Fuel switch & unit load increase project

Key challenges

Due to firing mostly low-CV Indonesian sub-bituminous coals, all four boilers on this station were no longer able to meet full load demand and were de-rated by ~10%. In 2018, CLP investigated options to increase boiler load back to the original rating to meet energy demands during peak summer months. However, in 2020, CLP’s objectives changed due to a shift in local energy policy resulting in less coal usage – the latest objective being to improve plant reliability.

RJM Solution

RJM carried out several projects for this station. In 2018, a Generation Recovery Engineering Study was performed, to investigate what would be required to achieve full load generation with the low-CV coal basket. This study included a Plant Performance Review, Combustion CFD Modelling, Coal Bunker and Feeder Materials Handling Study, and a Coal Mill CFD Modelling Study. RJM installed Advanced Rotating Port Rings, supplied by our partner Enflotech of South Africa (formerly Coal Milling Projects), to increase mill capacity by 10-15% based on the original objective of increasing boiler load.

More recently, RJM has been supplying new replacement Rotating Port Rings to Castle Peak, to focus primarily on reliability rather than high performance.

RJM also designed and supplied an upgraded Coal Feeder Bathtub (the interface between the bunker and the feeder) to improve feeder reliability and reduce mill trips due to loss of coal flow which were being caused by blockages from wet coal.

Results

RJM’s Generation Recovery Engineering Study helped CLP make an informed decision about the future direction of the plant, and RJM’s supply of new replacement Port Rings are helping to support the customer’s ongoing mill maintenance programme.