A novel suspension-floating-circulating fluidized combustion technology for coal slurry

A novel suspension-floating-circulating fluidized combustion technology is proposed for burning coal slurry fuel in traditional circulating fluidized bed boilers (CFBB). This technology can solve some existing problems in large-capacity CFBB burning coal slurry. The principles of the suspension-floating-circulating fluidized combustion technology were introduced in detail in this paper. A 130 t/h CFBB was retrofitted based on the technology, and the retrofitted system mainly includes a long-distance transport sub-system, a bed-material conveying sub-system with a wind-seal device invented by the authors, a superheater thermoregulation device using a novel temperature regulator, a return loop fluidization facility, and a pneumatic ash conveying sub-system with sealed pump. The achieved performance of the retrofitted CFBB shows that the thermal efficiency is 89.83 %, the combustion efficiency is 96.24 %, and the blending proportion of slurry is 94 %.