Changes in the raw materials employed and the coking conditions affect the quality of the tar byproducts used in the production of electrode pitch. The decline in tar quality associated with faster pyrol ysis of the vapor-gas products within the coking chamber is discussed. The factors affecting the properties of the newly formed coal tar are analyzed, and the results are compared with theoretical concepts regarding the transformation of the primary products of pyrolysis in the coking chamber. Practical recommendations are developed regarding the production of higher quality tar. Systematic monitoring of the volume and temper ature of the free space within the chamber permits improvement in tar quality, despite increasing coking rates in the production of higher quality coke. With a tar density of 1185-1190 kg/m 3 , the moisture content falls to 2.0-5.5%, and the ash content to 0.08-0.11%.

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Existing methods of assessing coke in production conditions are analyzed. Significant deficiencies are noted in the gravimetric method of determining the yield of volatiles and in methods of determining the temperature of the coke leaving the coking chamber. Assessment of coke on the basis of a modified method of determining the yield of volatiles (by volume) at 1150°C is proposed. In the coke shops at PAO Zaporozh koks, samples of industrial coke are assessed by the proposed method. A close correlation is found between the yield of volatiles (by volume) and two important coking characteristics: the final temperature and the cok ing rate. Determination of the yield of volatiles by volume is currently used in the central laboratory at PAO Zaporozhkoks in continually assessing the coke produced and correcting the coking temperature.

At PAO Zaporozhkoks, the coke yield is determined experimentally as a function of the batch properties and the final coking temperature, in box coking. An empirical formula for the coke yield is obtained. With increase in the yield of volatiles from dry batch by 1%, the coke yield falls by 0.71%. With increase in the final coking temperature by 50°C, the coke yield falls by 0.35%.

The evolution of quality requirements on blast furnace coke indicates the need to use low sulfur imported coal of the required quality. The best performance characteristics of European blast furnaces are noted. At such furnaces, with the injection of pulverized coal, the consumption of low reactivity blast fur nace coke is 280.9-355.8 kg/t of hot metal. On the basis of the requirements imposed on coal used in the pro duction of low reactivity, low sulfur, high strength coke, an industrial coking method has been developed and tested at PAO Zaporozhkoks on the basis of Ukrainian, Russian, and United States coal of the required quality. The coke produced is tested in blast furnace 5 at PAO Zaporozhstal'. The results show that coke of improved quality may be obtained from batch containing 50% Ukrainian coal, 30% Russian coal, and 15% United States coal at PAO Zaporozhkoks. Thus, in the first 11 months of 2013, the quality of the blast furnace coke produced was as follows: moisture content 3.6%; ash content 11.0%; sulfur content 0.78%; M 10 = 6.3%; content of the >80 mm class 4.1%; content of the <25 mm class 3.1%; CRI = 31.8%; CSR = 51.9%.