Process Modification for Capital Cost Reduction in Total Site Heat Integration

Abstract

The TSHI (Total Site Heat Integration) methodology is extended in this paper to manipulate the Total Site Profiles (TSP) towards further decreasing the heat transfer area (HTA), and consequently the capital cost, of heat transfer units. In the first case study, the application of Keep Hot Stream Hot (KHSH) and Keep Cold Stream Cold (KCSC) on TSP reduces the heating and cooling duties resulting in a reduction of 8 % in heat transfer area (HTA) and a saving of 8 % in heat exchangers cost. In the second case study, when KHSH/KCSC principles is applied on the selected segment of the TSP while maintaining the enthalpy constant, the TSP shape is changed to provide a larger temperature driving force, this together with the reduced heating and cooling loads, reduce the HTA by 11 % and the heat exchangers cost by 12%. Process modifications to achieve the desired shape of TSP may be limited by technical feasibilities or economic reasons. However, the potential for the feasible/profitable modifications of the TSP shapes is worth to be analysed and studied as they can be enhanced by exploring the potentials to integrate neighbouring units such as services, businesses residential and even agricultural units, i.e. the locally integrated energy sector (LIES), a concept introduced by Perry et al (2008).