Oxygen process

In oxygen steelmaking, 99.5% pure oxygen gas is mixed with hot metal, causiag the oxidation of the excess carbon and siHcon ia the hot metal and thereby produciag steel. In the United States, this process is called the basic-oxygen process (BOP) (4,9,10). The first U.S. commercial iastallation began operation in 1955. 

Top-Blown Basic Oxygen Process. The top-blown basic oxygen process is conducted ia a cylindrical furnace somewhat similar to a Bessemer converter. This furnace has a dished bottom without holes and a tmncated cone-shaped top section ia which the mouth of the vessel is located. The furnace shell is made of steel plates ca 50-mm thick it is lined with refractory 600—1200-mm thick (11). 

Because the basic-oxygen process uses a refining agent containing practically no nitrogen, the product has a low nitrogen content. Oxygen residues depend on the carbon content. 

Residual alloying elements such as copper, nickel, or tin are usually considered undesirable. Their main source is purchased scrap. Because of the generally high consumption of hot metal in the basic-oxygen process, the residual alloy content is usually sufficiently low, depending on the quaUty of the purchased scrap. 

Some hydrogen cyanide is formed whenever hydrocarbons (qv) are burned in an environment that is deficient in air. Small concentrations are also found in the stratosphere and atmosphere. It is not clear whether most of this hydrogen cyanide comes from biological sources or from high temperature, low oxygen processes such as coke production, but no accumulation has been shown (3). 

Raw Material Purity Requirements. The oxygen process has four main raw materials ethylene, oxygen, organic chloride inhibitor, and cycle diluent. The purity requirements are estabHshed to protect the catalyst from damage due to poisons or thermal mnaway, and to prevent the accumulation of undesirable components in the recycle gas. The latter can lead to increased cycle purging, and consequently higher ethylene losses. 

The air process has similar purity requirements to the oxygen process. The ethane content of ethylene is no longer a concern, due to the high cycle purge flow rate. Air purification schemes have been used to remove potential catalyst poisons or other unwanted impurities ia the feed. 

Both air and oxygen processes can be designed to be comparable in the following areas product quaUty, process flexibiUty for operation at reduced rates, and on-stream rehabiUty (97,182). For both processes, an on-stream value of 8000 h/yr is typical (196). The rehabiUty of the oxygen-based system is closely linked to the rehabiUty of the air-separation plant, and in the air process, operation of the multistage air compressor and power recovery from the vent gas is cmcial (97). 

Secondary Brass and Bronze Production Plants Primary Emissions from Basic Oxygen Process Furnaces for Which Construction Commenced after June 11, 1973... 

Secondary Emissions from Basic Oxygen Process Steelmaking Facilities for Which Construction Commenced after January 20, 1983 Sewage Treatment Plants Primary Copper Smelters Primary Zinc Smelters... 

Increasingly today, steels after they have been tapped (poured) from the furnace undergo a further stage of processing called secondary steelmaking before the steel is cast. This applies to both the basic oxygen process route and to the electric arc furnace route. 

Introduction (in Austria) of the basic oxygen process , now by far the most common process for making steel. 

Tu, S.-C. (1991). Oxygenated flavin intermediates of bacterial luciferase and flavoprotein aromatic hydroxylases enzymology and chemical models. Adv. Oxygenated Processes 3 115-140. 

FIGURE 16.40 In the basic oxygen process, a blast of oxygen and powdered limestone is used to purify molten iron by oxidizing and combining with the impurities present in it. 

The enzymatic oxygenation process is of particular value as there is a significant difference in the formation rates of sulfoxides and sulfones. The initial conversion of sulfide to the optically active sulfoxide by an MO is usually very fast compared to the subsequent oxidation step to sulfone, upon which chirality is lost (Scheme 9.26). In many cases, over-oxidation to sulfone is not observed at all when employing MOs. 

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