Analysis of Solar Aided Steam Production in a Pulverized Coal Boiler

A pulverized coal power plant is one of the main CO₂ release resources. The integration of the solar energy into a pulverized coal power plant assists it to reduce the coal consumption and CO₂ emissions. Among the types of the integration arrangements, the integration of solar thermal energy into the boiler has great potential for the energy saving and mitigation of the greenhouse gas emissions. The parabolic trough solar collector is a more mature technology with lower cost and risk in the near term, and a direct steam generation collector (DSG) is taken as a future development of the parabolic trough collector. This paper analyzes two types of integration arrangements on the basis of DSG: the arrangement before economizer and the arrangement after economizer. The heat from the solar field has an effect on the performance of the boiler. Through a case analysis of the integration of the solar energy into the boiler of a 600 MW pulverized coal unit, it is indicated that with the same direct solar radiation and solar collector area the coal and spraywater consumption is reduced due to the solar energy which replaces part of the coal supply to the boiler system under the condition of maintaining a constant rated evaporation capacity, and the arrangement before economizer has more coal reductions and less spraywater reductions than the arrangement after economizer, and the arrangement after economizer has better system stability in steam production than the arrangement before economizer. At last, conclusions regarding the integration of the solar thermal energy into a boiler are drawn from above analysis.