CN201255403Y - External bed high and low temperature feed back tube coal supply system - Google Patents

Abstract

The utility model discloses a coal feeding system of external-bed high-and-low temperature return tube; wherein, a coal inlet is arranged on the external-bed high-and-low temperature return tube of a circulating fluidized bed boiler. Before coming in a hearth, coal firstly mixes with circulating ash in the external-bed high-and-low temperature return tube and is preheated, and then comes in the hearth together with the high-and-low circulating ash. One coal feeder can supply coal for two coal chutes or a plurality of coal chutes. The coal feeding system of external-bed high-and-low temperature return tube and the coal feeding manner that one coal feeder can supply coal for two coal chutes or a plurality of coal chutes improves the distributing evenness of coal in the hearth, increase the diffusivity of coal in the hearth, effectively reduces the amount of the coal feeder, facilitates the reasonable layout of the coal feeding system, decrease the openings of water cooling wall of the hearth, lowers the manufacturing cost and reduces the leakage hazard rate of the hearth.

Description

External bed high and low temperature feed back pipe coal supply system

Technical field

The utility model relates to the large circulating fluidized bed boiler coal supply system, is specifically related to a kind of external bed high and low temperature feed back pipe coal supply system.

Background technology

The coal-fired particle diameter of CFBB mainly is distributed between 1～10mm, and there is the diffusion problem of bigger coal-fired particle in burner hearth inside in going into stove fuel and can only slipping into burner hearth from the side wall of burner hearth of boiler.Along with the increase of CFBB capacity, the corresponding increase of furnace cross-sectional area, coal-fired limited in the diffusivity of burner hearth inside, be unfavorable for the burning of fuel in burner hearth.In order to solve fuel diffusion problem in the Large-scale CFB boiler stove, need to increase the coal feeding hole number of boiler usually; But, increase the opening that boiler coal feeding mouth number often needs to increase burner hearth, and the furnace pressure of CFBB is higher relatively, the burner hearth opening too much causes the leakage problem of burner hearth easily.

The fire box temperature of CFBB is much lower with respect to coal-powder boiler, and the heat flow density of burner hearth inside is corresponding lower, and the layout of Large-scale CFB boiler stove internal heating surface is restricted.In order to address this problem, in the grey closed circuit of burner hearth outside, external bed is set usually, arrange that wherein a certain amount of heating surface is with the not enough problem of compensation stove internal heating surface layout.In addition, the flowing velocity of circulating ash is far below the movement of particles speed in the burner hearth in the external bed, and the heating surface wear problem in the external bed is not serious, has also also solved stove internal heating surface wear problems to a certain extent.The operation principle of external bed is: the high-temp circulating ash that separator separates is divided into two-way and returns burner hearth, one tunnel process high temperature returning charge chamber and high temperature recycling pipe directly return burner hearth, another road enters the Heat Room of arranging heating surface, become the low temperature circulating ash with arranging after wherein heating surface is finished heat exchange, return burner hearth by low temperature feed back pipe again.

After the capacity of boiler amplified, the cross-sectional area of boiler increased, in order to realize even coal supply, the also corresponding increase of the quantity of coal feeding hole, the quantity of required feeder increase generally speaking.And a feeder is given two or more coal spout coal supplies, has effectively reduced the quantity of the required feeder of boiler, helps the layout of coal supply system.

Summary of the invention

The purpose of this utility model is to provide a kind of even coal supply that can realize boiler simultaneously, and has reduced the external bed high and low temperature feed back pipe coal supply system of CFBB of the opening of furnace wall cooling.

For achieving the above object, the technical solution adopted in the utility model is: comprise burner hearth and the separator that is connected with burner hearth, the outlet of separator lower end is connected with standpipe, the outlet of standpipe is connected with the inlet of high temperature returning charge chamber, heat exchange bed respectively, the high temperature returning charge mouth of high temperature returning charge chamber is connected with the inlet of high temperature recycling pipe, the high temperature returning charge ash inlet of offering on the outlet of high temperature recycling pipe and the burner hearth is connected, and also is provided with the high temperature coal spout that is connected with feeder on high temperature recycling pipe and pipeline between high temperature returning charge ash enters the mouth; The outlet of heat exchange bed is connected with the inlet of low temperature returning charge chamber, the low temperature returning charge mouth of low temperature returning charge chamber is connected with low temperature feed back pipe, the low temperature returning charge ash inlet of offering on the outlet of low temperature feed back pipe and the burner hearth is connected, and also is provided with the low temperature coal spout that is connected with feeder on low temperature feed back pipe and pipeline between low temperature returning charge ash enters the mouth.

Also be provided with high temperature recycling tube swelling joint on the high temperature recycling pipe between high temperature returning charge chamber of the present utility model and the high temperature coal spout; Also be provided with the low temperature feed back pipe expansion joint on the low temperature feed back pipe between low temperature returning charge chamber and the low temperature coal spout; Also be furnished with heating surface in the heat exchange bed.

The utility model is provided with coal spout on the external height of bed, low temperature feed back pipe, by this coal supply system, coal supply is pre-mixed and obtains heating with external bed high and low temperature circulating ash before entering burner hearth, the flowability of coal supply improves, the diffusion property of coal supply in burner hearth improves, and makes coal supply being more evenly distributed in burner hearth inside; On the external height of bed, low temperature feed back pipe, coal feeding hole is set, with separately from the high temperature recycling pipe coal supply compare coal feeding hole quantity and double, the increase of burner hearth coal feeding hole quantity makes coal-fired being more evenly distributed in burner hearth inside; Reduce the quantity of feeder, be beneficial to the layout of coal supply system; On the external height of bed, low temperature feed back pipe, coal feeding hole is set, can effectively be reduced in the open amount of burner hearth side water wall, avoid on water-cooling wall adopting more complexity allow tubular construction, reduced the manufacturing cost and the operation troubles rate of boiler.

Description of drawings

Fig. 1 is an overall structure schematic diagram of the present utility model;

Fig. 2, Fig. 3 are the connected mode schematic diagram of the utility model coal spout and feeder;

System's connection diagram when Fig. 4 is applied to large circulating fluidized bed boiler for the utility model.

The specific embodiment

Below in conjunction with accompanying drawing structural principle of the present utility model and operation principle are described in further detail.

Referring to Fig. 1, Fig. 4, the utility model comprises burner hearth 1 and the separator 17 that is connected with burner hearth 1, be provided with the blower fan 23 that is connected with burner hearth in the lower end of burner hearth 1, the upper end exhanst gas outlet of separator 17 is connected with back-end ductwork by pipeline, the outlet of separator 17 lower ends is connected with standpipe 8, particle in the burner hearth 1 leaves burner hearth 1 with flue gas and enters separator 17, under gravity and inertia acting in conjunction, the realization particle separates with flue gas, the particle that separates flows downward through standpipe 8, flue gas flows to top and finally enters back-end ductwork 18, after heating surface 19 heat exchange of arranging wherein, flue-gas temperature reduces, through further purifying the back by boiler induced-draft fan 21, enter atmosphere through chimney 20.Be divided into two-way by the high-temp circulating ash of standpipe 8 and return burner hearth: i.e. the outlet of standpipe 8 is connected with high temperature returning charge chamber 7 and the inlet that is furnished with the heat exchange bed 9 of heating surface 10 respectively, the high temperature returning charge mouth 6 of high temperature returning charge chamber 7 is connected with the inlet of high temperature recycling pipe 4, the high temperature returning charge ash inlet of offering on the outlet of high temperature recycling pipe 4 and the burner hearth 12 is connected, high temperature recycling pipe 4 is provided with the high temperature coal spout 3 that is connected with feeder 22 with the pipeline that high temperature returning charge ash enters the mouth between 2, and the high temperature recycling pipe 4 between high temperature returning charge chamber 7 and the high temperature coal spout 3 is provided with high temperature recycling tube swelling joint 5; The part high-temp circulating ash enters high temperature returning charge chamber 7 from the bottom of standpipe 8, the high temperature returning charge ash inlet 2 that enters high temperature recycling pipe 4 and burner hearth 1 through high temperature returning charge chamber opening 6 returns burner hearth, on external height of bed temperature feed back pipe 4, expansion joint 5 is set, with the compensate for heat expansion imbalance problem.The outlet of heat exchange bed 9 is connected with the inlet of low temperature returning charge chamber 11, the low temperature returning charge mouth 12 of low temperature returning charge chamber 11 is connected with low temperature feed back pipe 14, the low temperature returning charge ash inlet of offering on the outlet of low temperature feed back pipe 14 and the burner hearth 1 16 is connected, on the pipeline between low temperature feed back pipe 14 and the grey inlet 2 of low temperature returning charge, also be provided with the low temperature coal spout 15 that is connected with feeder 22, also be provided with low temperature feed back pipe expansion joint 13 on the low temperature feed back pipe 14 between low temperature returning charge chamber 11 and the low temperature coal spout 15.High-temp circulating ash by standpipe 8 enters heat exchange bed 9, carry out heat exchange with arranging heating surface 10 wherein, the temperature of circulating ash reduces, and returns burner hearth through the grey inlet 16 of the low temperature returning charge of low temperature returning charge chamber 11, external bed low temperature returning charge mouth 12, low temperature feed back pipe 14, burner hearth 1.Expansion joint 13 is set, with the compensate for heat expansion imbalance problem on external bed low temperature feed back pipe 14.

Referring to Fig. 2,3, a feeder 22 of the present utility model can be given high temperature coal spout 3 coal supplies of two high temperature recycling pipes simultaneously, also can give low temperature coal spout 15 coal supplies of two low temperature feed back pipes, also can be to low temperature coal spout 15 coal supplies simultaneously of the high temperature coal spout 3 of high temperature recycling pipe and low temperature feed back pipe, can effectively reduce the quantity of feeder, be beneficial to the layout of coal supply system.

Claims (3)

1, a kind of external height of bed, low temperature feed back pipe coal supply system, comprise burner hearth (1) and the separator (17) that is connected with burner hearth (1), it is characterized in that: the outlet of separator (17) lower end is connected with standpipe (8), the outlet of standpipe (8) respectively with high temperature returning charge chamber (7), the inlet of heat exchange bed (9) is connected, the high temperature returning charge mouth (6) of high temperature returning charge chamber (7) is connected with the inlet of high temperature recycling pipe (4), the high temperature returning charge ash inlet of offering on the outlet of high temperature recycling pipe (4) and the burner hearth (1) (2) is connected, and also is provided with the high temperature coal spout (3) that is connected with feeder (22) on high temperature recycling pipe (4) and high temperature returning charge ash enter the mouth pipeline between (2); The outlet of heat exchange bed (9) is connected with the inlet of low temperature returning charge chamber (11), the low temperature returning charge mouth (12) of low temperature returning charge chamber (11) is connected with low temperature feed back pipe (14), the low temperature returning charge ash inlet of offering on the outlet of low temperature feed back pipe (14) and the burner hearth (1) (16) is connected, and also is provided with the low temperature coal spout (15) that is connected with feeder (22) on low temperature feed back pipe (14) and low temperature returning charge ash enter the mouth pipeline between (2).

2, external bed high and low temperature feed back pipe coal supply system according to claim 1 is characterized in that: also be provided with high temperature recycling tube swelling joint (5) on the high temperature recycling pipe (4) between said high temperature returning charge chamber (7) and the high temperature coal spout (3); Also be provided with low temperature feed back pipe expansion joint (13) on the low temperature feed back pipe (14) between low temperature returning charge chamber (11) and the low temperature coal spout (15).

3, external bed high and low temperature feed back pipe coal supply system according to claim 1 is characterized in that: also be furnished with heating surface (10) in the said heat exchange bed (9).

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