CN113813755A - Denitration full-load commissioning control method for coal-fired unit - Google Patents
Denitration full-load commissioning control method for coal-fired unit Download PDFInfo
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- CN113813755A CN113813755A CN202110979512.7A CN202110979512A CN113813755A CN 113813755 A CN113813755 A CN 113813755A CN 202110979512 A CN202110979512 A CN 202110979512A CN 113813755 A CN113813755 A CN 113813755A
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- 238000000034 method Methods 0.000 title claims abstract description 47
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 105
- 239000003546 flue gas Substances 0.000 claims abstract description 105
- 239000007789 gas Substances 0.000 claims abstract description 66
- 239000000779 smoke Substances 0.000 claims abstract description 37
- 230000003197 catalytic effect Effects 0.000 claims abstract description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 33
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- 239000001301 oxygen Substances 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims 1
- 239000002994 raw material Substances 0.000 claims 1
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 abstract description 33
- 239000003054 catalyst Substances 0.000 abstract description 29
- 230000009466 transformation Effects 0.000 abstract description 7
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 6
- 238000005192 partition Methods 0.000 description 6
- 238000012546 transfer Methods 0.000 description 5
- 230000008901 benefit Effects 0.000 description 4
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- 238000006243 chemical reaction Methods 0.000 description 4
- 238000013461 design Methods 0.000 description 4
- 239000000446 fuel Substances 0.000 description 4
- AKEJUJNQAAGONA-UHFFFAOYSA-N sulfur trioxide Chemical compound O=S(=O)=O AKEJUJNQAAGONA-UHFFFAOYSA-N 0.000 description 4
- 230000007613 environmental effect Effects 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 239000003245 coal Substances 0.000 description 2
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- 230000009471 action Effects 0.000 description 1
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- 238000003915 air pollution Methods 0.000 description 1
- BIGPRXCJEDHCLP-UHFFFAOYSA-N ammonium bisulfate Chemical compound [NH4+].OS([O-])(=O)=O BIGPRXCJEDHCLP-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
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- 238000002360 preparation method Methods 0.000 description 1
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- 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
- B01D53/74—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
Abstract
The invention discloses a coal-fired unit denitration full-load commissioning control method, which comprises the steps of detecting the gas temperature at an inlet of a denitration device through a temperature detector, and inputting the detected gas temperature into a controller through the temperature detector; a temperature threshold value is preset in the controller, the gas temperature is compared with the temperature threshold value, and the controller sends an instruction to the smoke regulation controller; the flue gas adjusting controller controls the amount of gas of high-temperature flue gas in the side flue of the reheater entering the inlet of the denitration device according to instructions, so that the amount of flue gas of the high-temperature flue gas in the side flue of the reheater entering the inlet of the denitration device is increased, the inlet temperature of the denitration device can reach the lowest continuous catalytic temperature of the denitration catalyst, a flue gas denitration system runs at full load, nitrogen oxides in the flue gas are removed, the environment-friendly emission requirement is met, meanwhile, technical transformation is not needed, the transformation investment cost is greatly saved, the original structure of equipment is not changed, and the influence on the operation condition of a boiler and the equipment is avoided.
Description
Technical Field
The invention relates to the technical field of denitration of coal-fired units, in particular to a denitration full-load commissioning control method for a coal-fired unit.
Background
With the stricter and stricter management and control of national environmental protection indexes, various indexes in flue gas emission must meet national standards, wherein the nitrogen oxide control technology can be divided into a Selective Catalytic Reduction (SCR) technology and a non-selective catalytic reduction (SNCR) technology, ammonia mixed with air is sprayed into flue gas by a denitration system of the Selective Catalytic Reduction (SCR) technology, and nitrogen oxide in the flue gas reacts with the ammonia to be reduced into nitrogen and water under the action of a catalyst, so that the aim of purifying the nitrogen oxide is fulfilled. The SCR denitration system mainly comprises a liquid ammonia storage system, an ammonia gas preparation system and a reaction system. The reaction system adopts honeycomb type, plate type and corrugated plate type catalysts, the core of the SCR denitration system is the catalyst, and the catalyst has strict requirements on the temperature of the operating flue gas.
Present thermal power factory all installs flue gas denitration system, for the stability of guaranteeing the electricity generation with improve the generating efficiency, needs the full load operation of SCR denitration, will realize the full load operation of SCR denitration, and the technical route has 2: 1. the method has the advantages that the smoke temperature is adaptive to a denitration system, a boiler thermodynamic system or a smoke system is required to be modified, the smoke temperature is controlled, the defects are that the modification work is complicated, a large amount of time, energy and cost are required to be consumed, due to site limitation, modification is often difficult, denitration of a coal-fired unit cannot be carried out at full load, denitration is not thorough, and long-time nitrogen oxide (NOx) emission of the coal-fired unit after grid connection exceeds the standard, so that air pollution is caused; 2. the catalyst adapts to the smoke temperature, the low-temperature catalyst is adopted to simultaneously remove the sulfur trioxide in the smoke, and the low-temperature catalyst and the sulfur trioxide removal technology are expensive at present, so that the enterprise is not facilitated to reduce the power generation cost.
Disclosure of Invention
This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.
Therefore, the technical problems to be solved by the invention are as follows: the method is characterized in that the work of modifying a boiler thermodynamic system or a flue gas system is complicated, a large amount of time, energy and cost are consumed, modification is difficult due to site limitation, and therefore denitration of a coal-fired unit cannot be carried out at full load and is not thorough, and NOx emission of the coal-fired unit exceeds the standard for a long time after grid connection, so that atmospheric pollution is caused.
In order to solve the technical problems, the invention provides the following technical scheme: the denitration full-load operation control method for the coal-fired unit comprises the steps of detecting the gas temperature at an inlet of a denitration device through a temperature detector, and inputting the detected gas temperature into a controller through the temperature detector; a temperature threshold value is preset in the controller, the gas temperature is compared with the temperature threshold value, and the controller sends an instruction to the smoke regulation controller; and the flue gas adjusting controller adjusts the opening angle of a reheater side flue baffle in the double flues at the tail part of the boiler according to the instruction, and adjusts the amount of gas of high-temperature gas in the reheater side flue entering the inlet of the denitration device.
As a preferred scheme of the denitration full-load operation control method for the coal-fired unit, the denitration full-load operation control method comprises the following steps: a first temperature threshold and a second temperature threshold are arranged in the controller, and the second temperature threshold is higher than the first temperature threshold; the controller compares the gas temperature detected by the temperature detector with a first temperature threshold value, wherein the gas temperature is less than the first temperature threshold value; the controller sends a first instruction to the smoke adjusting baffle; the flue gas regulation controller receives a first instruction and controls a reheater side flue baffle to increase an opening angle; the amount of high temperature flue gas entering the inlet of the denitrification device is increased, and the temperature of the denitrification device is increased to reach the catalytic temperature.
As a preferred scheme of the denitration full-load operation control method for the coal-fired unit, the denitration full-load operation control method comprises the following steps: the controller compares the gas temperature detected by the temperature detector with a first temperature threshold value, and the gas temperature is greater than the first temperature threshold value; the controller compares the gas temperature detected by the temperature detector with a second temperature threshold value, and the gas temperature is greater than the second temperature threshold value; the controller sends a second instruction to the smoke adjusting baffle; the smoke regulation controller receives a second instruction and controls the flue plate at the side of the reheater to reduce the opening angle; the high-temperature flue gas volume that gets into the denitrification facility entry reduces, and denitrification facility temperature reduces relatively.
As a preferred scheme of the denitration full-load operation control method for the coal-fired unit, the denitration full-load operation control method comprises the following steps: after receiving the first instruction, the smoke regulation controller sends a third instruction to the regulation valve; the regulating valve receives a third instruction to open and opens the auxiliary steam main pipe; the steam in the auxiliary steam main pipe enters a deaerator to heat water in the deaerator; after the deaerator removes oxygen in water, the water heated in the deaerator conveys the water into the high-pressure heater through the water pump; the high-pressure heater is internally pumped into the economizer after being secondarily heated by high-pressure steam extraction, so that the temperature of water supply in the economizer is increased.
As a preferred scheme of the denitration full-load operation control method for the coal-fired unit, the denitration full-load operation control method comprises the following steps: after receiving the second instruction, the smoke regulation controller sends a fourth instruction to the regulation valve; and the regulating valve receives a fourth instruction to close and seals the auxiliary steam main pipe.
As a preferred scheme of the denitration full-load operation control method for the coal-fired unit, the denitration full-load operation control method comprises the following steps: the temperature detector continuously detects the gas temperature at the inlet of the denitration device, and the detection intervals are the same time period every time.
As a preferred scheme of the denitration full-load operation control method for the coal-fired unit, the denitration full-load operation control method comprises the following steps: an interval threshold value is also arranged in the controller; the controller compares the gas temperature detected by the temperature detector with a first temperature threshold value, and the gas temperature is greater than the first temperature threshold value; the controller compares the gas temperature detected by the temperature detector with a second temperature threshold value, wherein the gas temperature is less than the second temperature threshold value; and the controller subtracts the gas temperature detected by the temperature detector from the gas temperature detected last time, and calculates to obtain the temperature difference.
As a preferred scheme of the denitration full-load operation control method for the coal-fired unit, the denitration full-load operation control method comprises the following steps: the temperature difference is a positive value; the controller accesses the interval threshold; the controller compares the temperature difference with an interval threshold value, and the absolute value of the temperature difference is greater than the absolute value of the interval threshold value; the controller sends a fifth instruction to the smoke adjusting baffle; the flue gas regulation controller receives a fifth instruction, and reduces the opening angle of a reheater side flue baffle; the controller accesses the interval threshold; comparing the temperature difference with an interval threshold, wherein the absolute value of the temperature difference is smaller than the absolute value of the interval threshold; the controller regulates a sixth instruction of the baffle plate for the flue gas; and the smoke regulation controller receives and sends a sixth instruction to reduce the opening angle of the reheater side flue damper.
As a preferred scheme of the denitration full-load operation control method for the coal-fired unit, the denitration full-load operation control method comprises the following steps: the temperature difference is a negative value; the controller accesses the interval threshold; the controller compares the temperature difference with an interval threshold value, and the absolute value of the temperature difference is greater than the absolute value of the interval threshold value; the controller sends a seventh instruction to the smoke adjusting baffle; the flue gas regulation controller receives a seventh instruction and increases the opening angle of a reheater side flue baffle; the controller accesses the interval threshold; the controller compares the temperature difference with an interval threshold value, and the absolute value of the temperature difference is smaller than the absolute value of the interval threshold value; the controller sends an eighth instruction to the smoke adjusting baffle; and the flue gas regulation controller receives an eighth instruction and increases the opening angle of the reheater side flue damper.
As a preferred scheme of the denitration full-load operation control method for the coal-fired unit, the denitration full-load operation control method comprises the following steps: the flue gas adjusting controller receives a sixth instruction and an eighth instruction, and the adjusting angle of the reheater side flue damper is smaller than the adjusting angle when the fifth instruction and the seventh instruction are received; and the adjustment angle of the smoke adjustment controller receiving the fifth instruction, the sixth instruction, the seventh instruction and the eighth instruction is far smaller than the adjustment angle of the smoke adjustment controller receiving the first instruction and the second instruction.
The invention has the beneficial effects that: according to the invention, the opening angle of the baffle plate of the reheater side flue in the double flues at the tail part of the boiler is adjusted, so that the gas quantity of high-temperature flue gas in the reheater side flue entering the inlet of the denitration device is controlled, the gas quantity of the high-temperature flue gas in the reheater side flue entering the inlet of the denitration device is increased, the inlet temperature of the denitration device can reach the lowest continuous catalytic temperature of a denitration catalyst, a flue gas denitration system runs at full load, nitrogen oxides in the flue gas are removed, the environmental-friendly emission requirement is met, meanwhile, technical transformation is not needed, the transformation investment cost is greatly saved, the original structure of equipment is not changed, and the operation condition of the boiler and the equipment is not influenced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise. Wherein:
fig. 1 is a flow chart of the first embodiment.
Fig. 2 is a control flow chart of the controller when the detected gas temperature is less than the first temperature threshold and greater than the second temperature threshold in the second embodiment.
FIG. 3 is a schematic view of the structure of a flue of a boiler in the second and third embodiments.
Fig. 4 is a diagram showing the overall arrangement of a boiler and a flow of steam and water in a second embodiment.
Fig. 5 is a graph showing the change in the temperature of the boiler feed water in the third embodiment.
FIG. 6 is a graph showing the inlet temperature change of the denitration device in the third embodiment.
Fig. 7 is a control flowchart of the controller when the detected temperature is greater than the first temperature threshold and less than the second temperature threshold in the second embodiment.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.
Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.
Example 1
Referring to fig. 1, for a first embodiment of the present invention, a denitration full-load commissioning control method for a coal-fired unit is provided, in which a temperature detector detects a gas temperature at an inlet of a denitration device, the temperature detector inputs the detected gas temperature into a controller, and the controller may be an existing mitsubishi PLC programmable controller FX3U series product;
a temperature threshold is preset in the controller, the core of the SCR denitration system is a catalyst, the catalyst has strict requirements on the temperature of the operating flue gas, the temperature interval of continuous catalytic reaction generated by the catalyst can be set as the temperature threshold, the controller compares the gas temperature detected by the temperature detector with the temperature threshold, and the controller sends an instruction to the flue gas regulation controller;
The method comprises the following steps that a smoke regulation controller regulates the opening angle of a reheater side flue baffle in a double flue at the tail part of a boiler according to a command, and regulates the gas quantity of high-temperature gas in the reheater side flue entering an inlet of a denitration device, the smoke regulation controller can adopt a Phoenix AXC1050 type series controller according to the command, the opening angle of the reheater side flue baffle in the double flue at the tail part of the boiler is regulated, the tail flue of the boiler is divided into parallel double flues through a middle partition wall, the double flues are a reheater side flue and an economizer side flue respectively, the reheater side flue baffle is controlled through the opening angle of the reheater side flue baffle, the existing reheater side flue baffle and the economizer side flue baffle are of a linkage structure, and when the opening angle of the reheater side flue baffle is increased, the opening angle of the economizer side flue baffle is correspondingly reduced; when the opening angle of the reheater side flue baffle is reduced, the opening angle of the economizer side flue baffle is correspondingly increased; when the opening angle of the reheater side flue baffle is half of the full opening state, the opening angle of the economizer side flue baffle is also half of the full opening state; when the reheater side flue baffle is completely opened, the economizer side flue baffle is completely closed; and when the reheater side flue baffle is completely closed, the economizer side flue baffle is completely opened.
When reheater side flue baffle opening angle increases, the flue gas volume that high temperature flue gas got into the denitrification facility entry in the reheater side flue increases, can make denitrification facility entry temperature reach the minimum continuous catalysis temperature of denitration catalyst (generally 300 ℃), make flue gas denitration system full load operation, detach the nitrogen oxide in the flue gas, reach the environmental protection emission requirement, need not carry out technical transformation to existing equipment simultaneously, save in a large number and reform transform the investment cost, do not change the original structure of equipment, can not lead to the fact the influence to the boiler, equipment operation operating mode.
Example 2
Referring to fig. 2 to 4 and 7, a second embodiment of the present invention is based on the previous embodiment, a first temperature threshold and a second temperature threshold are provided in the controller, the first temperature threshold is a reaction lowest catalytic temperature of the catalyst (generally 300 ℃), and only if the temperature is higher than the lowest catalytic temperature, the catalyst can continuously and efficiently react, the temperature is too low, the reaction speed is reduced, ammonium bisulfate can be generated to block micropores inside the catalyst, the performance of the catalyst is reduced, the second temperature threshold is a highest bearing temperature of the catalyst, and the flue gas temperature is too high, which can cause burning loss of the catalyst of the denitration device, and affect the strength and performance of the catalyst (generally less than 400 ℃), and the second temperature threshold is higher than the first temperature threshold.
Specifically in this embodiment, the controller compares the gas temperature detected by the temperature detector with a first temperature threshold, the gas temperature being less than the first temperature threshold; the controller sends a first instruction to the smoke adjusting baffle; the flue gas regulation controller receives a first instruction and increases the opening angle of a reheater side flue baffle; the high temperature flue gas volume that gets into the denitrification facility entry increases, the denitrification facility temperature risees and reaches catalytic temperature, the flue gas volume that high temperature flue gas got into the denitrification facility entry in the reheater side flue increases, can make denitrification facility entry temperature reach the minimum continuous catalytic temperature of denitration catalyst, make flue gas denitration system full load operation, detach the nitrogen oxide in the flue gas, reach environmental protection emission requirement, need not carry out technical transformation to current equipment simultaneously, save in a large number and reform transform the investment cost, do not change the original structure of equipment, can not lead to the fact the influence to the boiler, equipment operation operating condition.
Specifically in this embodiment, the controller compares the gas temperature detected by the temperature detector with a first temperature threshold, the gas temperature being greater than the first temperature threshold; then comparing the gas temperature detected by the temperature detector with a second temperature threshold value, wherein the gas temperature is greater than the second temperature threshold value; the controller sends a second instruction to the smoke adjusting baffle; the flue gas regulation controller receives a second instruction and reduces the opening angle of a flue plate at the side of the reheater; the high temperature flue gas volume that gets into the denitrification facility entry reduces, and denitrification facility temperature reduces relatively, prevents that the flue gas temperature is too high, can lead to denitrification facility catalyst scaling loss, influences catalyst strength and performance.
Specifically, in the embodiment, after receiving the first instruction, the flue gas regulation controller sends a third instruction to the regulating valve; the regulating valve receives a third instruction to open and opens the auxiliary steam main pipe; the steam in the auxiliary steam main pipe enters a deaerator to heat water in the deaerator; after the deaerator removes oxygen in water, the water heated in the deaerator conveys the water into the high-pressure heater through the water pump; the invention adopts a matched boiler which is a supercritical unborn sliding pressure operation direct current boiler manufactured by an oriental boiler factory, the boiler model DG3110/26.15-II2, a single hearth, primary middle reheating, balance ventilation and a tail double flue structure, the boiler adopts a built-in starting separation system, adjusts the boiler load by fuel and water supply ratio, adjusts the temperature of main steam by adjusting the fuel and water supply ratio and matching with one-stage and two-stage desuperheating water, adopts a flue gas baffle plate and accident water spray to control the temperature of the reheated steam, the burner is a cyclone burner produced by the technology introduced in the oriental boiler factory, adopts 3 layers of front and rear walls, the front and rear walls are arranged in opposite flushing, the tail of the boiler is of a double flue structure, the middle is provided with a middle flue gas, and the opening degree of a reheater flue gas adjusting baffle plate is controlled, the distribution of the flue gas amount of the front wall and the rear wall of the tail flue is adjusted in the starting process of the unit to adjust the heat exchange amount of the flue gas and the low-pressure, low-pressure and coal economizer, the flue gas adjusting baffle of the reheater is adjusted in the starting process of the unit to ensure that the flue gas basically passes through the low-pressure secondary area tube panel and the heat exchange with the coal economizer is reduced as much as possible, a high-pressure and low-pressure bypass is opened before the boiler is ignited in the starting process of the unit, the low-pressure secondary temperature is gradually increased along with the temperature rise and the pressure rise of the boiler, the heat exchange amount with the flue gas is low, the improvement of the inlet temperature of a denitration device is facilitated, the inlet temperature of the denitration device reaches the minimum continuous catalytic temperature (generally 300 ℃), a flue gas denitration system runs at full load, the nitrogen oxides in the flue gas are removed, the environment-friendly emission requirement is met, the technical transformation of the existing equipment is not needed, the investment cost is greatly saved, and the original structure of the equipment is not changed, the operation conditions of the boiler and the equipment are not affected.
In the embodiment, the fuel is combusted in the hearth to generate high-temperature hot flue gas, a part of heat is transferred to the hearth water-cooled wall and the platen superheater mainly in a radiation heat transfer mode, then the hot flue gas enters a rear shaft wrapping wall through a high-temperature superheater and a high-temperature reheater, a middle partition wall in the rear shaft wrapping wall divides the rear shaft into a front flue and a rear flue which are parallel, a cold section reheater is arranged in the front flue, a low-temperature superheater and an economizer are arranged in the rear flue, the high-temperature flue gas in the heating surface of the flue mainly transfers heat to a medium in a convection heat transfer mode, the temperature of the flue gas is gradually reduced, a flue gas adjusting baffle is arranged behind the low-temperature superheater and the economizer, the device is used for changing the amount of flue gas passing through the front partition wall and the rear partition wall of the vertical shaft to achieve the purpose of adjusting the temperature of reheated steam, the flue gas passing through the flue gas baffle plate enters a denitration system for denitration treatment, and the denitration system reduces NOX in the flue gas by adopting a Selective Catalytic Reduction (SCR) method. The SCR reactor adopts high ash to arrange (that is the reactor is arranged between boiler economizer and air preheater), adopts a stove two reactor structure, and the flue gas flows vertically downwards, and the flue gas gets into the air preheater after the denitration and carries out the final cooling, then gets into two three rooms four electric field electrostatic precipitator purifies the back and discharges to the chimney after the desulfurization through two draught fans and get into the atmosphere.
Specifically in this embodiment, the flue gas regulation controller receives the second command and issues a fourth command to the regulating valve; the regulating valve receives four instructions to close, the main pipe of auxiliary steam is sealed, the original design of the air source for the high pressure air extraction check valve instrument is linked with the steam turbine OPC electromagnetic valve, the OPC electromagnetic valve is 220VDC, the normally closed electromagnetic valve, after the unit is stopped, the OPC electromagnetic valve acts, the OPC oil pressure is not established before the steam turbine is hung, the air source for the high pressure air extraction check valve instrument is lost, the air extraction check valve is closed, the air source for the #2 high pressure air extraction check valve standby instrument is added, after the boiler is ignited during the starting period of the unit, the air source for the #2 high pressure air extraction check valve standby instrument is opened, the air source for the normal instrument is closed, the #2 high pressure instrument is timely put into operation, and the water supply temperature is improved as early as possible. .
In the present embodiment, the temperature detector continuously detects the gas temperature at the inlet of the denitration device, and every detection is separated by the same time period (in the present invention, the detection is set to be once every second).
In the embodiment, an interval threshold is arranged in the controller, and the interval threshold in the controller can be set to be +/-5 ℃; the controller compares the gas temperature detected by the temperature detector with a first temperature threshold, and the gas temperature is greater than the first temperature threshold; the controller compares the gas temperature detected by the temperature detector with a second temperature threshold value, and the gas temperature is less than the second temperature threshold value; that is, the temperature difference is calculated by subtracting the gas temperature detected by the temperature detector and the gas temperature detected in the previous time within the reaction temperature interval (300-400 ℃) of the catalyst.
Specifically in this embodiment, the temperature difference is a positive value; namely, the temperature detected at this time is improved relative to the temperature detected at the last time, and the controller accesses the preset interval threshold; comparing the temperature difference with an interval threshold, wherein the absolute value of the temperature difference is greater than the absolute value of the interval threshold; the improved temperature variation is larger than the interval threshold value (+/-5 ℃), and the controller instructs the smoke adjusting baffle plate to the fifth time; the flue gas regulation controller receives a fifth instruction, and reduces the opening angle of a reheater side flue baffle; the flue gas volume that high temperature flue gas got into the denitrification facility entry in the reheater side flue reduces, can make denitrification facility entry temperature descend.
The controller accesses the interval threshold; comparing the temperature difference with an interval threshold, wherein the absolute value of the temperature difference is smaller than the absolute value of the interval threshold; when the temperature increase amount is detected to be smaller than the interval threshold value (+/-5 ℃), the controller adjusts a sixth instruction of the baffle for the smoke; the flue gas regulation controller receives a sixth instruction, the opening angle of the reheater side flue baffle is increased, the flue gas volume of high-temperature flue gas in the reheater side flue entering the inlet of the denitration device is reduced, and the inlet temperature of the denitration device can be reduced.
Specifically in this embodiment, the temperature difference is a negative value; that is, the temperature detected this time is reduced compared with the temperature detected last time, and the controller accesses the preset interval threshold; comparing the temperature difference with an interval threshold, wherein the absolute value of the temperature difference is greater than the absolute value of the interval threshold; the controller regulates a seventh instruction of the baffle plate for the flue gas; the flue gas adjusting controller receives a seventh instruction, the opening angle of the reheater side flue baffle is increased, the flue gas volume of high-temperature flue gas in the reheater side flue entering the inlet of the denitration device is increased, and the inlet temperature of the denitration device can be increased; the controller accesses a preset interval threshold; the controller compares the temperature difference with an interval threshold value, and the absolute value of the temperature difference is smaller than the absolute value of the interval threshold value; the controller sends an eighth instruction to the smoke adjusting baffle; the flue gas regulation controller receives the eighth instruction, increases the opening angle of the reheater side flue baffle, increases the flue gas volume of high-temperature flue gas in the reheater side flue entering the inlet of the denitration device, and can improve the inlet temperature of the denitration device.
The flue gas adjusting controller receives the sixth instruction and the eighth instruction, and the adjusting angle of the reheater side flue baffle is smaller than the adjusting angle when the fifth instruction and the seventh instruction are received; and the flue gas adjusting controller receives the adjusting angle of the fifth instruction, the sixth instruction, the seventh instruction and the eighth instruction, which is far smaller than the adjusting angle of the first instruction and the second instruction, so that the opening angle of the baffle plate of the reheater side flue can be adjusted by a small amplitude through the fifth instruction, the sixth instruction, the seventh instruction and the eighth instruction, and the flue gas quantity of high-temperature flue gas in the reheater side flue entering the inlet of the denitration device can be more accurately controlled.
The interval threshold value can only play a role in the range of catalytic reaction temperature (300-400 ℃), the effect of finely adjusting the angle of the reheater side flue baffle can be played, the opening angle of the reheater side flue baffle can be adjusted in the range of catalytic reaction temperature (300-400 ℃), the flue gas quantity of high-temperature flue gas in the reheater side flue entering the inlet of the denitration device is adjusted, the phenomenon that the temperature of the denitration device catalyst is changed too fast, mechanical damage to the catalyst can be caused is prevented, and the catalyst is protected.
Denitration catalyst entry flue gas temperature control requirement table in denitration full-load operation technology application process
| Catalyst inlet flue gas temperature | Rate of temperature rise of flue gas |
| Below 70 deg.C | ≤5℃/min |
| 70℃～120℃ | ≤10℃/min |
| Above 120 DEG C | ≤60℃/min |
Example 3
Referring to fig. 3, 5 to 6, a third embodiment of the present invention is based on the previous embodiment, in which a fuel is combusted in a furnace to generate high-temperature hot flue gas, a part of the heat is mainly transferred to a furnace water-cooled wall and a platen superheater in a radiation heat transfer manner, then the hot flue gas enters a rear shaft enclosure wall through a high-temperature superheater and a high-temperature reheater, a middle partition wall in the rear shaft enclosure wall divides the rear shaft into a front flue and a rear flue in parallel, a cold section reheater is arranged in the front flue, a low-temperature superheater and an economizer are arranged in the rear flue, the high-temperature gas in the furnace is introduced to detect the water temperature of a boiler through a thermometer, and steam of the deaerator is added during the water feeding period of the boiler to heat the water so as to increase the feed water temperature.
When the unit starts the boiler to feed water, auxiliary steam is added to the deaerator to heat, and the boiler feed water temperature is controlled to be 80-90 ℃ according to the auxiliary steam consumption. The auxiliary steam supply sufficient unit can increase the heating steam consumption of the deaerator and increase the water supply temperature to over 140 ℃. The feed water temperature is improved, the temperature difference between the economizer and the flue gas at the tail part of the flue is reduced, the heat exchange quantity of the flue gas is reduced, and the inlet temperature of the denitration device is quickly improved.
Increase the reserve appearance gas source of the high check valve that adds of #2 and optimize high operation time, increase the reserve appearance gas source of the high check valve that adds of #2, after the boiler ignition during the unit starts, open the reserve appearance gas source of the high check valve that adds of #2 and bleed, close normal appearance gas source, in time put into operation #2 high pressure, promote feedwater temperature as early as possible.
The tail part of the boiler is of a double-flue structure, the middle part of the boiler is provided with a middle partition wall, and the distribution of the flue gas amount of the front wall and the rear wall of the tail flue is adjusted in the starting process of the unit through the opening control of the flue gas adjusting baffle of the reheater, so that the heat exchange amount of the flue gas and the low-second, low-pass and economizer can be adjusted. The flue gas is ensured to basically pass through a low secondary area tube panel by adjusting the reheater flue gas adjusting baffle plate in the starting process of the unit, and the heat exchange with the economizer is reduced as much as possible. Before the boiler was igniteed among the unit start-up process, opened high low pressure bypass, along with the boiler intensification steps up, low temperature risees gradually again, and low again is few with flue gas heat transfer volume, is favorable to improving denitrification facility entry temperature.
It is important to note that the construction and arrangement of the present application as shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters (e.g., temperatures, pressures, etc.), mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited in this application. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of this invention. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. In the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present inventions. Therefore, the present invention is not limited to a particular embodiment, but extends to various modifications that nevertheless fall within the scope of the appended claims.
Moreover, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not be described (i.e., those unrelated to the presently contemplated best mode of carrying out the invention, or those unrelated to enabling the invention).
It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.
It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.
Claims (10)
1. The denitration full-load operation control method of the coal-fired unit is characterized by comprising the following steps of: comprises the steps of (a) preparing a mixture of a plurality of raw materials,
Detecting the gas temperature at the inlet of the denitration device through a temperature detector, and inputting the detected gas temperature into a controller through the temperature detector;
a temperature threshold value is preset in the controller, the gas temperature is compared with the temperature threshold value, and the controller sends an instruction to the smoke regulation controller;
and the flue gas adjusting controller adjusts the opening angle of a reheater side flue baffle in the double flues at the tail part of the boiler according to the instruction, and adjusts the amount of gas of high-temperature gas in the reheater side flue entering the inlet of the denitration device.
2. The coal-fired unit denitration full-load operation control method as set forth in claim 1, characterized in that:
a first temperature threshold and a second temperature threshold are arranged in the controller, and the second temperature threshold is higher than the first temperature threshold;
the controller compares the gas temperature detected by the temperature detector with a first temperature threshold value, wherein the gas temperature is less than the first temperature threshold value;
the controller sends a first instruction to the smoke adjusting baffle;
the flue gas regulation controller receives a first instruction and controls a reheater side flue baffle to increase an opening angle;
the amount of high temperature flue gas entering the inlet of the denitrification device is increased, and the temperature of the denitrification device is increased to reach the catalytic temperature.
3. The coal-fired unit denitration full-load operation control method as set forth in claim 2, characterized in that:
the controller compares the gas temperature detected by the temperature detector with a first temperature threshold value, and the gas temperature is greater than the first temperature threshold value;
the controller compares the gas temperature detected by the temperature detector with a second temperature threshold value, and the gas temperature is greater than the second temperature threshold value;
the controller sends a second instruction to the smoke adjusting baffle;
the smoke regulation controller receives a second instruction and controls the flue plate at the side of the reheater to reduce the opening angle;
the high-temperature flue gas volume that gets into the denitrification facility entry reduces, and denitrification facility temperature reduces relatively.
4. The coal-fired unit denitration full-load operation control method as set forth in claim 3, characterized in that: after receiving the first instruction, the smoke regulation controller sends a third instruction to the regulation valve;
the regulating valve receives a third instruction to open and opens the auxiliary steam main pipe;
the steam in the auxiliary steam main pipe enters a deaerator to heat water in the deaerator;
after the deaerator removes oxygen in water, the water heated in the deaerator conveys the water into the high-pressure heater through the water pump;
the high-pressure heater is internally pumped into the economizer after being secondarily heated by high-pressure steam extraction, so that the temperature of water supply in the economizer is increased.
5. The coal-fired unit denitration full-load operation control method as set forth in claim 4, characterized in that:
after receiving the second instruction, the smoke regulation controller sends a fourth instruction to the regulation valve;
and the regulating valve receives a fourth instruction to close and seals the auxiliary steam main pipe.
6. The coal-fired unit denitration full-load operation control method as set forth in claim 5, characterized in that:
the temperature detector continuously detects the gas temperature at the inlet of the denitration device, and the detection intervals are the same time period every time.
7. The coal-fired unit denitration full-load operation control method as set forth in claim 1, characterized in that:
an interval threshold value is also arranged in the controller;
the controller compares the gas temperature detected by the temperature detector with a first temperature threshold value, and the gas temperature is greater than the first temperature threshold value;
the controller compares the gas temperature detected by the temperature detector with a second temperature threshold value, wherein the gas temperature is less than the second temperature threshold value;
and the controller subtracts the gas temperature detected by the temperature detector from the gas temperature detected last time, and calculates to obtain the temperature difference.
8. The coal-fired unit denitration full-load operation control method as set forth in claim 7, characterized in that:
The temperature difference is a positive value;
the controller accesses the interval threshold;
the controller compares the temperature difference with an interval threshold value, and the absolute value of the temperature difference is greater than the absolute value of the interval threshold value;
the controller sends a fifth instruction to the smoke adjusting baffle;
the flue gas regulation controller receives a fifth instruction, and reduces the opening angle of a reheater side flue baffle;
the controller accesses the interval threshold;
comparing the temperature difference with an interval threshold, wherein the absolute value of the temperature difference is smaller than the absolute value of the interval threshold;
the controller regulates a sixth instruction of the baffle plate for the flue gas;
and the smoke regulation controller receives and sends a sixth instruction to reduce the opening angle of the reheater side flue damper.
9. The coal-fired unit denitration full-load operation control method as set forth in claim 8, characterized in that:
the temperature difference is a negative value;
the controller accesses the interval threshold;
the controller compares the temperature difference with an interval threshold value, and the absolute value of the temperature difference is greater than the absolute value of the interval threshold value;
the controller sends a seventh instruction to the smoke adjusting baffle;
the flue gas regulation controller receives a seventh instruction and increases the opening angle of a reheater side flue baffle;
the controller accesses the interval threshold;
The controller compares the temperature difference with an interval threshold value, and the absolute value of the temperature difference is smaller than the absolute value of the interval threshold value;
the controller sends an eighth instruction to the smoke adjusting baffle;
and the flue gas regulation controller receives an eighth instruction and increases the opening angle of the reheater side flue damper.
10. The coal-fired unit denitration full-load operation control method as set forth in claim 9, characterized in that: the flue gas adjusting controller receives a sixth instruction and an eighth instruction, and the adjusting angle of the reheater side flue damper is smaller than the adjusting angle when the fifth instruction and the seventh instruction are received;
and the adjustment angle of the smoke adjustment controller receiving the fifth instruction, the sixth instruction, the seventh instruction and the eighth instruction is far smaller than the adjustment angle of the smoke adjustment controller receiving the first instruction and the second instruction.
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