A device for microwave fluidized drying lignite

[0018] see figure 1 , figure 2 , The device for microwave fluidized drying of lignite includes a microwave heating chamber 1. The bottom of the microwave heating chamber 1 and the fluidized bed 2 are connected by a flange 3, and the flange 3 is provided with a connecting microwave heating chamber 1 and the fluidized bed 2 Material hole 18; the microwave heating chamber 1 includes a cylindrical metal furnace shell 4 that can shield microwaves. The top of the furnace shell 4 is provided with a material inlet 5 and a flue gas outlet 6, and the furnace shell 4 is provided with 4 microwave generating devices along the circumference It can be fed into the microwave heating chamber 1. The microwave generating device is composed of a microwave feed port 8 provided on the furnace shell 4 and a microwave source 9 installed on the microwave feed port 8. The interior of the furnace shell 4 is also provided with a microwave penetrating The cylindrical ceramic furnace tube 10 has a 5-section cylindrical structure from the top to the bottom. The circular metal baffle 11 is arranged between two adjacent sections. The cylindrical ceramic furnace tube 10 is also divided into 5 sections. And correspondingly installed on the baffle 11 inside the furnace shell and on the flange 3, the snap ring 26 is used to fix the ceramic furnace tube, and the multilayer metal baffle 11 from top to bottom along the inner side of the ceramic furnace tube 10 is used for To accept the materials and delay the downward speed of the materials, a venting hollow shaft 12 is arranged in the center of the ceramic furnace tube 10, and a number of rake-shaped structural members 14 are axially fixed on the venting hollow shaft 12 corresponding to the metal baffles 11, which are ventilated hollow. A conical material guide plate 20 is fixed on the shaft 12 above each rake-shaped structural member 14. The outer wall of the ventilated hollow shaft 12 is provided with a number of gas nozzles 13 corresponding to each rake-shaped structural member. The high-speed airflow disturbs the upward airflow in the microwave heating chamber 1 to increase the gas-solid contact area between the hot air and the material; the function of the guide plate 20 is to evenly distribute the material dropped by the upper metal baffle 11 on the lower metal baffle 11 Above, the function of the rake-shaped structural member 14 is to rake and drop the material on the metal baffle 11 toward the middle. The ventilating hollow shaft 12 is connected to the hot blast stove 15 through the hot air inlet pipe 21; the lower part of the fluidized bed 2 is provided with air The air chamber 23 is connected to the hot blast stove 15 through the hot air inlet pipe 22, and the air distribution plate 25 is arranged in the air chamber 23; the upper part is provided with an overflow pipe 16 connected to the finished product warehouse 17; and also includes an exhaust gas circulation processing system 7, The tail gas circulation treatment system 7 includes a conventional gas-solid separation device and a dehydration device connected to it. The inlet of the tail gas circulation treatment system 7 is connected to the flue gas outlet 6, and the gas outlet is connected to the hot blast stove 15 through the gas distribution valve 25 through the blower 19 , The solid outlet is connected to the finished product warehouse 17 through the material return pipe 24.

[0019] The working process of the present invention:

[0020] The raw material lignite (see solid arrow) with a moisture content of 30% or more and a particle size of 10mm or less is added from the material inlet 5. The ventilated hollow shaft 12 is driven by the motor to rotate at a uniform speed, and at the same time drives the rake fixed on it The structural member 14 and the material guide plate 20 rotate at a uniform speed, and the materials are evenly distributed on the metal baffle plate 11 provided on the inner wall of the ceramic furnace tube 10 through the material plate 20 from top to bottom. During the rotation, the shaped structure 14 will rake the material falling into the metal baffle 11 from the outside to the center, and then drop into and pass through the guide plate 20 and the metal baffle 11 step by step, so that the material is in an "S" shape from the top. The material is heated and pre-dried by the microwave device in the microwave heating chamber 1; the hot air (200℃~220℃, oxygen content below 10%, see the dotted arrow) of the hot blast stove 15 is pressurized by the blower 19 and then passed through The hot air inlet pipe 21 and the hot air inlet pipe 22 enter the ventilation hollow shaft 12 and the air chamber 23 under the fluidized bed 2. In the fluidized bed 2 the hot air is evenly distributed through the air distribution plate in the air chamber 23 and then enters the upper fluidized layer ; Hot air enters the microwave heating chamber 1 from the material hole 18, flows from bottom to top, forms a countercurrent with the material, exchanges heat with the continuously added material, and further heats the drying material; the horizontal high-speed hot air flow from the gas nozzle 13 disturbs the microwave The upward hot air flow in the heating chamber 1 increases the gas-solid contact area with the material. Under microwave irradiation, the moisture in the material is quickly separated and is brought out in time by the hot air flowing from bottom to top. The temperature of the hot air is higher than the water vapor dew point by more than 5°C. After the material is heated and dried in the microwave heating chamber 1 by mixing microwave and hot air, the free water content is reduced to less than 5% and falls into the fluidized bed 2 through the material hole 18.

[0021] In the fluidized bed 2, the hot air drives the material into a fluidized state for deep drying, and the water in the material is further separated, and the free water content is reduced to less than 0.2%, and it overflows into the finished product warehouse 17 through the overflow pipe 16 .

[0022] The tail gas discharged from the flue gas outlet 6 enters the tail gas circulation treatment system 7. After conventional technology gas-solid separation and dehydration, the gas is circulated into the hot blast stove 15 through the gas separation valve 25, and the waste heat is recovered; the solids separated from the tail gas circulation treatment system 7 The material enters the finished product warehouse 17 through the return pipe 24.

[0023] The ventilated hollow shaft 12 in the above embodiment may also be a non-ventilated rotating shaft, and basically the same function can be achieved without the hot air intake pipe 21.