Pollution from Petroleum Processing

This section describes the predominant gaseous, liquid and solid pollutants generated by the petroleum industry. It also explains why these pollutants can be harmful. Section 5 of this chapter describes selected pollution-control regulations, and Section 6 discusses technology for abating these pollutants. 

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Control of atmospheric emissions from petroleum refining can be accomplished by process change, installation of control equipment, and improved housekeeping and maintenance. In many cases, recovery of the pollutants will result in economic benefits. Table 30-26 lists some of the control measures that can be used at petroleum refineries. 

The effects of biochemical use are at various folds, but the major direct substation of biochemicals for petrochemicals is found at the upstream of chemical production processes. For instance, the oil distraction from crops is far less harmful than the oil extraction from petroleum. In the case of phenol, making phenol from plants is estimated to generate 80 percent less pollutants than making phenol from petroleum. Another example is limonene. Limonene derived from citrus fruit... 

We can observe this process by analyzing polluted air at various times during a day (see Fig. 5.28). As people drive to work between 6 and 8 a.m., the amounts of NO, N02, and unburned molecules from petroleum increase. Later, as the decomposition of N02 occurs, the concentration of ozone and other pollutants builds up. Current efforts to combat the formation of photochemical smog are focused on cutting down the amounts of molecules from unburned fuel in automobile exhaust and designing engines that produce less nitric oxide (see Fig. 5.29). 

The oxides of sulfur create global pollution problems because they have longer lifetimes in the atmosphere than the oxides of nitrogen. Some of the SO2 and SO3 in the air originates from biological processes and from volcanoes, but much comes from the oxidation of sulfur in petroleum and in coal burned for fuel. If the sulfur is not removed from the fuel or the exhaust gas, SO2 enters the atmosphere as a stable but reactive pollutant. Further oxidation by radicals leads to sulfur trioxide ... 

Table 1 shows a selection of the major inorganic chemicals that are produced in annual quantities of many millions of tonnes. Substances made in comparable amounts that are not listed include fuels and organic chemicals produced from petroleum, and construction metals such as iron. In many cases the basic chemical reactions used to produce the compounds in Table 1 are simple, although catalysts are often required (see Topic J5). The design of processes to make the most economical use of energy and raw materials, and to minimize polluting wastes, is, however, not straightforward. The raw materials needed include air (for N2 and 02), sulfur (mined as native S or obtained from... 

The family of hazardous pollutants also includes phenol and its nitro and chloro derivatives. They enter the aquatic environment through waste-waters from many industries, such as petroleum processing and production of plastics, dyes, cellulose, pharmaceuticals, etc., or as the products of pesticides decomposition. Phenols may also arise in drinking water from the reaction of natural humic and fulvic acids with chlorinating disinfectants. Even at non-toxic levels, they deteriorate the taste and odor of drinking water. To address the steady increase in water contamination with phenolic compounds and pesticides, the US Environmental Protection Agency (EPA) has included 26 phenoHc compounds and 32 pesticides and their metaboHtes in the list of priority contaminants. In accordance with regulatory requirements, the allowed tolerance hmit of these pollutants must not exceed O.lpg/L for individual species and 0.5 Xg/L... 

The environmental aspects of coal combustion have been a major factor in the various processes, and the movement of the fossil fuel base away from petroleum and natural gas to coal has increased the need for effluent/pollutant control for large, fossil-fueled power plants (Argonne, 1990). Very large amounts of coal are consumed in generating electricity and the emissions from power stations and similar industrial sources represent a potential, and considerable, environmental hazard. These power plants and the accompanying flue gas desulfurization processes emit effluents, which often are pollutants, and which by mere contact with the external environment or by (generally) simple atmospheric chemical transformations, may form secondary pollutants that are more harmful than the initial effluent/pollutant. 

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