Improved coking design can up liquid yields

Certain design and operating steps can improve the efficiency of delayed cokers. This fact is important because during the last decade of the petroleum business, a significant change has taken place in the refining industry. Heavy, cheaper crudes are making up a greater part of our imports and refinery runs, while demand for residual fuel has declined. Of the 1982 refinery runs, 31% were heavy as compared to 21% of runs in 1979. (By definition, a heavy crude yields 15% or greater residuum at 1,050/sup 0/F.) Refiners are adding resid conversion to upgrade the heavier feedstocks to meet demands for economically competitive light products. A majority of refiners are turning to delayed coking to upgrade the low value fuel oil to more valuable lighter liquids.