Simulation and analysis of humid air turbine cycle based on aeroderivative three-shaft gas turbine

Due to the fact that the turbine outlet temperature of aeroderivative three-shaft gas turbine is low,the conventional combined cycle is not suitable for three-shaft gas turbines.However,the humid air turbine(HAT)cycle provides a new choice for aeroderivative gas turbine because the humidification process does not require high temperature.Existing HAT cycle plants are all based on single-shaft gas turbines due to their simple structures,therefore converting aeroderivative three-shaft gas turbine into HAT cycle still lacks sufficient research.This paper proposes a HAT cycle model on a basis of an aeroderivative three-shaft gas turbine.Detailed HAT cycle modelling of saturator,gas turbine and heat exchanger are carried out based on the modular modeling method.The models are verified by simulations on the aeroderivative three-shaft gas turbine.Simulation results show that the studied gas turbine with original size and characteristics could not reach the original turbine inlet temperature because of the introduction of water.However,the efficiency still increases by 0.16%when the HAT cycle runs at the designed power of the simple cycle.Furthermore,simulations considering turbine modifications show that the efficiency could be significantly improved.The results obtained in the paper can provide reference for design and analysis of HAT cycle based on multi-shaft gas turbine especially the aeroderivative gas turbine.

Design Research of a Novel Aftercool-Humidifier Concept for Humid Air Turbine Cycle

Humid air turbine cycle(HAT)has potential of electrical efficiencies comparable to combined cycle,with lower investment cost and NO_(x) emission.The typical heat exchanger network of HAT consists of intercooler(if there is),aftercooler,recuperator,economizer and humidifier,which brings higher efficiency but makes the system more complex.To simplify HAT layout,a novel humidifier concept is proposed by integrating the aftercooler into traditional counter-current humidifier.Based on this concept,a one-dimensional model including pressure drop and exergy calculation is established to distinguish the thermodynamic and hydrodynamic characteristics,and then the structural parameters,such as the number of rows and columns,tube diameter,pitch and type for a micro HAT are identified.The results show that the aftercool-humidifier plays the same role as original aftercooler and humidifier,and can match the in-tube air,out-tube air and water stream well with lower volume.In the case of micro HAT cycle,the volume of heat and mass transfer area can be reduced by 47%compared with traditional design.The major thermal resistance occurred in the convection heat transfer process inside the tube;however,using enhanced tube cannot effectively improve the compactness of device.