Coke oven flue gas denitration system

Abstract

The application discloses a coke oven flue gas denitration system and relates to the technical field of denitration. The system comprises a coke cake temperature analysis module, a flue gas double depletion control module, a gas flow control module and a combustion chamber temperature detection module connected with a data terminal. The flue gas double depletion control module comprises an induced draft fan which is used for leading part of flue gas in a branch flue out of the branch flue. The first premixing chamber in the gas flow control module is used for mixing flue gas with air, and the second premixing chamber is used for mixing flue gas with coke oven gas. The data terminal is used for adjusting the uniformity of coke cake temperature distribution when the uniformity of coke cake temperature distribution exceeds a first preset range, and adjusting the uniformity of fire channel temperature distribution in the combustion chamber by adjusting the frequency of the induced draft fan and the opening of the flow regulating valve when the uniformity of fire channel temperature distribution in the combustion chamber exceeds a second preset range. The application reduces the emission of nitrogen oxides.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of denitration, in particular to a coke oven flue gas denitration system. BACKGROUND

[0002] The main pollutants of coke oven flue gas include nitrogen oxides (NO x ), sulfides, etc., and nitrogen oxides and sulfides are important sources of air pollution. x Among them, NO x generated in the combustion chamber of the coke oven accounts for the main source. Temperature is the main factor for the generation of thermal NO x . In theory, when the temperature is higher than 1600℃, NO x increases rapidly in an exponential law, and otherwise, almost no nitrogen oxides are generated. It has been proven that in order to ensure the quality of coke, the temperature in the combustion chamber of the coke oven should not be lower than 1350℃. Therefore, ensuring the uniformity of the temperature in the combustion chamber of the coke oven and avoiding local overheating are important means to reduce nitrogen oxides.

[0003] The combustion phenomenon occurring in the combustion chamber of the coke oven in the industry at present belongs to diffusion combustion, and there is a phenomenon that the combustion temperature is not uniform and the local combustion temperature is too high, thereby causing a large increase in thermal NO x . This diffusion combustion is a extensive use of energy, and at the same time, it causes adverse effects on the environment. Since the coke oven vertical fire channel has a narrow and limited space structure, that is, the height size of the vertical fire channel is much larger than the lateral size thereof, thereby causing the combustion process in the vertical fire channel to basically occur at the fuel outlet position at the bottom of the vertical fire channel, so that a local high temperature phenomenon is formed in the vertical fire channel. The excessive longitudinal temperature difference is not conducive to the formation of high-quality coke. In addition, the high-temperature combustion process causes a large amount of thermal NO x to be generated, thereby causing serious environmental pollution and becoming a difficult problem to be solved at present. SUMMARY

[0004] The purpose of the present application is to provide a coke oven flue gas denitration system, which reduces the emission of nitrogen oxides.

[0005] To achieve the above purpose, the present application provides the following scheme:

[0006] A coke oven flue gas denitration system, comprising: a data terminal, and a coke cake temperature analysis module, a flue gas double depletion control module, a gas flow control module and a combustion chamber temperature detection module connected with the data terminal;

[0007] The coke cake temperature analysis module is used to determine the uniformity of the coke cake temperature distribution;

[0008] The flue gas double-lean control module comprises an induced draft fan, which is used to draw part of the flue gas in the branch flue from the branch flue;

[0009] The gas flow control module comprises a first premixing chamber, a second premixing chamber, a first flow regulating valve and a second flow regulating valve, the first inlet of the first premixing chamber is connected with the outlet of the induced draft fan through the first flow regulating valve, the first inlet of the second premixing chamber is connected with the outlet of the induced draft fan through the second flow regulating valve, the second inlet of the first premixing chamber is used to input air, the second inlet of the second premixing chamber is used to input coke oven gas, and the outlet of the first premixing chamber and the outlet of the second premixing chamber are both connected with the combustion chamber;

[0010] The combustion chamber temperature detection module is used to detect the fireway temperature distribution uniformity in the combustion chamber;

[0011] The data terminal is used to adjust the coke cake temperature distribution uniformity when the coke cake temperature distribution uniformity exceeds the first preset range, and adjust the fireway temperature distribution uniformity by adjusting the frequency of the induced draft fan, the opening of the first flow regulating valve and the opening of the second flow regulating valve when the fireway temperature distribution uniformity in the combustion chamber exceeds the second preset range.

[0012] Optionally, the coke cake temperature analysis module comprises a coke cake temperature uniformity analysis unit and a coke cake temperature detection probe at each site of the coke cake; the temperature signal detected by the coke cake temperature detection probe is sent to the coke cake temperature uniformity analysis unit, and the coke cake temperature uniformity analysis unit calculates the coke cake temperature distribution uniformity according to the received temperature signals.

[0013] Optionally, the calculation formula of the coke cake temperature distribution uniformity is as follows:

[0014]

[0015] Wherein, θ c represents the coke cake temperature distribution uniformity, T i,j represents the temperature of the i th coke cake site, T m,j represents the average temperature of the coke cake.

[0016] Optionally, the outlet of the second premixing chamber is connected with a third flow regulating valve;

[0017] The data terminal comprises a coke cake temperature distribution uniformity adjusting unit, which is used to reduce the opening of the third flow regulating valve or increase the frequency of the induced draft fan until the deviation of the coke cake temperature distribution uniformity from the target coke maturity model is less than 5% when the deviation of the coke cake temperature distribution uniformity from the target coke maturity model exceeds 5%.

[0018] Optionally, the formula for calculating the fire channel temperature distribution uniformity is:

[0019]

[0020] wherein θ h represents the fire channel temperature distribution uniformity, T k represents the temperature of the kth fire channel measurement site, T ave represents the fire channel average temperature.

[0021] Optionally, the data terminal comprises a fire channel temperature distribution uniformity adjusting unit, which is configured to increase the frequency of the induced draft fan, adjust the opening degree of the first flow regulating valve and the opening degree of the second flow regulating valve, and make the flue gas passing through the first flow regulating valve and the second flow regulating valve in a set proportion, until the fire channel temperature distribution uniformity is less than 15%, when the fire channel temperature distribution uniformity is greater than 15%.

[0022] Optionally, a first flow meter is arranged between the first flow regulating valve and the first inlet of the first premixing chamber, and a second flow meter is arranged between the second flow regulating valve and the first inlet of the second premixing chamber.

[0023] Optionally, the flue gas analysis module is further configured to detect the carbon monoxide concentration and the nitrogen oxide concentration in the flue gas, and send the detected carbon monoxide concentration and nitrogen oxide concentration to the data terminal.

[0024] The data terminal is further configured to increase the frequency of the induced draft fan, adjust the opening degree of the first flow regulating valve and the opening degree of the second flow regulating valve, and make the flue gas passing through the first flow regulating valve and the second flow regulating valve in a set proportion, until the carbon monoxide concentration is less than the first set value and the nitrogen oxide concentration is less than the second set value, when the carbon monoxide concentration is greater than the first set value or the nitrogen oxide concentration is greater than the second set value.

[0025] According to the specific embodiments of the present application, the following technical effects are provided:

[0026] The present application adjusts the flue gas emission rate of the flue channel by the induced draft fan, the first flow regulating valve and the second flow regulating valve, adjusts the coke cake temperature distribution uniformity and the fire channel temperature distribution uniformity, and recycles the flue gas emitted by the flue channel, thereby reducing the emission of nitrogen oxides. BRIEF DESCRIPTION OF DRAWINGS

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A schematic diagram of a coke oven flue gas denitrification system provided in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the physical structure of a coke oven flue gas denitrification system provided in an embodiment of the present invention.

[0030] Symbol explanation:

[0031] 1-Exhaust fan, 2-First flow regulating valve, 3-Second flow regulating valve, 4-Third flow regulating valve, 5-First flow meter, 6-Second flow meter, 7-Third flow meter. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] The purpose of this invention is to provide a coke oven flue gas denitrification system that reduces nitrogen oxide emissions.

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Example 1

[0036] like Figure 1 and Figure 2 As shown, this embodiment provides a coke oven flue gas denitrification system, including: a data terminal 101, and a coke cake temperature analysis module 102, a flue gas dual-leanification control module 103, a gas flow control module 104, and a combustion chamber temperature detection module 105 connected to the data terminal 101.

[0037] The coke cake temperature analysis module 102 is used to determine the uniformity of coke cake temperature distribution.

[0038] The flue gas double-lean control module 103 comprises an induced draft fan 1 for leading part of flue gas in the divided flue out of the divided flue. The led-out flue gas enters the gas flow control module 104 through the recirculation flue gas regulating valve (the first flow regulating valve 2 and the second flow regulating valve 3) and the recirculation flue gas flow meter (the first flow meter 5 and the second flow meter 6).

[0039] The gas flow control module 104 comprises a first premixing chamber, a second premixing chamber, the first flow regulating valve 2 and the second flow regulating valve 3, the first inlet of the first premixing chamber is connected with the outlet of the induced draft fan 1 through the first flow regulating valve 2, the first inlet of the second premixing chamber is connected with the outlet of the induced draft fan 1 through the second flow regulating valve 3, the second inlet of the first premixing chamber is used for inputting air, the second inlet of the second premixing chamber is used for inputting coke oven gas, and the outlet of the first premixing chamber and the outlet of the second premixing chamber are both connected with a combustion chamber.

[0040] The first premixing chamber is used for mixing flue gas and air and then inputting into the gas chamber. The second premixing chamber is used for mixing flue gas and coke oven gas and then inputting into the gas chamber.

[0041] The coke oven gas can be regulated through the third flow regulating valve 4 and the third flow meter 7, and the air flow can be regulated through the damper opening degree. The air flow can be determined through the gas (coke oven gas) flow and the air excess coefficient, and then the damper opening degree is changed.

[0042] The combustion chamber is composed of a plurality of fireways with a narrow and long limited space structure. In the absence of the flue gas double-lean control module 103, the combustion process in the fireway belongs to the conventional diffusion combustion control combustion state, that is, the chemical reaction rate is much higher than the component transfer rate, and a local high temperature phenomenon is easily formed at the lamp head position at the bottom of the fireway, and a large amount of NOx is generated x .

[0043] The combustion chamber temperature detection module 105 is used for fireway temperature detection, gas inlet temperature detection, air inlet temperature detection and recirculation flue gas temperature detection.

[0044] The combustion chamber temperature detection module 105 is used for determining the fireway temperature distribution uniformity in the combustion chamber according to the fireway temperature.

[0045] The data terminal 101 is used for adjusting the coke cake temperature distribution uniformity when the coke cake temperature distribution uniformity exceeds the first preset range, and adjusting the fireway temperature distribution uniformity by adjusting the frequency of the induced draft fan 1, the opening degree of the first flow regulating valve 2 and the opening degree of the second flow regulating valve 3 when the fireway temperature distribution uniformity in the combustion chamber exceeds the second preset range.

[0046] The coke cake temperature analysis module 102 comprises a coke cake temperature uniformity analysis unit and coke cake temperature detection probes at various positions of the coke cake; the temperature signals detected by the coke cake temperature detection probes are sent to the coke cake temperature uniformity analysis unit, and the coke cake temperature uniformity analysis unit calculates the coke cake temperature distribution uniformity according to the received temperature signals.

[0047] The formula for calculating the coke cake temperature distribution uniformity is as follows:

[0048]

[0049] wherein θ c represents the coke cake temperature distribution uniformity, T i,j represents the temperature of the i th coke cake position, T m,j represents the average temperature of the coke cake.

[0050]

[0051] wherein n represents the number of coke cake positions.

[0052] The outlet of the second premixing chamber is connected with a third flow regulating valve 4.

[0053] The data terminal 101 comprises a coke cake temperature distribution uniformity adjustment unit, which is configured to reduce the opening degree of the third flow regulating valve 4 or increase the frequency of the induced draft fan 1 until the deviation of the coke cake temperature distribution uniformity from the target coke maturity model is less than 5% when the deviation of the coke cake temperature distribution uniformity from the target coke maturity model exceeds 5% (the first preset range).

[0054] The formula for calculating the flue temperature distribution uniformity is as follows:

[0055]

[0056] wherein θ h represents the flue temperature distribution uniformity, T k represents the temperature of the k th flue measurement position, T ave represents the average temperature of the flue.

[0057]

[0058] wherein n' represents the number of flue measurement positions.

[0059] The data terminal 101 comprises a flue temperature distribution uniformity adjusting unit, which is used to increase the frequency of the induced draft fan 1, adjust the opening degree of the first flow adjusting valve 2 and the opening degree of the second flow adjusting valve 3, and make the flue gas passing through the first flow adjusting valve 2 and the second flow adjusting valve in a set proportion, until the flue temperature distribution uniformity is less than 15% when the flue temperature distribution uniformity is greater than 15% (second preset range).

[0060] The first flow adjusting valve 2 is provided with a first flow meter 5 between the first flow adjusting valve 2 and the first inlet of the first premixing chamber,

[0061] The second flow adjusting valve 3 is provided with a second flow meter 6 between the second flow adjusting valve 3 and the first inlet of the second premixing chamber.

[0062] A coke oven flue gas denitration system further comprises a flue gas analysis module for detecting the oxygen, carbon monoxide concentration and nitrogen oxide concentration in the flue, and sending the detected carbon monoxide concentration and nitrogen oxide concentration to the data terminal 101.

[0063] The data terminal 101 is further used to increase the frequency of the induced draft fan 1, adjust the opening degree of the first flow adjusting valve 2 and the opening degree of the second flow adjusting valve 3, and make the flue gas passing through the first flow adjusting valve 2 and the second flow adjusting valve in a set proportion, until the carbon monoxide concentration is less than the first set value and the nitrogen oxide concentration is less than the second set value, when the carbon monoxide concentration is greater than the first set value or when the nitrogen oxide concentration is greater than the second set value.

[0064] The data terminal 101 detects and controls the combustion chamber temperature detection module 105, the gas flow control module 104, the flue gas double depletion control module 103 and the flue gas analysis module, and the detection and control adopts a time sequence control method.

[0065] The time sequence control method specifically comprises the following steps.

[0066] First sequence control: the first time sequence controller measures the coke cake temperature online in real time, and the temperature value of each site is fed back to the data terminal to analyze and calculate the coke cake temperature distribution uniformity.

[0067] Further, the coke cake site temperature T i,j Firstly, the target coke maturity model should be met, if T i,j If the condition is not met, the feedback is directly to the data terminal for debugging, and when the target coke maturity model is met, the coke cake temperature is analyzed and calculated for temperature distribution uniformity, and then the result is fed back to the data terminal for next step debugging.

[0068] Second sequence control: according to the coke oven temperature distribution uniformity result obtained by the first sequence control, the temperature of each fireway in the coke oven combustion chamber is measured, and after the temperature value of each site is fed back to the data terminal, the temperature distribution uniformity of each fireway is analyzed and calculated, and the calculation result is the judgment mode of the combustion state.

[0069] Fireway temperature distribution uniformity θ h <15% when the fireway forms diffuse combustion, at this time the fireway temperature distribution uniformity is good, the NO x emission is greatly reduced; when the fireway temperature distribution uniformity θ h >15%, the fireway combustion process is in a diffusion combustion control state, at this time the NO x emission is greatly increased.

[0070] Third sequence control: adjust the flue gas double depletion control module according to the fireway temperature distribution uniformity, when the fireway temperature distribution uniformity θ h >15%, increase the frequency of the induced draft fan to increase the recirculated flue gas flow, and then the recirculated flue gas passes through the regulating valve (first flow regulating valve and second flow regulating valve) to be premixed with coke oven gas and air in a certain proportion, and after being uniformly mixed, it enters the coke oven combustion chamber to participate in the combustion reaction. When the fireway temperature distribution uniformity θ h <15%, the emission is greatly reduced.

[0071] Fourth sequence control: according to the fireway temperature distribution uniformity obtained by the third sequence control, the coke oven gas and air flow is controlled online in real time, and the fuel flow is adjusted by the regulating valve (third flow regulating valve) and flow meter (third flow regulating valve). The air flow can be adjusted in real time by adjusting the damper opening. With the increase of the recirculated flue gas flow under the third sequence control, the coke oven gas and air are heated to different degrees, and at the same time the coke oven gas and air are diluted by the flue gas, and the combustible components and oxygen concentration are reduced to different degrees. Therefore, the chemical reaction rate in the combustion process is reduced, so that the combustion process is transformed from a diffusion combustion state to a diffusion combustion state. At this time, due to the increase of the combustion reaction zone and the heat energy of the recirculated flue gas, the coke oven gas consumption is reduced, and the first, second and third sequence controls can be adjusted again to achieve the effect of energy saving.

[0072] Fifth control sequence: real-time online detection of flue gas components in the flue, mainly O2, CO and NO xThe emissions are monitored. O2 concentration monitoring is a crucial indicator for determining whether excess air in the combustion chamber dilutes the flue gas concentration, and it's also an important basis for concentration conversion. CO emission monitoring effectively determines whether combustion is complete in the coke oven combustion chamber, preventing excessive recirculated flue gas flow that leads to incomplete combustion, energy waste, and environmental pollution. When CO < 100 ppm, it indicates that the combustion reaction is basically complete; when CO ≥ 100 ppm, it indicates incomplete combustion, at which point the data terminal adjusts according to the third control sequence. NOx emission monitoring can also determine the combustion state from another perspective. When NO... x When NO <100ppm, the combustion process is under diffuse combustion control, and the coke oven combustion chamber achieves ultra-low NO. x Emissions; when NO x When the concentration is ≥100ppm, the combustion process is in diffusion combustion control state. At this time, the data terminal re-enters the second control sequence based on the result and performs adjustments accordingly.

[0073] In the coke oven combustion chamber, compared to existing conventional diffusion combustion methods, the dispersion combustion process under the dual-depletion control of flue gas in this invention has a more uniform temperature distribution, achieving NO reduction. x Ultra-low emissions (less than 100 ppm).

[0074] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0075] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the system and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A coke oven flue gas denitrification system, characterized in that, include: A data terminal, and a coke cake temperature analysis module, a flue gas double-leaning control module, a gas flow control module, and a combustion chamber temperature detection module connected to the data terminal; The coke cake temperature analysis module is used to determine the uniformity of coke cake temperature distribution; The flue gas dual-lean control module includes an induced draft fan, which is used to draw out a portion of the flue gas from the branch flue. The gas flow control module includes a first premixing chamber, a second premixing chamber, a first flow regulating valve, and a second flow regulating valve. The first inlet of the first premixing chamber is connected to the outlet of the induced draft fan through the first flow regulating valve. The first inlet of the second premixing chamber is connected to the outlet of the induced draft fan through the second flow regulating valve. The second inlet of the first premixing chamber is used to input air, and the second inlet of the second premixing chamber is used to input coke oven gas. The outlets of the first premixing chamber and the second premixing chamber are both connected to the combustion chamber. The combustion chamber temperature detection module is used to detect the uniformity of the fire channel temperature distribution in the combustion chamber; The data terminal is used to adjust the uniformity of coke cake temperature distribution when the uniformity of coke cake temperature distribution exceeds a first preset range, and to adjust the uniformity of fire channel temperature distribution by adjusting the frequency of the induced draft fan, the opening of the first flow regulating valve, and the opening of the second flow regulating valve when the uniformity of fire channel temperature distribution in the combustion chamber exceeds a second preset range. The outlet of the second premixing chamber is connected to a third flow regulating valve; The data terminal includes a coke cake temperature distribution uniformity adjustment unit. The coke cake temperature distribution uniformity adjustment unit is used to reduce the opening of the third flow regulating valve or increase the frequency of the induced draft fan when the deviation of the coke cake temperature distribution uniformity from the target coke maturity model exceeds a first preset range, until the deviation of the coke cake temperature distribution uniformity from the target coke maturity model meets the first preset range. The temperature of the coke cake is measured online in real time, and the temperature value at each point is fed back to the data terminal. The temperature at each coke cake point should first meet the target coke maturity model. If the temperature at each coke cake point does not meet this condition, it is directly fed back to the data terminal for debugging. When the target coke maturity model is met, the temperature distribution uniformity of the coke cake is analyzed and calculated.

2. The coke oven flue gas denitrification system according to claim 1, characterized in that, The coke cake temperature analysis module includes a coke cake temperature uniformity analysis unit and coke cake temperature detection probes located at various points on the coke cake; the temperature signals detected by the coke cake temperature detection probes are sent to the coke cake temperature uniformity analysis unit, and the coke cake temperature uniformity analysis unit calculates the uniformity of coke cake temperature distribution based on the received temperature signals.

3. The coke oven flue gas denitrification system according to claim 2, characterized in that, The formula for calculating the uniformity of temperature distribution in the coke cake is as follows: Where, θ c T represents the uniformity of temperature distribution in the coke cake. i,j T represents the temperature at the i-th scorch point. m,j This indicates the average temperature of the burnt cake.

4. The coke oven flue gas denitrification system according to claim 1, characterized in that, The coke cake temperature distribution uniformity adjustment unit is used to reduce the opening of the third flow regulating valve or increase the frequency of the induced draft fan when the coke cake temperature distribution uniformity deviates from the target coke maturity model by more than 5%, until the coke cake temperature distribution uniformity deviates from the target coke maturity model by less than 5%.

5. The coke oven flue gas denitrification system according to claim 1, characterized in that, The formula for calculating the uniformity of temperature distribution in the fire channel is: Where, θ h T represents the uniformity of temperature distribution in the fire channel. k T represents the temperature at the k-th fire channel measurement point. ave This indicates the average temperature of the flue.

6. The coke oven flue gas denitrification system according to claim 1, characterized in that, The data terminal includes a flue temperature distribution uniformity adjustment unit. When the flue temperature distribution uniformity is greater than 15%, the flue temperature distribution uniformity adjustment unit increases the frequency of the induced draft fan and adjusts the opening of the first flow regulating valve and the second flow regulating valve so that the flue gas passing through the first flow regulating valve and the second flow regulating valve is in a set ratio until the flue temperature distribution uniformity is less than 15%.

7. The coke oven flue gas denitrification system according to claim 1, characterized in that, A first flow meter is installed between the first flow regulating valve and the first inlet of the first premixing chamber, and a second flow meter is installed between the second flow regulating valve and the first inlet of the second premixing chamber.

8. The coke oven flue gas denitrification system according to claim 1, characterized in that, It also includes a flue gas analysis module for detecting the carbon monoxide concentration and nitrogen oxide concentration in the flue gas duct, and sending the detected carbon monoxide concentration and nitrogen oxide concentration to the data terminal; The data terminal is also used to increase the frequency of the induced draft fan and adjust the opening of the first flow regulating valve and the second flow regulating valve when the carbon monoxide concentration is greater than the first set value or the nitrogen oxide concentration is greater than the second set value, so that the flue gas passing through the first flow regulating valve and the second flow regulating valve is in a set ratio until the carbon monoxide concentration is less than the first set value and the nitrogen oxide concentration is less than the second set value.

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