Operation control method and device for coal-fired unit

Abstract

The embodiment of the invention relates to the technical field of coal-fired unit control, and provides an operation control method and device for a coal-fired unit. According to the embodiment of the invention, by obtaining the sulfur content of the fire coal input into the coal-fired unit and the NO concentration of the inlet of the SCR reactor connected with the coal-fired unit, the lowest continuous ammonia spraying operation temperature and the longest inactivation operation time of the coal-fired unit under the typical low-load condition under the deep peak regulation condition can be obtained in real time; and in combination with the typical low-load operation temperature of the coal-fired unit under the deep peak regulation condition, the temperature increasing bypass input time can be reasonably arranged, so that the boiler efficiency reduction degree is effectively reduced, and the operation economy of the coal-fired unit is improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of coal-fired unit control, and in particular to an operation control method and device for a coal-fired unit. Background Art

[0002] After implementing ultra-low / ultra-low emission and flexible peak-shaving operation modes, coal-fired units have encountered a series of problems such as serious blockage of air preheaters, large fluctuations in nitrogen oxide (NOx) emission concentrations, and low-load operation of flue gas denitrification, which have greatly reduced the energy-saving and emission-reduction operation level of coal-fired units. Especially under low-load conditions, the flexible peak-shaving of coal-fired units causes the inlet flue gas temperature of the Selective Catalytic Reduction (SCR) reactor to be low, making the problems caused by the original high denitrification efficiency operation of SCR more common and serious.

[0003] In order to meet the requirements of flexible peak regulation and full-load denitrification of coal-fired units, the existing technology provides three solutions. The first is the catalyst temperature increase modification scheme commonly used in coal-fired power plants, that is, the use of water bypass, economizer flue gas bypass and other schemes to increase the flue gas temperature at the inlet of the SCR reactor. These modification schemes have obvious temperature increase effects, but the investment is high and the economy is poor. At the same time, the boiler efficiency will be reduced during operation. The second is a scheme to adjust the operation mode of the coal-fired unit. Although the inlet flue gas temperature of the SCR reactor under low load conditions of the power plant adopting this scheme is low, the gap from the minimum ammonia injection operating temperature is small. Therefore, this type of power plant can adjust the operation mode of the coal-fired unit by investing in high-temperature heaters in advance, adjusting the swing angle of the boiler burner, the tail steam temperature regulating damper door, mixing low-sulfur coal and delaying the soot blowing of the heating surface, so as to increase the inlet flue gas temperature of the SCR flue gas denitrification reactor to above the minimum ammonia injection operating temperature. However, although this scheme is more economical, the temperature increase effect is limited. The third is to utilize the reversible deactivation characteristics of the catalyst ammonium bisulfate, combined with the characteristics of low flue gas temperature at low load and high flue gas temperature at high load of coal-fired units, to allow the first layer of SCR flue gas denitrification catalyst to be moderately deactivated at low load and heated and restored at high load. This solution does not involve the modification of the coal-fired unit, but only needs to comply with the normal operating mode of the coal-fired unit, but has additional requirements for the operating conditions of the coal-fired unit.

[0004] In the actual operation of coal-fired units, changes in coal quality will cause a large change in the sulfur content of the coal used by the coal-fired units, which determines that the minimum ammonia injection operating temperature is constantly changing. At the same time, since the catalyst temperature increase will cause the boiler efficiency of the coal-fired unit to decrease, if the coal-fired unit is controlled only by the initial design conditions during operation, it will not be able to adapt to the change in coal quality. Many bypasses are not required or the bypass time is too long, which will affect the economy of the coal-fired unit. At this time, the control strategy of the coal-fired unit needs to be constantly adjusted to achieve the most economical operation mode. Summary of the invention

[0005] The present disclosure aims to solve at least one of the problems existing in the prior art and provides an operation control method and device for a coal-fired unit.

[0006] In one aspect of the present disclosure, there is provided an operation control method for a coal-fired unit, the operation control method comprising:

[0007] Obtaining the sulfur content of the coal input into the coal-fired unit and the NO concentration at the inlet of the SCR reactor connected to the coal-fired unit;

[0008] Determine, according to the sulfur content and the inlet NO concentration, the minimum continuous ammonia injection operating temperature of the SCR reactor and the maximum deactivation time of the catalyst in the SCR reactor when the coal-fired unit operates at a typical low-load operating temperature under deep peak-shaving conditions;

[0009] The minimum continuous ammonia injection operating temperature is compared with the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions. Based on the comparison result and the maximum deactivation time, the maximum duration of the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions is controlled and it is decided whether to open the temperature increase bypass.

[0010] Optionally, determining, according to the sulfur content and the inlet NO concentration, the minimum continuous ammonia injection operating temperature of the SCR reactor and the maximum deactivation time of the catalyst in the SCR reactor when the coal-fired unit operates at a typical low-load operating temperature under deep peak-shaving conditions, comprises:

[0011] According to the sulfur content, the SO in the coal-fired flue gas generated by the coal-fired unit is determined. 3 content;

[0012] Determining the amount of ammonia injected into the SCR reactor according to the inlet NO concentration;

[0013] According to the SO 3 The minimum continuous ammonia injection operating temperature and the maximum deactivation time are determined by the content and the ammonia injection amount of the SCR reactor.

[0014] Optionally, the determining the minimum continuous ammonia injection operating temperature and the maximum deactivation time respectively according to the sulfur trioxide content in the coal-fired flue gas and the ammonia injection amount of the SCR reactor includes:

[0015] According to Formula 1, the minimum continuous ammonia injection operating temperature is determined:

[0016] T mot =α×(C NH3,in ×CSO3,in ) β Formula 1;

[0017] Among them, T mot Indicates the minimum continuous ammonia injection operating temperature, C NH3,in represents the amount of ammonia injected into the SCR reactor, C SO3,in Indicates the SO in the coal-fired flue gas 3 content, α represents the first temperature coefficient, and β represents the second temperature coefficient.

[0018] Optionally, the determining the minimum continuous ammonia injection operation temperature and the maximum deactivation time respectively according to the sulfur trioxide content in the coal-fired flue gas and the ammonia injection amount of the SCR reactor further includes:

[0019] According to Formula 2, the maximum inactivation time is determined:

[0020]

[0021] Wherein, t represents the longest inactivation time, α t represents the first time coefficient, β t Represents the second time coefficient.

[0022] Optionally, the operation control method further includes:

[0023] Determine the first temperature coefficient and the second temperature coefficient by using a laboratory temperature test;

[0024] The laboratory temperature test includes:

[0025] Taking the first layer of catalyst in the SCR reactor as a catalyst sample;

[0026] The test was conducted in the laboratory, and the test flue gas was introduced into the catalyst sample. The flue gas condition of the test flue gas was NO+NH 3 +O 2 +SO 2 +SO 3 +CO 2 +H 2 O, among which NO and NH 3 The concentration ratio is set to 1.0;

[0027] The NH 3 Concentration and SO 3 The concentrations were set to different values ​​to obtain multiple sets of smoke data;

[0028] Based on each group of flue gas data, a cooling test and a deactivation temperature test are performed respectively to obtain the minimum continuous ammonia injection operation temperature T corresponding to each group of flue gas data. mot ;

[0029] The NH corresponding to each group of flue gas data 3 Concentration and SO 3 Concentration and its corresponding minimum continuous ammonia injection operating temperature T mot Substitute T mot =α×(C NH3,in ×C SO3,in ) β Perform data fitting to obtain specific values ​​of α and β.

[0030] Optionally, the cooling test includes: keeping the test temperature T1 unchanged, testing for a preset time, and measuring the NO content and NH 3 content, according to the NO content and the NH 3 content, calculate the activity k of the catalyst sample at the test temperature T1 at the i-th moment i With initial activity k 0 The ratio k i / k 0 , if k i / k 0 If the temperature remains unchanged within the preset time, the test temperature T1 is gradually reduced, and the temperature reduction test is repeated until k is obtained. i / k 0 The test temperature during the drop is T2;

[0031] The deactivation temperature test includes: testing the preset time at the test temperature T2, increasing the test temperature T2 to the designed normal operating temperature corresponding to the catalyst sample, testing the preset time again, and calculating the activity k of the catalyst sample at the i-th moment at the designed normal operating temperature. i With initial activity k 0 The ratio k i / k 0 , if k i / k 0 If k gradually recovers to 1 within the preset time, the test temperature T2 is gradually reduced, and the deactivation temperature test is repeated until k is obtained. i / k 0 The test temperature Tn when it cannot be restored, the previous test temperature Tn-1 of the test temperature Tn is used as the lowest continuous ammonia injection operation temperature T of the catalyst sample under the current flue gas data of the flue gas condition. mot .

[0032] Optionally, the operation control method further includes:

[0033] Determine the first time factor and the second time factor by using a maximum allowable deactivation time test at a typical low-load temperature;

[0034] The test of the longest allowable deactivation time at the typical low load temperature includes:

[0035] Taking the first layer of catalyst in the SCR reactor as a catalyst sample;

[0036] The test was conducted in the laboratory, and the test flue gas was introduced into the catalyst sample. The flue gas condition of the test flue gas was NO+NH 3 +O 2 +SO 2 +SO 3 +CO 2 +H 2 O, among which NO and NH 3 The concentration ratio is set to 1.0;

[0037] The NH 3 Concentration and SO 3 The concentrations were set to different values ​​to obtain multiple sets of smoke data;

[0038] Based on each group of flue gas data, a deactivation time test is performed to obtain the longest deactivation time t of the catalyst sample under the typical low-load operating temperature under deep peak regulation conditions under each group of flue gas data;

[0039] The NH corresponding to each group of flue gas data 3 Concentration and SO 3 The concentration and its corresponding longest inactivation time t are substituted into Fit the data and get α t and β t The specific value of .

[0040] Optionally, the inactivation time test includes:

[0041] The test temperature is set to the typical low-load operating temperature T of the coal-fired unit under deep peak regulation conditions. min ;

[0042] Keeping the test temperature constant and the test time specified, the NO and NH 3 The content test, according to the measured NO content and NH 3 content, calculate the activity k of the catalyst sample at the test temperature at the i-th moment i With initial activity k 0 The ratio k i / k 0 , increase the test temperature to the normal operating temperature of the catalyst sample under the typical low load condition under deep peak regulation, and calculate k i / k 0 , if k i / k0 If it can be restored to 1, the specified time is gradually extended and the deactivation time test is repeated until k is obtained. i / k 0 The specified time when the recovery is impossible, the previous specified time of the specified time is used as the typical low-load operating temperature T of the catalyst sample under deep peak regulation conditions. min The longest inactivation time t under .

[0043] Optionally, comparing the minimum continuous ammonia injection operating temperature with the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions, and controlling the maximum duration of the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions according to the comparison result and the maximum deactivation time, and deciding whether to open the temperature-raising bypass, comprises:

[0044] If the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions is greater than or equal to the minimum continuous ammonia injection operating temperature, the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions is maintained, and the temperature-raising bypass is kept closed;

[0045] If the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions is lower than the minimum continuous ammonia injection operating temperature, the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions is maintained, and when the longest duration of the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions reaches the maximum deactivation time, the temperature raising bypass is opened to raise the flue gas temperature at the SCR inlet to the minimum continuous ammonia injection operating temperature.

[0046] Another aspect of the present disclosure provides an operation control device for a coal-fired unit, the operation control device comprising:

[0047] An acquisition module, used to acquire the sulfur content of the coal input into the coal-fired unit and the inlet NO concentration of the SCR reactor connected to the coal-fired unit;

[0048] A determination module, for determining, according to the sulfur content and the inlet NO concentration, a minimum continuous ammonia injection operating temperature of the SCR reactor and a maximum deactivation time of a catalyst in the SCR reactor when the coal-fired unit operates at a typical low-load operating temperature under deep peak-shaving conditions;

[0049] A control module is used to compare the minimum continuous ammonia injection operating temperature with the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions, and control the maximum duration of the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions and decide whether to open the temperature increase bypass based on the comparison result and the maximum deactivation time.

[0050] Optionally, the operation control device further includes a laboratory temperature test module, and the laboratory temperature test module is used to:

[0051] Determine the first temperature coefficient and the second temperature coefficient by using a laboratory temperature test;

[0052] The laboratory temperature test includes:

[0053] Taking the first layer of catalyst in the SCR reactor as a catalyst sample;

[0054] The test was conducted in the laboratory, and the test flue gas was introduced into the catalyst sample. The flue gas condition of the test flue gas was NO+NH 3 +O 2 +SO 2 +SO 3 +CO 2 +H 2 O, among which NO and NH 3 The concentration ratio is set to 1.0;

[0055] The NH 3 Concentration and SO 3 The concentrations were set to different values ​​to obtain multiple sets of smoke data;

[0056] Based on each group of flue gas data, a cooling test and a deactivation temperature test are performed respectively to obtain the minimum continuous ammonia injection operation temperature T corresponding to each group of flue gas data. mot :

[0057] The NH corresponding to each group of flue gas data 3 Concentration and SO 3 Concentration and its corresponding minimum continuous ammonia injection operating temperature T mot Substitute T mot =α×(C NH3,in ×C SO3,in )β is used to fit the data and obtain the specific values ​​of α and β.

[0058] Optionally, the operation control device further comprises a longest allowable deactivation time test module at a typical low load temperature, wherein the longest allowable deactivation time test module at a typical low load temperature is used to:

[0059] Determine the first time factor and the second time factor by using a maximum allowable deactivation time test at a typical low-load temperature;

[0060] The test of the longest allowable deactivation time at the typical low load temperature includes:

[0061] Taking the first layer of catalyst in the SCR reactor as a catalyst sample;

[0062] The test was conducted in the laboratory, and the test flue gas was introduced into the catalyst sample. The flue gas condition of the test flue gas was NO+NH 3 +O 2 +SO 2 +SO 3 +CO 2 +H 2 O, among which NO and NH 3 The concentration ratio is set to 1.0;

[0063] The NH 3 Concentration and SO 3 The concentrations were set to different values ​​to obtain multiple sets of smoke data;

[0064] Based on each group of flue gas data, a deactivation time test is performed to obtain the longest deactivation time t of the catalyst sample under the typical low-load operating temperature under deep peak regulation conditions under each group of flue gas data;

[0065] The NH corresponding to each group of flue gas data 3 Concentration and SO 3 The concentration and its corresponding longest inactivation time t are substituted into Fit the data and get α t and β t The specific value of .

[0066] Compared with the prior art, the present disclosure can obtain the sulfur content of the coal input into the coal-fired unit and the inlet NO concentration of the SCR reactor connected to the coal-fired unit, so as to obtain in real time the minimum continuous ammonia injection operating temperature and the longest deactivation operating time of the coal-fired unit under typical low-load conditions under deep peak-shaving conditions, and can reasonably arrange the time for the temperature increase bypass to be put into use in combination with the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions, thereby effectively reducing the degree of boiler efficiency reduction and improving the economy of the coal-fired unit operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0068] Figure 1 A flow chart of an operation control method of a coal-fired unit provided in one embodiment of the present disclosure;

[0069] Figure 2A schematic structural diagram of an operation control device for a coal-fired unit provided in another embodiment of the present disclosure. DETAILED DESCRIPTION

[0070] In order to make the purpose, technical scheme and advantages of the embodiments of the present disclosure clearer, the embodiments of the present disclosure will be described in detail below in conjunction with the accompanying drawings. However, it can be understood by those skilled in the art that in each embodiment of the present disclosure, many technical details are proposed in order to enable readers to better understand the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed for protection in the present disclosure can also be implemented. The division of the following embodiments is for the convenience of description and should not constitute any limitation on the specific implementation of the present disclosure. The various embodiments can be combined and referenced with each other without contradiction.

[0071] One embodiment of the present disclosure relates to an operation control method for a coal-fired unit, the process of which is as follows: Figure 1 As shown, it includes steps S110 to S130.

[0072] Step S110, obtaining the sulfur content of the coal input to the coal-fired unit and the NO concentration at the inlet of the SCR reactor connected to the coal-fired unit.

[0073] Specifically, step S110 can utilize an element online analysis test device disposed on the coal conveying belt of the coal-fired unit to analyze the sulfur (S) content in the coal quality in real time, thereby obtaining the sulfur content of the coal input into the coal-fired unit. Among them, the element online analysis test device can adopt a laser-induced breakdown spectroscopy (LIBS) online analysis test device. As a new material identification and quantitative analysis technology, LIBS technology is widely used in online detection at industrial sites. Its analysis is fast, and it can analyze multiple elements and detect almost all solid samples at the same time. Through LIBS identification, the coal fuel entering the furnace is subjected to elemental analysis to obtain the content of C / H / O / N / S / N elements in the biomass fuel.

[0074] Step S110 can also utilize a NOx concentration tester at the inlet of the SCR reactor to obtain in real time the NO concentration in the coal-fired flue gas output from the coal-fired unit to the inlet of the SCR reactor, that is, the inlet NO concentration of the SCR reactor.

[0075] Step S120, determining the minimum continuous ammonia injection operating temperature of the SCR reactor and the maximum deactivation time of the catalyst in the SCR reactor when the coal-fired unit operates at a typical low-load operating temperature under deep peak regulation conditions based on the sulfur content and the inlet NO concentration.

[0076] For example, step S120 may specifically include: determining the SO in the coal-fired flue gas generated by the coal-fired unit according to the sulfur content. 3 content; determine the amount of ammonia injected into the SCR reactor based on the inlet NO concentration; determine the amount of SO in the coal-fired flue gas based on the inlet NO concentration; determine the amount of ammonia injected into the SCR reactor .... 3 The minimum continuous ammonia injection operating temperature and the maximum deactivation time are determined by the content and the ammonia injection amount of the SCR reactor.

[0077] Specifically, step S120 can calculate the SO in the coal-fired flue gas generated by the coal-fired unit according to the following formula: 3 Content C SO3,in :

[0078]

[0079] Among them, S ar To input the sulfur content of the coal of the coal-fired unit, it can be obtained by online analysis and measurement using an element online analysis test device installed on the coal conveyor belt of the coal-fired unit. 烟气 V is the flue gas volume, which is a known parameter for the operation of coal-fired units. SO2,in SO in the flue gas generated by coal-fired units 2 Volume. C SO2,in SO in the flue gas generated by coal-fired units 2 ω is the sulfur conversion rate, which is also a known parameter for the operation of coal-fired units.

[0080] Of course, step S120 can also determine the SO in the coal-fired flue gas generated by the coal-fired unit according to the sulfur content of the coal input to the coal-fired unit in other ways. 3 The content is not limited in this embodiment.

[0081] Step S120 can also determine the amount of ammonia injected into the SCR reactor according to the following formula:

[0082] Ammonia injection amount = Q × C NOx,in ×NSR÷46×17÷1000000

[0083] NSR=η 设定 ÷100+3÷C NOx,in ×2.05

[0084]

[0085] Where Q represents the flue gas volume, in m 3 / h, which is a known operating parameter of a coal-fired unit. NOx,in Indicates the NOx concentration at the inlet of the SCR reactor, in mg / m 3, which can be measured by the NOx concentration test instrument installed at the inlet of the SCR reactor. NSR represents the ammonia nitrogen molar ratio. η 设定 Indicates denitrification efficiency in %. NOx,out,设定 Indicates the NOx concentration at the outlet of the SCR reactor.

[0086] Exemplarily, according to the sulfur trioxide content in the coal-fired flue gas and the ammonia injection amount of the SCR reactor, the minimum continuous ammonia injection operating temperature and the maximum deactivation time are determined respectively, including: according to Formula 1, the minimum continuous ammonia injection operating temperature is determined:

[0087] T mot =α×(C NH3,in ×C SO3,in ) β Formula 1.

[0088] Among them, T mot Indicates the minimum continuous ammonia injection operating temperature, C NH3,in Indicates the amount of ammonia injected into the SCR reactor, C SO3,in Indicates SO in coal-fired flue gas 3 content, α represents the first temperature coefficient, and β represents the second temperature coefficient. Both α and β are constants and can be determined by laboratory temperature tests.

[0089] Exemplarily, according to the sulfur trioxide content in the coal-fired flue gas and the ammonia injection amount of the SCR reactor, the minimum continuous ammonia injection operating temperature and the maximum deactivation time are determined respectively, and the maximum deactivation time is determined according to Formula 2:

[0090]

[0091] Among them, t represents the longest inactivation time, α t represents the first time coefficient, β t Represents the second time coefficient. α t With β t They are all constants and can be determined by testing the maximum allowable deactivation time at typical low load temperatures.

[0092] Specifically, when the typical low load under deep peak load regulation includes the deep load regulation range of 30% boiler maximum continuous evaporation capacity (BMCR) to 40% BMCR, if the operating temperature of the coal-fired unit at 30% BMCR is T min,1 , the operating temperature at 35% BMCR is T min,2 , the operating temperature at 40% BMCR is T min,3 , then the catalyst is at T min,1 , T min,2 , T min,3The longest deactivation running time under 1 ,t 2 ,t 3 ,and Among them, α 1 , α 2 , α 3 and β 1 , β 2 , β 3 They are all constants and can be determined by the maximum allowable deactivation time test at typical low load temperature.

[0093] Step S130, compare the minimum continuous ammonia injection operating temperature with the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions, and control the maximum duration of the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions and decide whether to open the temperature increase bypass based on the comparison result and the longest deactivation time.

[0094] Exemplarily, step S130 includes: if the coal-fired unit is operating at a typical low load operating temperature T under deep peak load conditions min Greater than or equal to the minimum continuous ammonia injection operating temperature T mot , that is, T min ≥T mot , indicating that the operating temperature of the coal-fired unit at this time is higher than the minimum continuous ammonia injection operating temperature. The coal-fired unit can operate continuously under the typical low-load condition under the current deep peak-shaving condition without opening the temperature-raising bypass. The coal-fired unit can operate economically. Therefore, the coal-fired unit is kept continuously operating at the typical low-load operating temperature under the deep peak-shaving condition, and the temperature-raising bypass is kept closed. If the coal-fired unit operates at the typical low-load operating temperature T under the deep peak-shaving condition, the temperature of the coal-fired unit is 0.18V. min Less than the minimum continuous ammonia injection operating temperature T mot , that is, T min <T mot , indicating that the operating temperature of the coal-fired unit at this time is lower than the minimum continuous ammonia injection operating temperature. The catalyst will be deactivated when the coal-fired unit is operated at this temperature. Therefore, in order to prevent the catalyst from being irreversibly deactivated, the coal-fired unit is kept operating at a typical low-load operating temperature T under deep peak regulation conditions. min Until the operating time reaches the maximum deactivation time t, and the coal-fired unit is operating at a typical low load operating temperature T under deep peak load conditions. min When the longest deactivation time reaches the longest deactivation time t, the temperature increase bypass is opened to increase the flue gas temperature at the SCR inlet to the minimum continuous ammonia injection operation temperature T mot At this time, the typical low-load operating temperature T of the coal-fired unit under deep peak load regulation in the prior art is min Less than the minimum continuous ammonia injection operating temperature T motCompared with directly opening the temperature-raising bypass, the operation time of the temperature-raising bypass can be shortened. The saved operation time of the temperature-raising bypass is the longest deactivation time t of the catalyst, and the coal-fired unit operates economically.

[0095] Compared with the prior art, the operation control method of the coal-fired unit provided in the embodiment of the present disclosure can obtain the sulfur content of the coal input into the coal-fired unit and the inlet NO concentration of the SCR reactor connected to the coal-fired unit in real time under typical low-load conditions of deep peak-shaving conditions. In addition, the time for putting the temperature-raising bypass into operation can be reasonably arranged in combination with the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions, thereby effectively reducing the degree of boiler efficiency reduction and improving the economy of the coal-fired unit operation.

[0096] Exemplarily, the operation control method of the coal-fired unit further includes: using a laboratory temperature test to determine the first temperature coefficient α and the second temperature coefficient β. The laboratory temperature test is described below.

[0097] Specifically, the laboratory temperature test includes: taking the first layer of catalyst in the SCR reactor as a catalyst sample; conducting a test in the laboratory, passing a test flue gas into the catalyst sample, and the flue gas condition of the test flue gas is NO+NH 3 +O 2 +SO 2 +SO 3 +CO 2 +H 2 O, among which NO and NH 3 The concentration ratio of NH in the flue gas condition is set to 1.0; 3 Concentration and SO 3 The concentrations were set to different values ​​to obtain multiple groups of flue gas data; based on each group of flue gas data, cooling tests and deactivation temperature tests were performed to obtain the minimum continuous ammonia injection operation temperature T corresponding to each group of flue gas data. mot ; The NH corresponding to each group of flue gas data 3 Concentration and SO 3 Concentration and its corresponding minimum continuous ammonia injection operating temperature T mot Substitute T mot =α×(C NH3,in ×C SO3,in ) β Perform data fitting to obtain specific values ​​of α and β.

[0098] The cooling test includes: keeping the test temperature T1 constant, testing for a preset time, and measuring the NO content and NH 3 content, according to the NO content and NH 3content, calculate the activity k of the catalyst sample at the test temperature T1 at the i-th moment i With the initial activity k 0 The ratio k i / k 0 , if k i / k 0 If it remains unchanged within the preset time, the test temperature T1 is gradually reduced and the cooling test is repeated until k is obtained. i / k 0 The test temperature during the drop is T2.

[0099] The deactivation temperature test includes: testing at the test temperature T2 for a preset time, increasing the test temperature T2 to the design normal operating temperature corresponding to the catalyst sample, testing again for a preset time, and calculating the activity k of the catalyst sample at the design normal operating temperature at the i-th moment. i With the initial activity k 0 The ratio k i / k 0 , if k i / k 0 If it gradually recovers to 1 within the preset time, the test temperature T2 is gradually reduced and the inactivation temperature test is repeated until k is obtained. i / k 0 The test temperature Tn when it cannot be restored, the previous test temperature Tn-1 of the test temperature Tn is used as the lowest continuous ammonia injection operating temperature T of the catalyst sample under the current flue gas data of the flue gas conditions. mot .

[0100] Exemplarily, the operation control method further includes: determining the first time coefficient α by using a maximum allowable deactivation time test at a typical low load temperature t and the second time coefficient β t The following is an explanation of the maximum allowable deactivation time test at typical low load temperatures.

[0101] Specifically, the maximum allowable deactivation time test at a typical low-load temperature includes: taking the first layer of catalyst in the SCR reactor as a catalyst sample; conducting a test in the laboratory, passing a test flue gas into the catalyst sample, and the flue gas condition of the test flue gas is NO+NH 3 +O 2 +SO 2 +SO 3 +CO 2 +H 2 O, among which NO and NH 3 The concentration ratio of NH in the flue gas condition is set to 1.0; 3 Concentration and SO 3The concentrations were set to different values ​​to obtain multiple groups of flue gas data; a deactivation time test was performed based on each group of flue gas data to obtain the longest deactivation time t of the catalyst sample under the typical low-load operating temperature under deep peak regulation conditions under each group of flue gas data; the NH 3 Concentration and SO 3 The concentration and its corresponding longest inactivation time t are substituted into Fit the data and get α t and β t The specific value of .

[0102] Exemplarily, the deactivation time test includes: setting the test temperature to the typical low-load operating temperature T of the coal-fired unit under deep peak regulation conditions. min Keep the test temperature constant, test for a specified time, and conduct NO and NH 3 The content test, according to the measured NO content and NH 3 content, calculate the activity k of the catalyst sample at the test temperature at the i-th moment i With the initial activity k 0 The ratio k i / k 0 , increase the test temperature to the normal operating temperature of the catalyst sample under typical low load conditions under deep peak regulation, and calculate k i / k 0 , if k i / k 0 If it can be restored to 1, the specified time will be gradually extended and the inactivation time test will be repeated until k is obtained. i / k 0 The specified time when recovery is impossible, the previous specified time of the specified time is used as the typical low-load operating temperature T of the catalyst sample under deep peak regulation conditions min The longest inactivation time t under .

[0103] It should be noted that the T in the above inactivation time test min Replace with T min,1 , T min,2 , T min,3 , then T can be obtained through the inactivation time test min,1 , T min,2 , T min,3 The corresponding longest inactivation time t 1 ,t 2 ,t 3 . Combined with the NH corresponding to each group of flue gas data 3 Concentration and SO 3 concentration, respectively, using

[0104] By fitting the data, we can get α 1 , α 2 , α 3 and β 1 , β 2 , β 3 The specific value of .

[0105] In order to enable those skilled in the art to better understand the above implementation, a specific example is used as an example for description below.

[0106] A method for controlling the operation of a coal-fired unit comprises the following steps:

[0107] The lowest continuous ammonia injection operating temperature T under multiple sets of flue gas data was obtained by using laboratory temperature tests and the longest allowable deactivation time test at typical low load temperatures. mot , the operating temperature of the catalyst in the coal-fired unit operating at 30% BMCR T min,1 The longest deactivation running time t 1 and the operating temperature T of the catalyst when the coal-fired unit is operating at 40% BMCR min,3 The longest deactivation running time t 3 , the specific data are shown in Table 1 below, where NH 3 (μL / L) indicates the NH in the test flue gas conditions 3 Concentration C NH3,in , is the test setting value. 3 (μL / L) indicates the SO in the test flue gas conditions 3 Concentration C SO3,in , is the test setting value. 3 ×SO 3 Indicates NH in the test flue gas conditions 3 Concentration and SO 3 The product of the concentrations.

[0108] Table 1 Test data

[0109] <![CDATA[NH 3 (μL / L)]]> <![CDATA[SO 3 (μL / L)]]> <![CDATA[NH 3 ×SO 3 ((μL / L) 2 )]]> <![CDATA[T mot (℃)]]> <![CDATA[t 1 (min)]]> <![CDATA[t 3 (min)]]> 70 9.1 636 287 360 560 80 10.2 816 290 300 480 90 10.3 927 292 250 400 100 11.3 1126 295 210 330 110 11.5 1265 296 196 270 120 12.3 1475 299 168 220 130 12.5 1623 300 137 190 140 16.8 2356 305 120 175

[0110] According to the data shown in Table 1, the formula T mot =α×(C NH3,in ×C SO3,in ) β , After data fitting, we get α = 208.95, β = 0.0489, α 1 =114426,β 1 =-0.894, α 3 =392781,β 3 =-1.013, so Tmot =208.95×(C NH3,in ×C SO3,in ) 0.0489 , t 1 =114426×(C NH3,in ×C SO3,in ) -0.894 , t 3 =392781×(C NH3,in ×C SO3,in ) -1.013 .

[0111] When the coal-fired unit is operated at 30% BMCR and the operating temperature is T min,1 =285℃, the sulfur content of the coal fed into the coal-fired unit and the NO concentration at the inlet of the SCR reactor connected to the coal-fired unit are obtained to determine the SO in the coal-fired flue gas. 3 Content C SO3,in =10μL / L, the amount of ammonia sprayed into the SCR reactor C NH3,in =100μL / L, substitute it into the formula T mot =208.95×(C NH3,in ×C SO3,in ) 0.0489 , calculate T mot =293℃, at this time, T min,1 <T mot , indicating that the operating temperature of the coal-fired unit at this time is lower than the minimum continuous ammonia injection temperature. min,1 The catalyst will be deactivated if the C SO3,in =10μL / L and C NH3,in =100μL / L Substitute into the formula t 1 =114426×(C NH3,in ×C SO3,in ) -0.894 , calculate the longest inactivation time t 1 = 238min, indicating that the coal-fired unit is running at T min,1 Although the catalyst deactivation occurred at 285℃, the coal-fired unit can operate at the operating temperature T min,1 = Run continuously at 285°C for 238 minutes, then open the temperature-raising bypass and the catalyst will regain activity.

[0112] When the coal-fired unit is operated at 40% BMCR and the operating temperature is T min,1 =292℃, the sulfur content of the coal fed into the coal-fired unit and the NO concentration at the inlet of the SCR reactor connected to the coal-fired unit are obtained to determine the SO in the coal-fired flue gas. 3 Content C SO3,in=10μL / L, the amount of ammonia sprayed into the SCR reactor C NH3,in =80μL / L, substitute it into the formula T mot =208.95×(C NH3,in ×C SO3,in ) 0.0489 , calculate T mot =290℃, at this time, T min,1 >T mot , indicating that the operating temperature of the coal-fired unit at this time is higher than the minimum continuous ammonia injection temperature. min,1 There will be no catalyst deactivation when operating under BMCR. Therefore, the coal-fired unit can operate at a temperature of T min,1 = 292℃ continuous operation, no need to open the temperature increase bypass, the coal-fired unit can operate economically.

[0113] Another embodiment of the present disclosure relates to an operation control device for a coal-fired unit, such as Figure 2 As shown, it includes an acquisition module 210, a determination module 220, and a control module 230.

[0114] The acquisition module 210 is used to acquire the sulfur content of the coal input to the coal-fired unit and the inlet NO concentration of the SCR reactor connected to the coal-fired unit.

[0115] The determination module 220 is used to determine the minimum continuous ammonia injection operating temperature of the SCR reactor and the maximum deactivation time of the catalyst in the SCR reactor when the coal-fired unit operates at a typical low-load operating temperature under deep peak-shaving conditions based on the sulfur content and the inlet NO concentration.

[0116] The control module 230 is used to compare the minimum continuous ammonia injection operating temperature with the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions, and control the maximum duration of the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions and decide whether to open the temperature increase bypass based on the comparison result and the maximum deactivation time.

[0117] Exemplarily, the operation control device of the coal-fired unit also includes a laboratory temperature test module.

[0118] The laboratory temperature test module is used to determine the first temperature coefficient and the second temperature coefficient by using the laboratory temperature test.

[0119] The laboratory temperature test includes: taking the first layer of catalyst in the SCR reactor as a catalyst sample; conducting a test in the laboratory, passing a test flue gas into the catalyst sample, and the flue gas condition of the test flue gas is NO+NH 3 +O 2 +SO 2 +SO 3 +CO2 +H 2 O, among which NO and NH 3 The concentration ratio of NH in the flue gas condition is set to 1.0; 3 Concentration and SO 3 The concentrations were set to different values ​​to obtain multiple groups of flue gas data; based on each group of flue gas data, cooling tests and deactivation temperature tests were performed to obtain the minimum continuous ammonia injection operation temperature T corresponding to each group of flue gas data. mot :The NH corresponding to each group of flue gas data 3 Concentration and SO 3 Concentration and its corresponding minimum continuous ammonia injection operating temperature T mot Substitute T mot =α×(C NH3,in ×C SO3,in ) β Perform data fitting to obtain specific values ​​of α and β.

[0120] Exemplarily, the operation control device of the coal-fired unit also includes a maximum allowable deactivation time test module under typical low load temperature.

[0121] The longest allowable deactivation time test module under typical low-load temperature is used to determine the first time coefficient and the second time coefficient by using the longest allowable deactivation time test under typical low-load temperature.

[0122] The test of the longest allowable deactivation time at a typical low-load temperature includes: taking the first layer of catalyst in the SCR reactor as a catalyst sample; conducting a test in the laboratory, and passing a test flue gas into the catalyst sample. The flue gas condition of the test flue gas is NO+NH 3 +O 2 +SO 2 +SO 3 +CO 2 +H 2 O, among which NO and NH 3 The concentration ratio of NH in the flue gas condition is set to 1.0; 3 Concentration and SO 3 The concentrations were set to different values ​​to obtain multiple groups of flue gas data; a deactivation time test was performed based on each group of flue gas data to obtain the longest deactivation time t of the catalyst sample under the typical low-load operating temperature under deep peak regulation conditions under each group of flue gas data; the NH 3 Concentration and SO 3 The concentration and its corresponding longest inactivation time t are substituted into Fit the data and get α t and β t The specific value of .

[0123] The specific implementation method of the operation control device of the coal-fired unit provided in the embodiment of the present disclosure can be referred to the operation control method of the coal-fired unit provided in the embodiment of the present disclosure, and will not be repeated here.

[0124] Compared with the prior art, the operation control device of the coal-fired unit provided in the embodiment of the present disclosure can obtain the sulfur content of the coal input into the coal-fired unit and the inlet NO concentration of the SCR reactor connected to the coal-fired unit in real time under typical low-load conditions of deep peak-shaving conditions, and can reasonably arrange the time for the temperature increase bypass to be put into use in combination with the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions, thereby effectively reducing the degree of boiler efficiency reduction and improving the economy of the coal-fired unit operation.

[0125] Those skilled in the art will appreciate that the above-mentioned embodiments are specific embodiments for implementing the present disclosure, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present disclosure.

Claims

1. A method for controlling the operation of a coal-fired unit, characterized in that: The operation control method comprises: Obtaining the sulfur content of the coal input into the coal-fired unit and the NO concentration at the inlet of the SCR reactor connected to the coal-fired unit; Determine, according to the sulfur content and the inlet NO concentration, the minimum continuous ammonia injection operating temperature of the SCR reactor and the maximum deactivation time of the catalyst in the SCR reactor when the coal-fired unit operates at a typical low-load operating temperature under deep peak-shaving conditions; The minimum continuous ammonia injection operating temperature is compared with the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions. Based on the comparison result and the maximum deactivation time, the maximum duration of the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions is controlled and it is decided whether to open the temperature increase bypass.

2. The operation control method according to claim 1, characterized in that: The step of determining the minimum continuous ammonia injection operating temperature of the SCR reactor and the maximum deactivation time of the catalyst in the SCR reactor when the coal-fired unit operates at a typical low-load operating temperature under deep peak-shaving conditions according to the sulfur content and the inlet NO concentration comprises: Determining the SO3 content in the coal-fired flue gas generated by the coal-fired unit according to the sulfur content; Determining the amount of ammonia injected into the SCR reactor according to the inlet NO concentration; The minimum continuous ammonia injection operating temperature and the maximum deactivation time are determined respectively according to the SO3 content in the coal-fired flue gas and the ammonia injection amount of the SCR reactor.

3. The operation control method according to claim 2, characterized in that: The step of determining the minimum continuous ammonia injection operation temperature and the maximum deactivation time according to the sulfur trioxide content in the coal-fired flue gas and the ammonia injection amount of the SCR reactor comprises: According to Formula 1, the minimum continuous ammonia injection operating temperature is determined: T mot =α×(C NH3,in ×C SO3,in ) β Formula 1; Among them, T mot Indicates the minimum continuous ammonia injection operating temperature, C NH3,in represents the amount of ammonia injected into the SCR reactor, C SO3,in represents the SO3 content in the coal-fired flue gas, α represents the first temperature coefficient, and β represents the second temperature coefficient.

4. The operation control method according to claim 3, characterized in that: The method of determining the minimum continuous ammonia injection operation temperature and the maximum deactivation time according to the sulfur trioxide content in the coal-fired flue gas and the ammonia injection amount of the SCR reactor respectively further includes: According to Formula 2, the maximum inactivation time is determined: Wherein, t represents the longest inactivation time, α t represents the first time coefficient, β t Represents the second time coefficient.

5. The operation control method according to claim 3, characterized in that: The operation control method further includes: Determine the first temperature coefficient and the second temperature coefficient by using a laboratory temperature test; The laboratory temperature test includes: Taking the first layer of catalyst in the SCR reactor as a catalyst sample; The test was conducted in the laboratory, and a test flue gas was introduced into the catalyst sample, wherein the test flue gas conditions were NO+NH3+O2+SO2+SO3+CO2+H2O, wherein the concentration ratio of NO to NH3 was set to 1.0; The NH3 concentration and SO3 concentration in the flue gas conditions are set to different values ​​to obtain multiple groups of flue gas data; Based on each group of flue gas data, a cooling test and a deactivation temperature test are performed respectively to obtain the minimum continuous ammonia injection operation temperature T corresponding to each group of flue gas data. mot ; The NH3 concentration and SO3 concentration corresponding to each group of flue gas data and their corresponding minimum continuous ammonia injection operation temperature T mot Substitute T mot =α×(C NH3,in ×C SO3,in )β is used to fit the data and obtain the specific values ​​of α and β.

6. The operation control method according to claim 5, characterized in that: The cooling test includes: keeping the test temperature T1 unchanged, testing for a preset time, measuring the NO content and NH3 content at the flue gas outlet of the catalyst sample, and calculating the activity k of the catalyst sample at the test temperature T1 at the i-th moment according to the NO content and the NH3 content. i The ratio k to the initial activity k0 i / k0, if k i / k0 remains unchanged within the preset time, the test temperature T1 is gradually reduced, and the temperature reduction test is repeated until k i / Test temperature T2 when k0 decreases; The deactivation temperature test includes: testing the preset time at the test temperature T2, increasing the test temperature T2 to the designed normal operating temperature corresponding to the catalyst sample, testing the preset time again, and calculating the activity k of the catalyst sample at the i-th moment at the designed normal operating temperature. i The ratio k to the initial activity k0 i / k0, if k i / k0 gradually recovers to 1 within the preset time, the test temperature T2 is gradually reduced, and the deactivation temperature test is repeated until k i / k0 is the test temperature Tn when it cannot be restored, and the previous test temperature Tn-1 of the test temperature Tn is used as the lowest continuous ammonia injection operation temperature T of the catalyst sample under the current flue gas data of the flue gas condition. mot .

7. The operation control method according to claim 4, characterized in that: The operation control method further includes: Determine the first time factor and the second time factor by using a maximum allowable deactivation time test at a typical low-load temperature; The test of the longest allowable deactivation time at the typical low load temperature includes: Taking the first layer of catalyst in the SCR reactor as a catalyst sample; The test was conducted in the laboratory, and a test flue gas was introduced into the catalyst sample, wherein the test flue gas conditions were NO+NH3+O2+SO2+SO3+CO2+H2O, wherein the concentration ratio of NO to NH3 was set to 1.0; The NH3 concentration and SO3 concentration in the flue gas conditions are set to different values ​​to obtain multiple groups of flue gas data; Based on each group of flue gas data, a deactivation time test is performed to obtain the longest deactivation time t of the catalyst sample under the typical low-load operating temperature under deep peak regulation conditions under each group of flue gas data; Substitute the NH3 concentration and SO3 concentration corresponding to each group of flue gas data and their corresponding longest deactivation time t into Fit the data and get α t and β t The specific value of .

8. The operation control method according to claim 7, characterized in that: The inactivation time test includes: The test temperature is set to the typical low-load operating temperature T of the coal-fired unit under deep peak regulation conditions. min ; Keep the test temperature unchanged, test for a specified time, test the NO and NH3 contents at the flue gas outlet of the catalyst sample, and calculate the activity k of the catalyst sample at the test temperature at the i-th moment based on the measured NO and NH3 contents. i The ratio k to the initial activity k0 i / k0, increase the test temperature to the normal operating temperature of the catalyst sample under the typical low load condition under deep peak regulation, and calculate k i / k0, if k i / k0 can be restored to 1, then gradually extend the specified time and repeat the deactivation time test until k is obtained. i / k0 is the specified time when it cannot be restored, and the previous specified time of the specified time is used as the typical low-load operating temperature T of the catalyst sample under deep peak regulation conditions min The longest inactivation time t under .

9. The operation control method according to any one of claims 1 to 8, characterized in that: The method of comparing the minimum continuous ammonia injection operating temperature with the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions, and controlling the maximum duration of the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions according to the comparison result and the maximum deactivation time, and determining whether to open the temperature-raising bypass, comprises: If the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions is greater than or equal to the minimum continuous ammonia injection operating temperature, the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions is maintained, and the temperature-raising bypass is kept closed; If the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions is lower than the minimum continuous ammonia injection operating temperature, the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions is maintained, and when the longest duration of the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions reaches the maximum deactivation time, the temperature raising bypass is opened to raise the flue gas temperature at the SCR inlet to the minimum continuous ammonia injection operating temperature.

10. An operation control device for a coal-fired unit, characterized in that: The operation control device comprises: An acquisition module, used to acquire the sulfur content of the coal input into the coal-fired unit and the inlet NO concentration of the SCR reactor connected to the coal-fired unit; A determination module, for determining, according to the sulfur content and the inlet NO concentration, a minimum continuous ammonia injection operating temperature of the SCR reactor and a maximum deactivation time of a catalyst in the SCR reactor when the coal-fired unit operates at a typical low-load operating temperature under deep peak-shaving conditions; A control module is used to compare the minimum continuous ammonia injection operating temperature with the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions, and control the maximum duration of the typical low-load operating temperature of the coal-fired unit under deep peak-shaving conditions and decide whether to open the temperature increase bypass based on the comparison result and the maximum deactivation time.

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