Light cracked naphtha processing: Controlling chemistry for maximum propylene production

As propylene market is expanding, new production paths have to be found. The cracking of light olefins contained in several naphthas seems to be a good alternative for responding to this demand. Results of light FCC naphtha cracking have shown that selectivity towards propylene is governed by hydrogen-transfer reactions. Thus, the selectivity to propylene may be increased by minimizing these reactions. This can be achieved by cracking the naphtha at high temperature, by using shape-selective catalysts or by working with coked catalysts. Recycling light naphtha in the FCC process is an interesting alternative, which may increase the yield of propylene by 50% if proper processing is carried out. Furthermore, olefins content of FCC gasoline may be significantly reduced.