Method for detecting organic amine in carbon dioxide capture waste liquid

Abstract

The invention relates to a method for detecting organic amine in carbon dioxide capture waste liquid, which comprises the following steps: the organic amine in the carbon dioxide capture waste liquid is detected by gas chromatography-mass spectrometry, and a to-be-detected solution for sample injection comprises a to-be-detected solution formed by methanol as a solvent and the to-be-detected organic amine. The sample introduction is split sample introduction, and the sample introduction ratio of the organic amine to be detected in the split sample introduction is 100: 1. The result obtained by the invention can be used in actual production practice to assist the achievement of the dual-carbon target.

Description

Technical Field

[0001] The invention relates to the technical field of analysis and detection, and in particular to a method for detecting organic amines in carbon dioxide capture waste liquid. Background Art

[0002] Among the existing CCUS technologies (Carbon Capture, Utilization, and Storage, CCUS for short, which is a technology that can effectively capture and utilize carbon dioxide, it can capture and seal carbon dioxide emitted during the production process, or purify it and put it into a new production process for recycling), chemical solvent absorption method is currently a method widely used in the industry for post-combustion CO2 capture due to its high absorption efficiency and large processing capacity. Alcoholamine compounds mainly react with CO2 to form carbamates and carbonates to achieve CO2 capture. They are low-cost and easy to recycle, and are widely used in CO2 capture in industrial processes such as cement manufacturing, steel production, and fossil fuel power plants. The most widely studied amines are: primary amines represented by monoethanolamine (MEA), secondary amines represented by 2-methylethanolamine (MMEA), and sterically hindered amines represented by 2-amino-2-methyl-1-propanol (AMP).

[0003] In actual industrial applications, oxygen (O2), sulfur oxides (SOx), nitrogen oxides (NOx) and other substances in flue gas can easily lead to the degradation of alcohol amines by different mechanisms, and some of the degradation products are toxic and polluting, which pose potential dangers to humans or the environment. In addition, alcohol amine degradation can also cause solvent loss, reduced CO2 capture efficiency, scaling, foaming, corrosion, increased viscosity and other problems, resulting in increased industrial costs, increased process difficulty and increased reaction energy consumption. The content and composition of alcohol amine compounds directly affect the CO2 absorption efficiency of the carbon capture process.

[0004] Since flue gas often contains impurities such as smoke, H2O, O2, SOx, etc. that can poison the amine solution, and the absorption tower of the capture system usually operates at a higher temperature, the alcohol amine solution undergoes an irreversible chemical reaction with the impurity molecules in the flue gas during the capture of carbon dioxide, and the process of generating stable substances is called the degradation of the absorbent. The degradation of the absorbent will cause the loss of the absorbent and the degradation of the ability to absorb CO2, resulting in the need to replenish the system with new absorbents from time to time, increasing the operating cost; at the same time, the degradation products will cause a series of phenomena such as equipment corrosion and solution foaming, reducing the life of the system, and volatile degradation products will also cause environmental pollution. Therefore, the identification of the composition information of the circulating liquid of alcohol amine absorbents in carbon dioxide capture agents has important guiding significance for the recycling of alcohol amine absorption.

[0005] At present, the detection methods of alcoholamine compounds mainly include gas chromatography, gas chromatography-mass spectrometry, high performance liquid chromatography, liquid chromatography-mass spectrometry, ion chromatography, etc., but the above methods all have advantages and disadvantages. Chromatographic instruments (such as gas chromatography, liquid chromatography and ion chromatography) can only be qualitatively determined by retention time, cannot provide structural fragment information, and cannot analyze complex components. Alcoholamine absorbents may undergo oxidative degradation, thermal degradation and other processes during absorption and high-temperature distillation. In addition to alcoholamine absorbents, there may be a variety of unknown degradation products in the circulating liquid components. Therefore, chromatography-mass spectrometry technology is a possible solution. Studies have reported that liquid chromatography-mass spectrometry is used for the detection of alcoholamine substances, but due to the active nature of these compounds (especially ethanolamine), they may react with the mobile phase, and the results obtained have certain false positives. Gas chromatography-mass spectrometry is used for the detection of such substances because of its strong separation ability and the use of inert gas as carrier gas. However, due to the strong adsorption of polar hydroxyl and amine groups on chromatographic columns in the structure of alcoholamine compounds, chromatographic peak tailing often occurs, especially the most commonly used MEA tailing is the most serious. In addition, since alcoholamines, especially small molecule MEA, are extremely active, they can react with common gas chromatography injection solvents (such as ethyl acetate, dichloromethane, acetone, etc.). Therefore, the precise analysis of the components of alcoholamine absorbents in carbon dioxide capture agents has important application value for their recycling, production increase and efficiency improvement. Summary of the invention

[0006] The main purpose of the present invention is to overcome the defects in the existing detection of organic amines in carbon dioxide capture waste liquid and provide a new method for detecting organic amines in carbon dioxide capture waste liquid. The technical problem to be solved is to enable it to detect mixed organic amines with multiple amines and to perform accurate analysis. It has important application value for the recycling, increase in production and improvement in efficiency of organic amines, and is therefore more suitable for practical use and has industrial utilization value.

[0007] The purpose of the present invention and the solution to the technical problem are achieved by adopting the following technical solutions.

[0008] The present invention provides a method for detecting organic amines in carbon dioxide capture waste liquid, the method comprising:

[0009] The organic amines in the carbon dioxide capture waste liquid are detected by gas chromatography-mass spectrometry, and the sampling is split-flow sampling, wherein the sampling ratio of the organic amine to be detected in the split-flow sampling is 100:1.

[0010] In an optional embodiment, the method further comprises: maintaining the initial temperature of the chromatographic column in the gas chromatograph at 30° C.-35° C. for a first preset time;

[0011] The temperature of the chromatographic column is raised to a first preset temperature at a heating rate of 15 ml / min, and then raised to a second preset temperature at a heating rate of 10°C / min, and maintained for 3-5 minutes; wherein the second preset temperature is twice the first preset temperature;

[0012] The sample is injected through the injection port of the chromatographic column, and the injection temperature is a third preset temperature, and the third preset temperature is between the first preset temperature and the second preset temperature.

[0013] In an optional embodiment, the organic amines in the organic amines to be detected include at least one of ethanolamine (MEA), N-methylethanolamine (MMEA) and 2-amino-2-methyl-1-propanol (AMP).

[0014] In an optional embodiment, the filler of the chromatographic column is cyanopropyl / phenyl and polydimethylsiloxane;

[0015] The proportion of cyanopropyl / phenyl is 6%, and the proportion of polydimethylsiloxane is 94%.

[0016] In an optional embodiment, the chromatographic column is a polar chromatographic column.

[0017] In an optional embodiment, the first preset temperature is 120°C-140°C.

[0018] In an optional embodiment, the second preset temperature is 240°C-280°C.

[0019] In an optional embodiment, the third preset temperature is 180°C-230°C.

[0020] In an optional embodiment, the mass spectrometry conditions of the gas chromatography-mass spectrometry method include: a transmission line temperature of 280°C; and an ion source temperature of 300°C.

[0021] In an optional embodiment, the first preset time is 3-5 minutes, and the second preset time is 3-5 minutes.

[0022] By means of the above technical solution, the present invention (name) has at least the following advantages:

[0023] The method for detecting organic amines in carbon dioxide capture waste liquid of the embodiment of the present invention is based on the use of methanol as the injection solvent, that is, dissolving the organic amine to be detected by methanol. Since methanol has a large expansion coefficient, it is rarely used in gas chromatography injection. This study uses methanol as a solvent, which can detect mixed organic amines with multiple amines, and can perform precise analysis, which has important application value for the recycling, increase in production and efficiency of organic amines. The method provided by the embodiment of the present invention is practical and reliable, avoids the inertial thinking in chromatographic detection, and explains the experimental phenomena from the perspective of organic reactions. The results obtained can be used in actual production practice to help achieve the dual carbon goals.

[0024] In summary, the special method for detecting organic amines in carbon dioxide capture waste liquid of the present invention uses methanol as a solvent, can detect mixed organic amines with multiple amines, and can perform accurate analysis, which has important application value for the recycling, production increase and efficiency improvement of organic amines. It has many of the above advantages and practical value, and no similar design has been published or used in similar methods, so it is indeed innovative. It has great improvements in both method and function, great progress in technology, and produces good and practical effects. It has multiple enhanced functions compared with the existing method for detecting organic amines in carbon dioxide capture waste liquid, so it is more suitable for practical use and has wide industrial utilization value. It is truly a novel, progressive and practical new design.

[0025] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings.

[0026] The specific method for detecting organic amines in carbon dioxide capture waste liquid of the present invention is described in detail in the following examples and their accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of characteristic fragment ions of MEA provided in an embodiment of the present invention.

[0028] Figure 2 Chromatograms of three organic amines with by-products provided in the embodiments of the present invention.

[0029] Figure 3 A schematic diagram of a possible generation mechanism of MEA by-products provided in an embodiment of the present invention.

[0030] Figure 4 The optimized TIC diagrams of three organic amines provided in the embodiments of the present invention.

[0031] Figure 5 This is a TIC diagram of waste liquid after distillation from a power plant provided in accordance with an embodiment of the present invention.

[0032] Figure 6 This is an enlarged TIC diagram of the 18-22 min degradation product provided in an embodiment of the present invention.

[0033] Figure 7 The possible molecular structural formula of the main degradation product provided in the embodiments of the present invention.

[0034] Figure 8 Schematic diagram of possible generation mechanism of MEA by-products according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation method of the method for detecting organic amines in carbon dioxide capture waste liquid proposed by the present invention is described in detail below in combination with the accompanying drawings and preferred embodiments.

[0036] The method for detecting organic amines in carbon dioxide capture waste liquid of a preferred embodiment of the present invention mainly comprises the following steps: detecting organic amines in carbon dioxide capture waste liquid by gas chromatography-mass spectrometry, wherein the initial temperature of the chromatographic column in the gas chromatography is maintained at 30°C-35°C for a first preset time.

[0037] The temperature of the chromatographic column is raised to a first preset temperature at a heating rate of 15 ml / min, and then raised to a second preset temperature at a heating rate of 10°C / min, and maintained for 3-5 minutes; wherein the second preset temperature is twice the first preset temperature.

[0038] The sample is injected through the injection port of the chromatographic column, and the injection temperature is a third preset temperature, and the third preset temperature is between the first preset temperature and the second preset temperature.

[0039] The injected solution to be detected includes a solution to be detected formed by using methanol as a solvent and the organic amine to be detected.

[0040] The sampling of the present invention is split-flow sampling, wherein the sampling ratio of the organic amine to be detected in the split-flow sampling is 100:1.

[0041] The method for detecting organic amines in carbon dioxide capture waste liquid of the embodiment of the present invention is based on the use of methanol as the injection solvent, that is, dissolving the organic amine to be detected by methanol. Since methanol has a large expansion coefficient, it is rarely used in gas chromatography injection. This study uses methanol as a solvent, which can detect mixed organic amines with multiple amines, and can perform precise analysis, which has important application value for the recycling, increase in production and efficiency of organic amines. The method provided by the embodiment of the present invention is practical and reliable, avoids the inertial thinking in chromatographic detection, and explains the experimental phenomena from the perspective of organic reactions. The results obtained can be used in actual production practice to help achieve the dual carbon goals.

[0042] In an optional embodiment, the organic amines in the organic amines to be detected include at least one of ethanolamine (MEA), N-methylethanolamine (MMEA) and 2-amino-2-methyl-1-propanol (AMP).

[0043] The type of organic amine in the solution to be detected analyzed by the embodiment of the present invention can be a mixture of the above-mentioned ethanolamine (MEA) and N-methylethanolamine (MMEA), or a mixture of N-methylethanolamine (MMEA) and 2-amino-2-methyl-1-propanol (AMP), or a mixture of ethanolamine (MEA), N-methylethanolamine (MMEA) and 2-amino-2-methyl-1-propanol (AMP). That is, the embodiment of the present invention can analyze a mixture of two to three of the above-mentioned organic amines, and the analysis result is accurate.

[0044] In an optional embodiment, the fillers of the chromatographic column are cyanopropyl / phenyl and polydimethylsiloxane, wherein the proportion of cyanopropyl / phenyl is 6% and the proportion of polydimethylsiloxane is 94%.

[0045] In an optional embodiment, the chromatographic column is a polar chromatographic column.

[0046] For example, the polar chromatographic column may be a chromatographic column of model DB-624. The model of the chromatographic column in the embodiment of the present invention is not limited thereto.

[0047] In an optional embodiment, the first preset temperature is 120° C.-140° C. Exemplarily, the first preset temperature is 120° C., 123° C., 124° C., 126° C., 127° C., 130° C., 131° C., 132° C., 136° C., 137° C., 138° C., 139° C. or 140° C., etc.

[0048] In an optional embodiment, the second preset temperature is 240° C.-280° C. For example, the first preset temperature is 240° C., 243° C., 244° C., 246° C., 247° C., 250° C., 25° C., 252° C., 266° C., 267° C., 278° C., 279° C. or 280° C.

[0049] In an optional embodiment, the third preset temperature is 180° C.-230° C. Exemplarily, the first preset temperature is 180° C., 183° C., 184° C., 186° C., 187° C., 190° C., 191° C., 202° C., 216° C., 217° C., 228° C., 229° C. or 230° C., etc.

[0050] The injection provided by the present invention is split injection, wherein the injection ratio of the organic amine to be detected to helium or air in the split injection is 100:1. Figure 4 , the split ratio used in the embodiment of the present invention is 1:100. The multiple amines in the organic amines to be detected are effectively separated without interference, and the average recoveries of MEA, MMEA and APM are 105%, 101% and 95%, respectively, and the relative standard deviations are 0.8% to 4.1%, respectively. Under the determined chromatographic conditions, the mixed standard solution (organic amines to be detected) series prepared by drawing the standard curve in Example 1 is used for injection measurement, and the peak areas of MEA, MMEA and AMP of different concentrations are measured, and the linear regression equation standard curve is drawn. The r values ​​of the five alcoholamine compounds are all greater than 0.999.

[0051] In an optional embodiment, the mass spectrometry conditions of the gas chromatography-mass spectrometry method include: a transfer line temperature of 280°C; and an ion source temperature of 300°C.

[0052] In an optional embodiment, the first preset time is 3-5 minutes, and the second preset time is 3-5 minutes. Exemplarily, the first preset time can be 3 minutes, 4 minutes or 5 minutes, and the second preset time can be 3 minutes, 4 minutes or 5 minutes.

[0053] The method provided by the present invention will be explained and illustrated by further examples below.

[0054] Example 1

[0055] The invention provides a method for detecting organic amines in carbon dioxide capture waste liquid. The adopted instruments include: a gas chromatograph-mass spectrometer, an SB-50OD ultrasonic cleaning machine; a 10uL pipette; a 20-200uL pipette; and a 10uL 1700 series N-type microinjection needle.

[0056] Drugs and reagents: ethanolamine (C2H7NO, AR, 99%), N-methyl-2-hydroxyethylamine (C3H9NO, 95%) and 2-amino-2-methyl-1-propanol (C4H 11 NO, 98%). Methanol, ethyl acetate, acetone and dichloromethane were all of chromatographic grade.

[0057] Materials: DB-624 column (0.5 g / 6 mL, 60 m), 6% cyanopropyl / phenyl, 94% polydimethylsiloxane.

[0058] Chromatographic conditions: initially 30°C, hold for 1 min, increase to 120°C at a heating rate of 15 ml / min, then increase to 240°C at a heating rate of 10°C / min, and hold for 3 minutes; Inlet: temperature is 220°C, split mode is adopted, split flow rate is 15 ml / min, split ratio is 100, air flow rate is 15 mL / min, and helium flow rate is 1.5 mL / min.

[0059] The mass spectrometry conditions included: transfer line temperature: 280°C; ion source temperature: 300°C; qualitative scan: SCAN mode, data acquisition time starting from 9.5 min, dwell time of 0.2 s; acquisition range: 25-300.

[0060] Example 2

[0061] Selection of mass range: In gas chromatography mass spectrometry, the instrument defaults to m / z starting from 50, while the main characteristic fragment of the gas chromatography mass spectrometry in the method provided in the embodiment of the present invention is 30 (e.g. Figure 1 Therefore, the mass range was selected as m / z (mass-to-charge ratio) 25-300.

[0062] Selection of chromatographic columns and packing materials

[0063] A common DB-5 chromatographic column and a highly polar DB-5 DB-624 chromatographic column were selected for comparative experiments. A certain amount of standard solution was added to the blank and sample by the spike recovery method, and the sample was measured according to Example 1. Figure 3 It can be seen that the average recovery rates of ethanolamine, N-methyl-2-hydroxyethylamine and 2-amino-2-methyl-1-propanol in the chromatographic column with model DB-624 are 105%, 101% and 82% respectively, all between 70% and 130%, and the relative standard deviations are 0.8% to 3.1% respectively. However, the conventional filler is a chromatographic column such as DB-5 with (5% phenyl) methyl polysiloxane, because the small molecule amine in the embodiment of the present invention has a strong polarity, it cannot be effectively separated in the chromatographic column, only AMP is separated at 4.27min, and the peak shape is severely tailed, which is not conducive to quantitative analysis. Therefore, the chromatographic column with polar model DB-624 is the most conducive to the solid phase extraction purification experiment of organic alcohol amine compounds.

[0064] Choice of organic solvent

[0065] Related technologies select ethyl acetate and dichloromethane as common gas chromatography injection solvents. However, small molecule organic amines can undergo nucleophilic substitution reactions with dichloromethane, while ester aminolysis reactions will occur with ethyl acetate. Taking into account the small molecule organic amines and their compatibility with the gas chromatography injection port, acetone with medium polarity is selected as the injection solvent.

[0066] Depend on Figure 2 It can be seen that the three target small molecule organic amines were effectively separated, but two impurity peaks appeared at the same time. The searched structures were MEA and MMEA react with the carbonyl group of acetone in a condensation reaction. The mechanism is as follows: Figure 3 shown.

[0067] The conversion rate of MEA is higher and much higher than that of MMEA, while AMP is not converted due to steric hindrance. Therefore, the use of acetone as a solvent affects the qualitative and quantitative analysis of MEA and MMEA, especially MEA.

[0068] The embodiment of the present invention uses methanol as the solvent and uses a split ratio of 100:1. This allows multiple amines to be separated effectively and without interference (e.g. Figure 4 and 5 The average recoveries of MEA, MMEA and APM were 105%, 101% and 95%, respectively, and the relative standard deviations were 0.8% to 4.1%, respectively. Under the determined chromatographic conditions, the mixed standard solution series prepared by drawing the standard curve in Example 1 was used for injection measurement, the peak areas of MEA, MMEA and AMP at different concentrations were measured, and the linear regression equation standard curve was drawn. The r values ​​of the five alcoholamine compounds were all greater than 0.999.

[0069] Example 3

[0070] According to the above method, the decarbonization waste liquid after distillation recovery of a power plant was analyzed, and the content of three alcohol amine CO2 absorbents (MEA, MMEA and AMP) in the waste liquid was determined. Figure 6 As shown in Figure 2, the contents of MEA, MMEA and APMA are approximately 5.54%, 5.51% and 10.1% respectively. Combining the NIST spectral library search and possible chemical reactions, the main degradation product structures were deduced (e.g. Figure 7 ) and some generated paths (such as Figure 8 ). According to the chromatographic separation results, the boiling points of the three raw materials and the degradation products are quite different. It is suggested that the distillation recovery efficiency can be further improved to reduce the generation of degradation products.

[0071] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes by using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for detecting organic amines in carbon dioxide capture waste liquid, characterized in that: The method comprises: The organic amines in the carbon dioxide capture waste liquid are detected by gas chromatography-mass spectrometry. The injected solution to be detected includes a solution to be detected formed by using methanol as a solvent and the organic amine to be detected. The injection is split injection, wherein the injection ratio of the organic amine to be detected in the split injection is 100:

1.

2. The method for detecting organic amines in carbon dioxide capture waste liquid according to claim 1, characterized in that: Also includes: Maintaining the initial temperature of the chromatographic column in the gas chromatograph at 30°C-35°C for a first preset time; The temperature of the chromatographic column is raised to a first preset temperature at a heating rate of 15 ml / min, and then raised to a second preset temperature at a heating rate of 10°C / min, and maintained for 3-5 minutes; wherein the second preset temperature is twice the first preset temperature; The sample is injected through the injection port of the chromatographic column, and the injection temperature is a third preset temperature, and the third preset temperature is between the first preset temperature and the second preset temperature.

3. The method for detecting organic amines in carbon dioxide capture waste liquid according to claim 1, characterized in that: The organic amines to be detected include at least one of ethanolamine (MEA), N-methylethanolamine (MMEA) and 2-amino-2-methyl-1-propanol (AMP).

4. The method for detecting organic amines in carbon dioxide capture waste liquid according to claim 1, characterized in that: The fillers of the chromatographic column are cyanopropyl / phenyl and polydimethylsiloxane; The proportion of cyanopropyl / phenyl is 6%, and the proportion of polydimethylsiloxane is 94%.

5. The method for detecting organic amines in carbon dioxide capture waste liquid according to claim 1, characterized in that: The chromatographic column is a polar chromatographic column.

6. The method for detecting organic amines in carbon dioxide capture waste liquid according to claim 1, characterized in that: The first preset temperature is 120°C-140°C.

7. The method for detecting organic amines in carbon dioxide capture waste liquid according to claim 1, characterized in that: The second preset temperature is 240°C-280°C.

8. The method for detecting organic amines in carbon dioxide capture waste liquid according to claim 1, characterized in that: The third preset temperature is 180°C-230°C.

9. The method for detecting organic amines in carbon dioxide capture waste liquid according to claim 8, characterized in that: The mass spectrometry conditions of the gas chromatography-mass spectrometry method include: a transmission line temperature of 280° C.; and an ion source temperature of 300° C.

10. The method for detecting organic amines in carbon dioxide capture waste liquid according to claim 9, characterized in that: The first preset time is 3-5 minutes, and the second preset time is 3-5 minutes.

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