A Study on Energy Optimization of Heat Exchangers in a Gasification System

Abstract

The objective of this research is the optimization of energy parameters such as the temperature and flow rate of the fluid in heat exchangers in the gasification system in order to increase the recovery rate of energy in the system. A mathematical model of these heat exchangers is developed to predict their operating performance under the specified gasification system. The optimal flow rate and temperature of the fluid in the heat exchanger based on the effectiveness-number of transfer units(NTU) method is investigated. The result of the simulation shows that the optimal mass flow rate and temperature of the high pressure (HP) boiler feed water are determined at 175,907 kg/h and 110°C, respectively, while the optimal mass flow rate and temperature of high pressure saturated steam of boiler are determined at 238,430 kg/h, 290.5°C, respectively. At these values, the total heat amount obtained at these heat exchangers is highest with 169 MW. Besides, the total heat amount obtained at heat exchangers could be increased by 4.61% (7.8 MW) when sixty percent of the heat release amount from air cooler (12.78 MW) is used.