Coke oven, benzene release

Benzene releases in byproduct recovery operations Naphthalene residues generated in the final cooling tower Sulfur and sulfur compounds recovered from coke oven gas Wastewater from cleaning and cooling (contains zinc, ammonia still lime, decanter tank tar, or tar distillation residues)... 

First, points of release of benzene were identified petroleum refining and coke oven operations (production and extraction releases), use as a chemical intermediate (transportation, storage, use, and waste releases), use in gasoline (use-related release), and use in finished products (use-related release). Benzene also can be a contaminant of most of the derivatives made from it and its use as a solvent was substantial before health concerns arose. The complexity of the chemical systems dependent on benzene is shown in Figure 6. A list of potential releasing products appears in Table II. 

Byproduct Recovery. Coke-oven gas is released during the coking process. A typical composition for raw coke-oven gas is given in Table 19.9. In addition to the components shown in the table, raw coke-oven gas also contains various contaminants, such as tar vapors, light oil vapors (mainly benzene, toluene, and xylene), naphthalene, ammonia, hydrogen sulfide, and hydrogen cyanide. The... 

The production of coke by the carbonization of bituminous coal leads to the release of chemically complex emissions from coke ovens that include both gases and particulate matter of varying chemical composition. The chemical and physical properties of coke oven emissions vary depending on the constituents. The emissions include coal tar pitch volatiles (e.g., particulate polycyclic organic matter, polycyclic aromatic hydrocarbons, and polynuclear aromatic hydrocarbons), aromatic compounds (e.g., benzene and jS-naphthyl amine), trace metals (e.g., arsenic, beryllium, cadmium, chromium, lead, and nickel), and gases (e.g., nitric oxides and sulfur dioxide). 

Coke is a carbonaceous residue derived from crushed bituminous coal from which the volatile constituents have been driven off by baking in a series of airless coke ovens at up to about 1200 °C. Thereby, the fixed carbon and residual ash are fused together. The released coke-oven gas is cleaned (Figure 5.1.29) and used as fuel (coking) gas, for example, in former times as town gas. Thereby, chemicals like tar, naphthalene, and benzene are separated, although the role of these products is small compared to crude oil based chemicals. Details on blast-fiimace coke production are given in Section 6.5.2. 

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