• Bharat Heavy Electricals Limited

Circulating Fluidised Bed Combustion

BHEL CFBC boilers – the technology edge – BHEL manufactures state-of-the-art circulating fluidised bed combustion (CFBC) boilers based on Lurgi technology. Special design features: recycling hot cyclone for effective separation of solid particles, which are returned to the combustor; special fluidised bed heat exchanger (FBHE) for effective utilisation of energy in hot recycled solid particles; higher boiler efficiency even on part loads due to better burnability; excellent operational flexibility – part load down to 25 per cent MCR and ideally suited for wide load fluctuations; compact plant design; no heat transfer surfaces across gas flow in erosion prone combustor zone; independent reheat temperature control. Advantages of CFBC Technology: fuel flexibility; high carbon burnout; in-situ pollution control; excellent operability; simplified fuel preparation and feeding; compact plant design. Depending on the mode of operation of the CFB power plant (base load or variable load) as well as the plant size and the type of fuel used, the plant may be designed either with or without a fluid bed heat exchanger (FBHE). In FBHE equipped plants, the heat transfer surfaces for steam generation are located both in the combustor and in the FBHE. On leaving the recycling cyclone, a portion of the hot solids is diverted to the fluid bed heat exchanger where it is cooled before being returned to the combustor. The heating surfaces for economiser and superheat duty are typically installed in the convective pass. In CFB plants without a fluid bed heat exchanger, the entire evaporator heating surface is distributed over the combustor and the convective pass.