New developments enhance attractiveness of Flexicoking technology

The first commercial Flexicoking unit was started up at the Toa Oil Company in Kawasaki, Japan, in September 1976. Feed rates of 110 to 115 percent of design have been demonstrated, along with 97-percent gasification of the gross coke to give a reliable supply of low-heating-value gas to the refinery. In general, the Toa Flexicoking unit operation can be judged as excellent. Several new developments in the Flexicoking area are expected to enhance its attractiveness for vacuum resid upgrading projects. One development is integration of the coking reactor with a vacuum pipestill to increase liquid yields. Another development is dual-gasification Flexicoking, whereby synthesis gas is produced in addition to the normal product slate. Gas treating is an integral part of the Flexicoking process, and studies have shown that methyldiethanol amine (MDEA) cleanup of the lowheating-value coke gas may offer several advantages over the Stretford process.