A method for calculating the online nitrogen oxide emission concentration of a boiler unit and a method for judging and handling deviations

Abstract

The present disclosure relates to a method for calculating the online nitrogen oxide emission concentration of a boiler unit and a method for determining and handling deviations. The method divides the operating state of the boiler unit into normal operating conditions and special operating conditions based on the continuous operating time T of the boiler unit, and calculates the online nitrogen oxide emission concentration of the boiler unit when in normal operating conditions or special operating conditions using a formula. This method can quantify the factors affecting the normal operation of the boiler unit, clearly display the impact of each factor on the boiler unit, and thus guide personnel in adjusting the boiler unit. In addition, a computer control module and a deviation determination module are used to determine whether the online nitrogen oxide emission concentration has deviated, and if so, perform deviation handling. When the online nitrogen oxide emission concentration of the boiler unit deviates, the cause of the deviation can be quickly indicated, thereby ensuring the economic efficiency of the boiler unit operation while preventing the boiler unit from exceeding emission standards.

Description

Technical Field

[0001] The present disclosure relates to the field of flue gas emissions from boiler units, and more particularly to a method for calculating the online nitrogen oxide emission concentration of a boiler unit and a method for judging and processing deviations. Background Art

[0002] Operators were unable to accurately assess the relationship between the plant's total permitted emissions, NOx emission concentrations, and unit operating hours. Units operated for extended periods, potentially exceeding environmentally friendly NOx emission standards. Furthermore, there was no formula for calculating the optimal NOx emission concentration for online operation. Relying on operator experience and setting these concentrations, the system's economic operation was suboptimal. Summary of the Invention

[0003] The purpose of the present disclosure is to provide a method for calculating the online nitrogen oxide emission concentration of a boiler unit and a method for judging and handling deviations, so as to solve the problem that there is no calculation formula for the optimal nitrogen oxide emission concentration during continuous operation in the prior art; and to solve the problem of relying on the experience of operators to make judgments and settings.

[0004] To achieve the above objectives, the present disclosure provides, in a first aspect, a method for calculating the online nitrogen oxide emission concentration of a boiler unit, the method comprising:

[0005] S1. Determine the current operating state 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 2000 hours, the operating state is a normal operating state; when the continuous operating time T of the boiler unit is greater than 2000 hours, the operating state is a special operating state;

[0006] S2. Calculating the online nitrogen oxide emission concentration V0 of the boiler unit according to the operating state of the boiler unit;

[0007] When the boiler unit is in the normal operating state, the online nitrogen oxide emission concentration V0 of the boiler unit is calculated using formula 1, in mg / Nm 3 :

[0008] V0=35-KTΦ,Equation 1

[0009] When the boiler unit is in the special operating state, the online nitrogen oxide emission concentration V0 of the boiler unit is calculated using formula 2, in mg / Nm 3 :

[0010] V0=35-[KTΦ+(k1V1+k2V2+k3V3+k4V4+k5V5+k6V6)], Formula 2

[0011] Where: K refers to the calculation correction coefficient of the boiler unit, which is dimensionless; T refers to the continuous operation time of the boiler unit, in hours; Φ refers to the performance attenuation parameter of the boiler unit, in mg / Nm 3 .H; V1 refers to the contribution of the reaction temperature of the catalyst of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm 3 k1 refers to the calculation correction coefficient of the catalyst reaction temperature of the boiler unit, which is dimensionless; V2 refers to the contribution of the combustion of the boiler unit and the change of coal quality to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm 3 k2 refers to the calculation correction coefficient of the boiler unit's boiler combustion and coal quality changes, which is dimensionless; V3 refers to the contribution value of the boiler unit's denitrification reaction time to the boiler unit's nitrogen oxide emission concentration, in mg / Nm 3 k3 refers to the calculation correction coefficient of the denitration 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 / Nm 3 k4 refers to the calculation correction coefficient of the effective volume of the catalyst of 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 / Nm 3 k5 refers to the calculation correction coefficient of the ammonia nitrogen molar ratio of the boiler unit, which is dimensionless; V6 refers to the contribution value of the total nitrogen oxide emission control of the whole plant unit to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm 3 ; k6 refers to the calculation correction coefficient for the emission control of the total amount of nitrogen oxides of the boiler unit, which is dimensionless.

[0012] Optionally, the performance degradation parameter Φ and the calculation correction coefficient K are obtained according to a relationship table of the calculation correction coefficient K, the performance degradation parameter Φ and the continuous operation time T of the boiler unit.

[0013] Optionally, the impact contribution value V1 is calculated by Formula 3:

[0014] V1=(V 线 -V 保 )×(1-T1 / T0), Formula 3

[0015] Where: V 线 Refers to the online measurement concentration of nitrogen oxides of the boiler unit, in mg / Nm 3 ; V 保 Refers to the guaranteed nitrogen oxide concentration performance value of the boiler unit at the factory, in mg / Nm3 ; T1 refers to the real-time reaction temperature of the denitration device of the boiler unit, in °C; T0 refers to the optimal reaction temperature of the denitration device of the boiler unit, in °C; the calculation correction coefficient k1 is obtained based on the reaction temperature of the catalyst in the boiler unit.

[0016] Optionally, the impact contribution value V2 is calculated by Formula 4:

[0017]

[0018] Where: N ar实 Refers to the nitrogen content in the actual coal type of the boiler unit, in %; N ar设 Refers to the nitrogen content in the design coal type of the boiler unit, in %; T 实 It refers to the flame center temperature of the boiler unit when the pulverized coal is burning in the furnace, in °C; T 燃烧 It refers to the theoretical flame center temperature when the furnace coal powder of the boiler unit is burning, and the unit is ℃; α refers to the air oxygen content when the furnace coal powder of the boiler unit is burning, and the unit is %. The calculation correction coefficient k2 is obtained based on the coal type change parameter, combustion temperature change parameter and air oxygen content α.

[0019] Optionally, the impact contribution value V3 is calculated by Formula 5:

[0020]

[0021] Where: P1 refers to the actual operating differential pressure of the catalyst of the boiler unit, in kPa; P0 refers to the theoretical operating differential pressure of the catalyst of the boiler unit, in kPa; η1 refers to the actual denitrification efficiency of the boiler unit, in %; η2 refers to the reaction time t of the flue gas and ammonia mixture in contact with the catalyst of the boiler unit i The corresponding denitrification efficiency is expressed in %; the calculation correction coefficient k3 is calculated based on the catalyst differential pressure of the boiler unit and the contact time t between the catalyst and the flue gas. i get;

[0022] The contact time between the catalyst and the flue gas is t i Calculated by formula 6:

[0023] t i =V / Q, Equation 6

[0024] Where: Q refers to the actual flue gas volume flowing through the catalyst of the boiler unit, in m 3 / s; V refers to the hollow volume of the catalyst channel of the boiler unit, in m 3 ;t iIt refers to the reaction time of the flue gas and ammonia mixture of the boiler unit in contact with the catalyst, in ms.

[0025] Optionally, the impact contribution value V4 is calculated by formula 7:

[0026] V4=(V 线 -V 保 )×(M′1 / M1+M′2 / M2+M′3 / M3), Equation 7

[0027] Where: M1' refers to the effective volume loss of the first layer of catalyst of the boiler unit, unit is m 3 ; M1 refers to the effective volume of the first layer of catalyst of the boiler unit when it is new, in m 3 ; M2' refers to the effective volume loss of the second layer catalyst of the boiler unit, in m 3 ; M2 refers to the effective volume of the second layer of catalyst of the boiler unit when it is new, in m 3 ; M3' refers to the effective volume loss of the third layer catalyst of the boiler unit, in m 3 ; M3 refers to the effective volume of the third layer of catalyst of the boiler unit when it is new, in m 3 ; The calculation correction coefficient k4 is obtained based on the total effective volume loss ratio of the three-layer catalyst.

[0028] Optionally, the impact contribution value of V5 is calculated by Formula 8:

[0029] V5=(V 线 -V 保 )×(1-Q1 / Q0)×(1-η1 / η 设 ), Equation 8

[0030] Where: Q1 refers to the actual ammonia injection amount of the denitrification device in the boiler unit, m 3 / s; Q0 refers to the theoretical ammonia injection amount of the denitrification device in the boiler unit, m 3 / s; η1 refers to the actual denitrification efficiency of the boiler unit, in %; η 设 It refers to the designed denitrification efficiency of the boiler unit, in %. The calculation correction coefficient k5 is obtained according to the ammonia injection amount of the boiler unit.

[0031] Optionally, the impact contribution value of V6 is calculated by formula 9:

[0032] V6=(V 线 -V 保 )×(1-Q 剩 / Q 总 ), Equation 9

[0033] Where: Q 剩 It refers to the residual amount of nitrogen oxide emissions allocated by the boiler unit, in t / a; Q 总 Refers to the total amount of nitrogen oxide emissions allocated to the boiler unit Q 总 , unit is t / a;

[0034] The NO of the boiler unit is calculated by formula 10. X Emission allocation remainder Q 剩 :

[0035] Q 剩 =Q 总 -Q y , Equation 10

[0036] Where Q y Refers to the nitrogen oxide emission allocation usage of the boiler unit; the calculation correction coefficient k6 is based on the nitrogen oxide emission allocation remaining amount Q of the boiler unit 剩 The total amount of nitrogen oxide emissions allocated to the boiler unit Q 总 The ratio is worth getting.

[0037] A second aspect of the present disclosure provides a method for determining and processing an online nitrogen oxide emission concentration deviation, the method comprising:

[0038] S3. The computer control module obtains the online nitrogen oxide emission concentration V0 according to the calculation method described in the first aspect, and the online nitrogen oxide emission concentration V0 is subjected to deviation judgment by the deviation judgment module. When the online 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 / Nm 3 ;

[0039] S4. When the deviation processing module receives the alarm signal sent by the deviation judgment module, it enables the computer control module to perform deviation processing.

[0040] Optionally, the deviation processing includes: making the computer control module compare the absolute values ​​of the influence levels k1V1, k2V2, k3V3, k4V4, k5V5 and k6V6, and setting the influence levels 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 descending order according to the absolute value; when the influence level k6V6 is the first processing item, making the computer control module allocate the total amount of nitrogen oxide emissions Q from the machine 临机总 Adjust until the alarm signal is eliminated; when the total amount of nitrogen oxide emissions Q 临机总When the allocation index threshold is not met, the computer control module blocks the value of k6V6 and continues to calculate according to Formula 2; or, the control mode of the boiler unit is switched from automatic control to manual control.

[0041] Through the above technical solution, the operating state of the boiler unit is divided into normal operating state and special operating state according to the continuous operation time T of the boiler unit. The online nitrogen oxide emission concentration of the boiler unit in normal operating state or special operating state is calculated by formula. This can quantify the factors affecting the normal operation of the boiler unit, clearly display the impact of each factor on the boiler unit, and thus guide personnel to adjust the boiler unit. In addition, the computer control module and deviation judgment module determine whether the online nitrogen oxide emission concentration has deviated and perform deviation processing if a deviation occurs. When the online nitrogen oxide emission concentration of the boiler unit deviates, the cause of the deviation can be quickly indicated, thereby ensuring the economic operation of the boiler unit while preventing the boiler unit from exceeding the emission standard.

[0042] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0044] Figure 1 The present invention discloses a flow chart of a method for determining and processing an online nitrogen oxide emission concentration deviation. DETAILED DESCRIPTION

[0045] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0046] A first aspect of the present disclosure provides a method for calculating the online nitrogen oxide emission concentration of a boiler unit, the method comprising:

[0047] S1. Determine the current operating state 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 2000 hours, the operating state is a normal operating state; when the continuous operating time T of the boiler unit is greater than 2000 hours, the operating state is a special operating state;

[0048] S2. Calculating the online nitrogen oxide emission concentration V0 of the boiler unit according to the operating status of the boiler unit;

[0049] When the boiler unit is in the normal operating state, the online nitrogen oxide emission concentration V0 of the boiler unit is calculated using formula 1, in mg / Nm 3 :

[0050] V0=35-KTΦ, Formula 1

[0051] When the boiler unit is in the special operating state, the online nitrogen oxide emission concentration V0 of the boiler unit is calculated using formula 2, in mg / Nm 3 :

[0052] V0=35-[KTΦ+(k1V1+k2V2+k3V3+k4V4+k5V5+k6V6)], Formula 2

[0053] Where: K refers to the calculation correction coefficient of the boiler unit, which is dimensionless; T refers to the continuous operation time of the boiler unit, in hours; Φ refers to the performance attenuation parameter of the boiler unit, in mg / Nm 3 .H; V1 refers to the contribution of the reaction temperature of the catalyst of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm 3 k1 refers to the calculation correction coefficient of the catalyst reaction temperature of the boiler unit, which is dimensionless; V2 refers to the contribution of the combustion of the boiler unit and the change of coal quality to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm 3 k2 refers to the calculation correction coefficient of the boiler unit's boiler combustion and coal quality changes, which is dimensionless; V3 refers to the contribution value of the boiler unit's denitrification reaction time to the boiler unit's nitrogen oxide emission concentration, in mg / Nm 3 k3 refers to the calculation correction coefficient of the denitration 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 / Nm 3 k4 refers to the calculation correction coefficient of the effective volume of the catalyst of 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 / Nm 3 k5 refers to the calculation correction coefficient of the ammonia nitrogen molar ratio of the boiler unit, which is dimensionless; V6 refers to the contribution value of the total nitrogen oxide emission control of the plant units to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm 3 ; k6 refers to the calculation correction coefficient for the total nitrogen oxide emission control of the boiler unit, which is dimensionless;

[0054] Through the above-described embodiment, the operating state of the boiler unit is divided into normal operating state and special operating state according to the continuous operation time T of the boiler unit. The online nitrogen oxide emission concentration of the boiler unit in normal operating state or special operating state is calculated using a formula. This quantifies the factors affecting the normal operation of the boiler unit, clearly displays the impact of each factor on the boiler unit, and thus guides personnel in adjusting the boiler unit. Furthermore, the computer control module and the deviation judgment module determine whether the online nitrogen oxide emission concentration has deviated and, if so, handle the deviation. This allows for rapid indication of the cause of the deviation in the online nitrogen oxide emission concentration of the boiler unit, thereby ensuring the economic efficiency of the boiler unit's operation while preventing excessive emissions from the boiler unit.

[0055] In one embodiment, when the continuous operation time of the boiler unit is less than 2000 hours, the hydrogenation reaction conditions, boiler combustion conditions, denitrification unit operating conditions, catalyst properties, and ammonia injection unit operating conditions, among others, have a relatively small impact on the boiler unit's online nitrogen oxide emission concentration V0. Therefore, the impact of each influencing factor on the nitrogen oxide emission concentration can be ignored. In this case, Equation 2 can be simplified to obtain Equation 1, i.e., the specific boiler unit's online nitrogen oxide emission concentration V0 can be calculated using Equation 1. When the continuous operation time of the boiler unit is greater than 2000 hours, the hydrogenation reaction conditions, boiler combustion conditions, denitrification unit operating conditions, catalyst properties, and ammonia injection unit operating conditions, among others, all have a significant impact on the boiler unit's online nitrogen oxide emission concentration V0. Therefore, the specific boiler unit's online nitrogen oxide emission concentration V0 can be calculated using Equation 2. The degree of impact can be represented by the product of the corresponding impact contribution value and the calculation correction coefficient (k1V1, k2V2, k3V3, k4V4, k5V5, and k6V6).

[0056] In one embodiment, the value 35 in Formula 1 and Formula 2 refers to the ultra-low emission limit of nitrogen oxides for coal-fired units, in mg / Nm 3 Among them, the ultra-low emission limit of nitrogen oxides for coal-fired units is implemented according to the upper limit of the standard (NO X ≤100mg / Nm 3 ), ultra-low emission control standard upper limit (NO X ≤50mg / Nm 3 ) and the upper limit of environmental assessment implementation standards (NO X ≤35mg / Nm 3 ) obtained after evaluation.

[0057] In a preferred embodiment, the enterprise standard limit range of online nitrogen oxide emission concentration is: 10mg / Nm 3 ≤NOX ≤35mg / Nm 3 In this implementation, the enterprise standard is obtained by each factory based on the evaluation of relevant parameters of the boiler unit. The ultra-low emission limit of nitrogen oxides of coal-fired units can be adjusted to 35-△, where △ is the unit adjustment safety margin, which can be set to 1 to 10, in mg / Nm 3 The safety margin can be set according to the parameters of the boiler unit of each manufacturer. For example, the parameters of the boiler unit include: Ammonia escape rate upper and lower limit settings: Ammonia escape upper limit: 2.5mg / Nm 3 ; No lower limit; Upper limit of denitrification efficiency: 95%; Lower limit of denitrification efficiency: 40%; Upper limit of denitrification reaction temperature: 420℃; Lower limit of denitrification reaction temperature: 250℃; Minimum continuous operation temperature of denitrification: 290℃; Normal reaction time of catalyst: 200 milliseconds; Lower limit of catalyst reaction time: 50 milliseconds.

[0058] In one embodiment, after the boiler unit is put into operation, it will show a performance degradation phenomenon, wherein the performance degradation parameter Φ and the calculation correction coefficient K can be obtained based on the continuous operation time T of the boiler unit. The performance degradation value Φ of the boiler unit described in the present disclosure can be a value within the range of 0.0001 to 0.0009, for example, the performance degradation value 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 the present disclosure is a conventional boiler unit in the art, for example, the boiler unit includes a combustion device and a denitration reaction device. The calculation correction coefficient K of the boiler unit disclosed in the present invention may be a value within the range of 0.800 to 2.000. For example, the performance degradation value Φ may be 0.800, 0.850, 0.900, 0.950, 1.000, 1.100, 1.300, 1.500, and 2.000.

[0059] In a specific embodiment, the values ​​of the performance degradation parameter Φ and the calculation correction coefficient K can be obtained according to a selection table (Table 1) of the calculation correction coefficient K, the performance degradation parameter Φ and the continuous operation time T of the boiler unit.

[0060] In one embodiment, the combustion device of the boiler unit is a conventional choice in the art, and this application does not make special requirements. For example, the combustion device is a low-nitrogen burner. The upper and lower limits of nitrogen oxide pollution produced by the low-nitrogen burner are given by the boiler manufacturer. The upper limit of nitrogen oxide pollution produced by the low-nitrogen burner used in this disclosure is NO X ≤300mg / Nm 3 The lower limit of pollution is NO X ≤50mg / Nm 3 .

[0061] In this embodiment, the boiler material is burned in the combustion device, and the flue gas produced contains NO X , among which, NO X It is mainly composed of NO and NO2, with NO accounting for more than 90% of the total. NH3 and the flue gas generated by the combustion device enter the denitrification reaction device and contact with the catalyst for denitrification reaction, which can selectively remove NO in the flue gas. X Reduced to non-toxic and non-polluting N2 and H2O. When the temperature of the denitrification reaction is 300-350℃, the following reaction occurs in the denitrification device: 4NH3+4NO+O2=4N2+6H2O or 4NH3+2NO+O2=3N2+6H2O; when the temperature of the denitrification reaction is below 300℃, the following reaction occurs in the denitrification device: 4NH3+3O2=2N2+6H2O+1267.1KJ; when the temperature of the denitrification reaction is above 350℃, the following reaction occurs in the denitrification device: 2NH3=N2+3H2-91.9KJ or 4NH3+5O2=4NO+6H2O+907.3KJ. The kinetic principles of the denitrification reaction mainly include: NO X , NH3 and O2 diffuse from the flue gas to the outer surface of the catalyst; NO X , NH3 and O2 further diffuse to the microporous surface of the catalyst; gaseous NO X The N2 and H2O react with the NH3 adsorbed on the active centers 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 flow and are carried away.

[0062] In one embodiment, the catalyst used in the denitration 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.

[0063] In one embodiment, the impact contribution value V1 and the calculation correction coefficient k1 are related to the denitration reaction temperature of the catalyst of the denitration device, wherein the impact contribution value V1 is calculated by formula 3:

[0064] V1=(V 线 -V 保 )×(1-T1 / T0), Formula 3

[0065] Where: V 线 Refers to the online measurement concentration of nitrogen oxides of the boiler unit, in mg / Nm 3 ; V 保 Refers to the guaranteed nitrogen oxide concentration performance value of the boiler unit at the factory, in mg / Nm 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.

[0066] In one embodiment, the calculation correction coefficient k1 can be obtained based on a table (Table 2) showing the relationship between the denitration reaction temperature of the boiler unit's catalyst and the calculation correction coefficient k1. In this embodiment, the table (Table 2) showing the relationship between the denitration reaction temperature of the boiler unit's catalyst and the correction coefficient k1 is related to the parameters of the boiler unit and is obtained by summarizing relevant data from long-term use of the boiler unit.

[0067] In one embodiment, the impact contribution value V2 and the calculation correction coefficient k2 are related to the change of coal type, combustion temperature and air oxygen content α, wherein the impact contribution value V2 is calculated by

[0068] Formula 4 calculates:

[0069]

[0070] Where: N ar实 Refers to the nitrogen content in the actual coal type of the boiler unit, in %; N ar设 Refers to the nitrogen content in the design coal type of the boiler unit, in %; T 实 It refers to the flame center temperature of the boiler unit when the pulverized coal is burning in the furnace, in °C; T 燃烧 It refers to the theoretical flame center temperature when the pulverized coal in the furnace of the boiler unit is burning, and the unit is ℃; α refers to the oxygen content of the air when the pulverized coal in the furnace of the boiler unit is burning, and the unit is %.

[0071] In one embodiment, the change of the coal type can be represented by the coal type change parameter, and the coal type change parameter can be represented by (N ar实 -N ar设 ) / N ar设 Quantification; the combustion temperature change can be expressed by the combustion temperature change parameter, and the coal type change parameter can be expressed by T 实 -T 燃烧 Quantification; the air oxygen content α can be obtained by an oxygen content detection device provided in the air intake chamber.

[0072] In one embodiment, the calculation correction coefficient k2 can be obtained based on a relationship table (Table 3) between boiler combustion and coal quality changes and the calculation correction coefficient k2, which is obtained by summarizing relevant data of the long-term use of the boiler unit.

[0073] In a preferred embodiment, the obtained coal type variation parameters, combustion temperature variation parameters and air oxygen content α are compared with the relationship table of boiler combustion and coal quality variation and calculation correction coefficient k2 (Table 3). Specifically, the first calculation correction coefficient k is obtained according to the coal type variation parameters. 21 , the second calculation correction coefficient k is obtained according to the combustion temperature change parameter 22 , the third calculation correction coefficient k is obtained according to the air oxygen content α 23 ; By comparing the first calculated correction coefficient k 21 , the second calculation correction coefficient k 22 and the third calculation correction coefficient k 23 The calculation correction coefficient with the largest value among the three is the calculation correction coefficient k2.

[0074] In one embodiment, if the change in the nitrogen content of the coal cannot be detected online or the combustion temperature cannot be measured, Formula 4 can be replaced and transformed to obtain Formula 4-1, and the impact contribution value V2 can be obtained through Formula 4-1:

[0075] V2=(V 线 -V 保 )×(1-V 线 / V 保 +▲), Formula 4-1

[0076] Where: ▲ refers to the compensation value of the combustion state of the boiler unit and the change of coal type, the unit is mg / Nm 3 The compensation value can be calculated based on Table 3 and the coal-fired and combustion characteristics of the boiler unit, the unit furnace outlet online monitoring temperature and the unit coal-fired amount, and the fixed compensation value of different states is set.

[0077] In one embodiment, the influence contribution value V3 and the calculation correction coefficient k3 are related to the catalyst differential pressure of the denitration reaction and the contact time t between the catalyst and the flue gas. i Related. 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, the ammonia gas sprayed from the ammonia spraying device of the denitrification device and the flue gas are brought into contact in the denitrification device to conduct a time influence test, and a denitrification time efficiency relationship diagram is obtained. It can be seen from the denitrification time efficiency relationship diagram that the denitrification efficiency increases with the increase of contact time. When the contact time reaches 200 milliseconds, the denitrification efficiency reaches the maximum, and then the denitrification efficiency decreases. When the contact time of NH3 gas and the catalyst gradually increases, it is conducive to the diffusion, adsorption, reaction of NH3 gas in the pores of the catalyst and the desorption and diffusion of the product gas, thereby improving the denitrification efficiency. If the contact time is too long, the NH3 gas will undergo an oxidation reaction, reduce the reducing medium, and the denitrification efficiency will decrease instead.

[0078] In one embodiment, the impact contribution value V3 is calculated by formula 5:

[0079]

[0080] Where: P1 refers to the actual operating differential pressure of the catalyst of the boiler unit, in kPa; P0 refers to the theoretical operating differential pressure of the catalyst of the boiler unit, in kPa; η1 refers to the actual denitrification efficiency of the boiler unit, in %; η2 refers to the reaction time t of the flue gas and ammonia mixture in contact with the catalyst of the boiler unit i The corresponding denitrification efficiency is in %.

[0081] In one embodiment, the catalyst differential pressure of the boiler unit can be quantified by (P1-P0) / P0, and the contact time between the catalyst and the flue gas is t i Calculated by formula 6:

[0082] t i =V / Q, Equation 6

[0083] Where: Q refers to the actual flue gas volume flowing through the catalyst of the boiler unit, in m 3 / s; V refers to the hollow volume of the catalyst channel of the boiler unit, in m 3 ;t i It refers to the reaction time of the flue gas and ammonia mixture of the boiler unit in contact with the catalyst, in ms.

[0084] In one embodiment, the calculation correction coefficient k3 can be obtained from a relationship table (Table 4) between the denitration differential pressure and time of the boiler unit and the calculation correction coefficient k3, which is obtained by summarizing relevant data of the long-term use of the boiler unit.

[0085] The time effect test includes: making the flue gas flow through the catalyst of the denitrification device and the ammonia gas sprayed by the ammonia spraying device to perform denitrification treatment, and obtaining the actual denitrification efficiency of the denitrification device; taking the reaction time t of the ammonia gas contacting the catalyst as the reaction time t i The denitration time-efficiency relationship diagram is obtained by taking the efficiency of the denitration device corresponding to the temperature of the time-impact test as the horizontal axis and the efficiency of the denitration device corresponding to the temperature of the time-impact test as the vertical axis.

[0086] In a preferred embodiment, the catalyst differential pressure of the boiler unit and the contact time t i The relationship table of denitration differential pressure and time of boiler unit and calculation correction coefficient k3 (Table 4) is shown in Table 4. Specifically, the first calculation correction coefficient k is obtained according to the catalyst differential pressure. 31 , according to the contact time t i Get the second calculation correction coefficient k 32 ; By comparing the first calculated correction coefficient k31 and the second calculation correction coefficient k 32 The calculation correction coefficient with the largest value among the three is the calculation correction coefficient k3.

[0087] The calculation method of the volume V of the catalyst in the denitrification device 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 inlet of the denitrification device is brought into dC A S / dA=γ N / F can be used to obtain the catalyst surface area, or the NO concentration at the inlet of the denitrification device can be brought into dC N B / dA=γ A / F can be used to obtain the catalyst surface area, thereby obtaining the actual size of the catalyst; where A refers to the catalyst surface area, m 2 ; F refers to the gas phase flow rate, m 3 / s;C N B Refers to the NO concentration at the inlet of the denitrification device, mol / m 3 ; C A S Refers to the NH3 concentration at the input of the denitrification device; γ N is the consumption rate of NO in the denitrification reaction, mol / m 2 ·s;γ A is the consumption rate of NH3 in the denitrification reaction, mol / m 2 ·s.

[0088] The concentration of NO in the main gas phase is γ N The concentration of NH3 in the main gas phase inlet γ is calculated by formula 6-1. A Calculated by formula 6-2:

[0089]

[0090]

[0091] Among them, K fN Refers to the NO interfacial mass transfer coefficient, m / s; K fA Refers to the NH3 interfacial mass transfer coefficient, m / s.

[0092] In one embodiment, the concentration of nitrogen oxides in the flue gas obtained after treatment with a denitrification device is related to catalyst performance. In this embodiment, V2O5 / TiO2 vanadium-based catalysts with V2O5 contents of 1.4, 3.0, 4.5, and 6.6 weight percent were prepared, and each of these catalysts was tested under the same conditions to generate a catalyst component efficiency relationship diagram. Based on this catalyst component efficiency relationship diagram, the following conclusion can be drawn: When the V2O5 content in the catalyst is between 1.4 and 4.5 weight percent, the catalytic efficiency increases with increasing V2O5 content, and the denitrification efficiency improves. However, when the V2O5 content exceeds 6.6 weight percent, the catalytic efficiency decreases. This is primarily due to the different distribution of V2O5 on the TiO2 carrier. When the V2O5 content is between 1.4 and 4.5 weight percent, the V2O5 is evenly distributed on the TiO2 carrier and exists in an equiaxed, vanadium-based form. When the V2O5 content is above 6.6%, V2O5 forms new V2O5 crystallization areas on the carrier TiO2, thereby reducing the catalyst activity.

[0093] In this embodiment, V2O5 is the active component of the catalyst reaction, which converts NO in the flue gas into X It is reduced to N2 and H2O and can also oxidize SO2 in flue gas to SO3. Therefore, in industrial applications, V2O5 content is relatively low. Adding a co-catalyst, WO3 or MoO3, is recommended. WO3 in larger amounts plays both a catalytic and structural role in the catalyst, increasing the temperature range of the catalyst's active reaction and improving its mechanical structure and crystal properties. Trace arsenic, produced in coal combustion, can poison the catalyst, leading to its loss of activity. MoO3 exhibits excellent tolerance to arsenic-induced poisoning.

[0094] In one embodiment, the impact 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, volume loss and / or effective volume loss are unavoidable during operation of the boiler unit. When this occurs, the denitration reaction is less effective, and the nitrogen oxide emission concentration V0 of the boiler unit increases accordingly.

[0095] In one embodiment, the impact contribution value V4 is calculated by formula 7:

[0096] V4=(V 线 -V 保 )×(M′1 / M1+M′2 / M2+M′3 / M3), Equation 7

[0097] Where: M1' refers to the effective volume loss of the first layer of catalyst of the boiler unit, unit is m 3; M1 refers to the effective volume of the first layer of catalyst of the boiler unit when it is new, in m 3 ; M2' refers to the effective volume loss of the second layer catalyst of the boiler unit, in m 3 ; M2 refers to the effective volume of the second layer of catalyst of the boiler unit when it is new, in m 3 ; M3' refers to the effective volume loss of the third layer catalyst of the boiler unit, in m 3 ; M3 refers to the effective volume of the third layer of catalyst of the boiler unit when it is new, in m 3 ; The calculation correction coefficient k4 is obtained based on the total effective volume loss ratio of the three-layer catalyst.

[0098] In one embodiment, the catalyst in the boiler unit described in the present disclosure is stacked in three layers, namely a first layer of catalyst, a second layer of catalyst, and a third layer of catalyst, wherein the third layer of catalyst is arranged downstream of the second layer of catalyst, and the second layer of catalyst is arranged downstream of the first layer of catalyst. In this embodiment, the effective volume loss of each layer of catalyst is related to the continuous operation time T. The effective volume loss ratio of the first layer of catalyst, the second layer of catalyst, and the third layer of catalyst can be obtained respectively based on the relationship table of the effective volume loss ratio of the three-layer catalyst and the continuous operation time (Table 5).

[0099] In one embodiment, the calculation correction coefficient k4 is obtained based on the total effective volume loss percentage of the three-layer catalyst, where the total effective volume loss percentage of the three-layer catalyst is the sum of the effective volume loss percentage of the first layer catalyst, the effective volume loss percentage of the second layer catalyst, and the effective volume loss percentage of the third layer catalyst. The specific value of the calculation correction coefficient k4 is obtained from the relationship table between the total effective volume loss percentage of the catalyst of the boiler unit and the calculation correction coefficient k4 (Table 6).

[0100] In one embodiment, when the effective volume loss of the three-layer catalyst accounts for more than 10% of the total volume, the catalyst in the boiler unit can be regenerated or shut down for repair.

[0101] In one embodiment, the impact 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 regulated by the ammonia injection condition of the ammonia injection device.

[0102] In one embodiment, the impact contribution value V5 is calculated by Formula 8:

[0103] V5=(V 线 -V 保 )×(1-Q1 / Q0)×(1-η1 / η 设 ), Equation 8

[0104] Where: Q1 refers to the actual ammonia injection amount of the denitrification device in the boiler unit, m 3 / s; Q0 refers to the theoretical ammonia injection amount of the denitrification device in the boiler unit, m 3 / s; η1 refers to the actual denitrification efficiency of the boiler unit, in %; η 设 It refers to the designed denitrification efficiency of the boiler unit, in %.

[0105] In one embodiment, the calculation correction coefficient k5 is obtained according to the ammonia injection condition of the boiler unit, wherein the ammonia injection condition 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 an under-injection ammonia state, and the calculation correction coefficient k5 at this time is relatively large, ranging from 1.050 to 1.300; when the value of (Q1-Q0) / Q0 is between -5% and 5%, it indicates that the boiler unit is in a normal ammonia injection state, and the calculation correction coefficient k5 at this time is moderate, specifically 1.000; when the value of (Q1-Q0) / Q0 is greater than 5%, it indicates that the boiler unit is in an over-injection ammonia state, and the calculation correction coefficient k5 at this time is relatively small, specifically 0.800 to 0.950.

[0106] In a specific implementation manner, the specific value of the calculation correction coefficient k5 is obtained according to the relationship table (Table 7) between the ammonia nitrogen molar ratio of the boiler unit and the calculation correction coefficient k5.

[0107] In one embodiment, the annual shutdown and maintenance plan of the boiler unit is scheduled in advance before the whole year of operation, and the shutdown time T 检 Set to more than 168 hours. During the operation of the boiler unit throughout the year, there will be a situation where the unit is shut down for maintenance due to an accident. The downtime is T 事 In addition, the actual continuous operation time T of the boiler unit in a whole year 实际 =8762-T 事 -T 检 .

[0108] In one embodiment, the boiler unit includes unit 1 and unit 2, the continuous operation time of unit 1 is T1, and the continuous operation time of unit 2 is T2; then, the power generation utilization hours T of unit 1 are obtained according to the continuous operation time T1 and the continuous operation time T2. 1运 and the number of hours of power generation utilization of Unit 2, T 2运 In this embodiment, the number of hours of power generation utilization of unit 1 is T 1运 and the number of hours of power generation utilization of Unit 2, T 2运Refers to the full-load operation time of the generator set within one year; when Unit 1 or Unit 2 is operating at full load within one year, the continuous operation time of Unit 1 is T1, which is the power generation utilization hours T 1运 The continuous operation time of unit 2 is T2, which is the number of hours of power generation utilization T 2运 When Unit 1 or Unit 2 operates at low load during the one-year operation period, the average power of Unit 1 or Unit 2 during the one-year operation period is calculated based on the statistical data of the boiler unit power changes over the years. The power generation utilization hours T of the boiler unit are obtained by multiplying the continuous operation time T1 of Unit 1 by the average power. 1运 The power generation utilization hours T of the boiler unit can be obtained by multiplying the continuous operation time T2 of unit 2 by the average power. 2运 .

[0109] In one embodiment, the total nitrogen oxide emission allocation Q of the boiler unit is determined based on the total nitrogen oxide emission of the entire plant issued by the Ecological Environment Bureau through the pollution discharge permit. 总 The total nitrogen oxide emissions allocations 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:

[0110]

[0111]

[0112] In one embodiment, as the operation time of the boiler unit gradually increases, the nitrogen oxide emissions of the boiler unit gradually increase, that is, the nitrogen oxide emission allocation usage of the boiler unit Q y Gradually increasing, among which, the amount of nitrogen oxide emissions allocated is Q y Calculated by formula 10-3:

[0113] Q y =Q 烟气 ×V 排放 ×η 脱硝 , Formula 10-3

[0114] Where Q 烟气 Refers to the total amount of flue gas emissions from the boiler unit, V 排放 refers to the measured average concentration of nitrogen oxides in the boiler unit, η 脱硝 Refers to the average denitrification efficiency of the boiler unit.

[0115] In a specific embodiment, the nitrogen oxide emission allocation usage of unit 1 is calculated by formula 10-4, and the nitrogen oxide emission allocation usage of unit 2 is calculated by formula 10-5:

[0116] Q 1y =Q 烟气1 ×V 排放1 ×η 脱硝1 , Formula 10-4

[0117] Q 2y =Q 烟气2 ×V 排放2 ×η 脱硝2 , Formula 10-5

[0118] Where Q 烟气1 Refers to the total amount of flue gas emissions from Unit 1, V 排放1 is the measured average concentration of nitrogen oxides of Unit 1, η 脱硝1 It refers to the average denitrification efficiency of Unit 1; Q 烟气2 Refers to the total flue gas emissions of Unit 2, V 排放2 is the measured average concentration of nitrogen oxides of Unit 2, η 脱硝2 It refers to the average denitrification efficiency of Unit 2.

[0119] In one embodiment, the impact contribution value V6 and the calculation correction coefficient k6 are related to the nitrogen oxide emission distribution surplus Q of the boiler unit. 剩 Regarding, the impact contribution value V6 is calculated by formula 9:

[0120] V6=(V 线 -V 保 )×(1-Q 剩 / Q 总 ), Equation 9

[0121] Where: Q 剩 It refers to the residual amount of nitrogen oxide emissions allocated by the boiler unit, in t / a; Q 总 Refers to the total amount of nitrogen oxide emissions allocated to the boiler unit Q 总 , unit is t / a.

[0122] In one embodiment, the nitrogen oxide emission distribution surplus Q of the boiler unit is 剩 Calculated by formula 10:

[0123] Q 剩 =Q 总 -Q y , Equation 10

[0124] Where Q yRefers to the allocated usage of nitrogen oxide emissions from the boiler unit.

[0125] In one embodiment, the remaining amount Q is allocated according to the nitrogen oxide emissions of the boiler unit. 剩 The total amount of nitrogen oxide emissions allocated to the boiler unit Q 总 The ratio of the calculated correction coefficient k6 is obtained; in this embodiment, when Q 剩 / Q 总 When the ratio is above 0.667, it means that the total amount of nitrogen oxide emissions allocated to the boiler unit is relatively large. At this time, there is no need to restrict nitrogen oxide emissions from the boiler unit, and the impact on the boiler unit is relatively small. When Q 剩 / Q 总 When the ratio of Q decreases gradually, it means that the total amount of nitrogen oxide emissions allocated to the boiler unit is 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; when Q 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, and the alarm and accident handling procedures are triggered to force the boiler unit to shut down.

[0126] In a specific embodiment, the specific value of the calculated correction coefficient k6 can be obtained based on the relationship table (Table 8) between the nitrogen oxide emission distribution surplus of the boiler unit and the calculated correction coefficient k6, which is obtained by summarizing the relevant data of the long-term use of the boiler unit.

[0127] In one embodiment, Tables 1 to 8 described in the present disclosure are obtained through data analysis and processing based on the long-term operating data of the boiler units of the power plant and various tests.

[0128] A second aspect of the present disclosure provides a method for determining and processing an online nitrogen oxide emission concentration deviation, the method comprising:

[0129] S3. The computer control module obtains the online nitrogen oxide emission concentration V0 according to the calculation method described in the first aspect, and the online nitrogen oxide emission concentration V0 is subjected to deviation judgment by the deviation judgment module. When the online 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 / Nm 3 ; preferably 20 to 45 mg / Nm 3 ;

[0130] S4. When the deviation processing module receives the alarm signal sent by the deviation judgment module, it enables the computer control module to perform deviation processing.

[0131] Through the above-mentioned implementation mode, the computer control module and the deviation judgment module determine whether a deviation occurs in the online nitrogen oxide emission concentration, and perform deviation processing if a deviation occurs. When a deviation occurs in the online nitrogen oxide emission concentration of the boiler unit, the cause of the deviation can be quickly indicated, thereby ensuring the economy of the boiler unit operation while avoiding excessive emissions from the boiler unit.

[0132] In one embodiment, the boiler unit of the present disclosure includes a computing master control system, a deviation judgment processing device and a computer control module.

[0133] In one embodiment, the deviation judgment and processing device includes a deviation judgment module and a deviation processing module; wherein the deviation judgment module is used to pre-implant the national emission standards, ultra-low emission standards, enterprise emission standards, total environmental emission of the unit, parameters and control ranges provided by the equipment manufacturer, etc. in the module. When the V0 calculation result exceeds the control range, an alarm is issued. It is used to compare, screen and check all parameters involved in the calculation, find out the cause of the off-line alarm and send it to the processing module. The deviation processing module is used to receive the alarm information issued by the deviation judgment module, and send the signal for program processing according to the degree of over-limit to the computer control module. If the computer control module cannot process online, a shutdown alarm or offline processing alarm information is issued.

[0134] In one embodiment, a computer control module includes a storage medium, a memory, and a processor. The medium is a non-transitory computer-readable storage medium storing a computing program. The memory stores the computing program; and the processor is configured to execute the computing program in the memory to implement the computing program in the storage medium and / or the memory.

[0135] In one embodiment, the deviation processing described in the present disclosure includes:

[0136] The computer control module compares the numerical values ​​of the influence levels k1V1, k2V2, k3V3, k4V4, k5V5, and k6V6, and sets the influence levels 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 descending order of numerical values;

[0137] When the impact level k6V6 is the first processing item, the computer control module allocates the total amount of nitrogen oxide emissions Q from the machine 临机总 Make adjustments until the alarm signal is eliminated;

[0138] The total amount of nitrogen oxide emissions allocated at the time of operation Q 临机总When the allocation index threshold is not met, the computer control module blocks the value of k6V6 and continues to calculate according to Formula 2; or, the control mode of the boiler unit is switched to manual control.

[0139] In one embodiment, the absolute values ​​of the influence levels (k1V1, k2V2, k3V3, k4V4, k5V5, and k6V6) are compared, and the influencing factors corresponding to the one or two influence levels with the largest absolute values ​​are the causes of the deviation, for example:

[0140] a. When the absolute value of k1V1 is the largest, it indicates that the deviation is caused by abnormal denitration reaction temperature. The upper limit of the denitration reaction temperature in this boiler unit is 420°C, the lower limit of the denitration reaction temperature is 300°C, and the minimum continuous operation temperature of denitration is 290°C.

[0141] b. When the absolute value of k2V2 is the largest, it indicates that the cause of the deviation is abnormal boiler combustion and / or changes in coal quality;

[0142] c. When the absolute value of k3V3 is the largest, it indicates that the cause of the deviation is an abnormality in the denitrification device of the boiler unit;

[0143] d. When the absolute value of k4V4 is the largest, it indicates that the cause of the deviation is the loss of the effective volume of the denitration catalyst of the boiler unit;

[0144] e. When the absolute value of k5V5 is the largest, it indicates that the cause of the deviation is abnormal ammonia injection from the boiler unit;

[0145] f. When the absolute value of k6V6 is the largest, it indicates that the deviation is caused by the emission restriction of the total amount of nitrogen oxides of the boiler unit.

[0146] In one embodiment, the boiler unit used in the present disclosure can be controlled in both automatic and manual modes. Automatic control is provided by a master computing control system. When the online nitrogen oxide emission concentration V0 falls outside the control range, the calculated result exceeds the limit, and the master computing control system issues an over-limit alarm.

[0147] In one embodiment, step S4 further includes:

[0148] The computer control module compares the absolute values ​​of the influence levels k1V1, k2V2, k3V3, k4V4, k5V5, and k6V6, and sets the influence levels 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 descending order of absolute value;

[0149] When the impact level k6V6 is the first processing item, the computer control module allocates the total amount of nitrogen oxide emissions Q from the machine 临机总 Make adjustments until the alarm signal is eliminated;

[0150] The total amount of nitrogen oxide emissions allocated at the time of operation Q 临机总 When the allocation index threshold is not met, the computer control module blocks the value of k6V6 and continues to calculate according to formula 2; or, the control mode of the boiler unit is switched to manual control. 临机总 Failure to meet the allocation index threshold means that the remaining amount of nitrogen oxide emission allocation of adjacent boiler units cannot meet the amount required for the nitrogen oxide emission allocation of the boiler unit.

[0151] In one embodiment, when the computing master control system issues an over-limit alarm, the computing master control system will analyze and determine the factors with the greatest impact (k1V1, k2V2, k3V3, k4V4, k5V5 and k6V6); and perform processing based on the analyzed and determined impact factors to eliminate the alarm signal.

[0152] In this embodiment, when the impact degree k6V6 is the first processing item, the computer master control system determines that the alarm signal is caused by the emission restriction index of the total amount of nitrogen oxides. First, the computer master control system can automatically make reasonable adjustments from the emission restriction index of the total amount of nitrogen oxides of the temporary machine until the over-limit alarm is eliminated; if the emission restriction index of the total amount of nitrogen oxides of the temporary machine is insufficient, the computer master control system can shield k6V6 in Formula 2 and recalculate. If the calculation result after shielding is within the control range, the boiler unit is still in automatic control operation until the computer master control system does not issue an alarm signal, and the shielding item is restored; if the over-limit alarm cannot be eliminated, the automatic control is switched to manual control, and the nitrogen oxide emission lower limit is 35mg / Nm 3 If the total amount of nitrogen oxides is still insufficient, the upper limit of nitrogen oxide emissions shall be 50mg / Nm 3 Run; if the total amount of nitrogen oxides still cannot be controlled, apply for shutdown treatment.

[0153] In a specific embodiment, when the system issues an alarm, the processing method is as follows: the calculation program will analyze and determine the item with the largest impact contribution value. If the remaining amount of environmental protection emissions has the largest impact, the computer will adjust from the temporary environmental protection emission total amount index to reduce the impact of insufficient environmental protection emission total amount. If the temporary environmental protection emission total amount index is also insufficient and the index adjustment cannot be performed, the processing method is as follows: release the automatic state of the machine (manual control), eliminate the alarm, and monitor and control the operation according to the program calculation result value. Maintain the automatic state, internally shield or eliminate the item with the largest impact contribution, and continue to run automatically according to the formula calculation value.

[0154] In a specific implementation, when a negative number appears in the calculation result, the following processing method is used: the calculation program will analyze and determine the item with the largest impact on the contribution value. If the remaining amount of environmental protection emissions has the greatest impact, the computer will adjust from the total environmental protection emission index of the temporary machine to reduce the impact of insufficient total environmental protection emissions. If the total environmental protection emission index of the temporary machine is also insufficient and the index cannot be adjusted, the processing method is as follows: release the automatic state of the machine (manual control), eliminate the alarm, and press the ultra-low emission limit of 35mg / Nm 3 Monitor and control the operation. If 35mg / Nm 3 If the system calculates the total amount of nitrogen oxide emissions and it is still insufficient, it must reduce the denitrification efficiency and operate under control. Alternatively, it can remain in automatic mode, internally shield or remove the most influential contribution item, and continue to operate automatically according to the calculated value.

[0155] In one embodiment, when the impact degree k1V1, k2V2, k3V3, k4V4 or k5V5 is the first processing item, the computer master control system can be made to shield k1V1, k2V2, k3V3, k4V4 or k5V5 in Formula 2 and recalculate. If the calculation result after shielding is within the control range, the boiler unit is still in automatic control operation until the computer master control system does not issue an alarm signal, and the shielding item is restored; if the over-limit alarm cannot be eliminated, the automatic control is switched to manual control, and the nitrogen oxide emission lower limit is 35mg / Nm 3 If the total amount of nitrogen oxides is still insufficient, the upper limit of nitrogen oxide emissions shall be 50mg / Nm 3 Run; if the online nitrogen oxide emission concentration V0 still cannot be controlled within the control range, apply for shutdown processing.

[0156] The present disclosure is further illustrated by the following examples, but the present disclosure is not subject to any limitation. The model of the boiler unit used in the present disclosure is manufactured by Shanghai Boiler Factory. The catalyst used in the present disclosure is a V2O5 / TiO2 vanadium-based catalyst purchased from Corning, Denmark Topsoe, Chongqing Yuanda, Wuxi Longyuan, Japan Hitachi and other companies. The relationship between the calculation correction coefficient K and the performance attenuation parameter Φ and the continuous operation time T of the boiler unit is shown in Table 1; the relationship between the denitrification reaction temperature and the calculation correction coefficient k1 is shown in Table 2; the relationship between boiler combustion and coal quality changes and the calculation correction coefficient k2 is shown in Table 3; the relationship between the denitrification differential pressure and time of the boiler unit and the calculation correction coefficient k3 is shown in Table 4; the relationship between the effective volume loss ratio of the three-layer catalyst and the continuous operation time is shown in Table 5; the relationship between the total effective volume loss ratio of the catalyst of the boiler unit and the calculation correction coefficient k4 is shown in Table 6; the relationship between the ammonia nitrogen molar ratio of the boiler unit and the calculation correction coefficient k5 is shown in Table 7; the relationship between the nitrogen oxide emission distribution residual amount of the boiler unit and the calculation correction coefficient k6 is shown in Table 8.

[0157] Table 1 Relationship between the calculated correction coefficient K and performance attenuation parameter Φ and the continuous operation time T of the boiler unit

[0158] time K Φ 2000h and below 0.8 0.0001 2000<T≤5000h 0.80＜K≤0.85 0.0001-0.0002 5000<T≤8000h 0.85＜K≤0.90 0.0002-0.0003 8000<T≤12000h 0.90＜K≤0.95 0.0003-0.0004 12000<T≤15000h 0.95＜K≤1.00 0.0004-0.0005 15000<T≤18000h 1.00＜K≤1.10 0.0005-0.0006 18000<T≤20000h 1.10＜K≤1.30 0.0006-0.0007 20000<T≤24000h 1.30＜K≤1.50 0.0007-0.0008 More than 24000h 1.50＜K≤2.00 0.0008-0.0009

[0159] Table 2 Relationship between denitrification reaction temperature and calculation correction coefficient k1

[0160]

[0161] Table 3 Relationship between boiler combustion and coal quality changes and calculation correction coefficient k2

[0162]

[0163]

[0164] Table 4 Relationship between denitrification differential pressure and time of boiler unit and calculation correction coefficient k3

[0165]

[0166] Table 5 Relationship between the effective volume loss ratio of the three-layer catalyst and the continuous operation time T of the boiler unit

[0167]

[0168] Table 6 Relationship between the total effective volume loss ratio of catalyst in boiler units and the calculation correction coefficient k4

[0169]

[0170] Table 7 Relationship between the ammonia nitrogen molar ratio of boiler units and the calculation correction coefficient k5

[0171]

[0172] Table 8 Relationship between the remaining amount of nitrogen oxide emissions allocated to boiler units and the calculation correction factor k6

[0173] Judgment conditions <![CDATA[k6]]> <![CDATA[Q 剩 / Q 总 ≥0.667]]> 0 <![CDATA[0.200≤Q 剩 / Q 总 <0.667]]> 1.500 <![CDATA[Q 剩 / Q 总 <0.200]]> 2.000 <![CDATA[Q 剩 / Q 总 =0]]> ∞(trigger alarm and accident handling procedures)

[0174] Example 1

[0175] The boiler units used in Example 1 include Unit 1 and Unit 2; known conditions: boiler factory nitrogen oxide performance guarantee value V 保 200mg / Nm 3The optimal reaction temperature of the catalyst is 310°C, the minimum continuous allowable reaction temperature is 290°C, and the maximum operating reaction temperature is 410°C. The denitrification efficiency is designed to be 85%. Based on the emission volume of the pollutant discharge permit approved by the Ecological and Environmental Protection Bureau, the total nitrogen oxide emission allocation Q for the two million-kilowatt units in the plant is obtained. 总 960 tons / year; Unit 1 power generation utilization hours T 1运 4300 hours; Unit 2 was shut down for 500 hours, and the number of hours of power generation utilization of Unit 2 is T 2运 The NO X Total allocation = (960 × 4300) / (4300 + 4800) = 453 tons / year, NO2 of unit 2 X Total allocated = 507 tons / year.

[0176] Methods for judging faults during continuous operation of boiler units include:

[0177] The operating state is divided into normal operating state and special operating state according to the continuous operating time T of the boiler unit; when T≤2000h, it means that the boiler unit is in normal operating state; when T>2000h, it means that the boiler unit is in special operating state;

[0178] Calculating the continuous operation nitrogen oxide emission concentration V0 of the boiler unit according to the operating status of the boiler unit;

[0179] When the boiler unit is in the normal operating state, the continuous operation nitrogen oxide emission concentration V0 of the boiler unit is calculated using formula 1, and the unit is mg / Nm 3 :

[0180] V0=35-KTΦ, Formula 1

[0181] When the boiler unit is in the special operating state, the continuous operation nitrogen oxide emission concentration V0 of the boiler unit is calculated using formula 2, in mg / Nm 3 :

[0182] V0=35-[KTΦ+(k1V1+k2V2+k3V3+k4V4+k5V5+k6V6)], Formula 2

[0183] Wherein, the performance attenuation parameter Φ and the calculation correction coefficient K are obtained according to Table 1;

[0184] The correction coefficient k1 is calculated according to Table 2, and the impact contribution value V1 is calculated by Formula 3:

[0185] V1=(V 线 -V 保)×(1-T1 / T0), Equation 3;

[0186] The correction coefficient k2 is calculated according to Table 3, and the impact contribution value V2 is calculated by Formula 4:

[0187]

[0188] The correction coefficient k3 is calculated according to Table 4, and the impact contribution value V3 is calculated by Formula 5 and Formula 6:

[0189]

[0190] T i =V / Q, Equation 6;

[0191] The correction coefficient k4 is calculated based on Table 5 and Table 6, and the impact contribution value V4 is calculated using Formula 7:

[0192] V4=(V 线 -V 保 )×(M′1 / M1+M′2 / M2+M′3 / M3), Equation 7;

[0193] The correction coefficient k5 is calculated according to Table 7, and the impact contribution value V5 is calculated by formula 8:

[0194] V5=(V 线 -V 保 )×(1-Q1 / Q0)×(1-η1 / η 设 ), Equation 8;

[0195] The correction coefficient k6 is calculated according to Table 8, and the impact contribution value V5 is calculated using Equations 9 and 10:

[0196] V6=(V 线 -V 保 )×(1-Q 剩 / Q 总 ), Equation 9

[0197] Q 剩 =Q 总 -Q y , Equation 10.

[0198] The following calculations take Unit 1 as an example. The specific calculations are as follows:

[0199] 1. When the boiler unit runs for 0 hours, according to Table 1, K is 0.8 and Φ is 0.0001:

[0200] V0=35-KTΦ=35-0.8×0×0.0001mg / Nm 3 =35mg / Nm 3 ;

[0201] 2. When the boiler unit runs for 1000 hours, according to Table 1, K is 0.8 and Φ is 0.0001:

[0202] V0=35-KTΦ=35-0.8×1000×0.0001mg / Nm 3 =34.92mg / Nm 3 ;

[0203] 3. When the boiler unit runs for 2000 hours, according to Table 1, K is 0.8 and Φ is 0.0001:

[0204] V0=35-KTΦ=35-0.8×2000×0.0001mg / Nm 3 =34.84mg / Nm 3 ;

[0205] 4. When the boiler unit runs for 2500h, according to Table 1, K is 0.825, Φ is 0.00015, where V 线 180mg / Nm 3 , the denitration reaction temperature is 300℃. According to Table 2, when the denitration reaction temperature T1 is 300℃, the corresponding k1 is 0.958:

[0206] k1V1=0.958×(180-200)×(1-300 / 310)=-0.618mg / Nm 3 ;

[0207] Coal type parameter N ar实 0.72%, N ar设 0.71%, T 实 1640℃, T 燃烧 is 1650℃, the oxygen content of air is 4.5%; 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 the oxygen content of air is 4.5% 23 is 1.000, according to k 21 、k 22 and k 23 Comparison shows that k2 is 1.000:

[0208]

[0209] The online denitration efficiency η1 is 80%, and the denitration efficiency η2 corresponding to 62 milliseconds is 75%. According to Table 4, the online catalyst differential pressure P1 is 350 kPa, and the design differential pressure P0 is 500 kPa. Since (P1-P0) / P0=-30%<-5%, k 31 is 0.950; the unit boiler flue gas volume Q is 2100000Nm 3 / h=583m 3 / s, the catalyst supply volume is 365m 3 , calculate t i is 62 milliseconds, so k 32 is 1.050; by comparing k 31 and k 32 It can be seen that k3 is 1.050;

[0210]

[0211] According to Table 5, the effective volume loss ratio of the first layer catalyst is 0.15%, the effective volume loss ratio of the second layer catalyst is 0.1%, and the effective volume loss ratio of the third layer catalyst is 0; according to Table 6,

[0212] The effective volume loss of the three-layer catalyst accounts for less than 1% of the total volume, and the k4 value is 1.1;

[0213] k4V4=1.1×(180-200)×(0.15%+0.1%+0)=-0.055mg / Nm 3 ;

[0214] Q1 is 380 kg / h, Q0 is 420 kg / h, η1 is 80% and η 设 is 85%. According to Table 7, (Q1-Q0) / Q0=-9.5%, k5 is 1.05.

[0215]

[0216] The Q1 of the No. 1 unit is 453 tons / year, and the 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;

[0217] k6V6=0×(180-200)×(1-355 / 453)=0mg / Nm 3 ;

[0218] V0=35-[0.825×2500×0.00015+(-0.618+2.078+0.509-0.055-0.118+0)]=32.89

[0219] 5mg / Nm 3 .

[0220] 5. When the boiler unit runs for 8000 hours, according to Table 1, K is 0.9, Φ is 0.0003, where V 线 230mg / Nm 3 , the denitration reaction temperature is 305℃. According to Table 2, when the denitration reaction temperature T1 is 305℃, the corresponding k1 is 0.978:

[0221] k1V1=0.978×(230-200)×(1-305 / 310)=0.473mg / Nm 3 ;

[0222] Coal type parameter N ar实 0.73%, N ar设 0.71%, T 实 1660℃, T 燃烧 is 1650℃, α is 5.3%; According to Table 3, (N ar实 -N ar设 ) / N ar设 =2.8%, k 21 1.000, T 实 -T 燃烧 =10℃, k 22 k is 1.000 and α is 5.3% 23 is 1.150, according to k 21 、k 22 and k 23 Comparison shows that k2 is 1.150:

[0223]

[0224] The online denitrification efficiency η1 is 82%, and the denitrification efficiency η2 corresponding to 58 milliseconds is 70%. According to Table 4, the online catalyst differential pressure P1 is 510 kPa, and the design differential pressure P0 is 500 kPa. Since (P1-P0) / P0=-2%, k 31 is 1.000; the unit boiler flue gas volume Q is 2250000Nm 3 / h=625m 3 / s, the catalyst supply volume is 365m 3 , calculate t i is 58 milliseconds, so k 32 is 1.050; by comparing k31 and k 32 It can be seen that k3 is 1.050;

[0225]

[0226] According to Table 5, the effective volume loss ratio of the first layer catalyst is 0.8%, the effective volume loss ratio of the second layer catalyst is 0.4%, and the effective volume loss ratio of the third layer catalyst is 0.1; according to Table 6, the total effective volume loss ratio of the three layers of catalyst is 1.3%, and the value of k4 is 1.3;

[0227] k4V4=1.3×(230-200)×(0.8%+0.4%+0.1%)=0.507mg / Nm 3 ;

[0228] Q1 is 410 kg / h, Q0 is 420 kg / h, η1 is 82% and η 设 is 85%. According to Table 7, (Q1-Q0) / Q0=-2.3%, k5 is 1.05.

[0229]

[0230] The Q1 of the No. 1 unit is 453 tons / year, and the 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 2;

[0231] k6V6=2×(230-200)×(1-87.14 / 453)=48.458mg / Nm 3 ;

[0232] V0=35-[0.9×8000×0.0003+(0.473-3.014-0.764+0.507+0.026+48.453)]=-12.

[0233] 841mg / Nm.

[0234] 6. When the boiler unit runs for 15000h, according to Table 1, K is 1.0, Φ is 0.0005, where V 线 195mg / Nm 3 , the denitration reaction temperature is 295℃. According to Table 2, when the denitration reaction temperature T1 is 295℃, the corresponding k1 is 0.925:

[0235] k1V1=0.925×(195-200)×(1-295 / 310)=-0.224mg / Nm 3 ;

[0236] Coal type parameter N ar实 0.70%, N ar设 0.71%, T 实 1650℃, T 燃烧 is 1650℃, α is 5.5%; 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 is 1.000 and α is 5.5% 23 is 1.150, according to k 21 、k 22 and k 23 After comparison, we take the maximum value and get k2 as 1.150:

[0237]

[0238] The online denitration efficiency η1 is 87%, and the denitration efficiency η2 corresponding to 66 milliseconds is 76%. According to Table 4, the online catalyst differential pressure P1 is 510 kPa, and the design differential pressure P0 is 500 kPa. Since (P1-P0) / P0=24%, k 31 is 1.050; the unit boiler flue gas volume Q is 1980000Nm 3 / h=550m 3 / s, the catalyst supply volume is 365m 3 , calculate t i is 66 milliseconds, so k 32 is 1.050; by comparing k 31 and k 32 It can be seen that k3 is 1.050;

[0239]

[0240] According to Table 5, the effective volume loss ratio of the first layer catalyst is 1.8%, the effective volume loss ratio of the second layer catalyst is 1.0%, and the effective volume loss ratio of the third layer catalyst is 0.5; according to Table 6, the total effective volume loss ratio of the three layers of catalyst is 3.3%, and the value of k4 is 2;

[0241] k4V4=2.0×(195-200)×(1.8%+1.0%+0.5%)=-0.33mg / Nm 3;

[0242] Q1 is 425 kg / h, Q0 is 420 kg / h, η1 is 82% and η 设 is 85%. From Table 7, we can see that (Q1-Q0) / Q0=1.1%, and k5 is 1.0.

[0243]

[0244] After 15,000 hours of operation, the total amount of nitrogen oxides of Unit 1 will be the same as the total amount issued by the Environmental Protection Bureau in the second year. It needs to be calculated in sections, that is, the continuous operation time in the second year is 15,000-8763=6237h. Similarly, according to Q1=453 tons / year, the calculated Q 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 1.5;

[0245]

[0246] V0=35-[1.0×15000×0.0005+(-0.224+0.108+0.372-0.33+0.002-4.722)]=32.2

[0247] 94mg / Nm.

[0248] 7. When the boiler unit runs for 25,000 hours, according to Table 1, K is 1.6, Φ is 0.00085, where V 线 140mg / Nm 3 , the denitration reaction temperature is 290℃. According to Table 2, when the denitration reaction temperature T1 is 290℃, the corresponding k1 is 0.884:

[0249] k1V1=0.884×(140-200)×(1-290 / 310)=-3.422mg / Nm 3 ;

[0250] Coal type parameter N ar实 0.70%, N ar设 0.71%, T 实 1610℃, T 燃烧 is 1650℃, α is 3.0%; According to Table 3, (N ar实 -N ar设 ) / N ar设 <0%, k 21 0.95, T 实 -T 燃烧 =-40℃, k22 k is 0.850 and α is 3.0% 23 is 0.850, according to k 21 、k 22 and k 23 After comparison, we take the maximum value and get k2 as 0.950:

[0251]

[0252] The online denitration efficiency η1 is 85%, and the denitration efficiency η2 corresponding to 66 milliseconds is 76%. According to Table 4, the online catalyst differential pressure P1 is 530 kPa, and the design differential pressure P0 is 500 kPa. Since (P1-P0) / P0=6%, k 31 is 1.050; the unit boiler flue gas volume Q is 1980000Nm 3 / h=550m 3 / s, the catalyst supply volume is 365m 3 , calculate t i is 66 milliseconds, so k 32 is 1.050; by comparing k 31 and k 32 It can be seen that k3 is 1.050;

[0253]

[0254] According to Table 5, the effective volume loss ratio of the first layer catalyst is 5.5%, the effective volume loss ratio of the second layer catalyst is 3.5%, and the effective volume loss ratio of the third layer catalyst is 1.2; according to Table 6, the total effective volume loss ratio of the three layers of catalyst is 10.2%, and the value of k4 is 10;

[0255] k4V4=10×(140-200)×(5.5%+3.5%+1.2%)=-61.2mg / Nm 3 ;

[0256] Q1 is 460kg / h, Q0 is 420kg / h, η1 is 85% and η 设 is 85%. From Table 7, we can see that (Q1-Q0) / Q0=0, and k5 is 0.95.

[0257]

[0258] After 25,000 hours of operation, the total amount of nitrogen oxides of Unit 1 will take over the total amount issued by the Environmental Protection Bureau in the third year, and needs to be calculated in sections, that is, the continuous operation time in the third year is 25,000-8763×2=7474h. Similarly, according to Q1=453 tons / year, the calculated Q 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;

[0259]

[0260] V0=35-[1.6×25000×0.00085+(-3.422+7.660+1.827-61.200+0-67.91)]=124.0

[0261] 45mg / Nm 3 .

[0262] S3. According to the fault phenomenon when the continuous operation time of the boiler unit is 8000h and 25000h respectively, the specific ones are:

[0263] When the boiler unit has been running continuously for 8000 hours, the calculated result is a negative value. After comparing the absolute values ​​of k1V1, k2V2, k3V3, k4V4, k5V5 and k6V6, it can be seen that the absolute value of k6V6 (48.458) is the largest. Therefore, it can be concluded that the cause of the fault is insufficient total nitrogen oxide emissions from all units in the plant.

[0264] When the boiler unit runs continuously for 25,000 hours, the calculated result is 124.045 mg / Nm 3 Greater than 35mg / Nm 3 By comparing the absolute values ​​of k1V1, k2V2, k3V3, k4V4, k5V5 and k6V6, it can be seen that the absolute value of k6V6 (67.91) is the largest. Therefore, it can be seen that the cause of the fault is the insufficient total amount of nitrogen oxide emissions from the units in the whole plant.

[0265] According to the data analysis in the embodiment, it can be seen that the method disclosed herein compares the calculation results under normal working conditions and special working conditions. From the data, when the continuous operation time of the boiler unit is less than 2000h and 15000h, the calculation results are within the emission standard of 35mg / Nm 3 Below and the difference is not big, it is in normal state; when the boiler unit is in continuous operation time of 8000h and 25000h, the calculated results are consistent with the emission standard of 35mg / Nm 3 A significant deviation occurred. Analysis revealed that the cause of the failure was insufficient total nitrogen oxide emissions from all units in the plant. The disclosed judgment method can accurately reflect the cause of the failure during continuous operation of the boiler unit, thereby preventing the boiler unit from exceeding emission standards while ensuring the economic efficiency of the boiler unit operation.

[0266] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0267] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0268] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for calculating the online nitrogen oxide emission concentration of a boiler unit, characterized in that: The calculation method includes: S1. Determine the current operating state 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 2000 hours, the operating state is a normal operating state; when the continuous operating time T of the boiler unit is greater than 2000 hours, the operating state is a special operating state; S2. Calculating the online nitrogen oxide emission concentration V0 of the boiler unit according to the operating state of the boiler unit; When the boiler unit is in the normal operating state, the online nitrogen oxide emission concentration V0 of the boiler unit is calculated using formula 1, in mg / Nm 3 : , Formula 1 When the boiler unit is in the special operating state, the online nitrogen oxide emission concentration V0 of the boiler unit is calculated using Formula 2, in mg / Nm 3 : , Equation 2 Where: K refers to the calculation correction coefficient of the boiler unit, which is dimensionless; T refers to the continuous operation time of the boiler unit, in hours; Φ refers to the performance attenuation parameter of the boiler unit, in mg / Nm 3 .H; V1 refers to the contribution of the reaction temperature of the catalyst of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm 3 ; k1 refers to the calculation correction coefficient of the catalyst reaction temperature of the boiler unit, dimensionless; V2 refers to the contribution of the combustion of the boiler unit and the change of coal quality to the nitrogen oxide emission concentration of the boiler unit, and the unit is mg / Nm 3 ; k2 refers to the calculation correction coefficient of boiler combustion and coal quality changes of the boiler unit, dimensionless; V3 refers to the contribution of the denitration reaction time of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm 3 ; k3 refers to the calculation correction coefficient of the denitration differential pressure and time of the boiler unit, dimensionless; V4 refers to the contribution of the effective reaction volume of the catalyst of the boiler unit to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm 3 ; k4 refers to the calculation correction coefficient of the effective volume of the catalyst of the boiler unit, 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, in mg / Nm 3 ; k5 refers to the calculation correction coefficient of the ammonia nitrogen molar ratio of the boiler unit, dimensionless; V6 refers to the contribution of the total nitrogen oxide emissions of the entire plant's units to the nitrogen oxide emission concentration of the boiler unit, in mg / Nm 3 ; k6 refers to the calculation correction coefficient for the emission control of the total amount of nitrogen oxides of the boiler unit, which is dimensionless.

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

3. The calculation method according to claim 1, characterized in that The impact contribution value V1 is calculated by formula 3: , Equation 3 Where: V 线 Refers to the online measurement concentration of nitrogen oxides of the boiler unit, in mg / Nm 3 ; V 保 Refers to the guaranteed nitrogen oxide concentration performance value of the boiler unit at the factory, in mg / Nm 3 ; T1 refers to the real-time reaction temperature of the denitration device of the boiler unit, in °C; T0 refers to the optimal reaction temperature of the denitration device of the boiler unit, in °C; The calculation correction coefficient k1 is obtained according to the denitration reaction temperature of the boiler unit.

4. The calculation method according to claim 3, characterized in that The impact contribution value V2 is calculated by formula 4: , Equation 4 Where: N ar实 It refers to the nitrogen content in the actual coal type of the boiler unit, in units of %; N ar设 It refers to the nitrogen content in the design coal type of the boiler unit, in units of %; T 实 It refers to the flame center temperature when the pulverized coal in the furnace of the boiler unit is burning, in degrees Celsius; T 燃烧 It refers to the theoretical flame center temperature of the boiler unit when the pulverized coal is burning in the furnace, in degrees Celsius; α refers to the oxygen content in the air during combustion of pulverized coal in the furnace of the boiler unit, and the unit is %; The calculation correction coefficient k2 is obtained according to the coal type variation parameter, the combustion temperature variation parameter and the air oxygen content α.

5. The calculation method according to claim 3, characterized in that: The impact contribution value V3 is calculated by formula 5: , Equation 5 Where: P1 refers to the actual operating differential pressure of the catalyst of the boiler unit, in kPa; P0 refers to the theoretical operating differential pressure of the catalyst of the boiler unit, in kPa; η1 refers to the actual denitrification efficiency of the boiler unit, in units of %; η2 refers to the reaction time t of the flue gas and ammonia mixture of the boiler unit in contact with the catalyst i The corresponding denitrification efficiency is expressed in%; The calculation correction coefficient k3 is calculated based on the catalyst differential pressure of the boiler unit and the contact time t between the catalyst and the flue gas. i get; The contact time between the catalyst and the flue gas is t i Calculated by formula 6: , Equation 6 Where: Q refers to the actual flue gas volume flowing through the catalyst of the boiler unit, in m 3 / s; V refers to the hollow volume of the catalyst channel of the boiler unit, in m 3 ; t i It refers to the reaction time of the flue gas and ammonia mixture of the boiler unit in contact with the catalyst, in ms.

6. The calculation method according to claim 3, characterized in that: The impact contribution value V4 is calculated by formula 7: , Equation 7 Where: Refers to the effective volume loss of the first layer of catalyst of the boiler unit, in m 3 ; Refers to the effective volume of the first layer of catalyst of the boiler unit when it is new, in m 3 ; Refers to the effective volume loss of the second layer catalyst of the boiler unit, in m 3 ; Refers to the effective volume of the second layer of catalyst of the boiler unit when it is new, in m 3 ; Refers to the effective volume loss of the third layer catalyst of the boiler unit, in m 3 ; Refers to the effective volume of the third layer of catalyst of the boiler unit when it is new, in m 3 ; The calculation correction coefficient k4 is obtained based on the total effective volume loss ratio of the three-layer catalyst.

7. The calculation method according to claim 3, characterized in that: The impact contribution value V5 is calculated by formula 8: , Equation 8 Where: Q1 refers to the actual ammonia injection amount of the denitrification device in the boiler unit, m 3 / s; Q0 refers to the theoretical ammonia injection amount of the denitrification device in the boiler unit, m 3 / s; η1 refers to the actual denitrification efficiency of the boiler unit, in units of %; η 设 It refers to the designed denitrification efficiency of the boiler unit, in units of %; The calculation correction coefficient k5 is obtained according to the ammonia injection amount of the boiler unit.

8. The calculation method according to claim 3, characterized in that: The impact contribution value V6 is calculated by formula 9: , Equation 9 Where: Q 剩 It refers to the residual amount of nitrogen oxide emissions allocated by the boiler unit, in t / a; Q 总 Refers to the total amount of nitrogen oxide emissions allocated to the boiler unit Q 总 , unit is t / a; The nitrogen oxide emission distribution surplus Q of the boiler unit is calculated by formula 10 剩 : , Equation 10 Where Q y Refers to the allocated usage of nitrogen oxide emissions from the boiler unit in question; The calculation correction coefficient k6 is based on the nitrogen oxide emission distribution surplus Q of the boiler unit 剩 The total amount of nitrogen oxide emissions allocated to the boiler unit Q 总 The ratio is worth getting.

9. A method for determining and processing online nitrogen oxide emission concentration deviation, characterized in that: The method includes: S3. The computer control module obtains the online nitrogen oxide emission concentration V0 by the calculation method according to any one of claims 1 to 8, and the online nitrogen oxide emission concentration V0 is subjected to deviation judgment by the deviation judgment module. When the online 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 / Nm 3 ; S4. When the deviation processing module receives the alarm signal sent by the deviation judgment module, it enables the computer control module to perform 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 sets the influence levels 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 descending order of absolute value; When the impact level k6V6 is the first processing item, the computer control module allocates the total amount of nitrogen oxide emissions Q from the machine 临机总 Make adjustments until the alarm signal is eliminated; The total amount of nitrogen oxide emissions allocated at the time of operation Q 临机总 When the allocation index threshold is not met, the computer control module blocks the value of k6V6 and continues to calculate according to Formula 2; or, the control mode of the boiler unit is switched from automatic control to manual control.

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