Method for detecting multiple fluorine-containing substances in exhaust gas by gas chromatography and application thereof

Abstract

The present application relates to the technical field of gas chromatography detection, especially to the field of IPCG01N30, more particularly to a gas chromatography detection method for multiple fluorine-containing substances in waste gas and application thereof, comprising the following steps: S1, collecting the gas sample by using a flue gas tester; S2, detecting the collected gas sample by using a gas chromatograph; when the carrier gas of the gas chromatograph is helium, the column efficiency of the chromatographic column can be improved; when the inner diameter of the chromatographic column is 2-4 mm and the length of the chromatographic column is 2-3 m, the separation effect and separation efficiency are balanced.

Description

Technical Field

[0001] This invention relates to the field of gas chromatography detection technology, particularly to the field of IPC G01N30, and more specifically, to a gas chromatography detection method and application for multiple fluorine-containing substances in exhaust gas. Background Technology

[0002] In the semiconductor industry, during device manufacturing processes such as silicon wafer cleaning, etching, and resist removal, fluorinated waste gas is emitted due to the use of hydrofluoric acid to remove oxides from the silicon wafer surface. This waste gas is a corrosive acidic gas and must be purified by waste gas treatment equipment before being released. However, there is currently a lack of detection methods that can simultaneously collect and detect multiple fluorinated waste gases, and therefore, a lack of methods for evaluating the efficiency of fluorinated waste gas treatment.

[0003] CN106153738B discloses a gas chromatography method for determining the content of non-condensable gases in fluorinated olefins, wherein the chromatographic conditions include a Porapak Q packed column, etc. This method provides a simple, accurate, rapid, reliable, and low-cost determination of the content of non-condensable gases in the gas phase of fluorinated olefins. However, the only detectable substances are fluorinated olefins and non-condensable gases, which have significantly different chemical properties and are easily separated in the chromatographic column. Summary of the Invention

[0004] This invention provides a gas chromatography method for detecting multiple fluorine-containing substances in waste gas, which can quickly and efficiently detect multiple fluorine-containing substances in waste gas, while having a low detection limit, and can meet the evaluation of enterprises' fluorine-containing waste gas treatment efficiency.

[0005] To achieve the objectives of this invention, the first aspect of this invention provides a gas chromatography method for detecting multiple fluorine-containing substances in waste gas, comprising the following steps:

[0006] S1, Use a flue gas analyzer to collect gas samples;

[0007] S2, use gas chromatography to detect the collected gas samples.

[0008] The flue gas tester shown is a high-flow-rate, low-concentration flue gas tester, model: ZE-8600.

[0009] Preferably, the flow rate collected in step S1 is 10-20 L / min.

[0010] More preferably, the flow rate collected in step S1 is 20 L / min.

[0011] Preferably, the data collection time in step S1 is 5-20 minutes.

[0012] More preferably, the data collection time in step S1 is 10 minutes.

[0013] The carrier gas for the gas chromatograph includes one of hydrogen, nitrogen, argon, helium, and carbon dioxide.

[0014] Preferably, the carrier gas for the gas chromatograph is helium.

[0015] When helium is used as the carrier gas in the gas chromatography, the column efficiency can be improved. The lower molar mass will reduce the gas phase mass transfer resistance coefficient. At the same time, the detection accuracy can be improved by using a thermal conductivity detector (TCD), possibly because the viscosity, diffusion rate and optimal linear velocity of helium are better matched with the thermal conductivity detector.

[0016] More preferably, the carrier gas in the gas chromatograph is helium, and the helium gas integral is 99.999%.

[0017] Preferably, the detector used in the gas chromatograph is a thermal conductivity detector.

[0018] The flow rate of the carrier gas is 20-50 mL / min.

[0019] Preferably, the flow rate of the carrier gas is 25-40 mL / min.

[0020] More preferably, the flow rate of the carrier gas is 30 mL / min.

[0021] The column temperature of the gas chromatograph is 30-50℃.

[0022] Preferably, the column temperature of the gas chromatograph is 30-40℃.

[0023] More preferably, the column temperature of the gas chromatograph is 35°C.

[0024] The detector temperature of the gas chromatograph is 50-70℃, and the bridge current of the detector is 50-150mA.

[0025] Preferably, the detector temperature of the gas chromatograph is 60°C, and the bridge current of the detector is 90mA.

[0026] The gas chromatograph has an inner diameter of 2-4 mm and a column length of 2-3 m.

[0027] Preferably, the gas chromatographic column has an inner diameter of 3 mm, a length of 3 m, and is made of stainless steel.

[0028] Further research revealed that a column inner diameter of 2-4 mm and a column length of 2-3 m achieved a balance between separation effect and efficiency. Longer columns resulted in higher overall column efficiency, but also longer analysis times. It was also found that column efficiency is inversely proportional to the square of the column radius; smaller inner diameters lead to higher efficiency, but larger inner diameters increase column capacity and allow for larger injection volumes. When the injection volume exceeds the column capacity, true equilibrium cannot be established within each theoretical plate, leading to chromatographic distortion and reduced column resolution and reproducibility. Particularly relevant for semiconductor plants with diverse and low-content fluorine-containing waste gases, especially where nitrogen trifluoride and sulfur hexafluoride levels are similar, using a stationary phase of the polymer Porapak Q with a particle size of 50-100 mesh further improves separation accuracy. This is likely due to the appropriate particle size combined with a specific column inner diameter and length, achieving both low separation time and high resolution.

[0029] The stationary phase of the gas chromatographic column is the polymer Porapak Q, and the particle size of the polymer Porapak Q is 50-100 mesh.

[0030] Preferably, the stationary phase of the gas chromatographic column is a polymer Porapak Q with an average particle size of 70 mesh, purchased from Haohan Chromatography (Shandong) Application Technology Development Co., Ltd.

[0031] Preferably, the gas chromatograph is model GC 9790II.

[0032] Preferably, the internal standard method is used for testing, and the internal standard is dichlorosilane.

[0033] The second aspect of this invention provides an application of a gas chromatography method for detecting multiple fluorine-containing substances in exhaust gas, which is applied to gas detection in semiconductor plants.

[0034] Beneficial effects:

[0035] 1. When helium is used as the carrier gas in the gas chromatography, the column efficiency of the chromatographic column can be improved.

[0036] 2. When the inner diameter of the chromatographic column is 2-4 mm and the length of the chromatographic column is 2-3 m, the separation effect and separation efficiency are balanced. Detailed Implementation

[0037] Example

[0038] A gas chromatography method for detecting multiple fluorine-containing substances in exhaust gas includes the following steps:

[0039] S1, Use a flue gas analyzer to collect gas samples;

[0040] S2, use gas chromatography to detect the collected gas samples.

[0041] The flue gas tester shown is a high-flow-rate, low-concentration flue gas tester, model: ZE-8600.

[0042] The flow rate collected in step S1 is 20 L / min.

[0043] The data collection time in step S1 is 10 minutes.

[0044] The carrier gas in the gas chromatography was helium, and the helium integral was 99.999%.

[0045] The detector used in the gas chromatograph is a thermal conductivity detector.

[0046] The flow rate of the carrier gas is 30 mL / min.

[0047] The column temperature of the gas chromatograph is 35°C.

[0048] The detector temperature of the gas chromatograph is 60°C, and the bridge current of the detector is 90mA.

[0049] The gas chromatograph has an inner diameter of 3 mm, a column length of 3 m, and is made of stainless steel.

[0050] The stationary phase of the gas chromatographic column is the polymer Porapak Q, which has an average particle size of 70 mesh and was purchased from Haohan Chromatography (Shandong) Application Technology Development Co., Ltd.

[0051] The gas chromatograph is model GC 9790II.

[0052] The gas chromatography was performed using the internal standard method, with dichlorosilane as the internal standard.

[0053] An application of a gas chromatography method for detecting multiple fluorine-containing substances in exhaust gas, applied to gas detection in semiconductor plants.

[0054] Performance testing methods

[0055] Referring to the method in Example 1, the exhaust gas from the Guangzhou Yuexin Semiconductor Technology Co., Ltd. plant was collected and tested before treatment. The retention times of different fluorinated compounds are shown in Table 1.

[0056] Referring to the method in Example 1, the gases before and after the exhaust gas treatment at the Guangzhou Yuexin Semiconductor Technology Co., Ltd. plant were collected and detected. The detection data are shown in Table 2, where “-” indicates that the detection limit is below 0.00001.

[0057] Performance test data

[0058] Table 1

[0059] Peak sequence Fluorine compounds Retention time / min 1 Carbon tetrafluoride 1.08 2 Nitrogen trifluoride 1.63 3 Sulfur hexafluoride 1.89 4 difluoromethane 14.43 5 Trifluoromethane 16.25

[0060] Table 2

[0061] Fluorine compounds Before treatment (10⁻⁶ V / V) After treatment (10⁻⁶ V / V) Detection limit (10⁻⁶ V / V) Nitrogen trifluoride 21.6 0.43 0.2 Trifluoromethane 2.5 0.043 0.02 Sulfur hexafluoride 17100 270 / Carbon tetrafluoride 2.2 0.026 / difluoromethane 304 0.17 /

Claims

1. A method for detecting a plurality of fluorine-containing substances in exhaust gas by gas chromatography, characterized by, The method comprises the following steps: S1, collecting a gas sample by using a flue gas tester; S2, detecting the collected gas sample by using a gas chromatograph; The fluorine-containing substance is carbon tetrafluoride, nitrogen trifluoride, sulfur hexafluoride, difluoromethane and trifluoromethane; The carrier gas of the gas chromatograph is helium; the column temperature of the gas chromatograph is 30-50℃; the detector temperature of the gas chromatograph is 50-70℃, the bridge flow of the detector of the gas chromatograph is 50-150mA; the stationary phase of the column of the gas chromatograph is high-molecular Porapak Q, and the particle size of the high-molecular Porapak Q is 50-100 mesh.

2. The method of claim 1, wherein the method is a gas chromatography method for detecting a plurality of fluorine-containing substances in exhaust gas. The flow rate collected in the step S1 is 10-20L / min.

3. A method for detecting a plurality of fluorine-containing substances in exhaust gas by gas chromatography according to claim 2, characterized by, The collection time in the step S1 is 5-20min.

4. The method of claim 1, wherein the method is a gas chromatography method for detecting a plurality of fluorine-containing substances in exhaust gas. The flow rate of the carrier gas is 20-50mL / min.

5. The method of claim 1, wherein the method is a gas chromatography method for detecting a plurality of fluorine-containing substances in exhaust gas. The inner diameter of the column of the gas chromatograph is 2-4mm.

6. The use of a method of gas chromatographic analysis of a plurality of fluorine-containing substances in exhaust gases according to claim 1, characterized in that, The method is applied to gas detection in a semiconductor factory.