An automated approach for supertargeting of heating medium system

Heating utility system is commonly used in offshore platform to provide heating requirement for heavy crude oil of high viscosity from the reservoir. Heating the oil reduces its viscosity and hence improves oil/water separation which eventually leads to reduced size and cost of the separator. In conventional design, heating medium is distributed to the heat exchangers in parallel configuration to provide the required heating duties. This design however contributes to the overdesign of heating utility system. In this paper, a recently established process integration technique is extended to determine the optimum heating medium flowrate and minimum total annualised cost for a heating utility system. The newly extended technique makes use of the capital cost targeting approach based on pinch analysis technique, but implemented on an optimisation framework. The approach caters for capital and operating cost trade-off for the heat exchanger network (HEN) and waste heat recovery unit (WHRU) in the heating utility system. An industrial case study is used to elucidate the newly extended technique.