CN111043620A - System and method for realizing SCR full-time denitrification for coal-fired thermal power units - Google Patents
System and method for realizing SCR full-time denitrification for coal-fired thermal power units Download PDFInfo
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- CN111043620A CN111043620A CN201911137307.5A CN201911137307A CN111043620A CN 111043620 A CN111043620 A CN 111043620A CN 201911137307 A CN201911137307 A CN 201911137307A CN 111043620 A CN111043620 A CN 111043620A
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- combustion chamber
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- temperature
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- 238000000034 method Methods 0.000 title claims abstract description 11
- 239000003546 flue gas Substances 0.000 claims abstract description 54
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 53
- 239000000446 fuel Substances 0.000 claims abstract description 5
- 239000000843 powder Substances 0.000 claims abstract description 5
- 238000002485 combustion reaction Methods 0.000 claims description 99
- 239000000779 smoke Substances 0.000 claims description 10
- 238000001816 cooling Methods 0.000 claims description 8
- 230000009471 action Effects 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 230000008569 process Effects 0.000 claims description 3
- 239000007789 gas Substances 0.000 abstract description 5
- 230000007613 environmental effect Effects 0.000 abstract description 3
- 239000007788 liquid Substances 0.000 abstract 1
- 239000003245 coal Substances 0.000 description 7
- 239000003054 catalyst Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 238000010977 unit operation Methods 0.000 description 2
- 241000251468 Actinopterygii Species 0.000 description 1
- 239000002283 diesel fuel Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J15/00—Arrangements of devices for treating smoke or fumes
- F23J15/08—Arrangements of devices for treating smoke or fumes of heaters
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J2900/00—Special arrangements for conducting or purifying combustion fumes; Treatment of fumes or ashes
- F23J2900/15081—Reheating of flue gases
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
Abstract
The invention discloses a system and a method for realizing SCR full-time denitration by a coal-fired thermal power generating unit, and belongs to the technical field of flue gas denitration of coal-fired thermal power plants. The invention aims to solve the following problems: when a coal-fired power plant unit is started to carry out powder feeding, low-load peak regulation operation (the load rate is less than or equal to 40 percent generally) and the unit is stopped, the flue gas temperature at the inlet of a denitration System (SCR) is lower than denitration operation temperature, and the denitration system can not be put into operation to remove NOx, namely, the problem of denitration of the unit in the whole period can not be met. The invention adopts the burner and the matching system thereof, heats part of flue gas in the flue by burning external fuel (gas or liquid and the like), and then mixes the heated high-temperature flue gas with the cold flue gas in the original flue, so that the temperature of the flue gas at the denitration inlet is higher than the denitration commissioning requirement temperature in each stage of starting, low-load running and shutdown of the unit, and the full-time denitration requirement of the unit is met, thereby meeting the requirement of the unit on full-time environmental protection (NOx) emission.
Description
Technical Field
The invention relates to a system and a method for realizing SCR full-time denitration by a coal-fired thermal power generating unit, belonging to the technical field of flue gas denitration of coal-fired thermal power plants.
Background
In order to meet the requirement of NOx emission concentration of the thermal power generating unit, the thermal power generating unit is provided with an SCR denitration device. The normal working temperature range of the catalyst of the denitration device is 300-420 ℃, and the catalyst cannot play the due role when the temperature exceeds the temperature range. When the unit participates in deep peak regulation (low-load operation), the inlet smoke temperature of the denitration system of the unit is usually lower than 300 ℃, so that the normal operation requirement of the denitration system cannot be met, and the environmental protection index cannot reach the standard.
The boiler requires that the mean value of the pollutant emission hour data (converted) concentration is not overproof during low-load operation, and the emission of the boiler reaches the standard during starting, stopping and operation of each load. And during the starting and stopping processes of the coal-fired unit, the flue gas temperature at the SCR inlet is lower during the operation with lower load, and the denitration operation requirement can not be met.
From the current denitration technology condition of the unit under the wide load operation, the denitration technology under the wide load is limited by the temperature rise amplitude, only the problem of the unit under the low load denitration operation can be solved, but the denitration operation starting and stopping requirements can not be met, and based on the reasons, the full-time denitration technology which simultaneously meets the denitration operation conditions under the low load and the start and stop of the SCR is urgently developed.
Disclosure of Invention
The invention aims to solve the problems that the inlet flue gas temperature of a denitration System (SCR) can not meet the denitration commissioning requirement and the full-time denitration of a unit can not be met in the whole processes of start-up powder feeding, low-load peak shaving operation (the general load rate is less than or equal to 40%) and unit shutdown of a coal-fired power plant unit, and further provides a system and a method for realizing SCR full-time denitration by the coal-fired power plant unit.
The technical scheme adopted by the invention for solving the problems is as follows: a system for realizing SCR full-time denitration by a coal-fired thermal power generating unit comprises a boiler original flue, wherein the boiler original flue comprises a unit coal economizer outlet flue and a downstream flue, the unit coal economizer outlet flue is communicated with the downstream flue, and the downstream flue is communicated to a denitration system; the boiler is characterized in that a plurality of bypass pipelines are arranged on the outer side of the unit economizer outlet flue, one end of each bypass pipeline is communicated with the unit economizer outlet flue, a bypass pipeline gate valve is installed at one end of each bypass pipeline, a burner is arranged at the other end of the unit economizer outlet flue, the burner is communicated with an inlet of the combustion chamber, the other end of the unit economizer outlet flue is communicated to an inlet of the combustion chamber, a bypass booster fan is installed in the middle of each bypass pipeline, an outlet of the combustion chamber is communicated with a mixing main pipe, a plurality of mixing inlet flue branch pipes are arranged on the mixing main pipe, and the mixing inlet flue branch pipes are communicated with the unit economizer outlet flue.
Further, the combustion chamber comprises combustion chamber overcoat and interior combustion chamber, interior combustion chamber is located the inside of combustion chamber overcoat, and has the clearance between interior combustion chamber and the combustion chamber overcoat, the several cooling hole has been seted up on the interior combustion chamber, the entry intercommunication of combustor and interior combustion chamber, the export of interior combustion chamber communicates to the inside of combustion chamber overcoat, the entry intercommunication of bypass pipeline and combustion chamber overcoat, the export and the mixed mother pipe intercommunication of combustion chamber overcoat.
Furthermore, the bypass pipelines are symmetrically arranged on two sides of the outlet flue of the unit economizer, and each bypass pipeline is provided with a bypass pipeline gate valve and a bypass booster fan.
Furthermore, the number of the burners is determined by the unit operation flue gas parameters, and the number of the combustion chambers, the bypass pipelines, the bypass pipeline gate valves thereon and the bypass booster fans are all matched with the number of the burners.
Furthermore, the bypass pipeline is communicated to the upper part of an outlet flue of the unit coal economizer, the mixed flue-in branch pipe is communicated to the lower part of the outlet flue of the unit coal economizer, and the number of the mixed flue-in branch pipes is determined by the uniformity of a temperature field at an inlet of the denitration system after the high-temperature flue gas and the original flue gas of the boiler are mixed.
The working method of the system for realizing SCR full-time denitration by the coal-fired thermal power generating unit is characterized by comprising the following steps of: in the starting stage of the unit, when the boiler starts to throw powder, the system is put into operation; the original flue gas of the boiler enters the combustion chamber through a bypass pipeline under the action of a bypass supercharging fan, one part of the flue gas entering the combustion chamber enters the inner combustion chamber through a cooling hole to be mixed with high-temperature flue gas generated by combustion fuel of the combustor, the other part of the flue gas entering the combustion chamber flows through a gap between an outer sleeve of the combustion chamber and the inner combustion chamber, and the two parts of the flue gas cool the inner combustion chamber so as to ensure the safety of the inner combustion chamber; the flue gas outside the inner combustion chamber is mixed with the high-temperature flue gas in the inner combustion chamber at the outlet of the inner combustion chamber, so that the temperature of the high-temperature flue gas discharged from the inner combustion chamber after mixing is reduced to be within the material safety temperature of the mixing main pipe, then the flue gas enters the mixing main pipe, the flue gas discharged from different combustion chambers is mixed to the mixing main pipe, then the mixed flue gas is mixed into the original flue of the boiler through the mixing inlet flue branch pipe and is mixed with the cold flue gas in the original flue of the boiler, and the temperature of the mixed SCR inlet flue gas meets the denitration delivery temperature requirement; along with the unit starts, the smoke temperature in the original flue of the boiler is gradually increased, the operation power and the number of the burners are correspondingly reduced, and the system is completely withdrawn until the smoke temperature at the SCR inlet of the boiler can meet the denitration operation requirement. The operation mode of the system is similar for other load sections of the unit.
Compared with the prior art, the invention has the following advantages and effects: the system adopts the combustor and a supporting system thereof, heats partial flue gas by burning external fuel (light diesel oil or natural gas and the like), mixes the heated high-temperature flue gas with cold flue gas in an original flue, enables the unit to run at low load and stop running at each stage, ensures that the flue gas temperature at a denitration inlet is higher than the denitration commissioning requirement temperature, meets the denitration requirement of the unit at the whole time, and further meets the requirement of the unit on the emission of environmental protection (NOx) at the whole time.
Drawings
Fig. 1 is a schematic view of the overall structure of the embodiment of the present invention.
FIG. 2 is a schematic view of a combustion chamber according to an embodiment of the present invention.
FIG. 3 is a comparison of the SCR inlet smoke temperature change curve during the boiler start-up phase when the system is used for heating and the SCR inlet smoke temperature change curve during the original oil feeding start-up.
In the figure: the unit coal economizer comprises an outlet flue 1, a downstream flue 2, a combustor 3, a combustion chamber 4, a bypass pipeline gate valve 5, a bypass pipeline 6, a bypass booster fan 7, a mixing main pipe 8, a mixing inlet flue branch pipe 9, a combustion chamber jacket 10, an inner combustion chamber 11 and a cooling hole 12.
Detailed Description
The present invention will be described in further detail below by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not to be construed as limiting the present invention.
Referring to fig. 1 to 2, the system for realizing SCR full-time denitration by a coal-fired thermal power generating unit in the embodiment includes an original boiler flue, the original boiler flue includes a unit economizer outlet flue 1 and a downstream flue 2, the unit economizer outlet flue 1 is communicated with the downstream flue 2, and the downstream flue 2 is communicated to a denitration system; the outside of unit economizer export flue 1 is provided with a plurality of bypass pipeline 6, the one end and the unit economizer export flue 1 intercommunication of bypass pipeline 6, and bypass pipeline gate valve 5 is installed to the one end of bypass pipeline 6, the other end of unit economizer export flue 1 is provided with combustor 3, combustor 3 and combustion chamber 4's entry intercommunication, the other end of unit economizer export flue 1 communicates to the entrance of combustion chamber 4, bypass booster fan 7 is installed at the mid-mounting of bypass pipeline 6, the export and the mixed mother pipe 8 intercommunication of combustion chamber 4, be provided with many on the mixed mother pipe 8 and mix into flue branch pipe 9, it communicates with unit economizer export flue 1 to mix into flue branch pipe 9.
The combustion chamber 4 comprises combustion chamber overcoat 10 and interior combustion chamber 11, interior combustion chamber 11 is located the inside of combustion chamber overcoat 10, and have the clearance between interior combustion chamber 11 and the combustion chamber overcoat 10, set up the cooling hole 12 of several fish scale form on the interior combustion chamber 11, combustor 3 communicates with the entry of interior combustion chamber 11, the export of interior combustion chamber 11 communicates to the inside of combustion chamber overcoat 10, bypass pipeline 6 communicates with the entry of combustion chamber overcoat 10, the export and the mixed mother pipe 8 intercommunication of combustion chamber overcoat 10.
The bypass pipelines 6 are symmetrically arranged on two sides of the outlet flue 1 of the unit economizer, and each bypass pipeline 6 is provided with a set of bypass pipeline gate valve 5 and a bypass booster fan 7.
The number of the combustion engines 3 is determined by the unit operation smoke parameters, and the number of the combustion chambers 4, the bypass pipelines 6, the bypass pipeline gate valves 5 on the bypass pipelines and the bypass booster fans 7 is matched with the number of the combustion engines 3.
The bypass pipeline 6 is communicated to the upper part of the outlet flue 1 of the unit coal economizer, the mixed-in flue branch pipe 9 is communicated to the lower part of the outlet flue 1 of the unit coal economizer, and the number of the mixed-in flue branch pipes 9 is determined by the uniformity of the inlet temperature field of the denitration system after the high-temperature flue gas and the original flue gas of the boiler are mixed.
The working method comprises the following steps: in the starting stage of the unit, when the boiler starts to throw powder, the system is put into operation; the original flue gas of the boiler enters the combustion chamber 4 through the bypass pipeline 6 under the action of the bypass booster fan 7, one part of the gas entering the combustion chamber 4 enters the inner combustion chamber 11 through the cooling hole 12 to be mixed with high-temperature gas generated by burning fuel by the burner 3, the other part of the gas entering the combustion chamber 4 flows through a gap between the combustion chamber jacket 10 and the inner combustion chamber 11, and the two parts of the gas play a role of cooling the inner combustion chamber 11 so as to ensure the safety of the inner combustion chamber 11; the flue gas outside the inner combustion chamber 11 is mixed with the high-temperature flue gas in the inner combustion chamber 11 at the outlet of the inner combustion chamber 11, so that the temperature of the high-temperature flue gas discharged from the mixed inner combustion chamber 11 is reduced to be within the material safety temperature of the mixing main pipe 8, then the flue gas enters the mixing main pipe 8, the flue gas discharged from different combustion chambers 4 is mixed to the mixing main pipe 8, then the mixed flue gas is mixed into the original flue of the boiler through the mixing inlet flue branch pipe 9 and is mixed with the cold flue gas in the original flue of the boiler, and the temperature of the mixed SCR inlet flue gas meets the denitration delivery temperature requirement; along with the unit starts, the smoke temperature in the original flue of the boiler is gradually increased, the operation power and the number of the burners 3 are correspondingly reduced, and the system is completely withdrawn until the smoke temperature at the SCR inlet of the boiler can meet the denitration operation requirement. The operation mode of the system is similar for other load sections of the unit.
Those not described in detail in this specification are well within the skill of the art.
Although the present invention has been described with reference to the above embodiments, it should be understood that the scope of the present invention is not limited thereto, and that various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the present invention.
Claims (6)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911137307.5A CN111043620A (en) | 2019-11-19 | 2019-11-19 | System and method for realizing SCR full-time denitrification for coal-fired thermal power units |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911137307.5A CN111043620A (en) | 2019-11-19 | 2019-11-19 | System and method for realizing SCR full-time denitrification for coal-fired thermal power units |
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| CN111043620A true CN111043620A (en) | 2020-04-21 |
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| CN201911137307.5A Pending CN111043620A (en) | 2019-11-19 | 2019-11-19 | System and method for realizing SCR full-time denitrification for coal-fired thermal power units |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201196415Y (en) * | 2008-04-24 | 2009-02-18 | 石家庄得宝机械制造有限公司 | Novel high-speed combustor |
| US20120160142A1 (en) * | 2011-03-04 | 2012-06-28 | Foster Wheeler North America Corp. | Method of and Apparatus for Selective Catalytic NOx Reduction in a Power Boiler |
| CN203010582U (en) * | 2012-12-03 | 2013-06-19 | 南京博纳能源环保科技有限公司 | Waste heat dynamic afterburning incinerator |
| CN204962817U (en) * | 2015-09-08 | 2016-01-13 | 东方电气集团东方锅炉股份有限公司 | SCR flue gas denitration system that full load mode put into operation |
| CN205448291U (en) * | 2016-03-24 | 2016-08-10 | 黄石市天达热能设备有限公司 | A energy -saving hot -blast furnace for flue gas is handled |
| CN109589788A (en) * | 2018-12-05 | 2019-04-09 | 武汉奥杰科技股份有限公司 | A kind of Novel flue gas denitrating system |
| CN110201532A (en) * | 2019-03-27 | 2019-09-06 | 宁波大学 | A kind of full load denitrating system improving SCR inlet smoke temperature using gas fuel burning |
| CN209530550U (en) * | 2019-01-28 | 2019-10-25 | 九源天能（北京）科技有限公司 | A kind of energy-saving SCR denitration device |
| CN211925807U (en) * | 2019-11-19 | 2020-11-13 | 华电电力科学研究院有限公司 | System for realizing SCR full-time denitration of coal-fired thermal power generating unit |
-
2019
- 2019-11-19 CN CN201911137307.5A patent/CN111043620A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201196415Y (en) * | 2008-04-24 | 2009-02-18 | 石家庄得宝机械制造有限公司 | Novel high-speed combustor |
| US20120160142A1 (en) * | 2011-03-04 | 2012-06-28 | Foster Wheeler North America Corp. | Method of and Apparatus for Selective Catalytic NOx Reduction in a Power Boiler |
| CN203010582U (en) * | 2012-12-03 | 2013-06-19 | 南京博纳能源环保科技有限公司 | Waste heat dynamic afterburning incinerator |
| CN204962817U (en) * | 2015-09-08 | 2016-01-13 | 东方电气集团东方锅炉股份有限公司 | SCR flue gas denitration system that full load mode put into operation |
| CN205448291U (en) * | 2016-03-24 | 2016-08-10 | 黄石市天达热能设备有限公司 | A energy -saving hot -blast furnace for flue gas is handled |
| CN109589788A (en) * | 2018-12-05 | 2019-04-09 | 武汉奥杰科技股份有限公司 | A kind of Novel flue gas denitrating system |
| CN209530550U (en) * | 2019-01-28 | 2019-10-25 | 九源天能（北京）科技有限公司 | A kind of energy-saving SCR denitration device |
| CN110201532A (en) * | 2019-03-27 | 2019-09-06 | 宁波大学 | A kind of full load denitrating system improving SCR inlet smoke temperature using gas fuel burning |
| CN211925807U (en) * | 2019-11-19 | 2020-11-13 | 华电电力科学研究院有限公司 | System for realizing SCR full-time denitration of coal-fired thermal power generating unit |
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Application publication date: 20200421 |