Stepwise optimization of hydrogen network integrated sulfur compound removal kinetics and a fluid catalytic cracker

Abstract

The hydrogen consumption in refineries is rapidly growing because more sour and heavy crude oils are being processed to produce more transportation fuels and meet increasing market demands. A hydrogen network integration (HNI) strategy including two mathematical models (M1 and M2) is built to reduce the hydrogen consumption and the total cost based on the sulfur compound removal (SCR) kinetics and a fluid catalytic cracker (FCC). M1 is an operational optimization model integrated the SCR kinetics and an FCC to reduce the hydrogen consumption by optimizing the degrees of impurity removal and operating conditions of hydrotreating units. M2 is an HNI model to optimize the hydrogen network structure based on the results from M1. The case study shows that the HNI without kinetics and FCC only reduces by 19.1% and 32.6% in total annualized cost (TAC) and hydrogen consumption. While in the hydrogen network optimization with SCR kinetics and FCC, the reductions of the hydrogen consumption and TAC have reached to 47.9% and 37.1%, which are also more than the reductions of 44.5% and 34.4% in the optimization with lumped kinetics and FCC. Therefore, it is imperative to integrate the SCR kinetics and an FCC in a hydrogen network optimization.