Combustion sulfur oxide formation

Pollutant Formation and Control in Flames Key combustion-generated air pollutants include nitrogen oxides (NOJ, sulfur oxides (principally SO9), particulate matter, carbon monoxide, and unburned hydrocarbons. 

The fact that Fischer-Tropsch fuels contain neither sulfur nor aromatics may become a strong selling point for the process. Less sulfur in the fuel has, of course, a direct effect on the sulfur oxides in the emissions, and the newly developed exhaust purification systems for lean burning engines that can be introduced means that all emissions, including GO2 and NOx, will diminish. Aromatics promote particulate formation in the combustion of diesel fuels and are therefore undesirable. We discuss this further in Ghapter 10. 

The presence of sulfur compounds in the combustion process can affect the nitrogen oxides, as well. Thus, it is important to study sulfur compound oxidation not only to find alternative or new means of controlling the emission of objectionable sulfur oxides, but also to understand their effect on the formation and concentration of other pollutants, especially NO,. ... 

In fuel combustion systems, S02 and S03 can form upon the burning of fuel sulfur. When sulfur oxides combine with water vapor, acids form. This problem of acid formation and accumulation is a known phenomena and usually occurs under low-speed and load operating conditions. The acids which condense on fuel system components can initiate corrosion of valves, piston rings, and fuel injector nozzles. 

Emissions of nitrogen oxides and sulfur oxides from combustion systems constitute important environmental concerns. Sulfur oxides (SO ), formed from fuel-bound sulfur during oxidation, are largely unaffected by combustion reaction conditions, and need to be controlled by secondary measures. In contrast, nitrogen oxides (NO ) may be controlled by modification of the combustion process, and this fact has been an important incentive to study nitrogen chemistry. Below we briefly discuss the important mechanisms for NO formation and destruction. A more thorough treatment of nitrogen chemistry can be found in the literature (e.g., Refs. [39,138,149,274]). 

Direct application of heat via in situ combustion or via superheated steam generation at the surface and injection are other effective methods to boost production, either in mature oil fields or in heavy oil fields where the petroleum is naturally quite viscous. While both formation heating methods achieve production rate improvements by viscosity reduction, the apparent simplicity of the in situ combustion concept is offset by the difficult separation of recovered oil from an aqueous solution containing nitrogen oxides, sulfur oxides, and other polar combustion products. The acids present in the aqueous phase contribute to the stability of the emulsions obtained from the producing wells and are highly corrosive to steel pipes and tanks. 

Hydro-carbon-based spray combusticni is associated with pollutant formation. These pollutants include the NO and NO2 (referred to as NOx), carbon monoxide (CO), particulate matter (soot), unbumed hydrocarbons (HC), and others such as sulfur oxides. Although pollutants form a small part of the overall exhaust gas composition, they are produced in such large quantities that they have become considerable environmental and health hazards. Therefore, poUutimi reductimi has become one of the most important aspects of spray combustimi research. A very effective approach to achieve this objective is to reduce pollutants at their source, and thereby contribute directly to the production of cleaner and more efficient spray combustion devices. 

The second problem that may arise when performing gasdynamic calculations is formation of pollutants, such as nitrogen oxides, sulfur oxides, CO, and unburnt hydrocarbons. Here, a difference between the frozen and equilibrium compositions of the expanding combustion products is much greater than that for the internal energies. 

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