A wet desulfurization energy-saving control method and system

Abstract

The present invention discloses a wet flue gas desulfurization energy-saving control method, wherein at least one level in a multi-level spraying layer is provided with n partitions to form a partitioned spraying layer, and the n partitions are controlled to spray separately; the method comprises the following steps: simulating the flue gas parameters entering the tower under different working conditions in the wet flue gas desulfurization treatment, calculating the required slurry circulation amount and slurry supply amount under the current simulated working condition through material balance, and then calculating the opening combination of each slurry circulation pump of the multi-level spraying layer and each partition in the partitioned spraying layer according to the required slurry circulation amount, and obtaining the operation strategy under the current simulated working condition; forming a strategy library with different operation strategies calculated under different working conditions; when the absorption tower is in operation, selecting the optimal strategy that best matches the current working condition from the strategy library according to the flue gas parameters entering the tower under the actual operating condition; and operating with the optimal strategy to perform flue gas treatment. The present invention also provides a wet flue gas desulfurization energy-saving control system, which can reduce operating power consumption, save costs, and ensure flue gas treatment efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of flue gas treatment and relates to a wet desulfurization energy-saving control method and system. Background Art

[0002] my country is the world's largest coal producer and consumer. The main air pollutants produced by coal combustion are SO2, NO X , dust, etc., among which SO2 emissions rank first in the world. Limestone-gypsum wet flue gas desulfurization technology (W-FGD) is one of the most widely used pollution gas control technologies in coal-fired power plants. With the development of power construction and the continuous increase in installed capacity of power plants, the capacity of supporting equipment for wet desulfurization devices has also gradually increased. Its power consumption accounts for about 1% to 1.5% of the power generation of the unit, and the power consumption rate accounts for 20% of the plant's electricity consumption. Limestone-gypsum wet desulfurization devices are in urgent need of energy saving and consumption reduction, intelligent operation, and minimize power consumption and improve economic benefits while meeting environmental protection requirements.

[0003] The flue gas desulfurization device of a 2×660MW generator set of a company in Inner Mongolia adopts limestone-gypsum wet flue gas desulfurization process, with one furnace and one tower layout, and the desulfurization efficiency is ≥99%; its process system includes: limestone slurry preparation system, flue gas system, SO2 absorption system, gypsum dehydration system, process water system, emission system, wastewater treatment system, no booster fan, no GHH; among them, the limestone slurry preparation system, gypsum dehydration system, process water system, and wastewater treatment system are shared by two units. The power consumption statistics of each auxiliary machine and public system are as follows:

[0004] Power consumption rate (two units) Power consumption rate (one unit) Slurry circulation pump 76.2％ 69.2％ Oxidation fan 7.4％ 6.7％ Wet ball mill 6.4％ 5.8％ Public system 10％ 18.3％

[0005] From the table above, under the background of "50355" emission requirements, the improvement of desulfurization efficiency, the increase of liquid-gas ratio and the increase of spraying layers make the proportion of electric energy consumption of slurry circulation pump in limestone-gypsum wet desulfurization device increasingly larger, and its power consumption rate reaches more than 70%. Therefore, the optimization of spraying system and the intelligent energy saving of slurry circulation pump are of great significance to the consumption reduction of desulfurization device.

[0006] In view of the above technical problems, it is extremely necessary for those skilled in the art to provide a wet flue gas desulfurization energy-saving control method and system that reduces operating power consumption, saves costs, and ensures flue gas treatment efficiency. Summary of the invention

[0007] In order to solve the above technical problems, the purpose of the present invention is to provide a wet flue gas desulfurization energy-saving control method and system that reduces operating power consumption, saves costs, and ensures flue gas treatment efficiency.

[0008] One of the purposes of the present invention is to provide a wet flue gas desulfurization energy-saving control system, and the technical scheme adopted is as follows:

[0009] A wet flue gas desulfurization energy-saving control method, comprising an absorption tower connected to a slurry supply system, wherein a demister, a multi-stage spray layer, and a slurry pool are sequentially arranged in the absorption tower from top to bottom; a nozzle with an opening facing downward is arranged on each spray layer; the multi-stage spray layer is respectively connected to the slurry pool through a circulating spray pipe with a slurry circulation pump; characterized in that at least one of the multi-stage spray layers is provided with n partitions to form a partition spray layer, n is a positive integer and ≥2, and the n partitions are respectively connected to the slurry pool through the circulating spray pipe, so as to control the n partitions to spray separately;

[0010] The wet desulfurization energy-saving control method comprises the following steps:

[0011] Simulate the flue gas parameters entering the tower under different working conditions in wet flue gas desulfurization treatment, calculate the required slurry circulation volume and slurry supply volume under the current simulated working conditions through material balance, and then calculate the opening combination of each slurry circulation pump of the multi-stage spray layer and each partition in the partition spray layer according to the required slurry circulation volume, and obtain the operation strategy under the current simulated working conditions; different operation strategies calculated under different working conditions form a strategy library;

[0012] When the absorption tower is running, the optimal strategy that best matches the current operating conditions is selected from the strategy library according to the flue gas parameters entering the tower under the actual operating conditions;

[0013] Operate with optimal strategy for flue gas treatment.

[0014] Preferably, the slurry circulation pump on the circulating spray pipe corresponding to the partition spray layer is set as a variable frequency pump, the n partitions are respectively connected to the circulating spray pipe with the variable frequency pump through the spray branch, and the corresponding partition control valve for controlling whether to spray the corresponding partition is respectively arranged on each spray branch of each partition; the opening combination of each slurry circulation pump of the multi-stage spray layer and each partition in the partition spray layer is calculated according to the required slurry circulation amount: the number of slurry circulation pumps to be opened, the operating frequency of the variable frequency pump and the number of partition control valves to be opened are calculated according to the required slurry circulation amount;

[0015] Preferably, the slurry circulation pump corresponding to the partitioned spray layer includes n slurry circulation sub-pumps, and the n slurry circulation sub-pumps are respectively connected to the n partitions through circulating spray pipes; the opening combination of each slurry circulation pump of the multi-stage spray layer and each partition in the partitioned spray layer is calculated according to the required slurry circulation volume: according to the required slurry circulation volume, the number of slurry circulation pumps to be opened and the number of slurry circulation sub-pumps to be opened are calculated.

[0016] Preferably, after the operation with the optimal strategy and the flue gas treatment, the following steps are also included:

[0017] When the exhaust gas emission parameters exceed the standard, the strategy is changed from the strategy library.

[0018] Furthermore, after the operation with the optimal strategy and the flue gas treatment is performed, the following steps are also included:

[0019] When the outgoing flue gas parameters and / or slurry parameters are close to the limit values ​​and do not cause a change in strategy, the first operation or the second operation is executed, and the third operation is executed accordingly; the first operation is to adjust the number of slurry circulation pumps opened and / or the operating frequency of the variable frequency pump and the number of partition control valves opened to adjust the slurry circulation volume; the second operation is to adjust the number of slurry circulation pumps opened and / or the number of slurry circulation sub-pumps opened to adjust the slurry circulation volume; the third operation is to adjust the frequency of the slurry supply pump in the slurry supply system to adjust the slurry supply volume; by optimizing the operating strategy, stable and standard emissions of the outgoing flue gas are achieved; and the optimized operating strategy is stored in the strategy library.

[0020] Further, when the outgoing flue gas parameters and / or slurry parameters are close to the limit value and no strategy change is caused, the first operation or the second operation is performed, and the third operation is performed accordingly; the first operation is to adjust the number of openings of the slurry circulation pump and / or the operating frequency of the variable frequency pump and the number of openings of the partition control valve to adjust the slurry circulation volume; the second operation is to adjust the number of openings of the slurry circulation pump and / or the number of openings of the slurry circulation sub-pumps to adjust the slurry circulation volume; the third operation is to adjust the frequency of the slurry supply pump in the slurry supply system to adjust the slurry supply volume; by optimizing the operation strategy to achieve stable and standard emission of the outgoing flue gas:

[0021] When the SO2 concentration and / or slurry pH value of the flue gas out of the tower are close to the limit value and no strategy change is caused, the operating frequency of the variable frequency pump and the number of openings of the zone control valve are adjusted, or the number of openings of the slurry circulation sub-pumps are adjusted to adjust the slurry circulation volume, and the frequency of the slurry supply pump is adjusted accordingly to adjust the liquid-gas ratio and the slurry supply volume to reduce the SO2 concentration; when the frequency of the variable frequency pump reaches the maximum value and the SO2 concentration of the flue gas out of the tower is still close to the limit value, the number of openings of the spray layer is changed by adjusting the number of openings of the slurry circulation pump, and the frequency of the slurry supply pump is adjusted accordingly until the SO2 concentration is reduced, and the SO2 concentration of the flue gas out of the tower is stabilized and meets the emission standards by optimizing the operation strategy;

[0022] The optimized operation strategy is stored in the strategy library.

[0023] The second object of the present invention is to provide a wet flue gas desulfurization energy-saving control system, comprising an absorption tower connected to a variable frequency slurry supply pump in a slurry supply system, wherein the absorption tower is provided with a demister, a multi-stage spray layer, and a slurry pool in order from top to bottom; each spray layer is provided with a nozzle with an opening facing downward; the multi-stage spray layer is connected to the slurry pool through a circulating spray pipe with a slurry circulating pump; the characteristics are:

[0024] At least one level of the multi-level spraying layer is provided with n partitions to form a partitioned spraying layer, where n is a positive integer and is ≥ 2, and the n partitions are respectively connected to the slurry pool through a circulating spraying pipeline;

[0025] The wet desulfurization energy-saving control system also includes:

[0026] Desulfurization DCS control system;

[0027] The desulfurization DCS control system includes an instrument signal acquisition system; the instrument signal acquisition system includes a pH meter for monitoring the slurry parameters in the absorption tower, and a tower flue gas continuous monitoring system for monitoring the flue gas parameters at the tower, the flue gas parameters at the tower include flue gas flow, SO2 concentration, and dust concentration;

[0028] The desulfurization DCS control system is electrically connected to the multiple slurry circulation pumps corresponding to the multi-stage spraying layer, and is connected to the spraying control of the n partitions in the partition spraying layer, so as to control the opening and closing of the slurry circulation pump and / or each partition in the partition spraying layer; the desulfurization DCS control system is also electrically connected to the slurry supply pump, so as to adjust the slurry supply amount; so that the parameters of the flue gas out of the tower are continuously lower than the upper limit value;

[0029] Smart energy-saving module;

[0030] The smart energy-saving module is connected to the desulfurization DCS control system to simulate the flue gas parameters entering the tower under different working conditions, and calculate the slurry circulation volume and slurry supply volume required under the current simulated working conditions according to the material balance, and then calculate the opening combination of each slurry circulation pump of the multi-stage spray layer and each partition in the partition spray layer according to the required slurry circulation volume, obtain the operation strategy under the current simulated working condition, transmit the operation strategy to the desulfurization DCS control system, and store the different operation strategies obtained under different working conditions in the storage medium to form a strategy library;

[0031] It is also used to analyze the operating parameters of the flue gas entering the tower, and recommend the optimal strategy that best matches the current operating parameters from the strategy library to the desulfurization DCS control system based on the operating parameters.

[0032] Preferably, the slurry circulation pump on the circulating spray pipeline corresponding to the partition spray layer is set as a variable frequency pump, and the n partitions are connected to the circulating spray pipeline with a variable frequency pump through the spray branch respectively, and a partition control valve for controlling whether to spray the corresponding partition is respectively arranged on each spray branch corresponding to each partition; the variable frequency pump and the partition control valve are electrically connected to the desulfurization DCS control system; the intelligent energy-saving module is used to calculate the number of slurry circulation pump openings, the operating frequency of the variable frequency pump and the number of partition control valve openings according to the required slurry circulation volume, and transmit operation instructions to the desulfurization DCS control system;

[0033] Preferably, the slurry circulation pump corresponding to the partitioned spray layer includes n slurry circulation sub-pumps, and the n slurry circulation sub-pumps are respectively connected to the n partitions through circulating spray pipes; the n slurry circulation sub-pumps are electrically connected to the desulfurization DCS control system; the intelligent energy-saving module is used to calculate the number of slurry circulation pumps and slurry circulation sub-pumps to be opened according to the required slurry circulation volume, and transmit operating instructions to the desulfurization DCS control system.

[0034] Preferably, the intelligent energy-saving module is also used to replace the strategy from the strategy library of the storage medium when receiving the signal of excessive flue gas emissions from the desulfurization DCS control system, and transmit the replaced strategy to the desulfurization DCS control system.

[0035] Furthermore, the wet flue gas desulfurization energy-saving control system further includes: a strategy optimization module;

[0036] The strategy optimization module is electrically connected to the desulfurization DCS control system, and is used to receive slurry parameters and / or outflowing flue gas parameters and compare them with the limit values ​​set in the desulfurization DCS control system. If the outflowing flue gas parameters and / or slurry parameters are close to the limit values ​​and do not cause a strategy change, an operation instruction to execute the first operation or the second operation and the third operation is transmitted to the desulfurization DCS control system accordingly; wherein the first operation is to adjust the number of slurry circulation pumps opened and / or the operating frequency of the variable frequency pump and the number of partition control valves opened to adjust the slurry circulation volume; the second operation is to adjust the number of slurry circulation pumps opened and / or the number of slurry circulation sub-pumps opened to adjust the slurry circulation volume; the third operation is to adjust the frequency of the slurry supply pump in the slurry supply system to adjust the slurry supply volume; stable and standard emission of outflowing flue gas is achieved by optimizing the operation strategy;

[0037] The strategy optimization module is also connected to the smart energy-saving module by electrical signals, and is used to store the optimized operation strategy in a storage medium to update the strategy library.

[0038] Furthermore, the continuous monitoring system for flue gas entering and exiting the tower includes a SO2 concentration detector;

[0039] The strategy optimization module is used to receive the SO2 concentration of the flue gas out of the tower and / or the pH value of the slurry and compare them with the limit set in the desulfurization DCS control system. If the SO2 concentration of the flue gas out of the tower and / or the pH value of the slurry is close to or exceeds the limit and does not cause a change in the strategy, an instruction is sent to the desulfurization DCS control system to control and adjust the operating frequency of the variable frequency pump and the number of openings of the partition control valve, or adjust the number of openings of the slurry circulation sub-pump to adjust the slurry circulation volume, and adjust the frequency of the slurry supply pump accordingly to adjust the liquid-gas ratio and the slurry supply volume to reduce the SO2 concentration; if the frequency of the variable frequency pump reaches the maximum value and the SO2 concentration of the flue gas out of the tower is still close to the limit, an instruction is sent to the desulfurization DCS control system to adjust the number of openings of the slurry circulation pump to change the number of opening layers of the spray layer, and adjust the frequency of the slurry supply pump accordingly until the SO2 concentration is reduced, and the SO2 concentration of the flue gas out of the tower is stabilized and meets the emission standards by optimizing the operation strategy.

[0040] The present invention can bring the following beneficial effects:

[0041] 1) In the present invention, by partitioning at least one level in the multi-level spraying layer and controlling the spraying of each partition separately, the spraying layer can realize the operation mode combining the number of multi-level operation layers with the number of n-level operation partitions, which can save the electric energy of the wet flue gas desulfurization system. In addition, a strategy library storing a large number of strategies can be established for different simulation conditions, so that in actual operation, the closest strategy can be selected as the optimal strategy according to the change of flue gas conditions very conveniently and efficiently to improve the processing efficiency.

[0042] 2) The zoned spray control in the present invention can be set in two forms. A zoned control valve is set corresponding to the n zones of the zoned spray layer and connected to the slurry circulation pipeline with a variable frequency pump, or a slurry circulation pipeline with a smaller slurry circulation sub-pump with flow rate is set corresponding to each zone. Therefore, under the premise of meeting the standards of wet treatment of flue gas, the energy-saving operation of the slurry circulation pump is achieved by adjusting the frequency of the variable frequency pump and controlling the start and stop of the zoned control valve on each zone of the spray layer, or by the number of slurry circulation sub-pumps opened, so that the spray layer can achieve an operation mode combining multiple operating layers with n-level operating zones, which can save about 10-15% of the electric energy of the wet flue gas desulfurization system, reduce the use of slurry supply, and save more costs.

[0043] 3) In the control method of the present invention, by simulating the change of working conditions, the slurry circulation amount and slurry supply amount required under the current simulated working conditions are calculated through material balance, and then the opening combination of each slurry circulation pump in the multi-stage spray layer and each partition in the partition spray layer is calculated according to the required slurry circulation amount, and the operation strategy under the current simulated working conditions is obtained; the different operation strategies calculated under different working conditions form a strategy library to guide the desulfurization operation; during the actual operation, according to the flue gas parameters entering the tower under the actual operating conditions, the optimal strategy that best matches the current working conditions is screened from the strategy library; the optimal strategy is operated to treat the flue gas. After the operation is carried out with the optimal strategy, because the flue gas working conditions are constantly changing, the relevant Continuous monitoring of parameters (such as SO2 concentration in flue gas and pH value of slurry). For example, when the parameter SO2 concentration is close to the set control limit and does not cause a change in strategy, the slurry circulation volume and slurry supply volume can be adjusted by adjusting the frequency of the variable frequency pump, the number of zone control valves opened, and the frequency of the slurry supply pump, thereby fine-tuning the liquid-gas ratio; when the frequency of the variable frequency pump is adjusted to the maximum and the effect is still not good, more levels of spray layers can be re-commissioned to further adjust the liquid-gas ratio to ensure that the SO2 concentration meets the emission standards, and the optimized operation strategy is stored in the strategy library, thereby realizing intelligent monitoring of flue gas treatment, automatic analysis and adjustment of strategies, and updating, to ensure that the flue gas treatment operates in an energy-saving manner while meeting the standards.

[0044] 4) The present invention establishes a strategy library that can store a large number of strategies, and can select the closest strategy as the optimal strategy for operation according to the changes in flue gas conditions; the operating personnel can also adjust the operating strategy according to their own experience, and can realize manual and automatic dual control modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 The present invention is a flow chart of an embodiment of the wet flue gas desulfurization energy-saving control method.

[0046] Figure 2 This is a flow chart of another embodiment of the wet flue gas desulfurization energy-saving control method of the present invention.

[0047] Figure 3 The present invention is a flow chart of another embodiment of the wet desulfurization energy-saving control method.

[0048] Figure 4 It is a structural schematic diagram (including circuit connection) of an embodiment of the wet flue gas desulfurization energy-saving control system of the present invention.

[0049] Figure 5 It is a structural schematic diagram (including circuit connection) of another embodiment of the wet flue gas desulfurization energy-saving control system of the present invention.

[0050] Figure 6a A schematic diagram of an embodiment of the partition spray layer of the present invention in which partitions A and B are set for simultaneous spraying.

[0051] Figure 6b for Figure 6a Spray diagram of middle partition A.

[0052] Figure 6c for Figure 6a Spray diagram of middle zone B.

[0053] Figure 7a A schematic diagram of another embodiment of the partition spray layer of the present invention in which partitions A and B are set for simultaneous spraying.

[0054] Figure 7b for Figure 7a Spray diagram of middle partition A.

[0055] Figure 7c for Figure 7a Spray diagram of middle zone B.

[0056] Description of Figure Numbers:

[0057] 1-absorption tower; 2-oxidation fan; 3-slurry supply pump; 4-gypsum discharge pump; 5-stirring device;

[0058] 6-slurry circulation pump, 60-circulation spray pipe, 6a-frequency conversion pump, 6b-slurry circulation sub-pump;

[0059] 7-spray layer, 7a-partition spray layer, 7aa-spray main pipe, 7ab-spray branch pipe, 70-spray branch, 71-nozzle;

[0060] 8-Zone control valve; 9-Defogger, 10-Desulfurization DCS control system. DETAILED DESCRIPTION

[0061] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0062] In order to simplify the drawings, each figure only schematically shows the parts related to the present invention, which do not represent the actual structure of the product.

[0063] One embodiment of the present invention, as Figure 1As shown, a wet flue gas desulfurization energy-saving control method comprises an absorption tower 1 connected to a slurry supply system, wherein the absorption tower 1 is provided with a demister 9, a multi-stage spray layer 7, and a slurry pool from top to bottom; a nozzle 71 with an opening facing downward is provided on each spray layer 7; the slurry pool is connected to the spray layer 7 through a circulating spray pipe 60 with a slurry circulating pump 6;

[0064] At least one level of the multi-level spraying layer 7 is provided with n partitions to form a partitioned spraying layer 7a, where n is a positive integer and is ≥ 2, and the n partitions are respectively connected to the slurry pool through a circulating spraying pipeline 60, so as to control the n partitions to spray separately;

[0065] The wet desulfurization energy-saving control method comprises the following steps:

[0066] S100 simulates the flue gas parameters entering the tower under different working conditions in wet flue gas desulfurization treatment, and calculates the required slurry circulation volume and slurry supply volume under the current simulated working conditions through material balance. Then, based on the required slurry circulation volume, it calculates the opening combination of each slurry circulation pump of the multi-stage spray layer and each partition in the partition spray layer to obtain the operating strategy under the current simulated working conditions; different operating strategies calculated under different working conditions form a strategy library.

[0067] Specifically, the flue gas parameters entering the tower under different working conditions (flue gas flow rate, SO2 concentration change, etc.) in the simulated wet flue gas desulfurization treatment can be calculated according to the material balance. The slurry circulation volume and slurry supply volume required under the current simulated working conditions can be calculated. Combined with the actual circulation flow rate of the slurry circulation pump at rated power and the circulation flow design parameters of each partition, the slurry circulation pumps set one by one in the corresponding multi-stage spray layer and the opening combination of each partition in the partition spray layer are calculated, so that the combined circulation flow rate is equal to or very close to the required slurry circulation volume. Thus, the operation strategy under the current simulated working conditions is obtained; the different operation strategies calculated under different working conditions form a strategy library.

[0068] When the S200 absorption tower is in operation, the optimal strategy that best matches the current operating conditions is selected from the strategy library based on the flue gas parameters entering the tower under actual operating conditions.

[0069] Specifically, the flue gas parameters entering the tower under actual operating conditions are compared with the flue gas parameters of simulated conditions in the strategy library, and the closest simulated conditions are screened out, and the strategy corresponding to the simulated conditions is used as the optimal strategy for the current flue gas conditions.

[0070] S300 operates with the optimal strategy for flue gas treatment.

[0071] Specifically, the optimal values ​​of the slurry circulation volume and slurry supply volume are given in the strategy library, and the desulfurization system is controlled to operate according to the optimal strategy.

[0072] In this embodiment, by partitioning at least one level in the multi-level spraying layer and controlling the spraying of each partition separately, the spraying layer can realize the operation mode combining the multi-level operation layer number with the n-level operation partition number, which can save about 10-15% of the electric energy of the wet flue gas desulfurization system and save the slurry supply. In addition, a strategy library storing a large number of strategies can be established for different simulation conditions, so that in actual operation, the closest strategy can be selected as the optimal strategy according to the change of flue gas conditions very conveniently and efficiently to improve the processing efficiency.

[0073] As a preferred solution, in this embodiment, two different partition spraying control methods for the partition spraying layer are preferably provided:

[0074] The first implementation method, such as Figure 4 As shown:

[0075] The slurry circulation pump on the circulating spray pipe 60 corresponding to the partition spray layer 7a is set as a variable frequency pump 6a, and the n partitions are respectively connected to the circulating spray pipe 60 with the variable frequency pump 6a through the spray branch 70, and each spray branch 70 corresponding to each partition is respectively provided with a partition control valve 8 for controlling whether to spray the corresponding partition.

[0076] The control method for energy-saving wet flue gas desulfurization of the present invention adopts the variable frequency design of the slurry circulation pump combined with the differentiated design of the spray layer, so that during operation, the appropriate combination of the industrial frequency slurry circulation pump and the zoned spraying can be selected according to the actual working conditions, without running all the industrial frequency slurry circulation pumps at full power, thereby saving electric energy while ensuring the treatment effect.

[0077] Accordingly, the wet flue gas desulfurization energy-saving control method includes the following steps:

[0078] S101 simulates the flue gas parameters entering the tower under different working conditions in wet flue gas desulfurization treatment, and calculates the required slurry circulation volume and slurry supply volume under the current simulated working conditions through material balance. Then, the number of slurry circulation pump openings, the operating frequency of the variable frequency pump and the number of zone control valves opened are calculated based on the required slurry circulation volume, and the operating strategy under the current simulated working conditions is obtained; different operating strategies calculated under different working conditions form a strategy library.

[0079] Specifically, by simulating the flue gas parameters entering the tower under different working conditions in the wet flue gas desulfurization treatment, the required slurry circulation volume and slurry supply volume under the current simulated working conditions can be calculated based on the material balance. Combined with the circulation flow rate of the slurry circulation pump actually used at the rated power and the circulation flow design parameters of each zone, the number of times the slurry circulation pump is opened, as well as the operating frequency of the variable frequency pump and the number of times the zone control valve is opened are calculated, so that the combined circulation flow rate is equal to or very close to the required slurry circulation volume; thereby, the operating strategy under the current simulated working conditions is obtained; different operating strategies calculated under different working conditions form a strategy library.

[0080] When the S200 absorption tower is in operation, the optimal strategy that best matches the current operating conditions is selected from the strategy library based on the flue gas parameters entering the tower under actual operating conditions.

[0081] Specifically, the flue gas parameters entering the tower under actual operating conditions are compared with the flue gas parameters of simulated conditions in the strategy library, and the closest simulated conditions are screened out, and the strategy corresponding to the simulated conditions is used as the optimal strategy for the current flue gas conditions.

[0082] S300 operates with the optimal strategy for flue gas treatment.

[0083] Specifically, the optimal values ​​of the slurry circulation volume and slurry supply volume are given in the strategy library, and the desulfurization system is controlled to operate according to the optimal strategy.

[0084] The second implementation method, such as Figure 5 As shown:

[0085] The slurry circulation pump 6 corresponding to the partitioned spray layer 7a includes n slurry circulation sub-pumps 6b, and the n slurry circulation sub-pumps 6b are respectively connected to the n partitions through the circulating spray pipes 60; therefore, the circulation flow of the slurry circulation sub-pump 6b is 1 / n of the maximum slurry circulation flow of the partitioned spray layer.

[0086] The control method for energy-saving wet flue gas desulfurization of the present invention adopts a small-scale industrial frequency design of the slurry circulation pump combined with a differentiated design of the spray layer. For example, when the number of partitions is set to 2, the corresponding two slurry circulation sub-pumps 6b are each a small industrial frequency pump with a circulation flow of 50%, so that during operation, a suitable combination of a large-flow slurry circulation pump and a small-flow industrial frequency slurry circulation sub-pump for partition spraying can be selected according to actual working conditions, without the need for all large-flow slurry circulation pumps to operate at full power, thereby saving electric energy while ensuring the treatment effect.

[0087] Accordingly, the wet flue gas desulfurization energy-saving control method includes the following steps:

[0088] S102 simulates the flue gas parameters entering the tower under different working conditions in the wet flue gas desulfurization treatment, and calculates the required slurry circulation volume and slurry supply volume under the current simulated working conditions through material balance. Then, based on the required slurry circulation volume, the number of times the slurry circulation pump 6 is opened and the number of times the slurry circulation sub-pump 6b is opened are calculated to obtain the operating strategy under the current simulated working conditions; different operating strategies calculated under different working conditions form a strategy library.

[0089] Specifically, the flue gas parameters entering the tower under different working conditions in the wet flue gas desulfurization treatment are simulated, and the slurry circulation volume and slurry supply volume required under the current simulated working conditions can be calculated based on the material balance. Combined with the circulation flow rate of the slurry circulation pump actually used at the rated power and the circulation flow rate design parameters of each partition, the number of slurry circulation pumps 6 opened and the number of slurry circulation sub-pumps 6b opened are calculated to make the combined circulation flow rate equal to or very close to the required slurry circulation volume; thereby, the operating strategy under the current simulated working conditions is obtained; different operating strategies calculated under different working conditions form a strategy library.

[0090] When the S200 absorption tower is in operation, the optimal strategy that best matches the current operating conditions is selected from the strategy library based on the flue gas parameters entering the tower under actual operating conditions.

[0091] Specifically, the flue gas parameters entering the tower under actual operating conditions are compared with the flue gas parameters of simulated conditions in the strategy library, and the closest simulated conditions are screened out, and the strategy corresponding to the simulated conditions is used as the optimal strategy for the current flue gas conditions.

[0092] S300 operates with the optimal strategy for flue gas treatment.

[0093] Specifically, the optimal values ​​of the slurry circulation volume and slurry supply volume are given in the strategy library, and the desulfurization system is controlled to operate according to the optimal strategy.

[0094] Another embodiment of the present invention, as Figure 2 As shown, a wet flue gas desulfurization energy-saving control method comprises an absorption tower 1 connected to a slurry supply system, wherein the absorption tower 1 is provided with a demister 9, a multi-stage spray layer 7, and a slurry pool from top to bottom; a nozzle 71 with an opening facing downward is provided on each spray layer 7; the slurry pool is connected to the spray layer 7 through a circulating spray pipe 60 with a slurry circulating pump 6;

[0095] At least one level of the multi-level spraying layer 7 is provided with n partitions to form a partitioned spraying layer, where n is a positive integer and is ≥ 2, and the n partitions are respectively connected to the slurry pool through a circulating spraying pipeline 60, so as to control the n partitions to spray separately;

[0096] The wet desulfurization energy-saving control method comprises the following steps:

[0097] S100 simulates the flue gas parameters entering the tower under different working conditions in wet flue gas desulfurization treatment, and calculates the required slurry circulation volume and slurry supply volume under the current simulated working conditions through material balance. Then, based on the required slurry circulation volume, it calculates the opening combination of each slurry circulation pump of the multi-stage spray layer and each partition in the partition spray layer to obtain the operating strategy under the current simulated working conditions; different operating strategies calculated under different working conditions form a strategy library.

[0098] Specifically, the flue gas parameters entering the tower under different working conditions in the wet flue gas desulfurization treatment are simulated, and the slurry circulation volume and slurry supply volume required under the current simulated working conditions can be calculated based on the material balance. Combined with the circulation flow rate of the slurry circulation pump actually used at the rated power and the circulation flow rate design parameters of each partition, the opening combination of each slurry circulation pump in the multi-stage spray layer and each partition in the partition spray layer is calculated, so that the combined circulation flow rate is equal to or very close to the required slurry circulation volume, and the frequency of the slurry supply pump in the slurry supply system is adjusted accordingly to provide the corresponding slurry circulation volume; thus, the operating strategy under the current simulated working conditions is obtained; the different operating strategies calculated under different working conditions form a strategy library. In addition, if Figure 3 As shown, step S100 may adopt any implementation of step S101 or step S102 in the previous embodiment.

[0099] When the S200 absorption tower is in operation, the optimal strategy that best matches the current operating conditions is selected from the strategy library based on the flue gas parameters entering the tower under actual operating conditions.

[0100] Specifically, the flue gas parameters entering the tower under actual operating conditions are compared with the flue gas parameters of simulated conditions in the strategy library, and the closest simulated conditions are screened out, and the strategy corresponding to the simulated conditions is used as the optimal strategy for the current flue gas conditions.

[0101] S300 operates with the optimal strategy for flue gas treatment.

[0102] Specifically, the optimal values ​​of slurry circulation volume and slurry supply volume are given in the strategy library, and the desulfurization system is controlled to operate according to this strategy.

[0103] When the exhaust gas emission parameters of S400 tower exceed the standard, the strategy is replaced from the strategy library and then run again.

[0104] In this embodiment, not only can a strategy library storing a large number of strategies be established for different simulation conditions, but in actual operation, the closest strategy can be selected as the optimal strategy according to the changes in flue gas conditions very conveniently and efficiently to improve processing efficiency. At the same time, the strategy can be replaced after operation to ensure that the flue gas emissions meet the standards and the desulfurization treatment can operate efficiently and stably.

[0105] Another embodiment of the present invention, as Figure 3As shown, a wet desulfurization energy-saving control method comprises the following steps:

[0106] S101 / S102 simulates the flue gas parameters entering the tower under different working conditions in the wet flue gas desulfurization treatment, and calculates the required slurry circulation volume and slurry supply volume under the current simulated working conditions through material balance, and then calculates the number of times the slurry circulation pump is opened according to the required slurry circulation volume, as well as the operating frequency of the variable frequency pump and the number of times the partition control valve is opened, or calculates the number of times the slurry circulation pump 6 is opened and the number of times the slurry circulation sub-pump 6b is opened according to the required slurry circulation volume, and obtains the operating strategy under the current simulated working conditions; different operating strategies calculated under different working conditions form a strategy library.

[0107] Specifically, the flue gas parameters entering the tower under different working conditions in the wet flue gas desulfurization treatment are simulated, and the slurry circulation amount and slurry supply amount required under the current simulated working conditions can be calculated based on the material balance. Combined with the circulation flow rate of the slurry circulation pump 6 actually used at the rated power and the circulation flow design parameters of each partition, the number of times the slurry circulation pump is opened, the operating frequency of the variable frequency pump and the number of times the partition control valve is opened are calculated, or the number of times the slurry circulation pump 6 is opened and the number of times the slurry circulation sub-pump 6b is opened are calculated, so that the combined circulation flow rate is equal to or very close to the required slurry circulation amount, and the frequency of the slurry supply pump in the slurry supply system is adjusted accordingly to provide the corresponding slurry circulation amount; thereby, the operating strategy under the current simulated working conditions is obtained; different operating strategies calculated under different working conditions form a strategy library.

[0108] When the S200 absorption tower is in operation, the optimal strategy that best matches the current operating conditions is selected from the strategy library based on the flue gas parameters entering the tower under actual operating conditions.

[0109] Specifically, the flue gas parameters entering the tower under actual operating conditions are compared with the flue gas parameters of simulated conditions in the strategy library, and the closest simulated conditions are screened out, and the strategy corresponding to the simulated conditions is used as the optimal strategy for the current flue gas conditions.

[0110] S300 operates with the optimal strategy for flue gas treatment.

[0111] Specifically, the optimal values ​​of the slurry circulation volume and slurry supply volume are given in the strategy library, and the desulfurization system is controlled to operate according to the optimal strategy.

[0112] S410 When the outgoing flue gas parameters and / or slurry parameters are close to the limit values ​​and do not cause a change in strategy, execute the first operation or the second operation, and execute the third operation accordingly; the first operation is to adjust the number of slurry circulation pump 6 openings and / or the operating frequency of the variable frequency pump 6a and the number of partition control valves 8 openings to adjust the slurry circulation volume; the second operation is to adjust the number of slurry circulation pump 6 openings and / or the number of slurry circulation sub-pumps 6b openings to adjust the slurry circulation volume; the third operation is to adjust the frequency of the slurry supply pump in the slurry supply system to adjust the slurry supply volume; by optimizing the operating strategy, stable and standard emissions of the outgoing flue gas are achieved; and the optimized operating strategy is stored in the strategy library.

[0113] Specifically, when the parameter is close to or has exceeded the standard, generally when it is close to the minimum limit value of the exceeding standard, the corresponding operation will be performed to control the outlet concentration. The liquid-gas ratio can be changed by adjusting the corresponding slurry circulation volume to improve the flue gas treatment capacity; and on this basis, according to the difference in SO2 concentration of the flue gas entering and leaving the tower, the frequency of the slurry supply pump in the slurry supply system is adjusted accordingly to adjust the slurry supply amount. While ensuring that the flue gas leaving the tower meets the emission standards, the slurry supply amount is adjusted. On the basis of saving electricity, the pulping raw material limestone powder is saved. Specifically, the slurry supply amount is linearly related to the difference in SO2 concentration of the flue gas entering and leaving the tower. This is a commonly used method for adjusting the slurry supply amount in the prior art and will not be described in detail here.

[0114] Preferably, when the SO2 concentration and / or slurry pH value of the flue gas out of the tower are close to the limit value and no strategy change is caused, the operating frequency of the frequency conversion pump and the opening number of the zone control valve are adjusted, or the opening number of the slurry circulation sub-pump is adjusted to adjust the slurry circulation volume, and the frequency of the slurry supply pump is adjusted accordingly to adjust the liquid-gas ratio and the slurry supply volume to reduce the SO2 concentration; when the frequency of the frequency conversion pump reaches the maximum value, and the SO2 concentration of the flue gas out of the tower is still close to the limit value, the opening number of the spray layer is changed by adjusting the opening number of the slurry circulation pump until the SO2 concentration is reduced, and the SO2 concentration of the flue gas out of the tower is stabilized and meets the emission standards by optimizing the operation strategy; the optimized operation strategy is stored in the strategy library.

[0115] In this preferred solution, the SO2 concentration limit in the flue gas out of the tower can be used as an indicator; a control limit is set according to the indicator. When the SO2 concentration of the flue gas out of the tower is close to the control limit, the first operation or the second operation is performed, and the third operation is performed accordingly to provide the actual required slurry circulation amount to adjust the flue gas out of the tower. For example, the national standard requires that the maximum SO2 concentration of the flue gas out of the tower is 35mg / Nm 3 , set the control limit to 32mg / Nm 3 When the outlet SO2 concentration is detected to be close to 32mg / Nm 3 When adjusting (increasing) the liquid-gas ratio, adjust (increase) the slurry supply, and reduce the outlet SO2 concentration by optimizing the operation strategy.

[0116] In this embodiment, a strategy library of a large number of strategies can be stored, and the strategy closest to the working condition is selected as the optimal strategy for operation according to the flue gas changes. After operation, because the flue gas working condition is constantly changing, when the emission parameters of the flue gas out of the tower, such as SO2 concentration and slurry pH value, are close to or exceed the limit value, the slurry parameters in the absorption tower 1 can be dynamically adjusted. For example, the opening number of the partition control valve and the frequency of the variable frequency pump, or the opening number of the slurry circulation sub-pump can be adjusted, and the frequency of the slurry supply pump 3 can be adjusted accordingly, so as to fine-tune the liquid-gas ratio and the slurry supply amount to ensure that the flue gas out of the tower is always discharged up to standard. In addition, the optimized strategy can also be used to update the strategy library to gradually improve the operating efficiency. Thereby, intelligent monitoring of flue gas treatment, automatic analysis, adjustment, optimization and updating of strategies can be realized, and energy-saving operation of flue gas treatment can be ensured under the premise of meeting the standards.

[0117] Another embodiment of the present invention, as Figure 4 , 5 As shown, a wet flue gas desulfurization energy-saving control system includes an absorption tower 1 connected to a variable frequency slurry supply pump 3 in a slurry supply system, wherein the absorption tower 1 is provided with a demister 9, a multi-stage spray layer 7, and a slurry pool from top to bottom; a nozzle 71 with an opening facing downward is provided on each spray layer 7; the slurry pool is connected to the spray layer 7 through a circulating spray pipe 60 with a slurry circulating pump 6;

[0118] At least one level of the multi-level spraying layer 7 is provided with n partitions to form a partitioned spraying layer, where n is a positive integer and is ≥ 2, and the n partitions are respectively connected to the slurry pool through a circulating spraying pipeline 60, so as to control the n partitions to spray separately;

[0119] The wet desulfurization energy-saving control system also includes:

[0120] Desulfurization DCS control system 10;

[0121] The desulfurization DCS control system 10 includes an instrument signal acquisition unit; the instrument signal acquisition unit includes a pH meter for monitoring the slurry parameters in the absorption tower, and a flue gas continuous monitoring unit for monitoring the flue gas parameters at the tower and the tower, and the flue gas parameters at the tower and the tower include flue gas flow rate, SO2 concentration, and dust concentration;

[0122] The desulfurization DCS control system 10 is electrically connected to the multiple slurry circulation pumps 6 corresponding to the multi-stage spray layer 7, and is connected to the spray control of the n partitions in the partition spray layer, so as to control the opening and closing of the slurry circulation pump 6 and / or each partition in the partition spray layer; the desulfurization DCS control system 10 is also electrically connected to the slurry supply pump, so as to adjust the slurry supply amount; so that the parameters of the flue gas out of the tower are continuously lower than the upper limit value;

[0123] Smart energy-saving module;

[0124] The smart energy-saving module is connected to the desulfurization DCS control system 10, and is used to simulate the flue gas parameters entering the tower under different working conditions, and calculate the slurry circulation volume and slurry supply volume required under the current simulated working conditions according to the material balance, and then calculate the opening combination of each slurry circulation pump of the multi-stage spray layer and each partition in the partition spray layer according to the required slurry circulation volume, and obtain the operation strategy under the current simulated working condition, and transmit the operation strategy to the desulfurization DCS control system, and store the different operation strategies obtained under different working conditions in the storage medium to form a strategy library;

[0125] It is also used to analyze the operating parameters of the flue gas entering the tower, and recommend the optimal strategy that best matches the current operating parameters from the strategy library to the desulfurization DCS control system based on the operating parameters.

[0126] In this embodiment, the intelligent energy-saving module can establish a strategy library and recommend the optimal strategy, which is convenient for the efficient, stable and energy-saving operation of the wet flue gas desulfurization control system and can save the slurry supply. The slurry supply system connected to the inlet of the slurry supply pump 3 is a limestone slurry system, and the outlet of the slurry supply pump 3 is connected to the absorption tower 1.

[0127] Specifically, the desulfurization DCS control system in the present invention is an instrument control system commonly used in wet desulfurization treatment, and an ABL-pH-201 desulfurization DCS control system can be used; wherein a flue gas continuous monitoring unit (CEMS) is integrated, including a flue gas flow transmitter, a SO2 concentration detector, a dust concentration monitor, a pressure transmitter, a temperature transmitter, an encoder, various relays, and other equipment that can be used to monitor flue gas parameters. Other desulfurization DCS control systems that can monitor and control the process in wet desulfurization provided by manufacturers such as Hollysys, Zhejiang University Central Control, and Zhejiang Xinhua can also be used, which are not described one by one here.

[0128] Among them, preferably Figure 4 As shown, the slurry circulation pump on the circulation spray pipeline 60 corresponding to the partition spray layer 7a is set as a variable frequency pump 6a, and the n partitions are respectively connected to the circulation spray pipeline 60 with the variable frequency pump 6a through the spray branch 70, and the corresponding partitions are respectively provided with a partition control valve 8 for controlling whether to spray the corresponding partition; the variable frequency pump 6a and the partition control valve 8 are both electrically connected to the desulfurization DCS control system 10;

[0129] The intelligent energy-saving module is used to calculate the number of slurry circulation pumps to be opened, the operating frequency of the variable frequency pump and the number of zone control valves to be opened according to the required slurry circulation volume, and transmit operating instructions to the desulfurization DCS control system 10.

[0130] Therefore, when the zone spray control method adopts the combination of variable frequency pump and zone control valve, the slurry can calculate the combined opening method of the slurry circulation pump, variable frequency pump and zone control valve through the intelligent energy-saving module, and send instructions to the desulfurization DCS control system 10 for operation.

[0131] As another preferred embodiment, Figure 5 For example, the slurry circulation pump corresponding to the partition spray layer 7a includes n slurry circulation sub-pumps 6b, and the n slurry circulation sub-pumps 6b are respectively connected to the n partitions through the circulation spray pipeline 60; the n slurry circulation sub-pumps 6b are electrically connected to the desulfurization DCS control system 10;

[0132] The intelligent energy-saving module is used to calculate the number of slurry circulation pumps to be opened and the number of slurry circulation sub-pumps to be opened according to the required slurry circulation volume, and transmit operating instructions to the desulfurization DCS control system 10.

[0133] Therefore, when the zoned spray control method adopts a slurry circulation sub-pump with a smaller flow rate, the intelligent energy-saving module can calculate the combined opening method of the slurry circulation pump and the slurry circulation sub-pump, and send instructions to the desulfurization DCS control system 10 for operation.

[0134] As another preferred embodiment, the intelligent energy-saving module is also used to replace the strategy from the strategy library of the storage medium when receiving the signal of excessive flue gas emissions from the desulfurization DCS control system 10, and transmit the replaced strategy to the desulfurization DCS control system 10.

[0135] Therefore, the strategy can be replaced through the intelligent energy-saving module, so that the desulfurization DCS control system 10 can operate with the replaced strategy and the exhaust gas parameters can meet the emission standards.

[0136] As another preferred implementation, it also includes a strategy optimization module (not shown in the figure);

[0137] The strategy optimization module is electrically connected to the desulfurization DCS control system 10, and is used to receive slurry parameters and / or tower flue gas parameters and compare them with the limit values ​​set in the desulfurization DCS control system. If the tower flue gas parameters and / or slurry parameters are close to or exceed the limit values ​​and do not cause a strategy change, an operation instruction to execute the first operation or the second operation and the third operation is transmitted to the desulfurization DCS control system 10; the first operation is to adjust the number of slurry circulation pumps 6 opened and / or the operating frequency of the variable frequency pump 6a and the number of partition control valves 8 opened to adjust the slurry circulation volume; the second operation is to adjust the number of slurry circulation pumps 6 opened and / or the number of slurry circulation sub-pumps 6b opened to adjust the slurry circulation volume; the third operation is to adjust the frequency of the slurry supply pump 3 in the slurry supply system to adjust the slurry supply volume; stable and standard emission of tower flue gas is achieved by optimizing the operation strategy;

[0138] The strategy optimization module is also connected to the smart energy-saving module by electrical signals, and is used to store the optimized operation strategy in a storage medium to update the strategy library.

[0139] More preferably, the continuous monitoring system for flue gas entering and exiting the tower includes a SO2 concentration detector;

[0140] The strategy optimization module is used to receive the SO2 concentration of the flue gas out of the tower and / or the pH value of the slurry and compare them with the limit set in the desulfurization DCS control system. If the SO2 concentration of the flue gas out of the tower and / or the pH value of the slurry are close to the limit and no strategy change is caused, an instruction is sent to the desulfurization DCS control system to control and adjust the operating frequency of the variable frequency pump and the number of openings of the partition control valve, or adjust the number of openings of the slurry circulation sub-pump to adjust the slurry circulation volume, and adjust the frequency of the slurry supply pump accordingly to adjust the liquid-gas ratio and the slurry supply volume to reduce the SO2 concentration; if the frequency of the variable frequency pump reaches the maximum value and the SO2 concentration of the flue gas out of the tower is still close to the limit, an instruction is sent to the desulfurization DCS control system to adjust the number of openings of the slurry circulation pump to change the number of opening layers of the spray layer, and adjust the frequency of the slurry supply pump accordingly to increase the slurry supply until the SO2 concentration is reduced. By optimizing the operation strategy, the SO2 concentration of the flue gas out of the tower is stabilized and meets the emission standards.

[0141] Therefore, the strategy optimization module of the present invention can construct a desulfurization optimization strategy under different operating conditions by analyzing parameters such as outlet SO2 concentration and slurry pH value, output the slurry supply compensation value, and perform continuous optimization according to the parameter conditions.

[0142] As another preferred embodiment, the wet flue gas desulfurization control system further includes an oxidation fan 2, a gypsum discharge pump 4, and a stirring device 5;

[0143] The outlet of the oxidation fan 2 is connected to the absorption tower 1; the inlet of the gypsum discharge pump 4 is connected to the absorption tower 1, and the outlet of the gypsum discharge pump 4 is connected to the gypsum dehydration system; a stirring device 5 is arranged in the slurry pool at the bottom of the absorption tower 1.

[0144] As another preferred embodiment, the partitioned spray layer 7a includes n spray main pipes 7aa corresponding to the n partitions in the absorption tower 1, the n spray main pipes 7aa in the absorption tower 1 are arranged in parallel, and a plurality of spray branch pipes 7ab are arranged on any spray main pipe 7aa at intervals along the pipe length; the nozzles 71 of the plurality of spray branch pipes 7ab are arranged in a sunken cross-arrangement; the n spray main pipes 7aa are respectively connected to the slurry pool through the circulating spray pipe 60.

[0145] In this embodiment, another spray setting method can also be adopted. Specifically: the partitioned spray layer 7a includes n symmetrical spray main pipes 7aa correspondingly arranged outside the absorption tower 1, and any spray main pipe 7aa extends into the absorption tower 1 through a plurality of spray branch pipes 7ab arranged at intervals along the pipe length to form n partitions; the nozzles 71 of the plurality of spray branch pipes 7ab are arranged in a downward cross-arrangement; the n spray main pipes 7aa are connected to the slurry pool through the circulating spray pipe 60 respectively.

[0146] Thus, this embodiment provides a specific implementation method of zoned spraying, where n zones are formed by n spray main pipes 7aa, and each spray main pipe 7aa sprays through multiple spray branch pipes 7ab spaced along its pipe length, combined with the corresponding multiple spray branch pipes 7ab arranged in a downward cross-arranged manner. The spray coverage rate of each zone is higher when working at the same time, so as to improve the flue gas treatment capacity. Preferably, the spray branch pipes 7ab are evenly spaced in a direction perpendicular to the spray main pipe 7aa to obtain a greater spray coverage rate.

[0147] As another preferred embodiment, the spray coverage rate of any partition in the partition spray layer 7a is above 150%, and multiple spray coverage rates can be obtained when the partitions work simultaneously to ensure that the treated flue gas meets the emission standards.

[0148] like Figure 6a , 6b As shown in , 6c or 7a, 7b, 7c, the single-stage partition spray layer 7a is provided with two partitions, namely, partition A and partition B. In actual operation, under the premise of ensuring the coverage rate, according to the actual required slurry circulation volume, the partition operation of the single-stage partition spray layer 7a can open one partition corresponding to 50% of the slurry circulation volume, or open two partitions corresponding to 100% of the slurry circulation volume. Through the combination of the slurry circulation pump 6 and the opening of each partition in the partition spray layer 7a, the slurry circulation volume reaches the required amount for material balance, ensuring energy-saving operation and saving slurry supply.

[0149] In addition, it should be noted that during the flue gas treatment process, the desulfurization DCS control system 10 continuously identifies the exhaust gas emission parameters of the tower, and an adjustment strategy can be manually selected from the strategy library of the smart energy-saving module according to the parameter conditions.

[0150] Therefore, the present invention utilizes the intelligent energy-saving module to establish a strategy library that can store a large number of strategies, and can automatically select the closest strategy as the optimal strategy for operation according to changes in flue gas conditions; operators can also adjust the operation strategy according to their own experience, thereby realizing manual and automatic dual control modes.

[0151] The present invention also provides an application example, taking the actual parameters of flue gas desulfurization of a single 600MW unit in a domestic power plant as an example, the inlet flue gas volume of the limestone-gypsum wet desulfurization system of the project is 2139010Nm 3 / h (standard, wet, actual oxygen), inlet SO2 concentration 2415mg / Nm 3 The designed outlet SO2 concentration is 35mg / Nm 3 , desulfurization efficiency ≥98.6%, the system is equipped with four spray layers, corresponding to slurry circulation pumps #1~#4, the parameters are as follows:

[0152] Serial number <![CDATA[Flow rate (m 3 / h)]]> Rated power(Kw) Shaft power(Kw) #1 Slurry circulation pump 8300 800 670 #2 Slurry circulation pump 8300 900 748 #3 Slurry circulation pump 8300 900 812 #4 Slurry circulation pump 8300 1120 960

[0153] According to the control system and control method provided by the present invention, one layer of the spray system is changed to partition operation. Taking the #4 slurry circulation pump as an example, the modified slurry circulation pump is set to 2 partitions. The 2 partitions are respectively connected to the slurry pool circulation spray by 2 slurry circulation sub-pumps 6b with smaller flow rates, namely #4 slurry circulation sub-pump A and #4 slurry circulation sub-pump B. The parameters are as follows:

[0154] Serial number <![CDATA[Flow rate (m 3 / h)]]> Rated power(Kw) Shaft power(Kw) Remark #4 Slurry circulation sub-pump A 4150 560 480 Control system of the present invention #4 Slurry circulation sub-pump B 4150 560 480 Control system of the present invention

[0155] When the limestone-gypsum wet desulfurization system is in operation, the combination of the slurry circulation pump can be changed according to the change of the unit load (different flue gas conditions). The original system has four pumps, and 15 combinations can be realized. However, because the flow rate of each pump is the same, the flow rate combination is 4 in total, which is an integer multiple of the flow rate of a single slurry circulation pump; however, by using the technical solution of the present invention, one pump can be replaced with two slurry circulation sub-pumps with small flow rates, and the corresponding spray layer can be divided into two levels, thereby increasing the combination of pumps and the combination of flow rates, and 26 pump combinations and 8 flow rate combinations can be realized, as follows:

[0156]

[0157] When the boiler is operating at 80% flue gas load, through material balance calculation and historical data analysis, the required slurry circulation volume is 28000m 3 / h, which is greater than 24900m3 when three slurry circulation pumps are in operation 3 / h, less than 332000m3 when four pumps are running 3 / h. Under this working condition, only three circulation layers plus one partition of the #4 circulation layer (one slurry circulation sub-pump) need to be turned on to meet the circulation volume requirement, saving 460Kwh of electricity per hour.

[0158] By using the control system and control method of the present invention, the total power consumption can be reduced by 10% to 15% and the total limestone consumption by 10%.

[0159] It should be noted that the above embodiments can be freely combined as needed. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention.

Claims

1. A wet flue gas desulfurization energy-saving control method, comprising an absorption tower connected to a slurry supply system, wherein a demister, a multi-stage spray layer, and a slurry pool are arranged in sequence from top to bottom in the absorption tower; a nozzle with an opening facing downward is arranged on each spray layer; the multi-stage spray layer is connected to the slurry pool through a circulating spray pipeline with a slurry circulation pump; characterized in that: At least one level of the multi-level spraying layer is provided with n partitions to form a partitioned spraying layer, where n is a positive integer and is ≥ 2, and the n partitions are respectively connected to the slurry pool through circulating spraying pipes to control the n partitions to spray separately; The wet desulfurization energy-saving control method comprises the following steps: Simulate the flue gas parameters entering the tower under different working conditions in wet flue gas desulfurization treatment, calculate the required slurry circulation volume and slurry supply volume under the current simulated working conditions through material balance, and then calculate the opening combination of each slurry circulation pump of the multi-stage spray layer and each partition in the partition spray layer according to the required slurry circulation volume, and obtain the operation strategy under the current simulated working conditions; different operation strategies calculated under different working conditions form a strategy library; When the absorption tower is running, the optimal strategy that best matches the current operating conditions is selected from the strategy library according to the flue gas parameters entering the tower under the actual operating conditions; Operate with optimal strategy for flue gas treatment.

2. The wet flue gas desulfurization energy-saving control method according to claim 1, characterized in that: The slurry circulation pump on the circulation spray pipeline corresponding to the partition spray layer is set as a variable frequency pump, and the n partitions are respectively connected to the circulation spray pipeline with the variable frequency pump through the spray branch, and each spray branch corresponding to each partition is respectively provided with a partition control valve for controlling whether to spray the corresponding partition; the opening combination of each slurry circulation pump of the multi-stage spray layer and each partition in the partition spray layer is calculated according to the required slurry circulation amount: the number of slurry circulation pumps to be opened, the operating frequency of the variable frequency pump and the number of partition control valves to be opened are calculated according to the required slurry circulation amount; or; The slurry circulation pump corresponding to the partitioned spray layer includes n slurry circulation sub-pumps, and the n slurry circulation sub-pumps are connected to the n partitions through circulating spray pipes respectively; the opening combination of each slurry circulation pump of the multi-stage spray layer and each partition in the partitioned spray layer is calculated according to the required slurry circulation volume: the number of slurry circulation pumps to be opened and the number of slurry circulation sub-pumps to be opened are calculated according to the required slurry circulation volume.

3. The wet flue gas desulfurization energy-saving control method according to claim 1, characterized in that: After the above-mentioned operation with the optimal strategy and the flue gas treatment, the following steps are also included: When the exhaust gas emission parameters exceed the standard, the strategy is changed from the strategy library.

4. The wet flue gas desulfurization energy-saving control method according to claim 2, characterized in that: After the above-mentioned operation with the optimal strategy and the flue gas treatment, the following steps are also included: When the outflowing flue gas parameters and / or slurry parameters are close to the limit values ​​and do not cause a change in strategy, the first operation or the second operation is executed, and the third operation is executed accordingly; the first operation is to adjust the number of slurry circulation pumps opened and / or the operating frequency of the variable frequency pump and the number of partition control valves opened to adjust the slurry circulation volume; the second operation is to adjust the number of slurry circulation pumps opened and / or the number of slurry circulation sub-pumps opened to adjust the slurry circulation volume; the third operation is to adjust the frequency of the slurry supply pump in the slurry supply system to adjust the slurry supply volume; By optimizing the operation strategy, the stable emission of flue gas out of the tower can be achieved; the optimized operation strategy is stored in the strategy library.

5. The wet flue gas desulfurization energy-saving control method according to claim 4, characterized in that: When the outgoing flue gas parameters and / or slurry parameters are close to the limit value and no strategy change is caused, the first operation or the second operation is performed, and the third operation is performed accordingly; the first operation is to adjust the number of openings of the slurry circulation pump and / or the operating frequency of the variable frequency pump and the number of openings of the partition control valve to adjust the slurry circulation volume; the second operation is to adjust the number of openings of the slurry circulation pump and / or the number of openings of the slurry circulation sub-pumps to adjust the slurry circulation volume; the third operation is to adjust the frequency of the slurry supply pump in the slurry supply system to adjust the slurry supply volume; by optimizing the operation strategy to achieve stable and standard emission of the outgoing flue gas: When the SO2 concentration and / or slurry pH value of the flue gas out of the tower are close to the limit value and no strategy change is caused, the operating frequency of the variable frequency pump and the number of openings of the zone control valve are adjusted, or the number of openings of the slurry circulation sub-pumps are adjusted to adjust the slurry circulation volume, and the frequency of the slurry supply pump is adjusted accordingly to adjust the liquid-gas ratio and the slurry supply volume to reduce the SO2 concentration; when the frequency of the variable frequency pump reaches the maximum value and the SO2 concentration of the flue gas out of the tower is still close to the limit value, the number of openings of the spray layer is changed by adjusting the number of openings of the slurry circulation pump, and the frequency of the slurry supply pump is adjusted accordingly until the SO2 concentration is reduced, and the SO2 concentration of the flue gas out of the tower is stabilized and meets the emission standards by optimizing the operation strategy; The optimized operation strategy is stored in the strategy library.

6. A wet flue gas desulfurization energy-saving control system, comprising an absorption tower connected to a variable frequency slurry supply pump in a slurry supply system, wherein the absorption tower is provided with a demister, a multi-stage spray layer, and a slurry pool in order from top to bottom; each spray layer is provided with a nozzle with an opening facing downward; the multi-stage spray layer is connected to the slurry pool through a circulating spray pipe with a slurry circulating pump; characterized in that: At least one level of the multi-level spraying layer is provided with n partitions to form a partitioned spraying layer, where n is a positive integer and is ≥ 2, and the n partitions are respectively connected to the slurry pool through a circulating spraying pipeline; The wet desulfurization energy-saving control system also includes: Desulfurization DCS control system; The desulfurization DCS control system includes an instrument signal acquisition unit; the instrument signal acquisition unit includes a pH meter for monitoring the slurry parameters in the absorption tower, and a flue gas continuous monitoring unit for monitoring the flue gas parameters at the tower and the tower, and the flue gas parameters at the tower and the tower include flue gas flow, SO2 concentration, and dust concentration; The desulfurization DCS control system is electrically connected to the multiple slurry circulation pumps corresponding to the multi-stage spraying layer, and is connected to the spraying control of the n partitions in the partition spraying layer, so as to control the opening and closing of the slurry circulation pump and / or each partition in the partition spraying layer; the desulfurization DCS control system is also electrically connected to the slurry supply pump, so as to adjust the slurry supply amount; so that the parameters of the flue gas out of the tower are continuously lower than the upper limit value; Smart energy-saving module; The smart energy-saving module is connected to the desulfurization DCS control system to simulate the flue gas parameters entering the tower under different working conditions, and calculate the slurry circulation volume and slurry supply volume required under the current simulated working conditions according to the material balance, and then calculate the opening combination of each slurry circulation pump of the multi-stage spray layer and each partition in the partition spray layer according to the required slurry circulation volume, obtain the operation strategy under the current simulated working condition, transmit the operation strategy to the desulfurization DCS control system, and store the different operation strategies obtained under different working conditions in the storage medium to form a strategy library; It is also used to analyze the operating parameters of the flue gas entering the tower, and recommend the optimal strategy that best matches the current operating parameters from the strategy library to the desulfurization DCS control system based on the operating parameters.

7. The wet flue gas desulfurization energy-saving control system according to claim 6 is characterized in that: The slurry circulation pump on the circulating spray pipeline corresponding to the partition spray layer is set as a variable frequency pump, and the n partitions are connected to the circulating spray pipeline with the variable frequency pump through the spray branch respectively, and the corresponding partitions are respectively provided with a partition control valve for controlling whether to spray the corresponding partition; the variable frequency pump and the partition control valve are electrically connected to the desulfurization DCS control system; the intelligent energy-saving module is used to calculate the number of slurry circulation pumps to be opened, the operating frequency of the variable frequency pump and the number of partition control valves to be opened according to the required slurry circulation volume, and transmit operation instructions to the desulfurization DCS control system; The slurry circulation pump corresponding to the partitioned spray layer includes n slurry circulation sub-pumps, which are respectively connected to the n partitions through circulating spray pipes; the n slurry circulation sub-pumps are electrically connected to the desulfurization DCS control system; the intelligent energy-saving module is used to calculate the number of slurry circulation pumps and slurry circulation sub-pumps to be opened according to the required slurry circulation volume, and transmit operating instructions to the desulfurization DCS control system.

8. The wet flue gas desulfurization energy-saving control system according to claim 6, characterized in that: The intelligent energy-saving module is also used to replace the strategy from the strategy library of the storage medium when receiving the signal of excessive flue gas emissions from the desulfurization DCS control system, and transmit the replaced strategy to the desulfurization DCS control system.

9. The wet flue gas desulfurization energy-saving control system according to claim 7, characterized in that: Also includes: Strategy optimization module; The strategy optimization module is electrically connected to the desulfurization DCS control system, and is used to receive slurry parameters and / or outflowing flue gas parameters and compare them with the limit values ​​set in the desulfurization DCS control system. If the outflowing flue gas parameters and / or slurry parameters are close to the limit values ​​and do not cause a strategy change, an operation instruction to execute the first operation or the second operation and the third operation is transmitted to the desulfurization DCS control system accordingly; wherein the first operation is to adjust the number of slurry circulation pumps opened and / or the operating frequency of the variable frequency pump and the number of partition control valves opened to adjust the slurry circulation volume; the second operation is to adjust the number of slurry circulation pumps opened and / or the number of slurry circulation sub-pumps opened to adjust the slurry circulation volume; the third operation is to adjust the frequency of the slurry supply pump in the slurry supply system to adjust the slurry supply volume; stable and standard emission of outflowing flue gas is achieved by optimizing the operation strategy; The strategy optimization module is also connected to the smart energy-saving module by electrical signals, and is used to store the optimized operation strategy in a storage medium to update the strategy library.

10. The wet flue gas desulfurization energy-saving control system according to claim 9, characterized in that: The continuous monitoring system for flue gas entering and exiting the tower includes a SO2 concentration detector; The strategy optimization module is used to receive the SO2 concentration of the flue gas out of the tower and / or the pH value of the slurry and compare them with the limit set in the desulfurization DCS control system. If the SO2 concentration of the flue gas out of the tower and / or the pH value of the slurry are close to the limit and no strategy change is caused, an instruction is sent to the desulfurization DCS control system to control and adjust the operating frequency of the variable frequency pump and the number of openings of the partition control valve, or adjust the number of openings of the slurry circulation sub-pump to adjust the slurry circulation volume, and adjust the frequency of the slurry supply pump accordingly to adjust the liquid-gas ratio and the slurry supply volume to reduce the SO2 concentration; if the frequency of the variable frequency pump reaches the maximum value and the SO2 concentration of the flue gas out of the tower is still close to the limit, an instruction is sent to the desulfurization DCS control system to adjust the number of openings of the slurry circulation pump to change the number of opening layers of the spray layer, and adjust the frequency of the slurry supply pump accordingly until the SO2 concentration is reduced, and the SO2 concentration of the flue gas out of the tower is stabilized and meets the emission standards by optimizing the operation strategy.

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