An ultra-low emission desulfurization energy-saving operation system based on full-process sulfur monitoring

Abstract

The present invention discloses an ultra-low emission desulfurization energy-saving operation system based on full-process monitoring of sulfur, including an online coal quality monitoring device, a sulfur dioxide feedback device, and a circulating pump coupling adjustment and control device. The desulfurization energy-saving operation system is mainly used in the desulfurization system of a coal-fired power plant. First, the element content of the coal entering the furnace is directly detected by the coal quality element rapid detection device of the coal quality monitoring device, and the amount of sulfur dioxide that will enter the system is predicted by setting the program and formula calculation in the system, and then the judgment and control software of the circulating pump coupling adjustment and control system is used to adjust the start and stop of the circulating pump in advance. Finally, the online monitoring value of the desulfurization outlet is read, and the feedback is checked by the sulfur dioxide feedback system to realize the energy-saving operation of the desulfurization system.

Description

Technical Field

[0001] The invention relates to a desulfurization energy-saving operation under ultra-low emission conditions based on full-process monitoring of sulfur, and belongs to the technical field of flue gas treatment. Background Art

[0002] The desulfurization system is the system with the highest energy consumption in the post-furnace environmental protection system of coal-fired power plants, accounting for 1%-1.5% of the power consumption of the plant. Among them, the circulating pump is the main power consumer, accounting for more than half of the total desulfurization power consumption. In 2015, three ministries and commissions issued a document requiring coal-fired power plants to achieve ultra-low emissions. Most desulfurization devices use a large liquid-to-gas ratio to wash sulfur dioxide. During the transformation, the efficiency is improved by adding circulating pumps or expanding the capacity of circulating pumps. The energy consumption of desulfurization devices in ultra-low emissions has increased significantly.

[0003] In the ultra-low transformation design, the circulating pump is configured with full load and designed coal quality. In actual operation, full load conditions are rare, and coal quality also varies, so the circulating pump has a large margin in operation and there is room for energy saving. Reasonable use of the operating combination of the circulating pump can effectively achieve desulfurization and energy saving.

[0004] In the ultra-low emission operation of coal-fired power plants, the energy-saving means of desulfurization is achieved by manually shutting down the circulation pump. During operation, the circulation pump is started and stopped according to the sulfur dioxide value measured by the desulfurization inlet CEMS and operating experience, and the sulfur dioxide value measured by the outlet CEMS is controlled at 35mg / Nm 3 However, due to the unpredictability of coal quality changes and the amount of sulfur dioxide entering the system, there is always a large margin, making it impossible to achieve optimal energy-saving operation. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides an ultra-low emission desulfurization energy-saving operation system based on full-process monitoring of sulfur, and selects the combined operation mode of the circulating pump by predicting the amount of sulfur dioxide entering the system in advance.

[0006] In order to achieve the above-mentioned purpose, the technical scheme proposed in the present invention is: an ultra-low emission desulfurization energy-saving operation system based on full-process monitoring of sulfur, which is used in the desulfurization system of a coal-fired power plant, wherein the desulfurization system includes a boiler, a coal feeder arranged in front of the boiler, a desulfurization tower arranged behind the boiler, and a plurality of circulating pumps arranged on the desulfurization tower; the desulfurization energy-saving operation system includes a coal quality detection device and a circulating pump coupling adjustment and control device, wherein the coal quality detection device is arranged on the coal feeder, and the circulating pump coupling adjustment and control device includes a calculation module and a circulating pump control module connected to each other, wherein the circulating pump control module is connected to the circulating pump, and the coal quality detection device is connected to the calculation module, and is used to detect the coal information of the coal entering the furnace, and transmit the coal information to the calculation module; the calculation module is used to calculate the operating parameters such as the flue gas volume and sulfur dioxide volume entering the desulfurization system, and transmit the operating parameters to the circulating pump control module, wherein the circulating pump control module pre-stores a plurality of operating parameters and the circulating pump operating combination mode corresponding to the operating parameters, and the circulating pump control module obtains the optimal operating combination mode of the circulating pump by comparing the received operating parameters with the pre-stored operating parameters, and controls the start and stop of the circulating pump.

[0007] A further design of the above technical solution is as follows: the circulating pump coupling adjustment and control device also includes a protection module, which is connected to the circulating pump control module and is provided with a safe operation number of the circulating pump. When the number of circulating pumps turned on in the optimal operation combination mode of the circulating pump is less than the safe operation number, the protection module can control the number of circulating pumps turned on to be the safe operation number through the circulating pump control module.

[0008] The desulfurization system is provided with an outlet sulfur dioxide set value. The calculation module is also used to calculate the outlet sulfur dioxide value of the desulfurization system according to the optimal operation combination mode of the circulation pump, and compare the calculated outlet sulfur dioxide value of the desulfurization system with the set value, and transmit the comparison result to the circulation pump control module. The circulation pump control module adjusts the circulation pump operation combination mode according to the comparison result; the above operation is repeated until the deviation is minimized, and the circulation pump operation combination mode at this time is the optimal operation combination mode of the circulation pump.

[0009] The desulfurization energy-saving operation system also includes a sulfur dioxide feedback device, which includes a desulfurization system outlet CEMS. The desulfurization system outlet CEMS is used to monitor the sulfur dioxide value at the desulfurization system outlet and transmit it to the calculation module. The calculation module compares the monitored sulfur dioxide value at the desulfurization system outlet with the set value, and transmits the comparison result to the circulation pump control module. The circulation pump control module adjusts the circulation pump operation combination mode according to the comparison result; repeat the above operation until the outlet sulfur dioxide value is equal to or less than the set value, and the circulation pump operation combination mode at this time is the optimal circulation pump operation combination mode.

[0010] The coal quality detection device comprises a coal quality detector and a moisture meter, and the coal quality detector and the moisture meter are used to detect the sulfur content and moisture content of the coal entering the furnace respectively.

[0011] The coal quality detection device also includes a parameter acquisition module, which is used to collect the coal consumption of the desulfurization system and the operating parameters of the desulfurization system, and transmit the coal consumption and the operating parameters to the calculation module.

[0012] The desulfurization system parameters include pH value, slurry density, limestone input, etc.

[0013] The beneficial effects of the present invention are:

[0014] The present invention calculates the amount of sulfur dioxide in the flue gas entering the desulfurization system by detecting the sulfur content, moisture content and coal combustion amount of the incoming coal, thereby selecting the operation mode of the circulation pump in advance, and then adjusts the operation mode of the circulation pump by feedback of the sulfur dioxide amount monitored at the inlet and outlet of the desulfurization system.

[0015] In the present invention, by calculating the amount of sulfur dioxide in the flue gas entering the desulfurization system, the initial selection of the operating mode of the circulating pump can be close to the optimal operating mode of the circulating pump. Then, through the feedback of the monitored sulfur dioxide amount, the operating mode of the circulating pump can be adjusted to the optimal operating mode in the shortest time, thereby reasonably utilizing the operating combination of the circulating pump to achieve desulfurization energy saving.

[0016] The circulating pump coupling adjustment and control device realizes the automatic adjustment of the desulfurization circulating pump, greatly reducing the operating energy of the operating personnel and preventing system failures caused by operating errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of an ultra-low emission desulfurization energy-saving operation system based on full-process sulfur monitoring according to an embodiment of the present invention;

[0018] Figure 2 for Figure 1 The structural block diagram of the ultra-low emission desulfurization energy-saving operation system based on full-process sulfur monitoring.

[0019] In the figure, 1-coal quality detection device; 2-belt coal feeder; 3-pulverizer; 4-boiler; 5-desulfurization tower; 6-circulation pump; 7-export CEMS. DETAILED DESCRIPTION

[0020] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. Example

[0021] like Figure 1As shown, the ultra-low emission desulfurization energy-saving operation system based on the whole process monitoring of sulfur of the present invention is used in the desulfurization system of a coal-fired power plant, wherein the desulfurization system comprises a boiler 4, a belt coal feeder 2 and a coal mill 3 arranged in front of the boiler, a desulfurization tower 5 arranged behind the boiler 4, and a plurality of circulating pumps 6 arranged on the desulfurization tower 5; Figure 2 As shown, the desulfurization energy-saving operation system of the present invention includes a coal quality detection device, a circulation pump coupling adjustment and control device and a sulfur dioxide feedback device, the coal quality detection device includes a coal quality detector, a moisture meter and a parameter acquisition module, the circulation pump coupling adjustment and control device includes a calculation module, a circulation pump control module and a protection module, and the sulfur dioxide feedback device includes a desulfurization system outlet CEMS; the detector, moisture meter, parameter acquisition module and desulfurization system outlet CEMS are respectively connected to the calculation module, and the calculation module and the protection module are respectively connected to the circulation pump control module.

[0022] The coal quality detection device 1 is arranged on the belt coal feeder 2, wherein the coal quality detector and the moisture meter can directly measure the element value and moisture value of the coal entering the furnace respectively, and the parameter acquisition module can be connected to the belt coal feeder and the terminal operating system of the desulfurization system to collect the coal combustion amount of the coal entering the furnace and the operating parameters of the desulfurization system, and transmit all the measured values ​​to the calculation module of the circulating pump coupling adjustment and control device.

[0023] The calculation module receives the sulfur value, moisture value and coal consumption and calculates the sulfur dioxide content C that enters the real-time system according to the following formula: SO2 , and take the average value per minute and display it in the terminal system of the desulfurization system.

[0024] C SO2 =2×B×S,

[0025] C SO2 is the amount of sulfur dioxide entering the system, in kg;

[0026] B is the amount of coal consumed, in kg, measured by the belt coal feeder;

[0027] S is the sulfur content in the fuel, in %, measured by a coal quality detector.

[0028] The calculation module obtains the flue gas volume V entering the real-time desulfurization system according to the following formula, takes the average value per minute, and displays it in the terminal operating system of the desulfurization system.

[0029] V=0.01(1.867C+0.7S+0.8N+11.2H+1.24H 2 0)+0.79(0.2413Q / 1000+0.5)

[0030] V is the theoretical wet flue gas volume, in kg / m 3

[0031] C, S, N, H, H 2 0 are carbon, sulfur, nitrogen, hydrogen and water in coal, respectively, which are measured by coal quality detection device;

[0032] Q is the lower calorific value of coal, measured in kJ / kg by a coal quality testing device.

[0033] The calculation module compares the calculated sulfur dioxide and flue gas volumes entering the system with the sulfur dioxide and flue gas volumes in the original flue gas measured by the CEMS at the inlet of the desulfurization system, determines the change trend, and feeds the change trend back to the control module in the circulating pump coupling regulation and control device.

[0034] The circulating pump control module in the circulating pump coupling regulation and control device presets a large number of operating parameters (sulfur dioxide and flue gas volume, etc.) and corresponding circulating pump combination operation modes. The control module retrieves the optimal circulating pump operation combination mode recommended in the database under the operating conditions based on the sulfur dioxide and flue gas volume entering the system calculated by the calculation module, and other desulfurization operation parameters collected by the parameter acquisition module (such as the system's pH value, slurry density, limestone input, etc.), that is, selects the circulating pump combination operation mode corresponding to the parameter value closest to the sulfur dioxide and flue gas volume obtained by the calculation module, and uses it as the optimal circulating pump combination operation mode to control the start and stop of the circulating pump.

[0035] The calculation module in the circulating pump coupling regulation and control device calculates the sulfur dioxide value at the system outlet according to the optimal operating combination of the circulating pump selected by the circulating pump control module, and compares it with the set value (generally set at 35mg / Nm under ultra-low emission conditions). 3 The comparison result is transmitted to the control module, and the control module adjusts the operation mode of the circulation pump according to the comparison result, and then repeats the above calculation, comparison and adjustment operations until the sulfur dioxide value at the system outlet is less than the set value, and uses this as the operation mode to pre-adjust the circulation pump. This adjustment can be achieved automatically or by prompting the operator to perform manual operation.

[0036] The protection module in the circulating pump coupling regulation and control device sets the system operation protection value to ensure the safe operation of the entire desulfurization system. For example, under normal conditions, the system is set to ensure system safety, and at least two circulating pumps should be guaranteed to operate. Under this condition, no matter how low the sulfur dioxide value entering the system is calculated by the calculation module, at least two circulating pumps will be guaranteed to operate, that is, when the number of circulating pumps turned on in the optimal operating combination of the circulating pumps selected by the control module is less than two, the protection module can control the number of circulating pumps turned on to two through the circulating pump control module.

[0037] The protection module will also protect the operation safety of a single circulation pump and prevent the frequent start and stop of a single circulation pump. If a circulation pump needs to be started and stopped frequently under certain conditions, this solution will not be displayed as the best recommended solution.

[0038] The sulfur dioxide feedback device performs post-feedback judgment based on the sulfur dioxide content measured by the outlet CEMS of the outlet desulfurization system. The sulfur dioxide outlet is controlled within a more reasonable area (less than the set value). If the control value is too low, it means that the configuration margin for opening the circulation pump is large. If the outlet sulfur dioxide value is continuously higher than the set value during a period of time, it means that the circulation pump operation configuration is insufficient. The outlet CEMS of the desulfurization system monitors the outlet sulfur dioxide value of the desulfurization system and transmits it to the calculation module. The calculation module compares the monitored outlet sulfur dioxide value of the desulfurization system with the set value, and transmits the comparison result to the circulation pump control module. The circulation pump control module adjusts the circulation pump operation combination mode according to the comparison result; repeat the above comparison and adjustment operations until the outlet sulfur dioxide value is less than the set value. At this time, the circulation pump operation combination mode is the optimal circulation pump operation combination mode.

[0039] The present invention utilizes the above-mentioned rear feedback, the calculated value predicted by the front end, and the start-up configuration of the circulation pump to form a coupled correlation trend judgment. Example

[0040] The coal yard of a power plant prepares the coal for the furnace according to the calorific value and sulfur content. The coal enters the raw coal bunker through the belt coal feeder 2. The data measured by the coal quality detection device 1 is entered into the system. The calculation module in the circulation pump coupling regulation and control device calculates that the sulfur dioxide entering the system is 1200mg / Nm 3 , the flue gas volume is 125×10 4 m 3 / h. This data is directly entered into the circulation pump coupling regulation and control device.

[0041] The parameter acquisition module collects the operating pH value of the desulfurization system as 5.4, the slurry density in the desulfurization tower 5 is 1.021 g / ml, and the limestone slurry density is 1.195g / ml. There are 5 circulating pumps 6 in total, and the outlet sulfur dioxide value control index is 30mg / Nm 3 The current circulation pump operation mode is No. 1, No. 2, and No. 3 circulation pumps are running.

[0042] The above parameters are brought into the control module in the circulation pump coupling regulation and control system. Through big data comparison, the control module recommends the optimal operation scheme of circulating pump No. 1 and circulating pump No. 4. The outlet sulfur dioxide concentration is calculated to be 29 mg / Nm 3 At this time, the system prompts: Circulation pump No. 2 and circulation pump No. 3 will be shut down within 1 minute, and circulation pump No. 4 will be turned on at the same time.

[0043] The system is operated according to the above process, and the No. 1 and No. 4 circulation pumps are running. The outlet sulfur dioxide concentration is 28-30mg / Nm 3 , which is less than the set value, the sulfur dioxide feedback device determines that the circulation pump operation mode at this time is the optimal energy-saving mode, and records it into the big data system, which becomes one of the optional options for future operation adjustments.

[0044] The technical solutions of the present invention are not limited to the above-mentioned embodiments, and any technical solutions obtained by equivalent replacement methods fall within the scope of protection required by the present invention.

Claims

1. An ultra-low emission desulfurization energy-saving operation system based on full-process monitoring of sulfur, used in the desulfurization system of a coal-fired power plant, wherein the desulfurization system comprises a boiler, a coal feeder arranged in front of the boiler, a desulfurization tower arranged behind the boiler, and several circulating pumps arranged on the desulfurization tower, characterized in that: The desulfurization energy-saving operation system includes a coal quality detection device and a circulation pump coupling adjustment and control device. The coal quality detection device is arranged on the coal feeder. The circulation pump coupling adjustment and control device includes a computing module and a circulation pump control module connected to each other. The circulation pump control module is connected to the circulation pump. The coal quality detection device is connected to the computing module, and is used to detect the coal information of the coal entering the furnace, and transmit the coal information to the computing module; the computing module is used to calculate the operating parameters of the flue gas volume and sulfur dioxide volume entering the desulfurization system, and transmit the operating parameters to the circulation pump control module. The circulation pump control module pre-stores a variety of operating parameters and circulation pump operating combination modes corresponding to the operating parameters. The circulation pump control module obtains the optimal operating combination mode of the circulation pump by comparing the received operating parameters with the pre-stored operating parameters, and controls the start and stop of the circulation pump; The desulfurization system is provided with an outlet sulfur dioxide set value, and the calculation module is further used to calculate the outlet sulfur dioxide value of the desulfurization system according to the optimal operation combination mode of the circulation pump, and compare the calculated outlet sulfur dioxide value of the desulfurization system with the set value, and transmit the comparison result to the circulation pump control module, and the circulation pump control module adjusts the circulation pump operation combination mode according to the comparison result; repeat the above operation until the outlet sulfur dioxide value is equal to or less than the set value, and the circulation pump operation combination mode at this time is the optimal operation combination mode of the circulation pump; The desulfurization energy-saving operation system also includes a sulfur dioxide feedback device, which includes a desulfurization system outlet CEMS, which is used to monitor the desulfurization system outlet sulfur dioxide value and transmit it to the calculation module. The desulfurization system outlet sulfur dioxide value monitored by the calculation module is compared with the set value, and the comparison result is transmitted to the circulation pump control module. The circulation pump control module adjusts the circulation pump operation combination mode according to the comparison result; repeat the above operation until the deviation is minimized, and the circulation pump operation combination mode at this time is the optimal circulation pump operation combination mode; The coal quality detection device comprises a coal element detector and a moisture meter, and the coal element detector and the moisture meter are used to detect the sulfur content and moisture content of the coal fed into the furnace respectively.

2. The ultra-low emission desulfurization energy-saving operation system based on full-process sulfur monitoring according to claim 1 is characterized in that: The circulating pump coupling adjustment and control device also includes a protection module, which is connected to the circulating pump control module and is provided with a safe operation number of the circulating pump. When the number of circulating pumps turned on in the optimal operation combination mode of the circulating pump is less than the safe operation number, the protection module can control the number of circulating pumps turned on to be the safe operation number through the circulating pump control module.

3. The ultra-low emission desulfurization energy-saving operation system based on full-process monitoring of sulfur according to claim 1 is characterized in that: The coal quality detection device also includes a parameter acquisition module, which is used to collect the coal consumption of the desulfurization system and the operating parameters of the desulfurization system, and transmit the coal consumption and the operating parameters to the calculation module.

4. The ultra-low emission desulfurization energy-saving operation system based on full-process sulfur monitoring according to claim 3 is characterized in that: The desulfurization system parameters include the pH value of the system, slurry density and limestone input.

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