Online calculation method for real-time nitrogen oxide emission concentration of boiler unit, and method for maintaining normal operation of environmental protection facilities of boiler unit

Abstract

The present disclosure relates to an online calculation method for the real-time nitrogen oxide emission concentration of a boiler unit, and a method for maintaining the normal operation of a boiler unit. In the online calculation method, the real-time nitrogen oxide emission concentration of a boiler unit in a normal working-condition state or a special working-condition state is calculated by means of a formula, and thus factors impacting the normal operation of the boiler unit can be quantified, and the impact of each factor on the boiler unit can be clearly displayed, thereby guiding workers to adjust the boiler unit. Moreover, a computer control module and a deviation determination module are used to determine whether there is a deviation in the real-time nitrogen oxide emission concentration, and perform deviation processing when there is a deviation, such that when there is a deviation in the real-time nitrogen oxide emission concentration of a boiler unit, the cause of the deviation can be quickly indicated, thereby ensuring the economic efficiency in the operation of environmental protection facilities of the boiler unit while preventing an excessive pollutant emission concentration of the boiler unit.

Description

Methods for online calculation of real-time nitrogen oxide emission concentrations of boiler units and methods for maintaining the normal operation of environmental protection facilities of boiler units. Technical Field

[0001] This disclosure relates to the field of flue gas emissions from boiler units, specifically to a method for calculating the real-time nitrogen oxide emission concentration of a boiler unit online and a method for maintaining the normal operation of environmental protection facilities for the boiler unit. Background Technology

[0002] During operation, the real-time nitrogen oxide emission concentration of existing power plant boiler units will vary depending on operating conditions, cumulative operating time, environmental parameters, and the status of environmental protection facilities. Factors affecting the real-time nitrogen oxide emission concentration of boiler units include the total environmental discharge permit amount, annual load dispatch curve, coal quality parameters, reaction temperature, reaction time, catalyst performance, and NH3 / NO3 ratio. X Molar ratio, flue gas oxygen content, cumulative operating time, and equipment health status, etc.

[0003] Currently, there is no accurate and reliable method for calculating the real-time nitrogen oxide emission concentration in boiler flue gas. When the real-time nitrogen oxide emission concentration of a boiler unit is abnormal, the boiler unit staff cannot quickly find the cause of the abnormality. Relying on experience to adjust parameters or shut down the boiler for maintenance not only leads to excessive emissions but also affects the economic efficiency of the boiler unit.

[0004] Summary of the Invention

[0005] The purpose of this disclosure is to provide a method for calculating the real-time nitrogen oxide emission concentration of a boiler unit online and a method for maintaining the normal operation of the boiler unit's environmental protection facilities, so as to solve the problems in the prior art that there is no accurate and reliable method for calculating the real-time nitrogen oxide emission concentration of a boiler unit, the inability to quickly find the cause of abnormal real-time nitrogen oxide emission concentration, and the inability to deal with the problem in a timely manner.

[0006] To achieve the above objectives, the first aspect of this disclosure provides a method for online calculation of real-time nitrogen oxide emission concentration of a boiler unit, the method comprising:

[0007] S1. Determine the current operating condition of the boiler unit based on its continuous operating time T; when the continuous operating time T of the boiler unit is less than 2000h, the operating condition is a normal operating condition; when the continuous operating time T of the boiler unit is greater than 2000h, the operating condition is a special operating condition.

[0008] S2. Calculate the real-time nitrogen oxide emission concentration V0 of the boiler unit based on the operating conditions of the boiler unit;

[0009] When the boiler unit is under normal operating conditions, the real-time nitrogen oxide emission concentration V0 of the boiler unit is calculated using Equation 1, with the unit being mg / Nm³. 3 V0 = 35 - KTΦ, Equation 1;

[0010] When the boiler unit is under the special operating condition, the real-time nitrogen oxide emission concentration V0 of the boiler unit is calculated using Equation 2, with the unit being mg / Nm3: V0=35-[KTΦ+(k1V1+k2V2+k3V3+k4V4+k5V5+k6V6)], Equation 2;

[0011] In the formula: K refers to the calculation correction coefficient of the boiler unit, which is dimensionless; T refers to the continuous operating time of the boiler unit, in hours; Φ refers to the performance degradation value of the boiler unit catalyst, in mg / Nm³. 3 .H; V1 refers to the contribution value of the reaction temperature of the catalyst in the boiler unit to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm³. 3 k1 refers to the calculation correction coefficient for the catalyst reaction temperature of the boiler unit, which is dimensionless; V2 refers to the contribution value of the combustion and coal quality changes of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm³. 3 k2 refers to the calculation correction coefficient for boiler combustion and coal quality changes of the boiler unit, which is dimensionless; V3 refers to the contribution value of the denitrification reaction time of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, with the unit being mg / Nm³. 3 k3 refers to the calculation correction coefficient for the denitrification differential pressure and time of the boiler unit, which is dimensionless; V4 refers to the contribution value of the effective reaction volume of the catalyst of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm³. 3 k4 refers to the calculation correction factor for the effective volume of the catalyst in the boiler unit, which is dimensionless; V5 refers to the contribution value of the ammonia-nitrogen molar ratio of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm³. 3 k5 refers to the calculation correction coefficient for the ammonia-nitrogen molar ratio of the boiler unit, which is dimensionless; V6 refers to the contribution value of the total nitrogen oxide emission constraint of the entire plant units to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm³. 3 k6 refers to the calculation correction coefficient for the total nitrogen oxide emission control of the boiler unit, which is dimensionless.

[0012] Optionally, the performance degradation parameter Φ and the calculation correction coefficient K are obtained based on the continuous operating time T of the boiler unit.

[0013] Optionally, the influence contribution value V1 is calculated using Equation 3: V1 = (V 线 -V 保 )×(1-T1 / T0), Equation 3;

[0014] In the formula: V 线 This refers to the online measured concentration of nitrogen oxides in the boiler unit, expressed in mg / Nm³. 3 V 保 This refers to the factory-guaranteed nitrogen oxide concentration performance value of the boiler unit, in mg / Nm³. 3 T1 refers to the real-time reaction temperature of the denitrification device in the boiler unit, in °C; T0 refers to the optimal reaction temperature of the denitrification device in the boiler unit.

[0015] The unit is ℃; the calculation correction factor k1 is obtained based on the reaction temperature of the catalyst in the boiler unit.

[0016] Optionally, the influence contribution value V2 is calculated using Equation 4:

[0017] Where: N ar实 This refers to the nitrogen content in the actual coal used in the boiler unit, expressed as a percentage by weight (N). ar设 This refers to the nitrogen content in the coal used in the design of the boiler unit, expressed as a percentage by weight (%). 实 This refers to the flame center temperature during pulverized coal combustion in the boiler unit, expressed in °C; T 燃烧 α refers to the theoretical flame center temperature during pulverized coal combustion in the boiler unit furnace, in °C; α refers to the oxygen content in the air during pulverized coal combustion in the boiler unit furnace, in volume %; the calculation correction coefficient k2 is obtained based on the coal type variation parameters, combustion temperature variation parameters, and air oxygen content α.

[0018] Optionally, the influence contribution value V3 is calculated using Equation 5:

[0019] In the formula: P1 refers to the actual differential pressure of the catalyst in the boiler unit, in kPa; P0 refers to the theoretical differential pressure of the catalyst in the boiler unit, in kPa; η1 refers to the actual denitrification efficiency of the boiler unit, in %; η2 refers to the reaction time t between the flue gas and ammonia mixture and the catalyst in the boiler unit. i The corresponding denitrification efficiency is expressed in %; the calculation correction coefficient k3 is based on the catalyst differential pressure of the boiler unit and the contact time t between the catalyst and the flue gas. i get;

[0020] The contact time t between the catalyst and the flue gas i The result is obtained by calculating t using Equation 6.i =V / Q, Equation 6;

[0021] In the formula: Q refers to the actual amount of flue gas flowing through the catalyst in the boiler unit, in m³. 3 / s; V refers to the hollow volume of the catalyst channel of the boiler unit, in meters. 3 ;t i This refers to the time it takes for the flue gas and ammonia mixture to pass through the catalyst channel in the boiler unit, measured in seconds.

[0022] Optionally, the impact contribution value V4 is calculated using Equation 7: V4 = (V 线 -V 保 )×(M'1 / M1+M'2 / M2+M'3 / M3), Equation 7;

[0023] In the formula: M'1 refers to the effective volume loss of the first layer of catalyst in the boiler unit, in m³. 3 M1 refers to the effective volume of the first layer of catalyst in the boiler unit when it is brand new, in cubic meters. 3 M'2 refers to the effective volume loss of the second layer catalyst in the boiler unit, in m³. 3 M2 refers to the effective volume of the second layer catalyst of the boiler unit when it is brand new, in cubic meters. 3 M'3 refers to the effective volume loss of the third layer catalyst in the boiler unit, in m³. 3 M3 refers to the effective volume of the third layer catalyst of the boiler unit when it is brand new, in cubic meters. 3 The correction factor k4 is calculated based on the total effective volume loss ratio of the three-layer catalyst.

[0024] Optionally, the contribution value of V5 is calculated using Equation 8: V5 = (V 线 -V 保 )×(1-Q1 / Q0)×(1-η1 / η 设 Equation 8;

[0025] In the formula: Q1 refers to the actual ammonia injection rate of the denitrification device in the boiler unit, m 3 / s; Q0 refers to the theoretical ammonia injection rate of the denitrification unit in the boiler unit, m 3 / s; η1 refers to the actual denitrification efficiency of the boiler unit, in %; η 设 This refers to the design denitrification efficiency of the boiler unit, expressed in %; the calculation correction coefficient k5 is obtained based on the ammonia injection rate of the boiler unit.

[0026] Optionally, the contribution value of V6 is calculated using Equation 9: V6 = (V 线 -V 保 )×(1-Q剩 / Q 总 Equation 9;

[0027] In the formula: Q 剩 This refers to the remaining amount of nitrogen oxide emissions from the boiler unit, expressed in tons per year (t / a); Q 总 This refers to the total nitrogen oxide emission distribution Q of the boiler unit. 总 The unit is t / a; the calculation correction factor k6 is obtained based on the nitrogen oxide emissions of the boiler unit;

[0028] The remaining nitrogen oxide emission allocation Q of the boiler unit is calculated using Equation 10. 剩 Q 剩 =Q 总 -Q y Formula 10;

[0029] In the formula, Q y This refers to the allocated usage of nitrogen oxide emissions from the boiler unit; based on the remaining nitrogen oxide emissions Q allocated from the boiler unit. 剩 The total nitrogen oxide emissions Q of the boiler unit 总 The ratio is used to obtain the calculated correction coefficient k6.

[0030] A second aspect of this disclosure provides a method for maintaining the normal operation of environmental protection facilities in a boiler unit, the method comprising:

[0031] S3. The computer control module obtains the real-time nitrogen oxide emission concentration V0 according to the calculation method described in the first aspect, and the real-time nitrogen oxide emission concentration V0 is subjected to deviation judgment by the deviation judgment module. When the real-time nitrogen oxide emission concentration V0 is outside the control range, the deviation judgment module issues an alarm signal; the control range is 10-50 mg / Nm³. 3 ;

[0032] S4. When the deviation processing module receives the alarm signal issued by the deviation judgment module, the computer control module performs deviation processing.

[0033] Optionally, the deviation processing includes: having the computer control module compare the absolute values ​​of the influence levels k1V1, k2V2, k3V3, k4V4, k5V5, and k6V6, and assigning the influence levels in descending order of absolute value as the first processing item, the second processing item, the third processing item, the fourth processing item, the fifth processing item, and the sixth processing item; when the influence level k6V6 is the first processing item, having the computer control module allocate the total amount Q of nitrogen oxide emissions from the temporary nitrogen oxide emissions. 临机总 Adjustments will be made until the alarm signal is cleared; when the total nitrogen oxide emissions Q are allocated... 临机总If the allocation threshold is not met, the computer control module will disable the value of k6V6 and continue to calculate according to Equation 2; or, the control mode of the boiler unit will be switched to manual control.

[0034] The above technical solution categorizes the boiler unit's operating status into normal and special operating conditions based on its continuous operating time T. By calculating the real-time nitrogen oxide emission concentration under either normal or special operating conditions using formulas, the factors affecting the boiler unit's normal operation can be quantified, clearly displaying the impact of each factor on the boiler unit and guiding operators in adjusting it. Furthermore, the computer control module and deviation judgment module determine whether there are deviations in the real-time nitrogen oxide emission concentration and handle these deviations accordingly. This allows for rapid indication of the cause of deviations when they occur, thus ensuring the boiler unit's economic efficiency while preventing excessive pollutant emissions. Attached Figure Description

[0035] Figure 1 is a flowchart of a method for maintaining the normal operation of environmental protection facilities of a boiler unit according to the present disclosure. Detailed Implementation

[0036] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0037] The first aspect of this disclosure provides a method for calculating the real-time nitrogen oxide emission concentration of a boiler unit, the method comprising:

[0038] S1. Determine the current operating condition of the boiler unit based on its continuous operating time T; when the continuous operating time T of the boiler unit is less than 2000h, the operating condition is a normal operating condition; when the continuous operating time T of the boiler unit is greater than 2000h, the operating condition is a special operating condition.

[0039] S2. Calculate the real-time nitrogen oxide emission concentration V0 of the boiler unit based on the operating conditions of the boiler unit;

[0040] When the boiler unit is under normal operating conditions, the real-time nitrogen oxide emission concentration V0 of the boiler unit is calculated using Equation 1, with the unit being mg / Nm³. 3 V0 = 35 - KTΦ, Equation 1;

[0041] When the boiler unit is under the aforementioned special operating condition, the real-time nitrogen oxide emission concentration V0 of the boiler unit is calculated using Equation 2, with the unit being mg / Nm³.3 V0 = 35 - [KTΦ + (k1V1 + k2V2 + k3V3 + k4V4 + k5V5 + k6V6)], Equation 2;

[0042] In the formula: K refers to the calculation correction coefficient of the boiler unit, which is dimensionless; T refers to the continuous operating time of the boiler unit, in hours; Φ refers to the performance degradation value of the boiler unit catalyst, in mg / Nm³. 3 .H; V1 refers to the contribution value of the reaction temperature of the catalyst in the boiler unit to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm³. 3 k1 refers to the calculation correction coefficient for the catalyst reaction temperature of the boiler unit, which is dimensionless; V2 refers to the contribution value of the combustion and coal quality changes of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm³. 3 k2 refers to the calculation correction coefficient for boiler combustion and coal quality changes of the boiler unit, which is dimensionless; V3 refers to the contribution value of the denitrification reaction time of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, with the unit being mg / Nm³. 3 k3 refers to the calculation correction coefficient for the denitrification differential pressure and time of the boiler unit, which is dimensionless; V4 refers to the contribution value of the effective reaction volume of the catalyst of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm³. 3 k4 refers to the calculation correction factor for the effective volume of the catalyst in the boiler unit, which is dimensionless; V5 refers to the contribution value of the ammonia-nitrogen molar ratio of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm³. 3 k5 refers to the calculation correction coefficient for the ammonia-nitrogen molar ratio of the boiler unit, which is dimensionless; V6 refers to the contribution value of the total nitrogen oxide emission constraint of the entire plant units to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm³. 3 k6 refers to the calculation correction coefficient for the total nitrogen oxide emission control of the boiler unit, which is dimensionless.

[0043] Through the above implementation methods, the operating status of the boiler unit is divided into normal operating condition and special operating condition based on the continuous operating time T. The real-time nitrogen oxide emission concentration of the boiler unit under normal or special operating conditions is calculated using formulas, quantifying the factors affecting the normal operation of the boiler unit and clearly displaying the impact of each factor on the boiler unit. This guides the operators in adjusting the boiler unit. Furthermore, the computer control module and deviation judgment module determine whether there is a deviation in the real-time nitrogen oxide emission concentration and handle the deviation if one occurs. This allows for rapid indication of the cause of the deviation when it occurs, thus ensuring the economic efficiency of the boiler unit operation while preventing excessive pollutant emissions.

[0044] In one embodiment, when the continuous operating time of the boiler unit is less than 2000 hours, the conditions of the denitrification reaction, boiler combustion, operating conditions of the denitrification device, the properties of the catalyst, and the operating conditions of the ammonia injection device have a relatively small impact on the real-time nitrogen oxide emission concentration V0 of the boiler unit. Therefore, the influence of each influencing factor on the real-time nitrogen oxide emission concentration can be disregarded. In this case, Equation 2 can be simplified to Equation 1, that is, the real-time nitrogen oxide emission concentration V0 of the boiler unit under normal operating conditions can be calculated using Equation 1. When the continuous operating time of the boiler unit is greater than 2000 hours, one or more of the conditions of the denitrification reaction, boiler combustion, operating conditions of the denitrification device, the properties of the catalyst, and the operating conditions of the ammonia injection device will affect the real-time nitrogen oxide emission concentration V0 of the boiler unit. Equation 2 cannot be simplified. Therefore, the real-time nitrogen oxide emission concentration V0 of the boiler unit under special operating conditions can be calculated using Equation 2. The magnitude of the impact can be represented by the product of the corresponding impact contribution value and the calculated correction coefficient (k1V1, k2V2, k3V3, k4V4, k5V5 and k6V6).

[0045] In one embodiment, the value 35 in Formulas 1 and 2 refers to the ultra-low emission limit for nitrogen oxides of the boiler unit, with units of mg / Nm³. 3 Among them, the ultra-low emission limits for nitrogen oxides from coal-fired power units are based on the upper limit of the standards implemented by laws and regulations (NOx). X ≤100mg / Nm 3 ), the upper limit of ultra-low emission control standards (NO) X ≤50mg / Nm 3 ) and the upper limit of environmental assessment implementation standards (NO) X ≤35mg / Nm 3 This was obtained after evaluation.

[0046] In a preferred embodiment, the enterprise standard limit for real-time nitrogen oxide emission concentration is 10 ≤ NO X ≤35mg / Nm 3 In this embodiment, the enterprise standard is obtained by each plant based on the relevant parameters of the boiler unit and the assessment of the ultra-low emission limits for nitrogen oxides of the boiler unit. The ultra-low emission limit for nitrogen oxides of coal-fired units can be adjusted and set to 35-Δ, where Δ is the safety margin for unit adjustment. Δ can be set to 0-25, preferably 1-10, and the unit is mg / Nm³. 3 Among the relevant parameters for boiler units from various manufacturers are: upper and lower limits of ammonia slip rate (upper limit: 2.5 mg / Nm³). 3 The parameters include: no lower limit, upper and lower limits of denitrification efficiency (upper limit 95%, lower limit 40%), upper and lower limits of denitrification reaction temperature (upper limit 420℃, lower limit 250℃), minimum continuous denitrification operating temperature (290℃), normal catalyst reaction time (200 milliseconds), and lower limit of catalyst reaction time (50 milliseconds).

[0047] In one embodiment, after the boiler unit is put into operation, it will exhibit a gradual performance degradation phenomenon. The performance degradation parameter Φ and the calculation correction coefficient K can be obtained based on the continuous operating time of the boiler unit. Specifically, the performance degradation value Φ of the boiler unit described in this disclosure can be a value in the range of 0.0001 to 0.0009, for example, Φ can be 0.0001, 0.0002, 0.0003, 0.0004, 0.0005, 0.0006, 0.0007, 0.0008, and 0.0009. The boiler unit used in this disclosure is a conventional boiler unit in the art; for example, the boiler unit includes a combustion device and a denitrification reaction device. The calculation correction factor K of the boiler unit described in this disclosure can be a value in the range of 0.800 to 2.000. For example, the calculation correction factor K can be 0.800, 0.850, 0.900, 0.950, 1.000, 1.100, 1.300, 1.500 and 2.000.

[0048] In one specific implementation, the values ​​of the performance degradation parameter Φ and the calculated correction coefficient K can be obtained from the relationship table (Table 1) between the calculated correction coefficient K and the performance degradation parameter Φ and the continuous operating time T of the boiler unit.

[0049] In one embodiment, the combustion device of the boiler unit is a conventional choice in the art, and this disclosure does not make any special requirements. For example, the combustion device is a low-NOx burner. The upper and lower limits of NOx emission from this low-NOx burner are given by the boiler manufacturer. The upper limit of NOx emission from the low-NOx burner used in this disclosure is NO X ≤300mg / Nm 3 The lower limit for pollution generation is NO.X ≤50mg / Nm 3 .

[0050] In this embodiment, the boiler material is burned in the combustion device, and the resulting flue gas contains NO. X NO X It is mainly composed of NO and NO2, with NO accounting for more than 90% by volume. NH3 and flue gas from combustion devices enter the denitrification reactor and come into contact with the catalyst to undergo a denitrification reaction, selectively removing NO from the flue gas. X It is reduced to non-toxic and pollution-free N2 and H2O. When the temperature of the denitrification reaction is 300-350℃, the following reactions occur in the denitrification unit: 4NH3 + 4NO + O2 = 4N2 + 6H2O or 4NH3 + 2NO + O2 = 3N2 + 6H2O; when the temperature of the denitrification reaction is below 300℃, the following reactions occur in the denitrification unit: 4NH3 + 3O2 = 2N2 + 6H2O + 1267.1KJ; when the temperature of the denitrification reaction is above 350℃, the following reactions occur in the denitrification unit: 2NH3 = N2 + 3H2 - 91.9KJ or 4NH3 + 5O2 = 4NO + 6H2O + 907.3KJ. The kinetic principle of the denitrification reaction mainly includes: NO X NH3 and O2 diffuse from the flue gas to the outer surface of the catalyst; NO X NH3 and O2 further diffuse into the microporous surface of the catalyst; gaseous NO X O2 reacts with NH3 adsorbed on the active sites of the catalyst surface to generate N2 and H2O; N2 and H2O desorb from the catalyst surface into the micropores; the desorbed N2 and H2O diffuse from the catalyst surface into the main flue gas stream and are carried away.

[0051] In one embodiment, the catalyst used in the denitrification device of the boiler unit disclosed herein needs to be flexibly selected according to the properties of the flue gas generated by the boiler unit. For example, the catalyst can be a V2O5 / TiO2 vanadium-based catalyst.

[0052] In one embodiment, the influence contribution value V1 and the calculation correction coefficient k1 are related to the denitrification reaction temperature of the catalyst in the denitrification device, wherein the influence contribution value V1 is calculated using Equation 3: V1=(V 线 -V 保 )×(1-T1 / T0), Equation 3;

[0053] In the formula: V 线 This refers to the online measured concentration of nitrogen oxides in the boiler unit, expressed in mg / Nm³. 3 V 保 This refers to the factory-guaranteed nitrogen oxide concentration performance value of the boiler unit, in mg / Nm³. 3T1 refers to the real-time reaction temperature of the denitrification device of the boiler unit, in °C; T0 refers to the optimal reaction temperature of the denitrification device of the boiler unit, in °C.

[0054] In one embodiment, the calculation correction coefficient k1 can be obtained from the relationship table (Table 2) between the denitrification reaction temperature of the catalyst of the boiler unit and the calculation correction coefficient k1.

[0055] In one embodiment, the influence contribution value V2 and the calculation correction coefficient k2 are related to changes in coal type, combustion temperature, and air oxygen content α. The influence contribution value V2 is calculated using Equation 4:

[0056] Where: N ar实 This refers to the nitrogen content in the actual coal used in the boiler unit, expressed as a percentage by weight (N). ar设 This refers to the nitrogen content in the coal used in the design of the boiler unit, expressed as a percentage by weight (%). 实 This refers to the flame center temperature during pulverized coal combustion in the boiler unit, expressed in °C; T 燃烧 α refers to the theoretical flame center temperature during pulverized coal combustion in the boiler furnace, in °C; α refers to the oxygen content of the air during pulverized coal combustion in the boiler furnace, in volume%.

[0057] In one embodiment, the change in coal type can be indicated by a coal type change parameter, which can be determined by (N) ar实 -N ar设 ) / N ar设 Quantification; changes in combustion temperature can be indicated by parameters related to combustion temperature variation, and changes in coal type can be indicated by parameters related to T. 实 -T 燃烧 Quantification; the oxygen content α in the air can be obtained by an oxygen content detection device installed in the air intake chamber.

[0058] In one embodiment, the correction factor k2 can be calculated based on the relationship table (Table 3) between boiler combustion and coal quality changes and the calculation correction factor k2.

[0059] In a preferred embodiment, the relationship between the obtained coal type variation parameters, combustion temperature variation parameters, and air oxygen content α, the boiler combustion and coal quality changes, and the calculated correction coefficient k2 are used as shown in Table 3. Specifically, the first calculated correction coefficient k2 is obtained based on the coal type variation parameters. 21 The second calculation correction coefficient k is obtained based on the combustion temperature change parameter. 22 The third calculation correction factor k is obtained based on the air oxygen content α. 23 By comparing the first calculation, the correction factor k is calculated. 21Second, calculate the correction factor k. 22 And the third calculation correction factor k 23 The value of the three is the largest among them, and the calculation correction coefficient is the calculation correction coefficient k2.

[0060] In one embodiment, if changes in the nitrogen content of coal cannot be detected online or the combustion temperature cannot be measured, Equation 4 can be substituted to obtain Equation 4-1. The influence contribution value V2 can be obtained through Equation 4-1: V2=(V 线 -V 保 )×(1-V 线 / V 保 +▲), Equation 4-1;

[0061] In the formula: ▲ refers to the compensation value for changes in the combustion state and coal type of the boiler unit, with the unit being mg / Nm³. 3 The compensation value can be calculated based on the coal combustion and combustion characteristics of the boiler unit as described in Table 3, and by setting fixed compensation values ​​for different states according to the online monitoring temperature at the furnace outlet and the amount of coal consumed by the unit.

[0062] In one embodiment, the influence contribution value V3 and the calculated correction coefficient k3 are related to the catalyst differential pressure of the denitrification reaction and the contact time t between the catalyst and the flue gas. i In this embodiment, the concentration of nitrogen oxides in the flue gas obtained after treatment by the denitrification device is related to the reaction time of the denitrification reaction. In this embodiment, ammonia gas injected from the ammonia injection device of the denitrification device and flue gas are brought into contact in the denitrification device to test the effect of time, resulting in a denitrification time-efficiency relationship graph. This graph shows that the denitrification efficiency increases with increasing contact time, reaching its maximum when the contact time reaches 200 milliseconds, after which the denitrification efficiency decreases. As the contact time between NH3 gas and the catalyst gradually increases, it facilitates the diffusion, adsorption, and reaction of NH3 gas within the catalyst pores, as well as the desorption and diffusion of the product gas, thereby improving the denitrification efficiency. If the contact time is too long, NH3 gas undergoes an oxidation reaction, reducing the reducing medium and causing the denitrification efficiency to decrease.

[0063] In one embodiment, the influence contribution value V3 is calculated using Equation 5:

[0064] In the formula: P1 refers to the actual differential pressure of the catalyst in the boiler unit, in kPa; P0 refers to the theoretical differential pressure of the catalyst in the boiler unit, in kPa; η1 refers to the actual denitrification efficiency of the boiler unit, in %; η2 refers to the reaction time t between the flue gas and ammonia mixture and the catalyst in the boiler unit. iThe corresponding denitrification efficiency is expressed in %; the calculation correction coefficient k3 is based on the catalyst differential pressure of the boiler unit and the contact time t between the catalyst and the flue gas. i get.

[0065] In one embodiment, the catalyst differential pressure of the boiler unit can be quantified by (P1-P0) / P0, and the contact time t between the catalyst and the flue gas is... i The result is obtained by calculating t using Equation 6. i =V / Q, Equation 6;

[0066] In the formula: Q refers to the actual amount of flue gas flowing through the catalyst in the boiler unit, in m³. 3 / s; V refers to the hollow volume of the catalyst channel of the boiler unit, in meters. 3 ;t i This refers to the time it takes for the flue gas and ammonia mixture to pass through the catalyst channel in the boiler unit, measured in seconds.

[0067] In one embodiment, the correction coefficient k3 can be obtained from the table (Table 4) showing the relationship between the denitrification differential pressure and time of the boiler unit and the correction coefficient k3.

[0068] In a preferred embodiment, the catalyst differential pressure of the boiler unit and the contact time t between the catalyst and the flue gas are obtained. i Referring to the table (Table 4) showing the relationship between the denitrification differential pressure and time of the boiler unit and the calculated correction factor k3, specifically, the first calculated correction factor k is obtained based on the catalyst differential pressure. 31 According to the contact time t i The second calculation correction coefficient k is obtained. 32 By comparing the first calculation, the correction factor k is calculated. 31 Second calculation of correction coefficient k 32 The value of the three is used to calculate the correction factor k3, which is the largest among them.

[0069] The method for calculating the hollow volume V of the catalyst channel in the boiler unit is as follows: After setting the catalyst size and gas flow rate, the interfacial mass transfer coefficient can be calculated, and the NH3 concentration at the input inlet of the denitrification device is substituted into dC. A S / dA=γ N / F can be used to determine the catalyst surface area, or the NO concentration at the input inlet of the denitrification device can be substituted into dC. N B / dA=γ A / F can be used to obtain the catalyst surface area, and thus the actual size of the catalyst; where A refers to the catalyst surface area, in meters. 2 F refers to the gas phase flow rate, in meters (m). 3 / s;C NB This refers to the NO concentration at the inlet of the denitrification device, in mol / m³. 3 C A S This refers to the NH3 concentration at the inlet of the denitrification device; γ N The NO consumption rate in the denitrification reaction is expressed in mol / m³. 2 ·s; γ A The rate of NH3 consumption in the denitrification reaction is expressed in mol / m³. 2 ·s.

[0070] Among them, the concentration γ of NO at the inlet in the gas phase bulk N The concentration γ of NH3 at the inlet in the gas phase bulk was calculated using Equation 6-1. A The result is obtained by calculation using Equation 6-2:

[0071] Among them, K fN This refers to the NO interface mass transfer coefficient, in m / s; K fA It refers to the NH3 interfacial mass transfer coefficient, in m / s.

[0072] In one embodiment, the concentration of nitrogen oxides in the flue gas obtained after denitrification is related to the catalyst performance. In this embodiment, V2O5 / TiO2 vanadium-based catalysts with V2O5 contents of 1.4 wt%, 3.0 wt%, 4.5 wt%, and 6.6 wt% were prepared, and the catalysts were tested under the same conditions to obtain catalyst component efficiency relationship diagrams. Based on these diagrams, the following conclusions can be drawn: when the V2O5 content in the catalyst is between 1.4 and 4.5 wt%, the catalytic efficiency increases with increasing V2O5 content, thus improving the denitrification efficiency. When the V2O5 content exceeds 6.6 wt%, the catalytic efficiency decreases. This is mainly due to the different distribution of V2O5 on the TiO2 support. When the V2O5 content is between 1.4 and 4.5 wt%, V2O5 is uniformly distributed on the TiO2 support and exists in an equiaxed polymerized vanadium-based form. When the V2O5 content is above 6.6% by weight, new V2O5 crystallization regions are formed on the TiO2 support, thereby reducing the catalyst activity.

[0073] In this embodiment, V₂O₅ is the active component of the catalyst reaction, which, under the action of NH₃, reduces NO in the flue gas. XReduction to N2 and H2O can also oxidize SO2 in flue gas to SO3. Therefore, in industrial applications, the V2O5 content is relatively low. Adding co-catalysts WO3 or MoO3 is necessary. WO3, used in larger quantities, acts as both a "catalytic" and a "structure-regulating" aid in the catalyst, increasing the temperature range of the active reaction and improving its mechanical structure and crystal properties. Trace elements like arsenic produced in coal combustion can poison the catalyst, causing it to lose activity. MoO3 exhibits good tolerance to arsenic poisoning.

[0074] In one embodiment, the influence contribution value V4 and the calculation correction coefficient k4 are related to the effective volume loss of the catalyst in the boiler unit. In this embodiment, the boiler unit inevitably experiences volume loss and / or effective volume loss during operation. When this occurs, the denitrification reaction becomes less effective, and the corresponding nitrogen oxide emission concentration V0 of the boiler unit increases.

[0075] In one implementation, the influence contribution value V4 is calculated using Equation 7: V4 = (V 线 -V 保 )×(M'1 / M1+M'2 / M2+M'3 / M3), Equation 7;

[0076] In the formula: M'1 refers to the effective volume loss of the first layer of catalyst in the boiler unit, in m³. 3 M1 refers to the effective volume of the first layer of catalyst in the boiler unit when it is brand new, in cubic meters. 3 M'2 refers to the effective volume loss of the second layer catalyst in the boiler unit, in m³. 3 M2 refers to the effective volume of the second layer catalyst of the boiler unit when it is brand new, in cubic meters. 3 M'3 refers to the effective volume loss of the third layer catalyst in the boiler unit, in m³. 3 M3 refers to the effective volume of the third layer catalyst of the boiler unit when it is brand new, in cubic meters. 3 The correction factor k4 is calculated based on the total effective volume loss ratio of the three-layer catalyst.

[0077] In one embodiment, the catalyst in the boiler unit described in this disclosure is arranged in three stacked layers: a first catalyst layer, a second catalyst layer, and a third catalyst layer. The third catalyst layer is located downstream of the second catalyst layer, and the second catalyst layer is located downstream of the first catalyst layer. In this embodiment, the effective volume loss of each catalyst layer is related to the continuous operating time T. The effective volume loss percentages of the first, second, and third catalyst layers can be obtained from the table (Table 5) showing the relationship between the effective volume loss percentages of the three catalyst layers and the continuous operating time.

[0078] In one embodiment, the calculation correction coefficient k4 is obtained based on the total effective volume loss ratio of the three catalyst layers, wherein the total effective volume loss ratio of the three catalyst layers refers to the sum of the effective volume loss ratios of the first catalyst layer, the second catalyst layer, and the third catalyst layer. The specific value of the calculation correction coefficient k4 is obtained from the relationship table (Table 6) between the total effective volume loss ratio of the boiler unit's catalyst and the calculation correction coefficient k4.

[0079] In one embodiment, when the total effective volume loss of the three-layer catalyst reaches more than 10%, the catalyst in the boiler unit can be regenerated or shut down for repair.

[0080] In one embodiment, the influence contribution value V5 and the calculation correction coefficient k5 are related to the ammonia-nitrogen molar ratio of the boiler unit, wherein the ammonia-nitrogen molar ratio of the boiler unit is controlled by the ammonia injection status of the ammonia injection device.

[0081] In one embodiment, the influence contribution value V5 is calculated using Equation 8: V5 = (V 线 -V 保 )×(1-Q1 / Q0)×(1-η1 / η 设 Equation 8;

[0082] In the formula: Q1 refers to the actual ammonia injection rate of the denitrification device in the boiler unit, m 3 / s; Q0 refers to the theoretical ammonia injection rate of the denitrification unit in the boiler unit, m 3 / s; η1 refers to the actual denitrification efficiency of the boiler unit, in %; ηdesign refers to the designed denitrification efficiency of the boiler unit, in %.

[0083] In one embodiment, the calculation correction coefficient k5 is obtained based on the ammonia injection status of the boiler unit. The ammonia injection status can be quantified by (Q1-Q0) / Q0. When the value of (Q1-Q0) / Q0 is less than -5%, it indicates that the boiler unit is in a state of insufficient ammonia injection, and the calculation correction coefficient k5 value is relatively large, between 1.050 and 1.300. When the value of (Q1-Q0) / Q0 is between -5% and 5%, it indicates that the boiler unit is in a state of normal ammonia injection, and the calculation correction coefficient k5 value is 1.000. When the value of (Q1-Q0) / Q0 is greater than 5%, it indicates that the boiler unit is in a state of excessive ammonia injection, and the calculation correction coefficient k5 value is relatively small, specifically between 0.800 and 0.950.

[0084] In one specific implementation, the specific value of the calculation correction coefficient k5 is obtained from the relationship table (Table 7) between the ammonia-nitrogen molar ratio of the boiler unit and the calculation correction coefficient k5.

[0085] In one embodiment, the boiler unit schedules its annual shutdown and maintenance plan in advance before the start of the year's operation, and sets the shutdown time T. 检 Set to 168 hours or more. During the year-round operation of the boiler unit, there may be situations where the unit needs to be shut down for maintenance due to accidents. The downtime for such shutdowns is T. 事 In addition, the actual continuous operating time T of the boiler unit throughout the year. 实际 =8762-T 事 -T 检 .

[0086] In one specific embodiment, the boiler unit includes Unit 1 and Unit 2, with Unit 1 having a continuous operating time of T1 and Unit 2 having a continuous operating time of T2. Then, the power generation utilization hours T of Unit 1 are obtained based on the continuous operating times T1 and T2, respectively. 1运 and the number of generating hours T of Unit 2 2运 In this embodiment, the power generation utilization hours T of Unit 1 1运 and the number of generating hours T of Unit 2 2运 This refers to the full-load operating time of the generator unit within one year. If either Unit 1 or Unit 2 operates at full load for the entire one-year period, then the continuous operating time of Unit 1 is T1, which is the number of power generation utilization hours T. 1运 The continuous operating time of Unit 2 is T2, which is the number of power generation utilization hours T. 2运 When Unit 1 or Unit 2 operates at a non-full load during a one-year period, the average power of Unit 1 or Unit 2 during the one-year operating period is calculated using historical power variation statistics. Then, the power generation utilization hours T of the boiler unit are obtained by multiplying the continuous operating time T1 of Unit 1 by the average power. 1运 The power generation utilization hours T of the boiler unit are obtained by multiplying the continuous operating time T2 of Unit 2 by the average power. 2运 .

[0087] In one implementation, the total nitrogen oxide emission allocation Q of the boiler unit is determined based on the total nitrogen oxide emissions of the entire plant as issued by the Ecological Environment Bureau through the discharge permit. 总 The total nitrogen oxide emission distribution Q1 and Q2 for Unit 1 and Unit 2 are calculated using Equations 10-1 and 10-2, respectively. Equations 10-1 and 10-2 are as follows:

[0088] In one embodiment, as the operating time of the boiler unit gradually increases, the nitrogen oxide emissions of the boiler unit gradually increase, that is, the nitrogen oxide emission allocation Q of the boiler unit... y The amount of nitrogen oxide emissions allocated and used is gradually increasing, among which the amount of nitrogen oxide emissions allocated and used is Q. y Q is obtained by calculation using Equation 10-3. y =Q 烟气 ×V 排放 ×η 脱硝 Equation 10-3;

[0089] In the formula, Q 烟气 V refers to the total flue gas emissions of the boiler unit. 排放 This refers to the measured average concentration of nitrogen oxides in the boiler unit, η. 脱硝 This refers to the average denitrification efficiency of the boiler unit.

[0090] In one specific implementation, the nitrogen oxide emission allocation for Unit 1 is calculated using Equation 10-4, and the nitrogen oxide emission allocation for Unit 2 is calculated using Equation 10-5: Q 1y =Q 烟气1 ×V 排放1 ×η 脱硝1 Equation 10-4; Q 2y =Q 烟气2 ×V 排放2 ×η 脱硝2 Equation 10-5;

[0091] In the formula, Q 烟气1 This refers to the total flue gas emissions of Unit 1, V 排放1 This refers to the measured average concentration of nitrogen oxides in Unit 1, η. 脱硝1 This refers to the average denitrification efficiency of Unit 1; Q 烟气2 This refers to the total flue gas emissions of Unit 2, V 排放2 This refers to the measured average concentration of nitrogen oxides in Unit 2, η. 脱硝2 This refers to the average denitrification efficiency of Unit 2.

[0092] In one embodiment, the influence contribution value V6 and the calculation correction coefficient k6 are related to the residual amount Q of nitrogen oxide emissions from the boiler unit. 剩 Regarding this, the contribution value V6 is calculated using Equation 9: V6=(V 线 -V 保 )×(1-Q 剩 / Q 总 Equation 9;

[0093] In the formula: Q 剩This refers to the remaining amount of nitrogen oxide emissions from the boiler unit, expressed in tons per year (t / a); Q 总 This refers to the total nitrogen oxide emission distribution Q of the boiler unit. 总 The unit is t / a.

[0094] In one embodiment, the residual amount Q of nitrogen oxide emissions from the boiler unit is allocated. 剩 Q is obtained by calculation using Equation 10. 剩 =Q 总 -Q y Formula 10;

[0095] In the formula, Q y This refers to the allocation and usage of nitrogen oxide emissions from the boiler unit.

[0096] In one embodiment, the remaining amount Q is allocated based on the nitrogen oxide emissions of the boiler unit. 剩 The total nitrogen oxide emissions Q of the boiler unit 总 The ratio is used to obtain the calculation correction coefficient k6; in this embodiment, when Q 剩 / Q 总 When the ratio is above 0.667, it indicates that the total amount of nitrogen oxide emissions from the boiler unit is still relatively large, and there is no need to restrict nitrogen oxide emissions from the boiler unit; the impact on the boiler unit is relatively small. 剩 / Q 总 When the ratio of Q gradually decreases, it indicates that the remaining total amount of nitrogen oxide emissions from the boiler unit is relatively small. At this time, it is necessary to restrict the nitrogen oxide emissions of the boiler unit, and the impact on the boiler unit gradually increases. 剩 / Q 总 When the ratio is 0, it means that the total amount of nitrogen oxide emissions allocated to the boiler unit has been used up. At this time, the alarm and accident handling procedures are triggered to force the boiler unit to shut down.

[0097] In one specific implementation, the specific value of the calculation correction coefficient k6 can be obtained from the relationship table (Table 8) between the residual amount of nitrogen oxide emissions from the boiler unit and the calculation correction coefficient k6.

[0098] In one embodiment, Tables 1 to 8 described in this disclosure are obtained by analyzing and processing long-term operating data of the power plant's boiler units and various tests.

[0099] A second aspect of this disclosure provides a method for maintaining the normal operation of environmental protection facilities in a boiler unit, the method comprising:

[0100] S3. The computer control module obtains the real-time nitrogen oxide emission concentration V0 according to the calculation method described in the first aspect, and the real-time nitrogen oxide emission concentration V0 is subjected to deviation judgment by the deviation judgment module. When the real-time nitrogen oxide emission concentration V0 is outside the control range, the deviation judgment module issues an alarm signal; the control range is 10-50 mg / Nm³. 3 Preferably 20–45 mg / Nm 3 ;

[0101] S4. When the deviation processing module receives the alarm signal issued by the deviation judgment module, the computer control module performs deviation processing.

[0102] Through the above implementation method, the computer control module and the deviation judgment module can determine whether there is a deviation in the real-time nitrogen oxide emission concentration, and perform deviation processing when a deviation occurs. This allows for rapid indication of the cause of the deviation when the real-time nitrogen oxide emission concentration of the boiler unit deviates, thereby ensuring the economic efficiency of the boiler unit's environmental protection facilities operation while avoiding exceeding the pollutant emission concentration standards.

[0103] In one embodiment, the boiler unit used in this disclosure can be controlled in two modes: automatic control and manual control. The automatic control is achieved through a central computer control system.

[0104] In one embodiment, the boiler unit of this disclosure includes a computational control system, which includes a deviation judgment and processing device and a computer control module.

[0105] In one embodiment, the deviation judgment and processing device includes a deviation judgment module and a deviation processing module. The deviation judgment module is pre-installed with control ranges derived from parameters such as national emission standards, ultra-low emission standards, enterprise emission standards, total environmental emissions of the unit, and parameters provided by the equipment manufacturer. When the calculated V0 value is outside the control range, the unit issues an alarm. The deviation processing module receives the alarm information from the deviation judgment module and sends a signal to the computer control module indicating the degree of exceedance. If the computer control module cannot process the error online, it issues a shutdown alarm or an offline processing alarm.

[0106] In one embodiment, the computer control module includes a storage medium, a memory, and a processor. The medium is a non-transitory computer-readable storage medium storing a calculation program. The memory stores the calculation program thereon. The processor executes the calculation program in the memory to implement the calculation program in the storage medium and / or the memory.

[0107] In one embodiment, the deviation processing described in this disclosure includes:

[0108] The computer control module compares the absolute values ​​of the influence levels k1V1, k2V2, k3V3, k4V4, k5V5, and k6V6, and assigns these influence levels in descending order of absolute value as the first processing item, the second processing item, the third processing item, the fourth processing item, the fifth processing item, and the sixth processing item. In this embodiment, the influencing factors corresponding to the one or two influence levels with the largest absolute values ​​are the causes of the fault. The causes of the fault are as follows:

[0109] a. When the absolute value of k1V1 is the largest, it indicates that the fault is caused by abnormal denitrification reaction temperature; the upper limit of the denitrification reaction temperature in this boiler unit is 420℃, the lower limit of the denitrification reaction temperature is 300℃, and the minimum continuous denitrification operation temperature is 290℃.

[0110] b. When the absolute value of k2V2 is the largest, it indicates that the fault is caused by abnormal boiler combustion and / or changes in coal quality.

[0111] c. When the absolute value of k3V3 is the largest, it indicates that the fault is caused by an abnormality in the denitrification device of the boiler unit.

[0112] d. When the absolute value of k4V4 is the largest, it indicates that the fault is caused by the effective volume loss of the denitrification catalyst in the boiler unit.

[0113] e. When the absolute value of k5V5 is the largest, it indicates that the fault is caused by abnormal ammonia injection in the boiler unit.

[0114] f. When the absolute value of k6V6 is at its maximum, the cause of the fault is the limitation on the total nitrogen oxide emissions of the boiler unit.

[0115] In one implementation, the system handles alarms as follows: the calculation program analyzes and determines the item with the largest impact contribution.

[0116] If k1V1, k2V2, k3V3, k4V4, or k5V5 is the first or second treatment item, corresponding measures should be taken according to the abnormality, such as adjusting the denitrification reaction temperature, adjusting the boiler combustion, adjusting the operation of the denitrification device, adjusting the ammonia injection, and replacing the catalyst. After the treatment is completed, the item with the greatest impact is internally shielded or removed, and the calculation continues according to Formula 2. If the calculated value is within the control range, automatic operation is maintained; if the calculated value is outside the control range, manual control mode is switched for treatment or the unit is directly shut down for maintenance.

[0117] If the degree of influence k6V6 is the first processing item, the computer control module allocates the total amount Q of nitrogen oxide emissions from the temporary nitrogen oxide emissions. 临机总Adjustments will be made until the alarm signal is cleared; when the total nitrogen oxide emissions Q are allocated... 临机总 If the allocation index threshold is not met, the computer control module will disable the value of k6V6 and continue the calculation according to Equation 2; or, the control mode of the boiler unit will be switched to manual control. In this embodiment, if the result of the computer control module disabling the value of k6V6 and continuing the calculation according to Equation 2 is still outside the control range, it indicates that automatic control cannot handle the problem. At this time, manual control mode can be switched to handle the problem or the unit can be shut down for maintenance. The allocation index threshold refers to the emission margin of the boiler units adjacent to this unit. This margin is flexibly set according to the parameters and emission indicators of the boiler units adjacent to this unit.

[0118] In one specific implementation, when the influence level k6V6 is the first processing item, the computer control system determines that the alarm signal is caused by the emission limit of total nitrogen oxides. First, the computer control system can automatically adjust the emission limit of total nitrogen oxides from the temporary emission limit until the over-limit alarm is eliminated. If the temporary emission limit of total nitrogen oxides is insufficient, the computer control system can mask k6V6 in Formula 2 and recalculate. If the calculated result after masking is within the control range, the boiler unit will still be in automatic control operation until the computer control system no longer issues an alarm signal, and then the masking item will be restored. If the over-limit alarm cannot be eliminated, the automatic control will be switched to manual control, and the emission limit of nitrogen oxides will be set at 35 mg / Nm³. 3 If the total amount of nitrogen oxides is still insufficient, the emission limit for nitrogen oxides shall be set at 50 mg / Nm³. 3 Run the system; if the total amount of nitrogen oxides still cannot be controlled, request a shutdown.

[0119] The present disclosure is further illustrated below by means of examples, but the present disclosure is not limited thereto. The boiler unit used in this disclosure is manufactured by Shanghai Boiler Factory. The catalyst used in this disclosure is a V2O5 / TiO2 vanadium-based catalyst, purchased from Corning (USA), Topso (Denmark), Chongqing Yuanda, Wuxi Longyuan, Hitachi (Japan), and other companies. The relationship between the calculated correction factor K and the performance degradation parameter Φ and the continuous operating time T of the boiler unit is shown in Table 1; the relationship between the denitrification reaction temperature and the calculated correction factor k1 is shown in Table 2; the relationship between boiler combustion and coal quality changes and the calculated correction factor k2 is shown in Table 3; the relationship between the denitrification differential pressure and time of the boiler unit and the calculated correction factor k3 is shown in Table 4; the relationship between the effective volume loss ratio of the three-layer catalyst and the continuous operating time is shown in Table 5; the relationship between the total effective volume loss ratio of the catalyst of the boiler unit and the calculated correction factor k4 is shown in Table 6; the relationship between the ammonia-nitrogen molar ratio of the boiler unit and the calculated correction factor k5 is shown in Table 7; and the relationship between the residual amount of nitrogen oxide emission distribution of the boiler unit and the calculated correction factor k6 is shown in Table 8.

[0120] Table 1 shows the relationship between the calculated correction factor K and performance degradation parameter Φ and the continuous operating time T of the boiler unit.

[0121] Table 2. Relationship between denitrification reaction temperature and calculation correction factor k1

[0122] Table 3. Relationship between boiler combustion and coal quality changes and the calculation correction factor k2

[0123] Table 4. Relationship between denitrification differential pressure and time of boiler unit and calculation correction coefficient k3

[0124] Table 5. Relationship between the effective volume loss ratio of the three-layer catalyst and the continuous operating time T of the boiler unit.

[0125] Table 6. Relationship between the total effective volume loss percentage of catalyst in boiler units and the calculation correction factor k4.

[0126] Table 7 shows the relationship between the ammonia-nitrogen molar ratio of the boiler unit and the calculation correction factor k5.

[0127] Table 8. Relationship between the remaining amount of nitrogen oxide emissions from boiler units and the calculation correction factor k6.

[0128] Example 1

[0129] Example 1 uses boiler units including Unit 1 and Unit 2; known conditions: boiler factory-guaranteed nitrogen oxide performance value V 保 200 mg / Nm 3 The optimal reaction temperature for the catalyst is 310℃, the minimum allowable continuous reaction temperature is 290℃, and the maximum operating reaction temperature is 410℃; the denitrification efficiency is designed to be 85%; the total nitrogen oxide emissions Q from the two 1,000 MW units of the entire plant are obtained based on the discharge permit approved by the Ecological and Environmental Protection Bureau. 总 The annual output is 960 tons; the number of generating hours (T) for Unit 1 is... 1运 The total operating hours are 4300 hours; Unit 2 was shut down for 500 hours, and the operating hours of Unit 2 are T. 2运 The total nitrogen oxide emissions for Unit 1 are 4800 hours. The total nitrogen oxide emissions for Unit 1 are Q1 = (960 × 4300) / (4300 + 4800) ≈ 453 tons / year, and the total nitrogen oxide emissions for Unit 2 are Q2 = (960 × 4800) / (4300 + 4800) ≈ 507 tons / year.

[0130] The operating status of the boiler unit is divided into normal operating condition and special operating condition based on the continuous operating time T. When T≤2000h, the boiler unit is in normal operating condition; when T>2000h, the boiler unit is in special operating condition.

[0131] Calculate the real-time nitrogen oxide emission concentration V0 of the boiler unit based on its operating status;

[0132] When the boiler unit is under normal operating conditions, the real-time nitrogen oxide emission concentration V0 of the boiler unit is calculated using Equation 1, with the unit being mg / Nm³. 3 V0 = 35 - KTΦ, Equation 1;

[0133] When the boiler unit is under the aforementioned special operating condition, the real-time nitrogen oxide emission concentration V0 of the boiler unit is calculated using Equation 2, with the unit being mg / Nm³. 3 V0 = 35 - [KTΦ + (k1V1 + k2V2 + k3V3 + k4V4 + k5V5 + k6V6)], Equation 2;

[0134] The performance degradation parameter Φ and the calculation correction coefficient K are obtained from Table 1;

[0135] The correction coefficient k1 is calculated according to Table 2, and the influence contribution value V1 is calculated using Equation 3: V1=(V 线 -V 保 )×(1-T1 / T0), Equation 3;

[0136] The correction coefficient k2 is obtained from Table 3, and the influence contribution value V2 is calculated using Equation 4:

[0137] The correction coefficient k3 is calculated according to Table 4, and the influence contribution value V3 is calculated using Equations 5 and 6: t i =V / Q, Equation 6;

[0138] The correction factor k4 is calculated based on Tables 5 and 6, and the contribution value V4 is calculated using Equation 7: V4 = (V 线 -V 保 )×(M'1 / M1+M'2 / M2+M'3 / M3), Equation 7;

[0139] The correction factor k5 is calculated from Table 7, and the contribution value V5 is calculated using Equation 8: V5=(V 线 -V 保 )×(1-Q1 / Q0)×(1-η1 / η 设 Equation 8;

[0140] The correction factor k6 is calculated from Table 8, and the contribution value V5 is calculated using Equations 9 and 10: V6 = (V 线 -V 保 )×(1-Q 剩 / Q 总 Equation 9; Q 剩 =Q 总 -Q y Formula 10.

[0141] The following calculations take Unit 1 as an example. The specific calculations are as follows:

[0142] 1. When the boiler unit's operating time T is 0 hours, according to Table 1, K is 0.8 and Φ is 0.0001: V0 = 35 - KTΦ = 35 - 0.8 × 0 × 0.0001 mg / Nm 3 =35mg / Nm 3 ;

[0143] 2. When the boiler unit operating time T is 1000h, according to Table 1, K is 0.8 and Φ is 0.0001: V0=35-KTΦ=35-0.8×1000×0.0001mg / Nm 3 =34.92mg / Nm 3 ;

[0144] 3. When the boiler unit operating time T is 2000h, according to Table 1, K is 0.8 and Φ is 0.0001: V0=35-KTΦ=35-0.8×2000×0.0001mg / Nm3 =34.84mg / Nm 3 ;

[0145] 4. When the boiler unit operating time T is 2500h, according to Table 1, K is 0.825, Φ is 0.00015, and V... 线 180 mg / Nm 3 The denitrification reaction temperature is 300℃. According to Table 2, when the denitrification reaction temperature T1 is 300℃, the corresponding k1 is 0.958: k1V1=0.958×(180-200)×(1-300 / 310)=-0.618mg / Nm 3 ;

[0146] Parameter N of coal type ar实 It is 0.72%, N ar设 It is 0.71%, T 实 The temperature is 1640℃, T 燃烧 The temperature is 1650℃, and the oxygen content α in the air is 4.5% by volume; according to Table 3, (N ar实 -N ar设 ) / N ar设 =1.4%, k 21 1.000, T 实 -T 燃烧 = -10℃, k 22 k is 1.000 and corresponds to an air oxygen content α of 4.5% by volume. 23 It is 1.000, according to k 21 k 22 and k 23 The comparison yields k2 as 1.000:

[0147] The online denitrification efficiency η1 is 80%, and the denitrification efficiency η2 corresponding to 62 milliseconds is 75%. According to Table 4, the catalyst online differential pressure P1 is 350 kPa, and the design differential pressure P0 is 500 kPa. Since (P1-P0) / P0 = -30% < -5%, therefore kPa... 31 The value is 0.950; the boiler flue gas volume Q is 2,100,000 Nm³. 3 / h=583m 3 / s, catalyst supply volume is 365m³ 3 t was calculated i It is 62 milliseconds, so k 32 It is 1.050; by comparing k 31 and k 32 We know that k3 is 1.050;

[0148] Referring to Table 5, the effective volume loss percentage of the first catalyst layer is 0.15%, the effective volume loss percentage of the second catalyst layer is 0.1%, and the effective volume loss percentage of the third catalyst layer is 0. Referring to Table 6, the total effective volume loss percentage of the three catalyst layers is <1%, so k4 is taken as 1.1; k4V4=1.1×(180-200)×(0.15%+0.1%+0)=-0.055mg / Nm 3 ;

[0149] Q1 is 380 kg / h, Q0 is 420 kg / h, η1 is 80%, and η 设 The value is 85%. Referring to Table 7, (Q1-Q0) / Q0 = -9.5%, so k5 is taken as 1.05; k5V5 = 1.05 × (180-200) × (1-380 / 420) × (1-80% / 85%) = -0.118 mg / Nm³ 3 ;

[0150] The unit 1 has a capacity of Q1 = 453 tons / year, and its capacity after 2500 hours of operation is Q... y1 = 98 tons, Q 剩1 =453-98=355 tons / year; due to Q 剩1 / Q1=0.784>0.667, k6 is 0; k6V6=0×(180-200)×(1-355 / 453)=0mg / Nm 3 ; V0=35-[0.825×2500×0.00015+(-0.618+2.078+0.509-0.055-0.118+0)]=32.895mg / Nm 3 .

[0151] 5. When the boiler unit operating time T is 8000h, according to Table 1, K is 0.9, Φ is 0.0003, and V... 线 230 mg / Nm 3 The denitrification reaction temperature is 305℃. According to Table 2, when the denitrification reaction temperature T1 is 305℃, the corresponding k1 is 0.978: k1V1=0.978×(230-200)×(1-305 / 310)=0.473mg / Nm 3 ;

[0152] Parameter N of coal type ar实 It is 0.73%, N ar设 It is 0.71%, T 实 The temperature is 1660℃, T 燃烧 The temperature was 1650℃, and α was 5.3% by volume; according to Table 3, (N ar实 -N ar设 ) / N ar设 =2.8%, k21 1.000, T 实 -T 燃烧 =10℃, k 22 k = 1.000 and α = 5.3% (volume %) 23 It is 1.150, according to k 21 k 22 and k 23 The comparison yields k2 as 1.150:

[0153] The online denitrification efficiency η1 is 82%, and the denitrification efficiency η2 corresponding to 58 milliseconds is 70%. According to Table 4, the catalyst online differential pressure P1 is 510 kPa, and the design differential pressure P0 is 500 kPa. Since (P1-P0) / P0 = -2%, kPa... 31 The value is 1.000; the boiler flue gas volume Q is 2,250,000 Nm³. 3 / h=625m 3 / s, catalyst supply volume is 365m³ 3 t was calculated i It is 58 milliseconds, so k 32 It is 1.050; by comparing k 31 and k 32 We know that k3 is 1.050;

[0154] Referring to Table 5, the effective volume loss percentage of the first catalyst layer is 0.8%, the second catalyst layer is 0.4%, and the third catalyst layer is 0.1%. Referring to Table 6, the total effective volume loss percentage of the three catalyst layers is 1.3%, and k4 is taken as 1.3. k4V4 = 1.3 × (230 - 200) × (0.8% + 0.4% + 0.1%) = 0.507 mg / Nm³ 3 ;

[0155] Q1 is 410 kg / h, Q0 is 420 kg / h, η1 is 82%, and η 设 The value is 85%. Referring to Table 7, (Q1-Q0) / Q0 = -2.3%, so k5 is taken as 1.05; k5V5 = 1.05 × (230-200) × (1-410 / 420) × (1-82% / 85%) = 0.026 mg / Nm³ 3 ;

[0156] The unit 1 has a capacity of Q1 = 453 tons / year, and its capacity after 8000 hours of operation is Q... y1 = 365.86 tons, Q 剩 1 = 453 - 365.86 = 87.14 tons / year; due to Q 剩1 / Q1=0.192<0.2, k6 is taken as 2; k6V6=2×(230-200)×(1-87.14 / 453)=48.458mg / Nm 3 ; V0=35-[0.9×8000×0.0003+(0.473-3.014-0.764+0.507+0.026+48.453)]=-12.841mg / Nm.

[0157] 6. When the boiler unit operating time T is 15000h, according to Table 1, K is 1.0, Φ is 0.0005, and V... 线 195 mg / Nm 3 The denitrification reaction temperature is 295℃. According to Table 2, when the denitrification reaction temperature T1 is 295℃, the corresponding k1 is 0.925: k1V1=0.925×(195-200)×(1-295 / 310)=-0.224mg / Nm 3 ;

[0158] Parameter N of coal type ar实 It is 0.70%, N ar设 It is 0.71%, T 实 The temperature is 1650℃, T 燃烧 The temperature was 1650℃, and α was 5.5% by volume; according to Table 3, (N ar实 -N ar设 ) / N ar设 <0%, k 21 0.95, T 实 -T 燃烧 =0℃, k 22 k = 1.000 and α = 5.5% (volume %) 23 It is 1.150, according to k 21 k 22 and k 23 After comparison, the maximum value is taken, and k2 is found to be 1.150.

[0159] The online denitrification efficiency η1 is 87%, and the denitrification efficiency η2 corresponding to 66 milliseconds is 76%. According to Table 4, the catalyst online differential pressure P1 is 510 kPa, and the design differential pressure P0 is 500 kPa. Since (P1-P0) / P0 = 24%, kPa... 31 The value is 1.050; the boiler flue gas volume Q is 1,980,000 Nm³. 3 / h=550m 3 / s, catalyst supply volume is 365m³ 3 t was calculated i It is 66 milliseconds, so k 32 It is 1.050; by comparing k31 and k 32 We know that k3 is 1.050;

[0160] Referring to Table 5, the effective volume loss percentage of the first catalyst layer is 1.8%, the second catalyst layer is 1.0%, and the third catalyst layer is 0.5%. Referring to Table 6, the total effective volume loss percentage of the three catalyst layers is 3.3%, and k4 is taken as 2. k4V4 = 2.0 × (195 - 200) × (1.8% + 1.0% + 0.5%) = -0.33 mg / Nm³ 3 ;

[0161] Q1 is 425 kg / h, Q0 is 420 kg / h, η1 is 82%, and η 设 The value is 85%. Referring to Table 7, (Q1-Q0) / Q0 = 1.1%, so k5 is taken as 1.0; k5V5 = 1.0 × (195-200) × (1-425 / 420) × (1-82% / 85%) = 0.002 mg / Nm³ 3 ;

[0162] After 15,000 hours of operation, the total nitrogen oxide emissions from Unit 1 will be subject to the environmental protection bureau's quota for the following year. Therefore, calculations need to be performed in segments, meaning the continuous operating time in the second year is 15,000 - 8,763 = 6,237 hours. Using Q1 = 453 tons / year as the basis, Q is calculated... y1 = 285.2 tons, Q of Unit 1 剩1 =453-285.2=167.8 tons / year; as shown in Table 8, Q 剩1 / Q1=0.370, k6 is taken as 1.5; k6V6=1.5×(195-200)×(1-167.8 / 453)=-4.722mg / Nm 3 ; V0=35-[1.0×15000×0.0005+(-0.224+0.108+0.372-0.33+0.002-4.722)]=32.294mg / Nm.

[0163] 7. When the boiler unit operating time T is 25000h, according to Table 1, K is 1.6, Φ is 0.00085, and V... 线 140 mg / Nm 3 The denitrification reaction temperature is 290℃. According to Table 2, when the denitrification reaction temperature T1 is 290℃, the corresponding k1 is 0.884: k1V1=0.884×(140-200)×(1-290 / 310)=-3.422mg / Nm 3 ;

[0164] Parameter N of coal typear实 It is 0.70%, N ar设 It is 0.71%, T 实 The temperature is 1610℃, T 燃烧 The temperature was 1650℃, and α was 3.0% by volume; according to Table 3, (N ar实 -N ar设 ) / N ar设 <0%, k 21 0.95, T 实 -T 燃烧 = -40℃, k 22 k = 0.850 and α = 3.0 volume % 23 It is 0.850, according to k 21 k 22 and k 23 After comparison, the maximum value is taken, and k2 is found to be 0.950.

[0165] The online denitrification efficiency η1 is 85%, and the denitrification efficiency η2 corresponding to 66 milliseconds is 76%. According to Table 4, the catalyst online differential pressure P1 is 530 kPa, and the design differential pressure P0 is 500 kPa. Since (P1-P0) / P0 = 6%, kPa... 31 The value is 1.050; the boiler flue gas volume Q is 1,980,000 Nm³. 3 / h=550m 3 / s, catalyst supply volume is 365m³ 3 t was calculated i It is 66 milliseconds, so k 32 It is 1.050; by comparing k 31 and k 32 We know that k3 is 1.050;

[0166] Referring to Table 5, the effective volume loss percentage of the first catalyst layer is 5.5%, the second catalyst layer is 3.5%, and the third catalyst layer is 1.2%. Referring to Table 6, the total effective volume loss percentage of the three catalyst layers is 10.2%, and k4 is set to 10. k4V4 = 10 × (140 - 200) × (5.5% + 3.5% + 1.2%) = -61.2 mg / Nm³ 3 ;

[0167] Q1 is 460 kg / h, Q0 is 420 kg / h, η1 is 85%, and η 设 The value is 85%. Referring to Table 7, (Q1-Q0) / Q0 = 0, so k5 is taken as 0.95; k5V5 = 0.95 × (140-200) × (1-460 / 420) × (1-85% / 85%) = 0 mg / Nm3 ;

[0168] After 25,000 hours of operation, the total nitrogen oxide emissions from Unit 1 will be subject to the environmental protection bureau's quota for the third year. This requires segmented calculation, meaning the continuous operating time in the third year is 25,000 - 8763 × 2 = 7474 hours. Using Q1 = 453 tons / year as the basis, Q is calculated... y1 = 341.8 tons, Q of Unit 1 剩1 =453-341.8=111.2 tons / year; as shown in Table 8, Q 剩 1 / Q1=0.245, k6 is 1.5; k6V6=1.5×(140-200)×(1-111.2 / 453)=-67.91mg / Nm 3 ; V0=35-[1.6×25000×0.00085+(-3.422+7.660+1.827-61.200+0-67.910)]=124.045mg / Nm 3 .

[0169] S3. Based on the fault phenomena that occurred when the boiler unit had been running continuously for 8000h and 25000h respectively, the specific details are as follows:

[0170] The calculated result for the boiler unit with a continuous operating time of 8000 hours was negative, triggering an alarm. Comparing the absolute values ​​of k1V1, k2V2, k3V3, k4V4, k5V5, and k6V6, the absolute value of k6V6 is 48.458 mg / Nm³. 3 The maximum value indicates that the cause of the malfunction is insufficient total nitrogen oxide emissions from all units in the plant.

[0171] The calculated result for the boiler unit with a continuous operating time of 25,000 hours is 124.045 mg / Nm³. 3 Greater than 50 mg / Nm 3 The boiler unit issued an alarm. By comparing the absolute values ​​of k1V1, k2V2, k3V3, k4V4, k5V5 and k6V6, it can be seen that the absolute values ​​of k6V6 (67.91) and k4V4 (61.2) are relatively large. Therefore, it can be concluded that the cause of the fault is insufficient total nitrogen oxide emissions of the entire plant unit and excessive loss of effective reaction volume of catalyst.

[0172] S4. For boiler units with a continuous operating time of 8000 hours, the computer control module adjusts the total nitrogen oxide emission allocation Q2 from Unit 2 until the alarm signal is cleared. If the temporary nitrogen oxide emission control target is insufficient, the computer control system can mask k6V6 in Formula 2 and recalculate, obtaining V0 as 35.612 mg / Nm³.3 The alarm has been cleared, and the boiler unit is still operating under automatic control.

[0173] For a boiler unit with an operating time of 25,000 hours, the results indicate that the effective volume loss of the catalyst is significant. This problem cannot be addressed by automatic control. Therefore, the boiler unit will be switched from automatic to manual control, and the catalyst issue will be addressed. If the problem persists, the unit will need to be shut down and the catalyst replaced.

[0174] Analysis of the data in the embodiments shows that: the method of this disclosure compares the calculation results under normal operating conditions and special operating conditions. The data indicates that for boiler units with continuous operating times below 2000 hours and below 15000 hours, the calculation results meet the emission standard of 35 mg / Nm³. 3 The following are within the regulation range of 10–50 mg / Nm 3 Within the normal range; when the boiler unit's continuous operating time is 8000h and 25000h, the calculated results are consistent with the emission standard of 35mg / Nm³. 3 Significant deviations occurred within the control range of 10–50 mg / Nm 3 In addition, analysis revealed that the cause of the malfunction was insufficient total nitrogen oxide emissions from all units in the plant. The judgment method disclosed herein can accurately reflect the causes of malfunctions during continuous operation of the boiler unit, thereby ensuring the economic efficiency of the boiler unit's environmental protection facilities while preventing excessive pollutant emission concentrations.

[0175] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0176] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0177] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A method for calculating the real-time nitrogen oxide emission concentration of a boiler unit online, characterized in that, The calculation method includes: S1. Determine the current operating condition of the boiler unit based on the continuous operating time T of the boiler unit; when the continuous operating time T of the boiler unit is less than 2000h, the operating condition is a normal operating condition; when the continuous operating time T of the boiler unit is greater than 2000h, the operating condition is a special operating condition. S2. Calculate the real-time nitrogen oxide emission concentration V0 of the boiler unit based on the operating conditions of the boiler unit; When the boiler unit is under normal operating conditions, the real-time nitrogen oxide emission concentration V0 of the boiler unit is calculated using Equation 1, with the unit being mg / Nm³. 3 : V0 = 35 - KTΦ, Equation 1; When the boiler unit is under the aforementioned special operating condition, the real-time nitrogen oxide emission concentration V0 of the boiler unit is calculated using Equation 2, with the unit being mg / Nm³. 3 : V0 = 35 - [KTΦ + (k1V1 + k2V2 + k3V3 + k4V4 + k5V5 + k6V6)], Equation 2; In the formula: K refers to the calculation correction factor for the boiler unit, which is dimensionless; T refers to the continuous operating time of the boiler unit, in hours; Φ refers to the performance degradation value of the boiler unit catalyst, in mg / Nm³. 3 .H; V1 refers to the contribution of the catalyst reaction temperature of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, expressed in mg / Nm³. 3 k1 refers to the calculation correction coefficient for the catalyst reaction temperature of the boiler unit, which is dimensionless. V2 refers to the contribution value of the combustion and coal quality changes of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, expressed in mg / Nm³. 3 k2 refers to the calculation correction coefficient for boiler combustion and coal quality changes of the boiler unit, which is dimensionless. V3 refers to the contribution value of the denitrification reaction time of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm³. 3 k3 refers to the calculation correction coefficient for the denitrification differential pressure and time of the boiler unit, which is dimensionless. V4 refers to the contribution of the effective reaction volume of the catalyst in the boiler unit to the nitrogen oxide emission concentration of the boiler unit, expressed in mg / Nm³. 3 k4 refers to the calculation correction factor for the effective volume of the catalyst in the boiler unit, which is dimensionless. V5 refers to the contribution of the ammonia-nitrogen molar ratio of the boiler unit to the nitrogen oxide emission concentration of the boiler unit. Value, unit is mg / Nm 3 k5 refers to the calculation correction factor for the ammonia-nitrogen molar ratio of the boiler unit, which is dimensionless. V6 refers to the contribution value of the total nitrogen oxide emission constraint of the entire plant's units to the nitrogen oxide emission concentration of the boiler unit, expressed in mg / Nm³. 3 k6 refers to the calculation correction coefficient for the total nitrogen oxide emission control of the boiler unit, which is dimensionless.

2. The method according to claim 1, characterized in that, The performance degradation parameter Φ and the calculation correction coefficient K are obtained from the relationship table of the continuous operating time T of the boiler unit.

3. The method according to claim 1, characterized in that, The influence contribution value V1 is calculated using Equation 3: V1=(V 线 -V 保 )×(1-T1 / T0), Equation 3; In the formula: V 线 This refers to the online measured concentration of nitrogen oxides in the boiler unit, expressed in mg / Nm³. 3 ; V 保 This refers to the factory-guaranteed nitrogen oxide concentration performance value of the boiler unit, in mg / Nm³. 3 ; T1 refers to the real-time reaction temperature of the denitrification device of the boiler unit, in °C. T0 refers to the optimal reaction temperature of the denitrification device of the boiler unit, in °C. The calculation correction coefficient k1 is obtained based on the denitrification reaction temperature of the boiler unit.

4. The method according to claim 1, characterized in that, The influence contribution value V2 is calculated using Equation 4: In the formula: N ar实 This refers to the nitrogen content in the actual coal type of the boiler unit, expressed in weight %; N ar设 This refers to the nitrogen content in the coal type designed for the boiler unit, expressed in weight %; T 实 This refers to the flame center temperature during pulverized coal combustion in the boiler unit, expressed in °C. T 燃烧 This refers to the theoretical flame center temperature during pulverized coal combustion in the boiler unit, expressed in °C. α refers to the oxygen content of the air during pulverized coal combustion in the boiler unit, expressed as a percentage by volume. The correction coefficient k2 is calculated based on the parameters of coal type variation, combustion temperature variation, and air oxygen content α.

5. The method according to claim 1, characterized in that, The influence contribution value V3 is calculated using Equation 5: In the formula: P1 refers to the actual differential pressure of the catalyst in the boiler unit during operation, in kPa. P0 refers to the differential pressure of the catalyst in the boiler unit during theoretical operation, and the unit is kPa; η1 refers to the actual denitrification efficiency of the boiler unit, expressed in %; η2 refers to the reaction time t between the flue gas and ammonia mixture and the catalyst in the boiler unit. i The corresponding denitrification efficiency is expressed in %. The calculation correction factor k3 is based on the catalyst differential pressure and the catalyst-flue gas contact time t of the boiler unit. i get; The contact time t between the catalyst and the flue gas i The result is obtained through calculation using Equation 6: t i =V / Q, Equation 6; In the formula: Q refers to the actual amount of flue gas flowing through the catalyst in the boiler unit, measured in m³. 3 / s; V refers to the hollow volume of the catalyst channel in the boiler unit, measured in meters (m). 3 ; t i This refers to the time it takes for the flue gas and ammonia mixture to pass through the catalyst channel in the boiler unit, measured in seconds.

6. The method according to claim 1, characterized in that, The impact contribution value V4 is calculated using Equation 7: V4 = (V 线 -V 保 )×(M'1 / M1+M'2 / M2+M'3 / M3), Equation 7; In the formula: M'1 refers to the effective volume loss of the first layer of catalyst in the boiler unit, in m³. 3 ; M1 refers to the effective volume of the first layer of catalyst in the boiler unit when it was brand new, and the unit is m³. 3 ; M'2 refers to the effective volume loss of the second layer catalyst in the boiler unit, measured in m³. 3 ; M2 refers to the original, brand-new effective volume of the second layer catalyst in the boiler unit, measured in m³. 3 ; M'3 refers to the effective volume loss of the third layer catalyst in the boiler unit, measured in m³. 3 ; M3 refers to the effective volume of the third layer catalyst of the boiler unit when it was brand new, in cubic meters (m³). 3 ; The calculation correction coefficient k4 is obtained based on the total effective volume loss ratio of the three-layer catalyst.

7. The method according to claim 1, characterized in that, The influence contribution value V5 is calculated using Equation 8: V5 = (V 线 -V 保 )×(1-Q1 / Q0)×(1-η1 / η 设 Equation 8; In the formula: Q1 refers to the actual ammonia injection rate of the denitrification unit in the boiler unit, m 3 / s; Q0 refers to the theoretical ammonia injection rate of the denitrification unit in the boiler unit, m 3 / s; η1 refers to the actual denitrification efficiency of the boiler unit, expressed in %; η 设 This refers to the design denitrification efficiency of the boiler unit, expressed in %. The calculation correction coefficient k5 is obtained based on the ammonia injection rate of the boiler unit.

8. The method according to claim 1, characterized in that, The impact contribution value V6 is calculated using Equation 9: V6 = (V 线 -V 保 )×(1-Q 剩 / Q 总 Equation 9; In the formula: Q 剩 This refers to the remaining amount of nitrogen oxide emissions from the boiler unit, expressed in t / a. Q 总 This refers to the total nitrogen oxide emission distribution Q of the boiler unit. 总 The unit is t / a; The calculation correction factor k6 is obtained based on the nitrogen oxide emissions of the boiler unit; The remaining nitrogen oxide emission allocation Q of the boiler unit is calculated using Equation 10. 剩 : Q 剩 =Q 总 -Q y , Equation 10; In the formula, Q y This refers to the allocation and usage of nitrogen oxide emissions from the boiler unit. The remaining amount Q is allocated according to the nitrogen oxide emissions of the boiler unit. 剩 The total nitrogen oxide emissions Q of the boiler unit 总 The ratio is used to obtain the calculated correction coefficient k6.

9. A method for maintaining the normal operation of environmental protection facilities in a boiler unit, characterized in that, The method includes: S3. The computer control module obtains the real-time nitrogen oxide emission concentration V0 according to the calculation method of any one of claims 1 to 8, and the real-time nitrogen oxide emission concentration V0 is subjected to deviation judgment by the deviation judgment module. When the real-time nitrogen oxide emission concentration V0 is outside the control range, the deviation judgment module issues an alarm signal; the control range is 10 to 50 mg / Nm³. 3 ; S4. When the deviation processing module receives the alarm signal issued by the deviation judgment module, the computer control module performs deviation processing.

10. The method according to claim 9, characterized in that, The deviation processing includes: The computer control module compares the absolute values ​​of the influence levels k1V1, k2V2, k3V3, k4V4, k5V5, and k6V6, and assigns the influence levels in descending order of absolute value as the first processing item, the second processing item, the third processing item, the fourth processing item, the fifth processing item, and the sixth processing item. When the degree of influence k6V6 is the first processing item, the computer control module allocates the total amount Q of nitrogen oxide emissions from the temporary nitrogen oxide emissions. 临机总 Adjustments were made until the alarm signal was cleared; When the total amount of nitrogen oxide emissions Q is allocated 临机总 If the allocation threshold is not met, the computer control module will disable the value of k6V6 and continue to calculate according to Equation 2; or, the control mode of the boiler unit will be switched to manual control.

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