Abstract: The gas turbine in Tianjin IGCC demonstration power plant is fueled with light diesel oil and the synthesis gas with low calorific value. After desulfurization, the synthesis gas produced in the gasifier enters the gas turbine through the gas hybrid humidification system. In the synthesis gas exchange process, problems such as the temperature fluctuation in the entrance, the instability of combustion condition occur frequently, resulting in the chain tripping under some severe circumstances. The entrance temperature is a major factor that affects the stable operation of the gas turbine. In this article, the factors that influence the entrance temperature change are analyzed. It is concluded that water accumulated inside the turbine is the main cause of the entrance temperature decrease and direct tripping. Based on the analysis, the technological conditions, the pipeline drainage equipments and the system control logic are improved to prevent such problems from occurring again.

Key words: IGCC, gas turbine inlet temperature, syngas, gas turbine, syngas saturator