(219b) Maximizing Propylene through Catalytic Cracking: Indmax Fluid Catalytic Cracking (I-FCC) Process

Worldwide demand for propylene is growing faster than the anticipated supply from ethylene plants. Fluid Catalytic Cracking (FCC) units are the second largest source of propylene and are expected to fill much of the propylene supply-demand gap. On purpose production of propylene from FCC units assumes added significance when integrating refinery and petrochemical complexes for maximizing margins by conversion of lower quality feed stocks into higher value products.

Conventional FCC technology yields approximately 3 - 5 wt% propylene. The propylene yield approaches 8-10 wt% from conventional FCC units with the use of shape-selective catalytic additives and changes in operating conditions. The I-FCC process can produce more than 20 wt% propylene yield, depending on the feedstock quality, and can accept a wide range of feed stocks including residue.

I-FCC process is based on conventional FCC process and is designed and operated in the Indmax mode. The Indmax mode or technology has been developed by the Indian Oil Corporation's Research and Development Center to produce light olefins from heavy feedstocks using the FCC reaction system. The heart of the Indmax technology is the novel multi component, multifunctional, catalyst formulation. This catalyst formulation along with the operating conditions that consist of high temperature, short contact time, and low hydrocarbon partial pressure achieves very high conversion and selectivity to propylene. Different catalyst components crack molecules of different shapes and sizes present in the feedstock producing a synergistic effect that results in selectively cracking different feed components for maximum propylene/olefins production.

In addition to maximizing propylene, yield of ethylene and butylenes in the I-FCC process is also much higher compared to the conventional FCC process. Ethylene and butylenes recovered from the I-FCC unit can be combined to make additional propylene through metathesis. Molar ratio of ethylene is nearly equal to butylenes and no import of ethylene is required for this purpose. The yield of propylene can be increased to over 32 wt% using metathesis technology.

Hardware for the I-FCC unit is designed by ABB Lummus Global. This hardware works in concert with the catalyst and the operating conditions to realize full potential of the feedstock to produce propylene/light olefins. The hardware design, described in this paper, promotes high conversion and selective component cracking to achieve the desired results.