Analysis of Carbon Dioxide (CO2) Emission by Heat Recovery Steam Generator (HRSG)

This research is about to analyze the carbon dioxide (CO2) emission of the Heat Recovery Steam Generator (HRSG). The exhaust heat from the Gas Turbine (GT) released to the environment consists of CO2 and other air pollutant emission, which contribute to the global warming and the greenhouse effect. The main objective of this project is to study the carbon dioxide (CO2) emission by HRSG, which is fueled by exhaust gas heat from the GT and when 100% of exhaust gas heat from the GT is emitted to the environment. Block diagram energy models are develop based on the principle of First Law of Thermodynamics, mass and energy models. Using mass and energy balances for each subcomponent of HRSG and for the exhaust gas heat from GT, computations of energy contents and flow are possible for thermodynamics analysis. THREE (3) assumptions are used for CO2 analysis; i. The flow rate of flue gas is kept constant as 19.22 kg/s, ii. The inlet and outlet temperature of evaporator is set as 95oC and 180oC respectively and iii. The temperature of hot gases at economizer is set to 182oC. The result of 100% of waste heat emitted to the environment is compared with the waste heat used by the HRSG for the conversion of steam. It is noted that the amount of CO2 emission by HRSG is inversely proportional with the amount of CO2 emission by the exhaust heat from GT because at 8am, the maximum amount of CO2 emission by HRSG is the minimum amount of CO2 emission by the exhaust heat from GT. By comparing these values, it is noted that HRSG contributes about 32.21% of CO2 emission at UTP GDC in comparison to the exhaust heat from GT when it is 100% emitted to the environment. Moreover, it is noted that the amount of CO2 emission by HRSG is less than when 100% of exhaust heat is emitted to the environment by approximately 35.59%.