CN115475514B - Control system for pre-controlling denitration efficiency of gas boiler by using heat value and flow - Google Patents
Control system for pre-controlling denitration efficiency of gas boiler by using heat value and flow Download PDFInfo
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- CN115475514B CN115475514B CN202211278533.7A CN202211278533A CN115475514B CN 115475514 B CN115475514 B CN 115475514B CN 202211278533 A CN202211278533 A CN 202211278533A CN 115475514 B CN115475514 B CN 115475514B
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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
- B01D53/74—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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- 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
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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
- F23J15/003—Arrangements of devices for treating smoke or fumes for supplying chemicals to fumes, e.g. using injection devices
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D7/00—Control of flow
- G05D7/06—Control of flow characterised by the use of electric means
- G05D7/0617—Control of flow characterised by the use of electric means specially adapted for fluid materials
- G05D7/0629—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means
- G05D7/0635—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means by action on throttling means
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/206—Ammonium compounds
- B01D2251/2067—Urea
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
- B01D2258/02—Other waste gases
- B01D2258/0283—Flue gases
Abstract
The invention relates to the field of tail gas nitrogen oxide treatment. A control system for pre-controlling denitration efficiency of a gas boiler by utilizing heat value and flow rate is characterized in that urea solution is subjected to pyrolysis in a pyrolysis furnace to be decomposed into ammonia water, and the ammonia water is sprayed into SCR (selective catalytic reduction) and nitrogen oxides in tail gas by a nozzle to react, so that the content of nitrogen oxides at a chimney outlet meets emission requirements, a flowmeter is arranged on a converter and/or coke oven gas pipeline, a heat value meter is arranged on a mixed gas pipeline, and a PID (proportion integration differentiation) regulator regulates the opening of a urea inlet regulating valve according to CEMS (continuous flow rate) and/or converter and/or coke oven gas flow rate and the heat value of the mixed gas, thereby controlling the flow rate of urea.
Description
Technical Field
The invention relates to the field of tail gas nitrogen oxide treatment.
Background
Along with the increasing strictness of environmental protection laws and regulations and restriction standards, in order to prevent the pollution of the environment by excessive nitrogen oxides generated after the combustion of gas media in the boiler, the denitration treatment of the boiler tail gas should be carried out. At present, the technology is mature, and a denitration system adopts a Selective Catalytic Reduction (SCR) method to achieve the purpose of removing nitrogen oxides in flue gas.
1. Principle of reaction
The SCR reactor is arranged between two groups of economizers of the boiler, and is sprayed into the boiler through a spray pipe grid to react with catalysts arranged on two sides after pyrolysis of urea solution, so that the aim of flue gas denitration is fulfilled. Principle of chemical reaction:
CO(NH 2 ) 2 →NH 3 +hcno (isocyanatoamine), which decomposes at 160 degrees celsius;
4NO+4NH 3 +O 2 →4N 2 +6H 2 O；
6NO 2 +8NH 3 →7N 2 +12H 2 O。
2. reactor for producing a catalyst
The pressure drop design value of the newly-installed catalyst of the engineering denitration device is 300Pa for each layer, 600Pa for two layers, and when the pressure drop exceeds 720Pa, the system sends out a differential pressure high-level alarm signal. The alarm set point is set according to the initial installation of 2 layers of catalysts.
3. Ammonia injection system
An ammonia injection grid provides gaseous ammonia to an SCR reactor. The ammonia/air mixture from the pyrolysis system is sprayed into the inlet flue in front of the superior economizer through 8 branch pipes on a main pipe. Each branch pipe is provided with a manual regulating valve, and the ammonia spraying amount of each branch pipe can be manually regulated according to the actual distribution condition of the flue gas in the initial operation stage, so that the ammonia spraying flow of each nozzle is matched with the NOx concentration of the coverage area of the ammonia spraying flow. After the adjustment, the opening of the manual regulating valve is fixed, and the adjustment is not carried out later.
The DCS control system utilizes the concentration of NOx at the total exhaust port of the unit to adjust a urea solution regulating valve to control the ammonia injection amount.
The urea solution is utilized from a storage tank of the existing 300MW unit equipment, and 2 urea solution circulating pumps are newly added to provide stable urea solution for the denitration system for one preparation.
4. Problems exist
Whenever converter (or coke oven) gas enters the boiler for combustion, the concentration of nitrogen oxides in the tail gas of the boiler is increased, and the greater the flow of the converter (or coke oven) gas is, the greater the concentration of nitrogen oxides in the tail gas of the boiler is, so that out-of-standard emission is often generated. Because the exceeding standard has to adopt measures for reducing the load of the boiler to achieve the compliance emission, the production and the environmental protection are greatly affected.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: without major modification, the existing equipment and PID regulator are used to realize the treatment of the nitrogen oxides in the tail gas when the converter and/or coke oven gas enters the boiler for combustion.
The technical scheme adopted by the invention is as follows: a control system for denitration efficiency of a gas boiler by utilizing heat value and flow pre-control is characterized in that after mixed gas is formed by mixing blast furnace gas and converter and/or coke oven gas and combusted in a hearth, generated tail gas is sequentially discharged into air through a chimney through SCR denitration and desulfurization tower desulfurization, CEMS is arranged at the mouth of the chimney, a blast furnace gas flowmeter is arranged on a blast furnace gas pipeline, ammonia gas which is easily generated by pyrolyzing urea through a pyrolysis furnace in the SCR denitration process reacts with nitrogen oxides in the tail gas, the blast furnace gas is used as main fuel, converter and/or coke oven gas is randomly introduced at any time, the inlet quantity and time of the converter and/or coke oven gas are unpredictable, the opening of a urea inlet regulating valve is regulated through a PID regulator according to the detection result of the CEMS, so that the flow of urea is controlled, urea solution is subjected to pyrolysis decomposition into ammonia water through a pyrolysis furnace, the nitrogen oxides in the tail gas are sprayed into the SCR through a nozzle, the content of nitrogen oxides at the outlet of the chimney meets the emission requirement, a flowmeter is arranged on the converter and/or coke oven gas pipeline, the PID regulator is arranged on the pipeline, and the heat value of the converter and/or coke oven gas is regulated according to the heat value, so that the heat value of the mixed gas is greatly regulated, and the heat value of the converter and/or coke oven gas is regulated.
Urea solution flow Q when the converter and/or coke oven gas flow is 0 Urea Satisfy the formula Q Urea =f（Q Blast furnace ，P），Q Blast furnace For blast furnace gas flow, P is the content of nitrogen oxides detected by CEMS at the chimney mouth, and f () is the internal logic formula of the PID regulator; urea solution flow Q when the converter and/or coke oven gas flow is not 0 Urea Satisfy the formula Q Urea =f（Q Blast furnace +k*Q Coke turning P), wherein k is a constant, the value of Q is 0.1-10 Coke turning The sum of the flow rates of the converter gas and the coke oven gas.
When the flow rate of the converter and/or coke oven gas is not 0Urea solution flow rate Q Urea The correction value of (1) satisfies the formula, Q Urea =f（Q Blast furnace +d*k*Q Coke turning P), d is the correction factor, d=j total/(J) Blast furnace +J Coke turning ) Wherein J is the heat value measured by a heat value meter on a pipeline of the mixed gas Blast furnace For blast furnace gas flow Q Blast furnace Converted value, J Coke turning For the flow rate and Q of converter and coke oven gas Coke turning The value of the conversion.
When the flow rate and Q of the converter gas and the coke oven gas are Coke turning When the flow rate of the converter and the coke oven gas is larger than or equal to the set maximum value, alarming and prompting an operator to perform key observation, and timely processing when abnormality is found; when the heat value J total measured by a heat value instrument on a mixed gas pipeline is larger than or equal to the maximum set value of the mixed gas heat value, an alarm prompts an operator to perform key observation, and the abnormality is found and timely treated.
The abnormal detection is that the CEMS detection result cannot meet the emission requirement, the processing in the step refers to reducing the flow of the blast furnace gas, after reducing the flow of the blast furnace gas by 5%, observing whether the CEMS detection result meets the emission requirement after 5 minutes, and if the CEMS detection result does not meet the requirement, continuing to reduce the flow of the blast furnace gas by 5%, until the CEMS detection result meets the emission requirement after 5 minutes.
The beneficial effects of the invention are as follows: the control system for pre-controlling the denitration efficiency of the gas boiler by utilizing the heat value of the mixed gas and the flow of the converter and/or the coke oven gas is modified in the original denitration control loop, and aims to solve the problems that the gas boiler has extremely unstable gas components due to the change of the working condition of a blast furnace (or a converter), the existing control system cannot timely adjust the ammonia injection amount, the denitration efficiency is influenced, and the exceeding emission of nitrogen oxides is often caused. The system is added with the mixed gas heat value and the converter and coke oven gas flow detection device as feedforward control signals, and can timely adjust the ammonia spraying amount according to the increase of the converter and/or coke oven gas flow (or the mixed gas heat value), so that the denitration efficiency is greatly ensured; and the heat value and flow change logic judgment is set, so that an advanced reminding effect is achieved for operators and a control system, and parameter exceeding is avoided.
Drawings
FIG. 1 is a schematic flow chart of the present invention;
fig. 2 is a schematic flow diagram of the prior art.
Description of the embodiments
As shown in fig. 2, the working principle of the original denitration control system of the 80MW unit is as follows:
under normal conditions, a large amount of stable blast furnace gas enters a boiler for combustion, and the tail gas firstly absorbs nitrogen oxides through a denitration device (SCR) and then absorbs SO through a desulfurization device 2 Absorbing and finally discharging to the atmosphere through a chimney. In the process, the denitration control system compares detection data of the concentration of the nitrogen oxides with an artificial set value through the CEMS at the tail end, and then adjusts the opening of the regulating valve through the PID regulator, so that the flow of urea is controlled, urea solution is decomposed into ammonia water through pyrolysis of the pyrolysis furnace, and the ammonia water is sprayed into the SCR device to react with and absorb the nitrogen oxides in the tail gas through the nozzle, so that the compliance emission of the nitrogen oxides is achieved.
However, in the actual process, converter (or coke oven) gas can be introduced into blast furnace gas through a pipeline at any time to enter a boiler for combustion, so that the temperature of a hearth and the temperature of tail gas are greatly increased, and at the moment, the nitrogen oxide concentration detection has lag of 5-7 minutes due to the fact that the space distance from the hearth to CEMS monitoring points is far, and an operator can modify the set value of the PID regulator according to the data until CEMS measures the nitrogen oxide concentration, and meanwhile, the opening of a regulating valve and the flow of urea are changed, and the lag control mode inevitably leads to the increase of the concentration of NOx or the exceeding emission.
Aiming at an 80MW unit newly put into use in 2021 of a certain factory, during the operation of a boiler denitration system in nearly one year, because the gas composition is extremely unstable due to the random change of the working condition of a blast furnace (or a converter), the existing control system (due to medium transmission and inertia of a process) cannot timely adjust the ammonia injection amount, thereby influencing the denitration effect and often causing an environmental protection event of exceeding NOx index emission, the improvement of the existing control system is very necessary, and the proposal for improving the control system for pre-controlling the denitration efficiency of the gas boiler by using the heat value and the flow is particularly provided. The lower graph shows the superscalar data recorded by the 20220327CEMS system.
According to the over-standard data of the day 27 of 3 of 2022 and the analysis of the variation of the converter gas at the same time, the converter gas consumption is gradually increased (namely the boiler combustion gas component is fluctuated) when the 80MW unit exceeds the standard, and meanwhile the nitrogen oxide content in the tail gas of the boiler is increased along with the fluctuation, and finally exceeds the standard.
The following table is a comparison table of the composition changes of blast furnace gas and converter gas.
From the above table, it can be seen that CO and H are present in the coke oven gas and the converter gas 2 The ratio of the nitrogen oxide to the coke oven gas is relatively large, and the content of the nitrogen oxide is far higher than that of the blast furnace gas, so that when the blast furnace gas is combusted, if a large amount of coke oven gas (or converter gas) is suddenly added, extremely high heat is generated, the temperature of the flue gas is rapidly increased, and the concentration of the nitrogen oxide is rapidly increased until the nitrogen oxide exceeds the standard.
According to the requirements of the document 856 of the Shanxi province environment protection hall jin ring function [ 2015 ]: ultralow emission of the gas boiler is that under the condition of the standard oxygen content of 3 percent, the emission concentration of nitrogen oxides is less than 50mg/m 3 。
Aiming at the process characteristics and environmental protection requirements, the invention provides a control system for pre-controlling the denitration efficiency of a gas boiler by using the heat value and the flow, which aims to solve the problem that the control system can adjust the ammonia injection amount in time due to the random change of the gas components, eliminate the control hysteresis phenomenon, ensure the denitration efficiency and ensure that the nitrogen oxides reach the emission standards.
As shown in fig. 1, in order to solve the problems of control lag and exceeding standard in the prior art, the production process of denitration and gas components is comprehensively known and mastered:
the first and blast furnace gas is the main fuel of the boiler, and the converter and/or coke oven gas can be randomly added at any time according to the production working conditions of the converter and/or coke oven;
the time and the size of the random participation of the second, converter and/or coke oven gas at any time are unpredictable;
thirdly, the space distance from the hearth to the CEMS monitoring point is far, and the nitrogen oxide concentration detection has lag of 5-7 minutes;
from among the multiple superscalar events, it is concluded that: the nitrogen oxide concentration detection has lag of 5-7 minutes when the gas component randomly changes at any time and exceeds the standard, and the change trend and the change amplitude of the gas component must be predicted or early-warned in advance, so that the ammonia injection quantity can be changed in advance to ensure that the nitrogen oxide concentration cannot exceed the standard.
Based on the above consideration, the design concept of the novel control system is as follows:
a control system for pre-controlling denitration efficiency of a gas boiler by utilizing heat value and flow rate is characterized in that after blast furnace gas and converter and/or coke oven gas are mixed to form mixed gas, the mixed gas is combusted in a hearth, the generated tail gas is sequentially discharged into air through a chimney through SCR denitration and desulfurization tower desulfurization, a CEMS is arranged at the mouth of the chimney, a blast furnace gas flowmeter is arranged on a blast furnace gas pipeline, ammonia gas which is easily generated by pyrolyzing urea through a pyrolysis furnace in the SCR denitration process reacts with nitrogen oxides in the tail gas, the blast furnace gas is used as main fuel, the converter and/or coke oven gas is randomly introduced at any time, the introduction amount and time of the converter and/or coke oven gas are unpredictable, the opening degree of a urea inlet regulating valve is regulated through a PID regulator according to the detection result of the CEMS, so that the flow rate of urea is controlled, urea solution is subjected to pyrolysis decomposition into ammonia water through the pyrolysis furnace, the nitrogen oxides in the tail gas are sprayed into the SCR through a nozzle, so that the content of the nitrogen oxides at the chimney outlet meets the emission requirement, a flowmeter is arranged on the converter and/or the coke oven gas pipeline (so that flow rate signals can be displayed when the converter and/or the coke oven gas is/are introduced, the flow rate signals can be displayed, and the mixed gas concentration is predicted, and the flow rate of the mixed gas is greatly changed, and the heat value of the urea is regulated according to the heat value of the converter and/or the heat value is greatly changed, and the heat value of the mixed gas is or the heat value is regulated.
When the gas flow of the converter is increased, the urea regulating valve is opened to increase the ammonia injection amount of the SCR, so that the concentration of nitrogen oxides is reduced; when the flow signal of the converter and/or the coke oven is reduced, the urea regulating valve is closed down, and the ammonia injection amount of the SCR is reduced, so that the concentration of nitrogen oxides is increased.
Urea solution flow Q when the converter and/or coke oven gas flow is 0 Urea Satisfy the formula Q Urea =f（Q Blast furnace ，P），Q Blast furnace For blast furnace gas flow, P is the content of nitrogen oxides detected by CEMS at the chimney mouth, and f () is the internal logic formula of the PID regulator (prior art); urea solution flow Q when the converter and/or coke oven gas flow is not 0 Urea Satisfy the formula Q Urea =f（Q Blast furnace +k*Q Coke turning P), wherein k is a constant, the value of Q is 0.1-10 Coke turning The sum of the flow rates of the converter gas and the coke oven gas.
Urea solution flow Q when the converter and/or coke oven gas flow is not 0 Urea The correction value of (1) satisfies the formula, Q Urea =f（Q Blast furnace +d*k*Q Coke turning P), d is the correction factor, d=j total/(J) Blast furnace +J Coke turning ) Wherein J is the heat value measured by a heat value meter on a pipeline of the mixed gas Blast furnace For blast furnace gas flow Q Blast furnace Converted value, J Coke turning For the flow rate and Q of converter and coke oven gas Coke turning The value of the conversion.
When the flow rate and Q of the converter gas and the coke oven gas are Coke turning When the flow rate of the converter and the coke oven gas is larger than or equal to the set maximum value, alarming and prompting an operator to perform key observation, and timely processing when abnormality is found; when the heat value J total measured by a heat value instrument on a mixed gas pipeline is larger than or equal to the maximum set value of the mixed gas heat value, an alarm prompts an operator to perform key observation, and the abnormality is found and timely treated. Adding logic judgment and alarm functions: when the converter gas flow signal is more than or equal to 3000m 3 When/h, or when the calorific value is 3700 or morekJ/m 3 And when the image is displayed, the alarm is given to prompt an operator to perform key observation, and the abnormality is found and timely processed.
The abnormal detection is that the CEMS detection result cannot meet the emission requirement, the processing in the step refers to reducing the flow of the blast furnace gas, after reducing the flow of the blast furnace gas by 5%, observing whether the CEMS detection result meets the emission requirement after 5 minutes, and if the CEMS detection result does not meet the requirement, continuing to reduce the flow of the blast furnace gas by 5%, until the CEMS detection result meets the emission requirement after 5 minutes.
One example is as follows:
1) A flow detection device (venturi) spare part program declared at the end of month 12 of 2021; the spare part of 2022 was returned, and a venturi restriction was installed on the converter gas piping (coke oven gas was not considered in this example) remote from the boiler, so that a signal of gas composition change was detected as early as possible.
2) The heat value instrument uses original spare parts and is arranged on a pipeline after mixing converter gas and blast furnace gas so as to accurately measure the change of the heat value of a medium; a differential pressure transmitter is installed at the venturi.
3) And laying cable bridges and signal and power cables from the Venturi to the DCS control cabinet and from the heat value instrument to the DCS control cabinet.
4) Checking the cables listed in 3) and wiring in situ and in the DCS cabinet.
5) And displaying the flow rate of the converter gas and the calorific value of the mixed gas. Establishing a one-to-one correspondence between related variables and picture display and writing logic judgment that the related variables are about to change: the flow rate of the converter gas is more than or equal to 3000m 3 /h (calorific value of mixed gas is more than or equal to 3700 KJ/m) 3 ) The alarm is started, and the alarm is accompanied with digital reddening, flashing, sound and the like, so as to play a role in warning an operator.
6) And programming a control program of the primary and secondary PID regulator and making a regulator operation picture. The primary regulator adopts deviation regulation, and the secondary regulator adopts positive value regulation. And taking the converter gas flow and the mixed gas heat value as feedforward signals. The regulator output signal may control a urea flow regulator valve.
7) Dotting and static debugging. Setting parameters such as differential pressure range, measuring unit, pressure guiding mode, signal output mode and the like of the newly added differential pressure transmitter one by one; and performing tightness detection, power-on preheating, ignition time, signal output and other parameter settings on the heat value instrument. After the on-site instrument is set, dotting is carried out on the DCS images one by one. And performing ignition test operation on the heat value instrument until the heat value instrument works stably.
8) A historical database of relevant monitoring parameters is added. And establishing a historical database for related variables such as converter gas flow, urea flow, heat value, NOx concentration and the like.
9) And dynamically debugging and controlling the system to be used. And (3) performing trial casting of a new control system during the operation of the boiler, and respectively debugging PI values of the primary and secondary PID regulators, so that the control system can timely follow the change of the feedforward signal, and the NOx concentration is ensured not to exceed the standard.
The novel control system is added with the mixed gas heat value and the converter gas flow detection device as feedforward control signals, and can timely adjust the ammonia injection amount according to the increase of the converter gas amount (or the mixed gas heat value), so that the denitration efficiency is greatly ensured; and the heat value and flow change logic judgment is set, so that an advanced reminding effect is achieved for operators and a control system, and parameter exceeding is avoided.
Claims (3)
1. A control system for pre-controlling denitration efficiency of a gas boiler by utilizing heat value and flow is characterized in that after blast furnace gas and converter and/or coke oven gas are mixed to form mixed gas to be combusted in a hearth, the generated tail gas is sequentially discharged into air through a chimney through SCR denitration and desulfurization tower desulfurization, a CEMS is arranged at the mouth of the chimney, a blast furnace gas flowmeter is arranged on a blast furnace gas pipeline, in the SCR denitration process, ammonia gas which is easily generated by pyrolyzing urea through a pyrolysis furnace reacts with nitrogen oxides in the tail gas, the denitration is carried out, wherein the blast furnace gas is used as main fuel, the converter and/or coke oven gas is randomly introduced at any time, the introduction amount and time of the converter and/or coke oven gas are unpredictable, the opening degree of a urea inlet regulating valve is regulated through a PID regulator according to a CEMS detection result, so that the flow of urea is controlled, and urea solution is subjected to pyrolysis decomposition through the pyrolysis furnaceThe ammonia water is formed, the nitrogen oxides in the SCR and the tail gas are sprayed into the nozzle to react, so that the content of the nitrogen oxides at the outlet of the chimney meets the emission requirement, and the method is characterized in that: a flowmeter is arranged on a converter and/or coke oven gas pipeline, a heat value instrument is arranged on a mixed gas pipeline, and a PID regulator adjusts the opening of a urea inlet regulating valve according to CEMS, converter and/or coke oven gas flow and mixed gas heat value regulation, so as to control the flow of urea; urea solution flow Q when the converter and/or coke oven gas flow is 0 Urea Satisfy the formula Q Urea =f（Q Blast furnace ，P），Q Blast furnace For blast furnace gas flow, P is the content of nitrogen oxides detected by CEMS at the chimney mouth, and f () is the internal logic formula of the PID regulator; urea solution flow Q when the converter and/or coke oven gas flow is not 0 Urea Satisfy the formula Q Urea =f（Q Blast furnace +k*Q Coke turning P), wherein k is a constant, the value of Q is 0.1-10 Coke turning The flow sum of the converter gas and the coke oven gas; urea solution flow Q when the converter and/or coke oven gas flow is not 0 Urea The correction value of (1) satisfies the formula, Q Urea =f（Q Blast furnace +d*k*Q Coke turning P), d is the correction factor, d=j total/(J) Blast furnace +J Coke turning ) Wherein J is the heat value measured by a heat value meter on a pipeline of the mixed gas Blast furnace For blast furnace gas flow Q Blast furnace Converted value, J Coke turning For the flow rate and Q of converter and coke oven gas Coke turning The value of the conversion.
2. The control system for pre-controlling denitration efficiency of gas boiler by using heat value and flow according to claim 1, wherein: when the flow rate and Q of the converter gas and the coke oven gas are Coke turning When the flow rate of the converter and the coke oven gas is larger than or equal to the set maximum value, alarming and prompting an operator to perform key observation, and timely processing when abnormality is found; when the heat value J total measured by a heat value instrument on a mixed gas pipeline is larger than or equal to the maximum set value of the mixed gas heat value, an alarm prompts an operator to perform key observation, and the abnormality is found and timely treated.
3. The control system for pre-controlling denitration efficiency of gas boiler by using heat value and flow according to claim 2, wherein: the abnormal detection is that the CEMS detection result cannot meet the emission requirement, the processing in the step refers to reducing the flow of the blast furnace gas, after reducing the flow of the blast furnace gas by 5%, observing whether the CEMS detection result meets the emission requirement after 5 minutes, and if the CEMS detection result does not meet the requirement, continuing to reduce the flow of the blast furnace gas by 5%, until the CEMS detection result meets the emission requirement after 5 minutes.
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| JP2014095294A (en) * | 2012-11-07 | 2014-05-22 | Toyota Industries Corp | Exhaust emission control system |
| CN105137947A (en) * | 2015-09-15 | 2015-12-09 | 湖南千盟智能信息技术有限公司 | Intelligent control and management system for coke oven |
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