Exergy analysis of Naphtha Hydrotreating Unit (NHU)

The aim of this research work is to develop an exergy analysis of Naphtha Hydrotreating Unit of the Kaduna Refinery and Petrochemical Company (KRPC). This was achieved through extraction of data from the Laboratory operating manual and the process flow diagram of the naphtha hydrotreating unit of the refinery which is used in the simulation; the site of primary exergy destruction was also determined. The major components of exergy efficiencies of the major component were determine. Also the potential for process improvement through revamp was determined. Exergy analysis of Naphtha Hydrotreating Unit (NHU) of the Kaduna Refining and Petrochemical Company was successfully simulated using Aspen HYSYS. Exergy efficiencies were found to be very low in Heaters 11H01 and 11H02 at 23.9% and 50.0% respectively. Similarly low efficiencies were respectively observed in Columns 11C02 and 11C01 at 48.7% and 52.8%. The major contributors to exergy destructions were found to be Column 11C01 and Heater 11H01 with percentage contribution of 21.6% and 14.6% respectively, totaling 36.2% of the total irreversibility recorded in the NHU process. Heat recovery from flue gas in the furnace and boilers was considered and found to be economically viable with a payback period of less than one year.