METHOD OF CONVERTING ACID TAR INTO ASPHALT Russian patent published in 2000 - IPC

FIELD: petroleum processing and petrochemical processes. SUBSTANCE: acid tar pH is raised to specified value within a range of 3-7 by mixing tar with pH- raising agent such as water, specified value of pH being sufficiently high to prevent acid tar from growing sandy and to provide its temperature to be within a range from 21 to 135 C. Resultant mixture contains layer mainly consisting of water and intermediate sludge layer, water resulting from chemical reaction between above-mentioned pH-raising agent and acid tar acid. Intermediate sludge layer is then separated from cauldron water to give a solid substance: intermediate sludge with some amount of water. The latter is heated to temperature between 100 and 275 C during period of time long enough to remove sludge water resulting in formation of soft asphalt. EFFECT: achieved more efficient utilization of acid tar. 39 cl, 8 dwg, 3 tbl