[0024] Example
[0025] The specific implementation of the embodiments of the present invention will be described below with reference to the accompanying drawings.
[0026] figure 2 It is a schematic diagram of the structure of the fan mill three-medium drying direct blowing pulverizing system in the embodiment of the present invention.
[0027] like figure 2 As shown, the fan mill three-medium drying direct-blown pulverizing system includes a coal feeder 1, a downward drying pipe 2, a fan coal mill 3, a coarse powder separator 4, a coal powder distributor 5, a burner 6, and a furnace smoke port. 7. Volute inlet furnace smoke mixing chamber 8, air preheater 9, blower 10, dust collector 11, induced draft fan 12, cold smoke fan 13, secondary air box 14, chimney 15, lignite boiler 16. The lignite boiler 16 provided in this embodiment includes a furnace smoke port 7 and a volute intake furnace smoke mixing chamber 8 .
[0028] In the fan mill three-medium drying direct blowing pulverizing system, a part of the hot air from the outlet of the air preheater 9 and the cold smoke from the flue behind the induced draft fan 12 and the cold smoke conveyed by the cold smoke fan 13 first enter the volute inlet furnace. The upper part of the smoke mixing chamber 8 is mixed into a low-temperature gas, and the high-temperature furnace smoke extracted from the furnace smoke port 7 and the low-temperature gas are mixed in the volute inlet furnace smoke mixing chamber 8 to form a desiccant of the pulverizing system, which is mixed from the volute inlet furnace smoke. The desiccant from the chamber 8 is transported to the inlet of the downward drying pipe 2 through the high temperature furnace flue pipe 17, and the raw coal and the desiccant delivered by the coal feeder 1 are mixed in the downward drying pipe 2 and descend to complete the pre-drying of the raw coal, and then enter the fan together. Coal mill 3, the raw coal is further dried and ground into pulverized coal in the fan pulverizer 3, and at the outlet of the fan pulverizer 3, the coarse powder separator 4 separates the over-coarse pulverized coal and sends it back to the fan At the entrance of the coal mill 3, qualified pulverized coal and pulverized exhaust gas are discharged from the top of the coarse powder separator 4, distributed by the pulverized coal distributor 5, and sent to the furnace through the burner 6 for combustion. According to the present invention, one end of the volute inlet furnace smoke mixing chamber 8 is communicated with the furnace smoke port 7 , and the other end is communicated with the high temperature furnace smoke pipe 17 . The furnace smoke port 7 communicates with the furnace of the lignite boiler 16 . A 600MW lignite boiler is generally equipped with 8 fan coal mills, correspondingly 8 furnace smoke ports and 8 high temperature furnace smoke pipes.
[0029] image 3It is a schematic structural diagram of a volute inlet furnace smoke mixing chamber in an embodiment of the present invention. In the figure, A is a three-dimensional view, B is a front view, C is a left view, and D is a top view.
[0030] like image 3 As shown, the volute intake furnace smoke mixing chamber 8 includes a mixing part 81 and one introduction connection part 82, and the mixing part 81 and the introduction connection part 82 are in the shape of a volute as a whole.
[0031] The mixing part 81 is a circular tube, which communicates with the smoke outlet 7 of the furnace.
[0032] The lead-in connection portion 82 is a square tube, including a straight surface portion and a curved surface portion that are connected and communicated. One end of the straight surface part is communicated with the low temperature gas pipeline as the inlet 83 of the low temperature gas; Exit 84.
[0033] The curved portion also surrounds the outer wall tangent to the mixing portion 81 , the wrap angle of the curved portion to the mixing portion 81 is 160°, and the cross-sectional area of the curved portion tapers from the inlet 83 to the outlet 84 .
[0034] Under the action of the blower 10 and the cold smoke fan 13, the low-temperature gas is introduced from the low-temperature gas pipeline through the inlet 83, and enters the mixing part 81 tangentially from the outlet 84 in a volute type; under the action of the fan coal mill 3, the high temperature in the furnace The furnace smoke enters the mixing part 81 from the furnace smoke port 7 .
[0035] Figure 4 It is a schematic diagram of the mixing swirl flow formed in the volute inlet furnace smoke mixing chamber during operation in the embodiment of the present invention.
[0036] like Figure 4 As shown in the figure, the middle part of the figure is high temperature furnace smoke, and the surrounding area is low temperature gas.
[0037] Depend on Figure 4 It can be seen that the low-temperature gas entering the mixing part 81 tangentially from the low-temperature gas duct volute forms a strong swirling flow in the area near the wall surface of the mixing part 81, and the high-temperature furnace smoke entering from the furnace smoke port 7 is wrapped in the central area of the mixing part. .
[0038] Figure 5 It is the temperature distribution diagram of the longitudinal section of the volute inlet furnace smoke mixing chamber during operation in the embodiment of the present invention.
[0039] Figure 5 The curve in is the temperature contour, and the value on the curve is the contour temperature.
[0040] Depend on Figure 5 It can be seen that when the low-temperature gas swirls forward, the high-temperature furnace smoke with a temperature of about 1100 ° C is wrapped in the center, and at the same time, the low-temperature gas and the high-temperature furnace smoke in the center of the mixing part 81 continuously conduct heat transfer and mixing, so that the temperature of the mixed desiccant gradually tends to be higher. in uniform. This flow organization method for mixing and heat transfer of cold and hot air in the area away from the wall not only solves the problem of coking in the mixing chamber, but also solves the problem of cracking in the mixing chamber caused by uneven heating of the wall.
[0041] At the same time, by Figure 5 It can be seen that because a small part of the low-temperature gas entering the mixing part 81 tangentially rotates back to the furnace, a layer of low-temperature protective gas film is also formed at the wall surface of the furnace smoke opening 7, which avoids the high temperature furnace smoke directly scouring the furnace smoke opening 7. The wall surface also avoids the coking of the smoke port 7 of the furnace.
[0042] In practical applications, the wrapping angle of the curved surface portion introduced into the connecting portion to the mixing portion 11 ranges from 30° to 360°. As a modification of this embodiment, the introduction connection portion 12 may also be a circular tube.
[0043] Actions and Effects of Examples.
[0044] According to the volute inlet furnace smoke mixing chamber provided in this embodiment and the lignite boiler including the same, since the introduction connection part and the mixing part are integrally volute type, the low-temperature gas is tangentially introduced into the mixing part in a volute type at a certain speed. , a swirling low-temperature gas film is formed in the mixing part near the wall area, and the low-temperature gas swirls forward in the mixing part, wrapping the high-temperature furnace smoke from the furnace in the central area of the mixing part, avoiding the high-temperature furnace smoke directly scouring the wall surface of the mixing part , which fundamentally solves the problem of coking in the mixing part, and because the low-temperature gas entering the mixing part conducts heat transfer and mixing with the high-temperature furnace smoke in the center of the mixing part when the swirling flow advances, and gradually achieves a uniform mixing determined by heat balance. Temperature, the flow organization method that makes the cold and hot air mix and transfer heat in the area far from the wall, not only solves the problem of coking in the mixing chamber, but also solves the problem of cracking in the mixing chamber caused by uneven heating of the wall; in addition, A small part of the low-temperature gas entering the mixing part tangentially from the volute of the inlet connection part diffuses into the furnace from the swirl flow of the furnace smoke opening, and a low-temperature swirl gas film is also formed on the wall area of the furnace smoke opening, which avoids the direct flow of high-temperature furnace smoke. The wall surface at the smoke opening of the furnace is washed, thereby solving the problem of coking at the smoke opening of the furnace.
[0045] According to the lignite boiler provided by this embodiment, since it includes the above-mentioned volute inlet furnace smoke mixing chamber, the problems of coking and cracking in the mixing part and the problem of coking in the smoke port of the furnace are also solved.
