Technology

Summary

Olefins Conversion Technology (OCT) employs metathesis and isomerization chemistry to produce propylene from reacting ethylene with C₄ and/or C₅ olefins. Polymer Grade Propylene is readily produced in a simple catalytic fixed bed reactor without the use of super fractionators since no paraffins are formed in the metathesis or isomerization reactions. The OCT process does not require energy input to the reaction step. The OCT selectivity to propylene is over 95%. Unit capacity ranges from 60 KTA of polymer grade propylene to 800 KTA of propylene^[1].

Figure 1 - Metathesis of Ethylene and Butylene into Propylene^[2]

Features

Because the metathesis reaction does not produce propane, it is not necessary to install a propane/propylene splitter, which is typically installed in Steam Crackers and FCC. It helps to lower the investment cost and reduce utility consumption in the OCT process. Because metathesis reaction is an energy neutral reaction, utility consumption is significantly reduced. The major utility requirement is limited to fuel gas for controlling reactor inlet temperature and steam and cooling water for distillation^[2].

Figure 2 - OCT simplified PFD

C5’s OCT

Available C4’s from steam cracker is being reduced due to the increasing demand of butadiene and the decreasing amount of liquid feed cracking. C5’s OCT process is developed by Lummus Technology to make up shortage of propylene production and extend the feedstock for propylene production. The reaction schemes of C5’s OCT process are very similar to that of butenes OCT, consisting of isomerization and metathesis reaction. C5’s OCT is being regarded as a new propylene boosting technology to make up for shortage of C4s feed^[2].

Figure 3 - Reaction Scheme in C₅ OCT

References

1. LUMMUS TECHNOLOGY, Olefins Conversion (OCT)
2. Toyo Engineering Korea Ltd., Olefins Conversion Technology (OCT)