Small Gas Turbine General Model Suitable For Distributed Energy Systems

Small gas turbine is not only the power equipment used for conversion of thermal energy into mechanical energy, but also is the equipment for providing waste heat in distributed energy systems. Although the small gas turbine power generation efficiency is not high, the energy utilization ratio is high in distributed energy systems. So the small gas turbine has the potential advantages for the users with large cooling and heating load to select. Therefore, it need to study small gas turbine power generation characteristics and waste heat characteristics, then build the small gas turbine general model which can provide a reliable reference to select appropriate model number of small gas turbine and appropriate configuration in distributed energy systems. The main work and results of this thesis are as follows:Firstly, each major component of the small gas turbine is modular modelled, to form the modules of the compressor, combustor, turbine, pipes and other components. Then each component module is combined into a complete small gas turbine model. Two model numbers of small gas turbine parameters are used to verify the accuracy and generality of the steady state model. The results show that in the full load conditions or partial load conditions, the static verification is accurate. So the small gas turbine model can be used in dynamic simulation.Secondly, small gas turbine model is used for dynamic simulation, when setting generation power ramp input, air mass flow rate, fuel gas mass flow rate and exhaust gas temperature are ramp change; pressure ratio changes little and still in the design range of operating conditions, it means that the compressor still maintain in high efficiency operation.Thirdly, the steady-state model of the small gas turbine is combined with heat recovery boiler model to form a distributed energy systems steady-state model. At15℃, small gas turbine running at full capacity, so the data of small gas turbine is essentially the same, while heat transferred in the heat recovery boiler is about3278kW, so the energy efficiency is76.88%. The error is1.18%which compared with design efficiency77.8%.Fourth, analysis the electricity consumption of the application cases, the small gas turbine model is used to simulate the actual power generation in different typical day. Then combined with the actual electricity consumption, select the appropriate small gas turbine model which provides the base load, so the small gas turbine basically running at full load operation, while the part-load operation time is short. In the simulation of power generation, the change of fuel gas flow rate in small gas turbine is same as the power generation; in the full load conditions, the change of flue gas flow rate is same as power generation too; in partial load conditions, due to the air flow rate is increasing, even if the fuel gas flow rate is reduced, the flue gas flow rate is still increasing trend.Fifth, analysis the optimization operation of the small gas turbine, during the hot climatic conditions, compressor inlet air cooling method makes the generation power increased. At temperature28℃to40℃, PGR changes from3.48%to7.19%.