Minimization of start-up time of sojitz kelanitissa combined cycle power plant

Abstract

There are only three combined cycle power plants in Sri Lanka. Ceylon Electricity Board owns one power plant, and private companies own the other two. Combined cycle power plants start-ups can be divided into three categories such as hot, warm and cold. Most of the start-ups are hot start-ups due to varying demand in the Sri Lankan’s grid system. During start-up, power plant run at part load, which is inefficient. Because a portion of the steam generated is directed to the atmosphere during boiler warming up, it is essential to reduce the combined cycle power plants' start-up time. This thesis focuses on optimising hot start-up time without compromising equipment reliability.

The thesis is carried out on a combined cycle power plant in Sri Lanka. Parameters during hot start-ups between 2019 and 2021 were collected in a minute interval. After analysing the start-ups in 2019 and 2020, several experiments were carried out during 2020 and 2021 hot start-ups. For this purpose, the start-up operation was divided into sub-operations, and four critical operations which have a significant impact on start-up time were identified.

Operations such as G.T. Loading, High Pressure (H.P.) start-up vent operation, High Pressure (H.P.) steam bypass valve operation and new vent system operation were analysed, and the best optimum operation pattern was identified.