USING A DECANTING CENTRIFUGE TO REMOVE HEAVY COAL-TAR PRODUCTS FROM COAL TAR

摘要

In recent years, coking ovens have increased in age and methods of smokeless discharge in the material have produced a considerable deterioration in the quality of coal tar. In particular, there have been increases in ash content and in the contents of substances insoluble in toluene and quinoline. No substantial improvements have been available from the scheme shown in Fig. 1 for conditioning coal tar operating at the Coke Company up to 2003. Also, the stores on standing have accumulated heavy products, which require periodic removal, which involves considerable labor. Utilizing these wastes remains an acute problem. With the closure of the tar-processing shop and the storage of tar, the problem of quality has become worse in that consumers have made demands and it is necessary to eliminate the heavy products from railroad cars. With the set of our own railroad cars of more than 100, the cleanup has fallen behind the rate of accumulation of the unmanageable sediment. Cascade settling is better, but it also requires periodic cleanup in the tar stores to remove the heavy products, which has given only a brief improvement in quality (for 8-10 months). After the latest cleanup of the heavy products in the stores, the ash content of the saleable tar has been reduced to 0.14-0.16 percent. As the heavy products have accumulated, the ash content has risen to 0.2 percent.