CN215294990U

CN215294990U - Boiler hot air circulating system

Info

Publication number: CN215294990U
Application number: CN202121411176.8U
Authority: CN
Inventors: 赵栓柱; 张晓敏; 边晓东; 许龙
Original assignee: Chinacoal Erdos Energy Chemical Co ltd
Current assignee: Chinacoal Erdos Energy Chemical Co ltd
Priority date: 2021-06-23
Filing date: 2021-06-23
Publication date: 2021-12-24
Anticipated expiration: 2031-06-23

Abstract

The utility model discloses a boiler hot air circulating system, which comprises a boiler, a coal mill, an air supply pre-heater, a primary air pre-heater, an air feeder and a primary fan; an air supply drainage port is arranged on a pipeline at the air outlet of the air supply air preheater and is communicated with an air inlet of the air feeder through the pipeline; a primary air drainage port is formed in a pipeline at an air outlet of the primary air pre-heater and is communicated with an air inlet of a primary fan through a pipeline. Has the advantages that: the temperature of the air inlets of the primary fan and the air feeder is maintained above 20 ℃ by controlling the hot air quantity introduced into the primary fan and the air feeder, the smoke exhaust temperature of the boiler is not lower than the dew point temperature of smoke, the problem of blockage of an air preheater is effectively relieved, the frequency of starting and shutting down the boiler and cleaning ash can be reduced, the operation and maintenance cost is reduced, and the economic benefit of an enterprise is improved.

Description

Boiler hot air circulating system

The technical field is as follows:

the utility model relates to a hot air circulating system especially relates to a boiler hot air circulating system.

Background art:

in order to improve the heat exchange performance of the boiler, the flue gas in the tail flue of the boiler is preheated to a certain temperature by the air preheater before entering the boiler, so that the energy consumption of the boiler is reduced. However, in winter in northern areas, the environmental temperature is relatively low, the temperature can be lowered to below minus 25 ℃ in extreme weather in winter, and in addition, the air suction inlet of the fan matched with the boiler is arranged outdoors, although the air heater heating device is designed at the air inlet of the fan, because the air heater is a steam heating heat exchanger, internal tubes are easy to leak due to welding quality or abrasion and are not easy to process in operation, the air heater is not leaked for a long time and is forced to be completely isolated, the air temperature at the air inlet of the fan is too low, when cold air exchanges heat with flue gas through an air preheater, the temperature difference is too large, the temperature of the side tube wall of the flue gas is too low, particularly when the boiler operates at low load, the temperature of the flue gas is lower than the dew point temperature of the flue gas, so that water vapor in the flue gas is condensed, the flue gas is gradually accumulated, the tube bundle of the air preheater of the boiler is blocked, the resistance of the flue gas flowing through the air preheater is increased, The induced draft fan output is abnormally increased, the exhaust smoke temperature is abnormally increased, and finally the vehicle is forced to stop.

In addition, because the boiler design checks that the total moisture of the coal is 12.43%, but the total moisture of the coal actually entering the boiler is mostly more than 16%, the higher the moisture in the coal is, the lower the boiler exhaust gas temperature is correspondingly, and the probability of pipe blockage at the flue gas side of the air preheater pipe bundle is also increased.

The utility model has the following contents:

an object of the utility model is to provide a boiler hot air circulating system.

The utility model discloses by following technical scheme implement:

the boiler hot air circulating system comprises a boiler, a coal mill, an air supply pre-heater, a primary air pre-heater, an air feeder and a primary fan;

the discharge hole of the coal mill is communicated with the feed hole of the burner of the boiler through a pipeline, and the air supply air preheater and the primary air preheater are sequentially arranged in the flue of the boiler along the direction of the smoke trend;

the air inlet of the air feeder is communicated with the atmosphere, the air outlet of the air feeder is communicated with the air inlet of the air supply air preheater, and the air outlet of the air supply air preheater is communicated with the air inlet of the combustor; an air supply drainage port is formed in a pipeline at the air outlet of the air supply air preheater and is communicated with an air inlet of the air feeder through a pipeline;

the air inlet of the primary air fan is communicated with the atmosphere, the air outlet of the primary air fan is communicated with the air inlet of the primary air preheater, and the air outlet of the primary air preheater is communicated with the air inlet of the coal mill; a primary air drainage port is formed in a pipeline at the air outlet of the primary air pre-heater and is communicated with an air inlet of the primary fan through a pipeline;

the air supply drainage port and the primary air drainage port are both rotatably provided with a hot air recirculation baffle, and the air inlet of the air feeder and the air inlet of the primary air fan are both provided with temperature sensors.

Furthermore, a platen superheater, a high-temperature superheater, a low-temperature superheater and an economizer are sequentially arranged in the flue of the boiler at the upstream of the air supply air preheater along the direction of the smoke trend.

Further, a denitration reactor is arranged in a flue of the boiler between the economizer and the air supply air preheater.

The utility model has the advantages that:

the primary air drainage port and the air supply drainage port are arranged, the preheated partial primary air and secondary air are respectively led to the air inlets of the corresponding primary air fan and the corresponding air feeder through the pipelines, the hot air quantity for leading in the primary air fan and the air feeder is controlled by controlling the opening degree of the corresponding hot air recirculation baffle, the temperature of the air inlets of the primary air fan and the air feeder is further ensured to be maintained above 20 ℃, the smoke exhaust temperature of the boiler is not lower than the smoke dew point temperature, the problem of blockage of an air preheater is effectively relieved, the boiler can still run stably for a long period in a cold environment, the boiler is not influenced by the external environment temperature and the boiler, the frequency of starting and stopping the boiler and cleaning the ash is reduced, the operation and maintenance cost is reduced, and the economic benefit of enterprises is improved.

Description of the drawings:

in order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic system diagram of the present embodiment.

In the figure: the system comprises a boiler 1, a coal mill 2, an air supply air preheater 3, a primary air preheater 4, an air supply 5, a primary fan 6, an economizer 7, a denitration reactor 8, a hot air recirculation baffle 9, a temperature sensor 10, a screen superheater 11, a high-temperature superheater 12 and a low-temperature superheater 13.

The specific implementation mode is as follows:

the technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Example 1:

the hot air circulation system of the boiler shown in fig. 1 comprises a boiler 1, a coal mill 2, an air supply preheater 3, a primary air preheater 4, a blower 5 and a primary fan 6;

a discharge port of the coal mill 2 is communicated with a feed port of a combustor of the boiler 1 through a pipeline, and a platen superheater 11, a high-temperature superheater 12, a low-temperature superheater 13, an economizer 7, a denitration reactor 8, an air supply air preheater 3 and a primary air preheater 4 are sequentially arranged in a flue of the boiler 1 along the direction of the smoke trend;

an air inlet of the air feeder 5 is communicated with the atmosphere, an air outlet of the air feeder 5 is communicated with an air inlet of the air feeding air preheater 3, and an air outlet of the air feeding air preheater 3 is communicated with an air inlet of the combustor; an air supply drainage port is arranged on a pipeline at the air outlet of the air supply air preheater 3 and is communicated with an air inlet of the air feeder 5 through a pipeline;

an air inlet of the primary air fan 6 is communicated with the atmosphere, an air outlet of the primary air fan 6 is communicated with an air inlet of the primary air preheater 4, and an air outlet of the primary air preheater 4 is communicated with an air inlet of the coal mill 2; a primary air drainage port is arranged on a pipeline at the air outlet of the primary air pre-heater 4 and is communicated with an air inlet of a primary fan 6 through a pipeline;

the hot air recirculation baffle 9 is rotatably arranged at the air supply drainage port and the primary air drainage port, and the temperature sensors 10 are arranged at the air inlet of the air feeder 5 and the air inlet of the primary air fan 6.

The working principle is as follows:

the coal from the coal yard is stored in a coal bunker and sent into a coal mill 2 through a coal feeder, and the ground coal powder is carried by hot air exhausted by a primary fan 6 and then sent into a hearth of a boiler 1 through a burner for combustion. After high-temperature flue gas carrying fly ash generated by combustion in a furnace radiates and releases heat on a water-cooled wall in a hearth, the high-temperature flue gas sequentially flows through a screen superheater 11, a high-temperature superheater 12, a low-temperature superheater 13 and an economizer 7, exchanges heat with working media in heated surfaces, removes nitrogen oxides contained in the flue gas through a denitration reactor 8, exchanges heat with primary air and secondary air through an air supply air preheater 3 and a primary air preheater 4, removes the fly ash through a subsequent dust remover, removes sulfur oxide contained in the flue gas through a desulfurization device, and finally discharges the flue gas into a chimney. The primary air is pressed into the primary air preheater by the primary fan 6, and hot air from the primary air preheater directly enters the coal mill 2, is dried and carries pulverized coal to be sent into a hearth; the secondary air is pressed into the secondary air preheater by the blower 5 and is directly sent into the hearth by the burner.

In this embodiment, through offering primary air drainage mouth and air supply drainage mouth, and lead the part primary air and overgrate air after preheating to the air intake department of corresponding primary air fan 6 and forced draught blower 5 respectively through the pipeline, and through the aperture size of control hot air recirculation baffle 9 that corresponds, control the hot blast volume of leading in primary air fan 6 and forced draught blower 5, and then guarantee that the temperature of the air intake department of primary air fan 6 and forced draught blower 5 all maintains more than 20 ℃, guarantee that boiler 1 exhaust gas temperature is not less than flue gas dew point temperature under any circumstance, with thoroughly solving boiler 1 air heater jam condition, through this embodiment, effectively alleviated the air blockage problem, guarantee that boiler 1 still can long period steady operation under cold environment, the frequency of starting and shutting down the stove, deashing.

According to the operation condition of the boiler 1 in winter in 2020, 1 time of furnace shutdown and ash removal operation is required to be carried out on the boiler 1 in 30 days, the fuel oil cost for starting and stopping the boiler each time is about 43.2 ten thousand yuan, the ash removal cost is about 8 ten thousand yuan, the 2 boilers 1 are calculated, and the boiler needs to be started and stopped for 6 times and ash removal for 6 times in winter, so that the capital can be saved by about 43.8 multiplied by 6+8 multiplied by 6 to 310.8 ten thousand yuan each year.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The hot air circulating system of the boiler is characterized by comprising a boiler, a coal mill, an air supply pre-heater, a primary air pre-heater, an air supply machine and a primary fan;

2. The boiler hot air circulation system according to claim 1, wherein a platen superheater, a high temperature superheater, a low temperature superheater and an economizer are provided in sequence in a flue of the boiler upstream of the supply air preheater along a direction of a flue gas flow.

3. The boiler hot air circulation system according to claim 2, wherein a denitration reactor is provided in a flue of the boiler between the economizer and the supply air preheater.