Published January 1999
The deep catalytic cracking (DCC) process is a fluidized catalytic cracking (FCC) process modified to increase the production of light olefins from heavy oil feedstock. One commercial version, DCC Type I, maximizes selectivity to propylene and substantially increases the yield of ethylene. In a second commercial version, DCC Type II, isobutylene plus isoamylene selectivity is maximized. The two versions use different, novel zeolitic catalysts and their reaction conditions differ. The Type I operation produces a high-octane, aromatic naphtha rich in toluene and xylenes. Operating conditions are more severe than those in conventional catalytic cracking but less severe than in steam cracking.
Integrating DCC into a fuel or a petrochemical refinery can increase profit through new or increased sales of polymer-grade propylene, ethylene, alkylate, methyl tent-butyl ether (MTBE), and aromatics extracted from the naphtha (toluene, xylene, and benzene). Premium aromatic decant oil can be sold as electrode coke feedstock. Propylene and isobutylene are mostly by-products of steam cracking and of FCC. Demand for these by-products has been growing faster than demand for ethylene and motor fuels.
We conclude that a grass-roots DCC is most attractive in areas such as Asia where the value of propylene is high relative to gasoline. Savings in total fixed capital cost are possible, depending on the individual location. A nearby ethylene plant to process the ethylene, for example, could make an investment more attractive.
We review the economics of the propylene DCC version for a 40,000 bId grass-roots DCC unit operating in a fuels refinery on the U.S. Gulf Coast.
