Sulfur oxides sources

Petroleum refineries, along with natural gas processing plants, are probably the best situated sulfur oxides sources with respect to emission control. The availability of hydrogen sulfide allows ready processing of recovered sulfur dioxide to elemental sulfur for disposal. 

Sources Air Quality Criteria for Particulate Matter and Sulfur Oxides, final draft, U.S. Environmental Protection Agency, Research Triangle Park, NC, December 1981 Review of the National Ambient Air Quality Standards for Sulfur Oxides Assessment of Scientific and Technical Information, Draft OAQPS Staff Paper, U.S. Environmental Protection Agency, Research Triangle Park, NC, April 1982. 

EPA, 1981. U.S. EPA, Office of Air Quality Planning and Standards, "Control Technologies for Sulfur Oxide Emission from Stationary Sources," Second Edition, Research Triangle Park, NC, April, 1981. 

Sulfur oxide emissions enter the atmosphere from a variety of sources, some of human origin, others of natural origin. The main sulfur oxide is sulfur dioxide, or SO,. 

Natural gas will continue to be substituted for oil and coal as primary energy source in order to reduce emissions of noxious combustion products particulates (soot), unburned hydrocarbons, dioxins, sulfur and nitrogen oxides (sources of acid rain and snow), and toxic carbon monoxide, as well as carbon dioxide, which is believed to be the chief greenhouse gas responsible for global warming. Policy implemented to curtail carbon emissions based on the perceived threat could dramatically accelerate the switch to natural gas. 

In the USA, the Clean Air Act of 1970 established air-quality standards for six major pollutants particulate matter, sulfur oxides, carbon monoxide, nitrogen oxides, hydrocarbons, and photochemical oxidants. It also set standards for automobile emissions - the major source of carbon monoxide, hydrocarbons, and nitrogen oxides. An overview of the major standards is given in Tab. 10.2. The levels of, for example, the European Union (1996) are easily achieved with the present catalysts. The more challenging standards, up to those for the ultralow emission vehicle, are within reach, but zero-emission will probably only be attainable for a hydrogen-powered vehicle. 

Emissions from sinter plants are generated from raw material handling, windbox exhaust, sinter discharge (associated sinter crushers and hot screens), and from the cooler and cold screen. The primary source of particulate emissions, mainly irons oxides, magnesium oxide, sulfur oxides, carbonaceous compounds, aliphatic hydrocarbons, and chlorides, are due to the windbox exhaust. Contaminants such as fluorides, ammonia, and arsenic may also be present. At the discharge end,... 

Historically, the sulfur oxides have long been known to have a deleterious effect on the atmosphere, and sulfuric acid mist and other sulfate particulate matter are well established as important sources of atmospheric contamination. However, the atmospheric chemistry is probably not as well understood as the gas-phase photoxidation reactions of the nitrogen oxides-hydrocarbon system. The pollutants form originally from the S02 emitted to the air. Just as mobile and stationary combustion sources emit some small quantities of N02 as well as NO, so do they emit some small quantities of S03 when they bum sulfur-containing fuels. Leighton [2] also discusses the oxidation of S02 in polluted atmospheres and an excellent review by Bulfalini [3] has appeared. This section draws heavily from these sources. 

Air emissions from a petroleum distillation unit include emissions from the combustion of fuels in process heaters and boilers, fugitive emissions of volatile constituents in the crude oil and fractions, and emissions from process vents. The primary source of emissions is combustion of fuels in the crude preheat furnace and in boilers that produce steam for process heat and stripping. When operating in an optimum condition and burning cleaner fuels (e.g., natural gas, refinery gas), these heating units create relatively low emissions of sulfur oxides, (SO c), nitrogen oxides (NO c), carbon monoxide (CO), hydrogen sulfide (H2S), particulate... 

The numerous process heaters used in refineries to heat process streams or to generate steam (boilers) for heating or steam stripping can be potential sources of sulfur oxides (SO2, and SO3), nitrogen oxides (NO and NO2), carbon monoxide (CO), particulates, and hydrocarbons emissions. When operating properly and when burning cleaner fuels such as refinery fuel gas, fuel oil, or natural gas, these emissions are relatively low. If, however, combustion is not complete, or heaters are fired with refinery fuel pitch or residuals, emissions can be significant. 

The wavelength-dispersive x-ray spectroscopy method (ASTM D6376) provides a rapid means of measuring metallic elements in coke and provides a guide for determining conformance to material specifications. A benefit of this method is that the sulfur content can also be used to evaluate potential formation of sulfur oxides, a source of atmospheric pollution. This test method specifically determines sodium, aluminum, silicon, sulfur, calcium, titanium, vanadium, manganese, iron, and nickel. 

Fuel cells have several important benefits over conventional electrical eneigy generation from sources such as coal, as they are more efficient at converting fuel sources to end-use energy. The fuel cell vehicle will have no harmful emissions such as nitrogen oxide (NO ), sulfur oxide (SOJ, or particulates. Fuel cells provide waste heat utilization in co-generation, units which serve to raise the overall energy efficiency (65-85%). 

A typical source (see Figure 6-2) consists of an ultraviolet mercury lamp that irradiates a quartz tube through which clean air flows at 5-10 liters/min. A small amount of the oxygen in air is converted to ozone by photolysis. It is important that the incoming air be free of moisture, nitrogen oxides, sulfur oxides, hydrocarbons, and particles, to... 

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