Oil shale semicoke fluidized combustion circulation gas heating technology

[0020] Hereinafter, the present invention will be further explained with the drawings and embodiments.

[0021] Reference figure 1 In the oil shale semi-coke fluidized combustion cycle gas heating process of the present invention, the oil shale semi-coke >0~15mm is fed from the feed port 3 into the fluidized bed furnace 1, and the remaining gas is fed from the remaining gas burner 4 Fluidized bed furnace 1, semi-coke and residual gas enter the fluidized bed furnace 1 and burn at low temperature at 850~950℃; part of the heat released by the combustion of semi-coke and residual gas in the fluidized bed furnace 1 heats the membrane walls around the furnace Part of the circulating gas flowing in the heat exchanger 2 flows through the high-temperature air preheating tube heat exchanger 19, the high-temperature gas heating tube heat exchanger 17, and the medium-temperature gas heating heating tube heat exchanger. 14 and the low-temperature air preheating tube heat exchanger 13, the flue gas temperature after heat exchange with the tube heat exchanger is 120~200℃, and it is discharged from the flue gas outlet 12. The high-temperature ash generated by the combustion of semi-coke enters the fluidized-bed slag cooler 9 from the slag discharge overflow 8. After being cooled, the high-temperature ash becomes a low-temperature ash, which can be directly transported to the slag yard. The fly ash produced by the combustion is carried by the flue gas and flows through the high-temperature air preheating tube heat exchanger 19, the high-temperature gas heating tube heat exchanger 17, the medium temperature gas heating heating tube heat exchanger 14 and the low-temperature air preheating tube in turn The heat exchanger 13 has a final temperature of 120-200°C and is discharged from the flue gas outlet 12. The cold primary air from the primary fan 11 sequentially passes through the low-temperature air preheating tubular heat exchanger 13 and the high-temperature air preheating tubular heat exchanger 19 to be heated into hot primary air and sent to the furnace 1, the temperature of the hot primary air is 350~450 ℃, higher than the ignition temperature of oil shale semi-coke, which is conducive to the ignition and stable combustion of semi-coke. The cold secondary air from the secondary fan 10 cools the high temperature ash and slag in the fluidized bed slag cooler 9 and becomes hot secondary air, which is sent from the secondary air nozzle 5 in the middle of the furnace 1 to supplement the oxygen required in the later stage of combustion , And make full use of the physical sensible heat of ash. The cold circulating gas from the cold gas main line 7 evenly enters the membrane wall heat exchanger 2 through the inlet header 6, and the cold circulating gas from the cold gas main line 7 enters the mixing header 18 through the regulating valve 15. After the wall heat exchanger 2 is heated, the circulating gas of 150~300℃ enters the middle temperature gas heating heating tube heat exchanger 14 at the rear, and the circulating gas is heated to 450~550℃ in the middle temperature gas heating heating tube heat exchanger 14. Then it enters the mixing header 18 and is mixed with the cold gas used for temperature adjustment in the mixing header 18, and the mixed circulating gas enters the high-temperature gas heating tube heat exchanger 17. The circulating gas is heated to 600~720℃ in the high temperature gas heating tube heat exchanger 17, and enters the hot gas outlet header 16. By adjusting the amount of primary and secondary air, semi-coke and remaining gas, the gas at the outlet of the furnace The smoke temperature is 850~950℃. The flow rate of the cold gas entering the mixing header 18 is adjusted by the regulating valve 15 so that the thermal circulating gas temperature of the hot gas outlet header 16 is less than 720°C, thereby avoiding the pyrolysis and carbon deposition of the circulating gas.