A desulfurization solution regeneration quality on-line monitoring system and on-line monitoring method

Abstract

The application discloses a kind of desulfurization solution regeneration quality on-line monitoring system and on-line monitoring method, and on-line monitoring system includes the desulfurization device and desulfurization solution regeneration device of intercommunication;Desulfurization device includes desulfurization tower;Desulfurization solution regeneration device includes regeneration tower, regeneration tower and desulfurization tower are communicated, reboiler is communicated at the bottom of regeneration tower, heating steam pipe is communicated on reboiler, and flowmeter and regulating valve are arranged on heating steam pipe;Desulfurization tower top is communicated with gravity separator, and hydrogen sulfide and total sulfur on-line analyzer are arranged on the outlet pipeline of gravity separator;Temperature measuring instrument is arranged on the top of regeneration tower;Hydrogen sulfide on-line analyzer, total sulfur on-line analyzer, temperature measuring instrument, flowmeter and regulating valve are signal connected with controller.The desulfurization solution regeneration quality on-line monitoring and judgment are realized, and the result is applied to the control of desulfurization solution regeneration heat source steam quantity, the desulfurization solution regeneration steam quantity is lowest under the premise of guaranteeing product natural gas quality, reaches the purpose of energy saving and consumption reduction, simultaneously also solves the desulfurization solution regeneration quality needing to be analyzed by manual sampling, and whether regeneration quality is qualified is judged according to experience.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of natural gas desulfurization and industrial tail gas desulfurization, and particularly relates to an online monitoring system and method for desulfurization solution regeneration quality. BACKGROUND

[0002] The desulfurization device is a commonly used treatment device for realizing natural gas desulfurization and industrial tail gas desulfurization, and is widely used in the petroleum, chemical, thermal power generation and other industries.

[0003] After the raw natural gas is desulfurized and dehydrated, it becomes product natural gas for external transmission. The desulfurization device removes hydrogen sulfide, organic sulfur and part of carbon dioxide in the raw gas natural gas, and is a key device for realizing the qualified external transmission of the product natural gas. In the desulfurization device, the desulfurization solution is recycled through processes such as flashing, filtering and regeneration, and therefore the quality of the solution regeneration is very important.

[0004] The solution containing hydrogen sulfide, organic sulfur and part of carbon dioxide is regenerated by resolving the absorbed hydrogen sulfide and other components under the conditions of high temperature and low pressure in the regeneration tower, and the heat source for the solution regeneration comes from the heating steam of the reboiler at the bottom of the regeneration tower. At present, the quality of the solution regeneration is mainly controlled by controlling the heating steam flow of the reboiler through the temperature at the top of the regeneration tower, so as to realize the control of the quality of the solution regeneration.

[0005] Firstly, since the temperature parameter at the top of the regeneration tower is greatly lagged, and it has no direct numerical value corresponding relationship and functional relationship with the quality of the solution regeneration, it is basically operated by experience; for the solution circulation of tens of tons to hundreds of tons per hour of the desulfurization device, the steam consumption is closely related to the control of the temperature at the top of the regeneration tower. In order to ensure the quality of the solution regeneration, the surplus of the temperature at the top of the regeneration tower is usually controlled to be very high, which leads to the over-high consumption of the steam of the reboiler, causing the waste of energy; at the same time, it also accelerates the deterioration of the solution, shortens the service life of the solution, and increases the evaporation amount of the water and the solution, thereby increasing the water consumption and the consumption of the solution of the device.

[0006] Secondly, the composition of the regenerated solution is artificially analyzed periodically, and then corresponding measures are taken according to the artificial analysis results to adjust the quality of the solution, such as supplementing the solution. The control of the quality of the solution regeneration of the existing desulfurization device relies on artificial sampling analysis, and the operating personnel adjust the desulfurization device according to the artificial analysis data, which has a serious lag in the operation adjustment and cannot meet the fine operation requirements of the desulfurization device with high product quality and high environmental protection requirements.

[0007] Finally, in the running process, there are frequent manual operation adjustment, operation adjustment lag, easy to cause disturbance to the desulfurization system, and the manual operation is not timely or improper operation will lead to product natural gas quality unqualified, heavy desulfurization device occurs pressure, interlock parking and other accidents, resulting in natural gas venting combustion, waste of energy. SUMMARY

[0008] The primary technical problem to be solved by the present application is that the existing natural gas desulfurization adopts the regeneration tower top temperature to control the steam addition amount, which has a lag, and the regeneration quality of the desulfurization solution is adjusted by manual sampling analysis, which also has a lag; the second is that the surplus amount of the regeneration tower top temperature is controlled too high, which leads to high steam consumption of the reboiler, increased water consumption and solution consumption, and shortened service life of the solution.

[0009] The first object of the present application provides a desulfurization solution regeneration quality online monitoring system, which comprises a desulfurization device and a desulfurization solution regeneration device in communication with each other;

[0010] The desulfurization device comprises a desulfurization tower; the desulfurization solution regeneration device comprises a regeneration tower, the regeneration tower and the desulfurization tower are in communication, the regeneration tower bottom is communicated with a reboiler, the reboiler is communicated with a heating steam pipe, and the heating steam pipe is provided with a flow meter and an adjusting valve;

[0011] The reboiler is provided with a steam coil, the semi-lean liquid is connected from the middle part of the regeneration tower to the bottom of the reboiler, the gas phase medium is connected from the pipeline at the top of the reboiler to the upper part of the regeneration tower tank, and the lean liquid is connected from the pipeline at the bottom of the reboiler to the lower part of the regeneration tower tank;

[0012] The desulfurization solution regeneration quality online monitoring system further comprises a controller; the desulfurization tower top is communicated with a gravity separator, the outlet pipeline of the gravity separator is provided with a hydrogen sulfide online analyzer and a total sulfur online analyzer; and the regeneration tower top is provided with a temperature measuring instrument;

[0013] The lean liquid inlet tower vertical pipeline of the desulfurization tower is provided with a differential pressure transmitter; the upper and lower pressure taking openings of the differential pressure transmitter are respectively arranged in the vertical direction on the lean liquid inlet tower vertical pipeline, and the distance between the sampling ports is not less than 2 times the measurement range of a single on-site liquid level meter installed on the tower tank;

[0014] The flow transmitter, differential pressure transmitter, hydrogen sulfide online analyzer, total sulfur online analyzer, temperature measuring instrument, flow meter and adjusting valve are all signal connected with the controller.

[0015] The present application adopts the differential pressure transmitter, the hydrogen sulfide on-line analyzer, the total sulfur on-line analyzer, the flow meter and the temperature measuring instrument, inputs the values measured by these instruments into the controller, and controls the opening degree of the regulating valve by the controller, so as to adjust the amount of the heating steam entering the reboiler more accurately and timely, avoid the waste of the heating steam, and save the energy consumption.

[0016] As a possible design, a system device with rich liquid flashing, rich liquid filtering, lean and rich liquid heat exchange and lean liquid cooling functions is arranged on the rich liquid and lean liquid pipeline communicated between the desulfurization tower and the regeneration tower, the rich liquid inlet end of the system device is communicated with the bottom of the desulfurization tower, the lean liquid inlet end of the system device is communicated with the bottom of the regeneration tower, the lean liquid outlet end of the system device is communicated with the top of the desulfurization tower, and the rich liquid outlet end of the system device is communicated with the top of the regeneration tower.

[0017] As a possible design, the controller comprises a temperature regulating proportional integral differential regulator, a differential pressure change rate regulating proportional integral differential regulator and a flow regulating proportional integral regulator.

[0018] The second object of the present application provides a desulfurization solution regeneration quality on-line monitoring method, which is realized based on the above-mentioned desulfurization solution regeneration quality on-line monitoring system.

[0019] When the hydrogen sulfide content in the purified gas at the top of the desulfurization tower is greater than or equal to a first set value or the total sulfur content is greater than or equal to a second set value, the controller controls the opening degree of the reboiler steam regulating valve by using the automatic control of the regeneration tower top temperature.

[0020] When the regeneration tower top temperature is greater than a set temperature, the opening degree of the regulating valve is reduced; when the regeneration tower top temperature is less than the set temperature, the opening degree of the regulating valve is increased.

[0021] In the above technical solution, the hydrogen sulfide content and the total sulfur content in the purified gas at the top of the desulfurization tower are used as the basis for controlling the opening degree of the regulating valve by using the regeneration tower top temperature, which avoids the general use of the regeneration tower top temperature to control the opening degree of the regulating valve in the prior art, overcomes the problem that there is no direct numerical and functional relationship between the regeneration tower top temperature and the regeneration quality, and basically solves the problem of manual sampling analysis in the prior art.

[0022] As a possible design, when the hydrogen sulfide content in the purified gas at the top of the desulfurization tower is less than the first set value and the total sulfur content is less than the second set value, the opening degree of the reboiler steam regulating valve is automatically controlled by using the following method:

[0023] The online monitoring system further comprises a differential pressure transmitter for measuring the pressure difference between the upper pressure tapping point and the lower pressure tapping point of the desulfurization tower.

[0024] According to the formula of ΔP=ρgΔh, the ΔP corresponding to the measuring range of the differential pressure transmitter is calculated 计 , wherein ρ is the theoretical density of the lean desulfurization solution from the regenerator at the working temperature of the desulfurization tower, kg / m 3 , g is the acceleration of gravity, and Δh is the distance between the upper pressure tapping point and the lower pressure tapping point of the differential pressure transmitter on the lean desulfurization solution inlet pipeline of the desulfurization tower.

[0025] According to the actual measured ΔP value of the differential pressure transmitter, the change rate ΔP% of ΔP is calculated according to the formula (I).

[0026] ΔP%=[ΔP-ΔP 计 ] / ΔP 计 ×100% (I)

[0027] When ΔP%> the set change rate value, the opening of the regulating valve is increased; and when ΔP%< the set change rate value, the opening of the regulating valve is decreased.

[0028] In the case of the above technical solution, the hydrogen sulfide content and the total sulfur content of the purified gas at the top of the desulfurization tower are taken as the basis for cutting off and starting the temperature control regulating valve of the top of the regenerator; when in the state of cutting off the temperature control of the top of the regenerator, the differential pressure change rate is taken as the basis for adjusting the opening of the regulating valve; when ΔP%> the set change rate value, the opening of the regulating valve is increased; and when ΔP%< the set change rate value, the opening of the regulating valve is decreased.

[0029] The beneficial effects of the present application are as follows:

[0030] 1. The online monitoring system and monitoring method for the regeneration quality of desulfurization solution disclosed in the present application realize online monitoring and judgment of the regeneration quality of desulfurization solution, propose specific judgment index values, and solve the problem that the regeneration quality of desulfurization solution needs to be analyzed by manual sampling and judged according to experience.

[0031] 2. The online monitoring system and monitoring method for the regeneration quality of desulfurization solution provide operation basis and time for the operation personnel to make fault prediction and early treatment on the regeneration quality of the solution of the desulfurization device, thereby reducing the number of shutdowns.

[0032] 3. The online monitoring and judgment results of the regeneration quality of desulfurization solution are applied to steam flow regulation, the minimum temperature at the top of the regenerator can be realized under the premise of ensuring the quality of natural gas products, thereby greatly reducing the steam consumption of the reboiler and achieving the purpose of energy saving. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor. In the drawings:

[0034] Figure 1 The schematic diagram of the online monitoring system for the regeneration quality of the desulfurization solution in the embodiment of the present application;

[0035] Figure 2 The logic control diagram of the heating steam regulating valve in the embodiment of the present application.

[0036] The marks in the drawings and the corresponding names of the parts:

[0037] 1-desulfurization tower, 2-differential pressure transmitter, 3-total sulfur online analyzer, 4-system device, 5-regeneration tower, 6-reboiler, 7-regulating valve, 8-gravity separator, 9-temperature measuring instrument, 10-hydrogen sulfide online analyzer, 11-flow transmitter, 12-flow meter. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present application more clear, the following will further describe the present application in combination with the embodiments and drawings, the illustrative embodiments of the present application and the description thereof are only used to explain the present application, and not as a limitation of the present application.

[0039] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0040] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more than two, unless otherwise specifically limited. The meaning of "several" is one or more than one, unless otherwise specifically limited.

[0041] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0042] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection, it can be mechanical connection, or electrical connection, it can be direct connection, or indirect connection through intermediate medium, it can be internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0043] The inventor of the present application found that in the existing natural gas desulfurization system, the amount of heating steam used for regenerating the desulfurization solution is adjusted according to the temperature of the top of the regeneration tower. When the temperature of the top of the regeneration tower increases (greater than the set value), the amount of heating steam is reduced, and when the temperature of the top of the regeneration tower decreases (less than the set value), the amount of heating steam is increased. It can be seen that the control condition of this control mode is single, and this control mode cannot ensure that the quality of the regenerated lean liquid in the regeneration tower is qualified (mainly the amount of hydrogen sulfide and total sulfur contained therein is enough to meet the standard), and manual on-site sampling and analysis are required to obtain various parameters of the lean liquid, and whether the set value of the temperature of the top of the regeneration tower and other parameters need to be adjusted is determined by the parameters. However, there is a certain lag in manual analysis, which cannot be used for timely determination of the control.

[0044] The inventor of the present application found that the content of hydrogen sulfide or total sulfur in the purified gas discharged from the top of the desulfurization tower is used as a criterion for whether to select to start using the temperature of the top of the regeneration tower to control the amount of heating steam, and when the temperature of the top of the regeneration tower is not used to control the amount of heating steam, the differential pressure change rate of the differential pressure transmitter provided on the lean liquid pipeline of the desulfurization tower is used to control the amount of heating steam. The above-mentioned control method of the amount of heating steam not only makes the amount of heating steam more scientific and reasonable, thereby reducing energy consumption, but also eliminates the need for manual analysis of whether the lean liquid generated after regeneration of the regeneration tower is qualified, has real-time control, is more accurate, and can save the cost of manual analysis.

[0045] As shown in Figure 1 The embodiment of the present application provides a desulfurization solution regeneration quality online monitoring system, which comprises a desulfurization device and a desulfurization solution regeneration device which are in communication with each other.

[0046] The desulfurization solution regeneration device comprises a desulfurization tower 1; the desulfurization solution regeneration device comprises a regeneration tower 5, the regeneration tower 5 and the desulfurization tower 1 are communicated, a reboiler 6 is communicated at the bottom of the regeneration tower 5, a heating steam pipe is communicated on the reboiler 6, and a flowmeter 12 and an adjusting valve 7 are arranged on the heating steam pipe;

[0047] The reboiler 6 is provided with a steam coil, the semi-lean liquid is connected from the middle of the regeneration tower 5 to the bottom of the reboiler 6, the gas phase medium is connected from the pipeline at the top of the reboiler 6 to the upper part of the tower kettle of the regeneration tower 5, and the lean liquid is connected from the pipeline at the bottom of the reboiler 6 to the lower part of the tower kettle of the regeneration tower 5;

[0048] The desulfurization solution regeneration quality on-line monitoring system further comprises a controller; the desulfurization tower 1 is communicated with a gravity separator 8 at the top, the outlet pipeline of the gravity separator 8 is provided with a hydrogen sulfide on-line analyzer and a total sulfur on-line analyzer; and the regeneration tower 5 is provided with a temperature measuring instrument 9 at the top.

[0049] The lean liquid inlet tower vertical pipeline of the desulfurization tower 1 is provided with a differential pressure transmitter 2; the upper and lower pressure taking openings of the differential pressure transmitter 2 are arranged in the vertical direction on the lean liquid inlet tower vertical pipeline respectively, and the distance between the sampling openings is not less than 2 times of the measurement range of a single on-site liquid level meter installed on the tower kettle of the desulfurization tower 1.

[0050] The flow transmitters 11, the differential pressure transmitter 2, the hydrogen sulfide on-line analyzer 10, the temperature measuring instrument 9, the total sulfur on-line analyzer 3, the flowmeter 12 and the adjusting valve 7 are all signal connected with the controller.

[0051] As shown in the figure, the values from the differential pressure transmitter 2, the hydrogen sulfide on-line analyzer 10, the total sulfur on-line analyzer 3, the flowmeter 12 and the temperature measuring instrument 9 are comprehensively processed by setting programs in the controller, so that the adjusting valve 7 is instructed to close or open, for accurately and timely adjusting the heating steam inlet amount, so as to save energy consumption while meeting the regeneration lean liquid quality requirements. Figure 1

[0052] Wherein, the controller can be a conventional controller in the art, for example: single-chip microcomputer, PLC, RTU, DCS, SIS and the like with program control function.

[0053] In actual application, in order to recover the heat of the lean liquid generated by the regeneration tower 5, a system device 4 is further arranged between the desulfurization tower 1 and the regeneration tower 5, wherein the system device 4 can comprise rich liquid flash evaporation, rich liquid filtration, lean and rich liquid heat exchange, lean liquid cooling and the like, for recovering the heat in the lean liquid and heating the rich liquid about to enter the regeneration tower 5, so as to realize the recycling of part of the heat, and the lean liquid after the system device enters the desulfurization tower 1 from the top of the desulfurization tower 1, so as to realize the utilization after regeneration. ​

[0054] In practical applications, the controller comprises a temperature-regulating proportional-integral-derivative regulator, a differential pressure rate-regulating proportional-integral-derivative regulator, and a flow-regulating proportional-integral regulator.

[0055] As shown in Figure 2 , Figure 2 PID1 is a temperature-regulating proportional-integral-derivative regulator, PID2 is a differential pressure rate-regulating proportional-integral-derivative regulator, and PID3 is a flow-regulating proportional-integral regulator.

[0056] Based on the above-mentioned online monitoring system for the regeneration quality of a desulfurization solution, as shown in Figure 2 , the present application further provides an online monitoring method for the regeneration quality of a desulfurization solution, which adopts automatic control of the opening degree of a reboiler steam regulating valve by using the regeneration tower overhead temperature when the hydrogen sulfide content in the overhead purified gas of the desulfurization tower is greater than or equal to a first set value or the total sulfur content is greater than or equal to a second set value.

[0057] When the regeneration tower overhead temperature is greater than a set temperature, the opening degree of the regulating valve is reduced; and when the regeneration tower overhead temperature is less than the set temperature, the opening degree of the reboiler steam regulating valve is increased.

[0058] In the present embodiment, the regulating valve 7 is used to regulate the amount of heating steam entering the reboiler 6, and the greater the opening degree of the reboiler steam regulating valve 7, the greater the amount of heating steam entering the reboiler 6, and vice versa.

[0059] In the present embodiment, the first set value and the second set value can be adjusted according to different quality index values of the purified gas, the upper limit of the value range should be lower than the maximum value of the quality index value, and the lower limit of the value range should be higher than two-thirds of the maximum value of the quality index value. The set rate value can be adjusted according to the different performances of different desulfurization solutions.

[0060] For example, if the gas to be purified is natural gas, then the first set value and the second set value need to be set according to the requirements for the content of each component in the purified gas obtained after purification of natural gas. For example, the mass indexes of hydrogen sulfide and total sulfur of a class of natural gas are respectively ≤6 mg / m 3 and ≤20 mg / m 3 , as specified in “Natural Gas” (GB 17820-2018).

[0061] The first set value and the second set value are generally smaller than the specified values in the corresponding standards. For example, when the raw material gas is natural gas, the value range of the first set value is generally 4-5.5 mg / m 3 , more suitably 4-5 mg / m 3 , and most suitably 5 mg / m 3The second set value typically ranges from 15 to 19.5 mg / m³. 3 A more suitable concentration is 15–18 mg / m². 3 The most suitable concentration is 16 mg / m². 3 .

[0062] In this embodiment, when the hydrogen sulfide content in the purified gas at the top of the desulfurization tower 1 is ≥ the first set value or the total sulfur content is ≥ the second set value, the opening program of the reboiler steam regulating valve 7 at the top of the regeneration tower 5 is started, that is, PID1 and PID3 work, while PID2 does not work.

[0063] When the temperature at the top of regeneration tower 5 rises (above the set value), the opening of the reboiler steam regulating valve 7 decreases; conversely, the opening of the reboiler steam regulating valve 7 decreases and increases. Under this regulation, the quality of the regenerated lean liquor obtained is qualified, requiring no manual sampling and analysis, and there is no lag. Furthermore, this quality does not need to be used as the basis for adding desulfurization solution.

[0064] It should be noted that the aforementioned raw gas includes not only natural gas, but also other gases that require desulfurization, such as industrial exhaust gas.

[0065] like Figure 2 As shown, in this embodiment, when the hydrogen sulfide content in the purified gas at the top of the desulfurization tower 1 is less than the first set value and the total sulfur content is less than the second set value, according to the above, the temperature at the top of the regeneration tower 5 cannot be used to control the opening of the regulating valve. Therefore, under the condition that the regenerated lean liquid is qualified and the purified gas is qualified, PID2 and PID3 work, and PID1 does not work, as detailed below.

[0066] Calculate the ΔP corresponding to the measurement range of differential pressure transmitter 2 based on ΔP = ρgΔh. 计 The value ρ represents the density of the lean desulfurization solution from regeneration tower 5 at the operating temperature before entering desulfurization tower 1, in kg / m³. 3 g is the acceleration due to gravity, and Δh is the distance between the upper and lower pressure taps of the differential pressure transmitter on the lean liquid inlet pipeline of the desulfurization tower.

[0067] The ΔP value obtained by the differential pressure transmitter 2 is calculated according to ΔP = ρgΔh, and the rate of change of ΔP% is calculated according to formula (I).

[0068] ΔP%=[ΔP-ΔP 计 ] / ΔP 计 ×100%(I)

[0069] When ΔP% > the set rate of change, the opening of the control valve increases; when ΔP% < the set rate of change, the opening of the control valve decreases.

[0070] It should be noted that: solution regeneration is a process of desorbing hydrogen sulfide, carbon dioxide, organic sulfur and other substances absorbed by the desulfurization solution under high temperature and low pressure. The effect of regeneration is different, the content of hydrogen sulfide and other substances contained in the solution is different, so as to cause the change of solution density, thereby causing the change of differential pressure. The measured value ΔP is the full liquid level between the upper and lower pressure taps during work, h is constant, and the effect of solution regeneration is different, which will cause the change of solution density, thereby causing the change of ΔP.

[0071] In actual application, according to the different physicochemical properties of different desulfurization solutions, the ΔP% change rate can be adjusted accordingly to meet the actual needs. Since the content of hydrogen sulfide and other substances in the solution after regeneration is low, in order to expand the influence of different regeneration effects on the change of solution density, the pressure tap range of the differential pressure transmitter can be expanded. The desulfurization tower is from tens of meters to several tens of meters high, and the vertical pipeline of the tower is also from tens of meters to several tens of meters long.

[0072] By using the differential pressure change rate of the differential pressure transmitter 2 as the basis for adjusting the opening of the reboiler steam regulating valve 7, not only qualified purified gas can be obtained, but also manual sampling and analysis of the quality of the regenerated lean liquid produced by the regeneration tower are not required, and the quality is not used as the basis for adding desulfurization solution. There is no hysteresis, which is beneficial to timely supplement of new desulfurization solution.

[0073] Theoretically, the ΔP% of the solution after regeneration is zero. In actual application, the better the regeneration effect, the smaller the ΔP%; the worse the regeneration effect, the larger the ΔP%. Since the ΔP% cannot fluctuate around 0, a target value needs to be set as the basis for the reboiler steam regulating valve 7 to adjust.

[0074] For raw gas being natural gas, the value range of the target value is generally 1.8% to 3%, more appropriately 1.8% to 2%, and most appropriately 2%.

[0075] In actual application, the control of the regulating valve 7 depends on the content of each component in the purified gas. According to different raw gas, the content of each component in the purified gas will be different, and the selection can be made according to the actual situation.

[0076] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An on-line monitoring system for the quality of regeneration of a desulfurization solution, characterized in that, The desulfurization device and the desulfurization solution regeneration device are connected with each other; The desulfurization device comprises a desulfurization tower, and the desulfurization solution regeneration device comprises a regeneration tower, wherein the regeneration tower and the desulfurization tower are connected, the bottom of the regeneration tower is connected with a reboiler, the reboiler is connected with a heating steam pipe, and the heating steam pipe is provided with a flow meter and an adjusting valve; The reboiler is provided with a steam coil, the semi-lean liquid is connected to the bottom of the reboiler from the middle of the regeneration tower, the gas-phase medium is connected to the upper part of the regeneration tower tower kettle from the pipeline at the top of the reboiler, and the lean liquid is connected to the lower part of the regeneration tower tower kettle from the pipeline at the bottom of the reboiler; The desulfurization solution regeneration quality online monitoring system further comprises a controller, the top of the desulfurization tower is connected with a gravity separator, the outlet pipeline of the gravity separator is provided with a hydrogen sulfide online analyzer and a total sulfur online analyzer, and the top of the regeneration tower is provided with a temperature measuring instrument; The lean liquid inlet tower vertical pipeline of the desulfurization tower is provided with a differential pressure transmitter, the upper and lower pressure taking openings of the differential pressure transmitter are arranged on the lean liquid inlet tower vertical pipeline in the vertical direction, and the distance between the sampling openings is not less than 2 times of the measurement range of a single on-site liquid level meter installed on the tower kettle of the desulfurization tower; The desulfurization tower is provided with a flow transmitter, and the flow transmitter, the differential pressure transmitter, the hydrogen sulfide online analyzer, the total sulfur online analyzer, the temperature measuring instrument, the flow meter and the adjusting valve are signal connected with the controller.

2. The on-line monitoring system for regeneration quality of desulfurization solution according to claim 1, characterized in that, The rich liquid and lean liquid pipelines connected between the desulfurization tower and the regeneration tower are provided with a system device with rich liquid flashing, rich liquid filtering, lean and rich liquid heat exchange and lean liquid cooling functions, the rich liquid inlet end of the system device is connected with the bottom of the desulfurization tower, the lean liquid inlet end of the system device is connected with the bottom of the regeneration tower, the lean liquid outlet end of the system device is connected with the top of the desulfurization tower, and the rich liquid outlet end of the system device is connected with the top of the regeneration tower.

3. The on-line monitoring system for regeneration quality of desulfurization solution according to claim 1, characterized in that, The controller comprises a temperature adjusting proportional integral differential regulator, a differential pressure change rate adjusting proportional integral differential regulator and a flow adjusting proportional integral regulator.

4. An on-line monitoring method of the quality of regeneration of a desulfurization solution, characterized in that, The desulfurization solution regeneration quality online monitoring system is realized based on the desulfurization solution regeneration quality online monitoring system of claim 1 or 2; When the hydrogen sulfide content in the purified gas out of the desulfurization tower is greater than or equal to a first set value or the total sulfur content is greater than or equal to a second set value, the opening degree of the reboiler steam adjusting valve is automatically controlled by the regeneration tower top temperature; When the regeneration tower top temperature is greater than a set temperature, the opening degree of the adjusting valve is reduced, and when the regeneration tower top temperature is less than the set temperature, the opening degree of the adjusting valve is increased.

5. The method according to claim 4, wherein the method is characterized by, When the hydrogen sulfide content in the purified gas out of the desulfurization tower is less than the first set value and the total sulfur content is less than the second set value, the opening degree of the reboiler steam adjusting valve is automatically controlled in the following manner: According to ΔP = ρgΔh, the ΔP corresponding to the measurement range of the differential pressure transmitter is calculated 计 The value of ρ is the theoretical density of the lean desulfurization solution from the regeneration tower at the working temperature before entering the desulfurization tower, in kg / m 3 g is the acceleration of gravity, and Δh is the distance between the upper pressure tapping port and the lower pressure tapping port of the differential pressure transmitter on the lean desulfurization solution inlet pipeline. According to the ΔP value actually measured by the differential pressure transmitter, the change rate ΔP% of ΔP is calculated according to formula (I); ΔP% = [ΔP - ΔP 计 ] / ΔP 计 × 100% (I) When ΔP% is greater than a set change rate value, the opening degree of the adjusting valve is increased, and when ΔP% is less than the set change rate value, the opening degree of the adjusting valve is reduced.

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