Dynamic simulation of a gas turbine for heat recovery at varying load and environment conditions

A novel solution of three-stage waste heat recovery from a gas turbine (11.35 MW) is proposed and its dynamic response characteristics with a series of load and environment change in the process of gas turbine operation is studied according to actual process requirements on an offshore platform. Integrating three processes under different temperature ranges is performed by using the flue gas to heat oil, generate steam and heat rejection water in turn with three heat exchangers (HE I, HE II and HE III), respectively. The dynamic simulation results show that the steam flow rate in HE II has obvious fluctuations as gas turbine load drops. Within the 10%, 20%, and 30% load decrease of gas turbine, the stabilized values of steam mass flow rate decrease by 7.6%, 16.3%, and 26.5%, respectively. The greater varying rate of the gas turbine load can accelerate the response speed but deteriorates system stability. The environment temperature change from 5 ?C to 25 ?C essentially affects the flue gas temperature from 473.18 ?C to 496.70 ?C, and it influences the system response linearly to a certain extent for the non-linear system expect for HE II. Since the phase transition process exists in HE II and the gas residence time is much shorter than liquid, the response speed and trend is different from the process in HE I and HE III.

Automated summary

A novel three-stage waste heat recovery solution is proposed for a gas turbine, with dynamic responses studied under different loads and environment changes. The steam flow rate shows fluctuations as the gas turbine load decreases, and the system stability is affected by the varying rate of load. Environmental temperature changes linearly influence the system response, but with differences in response speed and trend due to phase transition processes in different heat exchangers.