Correction method based on air sampling error of air bag and sampling system

Abstract

The invention discloses a gas sampling error correction method based on a gas bag and a sampling system. When a tested sample gas in a sample gas pipeline passes through a sampling port of the sample gas pipeline, one path of the tested sample gas enters a gas oxygen analyzer, and the other path of the tested sample gas enters a sampling gas bag; the gas oxygen analyzer detects the oxygen content detection value O2x% of the detected sample gas, the sampling air bag samples the detected sample gas and then sends the detected sample gas to the off-line detection mechanism to analyze the measured values of various components in the detected sample gas, and a correction coefficient Z is calculated; the offline analysis result is corrected by means of the correction coefficient, so that the method is accurate, rapid and convenient, and the production control level is improved; the method is suitable for analysis errors caused by gas permeation in the sampling process of rubber air bags or high polymer material air bags.

Description

Technical Field

[0001] The present invention relates to the technical field of gas sampling and analysis, and in particular to a correction method and a sampling system based on an airbag gas sampling error. Background Art

[0002] In the steel industry, process gas analysis is widely used throughout the entire production process. This analysis primarily utilizes two methods: online sampling and analysis, and offline sampling and analysis. Offline analysis, due to its flexibility and cost advantages, is often used in extreme operating conditions or for multi-point testing. Offline sampling and analysis primarily uses an intermediate carrier (typically a gas bag) to carry the sample gas before it is fed into an analysis system for analysis.

[0003] At present, traditional intermediate carriers generally use a single-end bladder, that is, the air intake and exhaust are completed at the same port. During the sample collection process, the sampled gas needs to be used to repeatedly wash the bladder to reduce the interference of residual gas. However, there are problems: (1) The single-port design makes it difficult to accurately control the inflation rate, which can easily cause gas phase stratification or uneven mixing due to turbulence, making the collected sample lack representativeness; (2) Repeated washing is time-consuming and inefficient, and it is difficult to completely eliminate residual gas, affecting the purity of the sample; (3) When manually sampling, air and the operator's exhaled gas can easily mix into the sample, and repeated washing will also increase the probability of misoperation; (4) The rubber bladder may be permeable to oxygen and water vapor, causing the sample gas composition to change and affecting the accuracy of the sample.

[0004] In summary, the current traditional single-head bladder offline sampling and analysis method has defects in accuracy, practicality, and reliability. Summary of the Invention

[0005] The purpose of the present invention is to solve the above technical problems and provide an accurate, fast and convenient correction method and sampling system based on airbag gas extraction error.

[0006] To achieve the above object, the present invention provides a correction method based on the gas bag gas sampling error, specifically: when the measured sample gas in the sample gas pipeline passes through the sampling port of the sample gas pipeline, the measured sample gas enters the gas oxygen analyzer on one side and enters the sampling air bag on the other side; the gas oxygen analyzer detects the oxygen content of the measured sample gas and the detection value O2 x %, after the sampling bag completes the sampling of the sample gas, it is sent to the offline detection agency to analyze the measured values ​​of various components in the sample gas, and the correction coefficient Z is calculated by formula (1); Z = (20.9% - O2 x %) / (20.9%-O2 p %)(1) Of this, 20.9% is the oxygen content in the atmosphere, O2 p % is the measured value of the oxygen content of the sample gas in the sampling bag.

[0007] Furthermore, the measured values ​​of various components of the sample gas in the sampling air bag are multiplied by the correction coefficient Z to obtain the correction value of the sample gas.

[0008] Furthermore, before sampling, the sampling airbag is washed by repeatedly filling and releasing ambient air.

[0009] A sampling system for the correction method as described above is also provided, comprising a sample gas pipeline, an air pump, a sampling air bag and a gas oxygen analyzer, wherein the air inlet of the air pump is connected to the sampling port of the sample gas pipeline through a hose, and the air outlet of the air pump is connected to the sampling air bag through a hose in one way and to the air inlet of the gas oxygen analyzer through a hose in the other way.

[0010] Furthermore, the sampling port is a metal sampling port.

[0011] Furthermore, a valve is arranged at the sampling port.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1) The sampling airbag is pre-washed with ambient air, avoiding repeated washing with sample gas and reducing sampling costs; 2) The sampling airbag only needs to be sampled once, which greatly improves efficiency and reduces the probability of misoperation; 3) While sampling, the O2 content of the sample gas is monitored online using a gas oxygen analyzer. A correction factor is calculated based on the difference between the O2 content of the online sample gas and the O2 content in the sampling airbag. The correction factor is then used to correct the offline analysis results. This is accurate, fast, and convenient, improving production control. It is suitable for correcting analytical errors caused by gas penetration (such as air infiltration) during the sampling process of rubber airbags or polymer material airbags. 4) The correction method of the present invention can collect gas multiple times and integrate the data, thereby effectively reducing errors caused by gas phase stratification or uneven mixing caused by turbulence. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Schematic diagram of the structure of the sampling system of the present invention. DETAILED DESCRIPTION

[0014] The present invention will be further described below with reference to specific embodiments.

[0015] The present invention is based on a method for correcting airbag air extraction errors, specifically: Before sampling, the sampling bag is washed by filling and releasing ambient air multiple times to replace the residual gas in the sampling bag with ambient air as much as possible, thereby ensuring that the initial O2 content in the sampling bag is the same as the ambient air level (usually about 20.9%), providing a benchmark for subsequent error correction.

[0016] After the pre-cleaning is completed, the sample gas is sampled, and sampling is only required once. When the sample gas in the sample gas pipeline passes through the sampling port of the sample gas pipeline, the sample gas enters the gas oxygen analyzer on one side and enters the sampling air bag on the other side; the gas oxygen analyzer detects the oxygen content of the sample gas and the detection value O2 x %, after the sampling bag completes the sampling of the sample gas, it is sent to the offline detection agency to analyze the measured values ​​of various components in the sample gas, and the correction coefficient Z is calculated by formula (1); Z = (20.9% - O2 x %) / (20.9%-O2 p %)(1) Of this, 20.9% is the oxygen content in the atmosphere, O2 p % is the measured value of the oxygen content of the sample gas in the sampling bag.

[0017] The measured values ​​of various components of the sample gas in the sampling air bag are multiplied by the correction coefficient Z to obtain the correction value of the sample gas.

[0018] Since air infiltration may occur during the sampling process, the O2 content in the measured gas sample in the sampling air bag will be different from the O2 content in the measured gas sample online. By monitoring this difference, the leakage coefficient, i.e., the correction coefficient, is calculated. The correction coefficient can reflect the degree of change in the measured gas sample composition caused by factors such as gas infiltration during the sampling process, and the subsequent offline analysis results are corrected and calculated accordingly to obtain more accurate and reliable measured gas sample composition data, effectively eliminating the analysis error caused by the sampling air bag gas sampling method.

[0019] Example Take the mixed coal gas as an example to illustrate: Detection data collection The gas composition in the sampling airbag is shown in Table 1 Table 1 Oxygen content measured by gas oxygen analyzer: O2 x = 0.10% Correction coefficient Z calculation Z = (20.9% - O2 x %) / (20.9%-O2 p %)=(20.9-0.10) / (20.9-2.07)=1.1046 Calculation of gas composition correction results Correction value = measured value * correction coefficient Z Table 2 shows the correction results when the oxygen content in the gas in the sampling bag changes from 2.07% to 0.1%.

[0020] Table 2 The above method has been verified in the field during the gas sampling and analysis process of Maanshan Iron and Steel, achieving the goals of accuracy, real-time performance and applicability.

[0021] like Figure 1 The sampling system of the correction method shown includes a sample gas pipeline 1, an air pump 2, a sampling air bag 3 and a gas oxygen analyzer 4. The air inlet of the air pump 2 is connected to the sampling port 5 of the sample gas pipeline 1 through a hose, and the air outlet of the air pump 2 is connected to the sampling air bag 3 through a hose in one way and to the air inlet of the gas oxygen analyzer 4 through a hose in the other way; the sampling port 5 is a metal sampling port, and a valve 6 is arranged at the sampling port 5.

Claims

1. A correction method based on airbag air extraction error, characterized by: The correction method is specifically as follows: when the sample gas in the sample gas pipeline passes through the sampling port of the sample gas pipeline, the sample gas enters the gas oxygen analyzer on one side and enters the sampling air bag on the other side; the gas oxygen analyzer detects the oxygen content of the sample gas, and the detection value O2 x %, after the sampling bag completes the sampling of the sample gas, it is sent to the offline detection agency to analyze the measured values ​​of various components in the sample gas, and the correction coefficient Z is calculated by formula (1); Z=(20.9%-O2) x %) / (20.9%-O2 p %)(1) Of this, 20.9% is the oxygen content in the atmosphere, O2 p % is the measured value of the oxygen content of the sample gas in the sampling bag.

2. The method for correcting airbag air extraction error according to claim 1, characterized in that: The measured values ​​of various components of the sample gas in the sampling air bag are multiplied by the correction coefficient Z to obtain the correction value of the sample gas.

3. The method for correcting airbag air extraction error according to claim 1 or 2, characterized in that: Before sampling, the sampling airbag is washed by repeatedly filling and releasing ambient air.

4. A sampling system for the correction method according to claim 1, characterized in that: The invention comprises a sample gas pipeline (1), an air pump (2), a sampling air bag (3) and a gas oxygen analyzer (4), wherein the air inlet of the air pump (2) is connected to the sampling port (5) of the sample gas pipeline (1) through a hose, and the air outlet of the air pump (2) is connected to the sampling air bag (3) through a hose on one side and to the air inlet of the gas oxygen analyzer (4) through a hose on the other side.

5. The sampling system according to claim 4, characterized in that: The sampling port (5) is a metal sampling port.

6. The sampling system according to claim 4 or 5, characterized in that: A valve (6) is arranged at the sampling port (5).

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