To prevent a heat transfer tube from being exposed to corrosive combustion gas by a method wherein the retaining heat of waste gas is recovered by heat transfer to solid particles at first, then, the retaining heat is recovered as steam by contacting the heat transfer tube to the solid particles.
Wastes 1 are supplied into a combustion furnace 2 to burn them. The exhaust gas of combustion is turned by a bulkhead 3 at the upper part of the combustion furnace to send the same into the fluidized bed heat exchanger 5 of a first stage. The fluidized bed heat exchanger 5 of the first stage receives the sand of 700°C from a first stage fluidized bed heat recovery furnace 13 through a particles returning pipe 18 and discharges the sand of 750°C from a particles transfer pipe 16. The exhaust gas, discharged out of the first stage fluidized bed, is sent into a second stage fluidized bed heat exchanger 6. The second stage fluidized bed heat exchanger 6 receives the sand of 390°C and discharges the sand of 440°C. The pressurized water of 60°C is supplied to the heat transfer tube 11 of a waste heat recovering device 10 to heat the same to the degree of 230°C. The pressurized water is introduced into a heat transfer pipe 28, installed in a second fluidized bed heat recovering furnace 14, to change the same into the water vapor of 342°C and, thereafter, the water vapor is heated to 600°C by another heat transfer pipe 29, installed in the first fluidized bed heat recovering furnace 13.
MIZUMOTO MAMORU
ITO OSAMU
ORITA HISAYUKI
SATO YOSHIO
AZUHATA SHIGERU
