Even though circulating fluidized bed combustion (CFBC) technology is superior than pulverized coal combustion (PCC) technology, its utilization in India is still in the nascent stage. Hence, India needs more mathematical models for the design of new CFBC boilers at different operating parameters. The determination of water wall heat transfer coefficient is critical in the design of CFB boiler furnace. The present paper focuses on the prediction of heat transfer coefficient of water wall using two methods (empirical and mechanistic models) for different capacities of pilot and commercial CFB boilers. The predicted results compared with measured data of respective CFB boilers and the error between two methods on heat transfer coefficient was identified.
In the part of promoting the design of new CFBC boilers for India, the present paper gives the proposed height of upper furnace for the preliminary design of 210 MW CFBC boiler operating with three Indian lignite samples (Neyveli lignite, Surat lignite and Giral lignite) which are popularly available and used for commercial operations in India. The investigation of heat transfer coefficient was carried out at superficial gas velocity of 6m/s and bed temperature of 875°C.