular technology and policy. For example, eiivironmeti-tal regulations requiring lower sulfur emissions favor gas over coal, while new technologies that make oil cheaper to use increase oil demand at the expense ot gas and coal. 

For example, sulfur emissions from utility power plants in the United States are subject to an emissions cap and an allowance-trading system established under the Clean Air Act. An effective cap on annual sulfur dioxide emissions took effect in 2000, so no more than 8.95 million tons of SO can be emitted annually. Utilities that want to build another coal plant must purchase sulfur emission allowances from others who do not need them. This system provides a market incentive for utilities to reduce their sulfur emissions as long as the cost of such reductions is less than the price of purchasing the allowances. 

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... 

Atmospheric sulfur emissions can be minimized at source by improving the process yields and desulfurization of fuels prior to combustion. The difficulty of fuel desulfurization is solid > liquid > gas. Sulfur can be removed from emissions either as S02 or H2S. Removal of the H2S can be by ... 

Non-saline water samples are normally acidified to stabilise them during storage. There is an effect due to hydrochloric acid concentration on the sulfur emission signal. This effect is conveniently overcome by making the acid content of samples and standards identical at, for example, 1 vol%. 

The chemiluminescent reaction with chlorine dioxide provides a highly sensitive and highly selective method for only two sulfur compounds, hydrogen sulfide and methane thiol [81]. As in the flame photometric detector (FPD), discussed below, atomic sulfur emission, S2(B3S -> ) is monitored in the wave-... 

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