Heat exchanger network design for the optimization of total annual cost of the Catalytic Reforming Unit

Abstract

This research involved the energy integration of the Catalytic Reforming Unit of a Refinery using Aspen Pinch 11.1 Software. The operating data of the unit was analyzed on composite and grand composite curves from the Software to obtain an optimum minimum temperature of 15oC, pinch temperature of 149.5oC and hot and cold utilities targets of 37094 kW and 22440 kW respectively. Problem table algorithm (PTA) was used as a sensitivity tool to test the accuracy of these values; the exact same values were obtained with less than 0.4% difference between the energy targets. This integration achieved a minimum heat recovery (QREC) of 55465.00 kW with an increase in the number of heat exchangers from eighteen (18) to twenty one (21) with total area of 1995.80m2. Power law correlation was used for the heat exchanger costing to obtain a minimum Annual Capital Cost of $5,918.25/yr, Annual Energy Cost of $2,892.28/yr and Total Annual Cost (TAC) of $57,442.90/yr. By extension, these will certainly reduce the annual operating cost in terms of cost of utilities as well as minimize pollution emissions. Pinch analysis provides the best target for the minimum energy consumption as well as minimum total annualized cost.