CN113324405B - Steel rolling heating furnace and method for flue gas denitration - Google Patents
Steel rolling heating furnace and method for flue gas denitration Download PDFInfo
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- CN113324405B CN113324405B CN202110514989.8A CN202110514989A CN113324405B CN 113324405 B CN113324405 B CN 113324405B CN 202110514989 A CN202110514989 A CN 202110514989A CN 113324405 B CN113324405 B CN 113324405B
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- 238000010438 heat treatment Methods 0.000 title claims abstract description 76
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 65
- 239000003546 flue gas Substances 0.000 title claims abstract description 65
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 34
- 239000010959 steel Substances 0.000 title claims abstract description 34
- 238000005096 rolling process Methods 0.000 title claims abstract description 33
- 238000000034 method Methods 0.000 title claims abstract description 25
- 239000007921 spray Substances 0.000 claims abstract description 104
- 238000006243 chemical reaction Methods 0.000 claims abstract description 47
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 31
- 238000002347 injection Methods 0.000 claims abstract description 12
- 239000007924 injection Substances 0.000 claims abstract description 12
- 238000011084 recovery Methods 0.000 claims abstract description 11
- 238000002791 soaking Methods 0.000 claims abstract description 6
- 238000005507 spraying Methods 0.000 claims description 21
- 239000011229 interlayer Substances 0.000 claims description 6
- 238000001816 cooling Methods 0.000 claims description 4
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 abstract description 49
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 18
- 235000011114 ammonium hydroxide Nutrition 0.000 description 18
- 230000000694 effects Effects 0.000 description 16
- 230000008569 process Effects 0.000 description 13
- 230000002411 adverse Effects 0.000 description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 238000012986 modification Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- 239000010410 layer Substances 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000003344 environmental pollutant Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 231100000719 pollutant Toxicity 0.000 description 2
- 239000011819 refractory material Substances 0.000 description 2
- 239000000779 smoke Substances 0.000 description 2
- 239000010963 304 stainless steel Substances 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229910000589 SAE 304 stainless steel Inorganic materials 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 230000003044 adaptive effect Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
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- 238000002485 combustion reaction Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
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- 238000010586 diagram Methods 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 239000002737 fuel gas Substances 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 210000003127 knee Anatomy 0.000 description 1
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- 239000000463 material Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000013618 particulate matter Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
- F27B9/12—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity with special arrangements for preheating or cooling the charge
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/54—Nitrogen compounds
- B01D53/56—Nitrogen oxides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/77—Liquid phase processes
- B01D53/79—Injecting reactants
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
- F27B9/30—Details, accessories, or equipment peculiar to furnaces of these types
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/004—Systems for reclaiming waste heat
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/008—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases cleaning gases
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/206—Ammonium compounds
- B01D2251/2062—Ammonia
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
- F27B9/12—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity with special arrangements for preheating or cooling the charge
- F27B2009/122—Preheating
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- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Tunnel Furnaces (AREA)
Abstract
The invention particularly relates to a steel rolling heating furnace and a method for flue gas denitration, belonging to the technical field of flue gas denitration, wherein the heating furnace comprises: the heating furnace body comprises a heat recovery section, a preheating section, a first heating section, a second heating section and a soaking section in sequence along the flow direction of flue gas; one end of the heat recovery section, which is close to the preheating section, is provided with a denitration reaction zone; the reducing agent injection system comprises a blank lower spray gun group and a pair of furnace top spray gun groups; the lower blank spray gun group comprises at least one pair of long guns and at least one pair of short guns, and the long guns and the short guns are respectively arranged on the two furnace side walls of the denitration reaction zone; the furnace top spray gun group comprises a plurality of furnace top spray guns, the furnace top spray guns are linearly distributed and are arranged on the furnace top of the denitration reaction area, and the pair of furnace top spray gun groups are symmetrically distributed in a V shape; the average emission of nitrogen oxides by adopting the heating furnace provided by the invention is 300mg/m 3 Reduced to 80mg/m 3 And the denitration rate reaches more than 70%.
Description
Technical Field
The invention belongs to the technical field of flue gas denitration, and particularly relates to a steel rolling heating furnace and a steel rolling heating method for flue gas denitration.
Background
Nitrogen Oxides (NO) x ) The main pollutants which are caused by the atmospheric pollution comprise NO and N 2 O、NO 3 、N 2 O 3 、N 2 O 4 And N 2 O 5 Etc. the evolution of nitrogen oxides in the atmosphere leads to the formation of nitric acid and nitrate-containing particulate matter, one of the major pollutants responsible for the formation of acid rain. Nitrogen and oxygen in heating furnace flue gasThe compound is a heavy-point pollution source of a hot rolling mill, and the emission limit value of nitrogen oxides is 300mg/Nm along with the implementation of the ultralow emission standard of flue gas 3 Reduced to 150mg/Nm 3 NO of the burners of the heating furnaces for rolling steel in most of the steel mills at present x The initial design value is generally 200mg/Nm 3 ～400mg/Nm 3 And the requirement of ultralow emission standard cannot be met, and enterprises face the risk of limited production. At present, three main technical approaches for reducing nitrogen emission of a heating furnace are provided, one is: the low-nitrogen oxide combustor is utilized to reduce the generation of nitrogen oxides by improving the mixed combustion condition of air and fuel gas; secondly, eliminating nitrogen oxides by chemical reaction by using a denitration facility; and thirdly, an oxygen enrichment technology is adopted to reduce the proportion of nitrogen in the combustion-supporting gas. In the implementation process of the technologies, the most economical and remarkable effect is to add a denitration device.
The main stream flue gas denitration process mainly comprises SNCR and SCR, wherein the SCR process is gradually applied to part of heating furnaces, but the process needs additional forced smoke exhaust devices, catalysts and other auxiliary equipment, so that the investment is huge, and the catalyst consumption and the equipment power consumption need to be continuously maintained. The SNCR process has less investment and simple equipment structure, but the applicant finds that: the SNCR process is rarely applied to a steel rolling heating furnace, the main reasons are that the temperature change in the steel rolling heating furnace is frequent, a hearth is wide, the stable reaction temperature and the full mixing of the flue gas and the denitrifying agent cannot be ensured, and the denitrifying rate is generally below 50%.
The invention relates to a flue gas denitration system and a flue gas denitration process of a steel rolling heating furnace, which are disclosed by the Chinese patent application 2019103070189.9.
Disclosure of Invention
In view of the above problems, the present invention has been made to provide a steel rolling heating furnace and a method for flue gas denitration that overcome or at least partially solve the above problems.
The embodiment of the invention provides a steel rolling heating furnace for flue gas denitration, which comprises:
the heating furnace body comprises a heat recovery section, a preheating section, a first heating section, a second heating section and a soaking section in sequence along the flowing direction of flue gas; a denitration reaction zone is arranged at one end of the heat recovery section, which is close to the preheating section;
the reducing agent injection system is used for injecting a reducing agent to the denitration reaction zone and comprises a blank lower spray gun group and a pair of furnace top spray gun groups; the lower blank spray gun group is used for spraying a reducing agent to the lower part of a plate blank in the denitration reaction zone, the lower blank spray gun group comprises at least one pair of long guns and at least one pair of short guns, the long guns are respectively arranged on two furnace side walls of the denitration reaction zone, the distance a between a nozzle of the long gun and the furnace side walls is =1/8 c-3/8 c, wherein c is the width of the furnace body of the heating furnace, the short guns are respectively arranged on the two furnace side walls of the denitration reaction zone, and the distance b between the nozzle of the short gun and the furnace side walls is =30 mm-80 mm; the furnace top spray gun group is used for spraying a reducing agent to the upper part of a plate blank in the denitration reaction zone, the furnace top spray gun group comprises a plurality of furnace top spray guns, the furnace top spray guns are linearly distributed and installed on a furnace top of the denitration reaction zone, a pair of the furnace top spray gun groups are symmetrically distributed in a V shape, and the axes of the pair of the furnace top spray gun groups and the central axis of the furnace body of the heating furnace are located on the same vertical plane.
Optionally, the distance d =0.1 m-0.3 m between two adjacent top lances of the top lance group is measured in the flow direction of the flue gas.
Optionally, the distance d =1m to 1.4m between two adjacent top lances of the top lance group is measured in a direction perpendicular to the flow direction of the flue gas.
Optionally, the spraying angle of the furnace top spray gun is 30-45 degrees, and the spraying length of the furnace top spray gun is 0.5-1 m.
Optionally, the top lance group comprises 2-5 top lances.
Optionally, the spraying length of the long gun and the short gun is 2.5 m-3 m.
Optionally, the flow direction of the flue gas is measured, a first temperature sensor is arranged on the plane of the head of the furnace top spray gun group, and a second temperature sensor is arranged on the plane of the tail of the furnace top spray gun group.
Optionally, the long gun jacket is provided with a cold air sleeve, an interlayer is arranged between the cold air sleeve and the long gun, and the interlayer is connected with a cooling system.
Optionally, the long lance is erected in the denitration reaction zone through a support wall.
Based on the same inventive concept, the embodiment of the invention also provides a flue gas denitration method, which is characterized by comprising the following steps: the steel rolling heating furnace for flue gas denitration is adopted for SNCR denitration, and the temperature of the preheating section is adjusted to enable the temperature of the denitration reaction zone to be 850-1050 ℃.
One or more technical solutions in the embodiments of the present invention at least have the following technical effects or advantages:
the embodiment of the invention provides a steel rolling heating furnace for flue gas denitration, which comprises: the heating furnace body comprises a heat recovery section, a preheating section, a first heating section, a second heating section and a soaking section in sequence along the flowing direction of flue gas; a denitration reaction zone is arranged at one end of the heat recovery section, which is close to the preheating section; the reducing agent injection system is used for injecting a reducing agent to the denitration reaction zone and comprises a blank lower spray gun group and a pair of furnace top spray gun groups; the lower blank spray gun group is used for spraying a reducing agent to the lower part of a plate blank in the denitration reaction zone, the lower blank spray gun group comprises at least one pair of long guns and at least one pair of short guns, the long guns are respectively arranged on two furnace side walls of the denitration reaction zone, the distance a between a nozzle of the long gun and the furnace side walls is =1/8 c-3/8 c, wherein c is the width of the furnace body of the heating furnace, the short guns are respectively arranged on the two furnace side walls of the denitration reaction zone, and the distance b between the nozzle of the short gun and the furnace side walls is =30 mm-80 mm; the furnace top spray gun group is used for spraying reducing agent to the upper part of the plate blank in the denitration reaction zone, the furnace top spray gun group comprises a plurality of furnace top spray guns, the furnace top spray guns are linearly distributed and arranged on the furnace top of the denitration reaction zone, and a pair of furnaces are arrangedThe top spray gun groups are symmetrically distributed in a V shape, and the axes of the pair of furnace top spray gun groups and the central axis of the furnace body of the heating furnace are positioned on the same vertical plane; the average emission of nitrogen oxides in the heating furnace provided by the invention is 300mg/m 3 Reduced to 80mg/m 3 And the denitration rate reaches more than 70%.
The above description is only an overview of the technical solutions of the present invention, and the present invention can be implemented in accordance with the content of the description so as to make the technical means of the present invention more clearly understood, and the above and other objects, features, and advantages of the present invention will be more clearly understood.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 is a schematic view of a furnace body structure of a heating furnace provided in an embodiment of the present invention;
FIG. 2 is a first schematic view of a spray gun arrangement provided by an embodiment of the present invention;
FIG. 3 is a schematic diagram of a second arrangement of spray guns according to an embodiment of the present invention;
reference numerals are as follows: 1-heating furnace body, 11-heat recovery section, 12-preheating section, 13-first heating section, 14-second heating section, 15-soaking section, 21-blank lower spray gun group, 211-long gun, 211 a-cold air sleeve, 212-short gun, 22-furnace top spray gun group, 31-first temperature sensor and 32-second temperature sensor.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are illustrative of the invention and are not to be construed as limiting the invention.
Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.
Unless otherwise specifically indicated, various raw materials, reagents, instruments, equipment and the like used in the present invention may be commercially available or may be prepared by existing methods.
In order to solve the technical problems, the general idea of the embodiment of the application is as follows:
the applicant finds in the course of the invention: the SNCR denitration process has higher difficulty in the heating furnace, on one hand, because the width of a hearth of the steel rolling heating furnace reaches 11m and the hearth is divided into an upper layer and a lower layer by a plate blank, the reducing agent and the flue gas are mixed fully and difficultly; on the other hand, the temperature range of the reaction of the reducing agent and the nitrogen oxide in the SNCR process is 850-1050 ℃, and the window is narrow. This causes a lower denitration efficiency and makes it difficult to achieve the desired effect.
According to an exemplary embodiment of the present invention, there is provided a flue gas denitration steel rolling heating furnace, including:
the heating furnace body comprises a heat recovery section, a preheating section, a first heating section, a second heating section and a soaking section in sequence along the flow direction of flue gas; a denitration reaction zone is arranged at one end of the heat recovery section, which is close to the preheating section;
the reducing agent injection system is used for injecting a reducing agent to the denitration reaction zone and comprises a blank lower spray gun group and a pair of furnace top spray gun groups; the lower blank spray gun group is used for spraying a reducing agent to the lower part of a plate blank in the denitration reaction zone, the lower blank spray gun group comprises at least one pair of long guns and at least one pair of short guns, the long guns are respectively arranged on two furnace side walls of the denitration reaction zone, the distance a between a nozzle of the long gun and the furnace side walls is =1/8 c-3/8 c, wherein c is the width of the furnace body of the heating furnace, the short guns are respectively arranged on the two furnace side walls of the denitration reaction zone, and the distance b between the nozzle of the short gun and the furnace side walls is =30 mm-80 mm; the furnace top spray gun group is used for spraying a reducing agent to the upper part of a plate blank in the denitration reaction zone, the furnace top spray gun group comprises a plurality of furnace top spray guns, the furnace top spray guns are linearly distributed and installed on a furnace top of the denitration reaction zone, a pair of the furnace top spray gun groups are symmetrically distributed in a V shape, and the axes of the pair of the furnace top spray gun groups and the central axis of the furnace body of the heating furnace are located on the same vertical plane.
By adopting the design, the reducing agent injection system comprises the blank lower spray gun group and the pair of furnace top spray gun groups, the problem that the hearth is divided into an upper part and a lower part by the blank plate and the full mixing of the flue gas and the reducing agent is difficult to realize can be solved, and meanwhile, the pair of furnace top spray gun groups distributed in a V shape can adapt to the distribution of the flue gas flow field in the furnace, namely the flow velocity of the flue gas in the middle of the hearth is high, and is gradually reduced towards two sides, so that the full mixing of the reducing agent and the flue gas is better realized; the blank lower spray gun group comprises at least one pair of long guns and at least one pair of short guns, the problem that the width of a hearth for heating a plate blank is wide can be solved, the width of the hearth of a steel rolling heating furnace is mostly 10m to 12m at present, the blank lower spray gun group provided by the embodiment comprises at least one pair of long guns and at least one pair of short guns, and when the width of the hearth of the steel rolling heating furnace adopted is not in the range provided by the embodiment, a person skilled in the art can make adaptive adjustment according to the width of the hearth of the steel rolling heating furnace, for example, when the width of the hearth of the steel rolling heating furnace is more than 12m, the gun group can be properly added, and in short, the spray points with reducing agents uniformly distributed on the lower part of the plate blank are realized.
As an alternative embodiment, the distance d =0.1m to 0.3m between two adjacent top lances of the top lance group, measured in the flow direction of the flue gas.
The flue gas has different flow velocities at the same section, so the temperature of the flue gas is different, the temperature of the flue gas close to the central line area of the hearth is higher, the temperature of two sides of the flue gas is lower, the difference of 0.1-0.3 m can meet the condition that a spray gun at the central part of the furnace top and spray guns at two sides are simultaneously in an additional reaction temperature interval, and the adverse effect of overlarge and undersize values of the distance is that the optimal temperature interval of the denitration reaction is separated.
As an alternative embodiment, the distance d =1 m-1.4 m between two adjacent top lances of the top lance group, measured perpendicular to the flow direction of the flue gas.
Generally speaking, the width of a hearth of a steel rolling heating furnace is 10m to 12m, when the furnace is actually used, a pair of roof spray gun groups commonly comprises 8 roof spray guns, namely, one roof spray gun group comprises 4 roof spray guns, the 8 roof spray guns are uniformly distributed along the width direction of the hearth of the steel rolling heating furnace, when the width of the adopted hearth of the steel rolling heating furnace is not in the range provided by the embodiment, the number of the roof spray guns can be properly increased or decreased according to the actual situation, specifically, one roof spray gun group comprises 2 to 5 roof spray guns, the roof spray gun group can adapt to most of the hearths of the steel rolling heating furnace, the distance d =1m to 1.4m between two adjacent roof spray guns is measured in the width direction of the hearth of the steel rolling heating furnace, and the adverse effect of excessively large value of the distance is that ammonia water sprayed by each two spray guns cannot be effectively superposed, and part of smoke gas cannot react with the ammonia water; the undersize adverse effect is that the ammonia water that two spray guns spun coincides, causes same cross section ammonia water concentration fluctuation big, and the equipartition ammonia water is excessive or not enough, influences the denitration rate.
In an alternative embodiment, the ejection angle of the top lance is 30 ° to 45 °, and the ejection length of the top lance is 0.5m to 1m, where the angle is an angle between the outer edge of the sector formed after the ammonia water is ejected and the vertical direction.
The reason for controlling the spraying angle of the top spray gun to be 30-45 degrees is that the ammonia water sprayed by the two spray guns slightly coincides and fully reacts with the flue gas, and the adverse effect of over-small angle value is that the ammonia water cannot effectively coincide, and part of the flue gas cannot react with the ammonia water, so that the denitration rate is influenced. The overlarge adverse effect is that the concentration fluctuation of ammonia water with the same section is large, the ammonia water is distributed excessively or insufficiently, and the denitration rate is influenced.
The reason for controlling the spraying length of the furnace top spray gun to be 0.5 m-1 m is to ensure that ammonia water and flue gas are fully mixed and reacted, the adverse effect of over-small length is that the ammonia water and the flue gas are not fully mixed, a reaction temperature range is separated, and the over-large adverse effect is that the ammonia water and the flue gas are directly sprayed to the surface of a plate blank, the quality of the plate blank is influenced, and the mixing degree with the flue gas is reduced.
As an alternative embodiment, the long lance and the short lance have a spray length of 2.5m to 3m.
The reason for controlling the spraying length of 2.5 m-3 m of the long gun and the short gun is that the ammonia water and the flue gas are fully mixed in the width direction of the furnace through the matching of the inserting depth and the spraying length of four spray guns (the spraying limit length of a common spray gun is 2.5-3 m); the adverse effect that the length value is too large is that the equipment cost is high, the cost investment is large, and the adverse effect that the ammonia water is too small can not be ensured to be fully mixed with the flue gas in the furnace width direction.
In an alternative embodiment, a first temperature sensor is arranged on the plane of the head part of the furnace top spray gun group, and a second temperature sensor is arranged on the plane of the tail part of the furnace top spray gun group according to the flow direction of the flue gas.
By adopting the design, the temperature range of the denitration reaction zone can be known in real time, so that the heating temperature of the preset section can be adjusted in time, and the temperature of the denitration reaction zone can be kept in the temperature range of the reaction of the reducing agent and the nitrogen oxide.
As an optional implementation mode, the long gun is sleeved with a cold air sleeve, an interlayer is arranged between the cold air sleeve and the long gun, and the interlayer is connected with a cooling system.
As the campaign period of each heating furnace is about 8-12 months, the stable operation of the spray gun needs to be ensured in the period. The long rifle of lower part is arranged in the stove, if appear warping the scheduling problem, can't in time handle, seriously influences denitration efficiency, consequently need arrange cold wind sleeve pipe in the spray gun outside, lets in the air cooling spray gun for a long time, and the rifle body of the part adopts 310S and above grade stainless steel material deeply into the stove simultaneously to 2/3 department uses refractory material to build by laying bricks or stones the knee wall deep into the stove, prevents that spray gun stress deformation from influencing injection effect. The rest spray guns are made of 304 and above grade stainless steel.
According to another exemplary embodiment of the present invention, there is provided a method for denitration of flue gas, which is characterized by comprising: the steel rolling heating furnace for flue gas denitration is adopted for SNCR denitration, and the temperature of the preheating section is adjusted to enable the temperature of the denitration reaction zone to be 850-1050 ℃.
The steel rolling heating furnace and the method for flue gas denitration according to the present application will be described in detail with reference to examples, comparative examples and experimental data.
Example 1
The heating furnace adopts an SNCR denitration process and mainly comprises a reducing agent storage system, a reducing agent conveying and online diluting system, a pipeline, a valve, a metering and distributing system, an injection system, an electrical system and an automatic control system. Except the injection system, all the other parts are controlled according to the conventional process. The spraying system was implemented as follows.
The effective width of a hearth of the heating furnace is 11.7m, 8 spray guns are arranged on the top of the furnace at the interval of 1.3m, the spray guns are evenly distributed on the top of the furnace in a V shape in consideration of the distribution of flue gas flow fields in the furnace, and are divided into four layers with the interval of 0.2m in each layer. The injection angle of the reducing agent ammonia water is 30-45 degrees, the injection length is 0.5-1 m, thermocouples are respectively arranged on the corresponding planes of the No. 1 nozzle and the No. 4 nozzle and are used for detecting the temperature in the furnace, and the temperature of the two thermocouples is controlled to be 900-1000 ℃ by adjusting the temperature of the preheating section, so that the reducing agent ammonia water and the nitrogen oxide in the flue gas have reaction conditions.
The lower spray guns are arranged at the side wall part of the furnace body, two pairs of spray guns are arranged, and the short spray guns penetrate into the hearth by 30-80 mm; the insertion depth of the long gun is one fourth of the width of the hearth, the injection length of the reducing agent ammonia is 2.5-3m, and the reducing agent and the flue gas are fully mixed. A cold air sleeve is arranged outside the long spray gun, the air is introduced for a long time to cool the spray gun, meanwhile, the gun body of the part deep into the furnace is made of 310S stainless steel, and a refractory material is used for building a support wall at a 2/3 position deep into the furnace, so that the stress deformation of the spray gun is prevented from influencing the spraying effect. The rest spray guns are made of 304 stainless steel.
After the system is put into operation, the concentration of nitrogen oxides is 245mg/Nm 3 Down to 65mg/Nm 3 And the denitration rate reaches 73 percent.
One or more technical solutions in the embodiments of the present invention at least have the following technical effects or advantages:
(1) The furnace top spray guns of the heating furnace provided by the embodiment of the invention are uniformly distributed in a V shape, the distribution of a flue gas flow field in the furnace is fully considered, the flow velocity of the flue gas in the middle of a hearth is high, and the flue gas flow velocity is gradually reduced towards two sides;
(2) The heating furnace provided by the embodiment of the invention is provided with the thermocouples, and the thermocouples are used for detecting the temperature in the furnace, controlling the temperature of the two thermocouples to be 850-1050 ℃ by adjusting the temperature of the preheating section, and enabling the reducing agent and the nitrogen oxide in the flue gas to have reaction conditions;
(3) The heating furnace provided by the embodiment of the invention can enable the average emission of nitrogen oxides to be 300mg/m 3 Reduced to 80mg/m 3 And the denitration rate reaches more than 70%.
Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (7)
1. The utility model provides a flue gas denitration's steel rolling heating furnace which characterized in that, the heating furnace includes:
the heating furnace body comprises a heat recovery section, a preheating section, a first heating section, a second heating section and a soaking section in sequence along the flowing direction of flue gas; a denitration reaction zone is arranged at one end of the heat recovery section, which is close to the preheating section; the reducing agent injection system is used for injecting a reducing agent to the denitration reaction zone and comprises a blank lower spray gun group and a pair of furnace top spray gun groups; the lower blank spray gun group is used for spraying a reducing agent to the lower part of a plate blank in the denitration reaction zone, the lower blank spray gun group comprises at least one pair of long guns and at least one pair of short guns, the long guns are respectively arranged on two furnace side walls of the denitration reaction zone, the distance a between a nozzle of the long gun and the furnace side walls is =1/8 c-3/8 c, wherein c is the width of the furnace body of the heating furnace, the short guns are respectively arranged on the two furnace side walls of the denitration reaction zone, and the distance b between the nozzle of the short gun and the furnace side walls is =30 mm-80 mm; the furnace top spray gun group is used for spraying a reducing agent to the upper part of a plate blank in the denitration reaction zone, the furnace top spray gun group comprises a plurality of furnace top spray guns, the furnace top spray guns are linearly distributed and are arranged on the furnace top of the denitration reaction zone, a pair of the furnace top spray gun groups are mutually symmetrical and are distributed in a V shape, and the axes of the pair of the furnace top spray gun groups and the central axis of the furnace body of the heating furnace are positioned on the same vertical plane;
the distance d between two adjacent furnace top spray guns of the furnace top spray gun group is =0.1 m-0.3 m by the flowing direction of the flue gas;
the spraying angle of the furnace top spray gun is 30-45 degrees, and the spraying length of the furnace top spray gun is 0.5-1 m;
and a first temperature sensor is arranged on the plane of the head part of the furnace top spray gun group, and a second temperature sensor is arranged on the plane of the tail part of the furnace top spray gun group.
2. The steel rolling heating furnace with flue gas denitration of claim 1, wherein the distance d =1 m-1.4 m between two adjacent top lances of the top lance group in the direction perpendicular to the flow direction of the flue gas.
3. The steel rolling heating furnace with flue gas denitration of claim 1, wherein the roof lance group comprises 2-5 roof lances.
4. The flue gas denitrated steel rolling heating furnace according to claim 1, wherein the spraying lengths of the long lance and the short lance are 2.5m to 3m.
5. The steel rolling heating furnace with flue gas denitration of claim 1, wherein the long gun is sleeved with a cold air sleeve, an interlayer is arranged between the cold air sleeve and the long gun, and the interlayer is connected with a cooling system.
6. The flue gas denitrated steel rolling heating furnace according to claim 1, wherein the lance is erected in the denitration reaction zone through a support wall.
7. A method for denitration of flue gas, which is characterized by comprising the following steps: the SNCR denitration is carried out by adopting the steel rolling heating furnace for flue gas denitration of any one of claims 1 to 6, and the temperature of the preheating section is adjusted to ensure that the temperature of the denitration reaction zone is 850-1050 ℃.
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| CN203281218U (en) * | 2013-06-04 | 2013-11-13 | 广西博世科环保科技股份有限公司 | SNCR denitration temperature control device of cement kiln |
| CN203990305U (en) * | 2014-06-10 | 2014-12-10 | 湖南正明环境工程有限公司 | A kind of multidirectional injection SNCR adds individual layer SCR denitrating system |
| US20180347813A1 (en) * | 2017-06-06 | 2018-12-06 | Ola Ritzén | Method and device for heating a furnace |
| CN110013752A (en) * | 2019-04-17 | 2019-07-16 | 中晟工程技术(天津)有限公司 | A kind of heater for rolling steel flue gas denitrification system and technique |
| CN209960514U (en) * | 2019-05-23 | 2020-01-17 | 米凯利科技（北京）有限公司 | Waste liquid incineration spray gun and waste liquid pumping incineration system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN203281218U (en) * | 2013-06-04 | 2013-11-13 | 广西博世科环保科技股份有限公司 | SNCR denitration temperature control device of cement kiln |
| CN203990305U (en) * | 2014-06-10 | 2014-12-10 | 湖南正明环境工程有限公司 | A kind of multidirectional injection SNCR adds individual layer SCR denitrating system |
| US20180347813A1 (en) * | 2017-06-06 | 2018-12-06 | Ola Ritzén | Method and device for heating a furnace |
| CN110013752A (en) * | 2019-04-17 | 2019-07-16 | 中晟工程技术(天津)有限公司 | A kind of heater for rolling steel flue gas denitrification system and technique |
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