Cooperative processing method and system for online quality evaluation and purification of organic amine liquid

Abstract

The invention relates to the technical field of organic amine liquid treatment, and discloses a cooperative treatment method and system for online quality evaluation and purification of organic amine liquid, and the system comprises an early warning unit, a filtering unit and a desalting unit. The treatment method comprises the following steps: step 1, online evaluation of organic amine liquid: the organic amine liquid enters an early warning unit, and a conductivity meter and a turbidity meter perform online evaluation on the quality of the organic amine liquid; step 2, mode selection: 1, when the turbidity detection value of the early warning unit exceeds a set early warning value and the conductivity detection value is lower than the set early warning value, only a filtering mode is started; 2, when the carbon capture system performs intermittent organic amine liquid purification treatment, a high-salt-low-salt mode is adopted; and 3, when the carbon capture system performs continuous organic amine liquid purification treatment, a low-salt mode is adopted. The problems of low desalination efficiency, large loss of organic amine, large amount of purified wastewater, high alkali consumption and the like in the organic amine purification treatment process in the prior art are solved.

Description

Technical Field

[0001] The invention relates to the technical field of organic amine liquid treatment, and in particular to a collaborative treatment method and system for online quality assessment and purification of organic amine liquid. Background Art

[0002] In response to the national "carbon peak and carbon neutrality" mission goals, high-carbon emission industries such as thermal power, petrochemicals, steel, and cement have carried out carbon capture work. Among them, chemical absorption is the most mature and commercially valuable carbon capture technology. However, under high-temperature aerobic environment and multi-substance contact conditions, the organic amine liquid used in chemical absorption carbon capture projects is prone to thermal degradation, oxidative degradation, and chemical degradation. Degradation forms heat-stable salts (HSS) such as formate, acetate, oxalate, and thiosulfate. Long-term enrichment in the carbon capture system has many adverse effects, including: (1) Heat-stable salts will bind organic amine absorbents, reduce the effective concentration of organic amine liquid in the system, and affect the capture efficiency of the system; (2) Heat-stable salt enrichment will cause corrosion to system equipment, pipelines, and tanks; (3) Heat-stable salts and corrosion particle products will increase the foaming tendency of the solution, which will seriously endanger the safe operation of the system. Therefore, in order to maintain the long-term efficient and stable operation of the carbon capture system, effective measures must be taken to maintain the quality of the organic amine liquid.

[0003] At present, organic amine liquid purification can be used to reduce the content of heat-stable salts, improve the quality and absorption capacity of organic amine liquid, and eliminate adverse effects. Organic amine liquid purification technologies include vacuum distillation technology, ion exchange resin technology, and ion exchange membrane technology.

[0004] The vacuum distillation technology uses the boiling point difference of different substances in the organic amine liquid to separate the materials. Under negative pressure conditions, the temperature is controlled to separate the organic amine liquid from the thermally stable salt, thereby achieving the purpose of desalination. This technology was used to a certain extent in the early days, but due to the disadvantages of high energy consumption, large organic amine loss, and low desalination efficiency, it has been gradually replaced by other purification technologies.

[0005] Ion exchange resin technology uses the principle of selective adsorption of anions in organic amine liquid by resin to remove heat-stable salts. This technology has the advantages of low desalination energy consumption, low organic amine loss and thorough desalination, and is currently the mainstream organic amine liquid purification treatment technology. However, this technology cannot remove cations in organic amine liquid, and has disadvantages such as large wastewater discharge and high alkali consumption. In the context of increasingly stringent environmental protection requirements, related problems are particularly prominent.

[0006] Ion exchange membrane technology uses permselective membranes to remove anions and cations. An external electric field is used to direct the movement of anions and cations in the organic amine solution, and the anions and cations are separated from the organic amine solution according to the permselective properties of the ion exchange membrane, thereby achieving the purpose of removing thermally stable salts. The disadvantages of this technology are that the ion exchange membrane is easily contaminated and the replacement cost is high. At the same time, there is a problem of serious reduction in desalination capacity under low-salinity conditions. Therefore, it is imperative to seek an optimized solution for the purification of organic amine solutions. Summary of the invention

[0007] The present invention aims to provide a collaborative treatment method and system for online quality assessment and purification of organic amine liquid, so as to solve the problems of low desalination effect, large organic amine loss, large amount of purified wastewater and high alkali consumption in the organic amine purification process in the prior art.

[0008] To achieve the above object, the present invention adopts the following technical scheme: a coordinated treatment system for online quality assessment and purification of organic amine liquid, including an early warning unit, a filtration unit, and a desalination unit, wherein the desalination unit includes an ion exchange membrane desalination module and an ion exchange resin desalination module.

[0009] Preferably, as an improvement, the early warning unit includes a conductivity meter and a turbidity meter.

[0010] Preferably, as an improvement, the filter unit comprises two-stage filter modules, and the two-stage filter modules are arranged in series.

[0011] Preferably, as an improvement, the filtering type of the two-stage filtering module is at least one of bag filtering, pleated filter element filtering, and activated carbon filtering.

[0012] Preferably, as an improvement, the filtering accuracy of the primary filtering module and the secondary filtering module is set in a gradient, the filtering accuracy of the primary filtering module is 10 μm, 5 μm or 1 μm, and the filtering accuracy of the secondary filtering module is 1 μm or 0.5 μm.

[0013] Preferably, as an improvement, a collaborative treatment method for online quality assessment and purification of an organic amine solution comprises the following steps:

[0014] Step 1: Online evaluation of organic amine liquid: The organic amine liquid enters the early warning unit, and the conductivity meter and turbidity meter conduct online evaluation of the quality of the organic amine liquid;

[0015] Step 2: Mode selection:

[0016] 1. When the turbidity detection value of the warning unit exceeds the set warning value, and the conductivity detection value is lower than the set warning value, only the filtering mode is started;

[0017] 2. When the carbon capture system performs intermittent organic amine liquid purification treatment, the high-salt-low-salt mode is adopted; the conductivity detection value of the early warning unit is set with a high-salt value, a low-salt value and an operating value, and the purification system is efficiently regulated by the conductivity change; when the conductivity detection value of the early warning unit exceeds the high-salt value, the high-salt-low-salt mode is started; when the conductivity detection value of the early warning unit is close to the low-salt value, the purification system switches from the high-salt mode to the low-salt mode;

[0018] 3. When the carbon capture system is undergoing continuous organic amine liquid purification treatment, the low-salt mode is adopted; when the conductivity detection value of the early warning unit is lower than the operating value, the system is shut down.

[0019] Preferably, as an improvement, the threshold values ​​of the conductivity meter of the warning unit are set as follows: high salt value 5ms / cm, low salt value 3ms / cm, and operating value 1.5ms / cm.

[0020] Preferably, as an improvement, the thresholds of the turbidity meter of the early warning unit are set as follows: early warning value 4000NTU, operating value 500NTU.

[0021] Preferably, as an improvement, the method further comprises step three, collecting the purified carbon capture organic amine liquid to detect the thermal stability salt content and suspended matter content.

[0022] The principle and advantages of this scheme are: in view of the weak online quality assessment method of carbon capture organic amine liquid and the disadvantages of low desalination effect, large organic amine loss, large amount of purified wastewater, and high alkali consumption in purification technology, this technical scheme proposes a coordinated treatment method and system for online quality assessment and purification of organic amine liquid, and collects a large amount of test data through on-site sampling and analysis by using the early warning unit (conductivity meter and turbidity meter), and accurately and effectively corresponds the conductivity with the thermally stable salt content of the solution, turbidity and suspended matter content, etc., and successfully realizes that the quality of organic amine liquid can be quantitatively judged by conductivity and turbidity, and the online quality assessment of carbon capture organic amine liquid is completed. The purification mode is regulated and directed by using the results of thermally stable salt content and suspended matter content detection, and the advantages of ion exchange membrane rapid desalination in high-salt areas and ion exchange resin thorough desalination in low-salt areas are fully utilized and combined to maximize the desalination efficiency and reduce the loss of organic amine. During the desalination treatment of organic amine liquid in low-salt mode, the purified waste liquid generated by the ion exchange resin module is deeply treated by the ion exchange membrane desalination module to achieve a waste liquid concentration reduction of more than 50%.

[0023] The beneficial effects of this technical solution are:

[0024] 1. The early warning unit of this technical solution is equipped with a conductivity meter and a turbidity meter, which can accurately and real-time detect and complete the online quality assessment of the carbon capture organic amine liquid, filling the gap in the online quality assessment of organic amine liquid in industrial applications; at the same time, it can also provide instructions for the rapid start and stop and precise regulation of the back-end organic amine liquid purification system.

[0025] 2. The filtering unit of this technical solution is provided with two-stage series filtering modules, and the stepped interception accuracy configuration of the two-stage filtering modules is utilized to ensure efficient interception of suspended matter of different particle sizes, improve the removal rate of suspended matter, and avoid clogging of the filter element.

[0026] 3. This technical solution is equipped with two sets of desalination modules, namely, ion exchange membrane and ion exchange resin, which can meet the desalination and purification requirements of the carbon capture system during operation to the greatest extent, and realize the fully automatic switching between low-salt mode and high-salt-low-salt mode. The ion exchange membrane module has the characteristics of fast desalination and small amount of waste liquid under high-salt conditions, but poor desalination capacity and large organic amine loss under low-salt conditions; while the ion exchange resin has strong desalination capacity, small organic amine loss and thorough desalination under low-salt conditions, but there are problems of large amount of desalination wastewater and high alkali consumption. This patent combines the advantages of the two technologies and avoids the disadvantages. It uses ion exchange membrane modules in high-salt areas and ion exchange resin modules in low-salt areas. This can achieve: 1) shorten the desalination and purification time and quickly restore the CO2 production of the carbon capture system; 2) reduce the amount of wastewater and alkali consumption, and alleviate the subsequent waste liquid disposal pressure and reagent supply pressure.

[0027] 4. This technical solution can strengthen the online quality assessment of carbon capture organic amine liquid, realize the automatic switching of carbon capture organic amine liquid in various purification modes such as filtration mode, low salt mode, high salt-low salt mode, etc., ensure the quality and absorption capacity of organic amine liquid, and maximize the desalination efficiency, reduce organic amine loss, waste liquid volume and alkali consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a flow chart of the coordinated treatment system for online quality assessment and purification of organic amine liquid in an embodiment of the present invention.

[0029] Figure 2 This is a graph showing the relationship between the electrical conductivity of the organic amine solution and the content of heat-stable salt in the carbon capture system.

[0030] Figure 3 This is a graph showing the relationship between the electrical conductivity of the organic amine liquid in the carbon capture system and the CO2 production and unit heat loss. DETAILED DESCRIPTION

[0031] The following is further described in detail through specific implementations, but the implementation of the present invention is not limited thereto. Unless otherwise specified, the technical means used in the following implementations are conventional means well known to those skilled in the art; the experimental methods used are all conventional methods; the materials, reagents, etc. used can all be obtained from commercial channels.

[0032] The figure marks in the drawings of the specification include: early warning unit 1, filtration unit 2, ion exchange membrane desalination module 3, exchange membrane auxiliary module 4, ion exchange resin desalination module 5, exchange resin auxiliary module 6, 1# control valve 7, 2# control valve 8, 3# control valve 9, 4# control valve 10, 5# control valve 11, 6# control valve 12, 7# control valve 13.

[0033] The embodiment is basically as shown in the attached Figure 1 As shown: a collaborative treatment system for online quality assessment and purification of organic amine liquid, including an early warning unit 1, a filtration unit 2, a desalination unit and an auxiliary unit, wherein the desalination unit includes an ion exchange membrane desalination module 3 and an ion exchange resin desalination module 5.

[0034] The early warning unit 1 is used to monitor and track the thermal stability salt content and suspended matter content in the organic amine liquid in real time. The early warning unit 1 includes a conductivity meter and a turbidity meter, wherein: the conductivity meter is used to reflect the thermal stability salt content; the turbidity meter is used to reflect the suspended matter content, thereby realizing the online quality assessment of the carbon capture organic amine liquid. At the same time, the early warning unit 1 will set the early warning value and the operating value for the conductivity and turbidity. When the detection value exceeds the early warning value, the rear-end organic amine liquid purification unit is started for purification treatment until the detection value of the carbon capture organic amine liquid is lower than the operating value, and then the purification unit will be stopped.

[0035] The filter unit 2 includes two-stage filter modules, and the filter type of the filter module is at least one of bag filtration, pleated filter element filtration, and activated carbon filtration, and the two-stage filter modules are arranged in series. The filtration accuracy of the primary filter module is 10μm, 5μm or 1μm, and the filtration accuracy of the secondary filter module is 1μm or 0.5μm. In this way, the interception accuracy of the secondary filter module is one level higher than that of the primary filter module. The stepped interception accuracy configuration of the two-stage filter module is used to ensure efficient interception of suspended matter of different particle sizes, improve the removal rate of suspended matter, and avoid filter element clogging.

[0036] The desalination unit includes an ion exchange membrane desalination module 3 and an ion exchange resin desalination module 5. The ion exchange membrane desalination module 3 has the advantages of strong desalination capacity, small organic amine loss and small amount of waste liquid under high salt conditions, and can achieve rapid desalination of organic amine liquid; the ion exchange resin desalination module 5 has the advantages of strong desalination capacity, small organic amine loss and thorough desalination under low salt conditions. The two sets of desalination modules can achieve rapid switching of series / parallel connection according to the desalination requirements of the carbon capture system, ensuring the high efficiency of purification and treatment of organic amine liquid.

[0037] There are three purification modes in this system, including filtration mode, low salt mode and high salt-low salt mode. The start and stop conditions of the filtration mode are determined by the early warning unit 1, which sets the early warning value and the operating value for the conductivity and turbidity. When the detection value exceeds the early warning value, the rear-end organic amine liquid purification unit is started for purification; the selection of low salt mode and high salt-low salt mode is determined according to the actual needs of the carbon capture system. If the carbon capture system performs continuous organic amine liquid purification and the thermally stable salt content in the system is kept at a low level, the low salt mode is started; if the carbon capture system performs intermittent organic amine liquid purification (3-4 months / purification), the thermally stable salt content in the system is high, and the high salt-low salt mode is started.

[0038] The auxiliary unit comprises an exchange membrane auxiliary module 4 and an exchange resin auxiliary module 6, which are used to assist and coordinate the desalination unit.

[0039] A collaborative treatment method for online quality assessment and purification of organic amine liquid comprises the following steps:

[0040] Step 1: Online evaluation of organic amine liquid: the early warning unit 1 is connected to the main pipeline of the organic amine liquid, the carbon capture organic amine liquid enters the early warning unit 1, and the conductivity meter and turbidity meter perform online evaluation on the quality of the organic amine liquid.

[0041] Step 2: Mode selection:

[0042] 1. When the turbidity detection value of the warning unit 1 exceeds the set warning value, and the conductivity detection value is lower than the set warning value, only the filtering mode is started:

[0043] Open 1# control valve 7 and 4# control valve 10, and keep 2# control valve 8, 3# control valve 9, 5# control valve 11, 6# control valve 12, and 7# control valve 13 closed. The organic amine liquid enters the filter unit 2 from the bypass, intercepts the suspended matter through the precision filter element to reduce the turbidity, and then the organic amine liquid returns to the carbon capture system, completing the single-cycle filtration and purification of the organic amine liquid.

[0044] When the turbidity detection value of the early warning unit 1 is lower than the set operating value, the purification system is stopped and the 1# control valve 7 and the 4# control valve 10 are closed.

[0045] 2. When the carbon capture system performs intermittent organic amine liquid purification treatment, the high-salt-low-salt mode is adopted. Under this mode, the conductivity detection value of the early warning unit 1 is set with high salt value, low salt value and operating value, and the purification system is efficiently regulated by the conductivity change. The threshold of the conductivity meter of the early warning unit 1 is set as follows: high salt value 5ms / cm, low salt value 3ms / cm, operating value 1.5ms / cm; the threshold of the turbidity meter is set as follows: early warning value 4000NTU, operating value 500NTU.

[0046] 1) When the conductivity detection value of the warning unit 1 exceeds the high salt value, the high salt-low salt mode is activated:

[0047] Open 1# control valve 7, 2# control valve 8, 3# control valve 9, and keep 4# control valve 10, 5# control valve 11, 6# control valve 12, 7# control valve 13 closed. The organic amine liquid enters the filtration unit 2 from the bypass, and enters the ion exchange membrane desalination module 3 after filtration. After desalination and purification, the organic amine liquid returns to the carbon capture system, completing the single-cycle desalination and purification of the organic amine liquid under high salt conditions.

[0048] 2) When the conductivity detection value of the early warning unit 1 is close to the low salt value, the purification system switches from the high salt mode to the low salt mode:

[0049] During the switching process, keep 1# control valve 7 open, 4# control valve 10 and 7# control valve 13 closed, open 5# control valve 11 and 6# control valve 12 in sequence, and close 2# control valve 8 and 3# control valve 9. The organic amine liquid enters the filtration unit 2 from the bypass, and enters the ion exchange resin desalination module 5 after switching. After desalination and purification, the organic amine liquid returns to the carbon capture system, completing the single-cycle desalination and purification of the organic amine liquid under low-salinity conditions.

[0050] 3) When the conductivity detection value of the early warning unit 1 is lower than the operating value, the purification system is stopped:

[0051] First, close the 1# control valve 7, 4# control valve 10, and 7# control valve 13; at the same time, start the auxiliary units (exchange membrane auxiliary module 4, exchange resin auxiliary module 6) of the ion exchange membrane desalination module 3 and the ion exchange resin desalination module 5, and after completing the regeneration and cleaning of the two sets of desalination modules, close the 2# control valve 8, 3# control valve 9, 5# control valve 11, and 6# control valve 12 to complete the shutdown of the purification system.

[0052] 3. If the carbon capture system performs continuous organic amine liquid purification treatment, a low-salt mode is adopted. Under this mode, the conductivity meter of the early warning unit 1 is set with a low-salt value and an operating value, and efficient regulation of the purification system is achieved through changes in conductivity.

[0053] 1) When the conductivity detection value of the early warning unit 1 exceeds the low salt value, the low salt mode is started: open the 1# control valve 7, 5# control valve 11, and 6# control valve 12, and keep the 2# control valve 8, 3# control valve 9, 4# control valve 10, and 7# control valve 13 closed. The organic amine liquid enters the filtration unit 2 from the bypass, and then enters the ion exchange resin desalination module 5 after filtration. After desalination and purification, the organic amine liquid returns to the carbon capture system, completing the single-cycle desalination and purification of the organic amine liquid under low salt conditions.

[0054] 2) In low-salt mode, purified waste liquid is generated during the operation of the ion exchange resin desalination module 5. The purified waste liquid is deeply treated by the ion exchange membrane desalination module 3, which can reduce the waste liquid by more than 50%. Keep the 1# control valve 7, 5# control valve 11, and 6# control valve 12 open, the 2# control valve 8 and 4# control valve 10 closed, and open the 7# control valve 13 and 3# control valve 9 in sequence. The purified waste liquid enters the ion exchange membrane desalination module 3 through the 7# control valve 13. After desalination treatment, the fresh water returns to the carbon capture system for reuse, and the concentrated water is discharged from the purification system.

[0055] 3) When the conductivity detection value of the early warning unit 1 is lower than the operating value, the purification system is stopped. First, close the 1# control valve 7 and the 4# control valve 10; then start the auxiliary system of the ion exchange membrane desalination module 3 and the ion exchange resin desalination module 5, and after completing the regeneration and cleaning of the two desalination modules, close the 2# control valve 8, the 3# control valve 9, the 5# control valve 11, the 6# control valve 12, and the 7# control valve 13 to complete the shutdown of the purification system.

[0056] Step 3: Collect the purified carbon capture organic amine solution to test the thermal stability salt content and suspended matter content.

[0057] Example 1 Filtration Mode

[0058] In this embodiment, the threshold values ​​of the conductivity meter and turbidity meter in the early warning unit are set as follows: conductivity meter: high salt value (5ms / cm), low salt value (3ms / cm), operating value (1.5ms / cm); turbidity meter: early warning value (4000NTU), operating value (500NTU).

[0059] During the operation of the carbon capture system, the early warning unit conducts real-time detection and evaluation of the quality of the organic amine liquid. During the process, the organic amine liquid indicators are tested. The test results are: the conductivity is 1.2ms / cm, and the turbidity is 4017NTU. According to the built-in instructions of the purification system (the conductivity detection value is lower than the operating value, and the turbidity detection value exceeds the early warning value), the purification system starts the filtration mode.

[0060] When the filtration is turned on, the interception accuracy of the two-stage filtration module of the filtration unit is configured to 5μm+1μm. After 9 days of continuous filtration and purification, as shown in Table 1, the turbidity of the organic amine liquid dropped from 4017NTU to 1032NTU, showing a trend of fast initial decline rate and slow decline rate in the later period. In order to speed up the decline rate, the interception accuracy configuration of the two-stage filtration module was adjusted to 1μm+0.5μm, and the filtration and purification was continued for 4 days. The turbidity of the organic amine liquid dropped from 1032NTU to 489NTU, which was lower than the operating value of 500NTU set by the early warning unit, and the purification process was stopped at this time.

[0061] The purified carbon capture organic amine liquid was collected for suspended matter content detection. The detection method was based on GB 11901-89: Determination of suspended matter in water (gravimetric method). The detection result was 0.08%, which met the requirements of filtration purification (suspended matter content <0.1%).

[0062] Table 1 Changes in turbidity of organic amine solution after purification

[0063]

[0064]

[0065] Example 2 High Salt-Low Salt Mode

[0066] In this embodiment, the threshold values ​​of the conductivity meter and turbidity meter in the early warning unit are set as follows: conductivity meter: high salt value (5ms / cm), low salt value (3ms / cm), operating value (1.5ms / cm); turbidity meter: early warning value (4000NTU), operating value (500NTU).

[0067] During the operation of the carbon capture system, the early warning unit conducts real-time detection and evaluation of the quality of the organic amine liquid. The detection results for a certain period of time are: the conductivity is 5.0ms / cm and the turbidity is 3440NTU. According to the built-in instructions of the purification system (the conductivity detection value exceeds the high salt value), the purification system starts the high salt-low salt mode.

[0068] When the purification is turned on, the desalination unit first calls the ion exchange membrane desalination module to process the organic amine solution under high salt conditions. After 9 days of continuous desalination and purification, as shown in Table 2: the conductivity of the organic amine solution is reduced from 5.0ms / cm to 3.0ms / cm. Since the conductivity detection value is equal to the set low salt value, the purification switching instruction is triggered at this time, and the desalination unit switches the ion exchange membrane desalination module to the ion exchange resin desalination module. After continuing to purify with this desalination module for 10 days, the conductivity is reduced from 3.0ms / cm to 1.4ms / cm, which is lower than the operating value of 1.5ms / cm set by the early warning unit. At this time, the purification process is stopped. At the same time, in the high-salt-low-salt mode purification, the interception accuracy of the two-stage filtration module of the filtration unit is configured to 5μm+1μm (to ensure a high pass rate of the organic amine solution), and the turbidity of the organic amine solution is reduced from 3440NTU to 723NTU.

[0069] The purified carbon capture organic amine solution was collected for thermal stability salt content and suspended matter content testing. Among them, the thermal stability salt content in the organic amine solution was tested by ion chromatography, and the test result was 0.91%, which met the purification requirements (thermal stability salt content <1.0%); the suspended matter content was tested in accordance with GB 11901-89: Determination of suspended matter in water quality (gravimetric method), and the test result was 0.15%.

[0070] Table 2 Changes in turbidity and conductivity of organic amine solution after purification

[0071] time Turbidity (NTU) Conductivity (ms / cm) Day 1 3440 5.0 Day 2 3070 4.6 Day 3 2735 4.3 Day 4 2334 4.0 Day 5 1984 3.8 Day 6 1681 3.5 Day 7 1424 3.3 Day 8 1266 3.1 Day 9 1076 3.0 Day 10 953 2.8 Day 11 928 2.6 Day 12 897 2.4 Day 13 871 2.2 Day 14 866 2.0 Day 15 843 1.9 Day 16 805 1.7 Day 17 770 1.6 Day 18 745 1.5 Day 19 723 1.4

[0072] In addition, under the organic amine liquid conditions of Example 2, a comparative example (single ion exchange membrane purification, ion exchange resin purification treatment) was set up. Through comparative analysis with single ion exchange membrane purification and ion exchange resin purification treatment, the improvement effect brought about by the purification of this patent (high salt-low salt mode) was obtained: purification time was shortened by 24%, the amount of purified waste liquid was reduced by 50%, the alkali consumption was reduced by 46.7%, and the organic amine loss continued to maintain a low level of 1%.

[0073] Table 3 Comparison of purification effects (high salt-low salt mode) with single ion exchange membrane purification and ion exchange resin purification

[0074]

[0075] Example 3 Low Salt Mode

[0076] In this embodiment, the threshold values ​​of the conductivity meter and turbidity meter in the early warning unit are set as follows: conductivity meter: high salt value (5ms / cm), low salt value (3ms / cm), operating value (1.5ms / cm); turbidity meter: early warning value (4000NTU), operating value (500NTU).

[0077] During the operation of the carbon capture system, the early warning unit conducts real-time detection and evaluation of the quality of the organic amine liquid. The detection results for a certain period of time are: conductivity is 2.0ms / cm, turbidity is 1437NTU. According to the built-in instructions of the purification system (the conductivity detection value exceeds the low salt value), the purification system starts the low salt mode.

[0078] When the purification is turned on, the desalination unit calls the ion exchange resin desalination module to treat the organic amine liquid. After 6 days of continuous desalination and purification, the conductivity detection value of the organic amine liquid drops from 2.0ms / cm to 1.5ms / cm, which is lower than the set operating value of the early warning unit of 1.5ms / cm. At this time, the purification process is stopped. At the same time, in the low-salt mode purification, the interception accuracy of the two-stage filter module of the filtration unit is configured to 5μm+1μm (to ensure a high pass rate of the organic amine liquid), and the turbidity of the organic amine liquid drops from 1437NTU to 951NTU.

[0079] The purified carbon capture organic amine solution was collected for thermal stability salt content and suspended matter content testing. Among them, the thermal stability salt content in the organic amine solution was tested by ion chromatography, and the test result was 0.99%, which met the purification requirements (thermal stability salt content <1.0%); the suspended matter content was tested in accordance with GB 11901-89: Determination of suspended matter in water quality (gravimetric method), and the test result was 0.19%.

[0080] Table 4 Changes in turbidity and conductivity of organic amine solution after purification

[0081] time Turbidity (NTU) Conductivity (ms / cm) Day 1 1437 2.0 Day 2 1320 1.9 Day 3 1176 1.8 Day 4 1068 1.7 Day 5 983 1.6 Day 6 951 1.5

[0082] In addition, an ion exchange membrane desalination module is used to deeply desalinate the purified waste liquid of the ion exchange resin. The fresh water quality meets the reuse requirements, and the concentrated water is discharged and disposed of. The amount of waste liquid is reduced by more than 50%, with significant environmental benefits.

[0083] Experimental Example 1 Turbidity threshold optimization experiment

[0084] With reference to the industry standard SY / T 6538-2016 "Formulated Selective Desulfurization Solvent", an organic amine liquid foaming test experiment was carried out to obtain the foaming height and defoaming time of the organic amine liquid at different suspended matter contents.

[0085] With reference to the national standard GB / T 11901-1989 “Determination of suspended matter in water by gravimetric method”, the suspended matter content of organic amine liquid was tested to obtain the suspended matter content of organic amine liquid corresponding to different turbidity data in the carbon capture system.

[0086] Experimental method: By collecting organic amine liquid corresponding to different turbidity data from the carbon capture system, and then using the corresponding test standards to obtain experimental data such as suspended matter content, solution foaming height, defoaming time, etc., and then matching it with whether solution foaming, tower flooding, pressure fluctuations and other phenomena occur during the operation of the carbon capture system, finally, a reasonable control value of the turbidity of the organic amine liquid is obtained to ensure that the carbon capture system operates under better working conditions.

[0087] The experimental results are shown in Table 5: when the turbidity of the organic amine liquid in the carbon capture system is below 3492NTU, the organic amine liquid has no foaming, tower flooding and other phenomena, the system operates normally, and the CO2 production does not change; when the turbidity of the organic amine liquid in the carbon capture system is 4017NTU, the organic amine liquid begins to flood the tower, the tower pressure fluctuates greatly, and the CO2 production fluctuates slightly; when the turbidity of the organic amine liquid in the carbon capture system is 4589NTU, the organic amine liquid frequently floods the tower, the tower pressure fluctuates greatly, the gas-liquid mass transfer efficiency decreases, the system operation is unstable, and the CO2 production decreases significantly.

[0088] Therefore, under the premise of comprehensively considering the efficient and stable operation of the carbon capture system, the turbidity warning value of the organic amine liquid of the early warning system is set to 4000NTU and the operating value is set to 500NTU.

[0089] Table 5

[0090]

[0091]

[0092] Experimental Example 2 Conductivity Threshold Optimization Experiment

[0093] The determination of the conductivity threshold focuses on data including heat-stable salt content, system CO2 production, unit heat consumption, amine loss, etc. Among them, the heat-stable salt content is determined by cationic resin-acid-base titration method; the system CO2 production, unit heat consumption, and amine loss data are obtained in real time through the carbon capture system.

[0094] Experimental method: By collecting organic amine liquid corresponding to different conductivity data from the carbon capture system, and then testing to obtain the heat-stable salt content, and then matching it with the system CO2 production, unit heat consumption, amine loss and other data, finally obtaining a reasonable control value of the conductivity of the organic amine liquid to ensure that the carbon capture system operates under better working conditions.

[0095] The experimental results are shown in Table 6 and Figure 2 As shown in the test data, the conductivity of the organic amine liquid in the carbon capture system is positively correlated with the test results of the heat-stable salt content, that is, as the conductivity gradually increases, the corresponding test results of the heat-stable salt content also increase. Therefore, the online conductivity data can be used to quantitatively determine the level of heat-stable salt content, realize the quality monitoring of the organic amine liquid in the carbon capture system, and serve as a control instruction for the purification system.

[0096] Among them, when the conductivity is 1.5ms / cm, the corresponding thermally stable salt content test result is 1.03%. According to the industrial operation regulations of the carbon capture system, it is more reasonable to control the thermally stable salt content of the organic amine liquid below 1.0%. Therefore, the conductivity operation value of the early warning system is set to 1.5ms / cm.

[0097] According to industrial application experience, the ion exchange membrane desalination module has high desalination efficiency and fast delay speed when the heat-stable salt content is >2.0%, but when the heat-stable salt content is lower than 2.0%, its performance will drop rapidly, while the ion exchange resin desalination module is not affected by the heat-stable salt content. Therefore, the heat-stable salt content of 2.0% is the switching control line of the ion exchange membrane module and the ion exchange resin module, and the corresponding conductivity is about 3.0ms / cm. Therefore, the conductivity operation value of the early warning system is set to 3.0ms / cm.

[0098] like Figure 3 As shown in the figure, according to the data, as the conductivity of the organic amine liquid in the carbon capture system increases, the system CO2 production gradually decreases, and the unit heat consumption gradually increases. Among them, when the conductivity of the early warning system is lower than 5.0ms / cm, the system CO2 production and unit heat consumption both change linearly; but when the conductivity is greater than 5.0ms / cm, the system CO2 production drops significantly and the unit heat consumption increases significantly. Therefore, in order to ensure the system CO2 production and unit heat consumption, the high salt value of the conductivity of the early warning system is set to 5.0ms / cm.

[0099] Table 6

[0100]

[0101] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A collaborative treatment system for online quality assessment and purification of organic amine liquid, characterized by: It includes an early warning unit, a filtering unit and a desalination unit. The desalination unit includes an ion exchange membrane desalination module and an ion exchange resin desalination module.

2. The coordinated treatment system for online quality assessment and purification of organic amine liquid according to claim 1, characterized in that: The early warning unit includes a conductivity meter and a turbidity meter.

3. The coordinated treatment system for online quality assessment and purification of organic amine liquid according to claim 2, characterized in that: The filter unit comprises two-stage filter modules, and the two-stage filter modules are arranged in series.

4. The coordinated treatment system for online quality assessment and purification of organic amine liquid according to claim 3, characterized in that: The filtering type of the two-stage filtering module is at least one of bag filtering, pleated filter element filtering, and activated carbon filtering.

5. The coordinated treatment system for online quality assessment and purification of organic amine liquid according to claim 4, characterized in that: The filtering accuracy of the primary filtering module and the secondary filtering module is set in a gradient manner. The filtering accuracy of the primary filtering module is 10μm, 5μm or 1μm, and the filtering accuracy of the secondary filtering module is 1μm or 0.5μm.

6. A collaborative treatment method for online quality assessment and purification of organic amine liquid, characterized in that: The method is accomplished by using the system described in any one of claims 1 to 5, comprising the following steps: Step 1: Online evaluation of organic amine liquid: The organic amine liquid enters the early warning unit, and the conductivity meter and turbidity meter conduct online evaluation of the quality of the organic amine liquid; Step 2: Mode selection:

1. When the turbidity detection value of the warning unit exceeds the set warning value, and the conductivity detection value is lower than the set warning value, only the filtering mode is started; 2. When the carbon capture system performs intermittent organic amine liquid purification treatment, the high-salt-low-salt mode is adopted; the conductivity detection value of the early warning unit is set with a high-salt value, a low-salt value and an operating value, and the purification system is efficiently regulated by the conductivity change; when the conductivity detection value of the early warning unit exceeds the high-salt value, the high-salt-low-salt mode is started; when the conductivity detection value of the early warning unit is close to the low-salt value, the purification system switches from the high-salt mode to the low-salt mode; 3. When the carbon capture system is undergoing continuous organic amine liquid purification treatment, the low-salt mode is adopted; when the conductivity detection value of the early warning unit is lower than the operating value, the system is shut down.

7. The method for online quality assessment and purification of an organic amine solution according to claim 6, characterized in that: The threshold settings of the conductivity meter of the early warning unit are as follows: high salt value 5ms / cm, low salt value 3ms / cm, and operating value 1.5ms / cm.

8. The method for online quality assessment and purification of an organic amine solution according to claim 7, characterized in that: The thresholds of the turbidity meter of the warning unit are set as follows: warning value 4000NTU, operating value 500NTU.

9. The method for online quality assessment and purification of an organic amine solution according to claim 8, characterized in that: The method also includes step three, collecting the purified carbon capture organic amine liquid to test the thermal stability salt content and suspended matter content.

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