CN112316587A - Sintering flue gas circulation combined full-pollutant integrated treatment device - Google Patents

Sintering flue gas circulation combined full-pollutant integrated treatment device Download PDF

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CN112316587A
CN112316587A CN202011380986.1A CN202011380986A CN112316587A CN 112316587 A CN112316587 A CN 112316587A CN 202011380986 A CN202011380986 A CN 202011380986A CN 112316587 A CN112316587 A CN 112316587A
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flue gas
denitration
desulfurization
dust removal
sintering
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呼广辉
刘国锋
刘晓敏
李转丽
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Beijing ZHTD Environmental Protection Technology Co Ltd
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Beijing ZHTD Environmental Protection Technology Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/02—Particle separators, e.g. dust precipitators, having hollow filters made of flexible material
    • 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
    • B01D53/346—Controlling the process
    • 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
    • B01D53/48—Sulfur compounds
    • B01D53/50—Sulfur 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
    • B01D53/86—Catalytic processes
    • B01D53/8621—Removing nitrogen compounds
    • B01D53/8625—Nitrogen oxides
    • B01D53/8631—Processes characterised by a specific device
    • 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
    • B01D53/86—Catalytic processes
    • B01D53/90—Injecting reactants

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  • Chemical & Material Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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  • Biomedical Technology (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Treating Waste Gases (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)

Abstract

The invention provides a sintering flue gas circulation and total pollutant combined integrated treatment device, which is used for treating sintering flue gas discharged by a sintering machine and comprises a sintering flue gas circulation system and an externally discharged flue gas purification system; the sintering flue gas circulating system comprises a gas-gas heat exchanger, a built-in combustion furnace and a dust removal and denitration integrated device; the second path of flue gas is subjected to temperature rise treatment by the gas-gas heat exchanger, then passes through the built-in combustion furnace, enters the dust removal and denitration integrated device after the first denitration is completed at the built-in combustion furnace, is subjected to second denitration and third denitration, is discharged by the dust removal and denitration integrated device, and then enters the sintering machine along the circulating flue to participate in the sintering process again; the external exhaust flue gas purification system comprises a desulfurization and dust removal integrated device, wherein the first path of flue gas and the third path of flue gas subjected to heat exchange and temperature reduction by the gas-gas heat exchanger are converged into one path of mixed flue gas, and the mixed flue gas enters the desulfurization and dust removal integrated device for desulfurization and dust removal treatment and then is discharged by an external exhaust flue.

Description

Sintering flue gas circulation combined full-pollutant integrated treatment device
Technical Field
The invention relates to the field of ultralow-emission flue gas treatment in the steel industry, in particular to a sintering flue gas circulation combined full-pollutant integrated treatment device.
Background
The iron and steel industry belongs to the high pollution industry, a large amount of flue gas is generated in the iron ore sintering process, and in addition, because the air leakage rate of a domestic sintering machine is high (more than 40 percent), a considerable part of air directly enters a subsequent flue gas treatment device without passing through a sinter bed, the sintering flue gas amount is huge. Such as a 360m stand2When the sintering machine is normally produced, the discharged smoke quantity is up to 216 ten thousand cubic meters (m) per hour3H) above. Besides large amount of sintering flue gas, the method also has the advantages of concentrated emission source, large flue gas temperature fluctuation (changed along with the condition of the sintering process), much carried dust, higher CO content and SO2The concentration is lower, the moisture content is large, corrosive gas and dioxin substances are contained, and the like, so that the influence on the local atmospheric quality is large, and serious environmental pollution can be caused, and therefore, the sintering flue gas pollutants need to be purified, and the effects of environmental protection and emission reduction are achieved.
At present, the atmospheric pollutant treatment measures of steel enterprises in China can be roughly summarized into three categories: 1. basic conditions of raw material control and flue gas emission reduction; 2. an effective means of controlling the sintering process and reducing the emission of flue gas; 3. the final means and the final guarantee of the flue gas treatment. Among the three treatment measures, people often pay more attention to the tail end treatment of the flue gas. At present, the tail end treatment of sintering flue gas mainly comprises active coke desulfurization and denitration integration, flue gas desulfurization (wet method, dry method and semi-dry method), dust removal and SCR denitration integration and other technologies.
The integrated technology of desulfurization and denitrification of the active coke mainly has the defects of huge investment, difficult bearing of common enterprises, large loss of the active coke, high operation cost, complex process, increased energy consumption due to large pressure drop of flue gas passing through an adsorption bed, pipeline blockage caused by ammonia injection, slow desulfurization rate and the like. In the engineering, the integration of flue gas desulfurization, dust removal and denitration often directly adopts the series mode of "desulfurization + dust removal + denitration", does not realize real desulfurization, dust removal and denitration integration technique, does not really reduce project investment, running cost yet to area is big, and the construction period is long, causes very big pressure for the enterprise.
With the continuous departure of national and local standards such as the modification of the "emission standards of atmospheric pollutants for the steel sintering and pelletizing industry" (GB 28662 and 2012), the emission limit of flue gas pollutants in the steel industry is becoming lower and lower, and the emission limit can only be reached by increasing the scale of the device and increasing the amounts of desulfurizing agent, ammonia, catalyst, etc., by the end desulfurization/denitrification treatment technology, which inevitably leads to great pressure in enterprises.
Under the background, the method is not only limited to the tail end treatment of the flue gas, but also is particularly urgent when the method is focused on the whole flow treatment of the sintering flue gas.
Disclosure of Invention
The invention aims to provide a sintering flue gas circulation and full pollutant combined integrated treatment device, which realizes the organic combination of a sintering flue gas circulation technology and a desulfurization, dedusting and denitration integrated technology, saves investment and operation cost, reduces the occupied area and shortens the construction period.
In order to achieve the above purpose, the invention provides the following technical scheme:
a sintering flue gas circulation and full pollutant combined integrated treatment device is used for treating sintering flue gas discharged by a sintering machine and comprises a sintering flue gas circulation system and an externally discharged flue gas purification system; the head of the sintering machine is communicated with a machine head flue, a first path of flue gas flows in the machine head flue, the middle front section of the sintering machine is communicated with a middle front section flue, a second path of flue gas flows in the middle front section flue, the middle rear section of the sintering machine is communicated with a middle rear section flue, and a third path of flue gas flows in the middle rear section flue; the sintering flue gas circulating system comprises a gas-gas heat exchanger, a built-in combustion furnace and a dust removal and denitration integrated device; the second path of flue gas is subjected to temperature rise treatment by the gas-gas heat exchanger, then passes through the built-in combustion furnace, and completes the first denitration at the built-in combustion furnace, the second path of flue gas after the first denitration enters the dust removal and denitration integrated device to complete the second denitration and the third denitration, and the second path of flue gas is discharged by the dust removal and denitration integrated device and then enters the sintering machine along the circulating flue to participate in the sintering process again; the outer exhaust flue gas purification system comprises a desulfurization and dust removal integrated device, the first path of flue gas and the third path of flue gas subjected to heat exchange and temperature reduction through the gas-gas heat exchanger are converged into a path of mixed flue gas and enter the desulfurization and dust removal integrated device through a mixed flue to be subjected to desulfurization and dust removal treatment, and the mixed flue gas subjected to desulfurization and dust removal treatment is discharged from an outer exhaust flue.
Further, the dust removal and denitration integrated device comprises a plurality of dust removal and denitration units, a back flushing device, a second ammonia spraying grid, a second denitration unit, a box body, an ash bucket and an assembling plate; the assembly plate is arranged in the box body and divides the box body into a lower box body and an upper box body; the multiple dust removal and denitration units are arranged in the lower box body, a honeycomb-shaped activated carbon tube is arranged in each dust removal and denitration unit, an SCR denitration catalyst is loaded in each honeycomb-shaped activated carbon tube, and the honeycomb-shaped activated carbon tube is a first denitration unit; the back blowing device, the second ammonia spraying grid and the second denitration unit are all arranged in the upper box body, the back blowing device is arranged above the assembling plate, and a blowing port of the back blowing device is over against the dedusting and denitration unit; the ash bucket is connected with the lower end of the lower box body, the lower end of the lower box body is open, and the ash bucket is communicated with the lower box body; the second denitration unit is arranged above the back flushing device, and an SCR denitration catalyst layer is arranged in the second denitration unit; the second ammonia injection grid is arranged between the second denitration unit and the back blowing device, and a nozzle of the second ammonia injection grid faces the dust removal denitration unit; and the second flue gas enters the lower box body, the dedusting treatment and the second denitration treatment are completed at the first denitration unit, the second flue gas enters the upper box body after being treated by the first denitration unit, the third denitration is completed in the second denitration unit, and the second flue gas after being denitrated for the third time is discharged from the upper box body.
Further, the dust removal and denitration unit comprises a dust removal filter bag, a bag cage and a clean flue gas channel; the dust removal filter bag is of a cylinder structure and consists of one to four filter bags, the bag cage is supported on the inner wall of the cylinder structure, the honeycomb activated carbon tube is arranged inside the bag cage, and a channel formed by the honeycomb activated carbon tube is a clean flue gas channel; the air blowing port of the back blowing device is over against the connecting port of the dust-removing filter bag; preferably, the filter bag is a two-layer filter bag, the filter bag comprises a dust removal layer and a base cloth layer, the outer layer of the filter bag is the dust removal layer, and the inner layer of the filter bag is the base cloth layer; and the second path of flue gas enters the honeycomb activated carbon tube for second denitration after being subjected to dust removal treatment of the dust removal layer and the base cloth layer in sequence, and the second path of flue gas subjected to second denitration enters the upper box body through the clean flue gas channel.
Furthermore, the sintering flue gas circulation system also comprises an ammonia injection system, a flue gas sealing cover, a first ammonia injection grid, an ammonia supply device and an oxygen supply device; the flue gas sealing cover is arranged above the charge level of the sintering machine, the ammonia injection system is arranged on the circulating flue, and the ammonia injection system is positioned between the dust removal and denitration integrated device and the flue gas sealing cover; the ammonia supply device is used for providing an ammonia source for the first ammonia injection grid and the second ammonia injection grid; the oxygen supply device is arranged on the circulating flue and is positioned between the ammonia injection system and the flue gas sealing cover; the second path of flue gas discharged after being treated by the dedusting and denitration integrated device is divided into two paths of return flue gas and circulating flue gas; the return flue gas is led back into the built-in combustion furnace through the combustion-supporting flue and is used for supporting combustion of coal gas; the circulating flue gas enters a circulating flue, the circulating flue gas sequentially passes through an ammonia injection system and an oxygen supply device and then enters a flue gas sealing cover through a plurality of branches, and the circulating flue gas in the flue gas sealing cover is subjected to denitration treatment for the fourth time in a material layer of the sintering machine, namely, the process of re-sintering the circulating flue gas in the sintering machine is completed.
Further, the discharged flue gas purification system also comprises a sintering main exhaust fan and a chimney; the desulfurization and dust removal integrated device comprises a desulfurization device and a dust removal device, wherein the mixed flue gas enters the desulfurization device for primary desulfurization treatment, and the mixed flue gas after primary desulfurization enters the dust removal device for dust removal treatment and secondary desulfurization treatment; the mixed flue gas is treated by the dust removal device and then discharged into the outer discharge flue, and the mixed flue gas enters the chimney through the action of the sintering main exhaust fan and then is discharged.
Further, the desulfurization device comprises a desulfurization coiled pipe, a first desulfurizer spraying port and a second desulfurizer spraying port which are vertically arranged; the desulfurization coiled pipe at least comprises a lower portion bend and an upper portion bend, one end of the desulfurization coiled pipe is provided with a desulfurization flue gas inlet, the other end of the desulfurization coiled pipe is provided with a desulfurization flue gas outlet, mixed flue gas enters the desulfurization coiled pipe through the desulfurization flue gas inlet, a first desulfurizer spraying inlet is formed in the desulfurization flue gas inlet, a second desulfurizer spraying inlet is formed in the lower portion bend, and the desulfurization flue gas outlet is communicated with the dust removal device; the first desulfurizer spraying port is used for spraying unreacted desulfurization ash, and the second desulfurizer spraying port is used for spraying fresh desulfurizer; and spraying the desulfurized ash and the fresh desulfurizer into a desulfurization coiled pipe to perform first desulfurization treatment, and feeding the mixed flue gas subjected to the first desulfurization into a dust removal device.
Furthermore, the sintering flue gas circulation system also comprises a combustion-supporting fan, a circulating fan, a regulating valve, a first CEMS analyzer, a second CEMS analyzer, a third CEMS analyzer, a pressure detection device and an oxygen concentration analyzer; the combustion-supporting fan is arranged between the dust removal and denitration integrated device and the built-in combustion furnace, and the combustion-supporting fan is arranged on the combustion-supporting flue and used for guiding back the flue gas of the furnace; the circulating fan is arranged between the dedusting and denitration integrated device and the ammonia injection system, and the circulating fan is arranged on the circulating flue and used for accelerating the flow of circulating flue gas; the regulating valve is arranged on the branch and used for regulating the pressure of the flue gas in the flue gas sealing cover; the first CEMS analyzer is arranged on the middle front section flue and is positioned between the gas-gas heat exchanger and the first ammonia injection grid, the second CEMS analyzer is arranged in the dust removal and denitration integrated device and is positioned between the back blowing device and the second ammonia injection grid, and the third CEMS analyzer is arranged on the middle front section flue and is positioned at an outlet of the dust removal and denitration integrated device; the first CEMS analyzer, the second CEMS analyzer and the third CEMS analyzer are used for detecting a first smoke parameter of the second path of smoke and adjusting the spraying amount of the ammonia source in the first ammonia spraying grid and the second ammonia spraying grid according to the first smoke parameter; the pressure detection device is arranged on the smoke sealing cover and used for detecting the pressure of smoke in the smoke sealing cover; the oxygen concentration analyzer is arranged on the smoke sealing cover and used for analyzing oxygen data in the smoke sealing cover.
Further, the oxygen supply device comprises an oxygen buffer tank and an oxygen uniform distributor; the oxygen buffer tank is provided with an oxygen inlet and an oxygen outlet, the input end of the oxygen distributor is connected with the oxygen outlet, and the output end of the oxygen distributor is arranged on the circulating flue; the oxygen supply device adjusts the injection amount of oxygen according to the data of the oxygen concentration analyzer.
Further, the exhaust flue gas purification system also comprises a fourth CEMS analyzer, a fifth CEMS analyzer and a sixth CEMS analyzer; the fourth CEMS analyzer is arranged on the mixing flue and is positioned at the upstream of the first desulfurizer spraying inlet, the fifth CEMS analyzer is arranged on the mixing flue and is positioned between the first desulfurizer spraying inlet and the second desulfurizer spraying inlet, and the sixth CEMS analyzer is arranged on the outer exhaust flue and is positioned between the sintering main exhaust fan and the chimney; and the fourth CEMS analyzer, the fifth CEMS analyzer and the sixth CEMS analyzer are used for detecting a second flue gas parameter of the mixed flue gas and adjusting the spraying amount of the desulfurized ash and the fresh desulfurizer according to the second flue gas parameter.
Further, the desulfurization and dust removal integrated device is an organic combination of a dry or semi-dry desulfurization device and a bag-type dust remover; preferably, the back-blowing device is a pulse back-blowing device; the SCR denitration catalyst layer is in a plate type, a honeycomb type or a corrugated plate type; preferably, the SCR denitration catalyst layer adopts a honeycomb type.
The analysis shows that the embodiment of the integrated treatment device for the sintering flue gas circulation combined full pollutants disclosed by the invention realizes the following technical effects:
(1) compared with the traditional sintering flue gas circulation + desulfurization + dedusting + denitration series technology, the sintering flue gas circulation and full pollutant integrated treatment device realizes the organic combination of the sintering flue gas circulation technology and the desulfurization, dedusting and denitration integrated technology, saves the investment and the operation cost, reduces the occupied area and shortens the construction period;
(2) compared with the traditional flue gas circulation technology, the sintering flue gas circulation and total pollutant integrated treatment device realizes the improvement of the sintering flue gas circulation rate from 20% to 40% through oxygen-enriched sintering flue gas circulation, and effectively avoids the influence of alkali metal in sintering flue gas dust on the quality and yield of sintered ore by adopting a desulfurization and desorption integrated technology;
(3) the sintering flue gas circulation and total pollutant combined integrated treatment device respectively utilizes the built-in combustion furnace, the sintering machine bed temperature window, the dust removal and denitration integrated device and the ammonia injection system to carry out SNCR and SCR reactions at different positions, so that four-time denitration is realized, and NO is greatly reducedxConcentration;
(4) the sintering flue gas circulation and full pollutant integrated treatment device realizes two-stage CO removal reaction by respectively utilizing the material bed temperature windows of the built-in combustion furnace and the sintering machine. The high-concentration CO is changed into valuable, and is recycled, so that the CO concentration is reduced, and the coal gas consumption is saved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. Wherein:
FIG. 1 is a schematic process flow diagram of one embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a desulfurization, dedusting and denitration apparatus according to an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a dedusting and denitrating unit in one embodiment of the present invention;
FIG. 4 is a cross-sectional view taken along line A-A of FIG. 3;
fig. 5 is a cross-sectional view taken in the direction B-B in fig. 3.
Description of reference numerals:
1-sintering machine, 2-flue gas seal hood, 3-pressure detection device, 4-oxygen concentration analyzer, 5-regulating valve, 6-oxygen uniform distributor, 7-oxygen buffer tank, 8-ammonia injection system, 9-gas heat exchanger, 10-first CEMS analyzer, 11-first ammonia injection grid, 12-ammonia supply device, 13-built-in combustion furnace, 14-dust and denitration integrated device, 15-dust and denitration unit, 151-dust removal filter bag, 152-dust removal layer, 153-base cloth layer, 154-bag cage, 155-honeycomb activated carbon tube, 156-clean flue gas channel, 16-back blowing device, 17-second CEMS analyzer, 18-second ammonia injection grid, 19-second denitration unit, 20-upper box body, 21-a third CEMS analyzer, 22-a combustion-supporting fan, 23-a circulating fan, 24-a fourth CEMS analyzer, 25-a first desulfurizer spraying inlet, 26-a fifth CEMS analyzer, 27-a second desulfurizer inlet, 28-a desulfurization and dust removal integrated device, 29-a sintering main exhaust fan, 30-a sixth CEMS analyzer, 31-a chimney, 32-a machine head flue, 33-a middle front section flue, 34-a middle rear section flue, 35-a combustion-supporting flue, 36-a mixed flue, 40-a box body, 41-an assembly plate, 42-a lower box body, 43-a circulating flue, 44-an ash bucket and 45-an outer discharge flue.
Detailed Description
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. The various examples are provided by way of explanation of the invention, and not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. It is therefore intended that the present invention encompass such modifications and variations as fall within the scope of the appended claims and equivalents thereof.
In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are for convenience of description of the present invention only and do not require that the present invention must be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. The terms "connected," "connected," and "disposed" as used herein are intended to be broadly construed, and may include, for example, fixed and removable connections; can be directly connected or indirectly connected through intermediate components; the connection may be a wired electrical connection, a wireless electrical connection, or a wireless communication signal connection, and a person skilled in the art can understand the specific meaning of the above terms according to specific situations.
One or more examples of the invention are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention. As used herein, the terms "first," "second," "third," and "fourth" may be used interchangeably to distinguish one component from another and are not intended to denote the position or importance of the individual components.
As shown in fig. 1 to 5, according to an embodiment of the present invention, there is provided a sintering flue gas circulation and total pollutant integrated treatment device, for treating sintering flue gas exhausted from a sintering machine 1, including a sintering flue gas circulation system and an exhausted flue gas purification system; the head of the sintering machine 1 is communicated with a machine head flue 32, a first path of flue gas flows in the machine head flue 32, the middle front section of the sintering machine 1 is communicated with a middle front section flue 33, a second path of flue gas flows in the middle front section flue 33, the middle rear section of the sintering machine is communicated with a middle rear section flue 34, and a third path of flue gas flows in the middle rear section flue 34; the sintering flue gas circulating system comprises a gas-gas heat exchanger 9, a built-in combustion furnace 13 and a dust removal and denitration integrated device 14; the second path of flue gas passes through the built-in combustion furnace after being subjected to temperature rise treatment of the gas-gas heat exchanger 9, primary denitration is completed at the built-in combustion furnace 13, the second path of flue gas after primary denitration enters the dust-removal and denitration integrated device 14 to complete secondary denitration and tertiary denitration, and the second path of flue gas is discharged by the dust-removal and denitration integrated device and then enters the sintering machine 1 along the circulating flue to participate in the sintering process again; the discharged flue gas purification system comprises a desulfurization and dust removal integrated device 28, the first flue gas and the third flue gas which is subjected to heat exchange and temperature reduction through a gas-gas heat exchanger 9 are converged into a mixed flue gas and enter the desulfurization and dust removal integrated device 28 through a mixed flue 36 for desulfurization and dust removal treatment, and the mixed flue gas after the desulfurization and dust removal treatment is discharged from a discharged flue 45.
In the above embodiment, the sintering flue gas circulation and total pollutant combined integrated treatment device includes a sintering flue gas circulation system and an externally-discharged flue gas purification system. The bottom of the sintering machine 1 is provided with air boxes, outlets of the air boxes are connected with a main flue of the sintering machine 1, sintering flue gas in the air box of the sintering machine 1 is divided into first flue gas, second flue gas and third flue gas, wherein the first flue gas is flue gas at the head of the sintering machine 1 (1-3 # air box flue gas and low-temperature flue gas), and the second flue gas is flue gas at the front section of the sintering machine 1 (corresponding to 4-13 # air box flue gas, high CO and NO)xFlue gas), the second flue gas is used as a cold medium, the third flue gas is flue gas at the rear section of the sintering machine 1 (corresponding to No. 14-22 bellows flue gas and high-temperature flue gas), and the third flue gas is used as a hot medium and is provided with corresponding flues respectively. The head of the sintering machine 1 is communicated with a machine head flue 32, the first path of flue gas flows in the machine head flue 32, the middle front section of the sintering machine 1 is communicated with a middle front section flue 33, the second path of flue gas flows in the middle front section flue 33, the middle rear section of the sintering machine 1 is communicated with a middle rear section flue 34, and the third path of flue gas flows in the middle rear section flue 34. In addition, all devices, equipment and instruments of the sintering flue gas circulation combined full-pollutant integrated treatment device are communicated through flues. On the premise of not influencing the quality of the sinter, the second path of flue gas is circulated back to the sintering machine 1 through a sintering flue gas circulation system for hot air sintering, and the first path of flue gas and the third path of flue gas enter a downstream discharged flue gas purification system through a main flue of the sintering machine 1. The sintering flue gas circulating system comprises a gas-gas heat exchanger 9, a built-in combustion furnace 13 and a dust removal and denitration integrated device 14. The temperature of the second path of flue gas is increased from 100 ℃ to about 180 ℃ after the temperature of the second path of flue gas is increased through the heat exchange of the gas-gas heat exchanger 9, and then the first denitration and the first CO removal treatment of the second path of flue gas are completed at the built-in combustion furnace 13. The second flue gas after the first denitration enters the dust removal and denitration integrated device 14 to complete the second denitration and the third denitration, and the second flue gas is subjected to denitration treatment twice in the dust removal and denitration integrated device 14, compared with the first denitrationAnd (3) carrying out a nitration reaction, wherein the denitration efficiency is ensured and ammonia escape is reduced by setting two-stage denitration reaction and spraying ammonia in stages. The second path of flue gas is discharged by the dust removal and denitration integrated device 14 and then enters the sintering machine 1 along the circulating flue 43 to participate in the sintering process again. The discharged flue gas purification system comprises a desulfurization and dust removal integrated device 28, the first flue gas and the third flue gas subjected to heat exchange and temperature reduction by the gas-gas heat exchanger 9 are converged into a mixed flue gas to enter a mixed flue 36, wherein after the third flue gas is subjected to heat exchange by the gas-gas heat exchanger 9, the temperature of the third flue gas is reduced from 280 ℃ to about 200 ℃, and the effective utilization of the heat of the high-temperature flue gas is realized. The mixed flue gas enters the integrated desulfurization and dust removal device 28 to complete desulfurization and dust removal treatment and then is discharged, the integrated desulfurization and dust removal device 28 can perform desulfurization and dust removal treatment on the flue gas, and preferably, the integrated desulfurization and dust removal device 28 is an organic combination of a dry-method or semi-dry-method desulfurization device and a bag-type dust remover. Compared with the common sintering flue gas pollutant treatment technology and the traditional sintering flue gas circulation technology, the sintering flue gas circulation combined full-pollutant integrated treatment device has obvious advantages and mainly comprises: compared with the traditional sintering flue gas circulation + desulfurization + dedusting + denitration series technology, the sintering flue gas circulation and all-pollutant integrated treatment device realizes the organic combination of the sintering flue gas circulation technology and the desulfurization, dedusting and denitration integrated technology, saves the investment and the operation cost, reduces the occupied area and shortens the construction period; compared with the traditional flue gas circulation technology, the sintering flue gas circulation and all-pollutant integrated treatment device realizes the improvement of the sintering flue gas circulation rate from 20% to 40% through oxygen-enriched sintering flue gas circulation; by adopting a desulfurization and desorption integrated technology, the influence of alkali metal in the sintering flue gas dust on the quality and the yield of the sintered ore is effectively avoided; thirdly, the sintering flue gas circulation combined full pollutant integrated treatment device respectively utilizes the built-in combustion furnace 13 and the dust removal and denitration integrated device to generate SNCR and SCR reactions at different positions, so as to realize multiple denitration and greatly reduce NOxConcentration; fourthly, the sintering flue gas circulation and full pollutant integrated treatment device can realize two-stage CO removal reaction. The high-concentration CO is changed into valuable, and is recycled, so that the CO concentration is reduced, and the coal gas consumption is saved.
The common heating furnace is that a heating hearth is arranged around a flue, gas generates high-temperature gas after being combusted in the heating hearth, the high-temperature gas enters the flue and is mixed with upstream flue gas to achieve the purpose of heating the flue gas, an igniter, a combustion-supporting flue gas pipeline and a gas pipeline of the back-combustion furnace in the built-in combustion furnace 13 are all inserted into the flue, the flue gas is ignited, combusted and heated in the flue, and the igniter can adopt a plasma ignition mode or other ignition modes. The in-line furnace 13 system has the following advantages: firstly, coal gas is combusted in the flue, and compared with combustion in a hearth outside the flue, the heat dissipation of combustion can be greatly reduced; secondly, the average concentration of CO in the second path of flue gas is 10000mg/m3While the average CO concentration in the windboxes of the sintering machine 1 was only 5300mg/m3. The central temperature of gas combustion is about 1200 ℃, CO in the second path of flue gas can be easily ignited, CO is combusted to release heat, on one hand, the pollutant components are changed into valuable, the gas consumption is saved, on the other hand, the CO concentration is also reduced, and according to estimation, the CO concentration can be reduced by about 20%, and the process is called as first CO removal. Thirdly, the dioxin is utilized to carry out combustion reaction in the gas combustion center, and part of the dioxin can also be removed.
Preferably, as shown in fig. 1 to 5, in an embodiment of the present invention, the dust-removing and denitration integrated apparatus 14 includes a plurality of dust-removing and denitration units 15, a blowback apparatus 16, a second ammonia injection grid 18, a second denitration unit 19, a box 40, an ash bucket 44 and an assembly plate 41; the fitting plate 41 is provided in the case 40, and divides the case 40 into a lower case 42 and an upper case 20; the plurality of dust removal and denitration units 15 are arranged in the lower box body 42, a honeycomb-shaped activated carbon pipe 155 is arranged in each dust removal and denitration unit 15, an SCR denitration catalyst is loaded in the honeycomb-shaped activated carbon pipe 155, and the honeycomb-shaped activated carbon pipe 155 is a first denitration unit; the back blowing device 16, the second ammonia injection grid 18 and the second denitration unit 19 are all arranged in the upper box body 20, the back blowing device 16 is arranged above the assembling plate 41, and the blowing port of the back blowing device 16 is over against the dedusting and denitration unit 15; the ash bucket 44 is connected with the lower end of the lower box body 42, the lower end of the lower box body 42 is open, and the ash bucket 44 is communicated with the lower box body 42; the second denitration unit 19 is arranged above the back flushing device 16, and an SCR denitration catalyst layer is arranged in the second denitration unit 19; the second ammonia injection grid 18 is arranged between the second denitration unit 19 and the blowback device 16, a nozzle of the second ammonia injection grid 18 faces the dust removal denitration unit 15, the second ammonia injection grid 18 is used for injecting an ammonia source before the flue gas reaches the second denitration unit 19, preferably, the ammonia source is injected into the flue gas at the outlet of the dust removal denitration unit 15, and the ammonia source is ammonia gas or ammonia water and the like. The second flue gas enters the lower box body 42, the dedusting treatment and the second denitration treatment are completed at the first denitration unit, the second flue gas enters the upper box body 20 after being treated by the first denitration unit, the third denitration is completed in the second denitration unit 19, and the second flue gas after being subjected to the third denitration is discharged from the upper box body 20.
In the above embodiment, the integrated dedusting and denitrating device 14 is a box-type structure, and the dedusting and denitrating unit 15, the blowback device 16, the second ammonia injection grid 18 and the second denitrating unit 19 are all disposed in the box 40. A honeycomb activated carbon tube 155 is arranged in the dedusting and denitration unit 15, an SCR denitration catalyst is loaded in the honeycomb activated carbon tube 155, the honeycomb activated carbon tube 155 is a first denitration unit, and the second path of flue gas is subjected to second denitration at the first denitration unit. The blowback device 16 is a device for performing blowback, preferably, the blowback device 16 adopts a pulse blowback device, the pulse blowback device is installed above the assembly plate 41, the blowing port of the blowback device 16 is right opposite to the dust removal and denitration unit 15, most of dust can be removed by the dust removal and denitration unit 15, the dust on the dust removal and denitration unit 15 can fall into the dust hopper 44 below through the blowback device 16, wherein the number of the dust hopper 44 is plural. An SCR denitration catalyst layer, referred to as a second denitration unit 19, is disposed above the blowback device 16, and the SCR denitration catalyst layer may be a plate type, a honeycomb type, or a corrugated plate type, and preferably, the SCR denitration catalyst layer is a honeycomb type. The second ammonia injection grid 18 is arranged between the second denitration unit 19 and the blowback device 16, the second ammonia injection grid 18 is used for uniformly injecting ammonia sources into the flue gas subjected to the second denitration, wherein the second ammonia injection grid 18 can inject ammonia gas and other ammonia sources such as ammonia water. A reducing agent is provided for the denitration reaction of the second denitration unit 19. The second path of flue gas enters a honeycomb activated carbon tube 155 of the dedusting and denitration unit 15, and the honeycomb activated carbon has large specific surface area,The microporous porous structure, high adsorption capacity, good catalyst dispersibility, good chemical stability, excellent adsorption performance and the like, so that NO in the second path of flue gasx、NH3The catalyst is easy to be fully adsorbed on the surface of the SCR denitration catalyst and can generate a second denitration reaction. The second flue gas after the second denitration enters the upper box body 20 to prevent NO in the flue gasxThe reaction in the dedusting and denitration unit 15 is incomplete, so that a second ammonia-spraying grid 18 and a second denitration unit 19 are sequentially arranged in the upper box body 20 from bottom to top, a third denitration reaction occurs at the second denitration unit 19, and the second flue gas after the third denitration is discharged from the upper box body 20. Dust removal denitration integrated device 14 has improved denitration efficiency through setting up two-stage denitration reaction.
Preferably, as shown in fig. 2 to 5, in one embodiment of the present invention, the dust-removal denitration unit 15 includes a dust-removal filter bag 151, a bag cage 154, and a clean flue gas passage 156; the dust removal filter bag 151 is of a cylinder structure, the dust removal filter bag 151 is composed of 1-4 layers of filter bags, a bag cage 154 is supported on the inner wall of the cylinder structure, a honeycomb activated carbon tube 155 is arranged inside the bag cage 154, and a channel formed by the honeycomb activated carbon tube 155 is a clean flue gas channel 156; the blowing port of the back blowing device 16 is over against the connecting port of the dust-removing filter bag 151; preferably, the filter bag 151 is a 2-layer filter bag, the filter bag 151 comprises a dust removal layer 152 and a base cloth layer 153, the outer layer of the filter bag 151 is the dust removal layer 152, and the inner layer of the filter bag 151 is the base cloth layer 153; the second flue gas passes through the dedusting treatment of the dedusting layer 152 and the base cloth layer 153 in sequence, enters the honeycomb activated carbon tube 155 for the second denitration, and enters the upper box body 20 through the clean flue gas channel 156 after the second denitration.
In the above embodiment, the dust bag 151 has a cylindrical structure, the bag cage 154 is supported on the inner wall of the cylindrical structure, the honeycomb activated carbon tube 155 is installed inside the bag cage 154, and the channel formed by the honeycomb activated carbon tube 155 is the clean flue gas channel 156. The dust removal filter bag 151 and the honeycomb-shaped activated carbon pipe 155 are of split structures, the dust removal filter bag 151 or the honeycomb-shaped activated carbon pipe 155 can be independently replaced according to the use condition, the dust removal unit and the denitration unit are designed in a split mode, the use and the maintenance are more convenient, and the problem that the service lives of the dust removal function and the denitration function are inconsistent is effectively solved. The dust filter bag 151 is composed of 1 to 4 layers, and when the number of layers of the filter bag is too small and too thin, the filter bag is easily worn and broken in use, and when the number of layers is too large, the pressure loss is too large, which is not beneficial to system energy conservation. Preferably, the filter bag 151 is a 2-layer filter bag, the filter bag 151 includes a dust removal layer 152 and a base fabric layer 153, an outer layer of the filter bag 151 is the dust removal layer 152, and an inner layer of the filter bag 151 is the base fabric layer 153. The dust removal layer 152 is made of carbon fiber, polyphenylene sulfide fiber and doped with ultrafine carbon fiber, is relatively compact and is used for removing dust and removing PM 2.5; the base cloth layer 153 is woven of carbon fibers and has a lower density than the dust removal layer for supporting and maintaining air permeability. The carbon fiber has the advantages of small density, light weight, good chemical corrosion resistance, fatigue resistance, long service life, high strength, high modulus, good thermal expansion coefficient, self-lubrication, wear resistance and the like. The carbon fiber is added into the filter material, so that the wear resistance, toughness and strength of the filter bag can be enhanced, the weight of the filter bag is reduced, the load of a dust remover is reduced, and the service life of the filter bag is prolonged. Before the second flue gas enters the dust removal and denitration integrated device 14, the temperature of the second flue gas is raised to 220-240 ℃, after the second flue gas enters the dust removal and denitration unit 15, the second flue gas enters the honeycomb-shaped activated carbon tube 155 for a second denitration reaction through the dust removal treatment of the dust removal layer 152 and the base cloth layer 153, and the second flue gas after the second denitration enters the upper box body 20 through the purified flue gas channel 156.
Preferably, as shown in fig. 1 and fig. 2, in an embodiment of the present invention, the sintering flue gas circulation system further includes an ammonia injection system 8, a flue gas sealing cover 2, a first ammonia injection grid 11, an ammonia supply device 12 and an oxygen supply device; the flue gas sealing cover 2 is arranged above the charge level of the sintering machine 1, the ammonia injection system 8 is arranged on the circulating flue 43, and the ammonia injection system 8 is positioned between the dedusting and denitration integrated device 14 and the flue gas sealing cover 2; the first ammonia injection grid 11 is arranged between the gas-gas heat exchanger 9 and the built-in combustion furnace 13, the ammonia supply device 12 is respectively communicated with the first ammonia injection grid 11 and the second ammonia injection grid 18, and the ammonia supply device 12 is used for providing ammonia sources for the first ammonia injection grid 11 and the second ammonia injection grid 18; the oxygen supply device is arranged on the circulating flue and is positioned between the ammonia injection system 8 and the flue gas sealing cover 2; the second path of flue gas discharged after being treated by the dedusting and denitration integrated device 14 is divided into two paths of return flue gas and circulating flue gas; the return flue gas is led back to the built-in combustion furnace 13 through the combustion-supporting flue 35 and is used for gas combustion-supporting; the circulating flue gas enters the circulating flue 43, the circulating flue gas sequentially passes through the ammonia injection system 8 and the oxygen supply device and then enters the flue gas sealing cover 2 through a plurality of branches, the circulating flue gas in the flue gas sealing cover 2 completes the fourth denitration treatment in the material layer of the sintering machine, and the circulating flue gas completes the re-sintering process in the sintering machine 1.
In the above embodiment, the flue gas sealed hood 2 is arranged above the material level of the sintering machine 1, the first ammonia injection grid 11 is arranged between the gas-gas heat exchanger 9 and the built-in combustion furnace 13, the first ammonia injection grid 11 is arranged at the upstream of the built-in combustion furnace 13, and the purpose is mainly to generate a temperature window of over 900 ℃ by using gas combustion and generate a part of NO at the built-in combustion furnace 13xTo accomplish the first denitrification. The second path of flue gas discharged from the dedusting and denitration integrated device 14 is divided into two paths of return flue gas and circulating flue gas; wherein, the return flue gas is led back to the built-in combustion furnace for combustion-supporting of the gas; the circulating flue gas is introduced into a subsequent flue, sequentially passes through the ammonia injection system 8 and the oxygen supplementing device, then enters the flue gas sealing cover 2 by a plurality of branches, and finally enters a sinter bed of the sintering machine 1 to participate in the sintering process again. The ammonia injection system 8 is used for uniformly injecting ammonia sources such as ammonia gas or ammonia water into the circulating flue gas. In the present embodiment, the ammonia injection system 8 replenishes the circulation flue 43 with NH3To make NO containedxThe circulating flue gas is mixed with NH in the sinter bed3SNCR reaction is carried out to carry out the fourth denitration treatment and further remove NOx. The SNCR denitration reaction temperature range is 900-1100 ℃, is consistent with the sintered ore bed temperature (1000-1100 ℃) and has a reaction temperature window (sintering machine bed temperature window). In addition, in the sinter bed, a combustion reaction of a part of CO also occurs, and this process is called secondary CO removal. In addition, a part of dioxin can be removed by utilizing the combustion reaction of the dioxin in the high-temperature sinter bed. The sintering flue gas circulation and full pollutant integrated treatment device respectively utilizes a built-in combustion furnace 13, a sintering machine material bed temperature window and a dust removal and denitration integrated device 14,SNCR and SCR reactions occur at different positions, so that four-time denitration is realized, and NO is greatly reducedxAnd (4) concentration.
Preferably, as shown in fig. 1, in an embodiment of the present invention, the exhaust flue gas purification system further comprises a sintering main exhaust fan 29 and a chimney 31; the desulfurization and dust removal integrated device 28 comprises a desulfurization device and a dust removal device, the mixed flue gas enters the desulfurization device for primary desulfurization treatment, and the mixed flue gas after primary desulfurization enters the dust removal device for dust removal treatment and secondary desulfurization treatment; the mixed flue gas is treated by a dust removal device and then discharged into an external exhaust flue 45, and enters a chimney 31 through the action of a sintering main exhaust fan 29 and then is discharged.
Preferably, the desulfurization device comprises a desulfurization coiled pipe, a first desulfurizer spray inlet 25 and a second desulfurizer spray inlet 27 which are vertically arranged, the desulfurization coiled pipe at least comprises a lower bending part and an upper bending part, one end of the desulfurization coiled pipe is provided with a desulfurization flue gas inlet, the other end of the desulfurization coiled pipe is provided with a desulfurization flue gas outlet, mixed flue gas enters the desulfurization coiled pipe through the desulfurization flue gas inlet, the first desulfurizer spray inlet 25 is arranged on the desulfurization flue gas inlet, the second desulfurizer spray inlet 27 is arranged at the lower bending part, and the desulfurization flue gas outlet is communicated with the dust removal device; the first desulfurizer spraying port 25 is used for spraying unreacted desulfurization ash, and the second desulfurizer spraying port 27 is used for spraying fresh desulfurizer; and spraying the desulfurized ash and the fresh desulfurizer into a desulfurization coiled pipe to perform first desulfurization treatment, and feeding the mixed flue gas subjected to the first desulfurization into a dust removal device.
In the above embodiment, the first flue gas and the third flue gas which is subjected to heat exchange and temperature reduction by the gas-gas heat exchanger 9 are merged into a single mixed flue gas before the desulfurization and dust removal integrated device 28, wherein the desulfurizing agent is sprayed into the desulfurization device in two ways to perform desulfurization reaction, and the unreacted desulfurization ash is sprayed from the first desulfurizing agent spraying inlet 25 and the second desulfurizing agent spraying inlet 26 respectively, and the fresh desulfurizing agent is sprayed from the second desulfurizing agent spraying inlet 26. The first desulfurizing agent injection port 25 is disposed upstream of the second desulfurizing agent injection port 27, i.e., the desulfurized fly ash injection port is disposed in front of the fresh desulfurizing agent inlet, in order to make the raw flue gas high in concentrationSO2Firstly, the sulfur-containing gas is contacted with desulfurized fly ash to remove a part of SO2Then part of the desulfurized flue gas is contacted with a fresh desulfurizer, which is beneficial to increasing SO2And (4) removing efficiency. Wherein the desulfurization ash contains effective desulfurization components mainly comprising Na2CO3, the mass percent is about 20-30%; the effective desulfurization component of the fresh desulfurizer is mainly NaHCO3The mass percentage is more than about 99.8 percent. Spraying desulfurized ash and fresh desulfurizing agent into the mixed flue gas, NaHCO3Is instantaneously decomposed into countless high-activity and high-porosity Na2CO3Particles of these Na2CO3SO in particles and flue gas2Rapid desulfurization chemical reaction occurs, 75-80% of the desulfurization reaction is completed at this stage, and the above desulfurization reaction completed in the apparatus is the first desulfurization reaction. In the flue before desulfurization dust collector 28, the mixed flue gas after the first step desulfurization reaction gets into the dust removal region, and in this region, the mixed flue gas loops through the dust removal layer of filter bag, because the dust removal layer is more compact, therefore the filter bag can get rid of most dust, through the blowback device, falls into the ash bucket in the below. The filter cake formed on the surface of the filter bag mainly comprises desulfurization reaction products, unreacted desulfurizer and fly ash, and residual SO in the flue gas2The desulfurization reaction is carried out by adsorbing on the filter cake, which is called as the second step desulfurization reaction. Typically 15-20% of the contaminants will react in the bag-type dust collector by making the high concentration of SO in the raw flue gas2Firstly, the sulfur-containing material reacts with desulfurized fly ash to remove a part of SO2Then unreacted low concentration SO2Then reacts with fresh desulfurizer, which is beneficial to increasing SO2The overall removal efficiency. The mixed flue gas after the second desulfurization treatment is discharged from the desulfurization and dust removal integrated device 28, enters a chimney 31 through the action of a main sintering exhaust fan 29 and is discharged.
Preferably, as shown in fig. 1 to 5, in an embodiment of the present invention, the sintering flue gas circulation system further includes a combustion fan 22, a circulation fan 23, a regulating valve 5, a first CEMS analyzer 10, a second CEMS analyzer 17, a third CEMS analyzer 21, a pressure detection device 3, and an oxygen concentration analyzer 4; the combustion-supporting fan 22 is arranged between the dust removal and denitration integrated device 14 and the built-in combustion furnace 13, and the combustion-supporting fan 22 is arranged on the combustion-supporting flue 35 and used for introducing back to the furnace flue gas; the circulating fan 23 is arranged between the dedusting and denitration integrated device 14 and the ammonia injection system 8, and the circulating fan 23 is arranged on the circulating flue 43 and used for providing power for the circulating flue gas to return to the material layer of the sintering machine; the regulating valve 5 is arranged on the branch and used for regulating the pressure of the flue gas in the flue gas sealing cover 2; the first CEMS analyzer 10 is arranged on the middle front section flue 33 and is positioned between the gas-gas heat exchanger 9 and the first ammonia injection grid 11, the second CEMS analyzer 17 is arranged in the dust removal and denitration integrated device 14 and is positioned between the back blowing device 16 and the second ammonia injection grid 18, and the third CEMS analyzer 21 is arranged on the middle front section flue 33 and is positioned at an outlet of the dust removal and denitration integrated device 14; the first CEMS analyzer 10, the second CEMS analyzer 17 and the third CEMS analyzer 21 are used for detecting a first flue gas parameter of the second flue gas and adjusting the spraying amount of the ammonia source in the first ammonia spraying grid 11 and the second ammonia spraying grid 18 according to the first flue gas parameter; the pressure detection device 3 is arranged on the flue gas sealing cover 2 and is used for detecting the pressure of flue gas in the flue gas sealing cover 2; the oxygen concentration analyzer 4 is arranged on the flue gas sealing cover 2 and used for analyzing oxygen data in the flue gas sealing cover 2.
In the above embodiment, the regulating valve 5 is disposed between the oxygen supply device and the flue gas sealed housing 2, and is used for regulating the pressure of the flue gas in the flue gas sealed housing 2. Circulating flue gas passes through the oxygen supply device and then enters the flue gas sealing cover 2 through a plurality of branches, and in order to enable the circulating flue gas to be uniformly distributed in the flue gas sealing cover 2, the circulating flue gas is introduced into the flue gas sealing cover 2 through 4-8 branch pipelines (not limited to 4-8 pipelines, and the actual quantity is determined according to the scale of a sintering machine and the actual working condition). Preferably, in the embodiment of the present invention, the circulating flue gas is introduced into the flue gas sealing cover 2 by 4 branch pipelines, the 4 branch pipelines are respectively provided with the regulating valves 5, and the opening of the regulating valves is adjusted according to the differences of the air permeability and the air demand of the material layer in different areas, so that the flue gas pressure is kept stable in the flue gas sealing cover 2, and the micro-negative pressure state is maintained, thereby preventing the flue gas from leaking. In order to ensure real-time monitoring of the flue gas pressure, four pressure detection devices 3 are arranged on the flue gas sealing cover 2. The number of the pressure detection devices 3 is not limited to four, and is consistent with the number of the branch pipelines. A first CEMS analyzer 10, a second CEMS analyzer 17 and a second CEMS analyzerThree CEMS analyzers 21 for detecting the temperature, pressure, flow, dust concentration and NO of flue gas before and after the dust removal and denitration integrated device 14xConcentration and the like, and adjusting the injection amount of the ammonia source in the first ammonia injection grid 11 and the second ammonia injection grid 18 according to the first flue gas parameter so as to achieve the optimal ammonia/nitrogen molar ratio. The dust removal and denitration integrated device 14 is provided with two-stage denitration reaction and graded ammonia spraying, ammonia is sprayed in a first stage in a front flue of an inlet of the dust removal and denitration device 14, ammonia is sprayed in a second stage in front of an SCR denitration catalyst layer, and the ammonia spraying amount is adjusted and accurately controlled according to test data of the first CEMS analyzer 10, the second CEMS analyzer 17 and the third CEMS analyzer 21, so that ammonia escape is reduced.
Preferably, as shown in fig. 1, in one embodiment of the present invention, the oxygen supply apparatus includes an oxygen buffer tank 7 and an oxygen sparger 6; an oxygen inlet and an oxygen outlet are arranged on the oxygen buffer tank 7, the input end of the oxygen distributor 6 is connected with the oxygen outlet, and the output end of the oxygen distributor is arranged on the circulating flue 43; the oxygen supply apparatus adjusts the amount of oxygen to be injected based on the data from the oxygen concentration analyzer 4. An oxygen supplementing device is arranged for ensuring that the oxygen content of the flue gas in the flue gas sealing cover 2 is more than 18 percent (when the oxygen content is more than 18 percent, the sintering production is not influenced). And adjusting the oxygen injection amount through PID according to the data of an oxygen concentration analyzer 4 arranged on the flue gas seal cover 2. The pure oxygen is used for oxygen supplement, so that the flue gas circulation rate can reach more than 40 percent, and is much higher than the 20 percent flue gas circulation rate of the traditional flue gas circulation process.
Preferably, as shown in fig. 1, in one embodiment of the present invention, the effluent flue gas cleaning system further comprises a fourth CEMS analyzer 24, a fifth CEMS analyzer 26, and a sixth CEMS analyzer 30; the fourth CEMS analyzer 24 is arranged on the mixing flue 36 and is positioned at the upstream of the first desulfurizer spraying port 25, the fifth CEMS analyzer 26 is arranged on the mixing flue 36 and is positioned between the first desulfurizer spraying port 25 and the second desulfurizer spraying port 27, and the sixth CEMS analyzer 30 is arranged on the outer discharge flue 45 and is positioned between the sintering main exhaust fan 29 and the chimney 31; the fourth CEMS analyzer 24, the fifth CEMS analyzer 26 and the sixth CEMS analyzer 30 are used for detecting a second flue gas parameter of the mixed flue gas and adjusting the smoke removal according to the second flue gas parameterThe sprayed amount of the sulfur ash and the fresh desulfurizer. The fourth CEMS analyzer 24, the fifth CEMS analyzer 26 and the sixth CEMS analyzer 30 are used for detecting the temperature, the pressure, the flow, the dust concentration and the SO in the flue gas before and after the integrated desulfurization and dust removal device 282Concentration and O2And (4) the concentration of the second flue gas parameter is obtained, and the spraying amount of the desulfurized ash, the fresh desulfurizer and the oxygen is adjusted according to the second flue gas parameter.
From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects:
(1) compared with the traditional sintering flue gas circulation + desulfurization + dedusting + denitration series technology, the sintering flue gas circulation and full pollutant integrated treatment device realizes the organic combination of the sintering flue gas circulation technology and the desulfurization, dedusting and denitration integrated technology, saves the investment and the operation cost, reduces the occupied area and shortens the construction period;
(2) compared with the traditional flue gas circulation technology, the sintering flue gas circulation and total pollutant integrated treatment device realizes the improvement of the sintering flue gas circulation rate from 20% to 40% through oxygen-enriched sintering flue gas circulation, and effectively avoids the influence of alkali metal in sintering flue gas dust on the quality and yield of sintered ore by adopting a desulfurization and desorption integrated technology;
(3) the sintering flue gas circulation and all-pollutant integrated treatment device respectively utilizes the built-in combustion furnace 13, the sintering machine material bed temperature window and the dust and denitration integrated device 14 to generate SNCR and SCR reactions at different positions, so that four-time denitration is realized, and NO is greatly reducedxConcentration;
(4) the sintering flue gas circulation and full pollutant integrated treatment device realizes two-stage CO removal reaction by respectively utilizing the built-in combustion furnace 13 and the material bed temperature window of the sintering machine. The high-concentration CO is changed into valuable, and is recycled, so that the CO concentration is reduced, and the coal gas consumption is saved.
Simultaneously, this sintering flue gas circulation unites full pollutant integration treatment device has solved a series of difficult problems that traditional dust removal denitration integrated device faced, specifically as follows:
(1) the dust removal unit and the denitration unit in the dust removal and denitration unit 15 in the sintering flue gas circulation and all-pollutant integrated treatment device are designed in a split mode, so that the device is more convenient to use and maintain, the problem that the service lives of the dust removal function and the denitration function are inconsistent is fundamentally solved, the service time is effectively prolonged, and the maintenance cost is saved;
(2) the filter bag 151 comprises a dust removal layer 152 and a base cloth layer 153, wherein the dust removal layer 152 is made of carbon fibers, polyphenylene sulfide fibers and doped with ultrafine carbon fibers, is relatively compact and is used for removing dust and removing PM 2.5; the base cloth layer 153 is woven of carbon fibers and has a lower density than the dust removal layer for supporting and maintaining air permeability. The carbon fibers are doped into the filter bag 151, so that the wear resistance, toughness and strength of the cloth bag are improved, the service life is prolonged, and the cost is saved;
(3) the sintering flue gas circulation and all-pollutant integrated treatment device is provided with two-stage ammonia spraying and two-stage denitration reaction, the ammonia spraying amount is accurately controlled, the denitration efficiency is ensured, and ammonia escape is reduced;
(4) the denitration module adopts a mode that the honeycomb-shaped activated carbon tube 155 is loaded with the low-temperature denitration catalyst, so that hazardous waste treatment is facilitated, and after the 15 bodies of the dust removal denitration unit are scrapped, the filter bag 154 can be treated according to normal waste; the honeycomb activated carbon pipe 155 can be treated in a combustion mode after being scrapped, V, W, Ti metal can be recovered from combustion ash, and the honeycomb activated carbon pipe can be recycled in a reasonable mode, so that pollution and waste are avoided, and the recycling of elements is realized.
In addition, the sintering flue gas circulation technology in the sintering flue gas circulation and all-pollutant integrated treatment device adopts pure O2The oxygen content of the circulating flue gas is supplemented, the emission reduction amount of the flue gas can be greatly improved, and the flue gas can be automatically adjusted according to the actual condition; the desulfurized fly ash and the fresh desulfurizer are sprayed into the desulfurization reaction device in a grading manner, so that the utilization rate and the desulfurization efficiency of the desulfurized fly ash are improved; two-stage ammonia injection and two-stage denitration reaction are carried out, the ammonia injection amount is accurately controlled, the denitration efficiency is ensured, and ammonia escape is reduced; the honeycomb activated carbon tube is used as a low-temperature denitration catalyst carrier, is favorable for improving the specific surface area of the carrier, has uniform catalyst loading degree, is favorable for waste treatment, and promotes the resource utilization of metal elements.
The above is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made to the present invention by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A sintering flue gas circulation combined full pollutant integrated treatment device is used for treating sintering flue gas discharged by a sintering machine and is characterized by comprising a sintering flue gas circulation system and an externally discharged flue gas purification system;
the head of the sintering machine is communicated with a machine head flue, a first path of flue gas flows in the machine head flue, the middle front section of the sintering machine is communicated with a middle front section flue, a second path of flue gas flows in the middle front section flue, the middle rear section of the sintering machine is communicated with a middle rear section flue, and a third path of flue gas flows in the middle rear section flue;
the sintering flue gas circulating system comprises a gas-gas heat exchanger, a built-in combustion furnace and a dust removal and denitration integrated device;
the second path of flue gas is subjected to temperature rise treatment by the gas-gas heat exchanger and then passes through the built-in combustion furnace, primary denitration is completed at the built-in combustion furnace, the second path of flue gas subjected to the primary denitration enters the dust-removal and denitration integrated device to complete secondary denitration and third denitration, and the second path of flue gas is discharged by the dust-removal and denitration integrated device and then enters the sintering machine along a circulating flue to participate in the sintering process again;
the outer exhaust flue gas purification system comprises a desulfurization and dust removal integrated device, the first path of flue gas and the third path of flue gas subjected to heat exchange and temperature reduction by the gas-gas heat exchanger are converged into a path of mixed flue gas and enter the desulfurization and dust removal integrated device through a mixed flue to be subjected to desulfurization and dust removal treatment, and the mixed flue gas after the desulfurization and dust removal treatment is discharged from the outer exhaust flue.
2. The integrated treatment device for the sintering flue gas circulation combined total pollutants as in claim 1, wherein the integrated dedusting and denitration device comprises a plurality of dedusting and denitration units, a back-blowing device, a second ammonia injection grid, a second denitration unit, a box body, an ash hopper and an assembly plate;
the assembly plate is arranged in the box body and divides the box body into a lower box body and an upper box body;
the plurality of dust removal and denitration units are arranged in the lower box body, a honeycomb-shaped activated carbon tube is arranged in each dust removal and denitration unit, an SCR denitration catalyst is loaded in each honeycomb-shaped activated carbon tube, and each honeycomb-shaped activated carbon tube is a first denitration unit;
the back blowing device, the second ammonia spraying grid and the second denitration unit are all arranged in the upper box body, the back blowing device is arranged above the assembling plate, and a blowing port of the back blowing device is over against the dedusting and denitration unit;
the ash hopper is connected with the lower end of the lower box body, the lower end of the lower box body is open, and the ash hopper is communicated with the lower box body;
the second denitration unit is arranged above the back flushing device, and an SCR denitration catalyst layer is arranged in the second denitration unit;
the second ammonia injection grid is arranged between the second denitration unit and the back blowing device, and a nozzle of the second ammonia injection grid faces the dust removal denitration unit;
and the second flue gas enters the lower box body, the dedusting treatment and the second denitration treatment are completed at the first denitration unit, the second flue gas enters the upper box body after being treated by the first denitration unit, the third denitration is completed in the second denitration unit, and the second flue gas after being subjected to the third denitration is discharged from the upper box body.
3. The integrated treatment device for the sintering flue gas circulation combined total pollutants as claimed in claim 2, wherein the dust removal and denitration unit comprises a dust removal filter bag, a bag cage and a clean flue gas channel;
the dust removal filter bag is of a cylinder structure and consists of one to four filter bags, the bag cage is supported on the inner wall of the cylinder structure, the honeycomb activated carbon tube is arranged inside the bag cage, and a channel formed by the honeycomb activated carbon tube is the clean flue gas channel;
the air blowing port of the back blowing device is over against the connecting port of the dust-removing filter bag;
preferably, the filter bag is a two-layer filter bag, the filter bag comprises a dust removal layer and a base cloth layer, the outer layer of the filter bag is the dust removal layer, and the inner layer of the filter bag is the base cloth layer;
and the second path of flue gas enters the honeycomb-shaped activated carbon tube for second denitration after the dedusting treatment of the dedusting layer and the base cloth layer in sequence, and the second path of flue gas after the second denitration enters the upper box body through the clean flue gas channel.
4. The integrated treatment device for the sintering flue gas circulation combined with the total pollutants as claimed in claim 2, wherein the sintering flue gas circulation system further comprises an ammonia injection system, a flue gas sealing cover, a first ammonia injection grid, an ammonia supply device and an oxygen supply device;
the flue gas sealing cover is arranged above the charge level of the sintering machine, the ammonia injection system is arranged on the circulating flue, and the ammonia injection system is positioned between the dust removal and denitration integrated device and the flue gas sealing cover;
the first ammonia injection grid is arranged between the gas-gas heat exchanger and the built-in combustion furnace, the ammonia supply device is respectively communicated with the first ammonia injection grid and the second ammonia injection grid, and the ammonia supply device is used for providing an ammonia source for the first ammonia injection grid and the second ammonia injection grid;
the oxygen supply device is arranged on the circulating flue and is positioned between the ammonia injection system and the flue gas sealing cover;
the second path of flue gas discharged after being treated by the dedusting and denitration integrated device is divided into two paths of return flue gas and circulating flue gas;
the return flue gas is led back into the built-in combustion furnace through a combustion-supporting flue and is used for supporting combustion of coal gas;
the circulating flue gas enters the circulating flue, the circulating flue gas sequentially passes through the ammonia injection system and the oxygen supply device and then enters the flue gas sealing cover through a plurality of branches, and the circulating flue gas in the flue gas sealing cover is subjected to denitration treatment for the fourth time in a material layer of the sintering machine, namely, the re-sintering process of the circulating flue gas in the sintering machine is completed.
5. The integrated treatment device for the sintering flue gas circulation combined total pollutants as claimed in claim 1, wherein the discharged flue gas purification system further comprises a sintering main exhaust fan and a chimney;
the desulfurization and dust removal integrated device comprises a desulfurization device and a dust removal device, wherein the mixed flue gas enters the desulfurization device for primary desulfurization treatment, and the mixed flue gas after the primary desulfurization enters the dust removal device for dust removal treatment and secondary desulfurization treatment;
the mixed flue gas is discharged after being treated by the dust removal device and enters the external exhaust flue, and the mixed flue gas enters the chimney through the action of the sintering main exhaust fan and then is discharged.
6. The integrated treatment device for the sintering flue gas circulation combined total pollutants as claimed in claim 5, wherein the desulfurization device comprises a desulfurization coil pipe, a first desulfurizer injection port and a second desulfurizer injection port which are vertically arranged;
the desulfurization coiled pipe at least comprises a lower portion bend and an upper portion bend, one end of the desulfurization coiled pipe is provided with a desulfurization flue gas inlet, the other end of the desulfurization coiled pipe is provided with a desulfurization flue gas outlet, the mixed flue gas enters the desulfurization coiled pipe through the desulfurization flue gas inlet, the first desulfurizer spraying inlet is formed in the desulfurization flue gas inlet, the second desulfurizer spraying inlet is formed in the lower portion bend, and the desulfurization flue gas outlet is communicated with the dust removal device; the first desulfurizer spraying port is used for spraying unreacted desulfurization ash, and the second desulfurizer spraying port is used for spraying fresh desulfurizer;
and the desulfurization ash and the fresh desulfurizer are sprayed into the desulfurization coiled pipe to perform the first desulfurization treatment, and the mixed flue gas after the first desulfurization enters the dust removal device.
7. The sintering flue gas circulation combined whole pollutant integrated treatment device according to claim 4, wherein the sintering flue gas circulation system further comprises a combustion fan, a circulation fan, a regulating valve, a first CEMS analyzer, a second CEMS analyzer, a third CEMS analyzer, a pressure detection device and an oxygen concentration analyzer;
the combustion-supporting fan is arranged between the dust removal and denitration integrated device and the built-in combustion furnace, is arranged on the combustion-supporting flue and is used for introducing the return flue gas;
the circulating fan is arranged between the dedusting and denitration integrated device and the ammonia injection system, is arranged on the circulating flue and is used for accelerating the flow of the circulating flue gas;
the regulating valve is arranged on the branch and used for regulating the gas pressure of the flue gas in the flue gas sealing cover;
the first CEMS analyzer is arranged on the middle front section flue and is positioned between the gas-gas heat exchanger and the first ammonia injection grid, the second CEMS analyzer is arranged in the dust removal and denitration integrated device and is positioned between the back blowing device and the second ammonia injection grid, and the third CEMS analyzer is arranged on the middle front section flue and is positioned at an outlet of the dust removal and denitration integrated device;
the first CEMS analyzer, the second CEMS analyzer and the third CEMS analyzer are used for detecting a first flue gas parameter of the second flue gas and adjusting the injection amount of the ammonia source in the first ammonia injection grid and the second ammonia injection grid according to the first flue gas parameter;
the pressure detection device is arranged on the smoke sealing cover and is used for detecting the air pressure of smoke in the smoke sealing cover;
the oxygen concentration analyzer is arranged on the smoke sealing cover and used for analyzing oxygen data in the smoke sealing cover.
8. The integrated treatment device for the sintering flue gas circulation combined total pollutants as claimed in claim 7, wherein the oxygen supply device comprises an oxygen buffer tank and an oxygen uniform distributor;
the oxygen buffer tank is provided with an oxygen inlet and an oxygen outlet, the input end of the oxygen distributor is connected with the oxygen outlet, and the output end of the oxygen distributor is arranged on the circulating flue;
the oxygen supply device adjusts the spraying amount of oxygen according to the data of the oxygen concentration analyzer.
9. The integrated treatment device for the sintering flue gas circulation combined total pollutants as claimed in claim 6, wherein the discharged flue gas purification system further comprises a fourth CEMS analyzer, a fifth CEMS analyzer and a sixth CEMS analyzer;
the fourth CEMS analyzer is arranged on the mixing flue and is positioned at the upstream of the first desulfurizer spraying opening, the fifth CEMS analyzer is arranged on the mixing flue and is positioned between the first desulfurizer spraying opening and the second desulfurizer spraying opening, and the sixth CEMS analyzer is arranged on the external discharge flue and is positioned between the sintering main exhaust fan and the chimney;
and the fourth CEMS analyzer, the fifth CEMS analyzer and the sixth CEMS analyzer are used for detecting a second flue gas parameter of the mixed flue gas and adjusting the spraying amount of the desulfurized ash and the fresh desulfurizer according to the second flue gas parameter.
10. The integrated treatment device for the sintering flue gas circulation combined total pollutants according to claim 2, wherein the integrated device for desulfurization and dust removal is an organic combination of a dry or semi-dry desulfurization device and a bag-type dust remover;
preferably, the back blowing device is a pulse back blowing device;
the SCR denitration catalyst layer is in a plate type, a honeycomb type or a corrugated plate type;
preferably, the SCR denitration catalyst layer is in a honeycomb form.
CN202011380986.1A 2020-11-30 2020-11-30 Sintering flue gas circulation combined full-pollutant integrated treatment device Pending CN112316587A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117563402A (en) * 2023-11-17 2024-02-20 国能长源荆门发电有限公司 Flue gas treatment method, device, equipment and medium based on thermal power plant

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117563402A (en) * 2023-11-17 2024-02-20 国能长源荆门发电有限公司 Flue gas treatment method, device, equipment and medium based on thermal power plant
CN117563402B (en) * 2023-11-17 2024-04-26 国能长源荆门发电有限公司 Flue gas treatment method, device, equipment and medium based on thermal power plant

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