Preparation method and system of laser etching modified filler for promoting desorption of CO2 pregnant solution

Abstract

The invention discloses a preparation method and system of a laser etching surface modified filler for promoting desorption of a CO2 rich solution, and belongs to the technical field of carbon dioxide desorption. According to the method, ordered etching is carried out on the surface of the metal or alloy filler through high-frequency pulse laser, and a microstructure array with a deep cavity structure is constructed so as to strengthen the CO2 pregnant solution desorption process. The preparation method comprises the steps of filler surface pretreatment, laser etching processing in an atmosphere controllable environment and post-treatment. A used system is composed of a laser processing system and a laser etching container. The micro-structure constructed through laser etching can capture gas to form a gas nucleus, bubble nucleation and separation are remarkably promoted, the CO2 peak desorption rate is increased to 114.4% to the maximum, and the method has the advantages of being simple in process, free of chemical pollution, low in cost and high in stability; the method effectively solves the problems of complex process, coating shedding, environmental risk and the like in the existing catalytic coating modification technology, and is suitable for enhancing the CO2 desorption process based on the organic amine solution in the fields of CO2 capture, utilization and storage.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of carbon dioxide desorption, and particularly relates to a preparation method and system of laser etching modified filler for promoting CO2 rich liquid desorption. BACKGROUND

[0002] The energy structure characteristics of "rich coal, poor oil, and less gas" in China determine that coal will still be used as a basic energy source in a long period of time in the future, but the problem of excessive CO2 emission needs to be solved. As a core means of controlling CO2 emission, the CO2 capture, utilization and storage (CCUS) technology, among which the chemical absorption method based on organic amine solution is the mainstream choice for current industrial application due to high efficiency and high technology maturity. However, the technology faces problems such as high energy consumption of absorbent regeneration, and the energy consumption of the desorption process can account for more than 60% of the total energy consumption of the system. Regulating the chemical reaction rate and gas-liquid mass transfer efficiency of the desorption process to strengthen the carbon dioxide desorption process is one of the effective ways to solve the above problems.

[0003] In view of the desorption process strengthening, the existing research focuses on the tower filler surface modification technology. For example, patent CN115254142B discloses a catalytic desorption functional filler and a preparation method, which loads mesoporous materials and metal oxides on the surface of the filler through a coating binder-impregnation-calcination process, so that the peak desorption rate of CO2 is increased by 59.8%, and the desorption temperature is reduced by 5.2℃. Patent CN113318697A discloses a filler loaded with SO4 2- / metal oxide for desorption of CO2 from amine solution and a preparation method thereof, which loads metal oxides and sulfate SO4 2- groups on the surface of the ceramic filler through an impregnation-calcination process, and realizes a reduction of 13.5%-24.3% in CO2 desorption energy consumption. Patent CN113351149A discloses a filler loaded with metal oxide / metal sulfide and a preparation method thereof, which loads metal oxides and metal sulfides on the surface of the ceramic filler through an impregnation-calcination-sulfuration process, and the catalytic filler can effectively reduce the desorption temperature and desorption energy consumption. Although the above technologies achieve desorption process strengthening from the perspective of chemical catalysis, there are still three technical bottlenecks: first, the preparation process is complex, generally requiring 2-3 times of impregnation-calcination cycles, resulting in a long process and high production cost; second, the coating interface bonding force is insufficient, and the catalytic active components are easy to fall off due to absorbent flushing or thermal stress, affecting the long-term operation stability; and third, the environmental friendliness is poor, and some processes involve the use of toxic gases such as H2S, which poses an environmental safety risk.

[0004] Therefore, it is urgent to develop an efficient, low-cost and environmentally friendly filler surface modification method to break through the technical bottlenecks of the existing technology. SUMMARY

[0005] The purpose of the present application is to provide a surface modification method based on laser etching, which is used in a carbon dioxide desorption system to significantly improve the CO2 desorption rate and reduce the desorption energy consumption. The surface modification method constructs a microstructure array with a deep cavity structure on the surface of the filler, without the need for a catalytic coating, and the laser etching is a chemical pollution-free processing process, avoiding the risk of coating peeling and the complex process of chemical modification. The stainless steel and other metal fillers treated by the method can promote the rapid nucleation, growth and detachment of CO2 in the carbon dioxide-rich liquid desorption process, thereby significantly improving the desorption rate and desorption efficiency, reducing the regeneration temperature and energy consumption of the CO2 absorption liquid, and thus reducing the cost of carbon capture.

[0006] To achieve the above purpose, the present application provides a laser etching modified filler preparation method for promoting CO2-rich liquid desorption, characterized in that high-frequency pulse laser is used to etch the surface of the filler in an orderly manner to obtain a microstructure array surface with a deep cavity structure.

[0007] The present application also provides a specific method for preparing a laser etching modified filler for promoting CO2-rich liquid desorption, comprising the following steps:

[0008] S10, pretreating the surface of the filler to remove contaminants and oil stains on the surface of the filler to obtain a pretreated sample;

[0009] S20, placing the pretreated sample in a laser etching container with controllable atmosphere and placing it under an optical focusing lens, adjusting a three-dimensional displacement platform to make the surface of the pretreated sample to be processed located at the focal length of the laser;

[0010] S30, processing the pretreated sample using a laser processing system, setting the output parameters and laser processing parameters of the laser, and making the laser scan and process the surface of the pretreated sample according to the preset parameters to obtain a microstructure array surface with a deep cavity structure;

[0011] S40, post-treating the microstructure array surface after processing.

[0012] Preferably, the material of the filler in step S10 is metal or alloy, and the material of the filler is iron, aluminum, copper, zinc, nickel, titanium, cobalt, chromium, stainless steel or aluminum alloy.

[0013] Preferably, the pretreatment method in step S10 is to sequentially use deionized water, anhydrous ethanol and deionized water to ultrasonically clean the material and dry it. The ultrasonic cleaning time is 5-60 min, the drying temperature is 50-100℃, and the drying time is 0.5-5h. Among them, the optimal ultrasonic cleaning time is 10 min, the drying temperature is 60℃, and the drying time is 1h.

[0014] Preferably, in step S20, the processing atmosphere is air, nitrogen or argon.

[0015] Preferably, in step S30, the laser is a nanosecond pulsed laser, the output parameters of the laser are a laser wavelength of 355-1064 nm, a repetition frequency of 30-120 kHz, a pulse width of 1-100 ns, and a laser power of 5-50 W; and the laser processing parameters are a scanning speed of 100-1200 mm / s, a scanning interval of 10-100 μm, a number of repeated scans of 5-50 times, and a scanning interval time of 100 ms-10 s.

[0016] Preferably, in step S30, the microstructure array is a strip-shaped groove, a square array, or a pyramid array structure; and the deep cavity structure is a concave cavity capable of capturing gas to form a gas nucleus and promote bubble nucleation.

[0017] Preferably, in step S40, the post-processing is ultrasonic cleaning using anhydrous ethanol and deionized water in sequence and drying; the ultrasonic cleaning time is 10-30 min, the drying temperature is 50-80℃, and the drying time is 0.5-2 h.

[0018] The application also provides a laser etching modified filler preparation system for promoting CO 2 rich liquid desorption, characterized by comprising a laser processing system and a laser etching container.

[0019] The laser processing system comprises a laser, a galvanometer, and a focusing lens; the laser is used for outputting pulsed laser, the galvanometer is used for controlling the scanning path of the laser beam, and the focusing lens is used for focusing the laser beam to the surface of the sample.

[0020] The laser etching container comprises a glass window, a sample fixing table, and a gas nozzle; the glass window is used for allowing the laser to pass through and focus, the sample fixing table is used for placing and positioning the sample, and the gas nozzle is used for adjusting the processing atmosphere.

[0021] Preferably, the laser is adapted to nanosecond, picosecond, or femtosecond laser types, and the wavelength range of the output laser is 355-1064 nm.

[0022] Preferably, the laser etching container is a closed processing cavity, and the sample fixing table is used in cooperation with a three-dimensional displacement platform to adjust the sample surface to the laser focal length.

[0023] Preferably, the processing atmosphere in the laser etching container is air, nitrogen, or argon, which is adjusted through the gas nozzle.

[0024] Compared with the prior art, the application has the following significant advantages:

[0025] (1) The application provides a surface modification method based on laser etching, which constructs a microstructure array with deep cavities on the surface of fillers by changing laser power, repetition frequency, scanning speed, scanning line spacing and other parameters, and is suitable for various metal or alloy fillers.

[0026] (2) The fillers treated by the surface modification method provided by the application can significantly promote the bubble nucleation, growth and detachment of CO2 in the rich liquid desorption process, increase the peak desorption rate of CO2 by 114.4%, and thus reduce the desorption energy consumption.

[0027] (3) The surface modification method provided by the application is a green processing process without chemical pollution, and the preparation process is simple and controllable, thereby reducing the modification cost of the fillers.

[0028] The concept, specific structure and technical effects of the application will be further described below with reference to the accompanying drawings, so as to fully understand the purpose, features and effects of the application. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a schematic diagram of the laser processing system of the application;

[0030] Among them, 1, laser; 2, galvanometer; 3, focusing lens; 4, laser etching container; 5, glass window; 6, sample fixing table; 7, gas nozzle.

[0031] Figure 2 is a microstructure SEM graph of laser etching stainless steel fillers in embodiment 1 of the application;

[0032] Figure 3 is a deep cavity cross-sectional SEM graph of laser etching stainless steel fillers in embodiment 1 of the application;

[0033] Figure 4 is a CO2 desorption performance evaluation result graph of laser etching stainless steel fillers in embodiments 1 and 2 of the application. DETAILED DESCRIPTION

[0034] The application can be embodied in many different forms, and the protection scope of the application is not limited to the embodiments mentioned herein.

[0035] In the drawings, the same components have the same reference numerals, and components with similar structures or functions have similar reference numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the application does not limit the size and thickness of each component. In order to make the drawing clearer, the thickness of some components is appropriately exaggerated in some places in the drawing.

[0036] The present application aims to solve the technical bottlenecks of the existing CO2 desorption filler modification technology, such as complex process, poor stability, high environmental risk and ignoring gas-liquid mass transfer enhancement, and provides a filler surface modification method and special system based on laser etching, which constructs specific microstructure on the surface of the filler to promote bubble nucleation and strengthen gas-liquid mass transfer, thereby improving the CO2 desorption rate and reducing the desorption energy consumption.

[0037] The core technical idea adopted by the present application is: by using the high precision and programmable characteristics of laser etching, a microstructure array with deep cavity structure is constructed on the surface of metal or alloy filler, the gas bubble nucleation barrier is reduced by the gas capturing effect of the deep cavity, the CO2 bubble generation and detachment are accelerated, and the desorption process is strengthened.

[0038] The present application provides a preparation method of laser etching modified filler for promoting CO2 rich liquid desorption, which comprises the following steps:

[0039] Step S10: filler surface pretreatment

[0040] The purpose of this step is to remove the contaminants (such as oxide layer, dust) and oil stains (machining residual cutting fluid, fingerprint grease, etc.) on the surface of the filler, to ensure the stability of the laser etching process and the consistency of the microstructure.

[0041] Filler material: metal or alloy, specifically including iron, aluminum, copper, zinc, nickel, titanium, cobalt, chromium, molybdenum and various stainless steels (such as 304, 316 stainless steel). The above materials have good laser absorption and mechanical strength, and are suitable for the desorption environment of organic amine solution.

[0042] Pretreatment method: three-stage ultrasonic cleaning process, specifically:

[0043] Deionized water ultrasonic cleaning: remove surface soluble inorganic matter and particulate impurities, ultrasonic power 300-500W, time 5-60min (preferably 10min) ;

[0044] Anhydrous ethanol ultrasonic cleaning: use the strong penetration of ethanol to dissolve the surface oil stains, ultrasonic power 300-500W, time 5-60min (preferably 10min) ;

[0045] Deionized water ultrasonic cleaning: remove surface soluble inorganic matter and particulate impurities, ultrasonic power 300-500W, time 5-60min (preferably 10min) ;

[0046] Drying treatment: the cleaned sample is placed in a forced air drying oven and dried at 50-100℃ (preferably 60℃) for 0.5-5h (preferably 1h) to ensure that there is no water on the surface, to avoid steam interference during laser etching.

[0047] Step S20: sample positioning and atmosphere control

[0048] The pretreated sample is placed in a laser etching container, and the parameter calibration and environmental preparation before processing are completed:

[0049] Laser etching container: a closed cavity structure, equipped with a glass window (material: quartz glass, transmittance > 90% @ 355-1064 nm), a sample fixing table and a gas nozzle (flow adjustable range 0-5L / min).

[0050] Positioning adjustment: adjust the sample position through a three-dimensional displacement platform to make the surface to be processed in the laser focusing plane, ensuring the uniformity of etching depth.

[0051] Atmosphere control: gas is introduced into the container through the gas nozzle, and the optional atmosphere includes air, nitrogen or argon, the gas flow is 1-3L / min, and the cavity air is replaced 3-5 times to maintain a stable atmosphere, avoiding excessive oxidation of the sample surface or the generation of harmful gases during processing.

[0052] Step S30: laser etching processing

[0053] The laser processing system is used to program scanning on the sample surface to construct a microstructure array:

[0054] Laser processing system composition: including laser, galvanometer (scanning speed 0-5000mm / s, positioning accuracy ±0.001mm), focusing lens (focal length 100-200mm, spot diameter 10-50μm).

[0055] Laser parameters:

[0056] Laser type: nanosecond laser (preferred), picosecond laser or femtosecond laser, among which nanosecond laser has the advantages of processing efficiency and cost, suitable for industrial production;

[0057] Output parameters: wavelength 355nm, 532nm or 1064nm, repetition frequency 30-120kHz, pulse width 1-100ns, laser power 5-50W.

[0058] Processing parameters:

[0059] Scanning speed: 100-1200mm / s, determines the laser action time per unit area, and affects the etching depth;

[0060] Scanning pitch: 10-100μm, controls the arrangement density of microstructure units;

[0061] Number of repeated scans: 5-50 times, used to regulate the microstructure depth;

[0062] Scanning interval time: 100ms-10s, to avoid overheating of the sample caused by continuous processing.

[0063] Microstructure features: By programming the laser scanning path, structures such as strip-shaped grooves, square arrays or pyramid arrays can be formed, and the core feature is to contain a concave cavity (cavity depth 100-200 μm, cavity bottom diameter 1-5 μm), which can capture gas and form stable gas nuclei.

[0064] Step S40: post-processing

[0065] Remove the slag and debris generated during processing to ensure the integrity of the microstructure:

[0066] Cleaning process: sequentially use anhydrous ethanol (dissolve organic residues) and deionized water (remove inorganic impurities) for ultrasonic cleaning, power 300-500 W, time 5-60 min (preferably 10 min);

[0067] Drying treatment: as in step S10, dry at 50-100°C for 0.5-5h, finally obtain the laser etching modified filler with clean surface.

[0068] As shown in Figure 1 The application also provides a special preparation system, comprising:

[0069] Laser processing system: the laser provides pulsed laser output, the galvanometer controls the laser scanning trajectory according to the preset pattern, and the focusing lens focuses the laser beam to the sample surface to form a high-energy spot;

[0070] Laser etching container: as a closed processing environment, the glass window ensures the transmission of the laser without attenuation, the sample fixing table cooperates with the three-dimensional displacement platform to realize high-precision positioning, and the gas nozzle adjusts the cavity atmosphere through the flow controller.

[0071] The specific content of the application will be described below through specific examples.

[0072] Example 1

[0073] The laser etching modified filler preparation method for promoting CO2 rich liquid desorption of this embodiment comprises the following specific steps:

[0074] Step S10: pretreat the 304 stainless steel filler to remove surface contaminants and oil stains. Ultrasonically clean the sample with deionized water, anhydrous ethanol and deionized water in sequence for 10 min, and after cleaning, put the sample into a drying oven and dry at 60°C for 1h to obtain a clean stainless steel sample;

[0075] Step S20: fix the clean stainless steel sample in step S10 on the sample fixing table 6 in the laser etching container 4, adjust the three-dimensional displacement platform, so that the laser beam is focused on the surface of the sample through the glass window 5, and the processing atmosphere in the laser etching container 4 is controlled to be air by blowing through the gas nozzle 7;

[0076] Step S30: using a laser processing system to process the sample, preset the output parameters of the laser 1 and the laser processing parameters; wherein the laser wavelength is 1064 nm, the repetition frequency is 60 kHz, the pulse width is 100 ns, the laser power is 20 W; the scanning speed is 400 mm / s, the scanning interval is 50 μm, the number of repeated scanning is 25 times, and the scanning interval time is 10 s; turn on the laser 1, and the output laser is deflected by the galvanometer 2 to form a focused spot through the focusing lens 3, and the sample is scanned and processed according to the processing parameters described in step S30.

[0077] Step S40: the processed sample is sequentially ultrasonically cleaned with anhydrous ethanol and deionized water for 10 min and dried to remove the surface residual impurities.

[0078] Figure 2 and 3 As shown in the SEM morphology diagram of the laser etched stainless steel filler of Example 1, it can be seen that the surface of the filler is a typical ridge-groove array structure, and the unit cavity is a concave deep cavity, which can effectively capture gas to form an initial gas nucleus, promote rapid nucleation and release, and improve the overall desorption rate.

[0079] Example 2

[0080] The preparation method of the laser etching modified filler for promoting the desorption of CO2-rich liquid in this embodiment includes the following specific steps:

[0081] Step S10: pretreat the 304 stainless steel filler to remove surface contaminants and oil stains. Ultrasonically clean the sample with deionized water, anhydrous ethanol and deionized water for 10 min, and then dry the sample in a drying box at 60°C for 1 h to obtain a clean stainless steel sample;

[0082] Step S20: fix the clean stainless steel sample described in step S10 on the sample fixing table 6 in the laser etching container 4, adjust the three-dimensional displacement platform so that the laser beam is focused on the surface of the sample through the glass window 5, blow through the gas nozzle 7, and control the processing atmosphere in the laser etching container 4 to be air;

[0083] Step S30: using a laser processing system to process the sample, preset the output parameters of the laser 1 and the laser processing parameters; wherein the laser wavelength is 1064 nm, the repetition frequency is 60 kHz, the pulse width is 100 ns, the laser power is 20 W; the scanning speed is 400 mm / s, the scanning interval is 50 μm, the number of repeated scanning is 25 times, and the scanning interval time is 10 s; turn on the laser 1, and the output laser is deflected by the galvanometer 2 to form a focused spot through the focusing lens 3, and the sample is scanned and processed according to the processing parameters described in step S30.

[0084] Step S40: The processed sample is sequentially cleaned with anhydrous ethanol and deionized water for 10 min by ultrasonic cleaning and dried to remove surface residual impurities.

[0085] Performance test

[0086] To evaluate the promotion effect of laser etching modified fillers in the CO2 desorption process, the surface modified fillers of examples 1 and 2 in the present application were tested for performance based on the CO2 desorption device built by the laboratory, and a control group without adding modified fillers was set. The experimental conditions of the control group are consistent with examples 1 and 2, except that the addition of fillers is omitted. The desorption experimental operation process is as follows: take 400 ml of carbon dioxide rich liquid and add a certain amount of modified filler in the example to the reaction kettle, heat the solution to 90℃ for desorption for 60 min. The carbon dioxide rich liquid is 30wt% ethanolamine (MEA) solution, and the CO2 loading is 0.53 mol CO2 / mol MEA; the addition amount of the modified filler is calculated based on the total etching area, and the total etching area is 1.5 cm 2 .

[0087] The CO2 concentration change curve was recorded using a CO2 infrared gas analyzer, and the CO2 desorption rate per unit time was calculated according to the following formula, so as to obtain the maximum value in the desorption curve, that is, the peak CO2 desorption rate, which is an important indicator to measure the desorption effect.

[0088]

[0089] wherein, is the flow rate of N2, is the CO2 concentration measured by the CO2 gas analyzer.

[0090] Figure 4 The laser etching stainless steel filler CO2 desorption performance evaluation results of examples 1 and 2 are shown. The results show that compared with the control group, the modified fillers used in examples 1 and 2 can significantly improve the CO2 desorption rate at the initial stage, and the peak CO2 desorption rate is increased by 114.4% and 78.8% respectively, indicating that the existence of deep cavity microstructure has obvious promotion effect on CO2 desorption. Although the desorption rates of each group gradually tend to be consistent after the peak, the early stage strengthening effect helps to shorten the desorption time and reduce the overall energy consumption.

[0091] Although the present application preferably uses laser etching method to construct microstructure array with deep cavity structure, other micro-nano manufacturing technologies such as micro-nano imprinting, wet etching, etc. can also be considered to realize similar structure. Each of the above methods has its own advantages, but compared with laser etching, it has the characteristics of no mask, flexible processing, programmable pattern, environmental friendly, etc., and is more suitable for complex structure design and rapid industrialization preparation demand.

[0092] The preferred embodiments of the application have been described above in detail. It should be understood that modifications and variations can be made by those of ordinary skill in the art in light of the teachings of the present disclosure without departing from the scope or spirit of the application. It is therefore to be understood that what is desired to be protected by letters patent is defined by the scope of the claims that follow and that the specifics recited herein are to serve the purpose of illustration and not of limitation.

Claims

1. A method for preparing a laser etching modified packing to promote CO2 rich liquid desorption, characterized in that, The surface of the filler is orderly etched by using high-frequency pulse laser to obtain a microstructure array surface with deep cavity structure.

2. A method for preparing a laser etching modified packing to promote CO2 rich liquid desorption, characterized in that, The method comprises the following steps: S10, pretreating the surface of the filler to remove contaminants and oil stains on the surface of the filler to obtain a pretreated sample; S20, placing the pretreated sample in a laser etching container with controllable atmosphere and placing it below an optical focusing lens, adjusting a three-dimensional displacement platform to make the surface of the pretreated sample to be processed located near the laser converging focus point; S30, processing the pretreated sample by using a laser processing system, setting the output parameters and laser processing parameters of the laser, and making the laser scan and process the surface of the pretreated sample according to the preset parameters to obtain a microstructure array surface with deep cavity structure; S40, post-processing the microstructure array surface after processing.

3. The production method according to claim 2, characterized by, The material of the filler in step S10 is metal or alloy.

4. The production method according to claim 3, characterized by, The material of the filler is iron, aluminum, copper, zinc, nickel, titanium, cobalt, chromium, molybdenum, stainless steel or aluminum alloy.

5. The preparation method according to claim 2, characterized in that, The pretreatment method in step S10 is to sequentially use deionized water, anhydrous ethanol and deionized water to ultrasonically clean the material and dry it.

6. The production method according to claim 5, characterized by, The ultrasonic cleaning time is 5-60 min, the drying temperature is 50-100 DEG C, and the drying time is 0.5-5 h.

7. The preparation method according to claim 2, characterized in that, In step S20, the processing atmosphere is air, nitrogen or argon.

8. The preparation method according to claim 2, characterized in that, In step S30, the laser is a nanosecond pulse laser, the output parameters of the laser are laser wavelength 355-1064 nm, repetition frequency 30-120 kHz, pulse width 1-100 ns, and laser power 5-50 W; and the laser processing parameters are scanning speed 100-1200 mm / s, scanning pitch 10-100 mu m, repetition scanning times 5-50 times, and scanning interval time 100 ms-10 s.

9. The preparation method according to claim 2, characterized in that, In step S30, the microstructure array is a strip-shaped groove, a square array or a pyramid array structure; and the deep cavity structure is a concave cavity with a bottom size less than 6 mu m, which can effectively capture gas to form gas nucleus and promote bubble nucleation.

10. The method of claim 2, wherein, In step S40, the post-processing is to sequentially use anhydrous ethanol and deionized water to ultrasonically clean and dry.

11. The method of claim 10, wherein, The ultrasonic cleaning time is 10-20 min, the drying temperature is 50-80 DEG C, and the drying time is 0.5-2 h.

12. A laser etching modified packing preparation system for promoting CO2 rich liquid desorption, characterized in that, The laser processing system comprises a laser, a galvanometer and a focusing lens; the laser is used to output pulse laser, the galvanometer is used to control the scanning path of the laser beam, and the focusing lens is used to focus the laser beam to the sample surface. The laser etching container comprises a glass window, a sample fixing table and a gas nozzle; the glass window is used for laser transmission and focusing, the sample fixing table is used for placing and positioning the sample, and the gas nozzle is used for adjusting the processing atmosphere. The laser is adapted to nanosecond, picosecond or femtosecond laser type, and the wavelength range of the output laser is 355-1064 nm.

13. The system of claim 12, wherein, The laser etching container is a sealed processing cavity, and the sample fixing table is used in cooperation with the three-dimensional displacement platform to adjust the sample surface to the laser focal length.

14. The system of claim 12, wherein, The processing atmosphere in the laser etching container is air, nitrogen or argon, which is adjusted by the gas nozzle.

15. The system of claim 12, wherein, ​

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