A 200 MWe super-high pressure circulating fluidised bed boiler commercial operation test and performance analysis

A 200 MWe circulating fluidised bed (CFB) boiler with three cyclone separators was built in Inner Mongolia in China and tests were carried out with coal combustion process. The objective of this research is to investigate the effect of primary (secondary) air flow rate on the combustion process and the effect of multi-cyclone separators arrangement on solids circulation characteristics. Temperature profiles and pressure drops at different positions in the boiler chamber and cyclone separator diplegs were measured. Based on the measured temperature and pressure, heat flux and suspension density distribution in the chamber are derived and analyzed. Temperature, pressure, heat flux and suspension density profile along the height of the CFB boiler chamber and in the dipleg of cyclone separators with different operation conditions are given and discussed. The secondary air penetration depth in the dense area was test with different operation conditions and the effect of secondary air on combustion process has been investigated. The preliminary test results indicate that the solid distribution in the three parallel cyclone separators is non-uniform and future research is necessary to optimum the arrangement for multi-cyclone separators for large scale CFB boilers. Key issues on super-high pressure CFB boilers design, scaling up of CFB boilers and further work on computational fluid dynamics (CFD) simulation for hydrodynamic behaviour in the CFB boiler and cyclone separators are given in the end of this paper.