Design And Performance Analysis Of Gas Turbine Based On Oxy-fuel Combustion

With the gas-steam combined cycle system in the field of power generation widely used,gas turbine as the top circulation of the power generation system,people pay more and more attention to its thermal performance.With the development of environmental protection policies and people’s awareness,the requirements for CO₂emission and control are also becoming more and more stringent,Oxy-fuel combustion technology is the pure oxygen and air,part of the cycle of flue gas mixing,as the air instead of the combustion of gas as an oxidant to increase the concentration of CO₂ in the exhaust,Conducive to CO₂ enrichment and storage.Oxyfuel combustion technology provides a technical solution for the clean combustion of gas turbines.In this thesis,the main thermal parameters,performance indicators,ideal cycle and the actual cycle thermal characteristics of the gas turbine are analyzed.Combined with the purpose and characteristics of the modeling and simulation studies,the main components of the gas turbine are mathematically modeled,and the thermodynamic calculation Model,combustion chamber thermal calculation model,gas turbine calculation model and device efficiency and output efficiency model.Secondly,according to the thermodynamic design and calculation process of gas turbine,EBSILON simulation software is used to build the thermodynamic system of Oxyfuel combustion gas turbine,and the thermal calculation is made.Then the structure type of oxy-fuel combustion gas turbine is selected.Under the condition of clear thermal design index,the optimal pressure ratio of the group isπ=11.18,so that the specific thermal parameters of oxy-fuel combustion gas turbine can be calculated.Finally,the unknown parameters were determined based on the calculation of the design conditions.The gas turbine with Oxyfuel combustion was subjected to variable working conditions.The changes of the gas turbine load,the change of O₂concentration and the change of pressure ratio were analyzed.Impact.The T₃ control strategy is adopted when the unit is under variable load operation.There are two operation schemes in this strategy（see Chapter 4 in detail）.The calculation results show that when the unit is under load operation,the difference between the above two kinds of operation schemes affects the overall thermal performance of the unit And can be approximated as the same.When discussing the influence of the concentration of oxidizer O₂ on the unit performance,the T₃ and the unit load are maintained constant by changing the mass flow of the oxidizer,the flow of natural gas and the oxidizer equivalence ratio.The results show that:When the mass fraction of O₂ is below 22%,the unit specific power increases with the increase of O₂ mass fraction in the oxidizer.When the mass fraction of O₂ in the oxidizer is higher than 22%,the unit specific power remains almost constant.The numerical value is 595kJ/kg,the unit efficiency increases with the increase of the mass fraction of the oxidizer O₂.When discussing the effect of the pressure ratioπchange on the thermal performance of an oxy-fuel combustion gas turbine,two control schemes are adopted,Scheme B（see Chapter 4 in detail）,under the rated load,the unit transformation ratio operation,if you need the optimal work,can be lower than the design pressure ratioπ=11.18Using program A control,higher than the design pressure ratioπ=11.18 using the program B control;if the optimal efficiency can be lower than the design pressure ratioπ=11.18 using the program B control,higher than the design pressure ratioπ=11.18 when using program A control.