CO2 absorbent high-throughput screening device and method based on optical reflection imaging

Abstract

The invention provides a CO2 absorbent high-throughput screening device based on optical reflection imaging, and belongs to the technical field of flue gas decarburization, the CO2 absorbent high-throughput screening device comprises a perforated plate, an imaging system and a gas injection unit; the imaging system comprises a sample table for bearing a perforated plate, a light source, a light beam collimating and expanding system, a light beam shrinking system and a CCD (Charge Coupled Device) camera; the light source irradiates the bottom of the sample hole through the light beam collimating and expanding system; the CCD camera receives and collects an optical intensity signal reflected by the sample in the sample hole through the light beam shrinking system; the gas injection unit comprises a gas source and a multi-channel gas pipeline. By utilizing the spatial resolution of optical imaging, 96-well plates and even more samples can be measured at the same time, and the screening efficiency is greatly improved. The invention further relates to a CO2 absorbent high-throughput screening method based on optical reflection imaging.

Description

Technical Field

[0001] This invention relates to the field of flue gas decarbonization technology, and more specifically, to a high-throughput screening device for CO2 absorbents based on optical reflection imaging. This invention also relates to a high-throughput screening method for CO2 absorbents based on optical reflection imaging. Background Technology

[0002] With the global energy structure transformation, coal-fired power plants, as the main energy supplier, have become a key target for carbon capture, with 10%-20% of their CO2 emissions from flue gas becoming part of the energy supply. Aqueous solutions of alcohol amines (such as MEA, DEA, MDEA and their mixed solutions) are widely used as chemical absorbents for carbon capture in flue gas from coal-fired power plants due to their high absorption efficiency. Rapid and accurate characterization of their absorption kinetics and thermodynamic properties is directly related to the selection of absorbents, formulation optimization, and reduction of energy consumption and improvement of efficiency in the capture process.

[0003] Currently, gas-liquid reaction characterization methods for carbon capture in flue gas from coal-fired power plants have the following limitations:

[0004] 1) Traditional methods are cumbersome and have low throughput: such as measuring the difference in flue gas flow rate before and after the reaction using a flow meter, observing changes in gas column length using microfluidic channels, or analyzing kinetics by counting bubbles. These methods rely on monitoring gas phase changes, making it difficult to reflect the real-time reaction process of alkanolamines and CO2 in the liquid phase (such as amine concentration decay and product formation rate). Furthermore, each experiment can only test one absorbent formulation, resulting in low throughput and failing to meet the needs of power plants for rapid screening of hundreds of compound absorbents.

[0005] 2) Some methods are costly or non-in-situ: Although headspace gas chromatography can achieve a certain high throughput, it has a measurement lag of 10-30 minutes and cannot capture the dynamic absorption behavior under fluctuations in flue gas from coal combustion (such as fluctuations in CO2 concentration caused by load changes); Although stop-flow spectrometer can characterize in real time from the perspective of liquid phase, the equipment cost is relatively high and it is mainly used for rapid reaction research in the laboratory, making it difficult to adapt to the parallel analysis of multiple samples in power plant sites or pilot-scale.

[0006] 3) Lack of multi-parameter synchronous in-situ monitoring capability: Carbon capture processes in coal-fired power plants need to simultaneously monitor key parameters such as absorption capacity (determining the rich liquor circulation rate), absorption rate (affecting mass transfer efficiency within the tower), and reaction exothermics (related to regeneration energy consumption). Most existing technologies require multiple experiments for separate measurements, making it impossible to simultaneously obtain multi-dimensional data of multiple absorbents in-situ in a single experiment, resulting in long process optimization cycles and high costs.

[0007] Despite extensive research on existing technologies at the laboratory level, there is still a lack of effective means for low-cost, real-time, in-situ, high-throughput continuous observation of liquid phase information in gas-liquid reactions for the carbon capture scenario of flue gas from coal-fired power plants.

[0008] Therefore, developing a characterization method and device adapted to the characteristics of power plant flue gas (such as CO2 concentration fluctuations and the coexistence of multiple impurities) is of great significance for deepening the understanding of the absorption mechanism of alkanolamines, accelerating the development of high-efficiency absorbents, and promoting cost reduction and efficiency improvement in carbon capture processes. Summary of the Invention

[0009] The primary objective of this invention is to overcome the shortcomings of the aforementioned background technology and to provide a high-throughput screening device for CO2 absorbents based on optical reflection imaging.

[0010] A second objective of this invention is to provide a screening method for such a high-throughput screening device for CO2 absorbents based on optical reflection imaging.

[0011] To achieve the aforementioned first objective, the technical solution of the present invention is: a high-throughput screening device for CO2 absorbents based on optical reflection imaging, characterized in that: it includes a porous plate, an imaging system, and a gas injection unit; the porous plate is provided with multiple sample wells at intervals.

[0012] The imaging system includes a sample stage supporting a porous plate, a light source, a beam collimation and beam expansion system, a beam contraction system, and a CCD camera; the light source illuminates the bottom of the sample aperture through the beam collimation and beam expansion system; the CCD camera receives and acquires the optical intensity signal reflected by the sample inside the sample aperture through the beam contraction system.

[0013] The gas injection unit includes a gas source and a multi-channel gas pipeline; one end of the multi-channel gas pipeline is connected to the gas source, and the other end is inserted into the sample well.

[0014] The above technical solution also includes a temperature measurement module; the temperature measurement module includes a multi-channel temperature sensor; the multi-channel temperature sensor is inserted into the sample well.

[0015] In the above technical solution, the gas injection unit further includes a mass flow controller; the mass flow controller is installed on the multi-channel gas pipeline.

[0016] In the above technical solution, the porous plate is a 96-hole quartz plate; the gas source includes CO2 and N2.

[0017] In the above technical solution, the CCD camera and the multi-channel temperature sensor are connected to the computer control system.

[0018] To achieve the second objective mentioned above, the technical solution of the present invention is: a high-throughput screening method for CO2 absorbers based on optical reflection imaging, characterized by comprising the following steps:

[0019] Step 1: Add different types or ratios of absorbent solutions to each sample well of the multi-well plate;

[0020] Step 2: Start the gas injection unit and introduce CO2 gas into each sample well;

[0021] Step 3: Start the imaging system and temperature measurement module; After the light emitted by the light source is reflected by the absorber solution, the optical intensity signal changes due to the change in the refractive index of the absorber solution, and the optical intensity signal is captured by the CCD camera; The temperature change caused by the exothermic reaction during the reaction is detected by the multi-channel temperature sensor;

[0022] Step 4: Using the pre-established "optical intensity-refractive index" calibration curve, the collected optical intensity signal is converted into the refractive index of the absorbent solution, and then the CO2 absorption of the absorbent solution is calculated based on the quantitative relationship between the refractive index and the absorption amount.

[0023] Step 5: By comprehensively analyzing the CO2 absorption curve of the absorbent solution over time and the temperature curve recorded simultaneously, high-throughput, multi-parameter parallel evaluation of the performance of multiple absorbent solutions can be achieved.

[0024] In the above technical solution, the method for creating the "optical intensity-refractive index" calibration curve in step 4 is as follows:

[0025] A series of solutions with known refractive indices were prepared and added to each sample well. The optical intensity of the corresponding CCD camera was measured. The refractive index was plotted on the x-axis and the optical intensity on the y-axis to obtain the "optical intensity-refractive index" calibration curve.

[0026] In the above technical solution, in step 4, the quantitative relationship between refractive index and absorption is: y = 0.23x, where absorption is x and refractive index is y.

[0027] In the above technical solution, in step 3, the CCD camera continuously acquires images at a frame rate of 1fps, and the grayscale value of the image is the optical intensity signal captured by the CCD camera.

[0028] Compared with the prior art, the present invention has the following advantages.

[0029] 1) High throughput and high efficiency: This invention utilizes the spatial resolution of optical imaging to simultaneously measure 96-well plates or even more samples, greatly improving screening efficiency.

[0030] 2) Real-time and in-situ: The optical detection used in this invention has high temporal resolution, enabling continuous and in-situ monitoring of the entire reaction process and capturing transient information.

[0031] 3) Low cost: The core of this invention is the imaging system, which significantly reduces costs compared to large-scale equipment.

[0032] 4) Multi-parameter synchronization: This invention can obtain multiple key performance parameters such as absorption capacity, absorption rate (by differentiating the absorption curve) and reaction temperature rise in one device, providing a more comprehensive evaluation dimension.

[0033] 5) Wide applicability: The theoretical basis of the method of this invention is applicable to any gas-liquid reaction system that is accompanied by a significant change in density / refractive index during the reaction process. It is not limited to CO2 absorption, but can also be extended to other systems such as H2S absorption and hydrogenation reaction. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of the present invention.

[0035] Figure 2a Images of solutions with different refractive indices used in calibration of the calibration curve.

[0036] Figure 2b A schematic diagram of the "optical intensity-refractive index" calibration curve.

[0037] Figure 2c This is a correlation comparison chart between the refractive index measured in this invention and the values ​​measured by the Abbe refractometer.

[0038] Figure 3 This is a graph verifying the correlation between refractive index and absorption.

[0039] Figure 4 This is a graph showing the absorption amount, absorption rate, and temperature changes of a certain absorbent solution.

[0040] Among them, 100-multi-well plate, 110-sample well, 200-imaging system, 210-sample stage, 220-light source, 230-beam collimation and expansion system, 240-beam contraction system, 250-CCD camera, 300-gas injection unit, 310-gas source, 320-multi-channel gas pipeline, 330-mass flow controller, 400-temperature measurement module, 410-multi-channel temperature sensor, and 500-computer control system. Detailed Implementation

[0041] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but these descriptions are not intended to limit the invention and are merely illustrative. The advantages of the present invention will become clearer and easier to understand through this description.

[0042] Referring to the accompanying drawings, the CO2 absorbent high-throughput screening device based on optical reflection imaging is characterized by comprising a porous plate 100, an imaging system 200, and a gas injection unit 300; the porous plate 100 is provided with a plurality of sample holes 110 at intervals.

[0043] The imaging system 200 is responsible for generating parallel light and illuminating the bottom of the sample, and receiving and acquiring the optical intensity signal reflected by the sample. The imaging system 200 includes a sample stage 210 supporting the porous plate 100, a light source 220, a beam collimation and expansion system 230, a beam contraction system 240, and a CCD camera 250. The light source 220 illuminates the bottom of the sample aperture 110 through the beam collimation and expansion system 230. The CCD camera 250 receives and acquires the optical intensity signal reflected by the sample inside the sample aperture 110 through the beam contraction system 240.

[0044] The gas injection unit 300 includes a gas source 310 and a multi-channel gas pipeline 320; one end of the multi-channel gas pipeline 320 is connected to the gas source 310 and the other end is inserted into the sample hole 110.

[0045] It also includes a temperature measurement module 400; the temperature measurement module 400 includes a multi-channel temperature sensor 410; the multi-channel temperature sensor 410 is inserted into the sample hole 110 and is used to monitor the temperature change in the reaction process in real time; the multi-channel temperature sensor 410 can be a thermocouple.

[0046] The gas injection unit 300 also includes a mass flow controller 330; the mass flow controller 330 is installed on the multi-channel gas pipeline 320; the mass flow controller 330, i.e., MFCs, is used to precisely control the proportion and flow rate of CO2 and its dilution gas (such as N2) into each sample well of the multi-well plate to realize the bubbling reaction.

[0047] The porous plate 100 is a 96-hole quartz plate; the gas source 310 includes CO2 and N2.

[0048] The CCD camera 250 and the multi-channel temperature sensor 410 are connected to the computer control system 500.

[0049] A high-throughput screening method for CO2 absorbents based on optical reflection imaging, characterized by comprising the following steps:

[0050] Step 1: Add different types or ratios of absorbent solutions (such as aqueous solutions of alkanolamines) to each sample well 110 of the multi-well plate 100 respectively;

[0051] Step 2: Start the gas injection unit 300 and introduce CO2 gas into each sample well 110;

[0052] Step 3: Start the imaging system 200 and temperature measurement module 400; light source 220

[0053] After the emitted light is reflected by the absorber solution, the optical intensity signal changes due to the change in the refractive index of the absorber solution, and the optical intensity signal is captured by the CCD camera 250; the temperature change caused by the exothermic reaction during the reaction is detected by the multi-channel temperature sensor 410.

[0054] Step 4: Using a pre-established "optical intensity-refractive index" calibration curve (usually using solutions with different refractive indices as references), the collected optical intensity signal is converted into the refractive index of the absorbent solution, and then the CO2 absorption of the absorbent solution is calculated based on the quantitative relationship between refractive index and absorption amount.

[0055] Step 5: By comprehensively analyzing the CO2 absorption curve of the absorbent solution over time (for calculating the absorption rate) and the synchronously recorded temperature curve, high-throughput, multi-parameter parallel evaluation of the performance of multiple absorbent solutions can be achieved.

[0056] In step 4, the method for creating the "optical intensity-refractive index" calibration curve is as follows:

[0057] A series of solutions with known refractive indices were prepared and added to each sample well 110. The optical intensity of the CCD camera 250 corresponding to the absorber solution was measured. The refractive index was plotted on the x-axis and the optical intensity on the y-axis to obtain an "optical intensity-refractive index" calibration curve. 。

[0058] In step 4, the quantitative relationship between refractive index and absorption is: y = 0.23x, where absorption is x and refractive index is y.

[0059] In step 3, the CCD camera 250 continuously acquires images at a frame rate of 1 fps, and the grayscale value of the image is the optical intensity signal captured by the CCD camera 250.

[0060] The principle of this invention is to establish a quantitative correlation between the density change (directly related to the amount of CO2 absorbed) and the refractive index change of the solution during the absorption of CO2; by detecting the change in refractive index through optical means, the amount of CO2 absorbed by the solution can be indirectly and accurately calculated.

[0061] Example

[0062] like Figure 1 As shown, a CCD 250 area array camera (such as Allied Vision Technologies Pike F-032B) is selected as the signal receiver.

[0063] Optical path setup: Light emitted from white light source 220 (such as Nikon C-HGFIE) passes through beam collimation and expansion system 230 to form a uniform parallel light spot, which illuminates the bottom of porous plate 100 placed on optical prism; the light signal reflected from sample hole 110 carries the solution refractive index information, and after passing through beam contraction system 240, it is received and imaged by CCD camera 250.

[0064] A multi-channel gas line 320 and a multi-channel temperature sensor 410 are inserted into the sample well 110; the multi-channel gas line 320 is connected to a mass flow controller 330 (such as Beijing Sevenstar Huachuang CS200) to precisely control the proportion and flow rate of the CO2 / N2 mixed gas leading to each sample well 110.

[0065] Secure all equipment to the optical platform to ensure optical path stability.

[0066] The operation flow of this embodiment is as follows:

[0067] 1) Establishing the calibration curve:

[0068] A series of solutions with known refractive indices were prepared and added to sample well 110, respectively. The optical intensity of the corresponding CCD camera 250 was measured, and the corresponding images were obtained as follows. Figure 2a As shown; with refractive index on the x-axis and optical intensity on the y-axis, the following was obtained by fitting. Figure 2b The standard curve for "optical intensity-refractive index" is shown; the fitted curve is: y=e -26.1×x ×1.19×10 20 ;R 2 =0.99947.

[0069] This fitting curve is applicable to all solutions and has universality; for solutions with refractive indices within the calibration range, the relationship between refractive index and optical intensity conforms to this curve; however, it should be noted that the specific values ​​of this fitting curve are related to the parameters of various components in the optical system, such as the light source and camera, but the equation form remains unchanged.

[0070] The refractive index of different samples was calculated using this calibration curve and compared with the refractive index measured by the Abbe refractometer to obtain... Figure 2c The comparison curves shown indicate that the refractive index measured by the device is relatively accurate and close to the results measured by the Abbe refractometer; the fitted curve is: y=x; R 2 =0.9858, close to the ideal value of 1, proving that the refractive index measurement error is <2%.

[0071] For two different samples with different absorbance, the change in refractive index per milliliter of solution was measured, and the results were fitted to obtain the following: Figure 3 The absorption and refractive index fitting graph shown is shown; the fitting curve is: y=0.23x; R2 =0.9933, absorption calculation error <1%.

[0072] Currently, the solutions suitable for this fitting curve are mainly various alcohol amine solutions commonly used for CO2 absorption. In actual tests, the density and refractive index changes of some ionic liquids and other CO2 absorbents during the absorption process also conform to this curve.

[0073] 2) Sample testing:

[0074] Different alkanolamine solutions to be tested are added to different sample wells 110; the mass flow controller 330 is activated to introduce CO2 gas (e.g., 100% CO2) into each sample well 110 at a specific flow rate; the CCD camera 250 (continuously acquiring images at a frame rate of 1 fps) and the multi-channel temperature sensor 410 are activated simultaneously; the reaction continues until the solution is saturated (the optical signal no longer changes).

[0075] 3) Data processing:

[0076] The average grayscale value of each sample well 110 at different times was extracted from the CCD image; the grayscale value was converted into the real-time refractive index using the "grayscale value-refractive index" standard curve.

[0077] The relationship between absorption and refractive index is used to convert the change in refractive index into CO2 absorption and plot the result. Figure 4 The absorption curve of orange is shown; numerical differentiation of the absorption curve yields... Figure 4 The instantaneous absorption rate curve in black; combined with data recorded by a temperature sensor, the temperature rise during the reaction process is analyzed, i.e. Figure 4 The blue curve in the image.

[0078] 4) Performance and Data:

[0079] Accuracy: such as Figure 2b As shown, the refractive index of the amine solution before and after saturated CO2 absorption was measured using an Abbe refractometer, and compared with the measurement results of the device of this invention. The linear fit R²>0.98 proves that the measurement is accurate.

[0080] Adsorption process curve analysis: such as Figure 4 As shown in the curve, the instantaneous absorption rate is obtained by differentiating the absorption amount (in the differentiation process, the measured scatter data is first fitted, and then the derivative of the fitted equation is obtained to get the differential curve; a higher-order polynomial is selected in the fitting process to make the fitted curve as close as possible to the scatter plot, and then the derivative of the fitted equation is obtained to get the corresponding differential equation; thus, the differential curve is plotted based on the equation), and it is found that it is in high agreement with the temperature change curve, which cross-verifies the accuracy of the measurement results from different physical dimensions.

[0081] All other unspecified parts belong to the prior art.

Claims

1. A high-throughput screening device for CO2 absorbents based on optical reflection imaging, characterized in that: It includes a porous plate (100), an imaging system (200), and a gas injection unit (300); the porous plate (100) is provided with a plurality of sample wells (110) at intervals; The imaging system (200) includes a sample stage (210) supporting a porous plate (100), a light source (220), a beam collimation and expansion system (230), a beam contraction system (240), and a CCD camera (250); the light source (220) illuminates the bottom of the sample aperture (110) through the beam collimation and expansion system (230); the CCD camera (250) receives and acquires the optical intensity signal reflected by the sample in the sample aperture (110) through the beam contraction system (240); The gas injection unit (300) includes a gas source (310) and a multi-channel gas pipeline (320); one end of the multi-channel gas pipeline (320) is connected to the gas source (310), and the other end is inserted into the sample hole (110).

2. The high-throughput CO2 absorbent screening device based on optical reflection imaging according to claim 1, characterized in that: It also includes a temperature measurement module (400); the temperature measurement module (400) includes a multi-channel temperature sensor (410); the multi-channel temperature sensor is inserted into the sample hole (110).

3. The high-throughput CO2 absorbent screening device based on optical reflection imaging according to claim 2, characterized in that: The gas injection unit (300) also includes a mass flow controller (330); the mass flow controller (330) is disposed on the multi-channel gas pipeline (320).

4. The high-throughput screening device for CO2 absorbents based on optical reflection imaging according to claim 1, characterized in that: The porous plate (100) is a 96-hole quartz plate; the gas source (310) includes CO2 and N2.

5. The high-throughput CO2 absorbent screening device based on optical reflection imaging according to claim 2, characterized in that: The CCD camera (250) and the multi-channel temperature sensor (410) are connected to the computer control system (500).

6. A high-throughput screening method for CO2 absorbents based on optical reflection imaging, characterized in that, Includes the following steps: Step 1: Add different types or ratios of absorbent solutions to each sample well (110) of the multi-well plate (100); Step 2: Start the gas injection unit (300) and introduce CO2 gas into each sample well (110); Step 3: Start the imaging system (200) and temperature measurement module (400); light source (220) After the emitted light is reflected by the absorber solution, the optical intensity signal changes due to the change in the refractive index of the absorber solution, and the optical intensity signal is captured by the CCD camera (250); the temperature change caused by the exothermic reaction during the reaction is detected by the multi-channel temperature sensor (410). Step 4: Using the pre-established "optical intensity-refractive index" calibration curve, the collected optical intensity signal is converted into the refractive index of the absorbent solution, and then the CO2 absorption of the absorbent solution is calculated based on the quantitative relationship between the refractive index and the absorption amount. Step 5: By comprehensively analyzing the CO2 absorption curve of the absorbent solution over time and the temperature curve recorded simultaneously, high-throughput, multi-parameter parallel evaluation of the performance of multiple absorbent solutions can be achieved.

7. The high-throughput screening method for CO2 absorbers based on optical reflection imaging according to claim 6, characterized in that, In step 4, the method for constructing the "optical intensity-refractive index" calibration curve is as follows: A series of solutions with known refractive indices were prepared and added to each sample well (110). The optical intensity of the CCD camera (250) corresponding to the absorber solution was measured. The refractive index was plotted on the x-axis and the optical intensity on the y-axis to obtain the "optical intensity-refractive index" calibration curve. The fitted curve is: y=e -26.1×x ×1.19×10 20 ;R 2 =0.99947.

8. The high-throughput screening method for CO2 absorbers based on optical reflection imaging according to claim 7, characterized in that, In step 4, the quantitative relationship between refractive index and absorption is: y = 0.23x, where absorption is x and refractive index is y.

9. The high-throughput screening method for CO2 absorbents based on optical reflection imaging according to claim 6, characterized in that, In step 3, the CCD camera (250) continuously acquires images at a frame rate of 1 fps, and the grayscale value of the image is the optical intensity signal captured by the CCD camera (250).

Images