A flue gas blending treatment process and treatment equipment thereof

Abstract

The present invention provides a flue gas co-combustion treatment process and a treatment device thereof, the process comprising the following steps: S1: drawing out the carbon flue gas in the rotary kiln waste heat boiler and conveying the carbon flue gas to the flue gas main pipe; S2: letting the carbon flue gas enter the combustion system of the power plant boiler as part of the secondary air to form the flue gas after co-combustion; S3: the flue gas after co-combustion enters the flue gas treatment system of the power plant unit, and is discharged through the main chimney after being treated to meet the standard requirements. The process not only provides part of the secondary air for the power plant boiler, but also completes the treatment of the carbon flue gas, realizes the coordinated treatment of the flue gas of the carbon plant and the flue gas of the power plant, and treats the flue gas of the carbon plant together with that of the existing boiler, so that the original equipment can be used and the cost of new construction can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas co-combustion treatment, and in particular to a process for the coordinated co-combustion treatment of carbon flue gas and boiler flue gas. The present invention also relates to a treatment device that cooperates with the co-combustion treatment process. Background Art

[0002] In recent years, with the further tightening of air pollutant emission standards, ultra-clean emission transformation of large industrial flue gas such as coal-fired power plants has been implemented in coal-fired power plants in key areas. In order to further strengthen the comprehensive environmental governance work, continuously improve the living environment of the people, and promote the coordinated development of the economy and society, my country is gradually strengthening the daily supervision and management of coal-fired facilities, strictly controlling NOx, smoke, SO 2 The emission concentration and total amount of pollutants such as carbon monoxide and other pollutants can be controlled, and the emission of pollutants in flue gas can be reduced, which has significant social and environmental benefits.

[0003] At the same time, in the production process of the aluminum industry, the carbon flue gas produced contains a large amount of fluoride, which seriously endangers human health and plant growth. The "Standard Conditions for the Aluminum Industry" has added the requirement that "when the aluminum carbon anode project uses medium and high sulfur coke raw materials, it must be equipped with an efficient flue gas desulfurization purification device."

[0004] At present, coal-fired power plants and carbon plants need to set up independent flue gas treatment equipment separately. The equipment occupies a large area and the cost of new infrastructure is high. Therefore, while thermal power plants are focusing on reducing the concentration of atmospheric pollutants, it is of great significance to purify the flue gas in the aluminum industry, recover fluorides in the flue gas, and control the emission of pollutants. Summary of the invention

[0005] The purpose of the present invention is to solve at least one of the above-mentioned problems, and this purpose is achieved through the following technical solutions.

[0006] The present invention provides a flue gas co-combustion treatment process, comprising the following steps:

[0007] S1: Lead out the carbon flue gas in the rotary kiln waste heat boiler and transport the carbon flue gas to the flue gas main pipe;

[0008] S2: Carbon flue gas is used as part of the secondary air to enter the combustion system of the power plant boiler to form mixed combustion flue gas;

[0009] S3: The flue gas after co-combustion enters the flue gas treatment system of the power plant unit and is discharged through the main chimney after being treated to meet the standards.

[0010] Furthermore, in step S1, when the carbon flue gas is drawn out from the rotary kiln waste heat boiler, it is pressurized by a booster fan.

[0011] Furthermore, in step S3, before the flue gas after the blending is introduced into the boiler, the air intake volume of the carbon flue gas is adjusted according to the instruction.

[0012] Further, adjusting the air intake of carbon flue gas according to the instruction includes the following steps:

[0013] S31: Detect the current concentration of boiler flue gas in the boiler;

[0014] S32: Compare the detected current boiler flue gas concentration with the preset concentration. If the current boiler flue gas concentration is greater than the preset concentration, increase the carbon flue gas intake volume; if the current boiler flue gas concentration is less than the preset concentration, reduce the carbon flue gas intake volume.

[0015] Furthermore, in step S2, there are multiple flue gas main pipes for collecting carbon flue gas, and each flue gas main pipe is arranged in parallel and is respectively connected to the inner cavity of the boiler.

[0016] The present invention also provides a flue gas treatment device for implementing the flue gas co-firing treatment process as described above, wherein the flue gas treatment equipment includes a rotary kiln waste heat boiler that produces carbon flue gas during the reaction process, a power plant boiler that produces boiler flue gas during the reaction process, and a flue gas main pipe for connecting the rotary kiln waste heat boiler and the power plant boiler.

[0017] Furthermore, a booster fan is provided at the smoke outlet of the rotary kiln waste heat boiler, and the carbon smoke enters the smoke main pipe after being pressurized by the booster fan.

[0018] Furthermore, a smoke damper door is provided in the smoke main pipe.

[0019] Furthermore, the smoke damper door is an adjustable opening structure to adjust the air intake volume of the carbon smoke.

[0020] Furthermore, there are multiple flue gas main pipes, each of which is arranged in parallel and is connected to the inner cavity of the boiler respectively.

[0021] Based on this, compared with the prior art, the flue gas co-combustion treatment process and equipment provided by the present invention have the following beneficial effects:

[0022] Since the primary air of the boiler cannot make the fuel fully burn out and settle, part of the combustible gas is discharged from the flue, resulting in a decrease in the thermal efficiency of the fuel and an increase in fly ash. This requires a part of the secondary air (maximum temperature 300-350℃) to be injected into the furnace space at a higher speed to promote strong stirring and mixing of the flue gas, so that the combustible gas, unburned coal particles and fly ash are fully mixed with the air and burned, reducing the heat loss caused by incomplete combustion, improving thermal efficiency, and reducing air pollution. The boiler secondary air can increase the boiler efficiency by about 5% and save energy by 6%. The invention uses carbon flue gas as the secondary air of the generator set boiler. After the carbon flue gas is introduced into the power plant boiler, it is mixed with the boiler flue gas to form a mixed flue gas. The mixed flue gas is used as the secondary air and injected into the furnace. After the secondary air is completed, the mixed flue gas enters the denitration, dust removal and desulfurization system of the generator set together. After purification, it meets the existing pollutant emission requirements of the power plant and is discharged through the main chimney of the unit. In this way, the process not only provides part of the secondary air for the power plant boiler, but also completes the treatment of the carbon flue gas, thus realizing the coordinated treatment of the flue gas from the carbon plant and the flue gas from the power plant. The flue gas from the carbon plant is treated together with that of the existing boiler, and all the equipment of the original system can be utilized. It has the advantages of low investment and reliable operation, while avoiding some shortcomings of new projects, such as large footprint, heavy workload, and being affected by site conditions, relatively difficult construction, relatively high risks, long transformation period, high investment costs, etc., effectively reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A process flow chart of a specific implementation method of the flue gas co-combustion treatment process provided by the present invention;

[0025] Figure 2 This is a schematic diagram of the flue gas treatment equipment for implementing the flue gas co-combustion treatment process provided by the present invention. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Please refer to Figure 1, Figure 1 The present invention provides a process flow chart of a specific implementation of the flue gas co-combustion treatment process.

[0028] In a specific embodiment, the flue gas co-combustion treatment process provided by the present invention comprises the following steps:

[0029] S1: Lead out the carbon flue gas in the rotary kiln waste heat boiler and transport the carbon flue gas to the flue gas main pipe;

[0030] S2: Carbon flue gas is used as part of the secondary air to enter the combustion system of the power plant boiler to form mixed flue gas; carbon flue gas as part of the secondary air plays a role in supporting combustion, because the combustion temperature in the furnace cannot be reduced;

[0031] S3: The flue gas after co-combustion enters the flue gas treatment system of the power plant unit and is discharged through the main chimney after being treated to meet the standards.

[0032] In step S1, when the carbon flue gas is drawn out from the rotary kiln waste heat boiler, it is pressurized by a booster fan so that the carbon flue gas has a higher pressure before entering the boiler, thereby making the pressure of the secondary air higher and improving the blowing power of the secondary air.

[0033] Under different operating conditions, the concentration of boiler flue gas in the boiler furnace may be different. To ensure the best blending effect, the boiler flue gas and the carbon flue gas should be mixed in an appropriate proportion. In step S3, before the blended flue gas is introduced into the boiler, the air intake of the carbon flue gas is adjusted according to the instructions, so that the air intake of the carbon flue gas can be adjusted according to the concentration of the boiler flue gas in the boiler furnace to ensure a better blending effect.

[0034] Specifically, adjusting the air intake of carbon flue gas according to the instruction includes the following steps:

[0035] S31: Detect the current concentration of boiler flue gas in the boiler;

[0036] S32: Compare the detected current boiler flue gas concentration with the preset concentration. If the current boiler flue gas concentration is greater than the preset concentration, increase the carbon flue gas intake volume; if the current boiler flue gas concentration is less than the preset concentration, reduce the carbon flue gas intake volume.

[0037] Furthermore, in step S2, there are multiple flue gas main pipes for collecting carbon flue gas, and each flue gas main pipe is arranged in parallel and is respectively connected to the inner cavity of the boiler to improve the intake efficiency and amount of carbon flue gas.

[0038] See also Figure 2In addition to the above flue gas co-combustion treatment process, the present invention also provides a flue gas treatment device for implementing the above flue gas co-combustion treatment process, the flue gas treatment device includes a rotary kiln waste heat boiler 1 that generates carbon flue gas during the reaction, a power plant boiler 2 that generates boiler flue gas during the reaction, and a flue gas main pipe 3 for connecting the rotary kiln waste heat boiler and the power plant boiler. The rotary kiln waste heat boilers that generate carbon flue gas are n units, n is greater than or equal to 1, and in this embodiment, there are 2 units; the power plant boilers that generate boiler flue gas are n units, n is greater than or equal to 1, and in this embodiment, there are 3 units; the flue gas treatment equipment also includes desulfurization, denitrification, induced draft and / or dust removal equipment for flue gas treatment.

[0039] A booster fan 4 is provided at the smoke outlet of the rotary kiln waste heat boiler, and the carbon smoke enters the smoke main pipe 3 after being pressurized by the booster fan 4. When the carbon smoke is drawn out from the rotary kiln waste heat boiler 1, it is pressurized by the booster fan 4 so that the carbon smoke has a relatively large pressure before entering the boiler 2, thereby making the pressure of the secondary air relatively large and improving the blowing power of the secondary air.

[0040] A flue gas damper door 5 is provided in the flue gas main pipe 3. Under different working conditions, the concentration of boiler flue gas in the boiler furnace may be different. To ensure the best blending effect, the boiler flue gas and the carbon flue gas should be blended in an appropriate ratio. The flue gas damper door 5 is an opening adjustable structure to adjust the air intake of the carbon flue gas. Before the carbon flue gas in the flue gas main pipe is introduced into the boiler, the opening of the flue gas damper door 5 is adjusted according to the instruction, thereby adjusting the air intake of the carbon flue gas, so that the air intake of the carbon flue gas can be adjusted according to the concentration of the boiler flue gas in the boiler furnace to ensure a better blending effect.

[0041] There are multiple flue gas main pipes, each of which is arranged in parallel and communicated with the inner cavity of the boiler respectively, so as to improve the intake efficiency and intake amount of carbon flue gas.

[0042] Since the primary air of the boiler cannot make the fuel fully burn out and settle, part of the combustible gas is discharged from the flue, resulting in a decrease in the thermal efficiency of the fuel and an increase in fly ash. This requires a part of the secondary air (maximum temperature 300-350℃) to be injected into the furnace space at a higher speed to promote strong stirring and mixing of the flue gas, so that the combustible gas, unburned coal particles and fly ash are fully mixed with the air and burned, reducing the heat loss caused by incomplete combustion, improving thermal efficiency, and reducing air pollution. The boiler secondary air can increase the boiler efficiency by about 5% and save energy by 6%. The invention uses carbon flue gas as part of the secondary air of the generator set boiler. After the carbon flue gas is introduced into the power plant boiler, it is mixed with the boiler flue gas to form a mixed flue gas. The mixed flue gas is used as part of the secondary air and injected into the furnace. After the secondary air is completed, the mixed flue gas enters the denitration, dust removal and desulfurization system of the generator set together. After purification, it meets the existing pollutant emission requirements of the power plant and is discharged through the main chimney of the unit. In this way, the process not only provides secondary air for the power plant boiler, but also completes the treatment of carbon flue gas, thereby realizing the coordinated treatment of carbon plant flue gas and power plant flue gas. The equipment of the original system can be fully utilized, with the advantages of low investment and reliable operation, while avoiding some shortcomings of new projects, such as large footprint, heavy workload, and being affected by site conditions, relatively difficult construction, relatively high risks, long transformation period, high investment costs, etc., effectively reducing production costs.

[0043] Table 1 The influence of carbon flue gas blending on boiler system parameters in a power plant

[0044]

[0045] Table 1 shows the effect of carbon flue gas blending on the parameters of the boiler systems in a power plant. The changes in the parameters are shown in the table above. The heat absorption ratio of each heating surface changes, especially the heat absorption of the convection heating surface increases, but the boiler can still meet the operating requirements through adjustment measures.

[0046] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0047] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. They should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A flue gas co-combustion treatment process, using the following equipment, including a rotary kiln waste heat boiler that generates carbon flue gas during a reaction process, a power plant boiler that generates boiler flue gas during a reaction process, and a flue gas main pipe for connecting the rotary kiln waste heat boiler and the power plant boiler, a booster fan is provided at the smoke outlet of the rotary kiln waste heat boiler, the carbon flue gas enters the flue gas main pipe after being pressurized by the booster fan, a flue gas damper door is provided in the flue gas main pipe, the flue gas damper door is an adjustable opening structure to adjust the air intake of the carbon flue gas, the number of the flue gas main pipes is multiple, each of the flue gas main pipes is arranged in parallel and is respectively connected to the boiler cavity, characterized in that, The following steps are involved: S1: The carbon flue gas in the rotary kiln waste heat boiler is drawn out, and after being pressurized by the booster fan, the carbon flue gas is transported to the flue gas main pipe; S2: Since the primary air of the boiler cannot fully burn and settle the fuel, the carbon flue gas is used as part of the secondary air to enter the power plant boiler combustion system. The carbon flue gas after being pressurized by the booster fan is sprayed into the furnace space to form the flue gas after mixing and burning. The temperature of the secondary air is 300-350℃; S3: The flue gas after blending enters the flue gas treatment system of the power plant unit and is discharged through the main chimney after being treated to meet the standards; Before the mixed flue gas is introduced into the boiler, the air intake of the carbon flue gas is adjusted according to the instructions.

2. The flue gas co-combustion treatment process according to claim 1, characterized in that: Adjusting the air intake of carbon flue gas according to the instruction includes the following steps: S31: Detect the current concentration of boiler flue gas in the boiler; S32: Compare the detected current boiler flue gas concentration with the preset concentration. If the current boiler flue gas concentration is greater than the preset concentration, increase the carbon flue gas intake volume; if the current boiler flue gas concentration is less than the preset concentration, reduce the carbon flue gas intake volume.

3. The flue gas co-combustion treatment process according to claim 1, characterized in that: In step S2, there are multiple flue gas main pipes for collecting carbon flue gas, and each flue gas main pipe is arranged in parallel and is respectively connected to the inner cavity of the boiler.

Images