Study On Cycle Characteristics Of Absorption Refrigeration Driven By Waste Heat From Gas Turbine

At present, the pipeline is the most common type of natural-gas transportation, and the gas turbine are widely used in the natural gas pressured station because of its good performance. But the performance of gas turbine is influenced by ambient temperature. The power output and efficiency of gas turbine decrease along with the temperature increasing. This problem can be solved by cooling the air inlet without changing its structure. This paper is based on the characteristics of the waste heat from gas turbine and its operation condition at natural gas pressured station for long distance pipeline. To meet the gas turbine’s needs for inlet air cooling, a fully-air cooling mode absorption refrigeration system is proposed. The system is driven by gas turbine waste heat using R124-DMAC as working fluid.When the ambient temperature is35℃and the required air inlet temperature is15℃, the cooling capacity needs to be1980.3kW, which is calculated in this paper. Using R124-DMAC as working fluid, the cycle thermal calculation and corresponding influencing factor analysis of the absorption refrigeration driven by waste heat from gas turbine are conducted under the design working condition (the condensing temperature is50℃, the evaporating temperature is3℃, the cooling capacity is1980.3kW). Based on the design loads, inlet parameters and outlet parameters of every heat exchanger, and the corresponding structure design are obtained. In addition, the mathematical models of every heat exchanger in the refrigeration system are established using steady distribution or lumped parameter method Then these mathematical models are transformed into Fortran programming language, in order to fulfill the system analog simulation using the changing temperature as the interface entrance and outputting every parameter of the cycle system.The numerical analysis results show that, when the ambient temperature is35℃and the analog simulation of the air inlet cooling system for gas-turbine displays steady, the evaporating temperature is3.3℃, the condensing temperature is50.2℃,the cooled air inlet temperature of gas-turbine is13.1℃,and the COP of this fully-air cooling mode absorption refrigeration system is0.475, which meets the initial design requires. When the ambient temperature is up to40℃,the system still operates steadily with high COP (0.452).All above prove that the designed absorption refrigeration driven by waste heat from gas turbine is feasible, which provide references for installing air inlet cooling system at the natural gas pressured station.