Coke use

Fluid coking uses two vessels a reactor and a burner coke particles are circulated between the two to transfer heat generated by burning a portion of the coke to the reactor. The reactor holds a bed of fluidized coke particles, and steam is introduced at the bottom of the reactor to fluidize the bed. 

Commercial calcium carbide, containing about 80% CaC2, is formed in the Hquid state. Impurities are mainly CaO and impurities present in raw materials. CO is usually collected for use as a fuel in lime production or drying of the coke used in the process. The Hquid calcium carbide is tapped from the furnace into cooling molds. 

Low sulfur and ash levels are required for high GTE, isotropic cokes used for carbon and graphite specialty products. Highly isotropic cokes are also the filler materials for producing graphite for nuclear reactors. The purity, particularly the boron content, is critical in this appHcation. Properties of typical needle and isotropic (regular) cokes are summarized in Table 1. 

TABLE 27-2 Chemical and Physical Properties of High-Temperature Cokes Used in the United States ... 

Dynamic Activity is an indication of conversion per unit coke using data from the MAT laboratory. 

Benzene and related aromatic compounds were hrst isolated from the gases given off during the heating of coal in the absence of air to produce a form of carbon known as coke, used in the manufacture of steel. That benzene had the molecular formula CgHg was determined in 1825, but it took over a hundred years to prove its structure even though its correct structure was suggested in 1865. 

Coke byproduct wastes. Coke, used in the production of iron, is made by heating coal in high-temperature ovens. Throughout the production process many byproducts are created. The refinement of these coke byproducts generates several listed and characteristic wastestreams. However, to promote recycling of these wastes, U.S. EPA provided an exclusion from the definition of solid waste for certain coke byproduct wastes that are recycled into new products. 

Table 21 reports the ash content and ash composition (determined by inductively coupled plasma-atomic emission spectroscopy, ICP-AES) for all of the calcined cokes used to fabricate the test graphites. It can be seen that the amount of ash and its make-up are variable, but are within the range observed for petroleum-based calcined cokes. Although the ash contents in all of the calcined cokes appear rather high, these materials may still be acceptable because many of the metallic species are driven off during graphitization. This aspect is addressed in the next section. 

Table 21. Ash content and composition of calcined cokes used to make the WVU graphites... 

Hi i-Temperature Coke (1173 to 1423 K or 1652 to 2102°F.) Essentially all coal-derived coke produced in the United States is high-temperature coke for metallurgical applications its production comprises nearly 5 percent of the total bituminous coal consumed in the United States. About 90 percent of this type of coke is made in slot-type by-product recovery ovens, and the rest is made in heat recovery ovens. Blast furnaces use about 90 percent of the production, the rest going mainly to foundries and gas plants. The ranges of chemical and physical properties of metallurgical coke used in the United States are given in TAle 24-3. Blast furnaces use about 90 percent of the production, the rest going mainly to foundries and gas plants. 

Many processes hevo been tried to free the coke used for smelting purposes from sulphnr. Mr. Cal-veiit recently proposed to apply small portions of chloride of sodium to the coke in the process of niaiiu. facturo, by which means the fuel was made more suitable foT the iron being freed from its sulphur, and in several experiments the iron made from this prepared coke was found much superior to the ordinary quality but the process has not yet been very ... 

Other methods that have been used in determination of the amount of moisture in coke include (1) extraction of coke using anhydrous methanol and the addition of calcium hydride with coal constituents (CaH2) from which the amount of released heat is measured, and (2) extraction of coke using anhydrous dioxan and measurement of the refractive index of the solution to determine its water content. Application of these methods to coal may be subject to error because of (1) interaction of the coal (in contrast to coke) with the calcium hydride, leading to chemical errors, and (2) the influence of extractable constituents on the refractive index of the dioxan. 

ASTM D-4239. Standard Test Methods for Sulfur in the Analysis Sample of Coal and Coke Using High Temperature Tube Furnace Combustion Methods. 

Infrared absorption is one of three standard test methods for sulfur in the analysis sample of coal and coke using high-temperature tube furnace combustion methods (ASTM D-4239). Determination of sulfur is, by definition, part of the ultimate analysis of coal (Chapter 4), but sulfur analysis by the infrared method is also used to serve a number of interests evaluation of coal preparation, evaluation of potential sulfur emissions from coal combustion or conversion processes, and evaluation of the coal quality in relation to contract specifications, as well as other scientific purposes. Infrared analysis provides a reliable, rapid method for determining the concentration of sulfur in coal and is especially applicable when results must be obtained rapidly for the successful completion of industrial, beneficiation, trade, or other evaluations. 

The C02 emission of the iron and steel industry accounts for about 40% of C02 emitted from the entire manufacturing industry in Japan, and the cutback of this emission has become an important issue. In the iron/steel industry, the largest emission comes from the cokes used in the reducing furnaces of iron ore. 

Other procedures include high-temperature tube furnace combustion methods for rapid determination of sulfur in coal and coke, using automated equipment. The instrumental analysis provides a reliable and rapid method for determining sulfur contents of coal or coke. By this method, total sulfur as sulfur dioxide is determined on a continuous basis. 

Properties of the petroleum cokes used in the present test are shown in Table III. The symbol MPC represents petroleum coke manufactured with the use of Minas heavy oil by the delayed coking process, and DPC and FPC are, respectively, petroleum cokes provided by a delayed coker and a fluid coker commercially available in Japan. 

Numerous publications (10 to 12) have appeared, principally from the GDR, on the required quality properties of brown coal and their influence on the quality characteristics of formed coke. Since the Rheinische Braunkohlenwerke AG is not engaged in formed coke production at present, raw material quality and coking behaviour are of interest only for the production of fine coke using the rotary hearth furnace (13> 14). 

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