ANALYSIS OF THE PRESENT STATE AND DEVELOPMENT TRENDS OF COAL TAR REFINING.

The expansion of the feedstock base for coking in the USSR due to the increase in the proportion of poorly-caking coal in the charges (especially gas coal at coking plants in the Ukraine) led to an increase in the yield of tar from the dry charge from 3. 30% (1970) to 3. 40-3. 45% (1980-1982). The change in the quality of the tar from a charge of one of the plants in the South on an increase in the proportion of gas coal from 24-32 (I) to 37-39% (II) is illustrated. The dynamics of the increase in volume of refining of coal tar in groups of plants with various design capacity for tar are presented. Data is presented from which it may be seen that in recent years plants with tar refining systems with higher capacity operate at lower feedstock loads, and consequently have more favorable conditions to improve the tar rectification process. In addition, 20% of the refined tar is fractionated under severe equipment operating conditions (up to 100 thousand tons of tar per year), at a load more than 25% above the design capacity. This unavoidably leads to an increase in the rate of flow of tar through tube oven, a more severe temperature regime of tar heating before fractionation, a decrease in the efficiency of the evaporation and condensation equipment, and increased wear of the equipment (tube oven, evaporators, column, etc. ), which still more greatly impairs the tar refining conditions and leads to a decrease in the yield and lower quality of the reactions. The data presented show that a significant quantity of the naphthalene-containing oils and not less than 40% of the wash oil fraction produced are used to produce a wide range of marketable oil products without removal of the naphthalene. This leads to non-recoverable losses of naphthalene with the oils, and in addition, the use of oils with a high concentration of naphthalene in other processes involves contamination of the environment.