Desulfurization system and control method thereof

Abstract

The invention discloses a desulfurization system and a control method thereof. The control method of the desulfurization system comprises the following steps: when the concentration of hydrogen sulfide in gas discharged from a gas output end of a desulfurization tower is always greater than a first concentration threshold value within a first set duration, controlling the opening degree of a barren liquor control valve to be increased to a first preset opening degree so as to increase the flow of barren liquor flowing into the desulfurization tower; and controlling the desulfurization system to operate for a second set time under the condition that the opening degree of the barren liquor control valve is kept at the first preset opening degree. Desulfurized gas such as coal gas is desulfurized through desulfurization liquid in a desulfurization tower, the concentration of hydrogen sulfide in gas discharged from the desulfurization tower is detected in real time, and when the concentration of hydrogen sulfide exceeds the standard, the opening degree of a barren liquor control valve is controlled to be increased, so that the flow of barren liquor flowing into the desulfurization tower from a regeneration tower is increased, and the desulfurization strength in the desulfurization tower is improved; the problem that gas discharged by the desulfurizing tower is unqualified is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of desulfurization, and in particular to a desulfurization system and a control method thereof. Background Art

[0002] Cyanides such as hydrogen sulfide and hydrogen cyanide contained in coke oven gas are harmful substances that can corrode chemical product recovery equipment and gas transmission pipelines and storage facilities. In addition, the gases generated by the combustion of hydrogen sulfide and hydrogen cyanide pollute the air, so hydrogen sulfide and hydrogen cyanide must be removed during the coke oven gas purification process.

[0003] However, in the prior art, the sulfur content in the coal gas after desulfurization may still be relatively high, the desulfurization is unqualified, and effective desulfurization cannot be achieved. Summary of the invention

[0004] The present invention provides a desulfurization system and a control method thereof. When the sulfur content of the desulfurized gas output from the desulfurization tower exceeds the standard, the desulfurization intensity is increased to solve the problem of unqualified gas discharged from the desulfurization tower.

[0005] According to one aspect of the present invention, a control method for a desulfurization system is provided, wherein the desulfurization system comprises: a desulfurization tower, a regeneration tower and a lean liquid control valve; the desulfurization tower comprises a first reaction section, wherein a desulfurized liquid and a desulfurized gas react in the first reaction section and generate a rich liquid after the reaction; the lean liquid control valve is arranged on a pipeline between a first output end of the regeneration tower and a first input end of the first reaction section; the first output end of the first reaction section is connected to a first input end of the regeneration tower so as to input the rich liquid into the regeneration tower, and the regeneration tower is used to heat the rich liquid to reduce the hydrogen content in the rich liquid and generate a lean liquid output;

[0006] The control method of the desulfurization system comprises:

[0007] When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is greater than the first concentration threshold value for a first set time period, controlling the opening of the lean liquid control valve to increase to a first preset opening to increase the flow rate of the lean liquid flowing into the desulfurization tower;

[0008] The desulfurization system is controlled to operate the lean liquid control valve at the first preset opening for a second set time period.

[0009] Optionally, the desulfurization system further includes a reboiler and a steam control valve, the reboiler includes a first pipeline and a second pipeline that are independent of each other, the input end of the first pipeline is connected to the second output end of the regeneration tower, the output end of the first pipeline is connected to the second input end of the regeneration tower, the input end of the second pipeline is connected to the steam control valve, and the output end of the second pipeline is connected to a steam generating device; the first pipeline is used to circulate the lean liquid output from the regeneration tower, and the second pipeline is used to circulate steam;

[0010] After controlling the desulfurization system to maintain the opening of the lean liquid control valve at the first preset opening for a second set time, the method further includes:

[0011] Obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower;

[0012] When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is always greater than the first concentration threshold value within the first set time period, controlling the opening of the steam control valve to increase to a second preset opening to increase the flow rate of steam for heat exchange with the lean liquid in the regeneration tower;

[0013] The desulfurization system is controlled to operate for a third set time period so that the opening of the steam control valve remains at the second preset opening.

[0014] Optionally, after controlling the desulfurization system to operate the lean liquid control valve at the first preset opening for a second set time and obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower, the method further includes:

[0015] When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is less than or equal to the first concentration threshold value within the first set time period, the lean liquid control valve is controlled to decrease from the first preset opening to the first default preset opening.

[0016] Optionally, after controlling the desulfurization system to maintain the opening of the steam control valve at the second preset opening for a third set time, the method further includes:

[0017] Obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower;

[0018] When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is less than or equal to the first concentration threshold value within the first set time period, the opening of the steam control valve is controlled to be reduced from the second preset opening to the second default preset opening, and the opening of the lean liquid control valve is controlled to be reduced from the first preset opening to the first default preset opening.

[0019] Optionally, the desulfurization tower further includes a second reaction section, which is arranged above the first reaction section, and the desulfurization system further includes an alkali washing circulation tank and an alkali circulation volume control valve, which is arranged on a pipeline between an output end of the alkali washing circulation tank and an input end of the second reaction section, and the alkali washing circulation tank is used to input alkali washing liquid into the second reaction section;

[0020] After controlling the desulfurization system to operate the steam control valve at the second preset opening for a third set time, and obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower, the method further includes:

[0021] When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is always greater than the first concentration threshold value within the first set time period, controlling the opening of the alkali circulation amount control valve to increase to a third preset opening, so as to increase the flow rate of the alkali washing solution input into the second reaction section;

[0022] The desulfurization system is controlled to operate for a fourth set time period at an opening of the alkali circulation amount control valve being the third preset opening.

[0023] Optionally, the desulfurization system further includes an alkali supplement tank and an alkali supplement control valve; the alkali supplement control valve is arranged on a pipeline between an output end of the alkali supplement tank and an input end of the alkali washing circulation tank, and the alkali supplement tank is used to input alkaline substances into the alkali washing circulation tank to increase the density of the alkali washing liquid in the alkali washing circulation tank;

[0024] After controlling the desulfurization system to operate the alkali circulation control valve at the third preset opening for a fourth set time, the method further includes:

[0025] Obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower;

[0026] When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is always greater than the first concentration threshold value within the first set time period, the opening of the alkali replenishment control valve is controlled to increase to a fourth preset opening to increase the density of the alkali washing solution input into the second reaction section;

[0027] The desulfurization system is controlled to operate for a fifth set time period at a fourth preset opening so that the opening of the alkali replenishment control valve remains the fourth preset opening.

[0028] Optionally, after controlling the desulfurization system to operate for a fourth set time at the opening of the alkali circulation control valve at the third preset opening and obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower, the method further includes:

[0029] When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is less than or equal to the first concentration threshold value within the first set time period, the opening of the alkali circulation volume control valve is controlled to be reduced from the third preset opening to the third default preset opening, the opening of the steam control valve is controlled to be reduced from the second preset opening to the second default preset opening, and the opening of the lean liquid control valve is controlled to be reduced from the first preset opening to the first default preset opening.

[0030] Optionally, after controlling the desulfurization system to maintain the opening of the alkali replenishment control valve at the fourth preset opening for a fifth set time, the method further includes:

[0031] Obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower;

[0032] When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is less than or equal to the first concentration threshold value within the first set time period, the opening of the alkali replenishment control valve is controlled to be reduced from the fourth preset opening to the fourth default preset opening, the opening of the alkali circulation volume control valve is controlled to be reduced from the third preset opening to the third default preset opening, the opening of the steam control valve is controlled to be reduced from the second preset opening to the second default preset opening, and the opening of the lean liquid control valve is controlled to be reduced from the first preset opening to the first default preset opening.

[0033] Optionally, the desulfurization system further includes a rich liquid tank, a third pipeline, a fourth pipeline, a rich liquid density monitor, a soft water replenishing valve, and a potassium hydroxide replenishing valve; the first output end of the desulfurization tower is connected to the input end of the rich liquid tank, the rich liquid density monitor is arranged on the pipeline between the output end of the rich liquid tank and the first input end of the regeneration tower, the soft water replenishing valve is arranged on the third pipeline to control the flow rate of water input into the rich liquid tank, and the potassium hydroxide replenishing valve is arranged on the fourth pipeline to control the flow rate of potassium hydroxide input into the rich liquid tank;

[0034] The control method of the desulfurization system also includes:

[0035] obtaining the density of the rich liquid input into the regeneration tower by means of the rich liquid density monitor;

[0036] When the density of the rich liquid is greater than the preset density of the rich liquid, controlling the opening of the soft water replenishing valve to increase, and / or controlling the opening of the potassium hydroxide replenishing valve to decrease;

[0037] When the density of the rich liquid is less than the preset density of the rich liquid, the opening of the soft water replenishing valve is controlled to decrease, and / or the opening of the potassium hydroxide replenishing valve is controlled to increase.

[0038] According to another aspect of the present invention, a desulfurization system is provided, comprising: a desulfurization tower, a regeneration tower, a lean liquid control valve and a controller; the desulfurization tower comprises a first reaction section, a desulfurization liquid and a desulfurized gas react in the first reaction section, and a rich liquid is generated after the reaction; the lean liquid control valve is arranged on a pipeline between a first output end of the regeneration tower and a first input end of the first reaction section; the first output end of the first reaction section is connected to a first input end of the regeneration tower, so as to input the rich liquid into the regeneration tower; the regeneration tower is used to heat the rich liquid to reduce the hydrogen content in the rich liquid, and generate a lean liquid output;

[0039] The controller is connected to the lean liquid control valve, and is used to control the opening of the lean liquid control valve to increase to a first preset opening when the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is always greater than a first concentration threshold within a first set time period, so as to increase the flow rate of the lean liquid flowing into the desulfurization tower;

[0040] The controller is also used to control the desulfurization system to operate the lean liquid control valve at the first preset opening for a second set time period.

[0041] The technical solution of the embodiment of the present invention is to desulfurize the desulfurized gas such as coal gas in the desulfurization tower by means of desulfurization liquid, and detect the concentration of hydrogen sulfide in the gas discharged from the desulfurization tower in real time. When the concentration of hydrogen sulfide exceeds the standard, the opening of the lean liquid control valve is controlled to increase, thereby increasing the flow rate of lean liquid flowing from the regeneration tower to the desulfurization tower, increasing the desulfurization intensity in the desulfurization tower, and solving the problem of unqualified gas discharged from the desulfurization tower.

[0042] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0044] Figure 1 A schematic diagram of the structure of a desulfurization system provided by an embodiment of the present invention;

[0045] Figure 2 A flow chart of a control method for a desulfurization system provided by an embodiment of the present invention;

[0046] Figure 3 A flow chart of another desulfurization system control method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0047] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0048] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0049] Figure 1 A schematic diagram of the structure of a desulfurization system provided in an embodiment of the present invention is shown in FIG. Figure 2 A flow chart of a control method for a desulfurization system provided by an embodiment of the present invention, referring to Figure 1 and Figure 2Optionally, the desulfurization system includes: a desulfurization tower 1, a regeneration tower 2, and a lean liquid control valve 3; the desulfurization tower 1 includes a first reaction section 101, the desulfurization liquid and the desulfurized gas react in the first reaction section 101, and generate a rich liquid after the reaction; the lean liquid control valve 3 is arranged on the pipeline between the first output end U2 of the regeneration tower 2 and the first input end I2 of the first reaction section 101; the first output end U1 of the first reaction section 101 is connected to the first input end I1 of the regeneration tower 2 to input the rich liquid into the regeneration tower 2, and the regeneration tower 2 is used to heat the rich liquid to reduce the hydrogen content in the rich liquid and generate a lean liquid output. Among them, the desulfurization liquid can be a sodium bicarbonate solution, and the desulfurized gas can be coal gas. The sodium bicarbonate solution and the coal gas react in the first reaction section 101 so that the sodium bicarbonate solution absorbs the acid gas and hydrogen sulfide in the coal gas to reduce the content of hydrogen sulfide in the coal gas, and the liquid after the reaction is called rich liquid, which is output to the first input end I1 of the regeneration tower 2 through the first output end U1 of the first reaction section 101. The rich liquid input into the regeneration tower 2 is heated to reach the boiling point, and the hydrogen ions in the rich liquid are analyzed, and the hydrogen ions are converted into steam and discharged through the gas output end U3 of the regeneration tower 2 to reduce the hydrogen content in the rich liquid, and the rich liquid after the reaction in the regeneration tower 2 is called lean liquid. The lean liquid is circulated again into the desulfurization tower 1 through the pipeline connected between the first output end U2 of the regeneration tower 2 and the first input end I2 of the first reaction section 101 of the desulfurization tower 1 to react with the desulfurized gas. The lean liquid control valve 3 can be an electronic valve, and the opening size of the valve is used to control the size of the lean liquid flow rate flowing into the first reaction section 101. Optionally, the desulfurization system also includes a lean liquid pump 5, a heat exchanger 6, a cooler 7, a lean liquid flow monitor 8 and a lean liquid density analyzer 9, which are sequentially arranged between the first output end U2 of the regeneration tower 2 and the lean liquid control valve 3. The heat exchanger 6 includes two independent pipelines, one independent pipeline is used to transport the rich liquid output from the desulfurization tower 1 to the regeneration tower 2, and the other is used to transport the lean liquid output from the regeneration tower 2 to the desulfurization tower 1. The lean liquid flow monitor 8 is used to monitor the flow of the lean liquid output by the cooler 7. The lean liquid control valve 3 and the lean liquid flow monitor 8 form a first logic control. The size of the lean liquid flow obtained by the lean liquid flow monitor 8 and the size of the expected lean liquid flow are used to control and adjust the opening size of the lean liquid control valve 3.

[0050] The control method of the desulfurization system includes:

[0051] S110: When the concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1 is greater than the first concentration threshold within a first set time period, the opening of the lean liquid control valve 3 is controlled to increase to a first preset opening to increase the flow rate of lean liquid flowing into the desulfurization tower 1.

[0052] The first concentration threshold is the minimum value of the concentration when judging that the concentration of hydrogen sulfide exceeds the standard, which can be set according to user needs, such as 300 mg / m. The first set time is the shortest time when the concentration of hydrogen sulfide is always greater than the first concentration threshold when judging that the concentration of hydrogen sulfide exceeds the standard, such as 15 minutes. Both the first concentration threshold and the first set time can be set according to user needs without specific limitation.

[0053] Optionally, a hydrogen sulfide online monitor may be provided on the inner wall of the first reaction section 101 to obtain the gas output end U4 of the desulfurization tower 1, or the desulfurization system further includes a hydrogen sulfide online monitor 4, which is provided at the gas output end U4 of the desulfurization tower 1 and is used to detect in real time the concentration of hydrogen sulfide in the gas output from the desulfurization tower 1. The concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1 is obtained by the hydrogen sulfide online monitor 4. When the concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1 is greater than the first concentration threshold value for a first set time period, it is determined that the hydrogen sulfide content exceeds the standard, and the opening of the lean liquid control valve 3 is controlled to increase to the first preset opening, thereby increasing the flow rate of the lean liquid input into the first reaction section 101 of the desulfurization tower 1, such as from the normal lean liquid flow rate of 115m / s to the lean liquid flow rate of 115m / s. 3 / h increased to 115-130m 3 / h operation to increase the desulfurization strength in the desulfurization tower 1. The first preset opening is set according to user needs, such as 80% of the total opening of the lean liquid control valve 3.

[0054] S120: Control the desulfurization system to operate the lean liquid control valve 3 at a first preset opening for a second set time period.

[0055] The opening of the lean liquid control valve 3 is controlled to increase to a first preset opening. When the opening of the lean liquid control valve is maintained at the first preset opening, the desulfurization system is controlled to run for a second set time, such as 20 minutes, 30 minutes or 60 minutes. It can be set according to user needs, so that the desulfurization system increases the desulfurization intensity of the coal gas after increasing the content of lean liquid that reacts with the coal gas in the desulfurization tower 1, so as to reduce the content of hydrogen sulfide in the gas output from the desulfurization tower 1.

[0056] The technical solution of the embodiment of the present invention is to desulfurize the desulfurized gas such as coal gas in the desulfurization tower by means of desulfurization liquid, and detect the concentration of hydrogen sulfide in the gas discharged from the desulfurization tower in real time. When the concentration of hydrogen sulfide exceeds the standard, the opening of the lean liquid control valve is controlled to increase, thereby increasing the flow rate of lean liquid flowing from the regeneration tower to the desulfurization tower, increasing the desulfurization intensity in the desulfurization tower, and solving the problem of unqualified gas discharged from the desulfurization tower.

[0057] Figure 3 A flow chart of another control method of a desulfurization system provided by an embodiment of the present invention, referring to Figure 2 and Figure 3On the basis of the above embodiment, the desulfurization system further includes a reboiler 10 and a steam control valve 11. The reboiler 10 includes a first pipeline and a second pipeline that are independent of each other. The input end of the first pipeline is connected to the second output end U5 of the regeneration tower 2, the output end of the first pipeline is connected to the second input end I3 of the regeneration tower 2, the input end of the second pipeline is connected to the steam control valve 11, and the output end of the second pipeline is connected to the steam generating device to circulate the steam; the first pipeline is used to circulate the lean liquid output from the regeneration tower 2, and the second pipeline is used to circulate the steam. The steam control valve 11 can be an electronic valve, and the opening of the valve is used to control the flow rate of the steam input to the regeneration tower 2. The reboiler 10 can be understood as a heat exchanger, and the lean liquid output from the regeneration tower 2 and the steam are heat exchanged in the reboiler 10 to heat the lean liquid in the regeneration tower 2. Optionally, the desulfurization system also includes a steam flow monitor 12, which is arranged at the front end of the steam control valve 11 to obtain the flow rate of the steam input to the reboiler 10. The steam control valve 11 and the steam flow monitor 12 form a second logic control, and the opening size of the steam control valve 11 is controlled according to the steam flow obtained by the steam flow monitor 12 and the size of the expected steam flow. Optionally, the desulfurization system also includes: a rich liquid tank 13, a third pipeline, a fourth pipeline, a rich liquid density monitor 14, a soft water supplement valve 15, and a potassium hydroxide supplement valve 16; the first output end U1 of the desulfurization tower 1 is connected to the input end of the rich liquid tank 13 through the first rich liquid pump 17, the rich liquid density monitor 14 is arranged on the output end of the rich liquid tank 13 and the first input end I1 of the regeneration tower 1, specifically on the pipeline between the heat exchanger 6, the soft water supplement valve 15 is arranged on the third pipeline, and is used to control the flow of water input into the rich liquid tank 13, and the potassium hydroxide supplement valve 16 is arranged on the fourth pipeline, and is used to control the flow of potassium hydroxide input into the rich liquid tank 13. A first rich liquid control valve 18 is also provided on the pipeline between the first rich liquid pump 17 and the input end of the rich liquid tank 13, which is used to control the flow rate of the rich liquid input into the rich liquid tank 13 through the desulfurization tower 1. The liquid level of the desulfurization tower 1 and the first rich liquid control valve 18 form a third logic control, which is used to stabilize the liquid holding capacity in the desulfurization tower 1; the rich liquid is sent to the rich liquid tank 13 through the first rich liquid pump 17, and enters the regeneration tower 2 through the second rich liquid pump 19 through the regeneration rich liquid valve 20 provided between the heat exchanger 6 and the input end I2 of the regeneration tower 2 for cyclic analysis and regeneration desulfurization. The soft water replenishment valve 15 is used for water replenishment operation control, and the soft water flow monitor 21 provided on the third pipeline and located at the front end of the soft water replenishment valve 15 is used to monitor the soft water replenishment flow; the soft water replenishment valve 15 and the soft water flow monitor 21 form a fourth logic control, and the opening size of the soft water replenishment valve 15 is controlled and adjusted according to the size relationship between the actual flow obtained by the soft water flow monitor 21 and the expected soft water flow.The potassium hydroxide replenishing valve 16 is used to control the remote replenishment of the circulating desulfurization liquid, that is, the rich liquid. The potassium hydroxide flow monitor 22 arranged on the fourth pipeline and located at the front end of the potassium hydroxide replenishing valve 16 is used to monitor the potassium hydroxide replenishing flow. The potassium hydroxide flow monitor 22 and the rich liquid density monitor 14 form the fifth logic control, and the potassium hydroxide flow monitor 22 and the potassium hydroxide replenishing valve 16 form the sixth logic control. When the rich liquid density is lower than or higher than the set value, the sixth logic control is triggered by the feedback signal of the fifth logic control to increase or decrease the rich liquid density. The soft water replenishing valve 15 and the potassium hydroxide replenishing valve 16 are mainly used for the consumption and replacement replenishment of the rich liquid in the rich liquid tank 13, and to ensure the density and quality of the rich liquid.

[0058] Optionally, the density of the rich liquid input into the regeneration tower 2 is obtained by the rich liquid density monitor 14; when the density of the rich liquid is greater than the preset density of the rich liquid, the opening of the soft water replenishing valve 15 is controlled to increase, and / or the opening of the potassium hydroxide replenishing valve 16 is controlled to decrease; when the density of the rich liquid is less than the preset density of the rich liquid, the opening of the soft water replenishing valve 15 is controlled to decrease, and / or the opening of the potassium hydroxide replenishing valve 16 is controlled to increase. By adjusting the opening sizes of the soft water replenishing valve 15 and the potassium hydroxide replenishing valve 16, the density of the rich liquid input from the rich liquid tank 13 into the regeneration tower 2 is adjusted. Specifically, the opening of the soft water replenishing valve 15 is controlled to decrease, and the opening of the potassium hydroxide replenishing valve 16 is controlled to increase to increase the density of the rich liquid input into the regeneration tower 2, and the opening of the soft water replenishing valve 15 is controlled to increase, and the opening of the potassium hydroxide replenishing valve 16 is controlled to decrease to reduce the density of the rich liquid input into the regeneration tower 2.

[0059] Optionally, the desulfurization tower 1 further includes a second reaction section 102, which is arranged above the first reaction section 101, and the desulfurization system further includes an alkali washing circulation tank 23 and an alkali circulation amount control valve 24, the alkali circulation amount control valve 24 is arranged between the output end U6 of the alkali washing circulation tank 23 and the input end I4 of the second reaction section 102, and the alkali washing circulation tank 23 is used to input an alkali washing liquid into the second reaction section 102. The alkali washing liquid is an alkaline solution containing sodium hydroxide, which is used to further react with the desulfurized gas in the second reaction section 102 to absorb hydrogen sulfide in the coal gas. An alkali washing liquid flow monitor 25 is also arranged in sequence on the pipeline between the alkali circulation amount control valve 24 and the input end I3 of the second reaction section 102, which is used to monitor the flow of the alkali washing liquid input into the second reaction section 102, and an alkali washing liquid density monitor 26 is used to monitor the density of the alkali washing liquid input into the second reaction section 102. The alkali washing circulation tank 23 is used for storing the alkali washing liquid of the second reaction section 102. The alkali circulation amount control valve 24 and the alkali washing liquid flow monitor 25 form a seventh logic control for controlling the alkali washing liquid flow. The desulfurization system also includes an alkali washing liquid reflux control valve 27 disposed between the alkali washing circulation tank 23 and the output end U7 of the second reaction section 102. The alkali washing liquid reflux control valve 27 and the liquid level of the second reaction section 102 form an eighth logic control, and the opening size of the alkali washing liquid reflux control valve 27 is controlled by the set liquid level of the second reaction section 102.

[0060] Optionally, the desulfurization system further includes an alkali supplement tank 28 and an alkali supplement control valve 29; the alkali supplement control valve 29 is arranged on the pipeline between the output end of the alkali supplement tank 28 and the input end of the alkali washing circulation tank 23, and the alkali supplement tank 28 is used to input alkaline substances, i.e., sodium hydroxide, into the alkali washing circulation tank 23 through the alkali supplement pump 30 and the alkali supplement control valve 29 to increase the density of the alkali washing liquid in the alkali washing circulation tank 23. Optionally, an alkaline substance flow monitor 31 is also arranged between the alkali supplement control valve 29 and the input end of the alkali washing circulation tank 23, which is used to monitor the flow of the alkaline substance input into the alkali washing circulation tank 23. The alkali supplement control valve 29 and the alkaline substance flow monitor 31 form an eighth logic control, and the opening size of the alkali supplement control valve 29 is automatically controlled by the size relationship between the actual alkaline substance flow detected and the expected alkaline substance flow. The alkaline substance flow monitor 31 and the alkaline washing liquid density monitor 26 form a ninth logic control, and control the opening of the alkali replenishment control valve 29 according to the relationship between the actual density of the alkaline washing liquid detected by the alkaline washing liquid density monitor 26 and the expected density of the alkaline washing liquid.

[0061] In addition, the desulfurization system further includes a wastewater replenishment control valve 32 and a wastewater flow monitor 33 disposed between the wastewater replenishment control valve 32 and the alkali washing circulation tank 23. The wastewater replenishment control valve 32 is used to input pure water into the alkali washing circulation tank 23. The wastewater replenishment control valve 32 and the wastewater flow monitor 33 form a tenth logic control, and the wastewater flow monitor 33 and the liquid level of the alkali washing circulation tank 23 form an eleventh logic control. The opening of the wastewater replenishment control valve 32 is automatically controlled according to the given liquid level of the alkali washing circulation tank 23 to control the amount of replenishment water, and the feedback signal of the eleventh logic control affects the tenth logic control.

[0062] The control methods of the desulfurization system include:

[0063] S111: When the concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1 is greater than the first concentration threshold within a first set time period, the opening of the lean liquid control valve 3 is controlled to increase to a first preset opening to increase the flow rate of lean liquid flowing into the desulfurization tower 1.

[0064] S121: Control the desulfurization system to operate the lean liquid control valve 3 at a first preset opening for a second set time period.

[0065] S131: Obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower 1.

[0066] After controlling the desulfurization system to operate at the first preset opening of the lean liquid control valve 3 for a second set time period, a hydrogen sulfide online monitor 4 can be set on the inner wall of the first reaction stage 101 to obtain the concentration of hydrogen sulfide in the gas output from the first reaction stage, or the concentration of hydrogen sulfide in the gas output from the first reaction stage can be obtained by using a hydrogen sulfide online monitor 4 set at the gas output end of the desulfurization tower 1.

[0067] The execution of S141 or S151 is determined according to the relationship between the concentration of hydrogen sulfide in the gas discharged from the gas output terminal U4 of the desulfurization tower 1 within the first set time period and the first concentration threshold.

[0068] S141: When the concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1 is less than or equal to the first concentration threshold value within a first set time period, the lean liquid control valve 3 is controlled to decrease from the first preset opening to the first default preset opening.

[0069] After the opening of the lean liquid control valve 3 is increased to the first preset opening and runs for the second set time, the coal gas in the desulfurization tower 1 is further desulfurized, and the content of hydrogen sulfide in the discharged gas is qualified, the opening of the lean liquid control valve 3 is restored to the first default preset opening set by the desulfurization system, such as 50% of the total opening of the lean liquid control valve 3, to control the normal desulfurization of the desulfurization system.

[0070] S151: When the concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1 is greater than the first concentration threshold within a first set time period, the opening of the steam control valve 11 is controlled to increase to a second preset opening to increase the flow rate of steam for heat exchange with the lean liquid in the regeneration tower.

[0071] After the opening of the lean liquid control valve 3 is increased to the first preset opening and the second set time is run, after the coal gas in the desulfurization tower 1 is further desulfurized, when the hydrogen sulfide content in the discharged gas still exceeds the standard, the desulfurization strength needs to be further increased. The opening of the steam control valve 11 is controlled to increase to the second preset opening, such as 70% of the total opening of the steam control valve 11, so as to increase the heat input to the regeneration tower 2, such as gradually increasing the steam flow rate from 3t / h to 5t / h during normal operation, so that the decomposition strength of hydrogen in the regeneration tower 2 is increased, thereby reducing the hydrogen content in the lean liquid input from the regeneration tower 2 to the desulfurization tower 1, which is more conducive to the reaction between the lean liquid and the coal gas. Therefore, after steps S111 and S121, when the desulfurization of the desulfurization tower does not meet the standard, the reaction quality of the lean liquid and the coal gas in the desulfurization tower 1 is improved by increasing the flow rate of steam for heat exchange with the lean liquid in the regeneration tower 2, so as to increase the desulfurization strength. The second preset opening can be set according to user needs and is not specifically limited here.

[0072] S161: Control the desulfurization system to operate the steam control valve 11 at a second preset opening for a third set time period.

[0073] The opening of the steam control valve 11 is controlled to increase to a second preset opening. When the opening of the steam control valve 11 is maintained at the second preset opening, the desulfurization system is controlled to run for a third set time, such as 20 minutes, 30 minutes or 60 minutes. The time can be set according to user needs, so that the desulfurization system increases the desulfurization intensity of the coal gas after improving the quality of the lean liquid that reacts with the coal gas in the desulfurization tower 1, so as to reduce the content of hydrogen sulfide in the gas output from the desulfurization tower 1.

[0074] S171: Obtain the concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1.

[0075] The concentration of hydrogen sulfide in the gas discharged from the gas output terminal U4 of the desulfurization tower 1 is obtained by the hydrogen sulfide online monitor 4. S181 or 191 is executed according to the magnitude relationship between the concentration of hydrogen sulfide and the first concentration threshold within the first set time period.

[0076] S181: When the concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1 is less than or equal to the first concentration threshold value within the first set time period, the opening of the steam control valve 11 is controlled to be reduced from the second preset opening to the second default preset opening, and the opening of the lean liquid control valve 3 is controlled to be reduced from the first preset opening to the first default preset opening.

[0077] After controlling the opening of the steam control valve 11 to increase, and the content of hydrogen sulfide in the desulfurization tower 1 meets the desulfurization standard, the opening of the steam control valve 11 is gradually controlled to be restored to the second default preset opening, such as 30% of the total opening of the steam control valve 11, and the opening of the lean liquid control valve 3 is controlled to be restored to the first default preset opening, so that the desulfurization system works in normal desulfurization mode.

[0078] S191: When the concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1 is greater than the first concentration threshold within the first set time period, the opening of the alkali circulation control valve 24 is controlled to increase to a third preset opening to increase the flow rate of the alkali washing solution input into the second reaction section 102.

[0079] After increasing the opening of the lean liquid control valve 3 and the steam control valve 11 and running them for a certain period of time, the concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1 is obtained again. If at this time, the concentration of hydrogen sulfide is always greater than the first concentration threshold value within the first set time, the desulfurization treatment by the first reaction stage 101 alone cannot effectively reduce the hydrogen sulfide content in the coal gas, and the desulfurization intensity needs to be further enhanced with the help of the second reaction stage 102. Control the opening of the alkali circulation control valve 24 to increase to a third preset opening, such as 70% of the total opening of the alkali circulation control valve 24, so as to increase the flow rate of the alkali washing liquid input to the second reaction stage 102, such as from 50m 3 / h up to 70m 3 / h to further increase the desulfurization intensity in the desulfurization tower 1.

[0080] S201: Controlling the desulfurization system to operate for a fourth set time period when the opening of the alkali circulation control valve 24 is at a third preset opening.

[0081] The fourth set time can be set according to user needs, such as 20 minutes, 30 minutes or 60 minutes. When the opening of the alkali circulation control valve 24 is maintained at the third preset opening, the desulfurization system is controlled to operate for the fourth set time, so that the desulfurization system increases the desulfurization strength of the coal gas in the desulfurization tower 1 through a two-stage reaction, in order to reduce the content of hydrogen sulfide in the gas output from the desulfurization tower 1.

[0082] S211: Obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1.

[0083] The execution of S221 or S231 is determined based on the relationship between the concentration of hydrogen sulfide in the gas discharged from the gas output terminal U4 of the desulfurization tower 1 and the first concentration threshold value.

[0084] S221: When the concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1 is less than or equal to the first concentration threshold value within the first set time period, the opening of the alkali circulation volume control valve 24 is controlled to be reduced from the third preset opening to the third default preset opening, the opening of the steam control valve 11 is controlled to be reduced from the second preset opening to the second default preset opening, and the opening of the lean liquid control valve 3 is controlled to be reduced from the first preset opening to the first default preset opening.

[0085] After the desulfurization tower operates for a fourth set time at the third preset opening of the alkali circulation control valve 24, if the content of hydrogen sulfide in the gas output by the desulfurization tower 1 meets the standard, the alkali circulation control valve 24, the steam control valve 11 and the lean liquid control valve 3 are sequentially controlled to restore to their corresponding default preset openings, so that the desulfurization system operates in normal mode. In normal mode, each valve in the desulfurization system is maintained at a preset default value.

[0086] S231: When the concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1 is greater than the first concentration threshold within the first set time period, the opening of the alkali replenishment control valve 29 is controlled to increase to a fourth preset opening to increase the density of the alkali washing solution input into the second reaction section 102.

[0087] After controlling the opening of the alkali circulation volume control valve 24 to increase to the third preset opening, controlling the opening of the steam control valve 11 to increase to the second preset opening, and controlling the opening of the lean liquid control valve 3 to increase to the first preset opening, when the hydrogen sulfide content in the gas output from the desulfurization tower 1 still exceeds the standard, the opening of the alkali replenishment control valve 29 is controlled to increase to the fourth preset opening, such as 60% of the total opening of the alkali replenishment control valve 29, so as to increase the content of sodium hydroxide input into the alkali washing circulation tank 23, and then increase the density of the alkali washing solution input into the second reaction section 102, so as to further increase the desulfurization intensity.

[0088] S241: Control the desulfurization system to operate the alkali replenishment control valve 29 at a fourth preset opening for a fifth set time period.

[0089] The fifth set time can be set according to user needs, such as 30 minutes or more. When the opening of the alkali replenishment control valve 29 is maintained at the fourth preset opening, the desulfurization system is controlled to operate for the fifth set time, so that the desulfurization system increases the desulfurization strength of the coal gas in the desulfurization tower 1 through a two-stage reaction, in order to reduce the content of hydrogen sulfide in the gas output from the desulfurization tower 1. Among them, the second set time, the third set time, the fourth set time and the fifth set time can all be equal.

[0090] S251: Obtain the concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1.

[0091] S261: When the concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1 is less than or equal to the first concentration threshold value within the first set time period, the opening of the alkali replenishment control valve 29 is controlled to be reduced from the fourth preset opening to the fourth default preset opening, the opening of the alkali circulation volume control valve 24 is controlled to be reduced from the third preset opening to the third default preset opening, the opening of the steam control valve 11 is controlled to be reduced from the second preset opening to the second default preset opening, and the opening of the lean liquid control valve 3 is controlled to be reduced from the first preset opening to the first default preset opening.

[0092] After the desulfurization tower runs for the fifth set time at the fourth preset opening of the alkali replenishment control valve 29, if the content of hydrogen sulfide in the gas output by the desulfurization tower 1 meets the standard, the alkali replenishment control valve 29, the alkali circulation control valve 24, the steam control valve 11 and the lean liquid control valve 3 are controlled in turn to restore to their respective corresponding default preset openings, so that the desulfurization system operates in normal mode.

[0093] The present invention also provides a desulfurization system, referring to Figure 1 , including a desulfurization tower 1, a regeneration tower 2, a lean liquid control valve 3 and a controller, the desulfurization tower 1 includes a first reaction section 101, the desulfurization liquid and the desulfurized gas react in the first reaction section 101, and generate a rich liquid after the reaction; the lean liquid control valve 3 is arranged on a pipeline between a first output end U2 of the regeneration tower 2 and a first input end I2 of the first reaction section 101; the first output end U1 of the first reaction section 101 is connected to the first input end I1 of the regeneration tower 2 to input the rich liquid into the regeneration tower 2; the regeneration tower 2 is used to heat the rich liquid to reduce the hydrogen content in the rich liquid and generate a lean liquid output.

[0094] The controller is connected to the lean liquid control valve 3. The controller is used to control the opening of the lean liquid control valve 3 to increase to a first preset opening when the concentration of hydrogen sulfide in the gas discharged from the gas output end U4 of the desulfurization tower 1 is greater than the first concentration threshold value within a first set time period, so as to increase the flow rate of the lean liquid flowing into the desulfurization tower 1;

[0095] The controller is also used to control the desulfurization system to operate for a second set time period at a first preset opening of the lean liquid control valve 3 .

[0096] The controller can execute the control method of the desulfurization system in each of the above-mentioned embodiments, which will not be described in detail here. The technical solution of the embodiment of the present invention is to desulfurize the desulfurized gas such as coal gas in the desulfurization tower by using the desulfurization liquid, and detect the concentration of hydrogen sulfide in the gas discharged from the desulfurization tower in real time. When the concentration of hydrogen sulfide exceeds the standard, the controller controls the opening of the lean liquid control valve to increase, thereby increasing the flow of the desulfurization liquid flowing from the regeneration tower to the desulfurization tower, increasing the desulfurization intensity in the desulfurization tower, and solving the problem of unqualified gas discharged from the desulfurization tower. And the entire control process can be automatically adjusted in real time through real-time monitoring, and the level of intelligent operation is high.

[0097] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0098] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A control method for a desulfurization system, characterized in that: The desulfurization system comprises: a desulfurization tower, a regeneration tower and a lean liquid control valve; the desulfurization tower comprises a first reaction section, a desulfurization liquid and a desulfurized gas react in the first reaction section, and a rich liquid is generated after the reaction; the lean liquid control valve is arranged on a pipeline between a first output end of the regeneration tower and a first input end of the first reaction section; the first output end of the first reaction section is connected to a first input end of the regeneration tower so as to input the rich liquid into the regeneration tower, and the regeneration tower is used to heat the rich liquid to reduce the hydrogen content in the rich liquid and generate a lean liquid output; The control method of the desulfurization system comprises: When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is greater than the first concentration threshold value for a first set time period, controlling the opening of the lean liquid control valve to increase to a first preset opening to increase the flow rate of the lean liquid flowing into the desulfurization tower; The desulfurization system is controlled to operate the lean liquid control valve at the first preset opening for a second set time period.

2. The control method of the desulfurization system according to claim 1, characterized in that: The desulfurization system further includes a reboiler and a steam control valve, the reboiler includes a first pipeline and a second pipeline that are independent of each other, the input end of the first pipeline is connected to the second output end of the regeneration tower, the output end of the first pipeline is connected to the second input end of the regeneration tower, the input end of the second pipeline is connected to the steam control valve, and the output end of the second pipeline is connected to the steam generating device; The first pipeline is used for circulating the lean liquid output from the regeneration tower, and the second pipeline is used for circulating steam; After controlling the desulfurization system to maintain the opening of the lean liquid control valve at the first preset opening for a second set time, the method further includes: Obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower; When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is always greater than the first concentration threshold value within the first set time period, controlling the opening of the steam control valve to increase to a second preset opening to increase the flow rate of steam for heat exchange with the lean liquid in the regeneration tower; The desulfurization system is controlled to operate for a third set time period so that the opening of the steam control valve remains at the second preset opening.

3. The control method of the desulfurization system according to claim 2, characterized in that: After controlling the desulfurization system to maintain the opening of the lean liquid control valve at the first preset opening for a second set time, and obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower, the method further includes: When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is less than or equal to the first concentration threshold value within the first set time period, the lean liquid control valve is controlled to decrease from the first preset opening to the first default preset opening.

4. The control method of the desulfurization system according to claim 2, characterized in that: After controlling the desulfurization system to maintain the opening of the steam control valve at the second preset opening for a third set time, the method further includes: Obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower; When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is less than or equal to the first concentration threshold value within the first set time period, the opening of the steam control valve is controlled to be reduced from the second preset opening to the second default preset opening, and the opening of the lean liquid control valve is controlled to be reduced from the first preset opening to the first default preset opening.

5. The control method of the desulfurization system according to claim 4, characterized in that: The desulfurization tower further includes a second reaction section, which is arranged above the first reaction section. The desulfurization system further includes an alkali washing circulation tank and an alkali circulation volume control valve, which is arranged on a pipeline between an output end of the alkali washing circulation tank and an input end of the second reaction section. The alkali washing circulation tank is used to input alkali washing liquid into the second reaction section. After controlling the desulfurization system to operate the steam control valve at the second preset opening for a third set time, and obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower, the method further includes: When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is always greater than the first concentration threshold value within the first set time period, controlling the opening of the alkali circulation amount control valve to increase to a third preset opening, so as to increase the flow rate of the alkali washing solution input into the second reaction section; The desulfurization system is controlled to operate for a fourth set time period at an opening of the alkali circulation amount control valve being the third preset opening.

6. The control method of the desulfurization system according to claim 5, characterized in that: The desulfurization system further includes an alkali supplement tank and an alkali supplement control valve; the alkali supplement control valve is arranged on a pipeline between an output end of the alkali supplement tank and an input end of the alkali washing circulation tank, and the alkali supplement tank is used to input alkaline substances into the alkali washing circulation tank to increase the density of the alkali washing liquid in the alkali washing circulation tank; After controlling the desulfurization system to operate the alkali circulation control valve at the third preset opening for a fourth set time, the method further includes: Obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower; When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is always greater than the first concentration threshold value within the first set time period, the opening of the alkali replenishment control valve is controlled to increase to a fourth preset opening to increase the density of the alkali washing solution input into the second reaction section; The desulfurization system is controlled to operate for a fifth set time period at a fourth preset opening so that the opening of the alkali replenishment control valve remains the fourth preset opening.

7. The control method of the desulfurization system according to claim 6, characterized in that: After controlling the desulfurization system to operate for a fourth set time at the opening of the alkali circulation control valve at the third preset opening, and obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower, the method further includes: When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is less than or equal to the first concentration threshold value within the first set time period, the opening of the alkali circulation volume control valve is controlled to be reduced from the third preset opening to the third default preset opening, the opening of the steam control valve is controlled to be reduced from the second preset opening to the second default preset opening, and the opening of the lean liquid control valve is controlled to be reduced from the first preset opening to the first default preset opening.

8. The control method of the desulfurization system according to claim 6, characterized in that: After controlling the desulfurization system to maintain the opening of the alkali replenishment control valve at the fourth preset opening for a fifth set time, the method further includes: Obtaining the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower; When the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is less than or equal to the first concentration threshold value within the first set time period, the opening of the alkali replenishment control valve is controlled to be reduced from the fourth preset opening to the fourth default preset opening, the opening of the alkali circulation volume control valve is controlled to be reduced from the third preset opening to the third default preset opening, the opening of the steam control valve is controlled to be reduced from the second preset opening to the second default preset opening, and the opening of the lean liquid control valve is controlled to be reduced from the first preset opening to the first default preset opening.

9. The control method of the desulfurization system according to claim 1, characterized in that: The desulfurization system further includes a rich liquid tank, a third pipeline, a fourth pipeline, a rich liquid density monitor, a soft water replenishing valve, and a potassium hydroxide replenishing valve; the first output end of the desulfurization tower is connected to the input end of the rich liquid tank, the rich liquid density monitor is arranged on the pipeline between the output end of the rich liquid tank and the first input end of the regeneration tower, the soft water replenishing valve is arranged on the third pipeline, and is used to control the flow rate of water input into the rich liquid tank, and the potassium hydroxide replenishing valve is arranged on the fourth pipeline, and is used to control the flow rate of potassium hydroxide input into the rich liquid tank; The control method of the desulfurization system also includes: obtaining the density of the rich liquid input into the regeneration tower by means of the rich liquid density monitor; When the density of the rich liquid is greater than the preset density of the rich liquid, controlling the opening of the soft water replenishing valve to increase, and / or controlling the opening of the potassium hydroxide replenishing valve to decrease; When the density of the rich liquid is less than the preset density of the rich liquid, the opening of the soft water replenishing valve is controlled to decrease, and / or the opening of the potassium hydroxide replenishing valve is controlled to increase.

10. A desulfurization system, characterized in that: include: A desulfurization tower, a regeneration tower, a lean liquid control valve and a controller; the desulfurization tower includes a first reaction section, in which a desulfurized liquid and a desulfurized gas react to generate a rich liquid after the reaction; the lean liquid control valve is arranged on a pipeline between a first output end of the regeneration tower and a first input end of the first reaction section; the first output end of the first reaction section is connected to a first input end of the regeneration tower to input the rich liquid into the regeneration tower; the regeneration tower is used to heat the rich liquid to reduce the hydrogen content in the rich liquid and generate a lean liquid output; The controller is connected to the lean liquid control valve, and is used to control the opening of the lean liquid control valve to increase to a first preset opening when the concentration of hydrogen sulfide in the gas discharged from the gas output end of the desulfurization tower is always greater than a first concentration threshold within a first set time period, so as to increase the flow rate of the lean liquid flowing into the desulfurization tower; The controller is also used to control the desulfurization system to operate the lean liquid control valve at the first preset opening for a second set time period.

Images