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Fluidised bed combustion (FBC) is a technology which can use waste materials and low quality fuels along with coal. Mixed with wastes, coal can burn more efficiently. The present study aimed at the co-combustion of refuse derived fuels (RDF) with coal in a bench scale circulating fluidised bed combustor (CFBC). Tests were carried out at different ratios of RDF/coal at temperatures from 830 to 960°C. Compared with coal alone, RDF–coal mixtures gave a more uniform temperature distribution in the combustor and the emissions were lower when burning. Improved efficiency and stability of co-combustion were attributed to the higher volatile matter content in RDF. However, the advantages could be lessened if a too high secondary air ratio was used. NOx and SO2 emissions were due to the presence of S (mainly in the coal) and fuel N (more than S) in both fuels. The SO2 concentration decreased with increasing RDF rich in Ca in the fuel. It was shown that CFBC units could burn RDF efficiently and cleanly.

China has the largest number of 300MW circulating fluidized bed (CFB) boilers in the word within, built in a short period of several years. Now, there are 13 CFB units in operating and other about 50 CFB boilers under construction or will be under construction soon. Summarization and analysis of the operational performance of the 300MWe CFB units are conducted. The reliability, economy and emission of these unite are introduced. The problems in these units are summarized. Some advices for improvement and future research are given.

The circulating fluidized bed (CFB) combustion technology is one of the approved clean combustion technologies, and the power supply efficiency can be improved combining with the supercritical technology. A 600MWe supercritical CFB boiler is introduced in this paper. This boiler is designed based on the success of 300 MWe CFB boilers, which has a single furnace with three cyclones without external heat exchangers. There are twin furnaces and twin air distributors in the boiler. The water walls of the twin furnace above dense bed combines to a common fence wall with some channels to balance the pressure of the two furnaces. The smooth tubes are adopted in membrane water wall with mixing header. Six cyclones are located beside the furnace as well as six loopseals and six external heat exchangers. The hydrodynamic characteristic of water wall is available with the modeling prediction. And the performance of the 600MWe supercritical CFB boiler is also investigated.