Fuel gas-steam combined cycle flue gas denitration optimal operation method

Abstract

The invention relates to the technical field of energy-saving and emission-reducing power generation equipment, in particular to a fuel gas-steam combined cycle flue gas denitration optimal operation method which comprises the following steps: acquiring a typical peak regulation working condition of a unit; ignition time is determined, and generator grid connection time is determined; acquiring an environment temperature, and determining an average warm-up load; the exhaust gas temperature is obtained, the average warming-up load is corrected, and the current warming-up load of the gas turbine is adjusted to the average warming-up load; establishing a curve graph of the emission concentration value changing along with time, and adjusting the current warming-up load; the inlet temperature of the denitration system is obtained, the inlet temperature change rate of the denitration system is calculated, and the catalyst input time is determined. By adjusting the unit starting time, the unit warming-up load value and the denitration system input parameters, a reasonable unit starting optimization strategy is provided, the nitrogen oxide emission amount and the concentration of NO2 in flue gas are reduced, the nitrogen oxide emission amount of the combined cycle unit at the initial starting stage still reaches the standard, and the beneficial effect of zero emission of the yellow and saltpeter smoke in the whole unit starting process is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of energy-saving and emission-reduction power generation equipment, and in particular to an optimized operation method for flue gas denitrification in a gas-steam combined cycle. Background Art

[0002] With the development of economy and the improvement of people's living standards, the state and the public are paying more and more attention to environmental protection, and the emission standards for flue gas from boilers in generator sets are becoming increasingly higher. Therefore, gas turbine power generation technology has made great progress, and gas-steam combined cycle units have gradually become an important development direction of the power industry with their advantages of high efficiency, low emissions, and flexible operating characteristics. More and more combined cycle units have been put into the market.

[0003] The GE-PG9351FA gas turbine generator set of the gas turbine power plant currently uses the DLN2.0+ burner. During the startup of the unit, even if the denitrification equipment is put into use in time, if the startup method of the typical peak-shaving hot start-stop process is followed, after the generator is connected to the grid, before the denitrification catalyst activity temperature is reached, there will still be an excessive hourly average of nitrogen oxides, and the NO2 emission concentration in the flue gas emissions is relatively high, causing the unit to emit a large amount of brown-yellow smoke. Therefore, how to make the unit's nitrogen oxide emissions meet regulations and control the total amount of nitrogen oxides and NO2 concentration at the initial startup is a technical problem that needs to be solved. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention is proposed.

[0005] To solve the above technical problems, the present invention provides the following technical solutions, a method for optimizing the operation of flue gas denitrification of a gas-steam combined cycle, comprising: obtaining typical peak-shaving conditions of the unit, and determining the start-up time of the unit according to the typical peak-shaving conditions of the unit; determining the ignition time according to the start-up time of the unit, and determining the grid-connected time of the generator according to the ignition time; obtaining the ambient temperature, and determining the average warm-up load according to the ambient temperature; obtaining the exhaust temperature, and correcting the average warm-up load according to the exhaust temperature, and adjusting the current warm-up load of the gas turbine to the average warm-up load; establishing a curve graph of emission concentration values ​​changing with time, and adjusting the current warm-up load according to the emission concentration value curve; obtaining the inlet temperature of the denitrification system, calculating the rate of change of the inlet temperature of the denitrification system, and determining the catalyst input time according to the rate of change of the inlet temperature of the denitrification system.

[0006] As a preferred solution of the method for optimizing flue gas denitrification in a gas-steam combined cycle according to the present invention, the method for determining the start-up time of the unit according to the typical peak load-shaving condition of the unit includes:

[0007] Obtain the minute emission of emissions corresponding to the ignition time of the unit under typical peak load conditions;

[0008] According to the minute emission of the emission, simulate the average value of the current hour and the average value of the next hour of the emission of typical peak load conditions under different ignition times;

[0009] Determine the standard ignition time corresponding to when the emissions do not exceed the standard according to the hourly average value and the next hourly average value of the emissions;

[0010] The unit start time is determined according to the standard ignition time.

[0011] As a preferred scheme of the method for optimizing flue gas denitrification operation of a gas-steam combined cycle described in the present invention, the ignition time is determined according to the unit start-up time, including: if there are multiple standard ignition times corresponding to the time when the current hourly average and the next hourly average of the emissions do not exceed the standard, then the median of the multiple ignition times is calculated, and the median is determined as the standard ignition time.

[0012] As a preferred solution of the method for optimizing flue gas denitrification in a gas-steam combined cycle according to the present invention, the method for determining the average warm-up load according to the ambient temperature comprises:

[0013] A preset ambient temperature matrix T and a preset average warm-up load matrix A are set. For the preset average warm-up load matrix A, A(A1, A2, A3, A4) is set, where A1 is a first preset average warm-up load, A2 is a second preset average warm-up load, A3 is a third preset average warm-up load, A4 is a fourth preset average warm-up load, and A1<A2<A3<A4;

[0014] For the preset ambient temperature matrix T, set T(T1, T2, T3, T4), wherein T1 is the first preset ambient temperature, T2 is the second preset ambient temperature, T3 is the third preset ambient temperature, T4 is the fourth preset ambient temperature, and T1<T2<T3<T4;

[0015] Selecting a corresponding average warm-up load according to the relationship between the current ambient temperature H and the preset ambient temperature matrix T;

[0016] When H<T1, the fourth preset average warm-up load A4 is selected as the average warm-up load;

[0017] When T1≤H<T2, the third preset average warm-up load A3 is selected as the average warm-up load;

[0018] When T2≤H<T3, the second preset average warm-up load A2 is selected as the average warm-up load;

[0019] When T3≤H<T4, the first preset average warm-up load A1 is selected as the average warm-up load.

[0020] As a preferred solution of the method for optimizing flue gas denitrification in a gas-steam combined cycle according to the present invention, the method of correcting the average warm-up load according to the exhaust gas temperature includes:

[0021] A preset exhaust temperature matrix Y and a preset average warm-up load correction coefficient matrix B are set. For the preset average warm-up load correction coefficient matrix B, B(B1, B2, B3, B4) is set, where B1 is a first preset average warm-up load correction coefficient, B2 is a second preset average warm-up load correction coefficient, B3 is a third preset average warm-up load correction coefficient, and B4 is a fourth preset average warm-up load correction coefficient, and 0.5<B1<B2<B3<B4<1.5;

[0022] For the preset exhaust temperature matrix Y, set Y(Y1, Y2, Y3, Y4), where Y1 is the first preset exhaust temperature, Y2 is the second preset exhaust temperature, Y3 is the third preset exhaust temperature, Y4 is the fourth preset exhaust temperature, and Y1<Y2<Y3<Y4;

[0023] According to the relationship between the current exhaust temperature L and the exhaust temperature matrix Y, a corresponding correction coefficient is selected to correct the i-th preset average warm-up load, i=1, 2, 3, 4;

[0024] When L<Y1, the fourth preset average warm-up load correction coefficient B4 is selected to correct the i-th preset average warm-up load, and the corrected average warm-up load is Ai*B4;

[0025] When Y1≤L<Y2, the third preset average warm-up load correction coefficient B3 is selected to correct the i-th preset average warm-up load, and the corrected average warm-up load is Ai*B3;

[0026] When Y2≤L<Y3, the second preset average warm-up load correction coefficient B2 is selected to correct the i-th preset average warm-up load, and the corrected average warm-up load is Ai*B2;

[0027] When Y3≤L<Y4, the first preset average warm-up load correction coefficient B1 is selected to correct the i-th preset average warm-up load, and the corrected average warm-up load is Ai*B1.

[0028] As a preferred solution of the method for optimizing flue gas denitrification in a gas-steam combined cycle according to the present invention, the method of adjusting the current warm-up load according to the emission concentration value curve includes:

[0029] Mapping the emission concentration value curve to the emission concentration value curve under typical peak load conditions;

[0030] If the current emission concentration value exceeds the first preset threshold of the emission concentration value curve under the typical peak load condition, the current warm-up load is adjusted according to the exceeding value.

[0031] As a preferred embodiment of the method for optimizing the operation of flue gas denitration in a gas-steam combined cycle according to the present invention, the step of determining the catalyst input time according to the rate of change of the inlet temperature of the denitration system comprises:

[0032] Get the inlet temperature of the denitrification system within the current period;

[0033] Establish a change curve based on the relationship between the inlet temperature of the denitrification system and time;

[0034] Calculating the inlet temperature change rate according to the change curve;

[0035] Predicting the time required for the inlet temperature to reach a preset temperature based on the inlet temperature change rate;

[0036] Obtain the frequency of the solution pump and valve opening of the denitration system, and calculate the time it takes for the catalyst to be fully invested;

[0037] The difference between the time required for the inlet temperature to reach the preset temperature and the time when the catalyst is fully introduced is calculated, and the difference is determined as the catalyst introduction time.

[0038] As a preferred solution of the method for optimizing flue gas denitration in a gas-steam combined cycle of the present invention, data simulation and deduction are performed according to the control of various indicators during the startup of the unit;

[0039] According to the data simulation results, the optimal values ​​of various indicators in the computer group startup process are calculated;

[0040] Establish the unit startup theoretical model according to the optimal values ​​of each index;

[0041] Compare the difference between each index in the actual startup process of the unit and the theoretical model of the unit startup;

[0042] If the difference value is less than the second preset threshold, the operating condition of the unit during actual startup is updated to the typical peak load-shaving operating condition of the unit;

[0043] When the unit is shut down, close the chimney damper of the waste heat boiler to insulate the waste heat boiler.

[0044] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and wherein when the processor executes the computer program, the steps of any one of the methods for optimizing the operation of flue gas denitrification in a gas-steam combined cycle are implemented.

[0045] A computer-readable storage medium having a computer program stored thereon, characterized in that when the computer program is executed by a processor, the steps of any one of the methods for optimizing the operation of flue gas denitrification in a gas-steam combined cycle are implemented.

[0046] Beneficial effects of the present invention: The present invention provides a more reasonable unit startup optimization strategy by adjusting the unit startup time, the unit warm-up load value, and the denitrification system input parameters, thereby reducing nitrogen oxide emissions and NO2 concentration in the flue gas, so that the nitrogen oxide emissions of the combined cycle unit in the initial startup stage still meet the standards, achieving the beneficial effect of zero nitrate smoke emissions throughout the entire unit startup process. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0048] Figure 1 A schematic flow chart of a method for optimizing flue gas denitrification in a gas-steam combined cycle is provided as an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0050] Example 1, reference Figure 1 , which is the first embodiment of the present invention, provides a method for optimizing flue gas denitrification in a gas-steam combined cycle, comprising:

[0051] S101, obtaining a typical peak-shaving operating condition of the unit, and determining a start-up time of the unit according to the typical peak-shaving operating condition of the unit;

[0052] In some embodiments of the present application, determining the start-up time of the unit according to the typical peak load-shaving condition of the unit includes:

[0053] Obtain the minute emission of emissions corresponding to the ignition time of the unit under typical peak load conditions;

[0054] According to the minute emission of the emission, simulate the average value of the current hour and the average value of the next hour of the emission of typical peak load conditions under different ignition times;

[0055] Determine the standard ignition time corresponding to when the emissions do not exceed the standard according to the hourly average value and the next hourly average value of the emissions;

[0056] The unit start time is determined according to the standard ignition time.

[0057] In some embodiments of the present application, if there are multiple standard ignition times corresponding to when the current hourly average and the next hourly average of the emissions do not exceed the standard, the median of the multiple ignition times is calculated and the median is determined as the standard ignition time.

[0058] The combined cycle unit used in this embodiment is equipped with an SCR denitrification system. Since there is a vacuum period of 30-40 minutes between the start-up and ignition of the unit and the SCR catalyst reaching the active temperature, the nitrogen oxide emissions exceed the standard and yellow smoke is discharged during the vacuum period. Therefore, this embodiment optimizes the start-up time of the unit to make the hourly average nitrogen oxide emissions during the vacuum period meet the standard, detect the actual minute nitrogen oxide emissions under typical peak-shaving conditions, substitute the actual value into the conversion formula NOx(15%O2)=NOx*(20.9%-15%) / (20.9%-O2%) to calculate the conversion value, and simulate the typical peak-shaving conditions of the unit at different start-up times by moving the conversion value forward and backward. The hourly average of nitrogen oxides is detected, and the ignition time at which the current hourly average and the next hourly average of nitrogen oxide emission concentration do not exceed the standard is detected (according to the Jiangsu Province Stationary Gas Turbine Air Pollutant Emission Standard, the nitrogen oxide emissions of in-service units in 2023 are required to be no more than 30 mg / m3). In this embodiment, the unit startup process is program-controlled, and the time difference from the startup time to the ignition time is about 15 minutes. Therefore, the startup time can be determined according to the ignition time to ensure that the current hourly average and the next hourly average of nitrogen oxide emission concentration do not exceed the standard. The startup time determination method of this embodiment often has multiple startup times. In order to ensure that the emissions meet the standards, this embodiment selects the median of multiple ignition times and determines the median as the standard ignition time.

[0059] 1. (Original zero emission method of yellow smoke) Obtain the typical peak-shaving conditions of the unit, determine the unit start-up time according to the typical peak-shaving conditions of the unit; determine the ignition time according to the unit start-up time, and determine the generator grid-connected time according to the ignition time; obtain the ambient temperature, determine the average warm-up load according to the ambient temperature; obtain the exhaust temperature, correct the average warm-up load according to the exhaust temperature, and adjust the current warm-up load of the gas turbine to the average warm-up load; establish a curve of the emission concentration value changing with time, and adjust the current warm-up load according to the emission concentration value curve; obtain the inlet temperature of the denitrification system, calculate the rate of change of the inlet temperature of the denitrification system, and determine the catalyst input time according to the rate of change of the inlet temperature of the denitrification system. The hourly average value of nitrogen oxide emissions is optimized, and zero yellow smoke emissions are achieved during the entire unit startup process.

[0060] 2. On the basis of 1, according to the nitrogen oxide emission level, the number of denitrification spray guns put into use, the operating frequency of the denitrification solution pump, the outlet pressure, the opening of each denitrification solution valve, while ensuring that the emission standard of 30mg / m3 is not exceeded, the use of urea for denitrification can be reduced as much as possible to reduce the company's environmental protection costs.

[0061] Embodiment 2 is the second embodiment of the present invention, which provides a method for optimizing the operation of flue gas denitrification in a gas-steam combined cycle;

[0062] S102, determining the ignition time according to the unit start-up time, and determining the generator grid connection time according to the ignition time;

[0063] In this embodiment, the unit startup process is program-controlled, and the time difference from the startup time to the ignition time and the time difference from the ignition time to the generator grid-connected time are both about 15 minutes, so the startup time and the grid-connected time can be determined according to the ignition time.

[0064] S103, obtaining the ambient temperature, and determining the average warm-up load according to the ambient temperature;

[0065] In some embodiments of the present application, determining the average warm-up load according to the ambient temperature includes:

[0066] A preset ambient temperature matrix T and a preset average warm-up load matrix A are set. For the preset average warm-up load matrix A, A(A1, A2, A3, A4) is set, where A1 is a first preset average warm-up load, A2 is a second preset average warm-up load, A3 is a third preset average warm-up load, A4 is a fourth preset average warm-up load, and A1<A2<A3<A4;

[0067] For the preset ambient temperature matrix T, set T(T1, T2, T3, T4), wherein T1 is the first preset ambient temperature, T2 is the second preset ambient temperature, T3 is the third preset ambient temperature, T4 is the fourth preset ambient temperature, and T1<T2<T3<T4;

[0068] Selecting a corresponding average warm-up load according to the relationship between the current ambient temperature H and the preset ambient temperature matrix T;

[0069] When H<T1, the fourth preset average warm-up load A4 is selected as the average warm-up load;

[0070] When T1≤H<T2, the third preset average warm-up load A3 is selected as the average warm-up load;

[0071] When T2≤H<T3, the second preset average warm-up load A2 is selected as the average warm-up load;

[0072] When T3≤H<T4, the first preset average warm-up load A1 is selected as the average warm-up load.

[0073] In this embodiment, after the generator is connected to the grid, the average warm-up load can be determined by detecting the ambient temperature. When the ambient temperature is higher, the warm-up load should be reduced to prevent the emission of yellow smoke due to excessive NO2 emission concentration.

[0074] S104, obtaining the exhaust gas temperature, correcting the average warm-up load according to the exhaust gas temperature, and adjusting the current warm-up load of the gas turbine toward the average warm-up load;

[0075] In some embodiments of the present application, the correcting the average warm-up load according to the exhaust gas temperature includes:

[0076] A preset exhaust temperature matrix Y and a preset average warm-up load correction coefficient matrix B are set. For the preset average warm-up load correction coefficient matrix B, B(B1, B2, B3, B4) is set, where B1 is a first preset average warm-up load correction coefficient, B2 is a second preset average warm-up load correction coefficient, B3 is a third preset average warm-up load correction coefficient, and B4 is a fourth preset average warm-up load correction coefficient, and 0.5<B1<B2<B3<B4<1.5;

[0077] For the preset exhaust temperature matrix Y, set Y(Y1, Y2, Y3, Y4), where Y1 is the first preset exhaust temperature, Y2 is the second preset exhaust temperature, Y3 is the third preset exhaust temperature, Y4 is the fourth preset exhaust temperature, and Y1<Y2<Y3<Y4;

[0078] According to the relationship between the current exhaust temperature L and the exhaust temperature matrix Y, a corresponding correction coefficient is selected to correct the i-th preset average warm-up load, i=1, 2, 3, 4;

[0079] When L<Y1, the fourth preset average warm-up load correction coefficient B4 is selected to correct the i-th preset average warm-up load, and the corrected average warm-up load is Ai*B4;

[0080] When Y1≤L<Y2, the third preset average warm-up load correction coefficient B3 is selected to correct the i-th preset average warm-up load, and the corrected average warm-up load is Ai*B3;

[0081] When Y2≤L<Y3, the second preset average warm-up load correction coefficient B2 is selected to correct the i-th preset average warm-up load, and the corrected average warm-up load is Ai*B2;

[0082] When Y3≤L<Y4, the first preset average warm-up load correction coefficient B1 is selected to correct the i-th preset average warm-up load, and the corrected average warm-up load is Ai*B1.

[0083] In this embodiment, the average warm-up load is corrected by detecting the exhaust temperature of the unit. When the operation starts, the exhaust temperature is low. The average warm-up load is corrected by the correction coefficient to speed up the exhaust temperature increase rate. Once the exhaust temperature is higher than 500°C, the average warm-up load is corrected by the correction coefficient, and the warm-up load is adjusted to the average warm-up load to reduce the exhaust temperature. A slight change of 500°C exhaust temperature of the gas turbine has little effect on raising the temperature before the denitrification catalyst to the active temperature. Therefore, by controlling the exhaust temperature below 500°C, the overall nitrogen oxide emission level before the denitrification system is put into use can be effectively reduced, thereby alleviating the emission control pressure two hours before and after grid connection.

[0084] S105, establishing a curve chart showing the emission concentration value changing over time, and adjusting the current warm-up load according to the emission concentration value curve;

[0085] In some embodiments of the present application, adjusting the current warm-up load according to the emission concentration value curve includes:

[0086] Mapping the emission concentration value curve to the emission concentration value curve under typical peak load conditions;

[0087] If the current emission concentration value exceeds the first preset threshold of the emission concentration value curve under the typical peak load condition, the current warm-up load is adjusted according to the exceeding value.

[0088] In this embodiment, the nitrogen oxide emission concentration conversion value curve under typical peak-shaving conditions is obtained, and the nitrogen oxide conversion value under the current operating conditions is monitored and calculated in real time to draw the nitrogen oxide emission concentration curve. If it is found that the current emission volume deviates abnormally from the curve and exceeds the first preset threshold, the current warm-up load is adjusted in time to ensure that the emissions meet the standards.

[0089] S106, obtaining the inlet temperature of the denitration system, calculating the rate of change of the inlet temperature of the denitration system, and determining the catalyst input time according to the rate of change of the inlet temperature of the denitration system.

[0090] In some embodiments of the present application, the step of determining the catalyst input time according to the rate of change of the inlet temperature of the denitration system includes:

[0091] Get the inlet temperature of the denitrification system within the current period;

[0092] Establish a change curve based on the relationship between the inlet temperature of the denitrification system and time;

[0093] Calculating the inlet temperature change rate according to the change curve;

[0094] Predicting the time required for the inlet temperature to reach a preset temperature based on the inlet temperature change rate;

[0095] Obtain the frequency of the solution pump and valve opening of the denitration system, and calculate the time it takes for the catalyst to be fully invested;

[0096] The difference between the time required for the inlet temperature to reach the preset temperature and the time when the catalyst is fully introduced is calculated, and the difference is determined as the catalyst introduction time.

[0097] In this embodiment, the inlet temperature of the denitrification system is monitored in real time and a curve of the inlet temperature changing with time is established. The rate of change of the inlet temperature can be calculated by the speed of change of the curve and the growth trend of the inlet temperature can be predicted. After obtaining enough data, the time when the inlet temperature reaches the preset temperature can be predicted. The preset temperature is the optimal activity temperature of the catalyst. The time when the catalyst is fully invested is calculated by obtaining the frequency of the solution pump and the valve opening of the denitrification system. The time when the catalyst is fully invested is subtracted from the time when the inlet temperature reaches the preset temperature to obtain the catalyst investment time. The catalyst investment time can be appropriately advanced to improve the working efficiency of the denitrification system and alleviate the emission control pressure two hours before and after grid connection.

[0098] In some embodiments of the present application, further comprising:

[0099] Carry out data simulation and deduction according to the control of various indicators during the unit startup process;

[0100] According to the data simulation results, the optimal values ​​of various indicators in the computer group startup process are calculated;

[0101] Establish the unit startup theoretical model according to the optimal values ​​of each index;

[0102] Compare the difference between each index in the actual startup process of the unit and the theoretical model of the unit startup;

[0103] If the difference value is less than the second preset threshold, the operating condition during the actual startup of the unit is updated to the typical peak-shaving operating condition of the unit.

[0104] In this embodiment, after the unit ends its operation, the unit operating condition indicators adjusted by the method of the embodiment of the present application are obtained, including the start-up time, the average warm-up load, the catalyst input time of the denitrification system and the corresponding nitrogen oxide emission concentration. The above indicators are subjected to data deduction, and the optimal values ​​of each indicator in the startup process are obtained through optimization. A theoretical model for unit startup is established based on the optimal values ​​of the indicators, and the difference between the theoretical model and the actual indicators is calculated. In this embodiment, the difference value of each indicator is calculated through the chi-square test. The smaller the difference value, the closer the actual indicator is to the theoretical indicator. If the difference value is less than the second preset threshold, the typical peak-shaving operating condition can be updated according to the current indicator.

[0105] In some embodiments of the present application, it also includes: when the unit is shut down, closing the chimney damper of the waste heat boiler to insulate the waste heat boiler.

[0106] In this embodiment, the daily peak load regulation of the unit can significantly improve the catalyst activity by strengthening the insulation of the boiler, thereby significantly reducing the NO2 emission concentration during the startup process.

[0107] In order to further explain the technical idea of ​​the present invention, the technical solution of the present invention is now described in combination with specific application scenarios.

[0108] By applying the above technical solutions, the unit startup time is optimized through the nitrogen oxide emission concentration under the typical peak-shaving conditions of the unit, so that the hourly average nitrogen oxide emission of the unit meets the standard, and the unit warm-up load is reset by detecting the ambient temperature and exhaust temperature, and the warm-up load is adjusted by real-time monitoring of emission concentration to ensure that emissions do not exceed the standard. After the generator is connected to the grid, the catalyst is added in time through real-time monitoring of the inlet temperature of the denitrification system to improve the working efficiency of the denitrification system and facilitate subsequent regulation. After the unit is shut down, insulation measures are taken for the waste heat boiler in time to improve the catalyst activity, so that the nitrogen oxide emissions of the combined cycle unit in the initial startup are still up to standard, achieving zero nitrate and yellow smoke emissions throughout the unit startup process.

[0109] Embodiment 3, the third embodiment of the present invention, is different from the first two embodiments in that:

[0110] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0111] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0112] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0113] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

Claims

1. A method for optimizing flue gas denitrification in a gas-steam combined cycle, characterized in that: include, Obtain the typical peak-shaving operating conditions of the unit and determine the unit start-up time based on the typical peak-shaving operating conditions of the unit; Determine the ignition time according to the unit start-up time, and determine the generator grid connection time according to the ignition time; Obtain the ambient temperature and determine the average warm-up load according to the ambient temperature; Obtaining the exhaust gas temperature, correcting the average warm-up load according to the exhaust gas temperature, and adjusting the current warm-up load of the gas turbine toward the average warm-up load; Establish a curve chart showing the emission concentration value changing over time, and adjust the current warm-up load according to the emission concentration value curve; Obtain the inlet temperature of the denitrification system, calculate the rate of change of the inlet temperature of the denitrification system, and determine the catalyst input time according to the rate of change of the inlet temperature of the denitrification system.

2. A gas-steam combined cycle flue gas denitrification optimization operation method as claimed in claim 1, characterized in that: Determining the unit startup time according to the typical peak load-shaving operating conditions of the unit includes: Obtain the minute emission of emissions corresponding to the ignition time of the unit under typical peak load conditions; According to the minute emission of the emission, simulate the average value of the current hour and the average value of the next hour of the emission of typical peak load conditions under different ignition times; Determine the standard ignition time corresponding to when the emissions do not exceed the standard according to the average value of the current hour and the average value of the next hour of the emissions; The unit start time is determined according to the standard ignition time.

3. A method for optimizing flue gas denitrification in a gas-steam combined cycle as claimed in claim 2, characterized in that: Determining the ignition time according to the unit startup time includes, if there are multiple standard ignition times corresponding to the current hourly average and the next hourly average of the emissions that do not exceed the standard, calculating the median of the multiple ignition times, and determining the median as the standard ignition time.

4. The method for optimizing flue gas denitrification in a gas-steam combined cycle according to claim 1, characterized in that: Determining the average warm-up load according to the ambient temperature includes: A preset ambient temperature matrix T and a preset average warm-up load matrix A are set. For the preset average warm-up load matrix A, A(A1, A2, A3, A4) is set, where A1 is a first preset average warm-up load, A2 is a second preset average warm-up load, A3 is a third preset average warm-up load, A4 is a fourth preset average warm-up load, and A1<A2<A3<A4; For the preset ambient temperature matrix T, set T(T1, T2, T3, T4), wherein T1 is the first preset ambient temperature, T2 is the second preset ambient temperature, T3 is the third preset ambient temperature, T4 is the fourth preset ambient temperature, and T1<T2<T3<T4; Selecting a corresponding average warm-up load according to the relationship between the current ambient temperature H and the preset ambient temperature matrix T; When H<T1, the fourth preset average warm-up load A4 is selected as the average warm-up load; When T1≤H<T2, the third preset average warm-up load A3 is selected as the average warm-up load; When T2≤H<T3, the second preset average warm-up load A2 is selected as the average warm-up load; When T3≤H<T4, the first preset average warm-up load A1 is selected as the average warm-up load.

5. A gas-steam combined cycle flue gas denitrification optimization operation method as claimed in claim 4, characterized in that: The correction of the average warm-up load according to the exhaust gas temperature includes: A preset exhaust temperature matrix Y and a preset average warm-up load correction coefficient matrix B are set. For the preset average warm-up load correction coefficient matrix B, B(B1, B2, B3, B4) is set, where B1 is a first preset average warm-up load correction coefficient, B2 is a second preset average warm-up load correction coefficient, B3 is a third preset average warm-up load correction coefficient, and B4 is a fourth preset average warm-up load correction coefficient, and 0.5<B1<B2<B3<B4<1.5; For the preset exhaust temperature matrix Y, set Y(Y1, Y2, Y3, Y4), where Y1 is the first preset exhaust temperature, Y2 is the second preset exhaust temperature, Y3 is the third preset exhaust temperature, Y4 is the fourth preset exhaust temperature, and Y1<Y2<Y3<Y4; According to the relationship between the current exhaust temperature L and the exhaust temperature matrix Y, a corresponding correction coefficient is selected to correct the i-th preset average warm-up load, i=1, 2, 3, 4; When L<Y1, the fourth preset average warm-up load correction coefficient B4 is selected to correct the i-th preset average warm-up load, and the corrected average warm-up load is Ai*B4; When Y1≤L<Y2, the third preset average warm-up load correction coefficient B3 is selected to correct the i-th preset average warm-up load, and the corrected average warm-up load is Ai*B3; When Y2≤L<Y3, the second preset average warm-up load correction coefficient B2 is selected to correct the i-th preset average warm-up load, and the corrected average warm-up load is Ai*B2; When Y3≤L<Y4, the first preset average warm-up load correction coefficient B1 is selected to correct the i-th preset average warm-up load, and the corrected average warm-up load is Ai*B1.

6. The method for optimizing flue gas denitrification in a gas-steam combined cycle according to claim 1, characterized in that: The adjusting the current warm-up load according to the emission concentration value curve includes: Mapping the emission concentration value curve to the emission concentration value curve under typical peak load conditions; If the current emission concentration value exceeds the first preset threshold of the emission concentration value curve under the typical peak load condition, the current warm-up load is adjusted according to the exceeding value.

7. The method for optimizing flue gas denitrification in a gas-steam combined cycle according to claim 1, characterized in that: The step of determining the catalyst input time according to the change rate of the inlet temperature of the denitration system comprises: Get the inlet temperature of the denitrification system within the current period; Establish a change curve based on the relationship between the inlet temperature of the denitrification system and time; Calculating the inlet temperature change rate according to the change curve; Predicting the time required for the inlet temperature to reach a preset temperature based on the inlet temperature change rate; Obtain the frequency of the solution pump and valve opening of the denitration system, and calculate the time it takes for the catalyst to be fully invested; The difference between the time required for the inlet temperature to reach the preset temperature and the time when the catalyst is fully introduced is calculated, and the difference is determined as the catalyst introduction time.

8. The method for optimizing flue gas denitrification in a gas-steam combined cycle according to claim 1, characterized in that: include, Carry out data simulation and deduction according to the control of various indicators during the unit startup process; According to the data simulation results, the optimal values ​​of various indicators in the computer group startup process are calculated; Establish the unit startup theoretical model according to the optimal values ​​of each index; Compare the difference between each index in the actual startup process of the unit and the theoretical model of the unit startup; If the difference value is less than the second preset threshold, the operating condition of the unit during actual startup is updated to the typical peak load condition of the unit; When the unit is shut down, close the chimney damper of the waste heat boiler to insulate the waste heat boiler.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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