Fire banking device of large circulating fluidized bed boiler

Abstract

The utility model discloses a banking-up device of a large circulating fluidized bed boiler, and belongs to the field of boilers. The device comprises a biomass fuel bin, a separator, a tail flue and a chimney, the biomass fuel bin is connected with a fuel nozzle of the boiler; the top of the boiler is connected with the top of the separator, and the bottom is connected with the bottom of the separator through a bent pipeline; a gas outlet is formed in the top of the separator and communicated with a tail flue, the flue outlet is divided into two branch pipes, one branch pipe is connected with a chimney, the other branch pipe is connected with a flue gas recirculation pipeline, a flue gas recirculation fan is arranged on the flue gas recirculation pipeline, and a part of flue gas is sent to the bottom of a boiler hearth; and the other part of flue gas is sent to a boiler spreading air inlet through a flue gas recirculation air distribution valve. The biomass fuel nozzle is arranged, the spraying amount is larger than the powder coal spraying amount, and the banking fire time is prolonged; and a flue gas recirculation pipeline is combined, so that the oxygen content in the fire raising process is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to a fire pressing device of large circulating fluidized bed boiler belongs to boiler field. BACKGROUND

[0002] At present, the large circulating fluidized bed boiler has problems, and the fire pressing is limited by the low furnace bed temperature, low steam temperature and low superheat degree. At present, the methods to solve the low fire pressing bed temperature include increasing the bed material heat storage capacity or spraying pulverized coal during the fire pressing process. Using the method of increasing the bed material heat storage capacity requires the use of a large heat storage device, which has many safety problems and shortens the fire pressing time. When the method of spraying pulverized coal during the fire pressing process is adopted, by calculating the proportion of the unburned fuel of the bed material during the fire pressing, it is found that this method has the problems of easy coking, large CO generation, small coal powder spraying amount, explosion risk during spraying, unsuccessful fire raising, environmental pollution and difficult extension of the fire pressing time. SUMMARY

[0003] In order to overcome the above-mentioned defects, the utility model provides a fire pressing device of large circulating fluidized bed boiler.

[0004] The technical scheme adopted by the utility model is:

[0005] A fire pressing device of large circulating fluidized bed boiler, comprising a biomass fuel bin, a separator, a tail flue and a chimney; the biomass fuel bin is connected with a fuel injection port of the boiler; the top of the boiler is connected with the top of the separator, and the bottom is connected with the bottom of the separator through a curved pipeline; the top of the separator is provided with a gas outlet, which is communicated with the tail flue; the flue outlet is divided into two branch pipes, one branch pipe is connected with the chimney, and the other branch pipe is connected with a flue gas recirculation pipeline; a flue gas recirculation fan is arranged on the flue gas recirculation pipeline to send part of the flue gas to the bottom of the boiler furnace; the other part of the flue gas is sent to the boiler seeding air inlet through a flue gas recirculation air distribution valve.

[0006] A biomass fuel injection port is arranged at the lower part of the boiler furnace, and the biomass fuel injection port is connected with a screw feeder; seeding air is connected between the screw feeder and the biomass fuel injection port to uniformly spread the fuel.

[0007] The biomass fuel bin stores biomass block fuel, and the biomass fuel bin is connected with the screw feeder to control the feeding amount and feeding speed by the screw feeder.

[0008] The pulverized coal is prone to explosion due to the generation of CO, and cannot be sprayed in large quantities, so the utility model specially provides a biomass fuel injection port, and the biomass fuel can be continuously sprayed.

[0009] The flue gas recirculation pipeline is a structure in which flue gas is introduced back to the primary air and the secondary air by a recirculation fan.

[0010] The utility model discloses a biomass fuel, and the fuel in the biomass bunker is sprayed into the furnace through the biomass fuel nozzle under the action of the spreading wind, the feeding mode is strictly controlled, the explosion hidden danger is avoided, and the fire suppressing time is prolonged.

[0011] The utility model discloses a large -scale circulating fluidized bed boiler's fire suppressing device, the beneficial effect that brings has:

[0012] ① The utility model discloses the coal powder of prior art is replaced for biomass fuel, utilizes the advantage that biomass raw material is flammable, and the sulfur content is low, and the ignition point is low, and the ash content is low, and the pollutants (sulfur dioxide, nitrogen oxides etc.) produced when spraying the coal powder are reduced, and the CO generation amount is less.

[0013] ② The fire suppressing time is prolonged.

[0014] ③ Set up the biomass fuel nozzle, and the spraying amount is greater than the coal powder spraying amount, and the carbon monoxide accumulation explosion is not easy to occur, and the ash amount is small, and the primary air volume of the fire raising process does not need to be increased, and the bed temperature descending speed is slow, and the steam temperature and steam pressure descending speed are slow, and the pollutant generation amount is less.

[0015] ④ In the fire raising process, the original generation amount of the pollutant in the fire raising process can be reduced by combining the flue gas recirculation pipeline, and the oxygen amount in the fire raising process can be reduced.

[0016] The utility model will be further described below in connection with the drawings and examples. DRAWINGS

[0017] Figure 1 It is the structural schematic diagram of the utility model.

[0018] In the drawing: 1 is biomass bunker, 2 is screw feeder, 3 is spreading wind inlet, 4 is biomass fuel nozzle, 5 is boiler, 6 is separator, 7 is tail flue, 8 is chimney, 9 is flue gas recirculation fan, 10 is flue gas recirculation air volume distribution valve, 11 is flue gas recirculation pipeline. CONCRETE IMPLEMENTING METHOD

[0019] EXAMPLE

[0020] As Figure 1As shown, a large circulating fluidized bed boiler's fire suppression device, including biomass fuel bin 1, separator 6, tail flue 7 and chimney 8; biomass fuel bin 1 is connected with the fuel injection port of boiler 5; the top of boiler 5 is connected with the top of separator 6, and the bottom is connected with the bottom of separator through a curved pipeline; the top of separator 6 is provided with a gas outlet, which is communicated with tail flue 7, and the flue outlet is branched into two branches, one branch is connected with chimney 8, and the other branch is connected with flue gas recirculation pipeline 11, and flue gas recirculation fan 9 is arranged on flue gas recirculation pipeline 11, part of the flue gas is sent to the bottom of the furnace of boiler 5; the other part of the flue gas is sent to the boiler through flue gas recirculation air distribution valve 10.

[0021] A biomass fuel injection port 4 is arranged at the lower part of the furnace of boiler 5, and the biomass fuel injection port 4 is connected with a screw feeder 2, and the spreader air is connected between the screw feeder 2 and the biomass fuel injection port 4, so that the fuel can be uniformly spread.

[0022] The biomass fuel bin 1 stores biomass block fuel, and the biomass fuel bin 1 is connected with the screw feeder 2, so that the feeding amount and feeding speed of the fuel are controlled by the screw feeder 2.

[0023] The pulverized coal cannot be sprayed in a large amount because it is easy to explode due to the generation of CO, and therefore the biomass fuel injection port is specially arranged, and the biomass fuel can be continuously sprayed.

[0024] The flue gas recirculation pipeline 11 is a structure in which the flue gas is introduced back to the primary air and the secondary air by the recirculation fan. In the utility model, part of the flue gas is sent to the bottom of the furnace (primary air) by the flue gas recirculation fan 9, and the other part of the flue gas is sent to the biomass fuel injection port (spreader air) by the flue gas recirculation air distribution valve 10.

[0025] The utility model adopts biomass fuel, the fuel in the biomass bin is controlled by the screw feeder, and under the action of the spreader air, the fuel is sprayed into the furnace from the biomass fuel injection port, the feeding mode is strictly controlled, the explosion hazard is avoided, and the fire suppression time is prolonged; the flue gas recirculation pipeline at the bottom of the boiler returns part of the flue gas to the bottom of the boiler by adjusting the recirculation fan, and low-oxygen continuous small-scale combustion is realized.

[0026] The specific implementation method is as follows:

[0027] 1. After the boiler is normally fire suppressed, all the fans are stopped;

[0028] 2. According to the main steam temperature and pressure of the generator set, the biomass fire suppression device provided by the utility model is started;

[0029] (1) Open the biomass screw feeder sealing air (taken from compressed air);

[0030] (2) Start the induced draft fan to adjust the micro-negative pressure at the furnace outlet;

[0031] (3) Start the flue gas recirculation fan;

[0032] (4) Start the spreading air at the biomass fuel injection port;

[0033] (5) Start the biomass screw feeder and adjust the output according to the main steam temperature and the furnace temperature;

[0034] (6) After starting the biomass screw feeder, adjust the oxygen content at the outlet to be no less than 5%.

Claims

1. A device for reducing the temperature of the combustion gases in a large circulating fluidized bed boiler, characterized in that: The biomass fuel bin, the separator, the tail flue and the chimney are included; the biomass fuel bin is connected with the fuel injection port of the boiler; the top of the boiler is connected with the top of the separator, and the bottom is connected with the bottom of the separator through a curved pipeline; the top of the separator is provided with a gas outlet, which is communicated with the tail flue; the flue outlet is branched into two branches, one branch is connected with the chimney, and the other branch is connected with the flue gas recirculation pipeline; the flue gas recirculation fan is arranged on the flue gas recirculation pipeline to send part of the flue gas to the bottom of the boiler furnace; the other part of the flue gas is sent to the boiler through the flue gas recirculation air distribution valve.

2. A device for reducing the combustion in a large circulating fluidized bed boiler according to claim 1, characterized in that A biomass fuel injection port is arranged at the lower part of the boiler furnace, and the biomass fuel injection port is connected with the screw feeder; the air distribution is arranged between the screw feeder and the biomass fuel injection port.

3. A device for reducing the combustion in a large circulating fluidized bed boiler according to claim 1, characterized in that The biomass fuel bin is used for storing biomass block fuel, and the biomass fuel bin is connected with the screw feeder to control the biomass fuel feeding amount and feeding speed.

4. A device according to claim 1, c h a r a c t e r i s e d in that: The flue gas recirculation pipeline is used for guiding the flue gas to return to the primary air and the secondary air through the recirculation fan.

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