Determination method and control method for ammonia spraying amount in flue gas denitration

Abstract

The invention provides a flue gas denitration ammonia spraying amount determination method and a flue gas denitration ammonia spraying amount control method. The flue gas denitration ammonia injection amount determination method comprises the following steps: acquiring a flue gas denitration theoretical ammonia supply amount when a denitration reactor outlet reaches a target NOx concentration under a target working condition, and a denitration reactor outlet actually measured NOx concentration curve corresponding to different ammonia injection amounts, a denitration reactor outlet NOx concentration deviation value curve corresponding to different ammonia spraying amounts and a denitration reactor outlet ammonia escape rate curve corresponding to different ammonia spraying amounts; on the basis of a flue gas denitration theoretical ammonia supply amount when a denitration reactor outlet reaches a target NOx concentration under a target working condition, a denitration reactor outlet actually measured NOx concentration curve corresponding to different ammonia spraying amounts, a denitration reactor outlet NOx concentration deviation value curve corresponding to different ammonia spraying amounts, and a denitration reactor outlet ammonia escape rate curve corresponding to different ammonia spraying amounts, a denitration reactor outlet NOx concentration deviation value curve corresponding to different ammonia spraying amounts. And determining the optimal ammonia spraying amount of flue gas denitration when the outlet of the denitration reactor reaches the target NOx concentration under the target working condition.

Description

Technical Field

[0001] The invention belongs to the technical field of flue gas denitrification, and in particular relates to a method for determining and controlling ammonia injection amount for flue gas denitrification. Background Art

[0002] Coal-fired power plants mostly use the selective catalytic reduction process (SCR) to remove NOx from the flue gas at the tail of the boiler. The amount of ammonia sprayed for denitrification and the activity of the denitrification catalyst are the two most important parameters affecting the denitrification efficiency. In the actual denitrification operation, many factors affect the investment rate of denitrification automatic control and the NOx concentration control effect. For example, due to the uneven distribution of NOx concentration at the denitrification outlet, the small number of online measurement points installed and the unrepresentative installation position, the turbulent flow field in the denitrification flue, and the deviation of online instrument measurement, there is a deviation between the actual ammonia supply and the theoretical ammonia supply, causing the NOx concentration to exceed the standard or the ammonia escape to exceed the standard; the detection focuses more on the hourly average of the NOx concentration in the flue gas at the total outlet, while there is a certain time delay between the NOx concentration value at the denitrification outlet and the NOx concentration value at the total outlet, so the adjustment of ammonia spray at the denitrification point cannot effectively affect the NOx concentration at the total outlet in real time. The current control of ammonia injection for denitrification is mostly blindly adjusted according to the NOx concentration value at the denitrification outlet or the NOx concentration value in the chimney. It is a lagging and passive adjustment based on the outlet, lacking scientific, stable and forward-looking control.

[0003] In summary, there is still a need to study a technical solution for controlling the amount of ammonia injection with active regulation and the ability to achieve stable denitrification operation, so as to guide the economic, efficient and environmentally friendly operation of the denitrification system and solve the problems of passivity, lag and blindness in the current denitrification ammonia injection control. Summary of the invention

[0004] The purpose of the present invention is to provide a technical solution for controlling the amount of ammonia injection with active regulation and control and capable of achieving stable denitrification operation, so as to guide the economic, efficient and environmentally friendly operation of the denitrification system and solve the problems of passivity, lag and blindness existing in the current denitrification ammonia injection control.

[0005] In order to achieve the above objectives, the present invention provides the following four technical solutions.

[0006] In a first aspect, the present invention provides a method for determining the amount of ammonia injected for flue gas denitrification, wherein the method comprises:

[0007] Obtain the theoretical ammonia supply for flue gas denitration under target operating conditions to achieve a target NOx concentration at the outlet of the denitration reactor; wherein the target operating conditions refer to the target denitration reactor inlet NOx concentration and the target denitration reactor inlet flue gas volume;

[0008] Obtaining a measured NOx concentration curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts under target operating conditions, a NOx concentration deviation value curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, and an ammonia escape rate curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts; wherein the NOx concentration deviation value at the outlet of the denitration reactor refers to the difference between the measured NOx concentration at the outlet of the denitration reactor and the target NOx concentration;

[0009] Based on the theoretical ammonia supply for flue gas denitrification that achieves the target NOx concentration at the outlet of the denitrification reactor under target operating conditions, the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, the NOx concentration deviation value curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, the optimal ammonia injection amount for flue gas denitrification that achieves the target NOx concentration at the outlet of the denitrification reactor under target operating conditions is determined.

[0010] According to a preferred embodiment of the first aspect, the theoretical ammonia supply for flue gas denitrification is determined by the following formula:

[0011]

[0012] In the formula, Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; is the NOx mass flow rate at the denitration reactor inlet, mg / h; V m is the molar volume of gas under standard conditions, L / mol, usually 22.4L / mol; Theoretical ammonia supply for flue gas denitrification, m 3 / h; n is the molar ratio of ammonia nitrogen, dimensionless; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; Ammonia escape from the denitrification reactor outlet, mg / m 3 , standard state, dry basis, 6% oxygen content; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content.

[0013] According to a preferred embodiment of the first aspect, the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions, the NOx concentration deviation value curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts can be determined based on, but not limited to, data obtained from a denitrification reactor outlet NOx concentration test at different ammonia injection amounts under the target operating conditions, or based on historical flue gas denitrification operation data under the target operating conditions.

[0014] According to a preferred embodiment of the first aspect, based on the theoretical ammonia supply for flue gas denitration to achieve the target NOx concentration at the outlet of the denitration reactor under the target operating conditions, the measured NOx concentration curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, the NOx concentration deviation value curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, determining the optimal ammonia injection amount for flue gas denitration to achieve the target NOx concentration at the outlet of the denitration reactor under the target operating conditions includes:

[0015] Based on the theoretical ammonia supply for flue gas denitration to achieve the target NOx concentration at the outlet of the denitration reactor under target operating conditions, the NOx concentration deviation value curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, the range of ammonia injection amounts that can simultaneously meet the conditions that the absolute value of the NOx deviation value at the outlet of the denitration reactor is ≤ the target NOx concentration at the outlet of the denitration reactor × 20%, the ammonia escape rate at the outlet of the denitration reactor is less than 3ppm, and the absolute value of the difference between the ammonia injection amount and the theoretical ammonia supply amount is ≤ the theoretical ammonia supply amount × 10% is determined as the ammonia injection amount adjustment range under the target operating conditions:

[0016] Within the ammonia injection amount adjustment range under the target operating conditions, determine the ammonia injection amount corresponding to the point with the minimum absolute value of the slope of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions as the optimal ammonia injection amount for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under the target operating conditions;

[0017] More preferably, the slope of the NOx concentration curve measured at the outlet of the denitration reactor corresponding to different ammonia injection amounts under the target operating conditions is determined by the following formula:

[0018]

[0019] Wherein, j is the operating point number of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment interval under the target operating conditions, arranged from small to large according to the ammonia injection amount; n is the total number of operating points of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment interval under the target operating conditions; is the slope of the jth operating point on the denitration reactor outlet measured NOx concentration curve corresponding to different ammonia injection amounts under target operating conditions within the ammonia injection amount adjustment range under target operating conditions; is the measured NOx concentration at the jth operating point on the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment range under the target operating conditions; is the ammonia injection amount corresponding to the jth operating point on the measured NOx concentration curve at the outlet of the denitrification reactor under the target operating conditions and under different ammonia injection amounts within the target operating conditions within the ammonia injection amount adjustment range, m 3 / h.

[0020] In a second aspect, the present invention provides a method for controlling the amount of ammonia sprayed for flue gas denitrification, wherein the method comprises:

[0021] A method for controlling the amount of ammonia sprayed for flue gas denitration provided by an embodiment of the present invention is used to determine the optimal amount of ammonia sprayed for flue gas denitration to achieve a target NOx concentration at the outlet of a denitration reactor under target operating conditions;

[0022] Under the target operating conditions, the optimal ammonia injection amount for flue gas denitration that achieves the target NOx concentration at the outlet of the denitration reactor under the target operating conditions determined in step S21 is used as the initial ammonia injection amount value to perform flue gas denitration; and the measured NOx concentration at the outlet of the denitration reactor is obtained in real time;

[0023] Under the target operating conditions, the ammonia injection amount is adjusted in real time according to the measured NOx concentration at the outlet of the denitrification reactor obtained in real time;

[0024] When the absolute value of the difference between the measured NOx concentration at the outlet of the denitration reactor and the target NOx concentration is ≤ the target NOx concentration at the outlet of the denitration reactor × 10%, the current ammonia injection amount is maintained;

[0025] When the target NOx concentration at the outlet of the denitrification reactor × 10% < the difference between the measured NOx concentration at the outlet of the denitrification reactor and the target NOx concentration ≤ the target NOx concentration at the outlet of the denitrification reactor × 20%, the ammonia injection value is adjusted to the sum of the current ammonia injection value and the first correction value of the ammonia injection value; the first correction value of the ammonia injection value is determined according to the following formula:

[0026]

[0027] In the formula, is to correct the NOx mass flow rate at the inlet of the denitrification reactor, mg / h; Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; Vm is the molar volume of gas under standard conditions, L / mol, usually 22.4L / mol; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; The measured NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; n fb is the corrected ammonia nitrogen molar ratio, dimensionless; is the first correction value of ammonia injection amount, m 3 / h.

[0028] When the negative target NOx concentration at the outlet of the denitrification reactor × 20% ≤ the difference between the measured NOx concentration at the outlet of the denitrification reactor and the target NOx concentration < the negative target NOx concentration at the outlet of the denitrification reactor × 10%, the ammonia injection value is adjusted to the difference between the current ammonia injection value and the second correction value of the ammonia injection value; the second correction value of the ammonia injection value is determined according to the following formula:

[0029]

[0030] In the formula, is to correct the NOx mass flow rate at the inlet of the denitrification reactor, mg / h; Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; V m is the molar volume of gas under standard conditions, L / mol, usually 22.4L / mol; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; The measured NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; n fb2 is the corrected ammonia nitrogen molar ratio, dimensionless; Ammonia escape from the denitrification reactor outlet, mg / m 3 , standard state, dry basis, 6% oxygen content; is the second correction value of ammonia injection amount, m 3 / h.

[0031] In a third aspect, the present invention provides a system for determining the amount of ammonia injection for flue gas denitrification, wherein the system comprises:

[0032] Theoretical ammonia supply acquisition module: used to obtain the theoretical ammonia supply for flue gas denitration under target operating conditions to achieve the target NOx concentration at the outlet of the denitration reactor; wherein the target operating conditions refer to the target denitration reactor inlet NOx concentration and the target denitration reactor inlet flue gas volume;

[0033] Measured data acquisition module: used to obtain the measured NOx concentration curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts under target operating conditions, the NOx concentration deviation value curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts; wherein the NOx concentration deviation value at the outlet of the denitration reactor refers to the difference between the measured NOx concentration at the outlet of the denitration reactor and the target NOx concentration;

[0034] Ammonia injection amount determination module: used to determine the optimal ammonia injection amount for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under target operating conditions based on the theoretical ammonia supply for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under target operating conditions, the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, the NOx concentration deviation value curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts.

[0035] According to a preferred implementation of the third aspect, the theoretical ammonia supply acquisition module determines the theoretical ammonia supply for flue gas denitrification by the following formula:

[0036]

[0037]

[0038] In the formula, Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; is the NOx mass flow rate at the denitration reactor inlet, mg / h; V m is the molar volume of gas under standard conditions, L / mol, usually 22.4L / mol; Theoretical ammonia supply for flue gas denitrification, m 3 / h; n is the molar ratio of ammonia nitrogen, dimensionless; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; Ammonia escape from the denitrification reactor outlet, mg / m 3 , standard state, dry basis, 6% oxygen content; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content.

[0039] According to a preferred implementation of the third aspect, the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions, the NOx concentration deviation value curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts can be determined based on, but not limited to, data obtained from a denitrification reactor outlet NOx concentration test at different ammonia injection amounts under the target operating conditions, or based on historical flue gas denitrification operation data under the target operating conditions.

[0040] According to a preferred embodiment of the third aspect, the ammonia injection amount determination module includes:

[0041] Ammonia injection adjustment range determination submodule: It is used to determine the range of ammonia injection amount that can simultaneously meet the following conditions: the absolute value of the NOx deviation value at the outlet of the denitrification reactor ≤ the target NOx concentration at the outlet of the denitrification reactor × 20%, the ammonia escape rate at the outlet of the denitrification reactor is less than 3ppm, and the absolute value of the difference between the ammonia injection amount and the theoretical ammonia supply amount ≤ the theoretical ammonia supply amount × 10% as the ammonia injection amount adjustment range under the target operating conditions:

[0042] The optimal ammonia injection amount determination submodule is used to determine the ammonia injection amount corresponding to the point with the minimum absolute value of the slope of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment range under the target operating conditions as the optimal ammonia injection amount for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under the target operating conditions;

[0043] More preferably, the slope of the NOx concentration curve measured at the outlet of the denitration reactor corresponding to different ammonia injection amounts under the target operating conditions is determined by the following formula:

[0044]

[0045] Wherein, j is the operating point number of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment interval under the target operating conditions, arranged from small to large according to the ammonia injection amount; n is the total number of operating points of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment interval under the target operating conditions; is the slope of the jth operating point on the denitration reactor outlet measured NOx concentration curve corresponding to different ammonia injection amounts under target operating conditions within the ammonia injection amount adjustment range under target operating conditions; is the measured NOx concentration at the jth operating point on the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment range under the target operating conditions; is the ammonia injection amount corresponding to the jth operating point on the measured NOx concentration curve at the outlet of the denitrification reactor under the target operating conditions and under different ammonia injection amounts within the target operating conditions within the ammonia injection amount adjustment range, m 3 / h.

[0046] In a fourth aspect, the present invention provides a flue gas denitrification ammonia injection control system, wherein the system comprises:

[0047] The third aspect of the present invention provides a system for determining the amount of ammonia sprayed for flue gas denitration: used to determine the optimal amount of ammonia sprayed for flue gas denitration to achieve a target NOx concentration at the outlet of the denitration reactor under target operating conditions;

[0048] A flue gas denitration control unit is used to perform flue gas denitration under target operating conditions, using the optimal ammonia injection amount for flue gas denitration that achieves the target NOx concentration at the outlet of the denitration reactor under the target operating conditions determined in step S21 as the initial ammonia injection amount value; and to obtain the measured NOx concentration at the outlet of the denitration reactor in real time;

[0049] Flue gas denitrification ammonia injection amount adjustment unit: used to adjust the ammonia injection amount in real time according to the actual measured NOx concentration at the outlet of the denitrification reactor obtained in real time under the target operating conditions;

[0050] When the absolute value of the difference between the measured NOx concentration at the outlet of the denitration reactor and the target NOx concentration is ≤ the target NOx concentration at the outlet of the denitration reactor × 10%, the current ammonia injection amount is maintained;

[0051] When the target NOx concentration at the outlet of the denitrification reactor × 10% < the difference between the measured NOx concentration at the outlet of the denitrification reactor and the target NOx concentration ≤ the target NOx concentration at the outlet of the denitrification reactor × 20%, the ammonia injection value is adjusted to the sum of the current ammonia injection value and the first correction value of the ammonia injection value; the first correction value of the ammonia injection value is determined according to the following formula:

[0052]

[0053]

[0054] In the formula, is to correct the NOx mass flow rate at the inlet of the denitrification reactor, mg / h; Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; V m is the molar volume of gas under standard conditions, L / mol, usually 22.4L / mol; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; The measured NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; n fb is the corrected ammonia nitrogen molar ratio, dimensionless; is the first correction value of ammonia injection amount, m 3 / h;

[0055] When the negative target NOx concentration at the outlet of the denitrification reactor × 20% ≤ the difference between the measured NOx concentration at the outlet of the denitrification reactor and the target NOx concentration < the negative target NOx concentration at the outlet of the denitrification reactor × 10%, the ammonia injection value is adjusted to the difference between the current ammonia injection value and the second correction value of the ammonia injection value; the second correction value of the ammonia injection value is determined according to the following formula:

[0056]

[0057] In the formula, is to correct the NOx mass flow rate at the inlet of the denitrification reactor, mg / h; Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; V m is the molar volume of gas under standard conditions, L / mol, usually 22.4L / mol; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; The measured NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; n fb2 is the corrected ammonia nitrogen molar ratio, dimensionless; Ammonia escape from the denitrification reactor outlet, mg / m3 , standard state, dry basis, 6% oxygen content; is the second correction value of ammonia injection amount, m 3 / h.

[0058] In a fifth aspect, the present invention provides a storage medium storing one or more programs, which can be executed by one or more processors to implement the method for determining the amount of ammonia injection for flue gas denitrification provided in the first aspect of the present invention.

[0059] In a sixth aspect, the present invention provides a storage medium storing one or more programs, which can be executed by one or more processors to implement the method for controlling the amount of ammonia injection for flue gas denitrification provided in the second aspect of the present invention.

[0060] In a seventh aspect, the present invention provides a device suitable for carrying out the method for determining the amount of ammonia sprayed for flue gas denitrification provided in the first aspect of the present invention, the device comprising:

[0061] A processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; the memory is used to store computer programs; the processor is used to implement the method for determining the amount of ammonia injection for flue gas denitrification provided by the first aspect of the present invention when executing the program stored in the memory.

[0062] In a seventh aspect, the present invention provides a device suitable for carrying out the method for controlling the amount of ammonia injection for flue gas denitration provided in the second aspect of the present invention, the device comprising:

[0063] A processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; the memory is used to store computer programs; the processor is used to implement the method for controlling the amount of ammonia injection for flue gas denitrification provided in the second aspect of the present invention when executing the program stored in the memory.

[0064] Compared with the prior art, the technical solution provided by the present invention can realize active regulation and stable operation of ammonia injection control to guide the economic, efficient and environmentally friendly operation of the denitrification system, and solve the problems of passivity, lag and blindness in the current denitrification ammonia injection control. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under target operating conditions.

[0066] Figure 2 This is the distribution diagram of the slope of the curve at each operating point of the measured NOx concentration at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under target operating conditions. DETAILED DESCRIPTION

[0067] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0068] An embodiment of the present invention provides a method for determining the amount of ammonia injected for flue gas denitrification, wherein the method comprises:

[0069] Step S1: obtaining the theoretical ammonia supply for flue gas denitration under target operating conditions to achieve a target NOx concentration at the outlet of the denitration reactor; wherein the target operating conditions refer to the target denitration reactor inlet NOx concentration and the target denitration reactor inlet flue gas volume conditions;

[0070] Step S2: Obtaining a measured NOx concentration curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts under target operating conditions, a NOx concentration deviation value curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, and an ammonia escape rate curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts; wherein the NOx concentration deviation value at the outlet of the denitration reactor refers to the difference between the measured NOx concentration at the outlet of the denitration reactor and the target NOx concentration;

[0071] Step S3: Based on the theoretical ammonia supply for flue gas denitrification that achieves the target NOx concentration at the outlet of the denitrification reactor under the target operating conditions, the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, the NOx concentration deviation value curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, the optimal ammonia injection amount for flue gas denitrification that achieves the target NOx concentration at the outlet of the denitrification reactor under the target operating conditions is determined.

[0072] Furthermore, the theoretical ammonia supply for flue gas denitrification is determined by the following formula:

[0073]

[0074] In the formula, Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; is the NOx mass flow rate at the denitration reactor inlet, mg / h; V m is the molar volume of gas under standard conditions, L / mol, usually 22.4L / mol; Theoretical ammonia supply for flue gas denitrification, m 3 / h; n is the molar ratio of ammonia nitrogen, dimensionless; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; Ammonia escape from the denitrification reactor outlet, mg / m 3 , standard state, dry basis, 6% oxygen content; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content.

[0075] Furthermore, the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions, the NOx concentration deviation value curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts can be determined based on, but not limited to, data obtained from a denitrification reactor outlet NOx concentration test at different ammonia injection amounts under the target operating conditions, and based on historical flue gas denitrification operation data under the target operating conditions.

[0076] Furthermore, based on the theoretical ammonia supply for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under the target operating conditions, the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, the NOx concentration deviation value curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, the optimal ammonia injection amount for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under the target operating conditions is determined to include:

[0077] Based on the theoretical ammonia supply for flue gas denitration to achieve the target NOx concentration at the outlet of the denitration reactor under target operating conditions, the NOx concentration deviation value curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, the range of ammonia injection amounts that can simultaneously meet the conditions that the absolute value of the NOx deviation value at the outlet of the denitration reactor is ≤ the target NOx concentration at the outlet of the denitration reactor × 20%, the ammonia escape rate at the outlet of the denitration reactor is less than 3ppm, and the absolute value of the difference between the ammonia injection amount and the theoretical ammonia supply amount is ≤ the theoretical ammonia supply amount × 10% is determined as the ammonia injection amount adjustment range under the target operating conditions:

[0078] Within the ammonia injection amount adjustment range under the target operating conditions, determine the ammonia injection amount corresponding to the point with the minimum absolute value of the slope of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions as the optimal ammonia injection amount for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under the target operating conditions;

[0079] Furthermore, the slope of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions is determined by the following formula:

[0080]

[0081] Wherein, j is the operating point number of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment interval under the target operating conditions, arranged from small to large according to the ammonia injection amount; n is the total number of operating points of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment interval under the target operating conditions; is the slope of the jth operating point on the denitration reactor outlet measured NOx concentration curve corresponding to different ammonia injection amounts under target operating conditions within the ammonia injection amount adjustment range under target operating conditions; is the measured NOx concentration at the jth operating point on the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment range under the target operating conditions; is the ammonia injection amount corresponding to the jth operating point on the measured NOx concentration curve at the outlet of the denitrification reactor under the target operating conditions and under different ammonia injection amounts within the target operating conditions within the ammonia injection amount adjustment range, m 3 / h.

[0082] An embodiment of the present invention provides a method for controlling the amount of ammonia sprayed for flue gas denitration, wherein the method comprises:

[0083] Step S21: using a method for controlling ammonia injection amount for flue gas denitration provided by an embodiment of the present invention to determine an optimal ammonia injection amount for flue gas denitration that achieves a target NOx concentration at the outlet of a denitration reactor under target operating conditions;

[0084] Step S22: Under the target operating conditions, the optimal ammonia injection amount for flue gas denitration that achieves the target NOx concentration at the outlet of the denitration reactor under the target operating conditions determined in step S21 is used as the initial ammonia injection amount value to perform flue gas denitration; and the measured NOx concentration at the outlet of the denitration reactor is obtained in real time;

[0085] Step S23: Under the target operating conditions, the ammonia injection amount is adjusted in real time according to the measured NOx concentration at the outlet of the denitration reactor obtained in real time;

[0086] When the absolute value of the difference between the measured NOx concentration at the outlet of the denitration reactor and the target NOx concentration is ≤ the target NOx concentration at the outlet of the denitration reactor × 10%, the current ammonia injection amount is maintained;

[0087] When the target NOx concentration at the outlet of the denitrification reactor × 10% < the difference between the measured NOx concentration at the outlet of the denitrification reactor and the target NOx concentration ≤ the target NOx concentration at the outlet of the denitrification reactor × 20%, the ammonia injection value is adjusted to the sum of the current ammonia injection value and the first correction value of the ammonia injection value; the first correction value of the ammonia injection value is determined according to the following formula:

[0088]

[0089] In the formula, is to correct the NOx mass flow rate at the inlet of the denitrification reactor, mg / h; Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; V m is the molar volume of gas under standard conditions, L / mol, usually 22.4L / mol; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; The measured NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; n fb is the corrected ammonia nitrogen molar ratio, dimensionless; is the first correction value of ammonia injection amount, m 3 / h.

[0090] When the negative target NOx concentration at the outlet of the denitrification reactor × 20% ≤ the difference between the measured NOx concentration at the outlet of the denitrification reactor and the target NOx concentration < the negative target NOx concentration at the outlet of the denitrification reactor × 10%, the ammonia injection value is adjusted to the difference between the current ammonia injection value and the second correction value of the ammonia injection value; the second correction value of the ammonia injection value is determined according to the following formula:

[0091]

[0092]

[0093] In the formula, is to correct the NOx mass flow rate at the inlet of the denitrification reactor, mg / h; Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; V m is the molar volume of gas under standard conditions, L / mol, usually 22.4L / mol; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; The measured NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; n fb2 is the corrected ammonia nitrogen molar ratio, dimensionless; Ammonia escape from the denitrification reactor outlet, mg / m 3 , standard state, dry basis, 6% oxygen content; is the second correction value of ammonia injection amount, m 3 / h.

[0094] An embodiment of the present invention provides a system for determining the amount of ammonia sprayed for flue gas denitration, which can implement the method for determining the amount of ammonia sprayed for flue gas denitration provided in the above embodiment. The system includes:

[0095] Theoretical ammonia supply acquisition module 31: used to obtain the theoretical ammonia supply for flue gas denitration under target operating conditions to achieve the target NOx concentration at the outlet of the denitration reactor; wherein the target operating conditions refer to the target denitration reactor inlet NOx concentration and the target denitration reactor inlet flue gas volume;

[0096] The measured data acquisition module 32 is used to obtain the measured NOx concentration curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts under the target operating conditions, the NOx concentration deviation value curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts; wherein the NOx concentration deviation value at the outlet of the denitration reactor refers to the difference between the measured NOx concentration at the outlet of the denitration reactor and the target NOx concentration;

[0097] Ammonia injection amount determination module 33: is used to determine the optimal ammonia injection amount for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under the target operating conditions based on the theoretical ammonia supply for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under the target operating conditions, the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, the NOx concentration deviation value curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts.

[0098] Furthermore, the theoretical ammonia supply acquisition module 31 determines the theoretical ammonia supply for flue gas denitrification by the following formula:

[0099]

[0100]

[0101] In the formula, Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; is the NOx mass flow rate at the denitration reactor inlet, mg / h; V m is the molar volume of gas under standard conditions, L / mol, usually 22.4L / mol; Theoretical ammonia supply for flue gas denitrification, m 3 / h; n is the molar ratio of ammonia nitrogen, dimensionless; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; Ammonia escape from the denitrification reactor outlet, mg / m 3 , standard state, dry basis, 6% oxygen content; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content.

[0102] Furthermore, the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions, the NOx concentration deviation value curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts can be determined based on, but not limited to, data obtained from a denitrification reactor outlet NOx concentration test at different ammonia injection amounts under the target operating conditions, and based on historical flue gas denitrification operation data under the target operating conditions.

[0103] Further, the ammonia injection amount determination module 33 includes:

[0104] Ammonia injection amount adjustment interval determination submodule 331: used to determine the range of ammonia injection amount that can simultaneously meet the following conditions: the absolute value of the NOx deviation value at the outlet of the denitrification reactor ≤ the target NOx concentration at the outlet of the denitrification reactor × 20%, the ammonia escape rate at the outlet of the denitrification reactor is less than 3ppm, and the absolute value of the difference between the ammonia injection amount and the theoretical ammonia supply amount ≤ the theoretical ammonia supply amount × 10% as the ammonia injection amount adjustment interval under the target operating condition based on the flue gas denitrification theoretical ammonia supply amount that achieves the target NOx concentration at the outlet of the denitrification reactor under the target operating condition, the NOx concentration deviation value curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, as the ammonia injection amount adjustment interval under the target operating condition:

[0105] The optimal ammonia injection amount determination submodule 332 is used to determine, within the ammonia injection amount adjustment range under the target operating condition, the ammonia injection amount corresponding to the point with the minimum absolute value of the slope of the measured NOx concentration curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts under the target operating condition as the optimal ammonia injection amount for flue gas denitration to achieve the target NOx concentration at the outlet of the denitration reactor under the target operating condition;

[0106] Furthermore, the slope of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions is determined by the following formula:

[0107]

[0108] Wherein, j is the operating point number of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment interval under the target operating conditions, arranged from small to large according to the ammonia injection amount; n is the total number of operating points of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment interval under the target operating conditions; is the slope of the jth operating point on the denitration reactor outlet measured NOx concentration curve corresponding to different ammonia injection amounts under target operating conditions within the ammonia injection amount adjustment range under target operating conditions; is the measured NOx concentration at the jth operating point on the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment range under the target operating conditions; is the ammonia injection amount corresponding to the jth operating point on the measured NOx concentration curve at the outlet of the denitrification reactor under the target operating conditions and under different ammonia injection amounts within the target operating conditions within the ammonia injection amount adjustment range, m 3 / h.

[0109] An embodiment of the present invention provides a flue gas denitration ammonia injection control system, which can implement the flue gas denitration ammonia injection control method provided in the above embodiment, and the system includes:

[0110] The system for determining the amount of ammonia injection for flue gas denitration provided in the above embodiment is used to determine the optimal amount of ammonia injection for flue gas denitration to achieve a target NOx concentration at the outlet of the denitration reactor under target operating conditions;

[0111] A flue gas denitration control unit is used to perform flue gas denitration under target operating conditions, using the optimal ammonia injection amount for flue gas denitration that achieves the target NOx concentration at the outlet of the denitration reactor under the target operating conditions determined in step S21 as the initial ammonia injection amount value; and to obtain the measured NOx concentration at the outlet of the denitration reactor in real time;

[0112] Flue gas denitrification ammonia injection amount adjustment unit: used to adjust the ammonia injection amount in real time according to the actual measured NOx concentration at the outlet of the denitrification reactor obtained in real time under the target operating conditions;

[0113] When the absolute value of the difference between the measured NOx concentration at the outlet of the denitration reactor and the target NOx concentration is ≤ the target NOx concentration at the outlet of the denitration reactor × 10%, the current ammonia injection amount is maintained;

[0114] When the target NOx concentration at the outlet of the denitrification reactor × 10% < the difference between the measured NOx concentration at the outlet of the denitrification reactor and the target NOx concentration ≤ the target NOx concentration at the outlet of the denitrification reactor × 20%, the ammonia injection value is adjusted to the sum of the current ammonia injection value and the first correction value of the ammonia injection value; the first correction value of the ammonia injection value is determined according to the following formula:

[0115]

[0116]

[0117] In the formula, is to correct the NOx mass flow rate at the inlet of the denitrification reactor, mg / h; Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; V m is the molar volume of gas under standard conditions, L / mol, usually 22.4L / mol; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; The measured NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; n fb is the corrected ammonia nitrogen molar ratio, dimensionless; is the first correction value of ammonia injection amount, m 3 / h.

[0118] When the negative target NOx concentration at the outlet of the denitrification reactor × 20% ≤ the difference between the measured NOx concentration at the outlet of the denitrification reactor and the target NOx concentration < the negative target NOx concentration at the outlet of the denitrification reactor × 10%, the ammonia injection value is adjusted to the difference between the current ammonia injection value and the second correction value of the ammonia injection value; the second correction value of the ammonia injection value is determined according to the following formula:

[0119]

[0120] In the formula, is to correct the NOx mass flow rate at the inlet of the denitrification reactor, mg / h; Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3, standard state, dry basis, 6% oxygen content; V m is the molar volume of gas under standard conditions, L / mol, usually 22.4L / mol; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; The measured NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; n fb2 is the corrected ammonia nitrogen molar ratio, dimensionless; Ammonia escape from the denitrification reactor outlet, mg / m 3 , standard state, dry basis, 6% oxygen content; is the second correction value of ammonia injection amount, m 3 / h.

[0121] The embodiment of the present invention also provides a storage medium. The storage medium stores one or more programs. The storage medium may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a read-only memory, a flash memory, a hard disk or a solid-state drive; the memory may also include a combination of the above-mentioned types of memory.

[0122] When one or more programs in the storage medium can be executed by one or more processors to implement the steps of the above-mentioned method for determining the amount of ammonia injection for flue gas denitrification, please refer to the above-mentioned embodiment of the method for determining the amount of ammonia injection for flue gas denitrification for details, which will not be repeated here.

[0123] The embodiment of the present invention also provides a storage medium. The storage medium stores one or more programs. The storage medium may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a read-only memory, a flash memory, a hard disk or a solid-state drive; the memory may also include a combination of the above-mentioned types of memory.

[0124] When one or more programs in the storage medium can be executed by one or more processors to implement the steps of the above-mentioned flue gas denitrification ammonia injection amount control method, please refer to the above-mentioned flue gas denitrification ammonia injection amount control method embodiment for details, which will not be repeated here.

[0125] An embodiment of the present invention provides a device for determining the amount of ammonia injection for flue gas denitrification, the device comprising: a processor communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus;

[0126] Memory, used to store computer programs;

[0127] The processor is used to execute the program stored in the memory to implement the steps of the above-mentioned method for determining the amount of ammonia injection for flue gas denitrification. For the specific steps of the method, please refer to the above-mentioned embodiment of the method for determining the amount of ammonia injection for flue gas denitrification, which will not be repeated here.

[0128] An embodiment of the present invention provides a flue gas denitrification ammonia injection control device, the device comprising: a processor communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus;

[0129] Memory, used to store computer programs;

[0130] The processor is used to execute the program stored in the memory to implement the steps of the above-mentioned flue gas denitrification ammonia injection control method. For the specific steps of the method, please refer to the above-mentioned flue gas denitrification ammonia injection control method embodiment, which will not be repeated here.

[0131] Example 1

[0132] This embodiment takes a unit at full load as an example for illustration. The NOx concentration at the inlet of the denitrification reactor is 250 mg / m 3 (standard state, dry basis, 6% O2), flue gas volume is 1200000m 3 / h (standard state, dry basis, 6% O2), the NOx control concentration at the outlet of the denitrification reactor is 30m 3 / h (standard state, dry basis, 6% O2), ammonia escape at the outlet of denitrification reactor 1.52mg / m 3 (standard state, dry basis, 6% O2), the outlet of the denitrification reactor is a single-point sampling mode. Specifically, this embodiment determines the amount of ammonia injection by the following flue gas denitrification ammonia injection determination method and controls the amount of ammonia injection by the following flue gas denitrification ammonia injection control method.

[0133] Methods for determining the amount of ammonia injected for flue gas denitrification include:

[0134] 1. Obtain the theoretical ammonia supply for flue gas denitration under target operating conditions to achieve the target NOx concentration at the outlet of the denitration reactor; wherein the target operating conditions refer to the target denitration reactor inlet NOx concentration and the target denitration reactor inlet flue gas volume;

[0135] The theoretical ammonia supply for flue gas denitrification is determined by the following formula:

[0136]

[0137] In the formula, Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; is the NOx mass flow rate at the denitration reactor inlet, mg / h; V m is the molar volume of gas under standard conditions, L / mol, which is 22.4 L / mol in this embodiment; Theoretical ammonia supply for flue gas denitrification, m 3 / h; n is the molar ratio of ammonia nitrogen, dimensionless; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; Ammonia escape from the denitrification reactor outlet, mg / m 3 , standard state, dry basis, 6% oxygen content; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content;

[0138] Theoretical ammonia supply for flue gas denitrification in this embodiment 129.1m 3 / h.

[0139] 2. Based on the historical operation data of flue gas denitrification under the target operating conditions, determine the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions (such as Figure 1 As shown), the NOx concentration deviation value curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts and the ammonia escape rate curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts; wherein the NOx concentration deviation value at the outlet of the denitrification reactor refers to the difference between the actually measured NOx concentration at the outlet of the denitrification reactor and the target NOx concentration.

[0140] 3. Based on the theoretical ammonia supply for flue gas denitration to achieve the target NOx concentration at the outlet of the denitration reactor under the target operating conditions, the NOx concentration deviation value curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, determine the range of ammonia injection amounts that can simultaneously meet the conditions that the absolute value of the NOx deviation value at the outlet of the denitration reactor is ≤ the target NOx concentration at the outlet of the denitration reactor × 20%, the ammonia escape rate at the outlet of the denitration reactor is less than 3ppm, and the absolute value of the difference between the ammonia injection amount and the theoretical ammonia supply amount is ≤ the theoretical ammonia supply amount × 10% as the ammonia injection amount adjustment range under the target operating conditions:

[0141] Within the ammonia injection amount adjustment range under the target operating conditions, determine the ammonia injection amount corresponding to the point with the minimum absolute value of the slope of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions as the optimal ammonia injection amount for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under the target operating conditions;

[0142] Among them, the slope of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions is determined by the following formula:

[0143]

[0144] Wherein, j is the operating point number of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment interval under the target operating conditions, arranged from small to large according to the ammonia injection amount; n is the total number of operating points of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment interval under the target operating conditions; is the slope of the jth operating point on the denitration reactor outlet measured NOx concentration curve corresponding to different ammonia injection amounts under target operating conditions within the ammonia injection amount adjustment range under target operating conditions; is the measured NOx concentration at the jth operating point on the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment range under the target operating conditions; is the ammonia injection amount corresponding to the jth operating point on the measured NOx concentration curve at the outlet of the denitrification reactor under the target operating conditions and under different ammonia injection amounts within the target operating conditions within the ammonia injection amount adjustment range, m 3 / h;

[0145] The ammonia injection adjustment range under the target working condition is [120m 3 / h,142m 3 / h]; within the ammonia injection adjustment range under the target operating conditions, the slope distribution of the curves of the measured NOx concentration at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions is as follows: Figure 2 As shown in the figure, the optimal ammonia injection rate for flue gas denitration to achieve the target NOx concentration at the outlet of the denitration reactor under the target operating conditions is 133m 3 / h.

[0146] A method for controlling the amount of ammonia sprayed for flue gas denitrification, wherein the method comprises:

[0147] A. Using a flue gas denitration ammonia injection control method provided in this embodiment to determine the optimal flue gas denitration ammonia injection amount to achieve the target NOx concentration at the outlet of the denitration reactor under target operating conditions; specifically, 133m 3 / h.

[0148] B. Under the target operating conditions, the optimal ammonia injection amount for flue gas denitrification that achieves the target NOx concentration at the outlet of the denitrification reactor under the target operating conditions determined in step S21 is used as the initial ammonia injection amount value to perform flue gas denitrification; and the actual measured NOx concentration at the outlet of the denitrification reactor is obtained in real time.

[0149] C. Under the target operating conditions, the ammonia injection amount is regulated in real time according to the measured NOx concentration at the outlet of the denitrification reactor obtained in real time;

[0150] When the absolute value of the difference between the measured NOx concentration at the outlet of the denitration reactor and the target NOx concentration is ≤ the target NOx concentration at the outlet of the denitration reactor × 10%, the current ammonia injection amount is maintained;

[0151] When the target NOx concentration at the outlet of the denitrification reactor × 10% < the difference between the measured NOx concentration at the outlet of the denitrification reactor and the target NOx concentration ≤ the target NOx concentration at the outlet of the denitrification reactor × 20%, the ammonia injection value is adjusted to the sum of the current ammonia injection value and the first correction value of the ammonia injection value; the first correction value of the ammonia injection value is determined according to the following formula:

[0152]

[0153] In the formula, is to correct the NOx mass flow rate at the inlet of the denitrification reactor, mg / h; Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; V m is the molar volume of gas under standard conditions, L / mol, usually 22.4L / mol; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; The measured NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; n fb is the corrected ammonia nitrogen molar ratio, dimensionless; is the first correction value of ammonia injection amount, m 3 / h.

[0154] When the negative target NOx concentration at the outlet of the denitrification reactor × 20% ≤ the difference between the measured NOx concentration at the outlet of the denitrification reactor and the target NOx concentration < the negative target NOx concentration at the outlet of the denitrification reactor × 10%, the ammonia injection value is adjusted to the difference between the current ammonia injection value and the second correction value of the ammonia injection value; the second correction value of the ammonia injection value is determined according to the following formula:

[0155]

[0156] In the formula, is to correct the NOx mass flow rate at the inlet of the denitrification reactor, mg / h; Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; V m is the molar volume of gas under standard conditions, L / mol, usually 22.4L / mol; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; The measured NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; n fb2 is the corrected ammonia nitrogen molar ratio, dimensionless; Ammonia escape from the denitrification reactor outlet, mg / m 3 , standard state, dry basis, 6% oxygen content; is the second correction value of ammonia injection amount, m 3 / h;

[0157] Based on the real-time measured NOx concentration at the outlet of the denitrification reactor, the difference between the measured NOx concentration at the outlet of the denitrification reactor and the target NOx concentration was maintained at 1.6 mg / m 3 When the absolute value of the difference between the measured NOx concentration at the outlet of the denitrification reactor and the target NOx concentration is ≤ the target NOx concentration at the outlet of the denitrification reactor × 10%, the current ammonia injection amount is maintained, that is, the optimal ammonia injection amount for flue gas denitrification to reach the target NOx concentration at the outlet of the denitrification reactor under the target operating conditions is 133m 3 / h.

[0158] The preferred embodiments of the present invention are described above. Many features and advantages of these embodiments are clear from this detailed description, and therefore the claims are intended to cover all such features and advantages of these embodiments that fall within their true spirit and scope. In addition, since many modifications and changes are readily apparent to those skilled in the art, it is not intended to limit the embodiments of the present invention to the precise structure and operation illustrated and described, but all suitable modifications and equivalents that fall within its scope may be included.

Claims

1. A method for determining the amount of ammonia sprayed for flue gas denitrification, wherein: The method includes: Obtain the theoretical ammonia supply for flue gas denitration under target operating conditions to achieve a target NOx concentration at the outlet of the denitration reactor; wherein the target operating conditions refer to the target denitration reactor inlet NOx concentration and the target denitration reactor inlet flue gas volume; Obtaining a measured NOx concentration curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts under target operating conditions, a NOx concentration deviation value curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, and an ammonia escape rate curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts; wherein the NOx concentration deviation value at the outlet of the denitration reactor refers to the difference between the measured NOx concentration at the outlet of the denitration reactor and the target NOx concentration; Based on the theoretical ammonia supply for flue gas denitrification that achieves the target NOx concentration at the outlet of the denitrification reactor under target operating conditions, the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, the NOx concentration deviation value curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, the optimal ammonia injection amount for flue gas denitrification that achieves the target NOx concentration at the outlet of the denitrification reactor under target operating conditions is determined.

2. The method according to claim 1, wherein: The theoretical ammonia supply for flue gas denitrification is determined by the following formula: In the formula, Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; is the NOx mass flow rate at the denitration reactor inlet, mg / h; V m is the molar volume of gas under standard conditions, L / mol; Theoretical ammonia supply for flue gas denitrification, m 3 / h; n is the molar ratio of ammonia nitrogen, dimensionless; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; Ammonia escape from the denitrification reactor outlet, mg / m 3 , standard state, dry basis, 6% oxygen content; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content.

3. The method according to claim 1, wherein: Based on the theoretical ammonia supply for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under target operating conditions, the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, the NOx concentration deviation value curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, the optimal ammonia injection amount for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under target operating conditions is determined, including: Based on the theoretical ammonia supply for flue gas denitration to achieve the target NOx concentration at the outlet of the denitration reactor under target operating conditions, the NOx concentration deviation value curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, the range of ammonia injection amounts that can simultaneously meet the conditions that the absolute value of the NOx deviation value at the outlet of the denitration reactor is ≤ the target NOx concentration at the outlet of the denitration reactor × 20%, the ammonia escape rate at the outlet of the denitration reactor is less than 3ppm, and the absolute value of the difference between the ammonia injection amount and the theoretical ammonia supply amount is ≤ the theoretical ammonia supply amount × 10% is determined as the ammonia injection amount adjustment range under the target operating conditions: Within the ammonia injection adjustment range under the target operating conditions, the ammonia injection amount corresponding to the point with the smallest absolute value of the slope of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions is determined as the optimal ammonia injection amount for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under the target operating conditions.

4. The method according to claim 3, wherein: The slope of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions is determined by the following formula: Wherein, j is the operating point number of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment interval under the target operating conditions, arranged from small to large according to the ammonia injection amount; n is the total number of operating points of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment interval under the target operating conditions; is the slope of the jth operating point on the denitration reactor outlet measured NOx concentration curve corresponding to different ammonia injection amounts under target operating conditions within the ammonia injection amount adjustment range under target operating conditions; is the measured NOx concentration at the jth operating point on the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment range under the target operating conditions; is the ammonia injection amount corresponding to the jth operating point on the measured NOx concentration curve at the outlet of the denitrification reactor under the target operating conditions and under different ammonia injection amounts within the target operating conditions within the ammonia injection amount adjustment range, m 3 / h.

5. A method for controlling the amount of ammonia sprayed for flue gas denitrification, wherein: The method includes: Determine the optimal ammonia injection amount for flue gas denitration to achieve a target NOx concentration at the outlet of the denitration reactor under target operating conditions using a flue gas denitration ammonia injection amount control method according to any one of claims 1 to 4; Under the target operating conditions, the optimal ammonia injection amount for flue gas denitration that achieves the target NOx concentration at the outlet of the denitration reactor under the target operating conditions determined in step S21 is used as the initial ammonia injection amount value to perform flue gas denitration; and the measured NOx concentration at the outlet of the denitration reactor is obtained in real time; Under the target operating conditions, the ammonia injection amount is adjusted in real time according to the measured NOx concentration at the outlet of the denitrification reactor obtained in real time; When the absolute value of the difference between the measured NOx concentration at the outlet of the denitration reactor and the target NOx concentration is ≤ the target NOx concentration at the outlet of the denitration reactor × 10%, the current ammonia injection amount is maintained; When the target NOx concentration at the outlet of the denitrification reactor × 10% < the difference between the measured NOx concentration at the outlet of the denitrification reactor and the target NOx concentration ≤ the target NOx concentration at the outlet of the denitrification reactor × 20%, the ammonia injection value is adjusted to the sum of the current ammonia injection value and the first correction value of the ammonia injection value; the first correction value of the ammonia injection value is determined according to the following formula: In the formula, is to correct the NOx mass flow rate at the inlet of the denitrification reactor, mg / h; Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; V m is the molar volume of gas under standard conditions, L / mol; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; The measured NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; n fb is the corrected ammonia nitrogen molar ratio, dimensionless; is the first correction value of ammonia injection amount, m 3 / h; When the negative target NOx concentration at the outlet of the denitrification reactor × 20% ≤ the difference between the measured NOx concentration at the outlet of the denitrification reactor and the target NOx concentration < the negative target NOx concentration at the outlet of the denitrification reactor × 10%, the ammonia injection value is adjusted to the difference between the current ammonia injection value and the second correction value of the ammonia injection value; the second correction value of the ammonia injection value is determined according to the following formula: In the formula, is to correct the NOx mass flow rate at the inlet of the denitrification reactor, mg / h; Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; V m is the molar volume of gas under standard conditions, L / mol; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; The measured NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; n fb2 is the corrected ammonia nitrogen molar ratio, dimensionless; Ammonia escape from the denitrification reactor outlet, mg / m 3 , standard state, dry basis, 6% oxygen content; is the second correction value of ammonia injection amount, m 3 / h.

6. A system for determining the amount of ammonia sprayed for flue gas denitrification, wherein: The system includes: Theoretical ammonia supply acquisition module: used to obtain the theoretical ammonia supply for flue gas denitration under target operating conditions to achieve the target NOx concentration at the outlet of the denitration reactor; wherein the target operating conditions refer to the target denitration reactor inlet NOx concentration and the target denitration reactor inlet flue gas volume; Measured data acquisition module: used to obtain the measured NOx concentration curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts under target operating conditions, the NOx concentration deviation value curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitration reactor corresponding to different ammonia injection amounts; wherein the NOx concentration deviation value at the outlet of the denitration reactor refers to the difference between the measured NOx concentration at the outlet of the denitration reactor and the target NOx concentration; Ammonia injection amount determination module: used to determine the optimal ammonia injection amount for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under target operating conditions based on the theoretical ammonia supply for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under target operating conditions, the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, the NOx concentration deviation value curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts, and the ammonia escape rate curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts.

7. The system according to claim 6, wherein: The theoretical ammonia supply acquisition module determines the theoretical ammonia supply for flue gas denitrification through the following formula: In the formula, Q sn is the flue gas volume at the inlet of the denitrification reactor, m 3 / h, standard state, dry basis, 6% oxygen content; is the NOx concentration at the inlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content; is the NOx mass flow rate at the denitration reactor inlet, mg / h; V m is the molar volume of gas under standard conditions, L / mol; Theoretical ammonia supply for flue gas denitrification, m 3 / h; n is the molar ratio of ammonia nitrogen, dimensionless; is the molar mass of NOx, g / mol; is the molar mass of NH3, g / mol; Ammonia escape from the denitrification reactor outlet, mg / m 3 , standard state, dry basis, 6% oxygen content; is the target NOx concentration at the outlet of the denitrification reactor, mg / m 3 , standard state, dry basis, 6% oxygen content.

8. The system according to claim 6, wherein: The ammonia injection amount determination module includes: Ammonia injection adjustment range determination submodule: It is used to determine the range of ammonia injection amount that can simultaneously meet the following conditions: the absolute value of the NOx deviation value at the outlet of the denitrification reactor ≤ the target NOx concentration at the outlet of the denitrification reactor × 20%, the ammonia escape rate at the outlet of the denitrification reactor is less than 3ppm, and the absolute value of the difference between the ammonia injection amount and the theoretical ammonia supply amount ≤ the theoretical ammonia supply amount × 10% as the ammonia injection amount adjustment range under the target operating conditions: Optimal ammonia injection amount determination submodule: used to determine the ammonia injection amount corresponding to the point with the smallest absolute value of the slope of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment range under the target operating conditions as the optimal ammonia injection amount for flue gas denitrification to achieve the target NOx concentration at the outlet of the denitrification reactor under the target operating conditions.

9. The system according to claim 8, wherein: The slope of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions is determined by the following formula: Wherein, j is the operating point number of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment interval under the target operating conditions, arranged from small to large according to the ammonia injection amount; n is the total number of operating points of the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment interval under the target operating conditions; is the slope of the jth operating point on the denitration reactor outlet measured NOx concentration curve corresponding to different ammonia injection amounts under target operating conditions within the ammonia injection amount adjustment range under target operating conditions; is the measured NOx concentration at the jth operating point on the measured NOx concentration curve at the outlet of the denitrification reactor corresponding to different ammonia injection amounts under the target operating conditions within the ammonia injection amount adjustment range under the target operating conditions; is the ammonia injection amount corresponding to the jth operating point on the measured NOx concentration curve at the outlet of the denitrification reactor under the target operating conditions and under different ammonia injection amounts within the target operating conditions within the ammonia injection amount adjustment range, m 3 / h.

10. A storage medium, wherein: The storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the method for determining the amount of ammonia injection for flue gas denitrification according to any one of claims 1-4.

11. A storage medium, wherein: The storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the method for controlling the amount of ammonia injection for flue gas denitrification according to claim 5.

12. A device for determining the amount of ammonia sprayed for flue gas denitrification, the device comprising: Processor communication interface, memory and communication bus, wherein the processor, communication interface and memory communicate with each other via the communication bus; Memory, used to store computer programs; The processor is used to execute the program stored in the memory to implement the method for determining the amount of ammonia injection for flue gas denitrification according to any one of claims 1 to 4.

13. A flue gas denitrification ammonia injection control device, the device comprising: Processor communication interface, memory and communication bus, wherein the processor, communication interface and memory communicate with each other via the communication bus; Memory, used to store computer programs; The processor is used to execute the program stored in the memory to implement the flue gas denitrification ammonia injection amount control method as described in claim 5.

Images