A novel approach to integration of hot oil and combined heat and power systems through Pinch technology and mathematical programming

In this study, by using a combination of Pinch technology and mathematical programming, a new method was developed to integrate a hot oil system and a combined heat and power (CHP) generator to achieve maximum power generation. The integrated system consisted of a gas turbine (GT) as the top cycle and a hot oil system and an Organic Rankine Cycle (ORC) as the bottoming cycle. Reuse or regeneration and recycling of the hot oil between different heating duties in the heat exchanger network (HEN) enables hot oil HENs to be designed with mixed series/parallel arrangements instead of the parallel ones which allows a lower inlet hot oil temperature to the heating section of the CHP and a higher inlet ORC working fluid temperature to the ORC turbine to generate more power. That method was developed for the design of hot oil HENs to satisfy any supply conditions for the CHP. The optimum design of the CHP system was achieved through mathematical programming. The results of applying this new design method for a case study indicated that the total income of the conventional design method was 341 k$/year while the new method provided an income of 445 k$/year, a 30% increase.