Thermal integration of heat transfer fluid systems

Appropriate integration of subsystems results in an energy-efficient and cost-effective design of the overall system. In many industrial applications, heat transfer fluid (HTF) is used to supply required amount of heat to multiple heat demands from a single heat source. Appropriate integration of fired heater with a process leads to overall reduction in energy requirement as well as capital investment. In this paper, four methodologies are developed to integrate fired heater appropriately with a process. Firstly, a targeting methodology is proposed to determine the minimum HTF flow rate to supply heat from single heater to multiple heat demands. Secondly, a methodology to integrate radiant fired heater with a process through HTF is discussed. Thirdly, indirect integration of fired heater, incorporating energy recovery from flue gas through the air preheater, is developed. Finally, improvement of overall energy efficiency by utilizing process heat below pinch through air preheating is demonstrated. It is also illustrated that the number of fired heater can be reduced, and hence, the total cost of the system can also be reduced by indirect integration. (c) 2013 Curtin University of Technology and John Wiley & Sons, Ltd