Retrofit and Exergy Analysis of Fluid Catalytic Cracking Unit Using Heat Recovery Approach Temperature as Decision Criterion

Abstract

Optimum and economic operation of any process plant depends on the right selection of ΔTmin. The estimated optimum ΔTmin for the investigated fluid catalytic cracking unit was 20 °C instead of the prevailing 109 °C. The pinch point was also found to be 127–107 °C. There was a reduction in the process stream exergy loss from 9.11 MW in existing network to 3.83 MW in the proposed network. Energy cost saving of $2,189,041.60 was achieved by the proposed network. The economic implications of heat recovery improvement were modifications to the cold crude feed from tank inlet to the main fractionator, removal of split in the boiler feed water from deaerator stream and proper positioning of 17 barg steam generator. The capital cost for plant modification was $3,220,238.11 with payback period of 1.5 years.