(1.3 MMT) of the spent acid is recovered and sold. Most of the ash in crude oil probably remains with the refinery solid wastes and sludges. Assuming the crude oil contains 0.1 percent ash, there would be some 0.7 MMT of solid waste. The spent sulfuric acid (2.1 MMT) is presumably neutralized, either by reaction with some of the alkaline minerals (NaO, KO, MgO, CaO) in the crude oil ash, or by added lime.
Refineries also use materials purchased from other sectors in the refining process, including salt (0.72 MMT) and clays (0.122 MMT), which subsequently reappear mostly in solid or liquid wastes. Consumption of salt is reported, but its use is unclear; it may be a precursor to in-house caustic soda production (Gaines and Wolsky, 1981).
Mass flows in the petroleum, gas, and refinery sectors are shown in Figure 5. As noted above, the mass loss in refineries amounted to 55.6 MMT in 1988, or 7.6 percent of the mass of hydrocarbon inputs. This loss is partly fugitive emissions (VOCs), estimated to be 2 MMT, but most of these emissions are flared or recovered for refinery heat and power. Assuming that the missing mass consists mostly of molecules of the form CNH2N+2we can safely predict carbon content of between 80 and 85 percent, or about 45 MMT. This corresponds to an atmospheric oxygen intake of 120 MMT, eventual CO2 output of roughly 165 MMT, and water-vapor output of 76.5 MMT.
Dry wastes from the petroleum refining sector were about 1.25 MMT in 1981 (Science Applications International Corporation, 1985). Given the fact that neutralized sulfuric acid wastes alone would account for considerably more than this, we estimate the solid wastes from refineries to be 3-4 MMT (i.e., three times more than the SAIC estimate). EPA's estimate of total nonhazardous waste produced by the sector in 1985 was 150 MMT. Because the missing mass in the sector was only 55.6 MMT, including purchased inputs, and most of this must have been combustion products and VOCs, it is clear that most of the waste mass counted by EPA must have been water.
The chemical industry is far too complex to describe in adequate detail in the space available here. Our discussion is inevitably somewhat superficial. The major distinction is between inorganic and organic chemicals. The latter are derived mostly from natural gas, natural gas liquids, or petrochemical feedstocks.
Inorganic chemicals are derived either from nonmetallic minerals such as sulfur, phosphates, potash, soda ash, and salt or from the atmosphere. A few inorganics are derived from metal ores or metals. A summary diagram for phosphates, potash, and soda ash, beginning with extraction and beneficiation, is given