CN117515578A - Fuel preheating combustion system - Google Patents

Abstract

The invention discloses a fuel preheating combustion system. The fuel preheating combustion system comprises a material conveying device for conveying fuel; the preheating furnace is communicated with the material conveying device and is used for preheating fuel; the combustion furnace is communicated with the preheating furnace and is used for receiving and combusting fuel output by the preheating furnace; a boiler communicated with a flue gas outlet of the combustion furnace; the multi-stage air distribution device comprises an air preheater which is communicated with a flue gas outlet of the boiler and can be communicated with air, a plurality of air distribution pipelines which are communicated with the air preheater and the combustion furnace, the air distribution pipelines are uniformly distributed along the length direction of the combustion furnace, and each air distribution pipeline is provided with an air path control valve. The fuel preheating combustion system provided by the invention not only realizes low-volatile low-calorific-value fuelThe large-scale digestion is realized, the recycling of the energy of the high-temperature flue gas is realized, the energy is saved, the environmental pollution is reduced, and meanwhile, the low NO is realized through the multi-stage air distribution device _X And (3) burning.

Description

A fuel preheating combustion system

Technical field

The present invention relates to the technical field of fuel combustion, and in particular to a fuel preheating combustion system.

Background technique

The gasified fine slag produced by the coal gasification process has a large loss on ignition and does not meet the standards for building blending raw materials. It is difficult to be directly used in construction projects and road projects, resulting in the lack of effective large-scale consumption methods for gasified fine slag; The large-scale production of slag causes serious waste of resources and occupies a large amount of land resources. The dust causes air pollution, and the leachate after long-term storage or landfill can also cause soil and water pollution.

In the existing technology, coal-based low-volatility and low-calorific-value fuels are usually burned in boilers through low-proportion blending and then reused; alternatively, carbon powder obtained through flotation decarburization can be directly used in combustion equipment. fuel. When processed through low-proportion blending, due to the high water content of some coal-based low-volatile and low-calorific value fuels, which require a large amount of processing, long-term continuous blending will reduce the stability of the boiler system and have a negative impact on the boiler combustion efficiency. , which is not conducive to the large-scale consumption of coal-based low-volatility and low-calorific-value fuels; the flotation decarburization method increases the mixing ratio compared to the direct mixing method, which plays an optimization role in the mixing, and the obtained ash powder can be used for Building materials and road and bridge projects have realized the hierarchical and high-value utilization of coal-based low-volatility and low-calorific value fuels. However, the high cost of equipment, flotation reagents, labor costs, etc. in the flotation process also makes flotation decarbonization difficult. Achieve large-scale consumption of coal-based low-volatility and low-calorific-value fuels.

Therefore, how to realize large-scale consumption of low-volatility and low-calorific value fuels is a technical problem that those skilled in the art currently need to solve.

Contents of the invention

In view of this, the object of the present invention is to provide a fuel preheating combustion system to achieve large-scale consumption of low-volatility and low-calorific value fuels.

In order to achieve the above objects, the present invention provides the following technical solutions:

A fuel preheating combustion system, including:

Conveying device for conveying fuel;

A preheating furnace connected to the material conveying device for preheating fuel;

a combustion furnace communicated with the preheating furnace, used to receive and burn the fuel output by the preheating furnace;

A boiler connected to the flue gas outlet of the combustion furnace, the boiler being provided with a cavity for containing liquid medium;

A multi-stage air distribution device, which includes an air preheater connected to the flue gas outlet of the boiler and capable of communicating with the air, and a plurality of air preheaters connected to the combustion furnace. Air distribution pipeline, a plurality of the air distribution pipelines are evenly distributed along the length direction of the combustion furnace, and each of the air distribution pipelines is provided with an air path control valve.

Preferably, in the above fuel preheating combustion system, the flue gas outlet of the air preheater is connected with the preheating furnace.

Preferably, the above-mentioned fuel preheating combustion system also includes a central controller, an outlet fuel temperature controller provided in the preheating furnace, and a temperature controller along the path provided in the combustion furnace. The outlet The fuel temperature controller, the process temperature controller and the multi-stage air distribution device are all electrically connected to the central controller.

Preferably, the above-mentioned fuel preheating combustion system also includes a flue gas online monitoring device provided at the end of the combustion furnace, and the flue gas online monitoring device and the feeding device are both electrically connected to the central controller. connect.

Preferably, the above-mentioned fuel preheating combustion system also includes an outlet flue gas pipeline connected to the preheating furnace, an induced draft fan provided in the outlet flue gas pipeline, and an induced draft fan connected to the outlet flue gas pipeline. chimney.

Preferably, the above fuel preheating combustion system also includes a flue gas recirculation pipeline, the flue gas recirculation pipeline communicates with the outlet flue gas pipeline and the air preheater, and the flue gas The recirculation pipeline is equipped with an opening control valve.

Preferably, in the above fuel preheating combustion system, the multi-stage air distribution device further includes an air blower for supplying air to the air preheater.

Preferably, in the above-mentioned fuel preheating combustion system, the combustion furnace is a rotary kiln structure inclined to the horizontal plane, and one end of the combustion furnace close to the preheating furnace is higher than the combustion furnace and away from the preheating furnace. one end.

Preferably, in the above fuel preheating combustion system, the preheating furnace is a horizontal rotary kiln structure, and the inner wall of the preheating furnace is provided with inner spiral blades and a partition connecting the inner spiral blades.

Preferably, in the above-mentioned fuel preheating combustion system, the number of the air distribution ducts is three, which are the first air distribution duct, the second air distribution duct and the third air distribution duct, and the third air distribution duct is One air distribution duct is provided with a primary air path valve, the second air distribution duct is provided with a secondary air path valve, and the third air distribution duct is provided with a third level air path valve.

When using the fuel preheating combustion system provided by the present invention, low volatile and low calorific value fuel is input into the preheating furnace through a feeding device, and the low volatile and low calorific value fuel is preheated through the preheating furnace, and then the low volatile and low calorific value fuel is The low calorific value fuel enters the combustion furnace and is fully burned in the combustion furnace to achieve large-scale consumption of low volatile and low calorific value fuel. Since the flue gas outlet of the boiler is connected with the combustion furnace, the ultra-high temperature flue gas discharged from the combustion furnace is connected with the combustion furnace. The heat exchange of the liquid medium in the boiler enables the liquid medium to generate high-temperature steam to achieve energy output and realize the waste heat utilization of ultra-high-temperature flue gas, which not only saves energy but also reduces environmental pollution; in addition, due to the air in the multi-stage distribution device The preheater is connected to the flue gas outlet of the boiler and can be conducted with the air. Multiple air distribution pipelines connect the air preheater and the combustion furnace. Therefore, when the air preheater is connected with the air, the flue gas from the boiler is The high-temperature flue gas discharged from the outlet enters the air preheater, and the air in the air preheater is preheated by the high-temperature flue gas. The preheated air enters the combustion furnace through multiple air distribution ducts, further realizing the control of high-temperature flue gas. The recycling of air saves energy and reduces pollution; because multiple air distribution ducts are evenly distributed along the length of the burner, the preheated air can be distributed along the length of the burner through multiple air distribution ducts To achieve multi-level air distribution for the combustion furnace, since each air distribution pipe is equipped with an air path control valve, the air volume of each air distribution duct can be adjusted through each air path control valve. The air volume of the air path is adjusted so that the main combustion zone at the front end of the burner has a reducing atmosphere to achieve low _NOx combustion. It can be seen that the fuel preheating combustion system provided by the present invention not only realizes the large-scale consumption of low-volatility and low-calorific value fuels, but also realizes the recycling of high-temperature flue gas energy, saving energy and reducing environmental pollution. , low _NOx combustion is achieved through multi-stage air distribution device.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of a fuel preheating combustion system provided by an embodiment of the present invention;

Figure 2 is a schematic structural diagram of another fuel preheating combustion system provided by an embodiment of the present invention.

Among them, 100 is the material conveying device, 200 is the preheating furnace, 201 is the outlet flue gas pipeline, 202 is the induced draft fan, 203 is the chimney, 300 is the combustion furnace, 400 is the boiler, 500 is the multi-stage air distribution device, and 501 is Air preheater, 502 is the air distribution pipe, 5021 is the first air distribution pipe, 5022 is the second air distribution pipe, 5023 is the third air distribution pipe, 503 is the air blower, and 600 is the flue gas online monitoring device , 700 is the flue gas recirculation pipeline.

Detailed ways

In view of this, the core of the present invention is to provide a fuel preheating combustion system to achieve large-scale consumption of low-volatility and low-calorific value fuels.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

As shown in Figures 1 to 2, an embodiment of the present invention discloses a fuel preheating combustion system, which includes a feeding device 100, a preheating furnace 200, a combustion furnace 300, a boiler 400 and a multi-stage air distribution device 500.

Among them, the feeding device 100 is used to transport fuel; the preheating furnace 200 is connected with the feeding device 100 and used to preheat the fuel; the combustion furnace 300 is connected with the preheating furnace 200 and is used to receive and burn the fuel output by the preheating furnace 200. ; The boiler 400 is connected with the flue gas outlet of the combustion furnace 300, and the boiler 400 is provided with a cavity for holding liquid medium; the multi-stage air distribution device 500 includes an air preheater that is connected with the flue gas outlet of the boiler 400 and can be communicated with the air. The air preheater 501 and a plurality of air distribution ducts 502 connect the air preheater 501 and the combustion furnace 300. The plurality of air distribution ducts 502 are evenly distributed along the length direction of the combustion furnace 300. Each air distribution duct 502 is provided with an air line control valve.

When using the fuel preheating combustion system provided by the present invention, low volatile and low calorific value fuel is input into the preheating furnace 200 through the feeding device 100, and the low volatile and low calorific value fuel is preheated through the preheating furnace 200, and then The low-volatility and low-calorific-value fuel enters the combustion furnace 300 and is fully burned in the combustion furnace 300 to achieve large-scale consumption of low-volatility and low-calorific-value fuels; since the boiler 400 is connected to the flue gas outlet of the combustion furnace 300, the combustion furnace The ultra-high temperature flue gas discharged from 300 exchanges heat with the liquid medium in the boiler 400 (the liquid medium is water in this embodiment), causing the liquid medium to generate high-temperature steam to achieve energy output, realizing the waste heat utilization of the ultra-high temperature flue gas, which not only saves Energy is saved and environmental pollution is reduced; in addition, since the air preheater 501 of the multi-stage distribution device is connected to the flue gas outlet of the boiler 400 and can be communicated with the air, multiple air distribution pipelines 502 are connected to the air preheater 501 and the combustion furnace 300. Therefore, when the air preheater 501 is connected to the air, the high-temperature flue gas discharged from the flue gas outlet of the boiler 400 enters the air preheater 501, and passes through the high-temperature flue gas to the air preheater 501. The air is preheated, and the preheated air enters the combustion furnace 300 through multiple air distribution ducts 502, further realizing the recycling of high-temperature flue gas, saving energy, and reducing pollution; due to multiple air distribution ducts 502 is evenly distributed along the length direction of the combustion furnace 300. Therefore, the preheated air can be distributed to the combustion furnace 300 along the length direction of the combustion furnace 300 through multiple air distribution pipelines 502 to achieve multi-level air distribution. Since each air distribution pipeline The pipelines 502 are all provided with air duct control valves. Therefore, the air volume of each air distribution duct can be adjusted through each air duct control valve. By adjusting the air volume of each air distribution duct 502, the main combustion area at the front end of the combustion furnace 300 can be adjusted. It is a reducing atmosphere to achieve low _NOx combustion. It can be seen that the fuel preheating combustion system provided by the present invention not only realizes the large-scale consumption of low-volatility and low-calorific value fuels, but also realizes the recycling of high-temperature flue gas energy, saving energy and reducing environmental pollution. , low _NOx combustion is achieved through multi-stage air distribution device.

It should be understood that the preheating furnace 200 can be placed directly below the outlet of the feeding device 100, so that the fuel enters the preheating furnace 200 from the outlet of the feeding device 100 under the action of its own weight, or the fuel can be transported through an additional transmission mechanism. to the preheating furnace 200, as long as it can meet the usage requirements; similarly, the combustion furnace 300 can be set directly below the preheating furnace 200, so that the preheated fuel enters the combustion furnace 300 under the action of its own weight, or it can also be installed through another The transmission mechanism is provided to transport the fuel to the combustion furnace 300, as long as it can meet the usage requirements; optionally, the preheating furnace 200 provided by the embodiment of the present invention is directly provided below the outlet of the feeding device 100, and is A hopper is set between the charging device 100 and the preheating furnace 200, so that the fuel enters the preheating furnace 200 through the hopper under the action of its own weight, reducing the spillage of fuel; the combustion furnace 300 is directly placed below the preheating furnace 200, and passes through the corresponding The ground pipeline connects the preheating furnace 200 and the combustion furnace 300, so that the fuel enters the combustion furnace 300 from the preheating furnace 200 through the pipeline under the action of its own weight, and the fuel is burned in the combustion furnace 300.

Further, the flue gas outlet of the air preheater 501 is connected to the preheating furnace 200, so that the air can be fully preheated by high-temperature flue gas in the air preheater 501, and the high-temperature flue gas that completes the heat exchange is preheated by the air. The flue gas is discharged from the outlet of the reactor 501 and then enters the preheating furnace 200 to fully preheat the fuel in the preheating furnace 200 and improve the utilization rate of the output calorific value of the low volatile and low calorific value fuel.

In addition, the fuel preheating combustion system also includes a central controller, an outlet fuel temperature controller installed in the preheating furnace 200 and a process temperature controller installed in the combustion furnace 300. The outlet fuel temperature controller, the process temperature controller The controller and the multi-stage air distribution device 500 are electrically connected to the central controller, so as to detect the fuel temperature at the outlet of the preheating furnace 200 through the outlet fuel temperature controller, and to detect the temperature along the combustion furnace 300 through the along-process temperature controller. , after the central controller receives the fuel temperature information at the outlet of the preheating furnace 200 and the temperature information along the combustion furnace 300, it automatically regulates the opening of the air path control valve of each air distribution pipeline 502 of the multi-stage air distribution device 500. , thereby adjusting the air volume of each air distribution pipe 502, so that the combustion furnace 300 can achieve isothermal combustion throughout the entire process.

Furthermore, the fuel preheating combustion system also includes a flue gas online monitoring device 600 provided at the end of the combustion furnace 300. The flue gas online monitoring device 600 and the feeding device 100 are both electrically connected to the central controller to pass the flue gas online. The monitoring device 600 performs real-time detection of O ₂ , CO, NO _x and other components in the ultra-high temperature flue gas near the outlet of the combustion furnace 300 , and feeds the detection results back to the central controller, which uses the detection results to Based on the results and the fuel temperature information at the outlet of the preheating furnace 200 and the temperature information along the way in the combustion furnace 300, the fuel input volume of the feeding device 100 and the air supply volume of the multi-stage air distribution device 500 are adjusted in time to preheat the fuel. The large-scale and stable operation of the combustion system is further regulated, thereby realizing the system's large-scale and stable consumption of coal-based low-volatility and low-calorific-value fuels, full-process isothermal low-NOx smart combustion, and full utilization of the energy of low-volatility and low-calorific value fuels.

As shown in Figure 1, the fuel preheating combustion system also includes an outlet flue gas pipeline 201 connected to the preheating furnace 200, an induced draft fan 202 provided in the outlet flue gas pipeline 201, and an induced draft fan 202 connected to the outlet flue gas pipeline 201. The chimney 203 is so that under the action of the induced draft fan 202, the flue gas discharged from the preheating furnace 200 enters the chimney 203 through the outlet flue gas pipeline 201 and is discharged from the chimney 203.

As shown in Figure 2, in a specific embodiment of the present invention, the fuel preheating combustion system also includes a flue gas recirculation pipeline 700. The flue gas recirculation pipeline 700 connects the outlet flue gas pipeline 201 and the air preheating 501, and the flue gas recirculation pipeline 700 is provided with an opening control valve to introduce part of the flue gas in the outlet flue gas pipeline 201 into the air preheater 501, and control it to enter the air preheater through the opening control valve 501 flue gas volume, achieving proportional control of air and flue gas.

In addition, the above-mentioned opening control valve can also be electrically connected to the central controller, so that the central controller can automatically regulate the opening of the opening control valve according to the temperature feedback along the way in the combustion furnace 300, and further regulate the preheating combustion of the fuel. The system operates stably at scale.

The multi-stage air distribution device 500 provided by the present invention also includes an air blower 503 to supply air to the air preheater 501 through the air blower 503. The above-mentioned opening control valve is provided at the connection between the flue gas recirculation pipeline 700 and the air blower 503. , to control the ratio of air and flue gas entering the blower 503 through the opening control valve.

It should be noted that the above-mentioned combustion furnace 300 can be a rotary furnace structure, a fluidized bed incinerator structure or a mechanical grate furnace structure. As long as the structure can meet the usage requirements, it falls within the protection scope of the present invention; optionally, The combustion furnace 300 provided by the embodiment of the present invention is a rotary kiln structure that is inclined to the horizontal plane, and the end of the combustion furnace 300 close to the preheating furnace 200 is higher than the end of the combustion furnace 300 far away from the preheating furnace 200, so that the fuel can move under its own weight. The bottom slides from the end close to the preheating furnace 200 to the end far away from the preheating furnace 200, which avoids the installation of an additional material pushing mechanism in the combustion furnace 300, reduces the number of parts, and reduces the cost.

It should be understood that the present invention does not specifically limit the inclination degree of the above-mentioned combustion furnace 300. The inclination degree of the above-mentioned fuel furnace 300 can be adjusted adaptively according to the type, particle size and processing capacity of the fuel, as long as the inclination degree can meet the usage requirements. It falls within the protection scope of the present invention; optionally, the inclination angle between the combustion furnace 300 and the horizontal plane provided in the embodiment of the present invention is 5°.

The preheating furnace 200 provided by the present invention has a horizontal rotary kiln structure, and the inner wall of the preheating furnace 200 is provided with inner spiral blades and a partition connecting the inner spiral blades, so that the fuel can be pushed through the inner spiral blades through the partition. Throwing disturbed fuel achieves efficient heat exchange between fuel and high-temperature flue gas and improves fuel preheating efficiency.

In addition, the present invention does not specifically limit the number of air distribution pipelines 502, as long as the number can meet the usage requirements, it falls within the protection scope of the present invention; optionally, as shown in Figures 1 and 2, the embodiments of the present invention include The number of air distribution pipelines 502 provided is three, which are the first air distribution pipeline 5021, the second air distribution pipeline 5022 and the third air distribution pipeline 5023. The first air distribution pipeline 5021 is provided with a first-level air distribution pipeline. The second air distribution duct 5022 is provided with a secondary air duct valve, and the third air distribution duct is provided with a third-level air duct valve to control the air inlet volume in the first air distribution duct through the primary air duct valve. The first-stage air duct valve controls the air inlet volume in the second air distribution duct, and the third-stage air duct valve controls the air inlet volume in the third air distribution duct, thereby through the first air distribution duct 5021, the second air distribution duct 5022 and the third air distribution duct. The air distribution pipeline 5023 reasonably distributes the high-temperature air in the air preheater 501 and sends it to the combustion furnace 300, so that the low-volatility and low-calorific-value fuel can be stably and fully burned in the combustion furnace 300 to achieve the scale of low-volatility and low-calorific value fuel. Continuous and stable processing solves the technical problem of large-scale and stable processing of low-volatility and low-calorific value fuels with existing technology. At the same time, the air volume is reasonably distributed and sent to the combustion furnace in multiple stages to ensure that the main combustion zone in the front section of the combustion furnace is a reducing atmosphere, without the need for Low _NOx combustion can be achieved by adding a flue gas treatment device, saving equipment investment costs.

The terms “first” and “second” in the description and claims of the present invention and the above-mentioned drawings are used to distinguish different objects, rather than describing a specific sequence. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not configured with the listed steps or units, but may include steps or units that are not listed.

The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be practiced in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A fuel-preheating combustion system, characterized by comprising:

the material conveying device is used for conveying fuel;

the preheating furnace is communicated with the material conveying device and is used for preheating fuel;

the combustion furnace is communicated with the preheating furnace and is used for receiving and combusting fuel output by the preheating furnace;

the boiler is communicated with the flue gas outlet of the combustion furnace and is provided with a cavity for containing liquid medium;

the multistage air distribution device comprises an air preheater which is communicated with a flue gas outlet of the boiler and can be communicated with air, and a plurality of air distribution pipelines which are communicated with the air preheater and the combustion furnace, wherein the air distribution pipelines are uniformly distributed along the length direction of the combustion furnace, and each air distribution pipeline is provided with an air path control valve.

2. The fuel-preheating combustion system according to claim 1, wherein the flue gas outlet of the air preheater communicates with the preheating furnace.

3. The fuel preheating combustion system according to claim 1, further comprising a central controller, an outlet fuel temperature controller disposed in the preheating furnace and an edge temperature controller disposed in the combustion furnace, wherein the outlet fuel temperature controller, the edge Cheng Wenkong and the multi-stage air distribution device are all electrically connected with the central controller.

4. The fuel-preheating combustion system according to claim 3, further comprising an on-line flue gas monitoring device disposed at the end of the burner, wherein the on-line flue gas monitoring device and the material delivery device are electrically connected to the central controller.

5. The fuel-preheating combustion system according to claim 1, further comprising an outlet flue gas duct in communication with the preheating furnace, an induced draft fan disposed in the outlet flue gas duct, and a chimney in communication with the outlet flue gas duct.

6. The fuel-preheating combustion system according to claim 5, further comprising a flue gas recirculation line that communicates the outlet flue gas line and the air preheater, and the flue gas recirculation line is provided with an opening control valve.

7. The fuel-preheating combustion system according to claim 1, wherein the multi-stage air distribution device further comprises a blower for blowing air to the air preheater.

8. The fuel preheating combustion system according to claim 1, wherein the combustion furnace is of a rotary kiln structure inclined to a horizontal plane, and an end of the combustion furnace near the preheating furnace is higher than an end of the combustion furnace far from the preheating furnace.

9. The fuel preheating combustion system according to claim 1, wherein the preheating furnace is of a rotary kiln structure which is horizontally arranged, and an inner wall of the preheating furnace is provided with an inner spiral blade and a partition plate which is connected with the inner spiral blade.

10. The fuel-preheating combustion system according to claim 1, wherein the number of the air distribution pipelines is three, namely a first air distribution pipeline, a second air distribution pipeline and a third air distribution pipeline, the first air distribution pipeline is provided with a primary air passage valve, the second air distribution pipeline is provided with a secondary air passage valve, and the third air distribution pipeline is provided with a tertiary air passage valve.