Evaluation method and evaluation device for decarburization solvent

Abstract

The invention relates to the technical field of decarburization solvent evaluation. The invention relates to a decarburization solvent evaluation method, which comprises: (1) carrying out an absorption reaction on a decarburization solvent and a CO2-containing gas mixture to obtain a decarburization solvent rich solution, collecting the decarburization solvent rich solution when the reaction time is t, measuring the load of CO2 in the decarburization solvent rich solution, recording the load as L, and stopping the reaction when the decarburization solvent absorbs CO2 to achieve a saturation state; (2) carrying out regeneration reaction on the rich solution of the decarburization solvent in the step (1), collecting the regenerated decarburization solvent, measuring the load of residual CO2 in the regenerated decarburization solvent, and recording the load as Lr; and (3) calculating the regeneration degree R of the decarburization solvent, and evaluating the decarburization solvent according to the load L of CO2 in the rich solution of the decarburization solvent and the regeneration degree R. According to the evaluation method of the decarburization solvent, the two indexes of CO2 load and regeneration degree of the decarburization solvent are integrated, the advantages and disadvantages of the decarburization solvent can be visually reflected, and the evaluation result is more comprehensive and reasonable.

Description

Technical Field

[0001] This invention relates to the field of decarbonization solvent evaluation technology, and specifically to a decarbonization solvent evaluation method and device. Background Technology

[0002] Chemical absorption is currently the most mature CO2 capture process. The decarbonization solvent is the core of this technology and is fundamental to reducing energy consumption and cost. An efficient decarbonization solvent should possess characteristics such as rapid absorption rate, high CO2 load, and easy desorption and regeneration. Common decarbonization solvent components include organic alcohol amines, organic amines, amino acid salts, hindered amines, and ionic liquids. In practical applications, hundreds or even thousands of decarbonization solvents need to be optimized and combined to adapt to different CO2 sources and decarbonization conditions. How to quickly and accurately screen out high-performance decarbonization solvents is a technical problem that urgently needs to be solved by those skilled in the art.

[0003] GB / T 36767-2018 provides a method for evaluating the purification performance of alkanolamine-based decarbonization solvents. This method characterizes the purification performance of the solvent by measuring the CO2 content in the purified gas. However, this evaluation method lacks clear evaluation indicators and does not cover key indicators of the decarbonization solvent, such as CO2 saturation loading, CO2 absorption rate, and regeneration performance, resulting in inaccurate evaluation results. Furthermore, the evaluation equipment involved in this method is relatively large, with tower heights exceeding 4 meters, and it is limited to the evaluation of alkanolamine-based decarbonization solvents, failing to evaluate high-viscosity decarbonization solvents such as ionic liquids.

[0004] Therefore, there is an urgent need in the existing technology for an accurate, rapid, and practical method for evaluating decarbonization solvents. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention proposes a method and apparatus for evaluating decarbonization solvents.

[0006] In a first aspect, the present invention proposes a method for evaluating decarbonization solvents, the evaluation method comprising the following steps:

[0007] (1) A CO2-containing mixed gas reacts with a decarbonization solvent to obtain a decarbonization solvent-rich solution. When the reaction time is t, the decarbonization solvent-rich solution is collected and the CO2 load in the decarbonization solvent-rich solution is measured and recorded as L. When the decarbonization solvent absorbs CO2 to the saturation state, the reaction is stopped.

[0008] (2) The decarbonization solvent rich solution collected in step (1) is subjected to a regeneration reaction. The regenerated decarbonization solvent is collected, and the load of residual CO2 in the regenerated decarbonization solvent is measured and recorded as Lr.

[0009] (3) Calculate the regeneration degree R of the decarbonization solvent.

[0010] The decarbonization solvent is evaluated by the CO2 load L in the decarbonization solvent-rich solution and the decarbonization solvent regeneration degree R.

[0011] Specifically, under the same evaluation conditions, the higher the CO2 load L in the decarbonization solvent rich solution, the stronger the CO2 absorption capacity of the decarbonization solvent; and the higher the decarbonization solvent regeneration degree R, the better the regeneration performance of the decarbonization solvent.

[0012] Specifically, in this invention, when the CO2 content in the CO2-containing gas mixture after reaction with the decarbonization solvent is close to the CO2 content in the CO2-containing gas mixture before reaction, it is considered that the decarbonization solvent has reached saturation in absorbing CO2. The CO2 content in the CO2-containing gas mixture before reaction is denoted as W1, and the CO2 content in the CO2-containing gas mixture after reaction with the decarbonization solvent is denoted as W2. Those skilled in the art generally believe that when the value of (W1-W2) / W1 is within 3%, the decarbonization solvent has reached saturation in absorbing CO2.

[0013] Specifically, in this invention, the decarbonized solvent-rich solution obtained at reaction times t of 1 min, 3 min, 5 min, 10 min, and when the decarbonized solvent is saturated can be used for the regeneration reaction. Preferably, the decarbonized solvent-rich solution collected at a reaction time t of 5 min is used for the regeneration reaction.

[0014] In a specific embodiment of the present invention, the CO2-containing gas mixture passes through a decarbonization solvent in the form of bubbles, forming a mixture of the CO2-containing gas mixture and the decarbonization solvent, denoted as a gas-liquid mixture. When the gas content ε of the gas-liquid mixture is stable, the volume of the gas-liquid mixture per unit volume is denoted as V. 混 Calculate V 混 The surface area of ​​all the bubbles in the middle is denoted as S, and S / V 混 Let α be the value of CO2 absorption by the decarbonization solvent. The decarbonization solvent is evaluated by the rate ν.

[0015] Specifically, the CO2-containing mixed gas in this invention contains N2, CO2 and O2. When the N2 content in the CO2-containing mixed gas before and after decarbonization is the same, the gas content ε in the decarbonization solvent can be considered to be in a stable state. Alternatively, the CO2-containing mixed gas can be introduced into the decarbonization solvent through a pipeline. When the pressure in the pipeline remains unchanged, the gas content ε in the decarbonization solvent can be considered to be in a stable state.

[0016] As a specific embodiment of the present invention, in step (1), with the volume of the decarbonization solvent being 200 mL, the flow rate of the CO2-containing mixed gas is 50-1000 mL / s; preferably 150-650 mL / s. The present invention can control the gas content ε by controlling the flow rate of the CO2-containing mixed gas. Specifically, the change in the liquid level of the absorption reactor before and after the CO2-containing mixed gas is introduced is measured to obtain the gas content ε. For example, for an absorption reactor with a height-to-diameter ratio of 10:1 and an inner diameter (including equivalent) of 30 mm, by adjusting the flow rate of the CO2-containing mixed gas, when the CO2-containing mixed gas is stably introduced into the decarbonization solvent, the gas content ε in the decarbonization solvent can be maintained at 6%.

[0017] In a specific embodiment of the present invention, in step (1), the CO2-containing mixed gas passes through the decarbonization solvent in the form of bubbles, with the bubble diameter being 50–150 μm; preferably 90–110 μm. Passing the CO2-containing mixed gas through the decarbonization solvent in the form of bubbles increases the contact area between the CO2-containing mixed gas and the decarbonization solvent, weakening the influence of mass transfer factors; furthermore, the reaction of the CO2-containing mixed gas with the decarbonization solvent in the form of bubbles of uniform particle size facilitates the calculation of the value of α.

[0018] Specifically, when the diameter of the bubble is 100 μm, the volume of the sphere is V = 4 / 3πR. 3 The volume V of each bubble can be obtained. q Then, from a unit volume of gas-liquid mixture V 混 Multiplying by the gas content ε of the gas-liquid mixture yields the total volume V of the bubbles in the gas-liquid mixture. 气泡 V 气泡 =V 混 ×ε, from V q and V 气泡 The number of bubbles n in the gas-liquid mixture can be obtained, where n = V. 气泡 / V q The surface area S of all bubbles in the gas-liquid mixture can be obtained from the number n of bubbles and the diameter of the bubbles (based on the bubble diameter, S0 = 4πR). 2 The surface area S0 of each bubble (S = n × S0) is obtained from the total surface area S of all bubbles in the gas-liquid mixture, and the volume V. 混 α can then be obtained, where α = S / V 混 .

[0019] As a specific embodiment of the present invention, L is measured by reverse titration;

[0020] Specifically, L was measured using a standard Ca(OH)₂ aqueous solution back titration method.

[0021] Where V0 is the volume of the standard Ca(OH)2 aqueous solution;

[0022] c0 is the concentration of the standard Ca(OH)2 aqueous solution;

[0023] V1 is the titration volume of the decarbonized solvent-rich solution collected at reaction time t.

[0024] As a specific embodiment of the present invention, L is measured by reverse titration. r ;

[0025] Specifically, L was measured using a standard Ca(OH)₂ aqueous solution back titration method. r ,

[0026] Where V0 is the volume of the standard Ca(OH)2 aqueous solution;

[0027] c0 is the concentration of the standard Ca(OH)2 aqueous solution;

[0028] V 1r This is the titration volume of the regenerated decarbonized solvent.

[0029] Specifically, the back titration method in this invention refers to titrating a rich solution of decarbonized solvent or a regenerated decarbonized solvent into a standard Ca(OH)2 aqueous solution.

[0030] As a specific embodiment of the present invention, the CO2 content in the CO2-containing gas mixture is 10v% to 30v%.

[0031] Specifically, the CO2-containing gas mixture includes O2, CO2, and N2, with O2, CO2, and N2 volume fractions of 5.0 v%–8.0 v%, 12.0 v%–16 v%, and 76 v%–83 v%, respectively.

[0032] As a specific embodiment of the present invention, the conditions for the reaction of the CO2-containing mixed gas with the decarbonization solvent include: a pressure of 5 to 100 kPa gauge pressure and a temperature of 20 to 30°C; preferably, the pressure is 10 to 20 kPa gauge pressure.

[0033] As a specific embodiment of the present invention, the conditions for the regeneration reaction include: a temperature of 90 to 120°C, a pressure of atmospheric pressure, and a time of 5 to 10 minutes.

[0034] Specifically, the regeneration reaction temperature can be 90℃, 100℃, 110℃, and 120℃. The regeneration reaction time is preferably 5 minutes. When evaluating different decarbonization solvents, the comparison of the degree of regeneration R needs to be conducted under the same regeneration temperature and time constraints.

[0035] As a specific embodiment of the present invention, the decarbonization solvent is selected from one or more of alkanolamines, ionic liquids, amino acid salts, and sterically hindered amines.

[0036] Preferably, the alcohol amine is selected from one or more of primary alcohol amines, secondary alcohol amines, tertiary alcohol amines, and derivatives of primary alcohol amines, secondary alcohol amines, and tertiary alcohol amines;

[0037] The ionic liquid is selected from one or more of imidazole ionic liquids, pyridinyl ionic liquids, quaternary ammonium salt ionic liquids, piperidine ionic liquids and pyrrolidine ionic liquids;

[0038] The amino acid salt is selected from one or more of the alkali metal salts of amino acids, and is more preferably selected from one or more of sodium glycinate, potassium glycinate, sodium alanine, potassium alanine, sodium lysine, and potassium lysine.

[0039] The hindered amine is selected from one or more of 2-amino-2-methyl-1-propanol, tert-butylaminoethoxyethanol, and 1,3-di(dimethylamino)-2-propanol.

[0040] In a specific embodiment of the present invention, in step (1), the reaction time t is greater than or equal to 1 min; the reaction time t is less than or equal to the time required for the decarbonization solvent to become saturated. Specifically, the reaction time t can be selected from 1 min, 3 min, 5 min, 10 min, and the time required for the decarbonization solvent to become saturated. The selection of the reaction time in the present invention coincides with the actual application time of the decarbonization solvent in industry. When evaluating the decarbonization solvent, it is necessary to compare the CO2 load L in the rich solution of different decarbonization solvents under the same time t.

[0041] In a specific embodiment of the present invention, L includes: the amount of free CO2 in the decarbonization solvent-rich solution and the amount of CO2 participating in the reaction. Specifically, the CO2 load L in the decarbonization solvent-rich solution includes, but is not limited to, the amounts of CO2, carbonate, and bicarbonate. That is, the CO2 load L in the decarbonization solvent-rich solution is the amount of CO2 absorbed by the decarbonization solvent.

[0042] As a specific embodiment of the present invention, L r This includes the amount of residual free CO2 in the regenerated decarbonization solvent and the amount of CO2 that participates in the reaction. Specifically, the CO2 loading L in the regenerated decarbonization solvent... r This includes, but is not limited to, the amounts of CO2, carbonate, and bicarbonate.

[0043] Secondly, the present invention provides an evaluation apparatus for the decarbonization solvent evaluation method provided in the first aspect of the present invention. The evaluation apparatus includes: a decarbonization solvent CO2 absorption device and a decarbonization solvent regeneration device.

[0044] The decarbonization solvent CO2 absorption device includes: a CO2-containing mixed gas storage tank, a gas source control valve, an inlet CO2 gas detector, an inlet gas flow meter, a pressure gauge, an absorption reactor, an outlet CO2 gas detector, and an outlet gas flow meter; the CO2-containing mixed gas storage tank is connected to the inlet of the absorption reactor via pipeline I, and the gas source control valve, the inlet CO2 gas detector, the inlet gas flow meter, and the pressure gauge are installed on pipeline I; the gas in the absorption reactor is discharged through pipeline II, and the outlet CO2 gas detector and the outlet gas flow meter are installed on pipeline II;

[0045] The absorption reactor is equipped with a bubble distributor at the air inlet, a demister at the air outlet, and a decarbonization solvent sampling port.

[0046] Specifically, the process of CO2 absorption by the decarbonization solvent of the present invention includes: injecting the decarbonization solvent into the absorption reactor, and drawing out the CO2-containing mixed gas from the CO2-containing mixed gas storage tank. The CO2 mixed gas in pipeline I is dispersed into bubbles by a bubble distributor and then enters the absorption reactor. In the absorption reactor, the CO2 mixed gas reacts with the decarbonization solvent in the form of bubbles, and the reacted mixed gas is discharged through pipeline II after gas-liquid separation by a demister.

[0047] Specifically, the gas source control valve is used to control the opening and closing of the CO2 gas source. Specifically, the gas source control valve can be either a ball valve or a shut-off valve.

[0048] Specifically, the imported CO2 gas detector is used to detect the CO2 content in the CO2-containing gas mixture before it enters the absorption reactor; the imported CO2 gas detector is an online CO2 gas detector, model FIX550-CO2, with an accuracy of 0.1%.

[0049] Specifically, the imported gas flow meter is used to detect and regulate the flow rate of the CO2-containing gas mixture entering the absorption reactor;

[0050] Specifically, the pressure gauge is used to detect the pressure in pipeline I;

[0051] Specifically, the outlet CO2 gas detector is used to detect and regulate the CO2 content in the gas discharged from the absorption reactor; the outlet CO2 gas detector is an online CO2 gas detector, model FIX550-CO2, with an accuracy of 0.1%.

[0052] Specifically, the outlet gas flow meter is used to display and control the flow rate of gas discharged from the absorption reactor.

[0053] Specifically, the bottom of the absorption reactor can be circular, square, elliptical, or other polygonal, with a height-to-diameter ratio of 10:1, an inner diameter (including equivalent) of 30mm, a smooth inner surface, and resistance to acids and alkalis. It can be made of glass.

[0054] Specifically, the bubble distributor is a sintered metal porous distributor with an outer diameter of 30 mm, threadedly connected to the absorption reactor; the sintered metal can be stainless steel, titanium alloy, Ni-Cu alloy, or Ni-Cr-Fe alloy.

[0055] Specifically, the demister material can be non-woven fabric, PP cotton (man-made chemical fiber), or metal wire mesh, and it is fixed at the outlet of the absorption reactor.

[0056] The CO2 decarbonization solvent regeneration device includes a regeneration reactor, a temperature control device, and a sampler; the regeneration reactor is used to carry out the regeneration reaction of the decarbonization solvent, and the temperature control device is used to control the temperature of the regeneration reactor.

[0057] Specifically, a three-necked flask is used as the regeneration reactor, with the main port serving as the outlet for regenerated CO2, and the other two secondary ports housing a thermometer and a sampler, respectively. The sampler is used to collect the decarbonization solvent in the regeneration reactor, and the thermometer is used to measure the temperature inside the regeneration reactor.

[0058] Specifically, the control device includes a constant temperature heater and a temperature-controlled thermocouple.

[0059] Specifically, a reflux condenser is installed in the main orifice. The purpose of the reflux condenser is to remove the decarbonized solvent generated during the reflux regeneration process. Specifically, the reflux condenser includes a cooling medium outlet, a cooling medium inlet, and a CO2 gas outlet.

[0060] In a specific embodiment of the present invention, the pore size of the bubble distributor is 50–150 μm; preferably 90–110 μm. Specifically, the pore size of the bubble distributor is 100 μm, in which case the CO2 mixture forms bubbles with a diameter of 100 μm after passing through the bubble distributor.

[0061] Compared with the prior art, the present invention has the following beneficial effects.

[0062] This invention provides a method for evaluating decarbonization solvents. The method integrates two indicators—CO2 load and regeneration rate—of the decarbonization solvent, providing a direct reflection of its quality and resulting in a more comprehensive and reasonable evaluation.

[0063] The decarbonization solvent evaluation method of the present invention also includes a CO2 absorption rate index, which can evaluate the CO2 absorption effect of the decarbonization solvent from different time dimensions. The evaluation results are more in line with industrial practice, providing a scientific and rapid evaluation method for the development of decarbonization solvents.

[0064] The evaluation method of this invention has a wide range of applications and can evaluate a variety of decarbonization solvents such as alkanolamines, ionic liquids, amino acid salts, and sterically hindered amines.

[0065] The evaluation method provided by this invention has accurate results, small errors, and strong repeatability. Attached Figure Description

[0066] Figure 1 This is a schematic diagram of one embodiment of the CO2 absorption device for decarbonization solvent of the present invention;

[0067] Figure 2 This is a schematic diagram of one embodiment of the decarbonization solvent regeneration device of the present invention;

[0068] The components are: 1-CO2 mixed gas storage tank; 2-gas source control valve; 3-inlet CO2 gas detector; 4-inlet gas flow meter; 5-outlet CO2 gas detector; 6-outlet gas flow meter; 7-demister; 8-absorption reactor; 9-bubble distributor; 10-sampling port; 11-pressure gauge.

[0069] 12-Regeneration reactor, 13-Sampler, 14-Reflux condenser, 15-Thermometer; 16-Constant temperature heater, 17-Temperature-controlled thermocouple, 18-CO2 gas outlet, 19-Cooling medium outlet, 20-Cooling medium inlet.

[0070] 201-Pipeline I, 202-Pipeline II. Detailed Implementation

[0071] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0072] In this embodiment, the CO2-containing mixed gas is simulated flue gas, in which the volume fractions of O2, CO2, and N2 are 6.0%, 14.0%, and 80%, respectively.

[0073] Examples of the embodiments include Figure 1 and Figure 2 The decarbonization solvent evaluation device shown is comprised of a decarbonization solvent CO2 absorption device and a decarbonization solvent regeneration device.

[0074] The decarbonization solvent CO2 absorption device includes: a CO2 mixed gas storage tank 1, a gas source control valve 2, an inlet CO2 gas detector 3, an inlet gas flow meter 4, an outlet CO2 gas detector 5, an outlet gas flow meter 6, an absorption reactor 8, and a pressure gauge 11; the CO2 mixed gas storage tank 1 is connected to the inlet of the absorption reactor 8 via pipeline I201, and the gas source control valve 2, the inlet CO2 gas detector 3, the inlet gas flow meter 4, and the pressure gauge 11 are installed on pipeline I201; the gas in the absorption reactor is discharged through pipeline II202, and the outlet CO2 gas detector 3 and the outlet gas flow meter 6 are installed on pipeline II202;

[0075] The absorption reactor 8 is equipped with a bubble distributor 9 at the air inlet, a demister 7 at the air outlet, and a decarbonization solvent sampling port 10. The bottom of the absorption reactor 8 is circular with a height-to-diameter ratio of 10:1 and an inner diameter (including equivalent) of 30 mm. The absorption reactor 8 is made of glass.

[0076] The bubble distributor is a sintered metal porous distributor with an outer diameter of 30mm, threadedly connected to the absorption reactor; the bubble distributor is made of stainless steel.

[0077] The demister is made of PP cotton.

[0078] The CO2 decarbonization solvent regeneration device includes a regeneration reactor 12, a temperature control device, and a sampler 13. The regeneration reactor 12 is used for the regeneration reaction of the decarbonization solvent, and the temperature control device is used to control the temperature of the regeneration reactor. The control device includes a constant temperature heater 16 and a temperature-controlled thermocouple 17.

[0079] The regeneration reactor 12 is a three-necked flask, with the main port serving as the CO2 regeneration outlet, and the other two auxiliary ports housing a thermometer 15 and a sampler 13, respectively. The sampler 13 is used to collect the decarbonized solvent in the regeneration reactor 12, and the thermometer 15 is used to measure the temperature inside the regeneration reactor 12. A reflux condenser 14 is installed in the main port; its purpose is to condense and reflux the decarbonized solvent generated during the regeneration process. The reflux condenser includes a cooling medium outlet 20, a cooling medium inlet 19, and a CO2 gas outlet 18.

[0080] Example 1

[0081] Evaluation of solvents for decarbonization of ethanolamine

[0082] (1) A 30% w% N-methyldiethanolamine aqueous solution was used as the decarbonization solvent. 200 mL of the decarbonization solvent was injected into the absorption reactor 8, and the demister 7 was installed. The CO2-containing mixed gas storage tank 1 was opened, and the timing was started. The inlet gas flow meter 4 was adjusted to control the flow rate of the CO2-containing mixed gas to 150 mL / s. The inlet CO2 gas detector 3 showed that the CO2 content in the CO2-containing mixed gas was 14.0 v%. The CO2-containing mixed gas entered the bubble distributor 9 through pipeline I201, and after forming bubbles, it entered the interior of the absorption reactor 8. Inside the absorption reactor 8, the CO2-containing mixed gas and the decarbonization solvent reacted under the conditions of room temperature and gauge pressure of 10 kPa. After gas-liquid separation by the demister 7, it was discharged through pipeline II202. The pressure gauge 11 monitored that the pressure of the gas in pipeline I201 was stable at 10 kPa, indicating that the gas content ε in the gas-liquid mixture composed of the decarbonization solvent and the CO2-containing mixed gas was in a stable state. Specifically, the bubble distributor 9 has an aperture of 100 μm, and the CO2-containing gas mixture forms bubbles with a particle size of 100 μm after passing through the bubble distributor 9. 2 mL of the ethanolamine decarbonization solvent-rich solution is collected from the sampling port 10 at venting times of 1 min, 3 min, 5 min, and 10 min, respectively. When the outlet CO2 gas detector 5 shows a CO2 content of 13.6 v%, the reaction is stopped, and 2 mL of the ethanolamine decarbonization solvent-rich solution is collected. The outlet gas flow meter 6 displays the outlet gas flow rate. During the reaction, the gas source control valve 2 controls the opening and closing of the CO2-containing gas mixture storage tank 1.

[0083] (2) Back titration analysis of the CO2 absorption load of the ethanolamine decarbonization solvent-rich solution. The collected ethanolamine decarbonization solvent-rich solution was diluted 10 times with deionized water. A 0.01 mol / L Ca(OH)2 aqueous solution with calcium ion indicator was heated to 70°C. The diluted decarbonization solvent-rich solution was used to back titrate the Ca(OH)2 aqueous solution (red). When the red solution turned light blue and remained light blue for 3 minutes, the titration was stopped, and the titration volume was recorded. Calculate the CO2 absorption load of the solvent for the decarbonization of ethanolamine (see Table 1). Where V0 is 10 mL and c0 is 0.01 mol / L.

[0084] (3) Evaluation of decarbonization solvent regeneration performance. The rich solution of ethanolamine decarbonization solvent collected after 5 min of aeration in step (1) was injected into the regeneration reactor 12. The constant temperature heater 16 was turned on and heated to 90°C at thermometer 15. The temperature was controlled by the temperature control thermocouple 17 and kept constant for 5 min. Then, the sampler valve 13 was opened and 3 mL of the regenerated ethanolamine decarbonization solvent was measured. During the decarbonization solvent regeneration process, the regenerated CO2 was discharged from CO2 gas outlet 18, and the decarbonization solvent was condensed and refluxed through condenser reflux 14. In condenser reflux 14, the cooling medium entered condenser reflux 14 through cooling medium inlet 20 and was discharged from cooling medium outlet 19. The regenerated decarbonization solvent was directly titrated and analyzed according to the back titration method in step (2) to determine the residual CO2 load L without dilution. r , Repeat the above operation to analyze the residual CO2 load L of the ethanolamine decarbonization solvent at 100℃, 110℃, and 120℃. r (See Table 2). The specific cooling medium is water.

[0085] (4) According to the formula for calculating the CO2 absorption rate ν of the decarbonization solvent. Calculate the CO2 absorption rate ν of the decarbonization solvent for alkanolamines at different time periods; calculate the decarbonization solvent regeneration degree R according to the formula. The degree of regeneration R of the ethanolamine decarbonization solvent at different regeneration temperatures was calculated, as shown in Tables 1 and 2. The value of α is 3.6m. 2 The value of / L(α) is calculated based on a gas content ε of 6% and a bubble size of 100 μm. Specifically, the gas-liquid mixture per unit volume V 混 For a volume of 1 mL, with a bubble diameter of 100 μm and a radius of 50 μm, the volume V of each bubble is... q 5.2×10 -7 cm 3 The total volume V of bubbles in 1 mL of a gas-liquid mixture 气泡 =V 混 The gas content of the gas-liquid mixture ε = 1 × 6% = 0.06 mL, and the number of bubbles in the gas-liquid mixture n = V 气泡 / V q =0.06 / (5.2×10 -7 ) = 115385, the surface area of ​​each bubble S0 = 4πR 2 =3.14×10 -4 cm 2 The surface area of ​​all bubbles in the gas-liquid mixture is S = n × S0 = 115385 × 3.14 × 10⁻⁶. -4 =36cm 2 α = S / V 混 =36cm 2 / 1mL=3.6m 2 / L).

[0086] Table 1. Evaluation results of solvent absorption performance for ethanolamine decarbonization

[0087]

[0088] Table 2 Evaluation results of solvent regeneration performance for ethanolamine decarbonization

[0089]

[0090] Example 2

[0091] Evaluation of ionic liquid decarburization solvents

[0092] (1) 30 w% of 1-butyl-3-methylimidazolium hexafluorophosphate (ionic liquid) aqueous solution was used as the decarbonization solvent. 200 mL of the decarbonization solvent was injected into the absorption reactor 8 and the demister 7 was installed. The CO2 mixed gas storage tank 1 was opened and the timing was started. The inlet gas flow meter 4 was adjusted to control the flow rate of the CO2 mixed gas to 400 mL / s. The inlet CO2 gas detector 3 showed that the CO2 content in the CO2 mixed gas was 14.0 v%. The CO2 mixed gas entered the bubble distributor 9 through pipeline I201. After forming bubbles, it entered the inside of the absorption reactor 8. In the absorption reactor 8, the CO2 mixed gas and the decarbonization solvent reacted under the conditions of room temperature and gauge pressure 10 kPa. After gas-liquid separation by the demister 7, it was discharged through pipeline II202. The pressure gauge 11 monitored that the pressure of the gas in pipeline I201 was stable at gauge pressure 10 kPa, indicating that the gas content ε in the gas-liquid mixture composed of the decarbonization solvent and the CO2 mixed gas was in a stable state. Specifically, the bubble distributor 9 has an aperture of 100 μm, and the CO2-containing gas mixture forms bubbles with a particle size of 100 μm after passing through the bubble distributor 9. 2 mL of the ionic liquid decarbonization solvent-rich solution is collected from the sampling port 10 at 1 min, 3 min, 5 min, and 10 min of aeration time, respectively. When the CO2 content displayed by the outlet CO2 gas detector 5 reaches 13.6 v%, the reaction is stopped, and 2 mL of the ionic liquid decarbonization solvent-rich solution is collected. The outlet gas flow meter 6 displays the outlet gas flow rate. During the reaction, the opening and closing of the CO2-containing gas mixture storage tank 1 is controlled by the gas source control valve 2.

[0093] L, ν, and R were obtained using the same method as in Example 1, and the results are shown in Tables 3 and 4.

[0094] Table 3 Evaluation results of the decarbonization solvent absorption performance of ionic liquids

[0095]

[0096] Table 4 Evaluation Results of Regeneration Performance of Ionic Liquid Decarbonization Solvent

[0097]

[0098] Example 3

[0099] Evaluation of hindered amine decarbonization solvent

[0100] (1) A 30 wt% aqueous solution of 1,3-di(dimethylamino)-2-propanol (sterically hindered amine) was used as the decarbonization solvent. 200 mL of the decarbonization solvent was injected into the absorption reactor 8, and the demister 7 was installed. The CO2-containing gas storage tank 1 was opened, and the timing was started. The inlet gas flow meter 4 was adjusted to control the flow rate of the CO2-containing gas mixture to 380 mL / s. The inlet CO2 gas detector 3 showed that the CO2 content in the CO2-containing gas mixture was 14.0 wt%. The CO2-containing gas mixture entered the bubble distributor 9 through pipeline I201, and after forming bubbles, it entered the interior of the absorption reactor 8. Inside the absorption reactor 8, the CO2-containing gas mixture and the decarbonization solvent reacted under the conditions of room temperature and gauge pressure 20 kPa. After gas-liquid separation by the demister 7, the mixture was discharged through pipeline II202. The pressure gauge 11 monitored that the pressure of the gas in pipeline I201 was stable at 20 kPa, indicating that the gas content ε in the gas-liquid mixture composed of the decarbonization solvent and the CO2-containing gas mixture was in a stable state. Specifically, the bubble distributor 9 has an aperture of 100 μm, and the CO2-containing gas mixture forms bubbles with a particle size of 100 μm after passing through the bubble distributor 9. 2 mL of the hindered amine decarbonization solvent-rich solution is collected from the sampling port 10 at 1 min, 3 min, 5 min, and 10 min of aeration time, respectively. When the CO2 content displayed by the outlet CO2 gas detector 5 reaches 13.6 v%, the reaction is stopped, and 2 mL of the hindered amine decarbonization solvent-rich solution is collected. The outlet gas flow meter 6 displays the outlet gas flow rate. During the reaction, the opening and closing of the CO2-containing gas mixture storage tank 1 is controlled by the gas source control valve 2.

[0101] L, ν, and R were obtained using the same method as in Example 1, and the results are shown in Tables 5 and 6.

[0102] Table 5. Evaluation Results of Solvent Absorption Performance for Amine Decarbonization

[0103]

[0104] Table 6. Evaluation Results of Solvent Regeneration Performance for Amine Decarbonization

[0105]

[0106] Example 4

[0107] Evaluation of amino acid salt decarbonization solvents

[0108] A 30% wt% sodium glycinate (amino acid salt) aqueous solution was used as the decarbonization solvent. 200 mL of the decarbonization solvent was injected into the absorption reactor 8, and the demister 7 was installed. The CO2-containing gas storage tank 1 was opened, and timing was started. The inlet gas flow meter 4 was adjusted to control the CO2-containing gas flow rate to 650 mL / s. The inlet CO2 gas detector 3 showed that the CO2 content in the CO2-containing gas mixture was 14.0 wt%. The CO2-containing gas mixture entered the bubble distributor 9 through pipeline I201, formed bubbles, and then entered the absorption reactor 8. Inside the absorption reactor 8, the CO2-containing gas mixture and the decarbonization solvent reacted at room temperature and a gauge pressure of 100 kPa. After gas-liquid separation by the demister 7, the mixture was discharged through pipeline II202. The pressure gauge 11 monitored the gas pressure in pipeline I201, which remained stable at 100 kPa, indicating that the gas content ε in the gas-liquid mixture composed of the decarbonization solvent and the CO2-containing gas mixture was in a stable state. Specifically, the bubble distributor 9 has an aperture of 100 μm, and the CO2-containing mixed gas forms bubbles with a particle size of 100 μm after passing through the bubble distributor 9. 2 mL of the amino acid salt decarbonization solvent-rich solution is collected from the sampling port 10 at 1 min, 3 min, 5 min, and 10 min of venting time. When the CO2 content displayed by the outlet CO2 gas detector 5 reaches 13.6 v%, the reaction is stopped, and 2 mL of the amino acid salt decarbonization solvent-rich solution is collected. The outlet gas flow meter 6 displays the outlet gas flow rate. During the reaction, the opening and closing of the CO2-containing mixed gas storage tank 1 is controlled by the gas source control valve 2.

[0109] L, ν, and R were obtained using the same method as in Example 1, and the results are shown in Tables 7 and 8.

[0110] Table 7 Evaluation results of amino acid salt decarbonization solvent absorption performance

[0111]

[0112] Table 8 Evaluation Results of Regeneration Performance of Amino Acid Salt Decarbonization Solvent

[0113]

[0114] As can be seen from the above embodiments, the evaluation method for decarbonization solvents provided in this invention can be applied to a variety of decarbonization solvents. Using the decarbonization solvent evaluation method provided by this invention, those skilled in the art can evaluate the decarbonization solvent under the same evaluation conditions by the CO2 load L in the decarbonization solvent, the CO2 absorption rate ν of the decarbonization solvent, and the regeneration degree R.

[0115] Verification of the repeatability of the evaluation method:

[0116] Take 1000 mL of a 30% N-methyldiethanolamine aqueous solution and divide it into five equal portions of 200 mL each. Verify the repeatability of the evaluation method according to the evaluation steps in Example 1. The reaction time is 5 min and the regeneration temperature is 120 °C. The CO2 absorption load L of the 30% N-methyldiethanolamine aqueous solution decarbonization solvent and the residual CO2 load L in the regenerated decarbonization solvent are obtained, respectively. r The results are shown in Tables 9 and 10.

[0117] Table 9. Repeatability verification results of CO2 absorption load L of decarbonization solvent in the evaluation method.

[0118]

[0119] Table 10 Evaluation methods for L after decarbonization solvent regeneration r Repeatability verification results

[0120]

[0121] As shown in Tables 9 and 10, the decarbonization solvent evaluation method provided in this invention, in terms of evaluating the CO2 load index of the decarbonization solvent, L and L r The relative standard deviation (RSD) is less than 3.00%, indicating good repeatability.

[0122] Validation of the accuracy of the evaluation method

[0123] According to the 2012 issue of *Journal of Chemical Industry and Engineering (China)*, in the paper "Synthesis, Characterization and CO2 Absorption Performance of Functional Ionic Liquids" published by the State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, "The saturated absorption capacity of the amine-functional ionic liquid 1-(1-aminopropyl)-3-methylimidazolium bromide is 0.63 mol CO2 / mol [NH2P]". mim When a 30 wt% aqueous solution of 1-(1-aminopropyl)-3-methylimidazolium bromide is used as the decarbonization solvent, its theoretical CO2 saturation absorption capacity is 0.8591 mol / L. The CO2 absorption load of the 30 wt% aqueous solution of 1-(1-aminopropyl)-3-methylimidazolium bromide was evaluated using the decarbonization solvent evaluation method of this invention, and the results are shown in Table 11.

[0124] Table 11 Evaluation Results of Decarbonization Solvent Absorption Performance of 1-(1-aminopropyl)-3-methylimidazolium bromide

[0125]

[0126] As shown in Table 11, the CO2 saturation absorption load of the 30w% aqueous solution of 1-(1-aminopropyl)-3-methylimidazolium bromide obtained by the technical method of the present invention is 0.86 mol / L, which is close to the theoretical value.

[0127] Comparative Example

[0128] N-methyldiethanolamine was evaluated according to the purification performance evaluation method for amine desulfurization / decarbonization agents provided in GB / T 36767—2018. 10 L of a 30% N-methyldiethanolamine aqueous solution was prepared as the decarbonization solvent. The same simulated flue gas as in Example 1 was used as the gas source, and the decarbonization solvent was evaluated according to the evaluation conditions in Table-12.

[0129] Table 12 Evaluation Criteria of GB / T 36767—2018

[0130] Evaluation criteria numerical values Decarbonization solvent circulation volume 5.0L / h Gas flow rate <![CDATA[1.0Nm 3 / h]]> Absorbing pressure 8.0MPa Regeneration pressure 0.1MPa Regeneration temperature 120℃

[0131] After the evaluation system stabilized for 2 hours, the CO2 content in the outlet gas of the absorption tower was analyzed. Gas chromatography (GDX-104) was used to measure the CO2 volume fraction every 1 hour, and the three consecutive CO2 volume fractions were 7.8%, 8.6%, and 7.9%, respectively. It is known that the evaluation method for the purification performance of amine decarbonizing agents provided in GB / T36767—2018, which evaluates decarbonizing solvents, consumes 10 L, takes 5 hours, and has an RSD of 5.38%. According to the decarbonizing solvent evaluation method of this invention, evaluating a decarbonizing solvent in this invention consumes 200 mL, takes less than 150 minutes, and has a relative error of less than 3.00%. Based on the above comparison, it can be seen that the evaluation method of this invention consumes less solvent, takes less time, and has a smaller relative error.

[0132] In summary, the evaluation method provided by this invention includes L, ν, and R as evaluation parameters. The evaluation results are intuitive, accurate, have small errors, and are highly repeatable. It can evaluate various types of decarbonization solvents, and the consumption of decarbonization solvent is low and the time required is short.

[0133] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for evaluating decarbonization solvents, characterized in that, The evaluation method includes the following steps: (1) A CO2-containing mixed gas reacts with a decarbonization solvent to obtain a decarbonization solvent-rich solution. When the reaction time is t, the decarbonization solvent-rich solution is collected and the CO2 load in the decarbonization solvent-rich solution is measured and recorded as L. When the decarbonization solvent absorbs CO2 to the saturation state, the reaction is stopped. (2) The decarbonization solvent rich solution collected in step (1) is subjected to a regeneration reaction. The regenerated decarbonization solvent is collected, and the load of residual CO2 in the regenerated decarbonization solvent is measured and recorded as Lr. (3) Calculate the decarbonization solvent regeneration degree R. The decarbonization solvent is evaluated by the CO2 load L in the decarbonization solvent-rich solution and the decarbonization solvent regeneration degree R.

2. The evaluation method according to claim 1, characterized in that, In step (1), the CO2-containing mixed gas passes through the decarbonization solvent in the form of bubbles, forming a mixture of CO2-containing mixed gas and decarbonization solvent, denoted as a gas-liquid mixture. When the gas content ε of the gas-liquid mixture is stable, the volume of the gas-liquid mixture per unit volume is denoted as V. 混 Calculate V 混 The surface area of ​​all the bubbles in the middle is denoted as S, and S / V 混 Let α be the value of CO2 absorption by the decarbonization solvent. The decarbonization solvent is evaluated by the rate ν.

3. The evaluation method according to claim 2, characterized in that, In step (1), with a volume of 200 mL of decarbonization solvent, the flow rate of the CO2-containing mixed gas is 50-1000 mL / s; preferably 150-650 mL / s. And / or, in step (1), the diameter of the bubble is 50 to 150 μm; preferably 90 to 110 μm.

4. The evaluation method according to any one of claims 1 to 3, characterized in that, L was measured using reverse titration. Preferably, the L is measured by back titration with a standard Ca(OH)2 aqueous solution. Where V0 is the volume of the standard Ca(OH)2 aqueous solution; c0 is the concentration of the standard Ca(OH)2 aqueous solution; V1 is the titration volume of the decarbonization solvent-rich solution collected at reaction time t; And / or, L is measured by back titration. r ; Preferably, L is measured by back titration with a standard Ca(OH)2 aqueous solution. r , Where V0 is the volume of the standard Ca(OH)2 aqueous solution; c0 is the concentration of a standard Ca(OH)2 aqueous solution; V 1r This is the titration volume of the regenerated decarbonized solvent.

5. The evaluation method according to any one of claims 1 to 4, characterized in that, The conditions for the reaction of the CO2-containing mixed gas with the decarbonization solvent include: a pressure of 5-100 kPa gauge pressure and a temperature of 20-30°C. Preferably, the pressure is 10–20 kPa (gauge pressure); And / or, the conditions for the regeneration reaction include: a temperature of 90–120°C and a time of 5–10 min; And / or, the CO2 content in the CO2-containing gas mixture is 10v% to 30v%.

6. The evaluation method according to any one of claims 1 to 5, characterized in that, The decarbonization solvent is selected from one or more of alkanolamines, ionic liquids, amino acid salts, and sterically hindered amines; Preferably, the alcohol amine is selected from one or more of primary alcohol amines, secondary alcohol amines, tertiary alcohol amines and their derivatives; And / or, the ionic liquid is selected from one or more of imidazolium ionic liquids, pyridinium ionic liquids, quaternary ammonium salt ionic liquids, piperidine ionic liquids and pyrrolidine ionic liquids; And / or, the amino acid salt is selected from one or more alkali metal salts of amino acids; Further preferred are one or more of sodium glycinate, potassium glycinate, sodium alanine, potassium alanine, sodium lysine, and potassium lysine; And / or, the hindered amine is selected from one or more of 2-amino-2-methyl-1-propanol, tert-butylaminoethoxyethanol, and 1,3-di(dimethylamino)-2-propanol.

7. The evaluation method according to any one of claims 1 to 6, characterized in that, In step (1), the reaction time t is greater than or equal to 1 min; the reaction time t is less than or equal to the time required for the decarbonization solvent to become saturated.

8. The evaluation method according to any one of claims 1 to 7, characterized in that, L includes: the amount of free CO2 in the decarbonization solvent-rich solution and the amount of CO2 that participates in the reaction; And / or, L r This includes the amount of residual free CO2 in the regenerated decarbonization solvent and the amount of CO2 that participates in the reaction.

9. An evaluation apparatus used in the evaluation method according to any one of claims 1 to 8, characterized in that, The evaluation device includes: a decarbonization solvent CO2 absorption device and a decarbonization solvent regeneration device. The decarbonization solvent CO2 absorption device includes: a CO2-containing mixed gas storage tank, a gas source control valve, an inlet CO2 gas detector, an inlet gas flow meter, a pressure gauge, an absorption reactor, an outlet CO2 gas detector, and an outlet gas flow meter; the CO2-containing mixed gas storage tank is connected to the inlet of the absorption reactor via pipeline I, and the gas source control valve, the inlet CO2 gas detector, the inlet gas flow meter, and the pressure gauge are installed on pipeline I; the gas in the absorption reactor is discharged through pipeline II, and the outlet CO2 gas detector and the outlet gas flow meter are installed on pipeline II; The absorption reactor is equipped with a bubble distributor at the air inlet, a demister at the air outlet, and a decarbonization solvent sampling port. The CO2 decarbonization solvent regeneration device includes a regeneration reactor, a temperature control device, and a sampler; the regeneration reactor is used to carry out the regeneration reaction of the decarbonization solvent, the temperature control device is used to control the temperature of the regeneration reactor, and the sampler is used to collect the decarbonization solvent in the regeneration reactor.

10. The evaluation device according to claim 9, characterized in that, The pore size of the bubble distributor is 50–150 μm; preferably 90–110 μm.

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