Fluid dynamics of a fluidized bed packed with heat exchangers. Final report

Two fluidized bed facilities were built, and tests were conducted. Initially, a 1-ft. gas-fired fluidized bed (GFFB) was built as a predecessor to a coal-fired fluidized bed (CFFB) facility, in order to study the bed dynamics and its interrelation with the heat transfer characteristics of immersed heat exchangers of different configurations. The unique feature of the GFFB was the capability of achieving different gas velocity distributions in the bed with the help of a specially designed gas distributor. The GFFB was operated to gain useful information on the influence of various operating parameters, such as the superficial gas velocity and its profile, the bed temperature (200/sup 0/F to 700/sup 0/F) and pressure (1 to 7 atm), and settled bed height (21 in. to 55 in.), on the bed expansion and heat transfer characteristics of vertical and horizontal tube bundles, and an inverted U-tube. Tests were also performed on an inverted U-tube with longitudinal fins, and two unfinned inverted U-tubes to study the effect of heat exchanger solidity (8% and 16%). Particle attrition studies were also performed at atmospheric pressure. The 1-ft., coal-fired fluidized bed was then built and initial tests were performed. Typical heat transfer and particle attrition data weremore » collected with a single vertical tube heat exchanger axially located in the bed. The behavior of deep and shallow beds, as observed in the GFFB, was confirmed. The one-foot CFFB was dismantled and a 30'' CFFB capable of operating up to 10 atmospheres is being constructed. The tasks accomplished on the GFFB and the one-foot CFFB during February 1976 to August 1980 are documented.« less