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CB10665—1997
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This standard is equivalent to the Japanese Industrial Standard JISK1901-1983 (89) "Calcium Carbide". Among the technical indicators, the superior product is higher than the Japanese-class product index, the... first-class product is higher than Japan's second-class product index, and the qualified product is equal to Japan's first-class product index; the gas generation level setting is equivalent to Japan's three levels; in the test method On the above, the determination method of hydrogen sulfide impurity in acetylene adds the volumetric method of cadmium acetate absorption; on the gas-generating base determination device cover. This standard changes the large-head bell jar of the gas meter in J1SK1901-1983 (89) to a straight barrel bell jar. The high-quality products of this standard have reached the international advanced level, and the first-class products have reached the international average level. This revised standard has made certain modifications to GB10665-89 based on JISK1901-1983 (89). The name of this standard "Calcium Carbide" has been changed to "Calcium Carbide", and the technical index of gas generation has been changed from the original four levels to three. grade, the particle size is increased by 5 to 80mm, the sample preparation method for the determination of phosphine and hydrogen sulfide impurities in acetylene is changed to sampling on the device for measuring calcium carbide gas generation, and the separate acetylene generation bottle for sample preparation is cancelled||tt| |This standard will replace GB10665-89 from the date of implementation. This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Beijing Research Institute of Chemical Industry of the Ministry of Chemical Industry. The unit responsible for drafting this standard is Fujian Sanming Chemical General Plant. . Units participating in the drafting of this standard: Shanghai Wusong Chemical General Plant Carbide Factory, Juhua Group Company Carbide Factory, Zhangjiakou Xiahuayuan Carbide Factory, Sinochem Siping United Chemical Plant, Baotou Shuanghuan Chemical (Group) Co., Ltd., Hefei Chemical Plant, Zhuzhou Chemical plant. The main drafters of this standard are: Hu Yufang, Zeng Yuliu, He Jianze, Li Guozhao, Yang Jinrong. This standard is entrusted to the Ministry of Chemical Industry’s basic organic product standardization technical unit to be responsible for interpretation. 12
1Scope
National Standard of the Republic
Calcium carbide
(electricity
Calcium carbide
stone)
GB 10665—1997
replaces G31066589||tt ||This standard specifies the requirements, test methods, inspection rules and signs, labels, packaging, safety, etc. of calcium carbide (commonly known as calcium carbide). This standard is applicable to calcium carbide prepared by combining carbon materials and quicklime in an electric furnace. . This product is mainly used to generate acetylene, produce lime nitrogen, steel desulfurizer, etc.
Molecular formula: CaC2
Structural formula: C=C
Ca
Relative molecular mass : 64.10 (according to the 1995 International Relative Atomic Mass) 2 Reference Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. The versions shown are all at the time of publication of this standard. Valid. All standards will be revised. Parties using this standard should explore the possibility of using the latest version of the following standards GB190-90 Dangerous Goods Packaging Marking
GB/T601-88 Chemical Reagent Titration Analysis (Volume Analysis). Preparation of preparations and products used in test methods for preparation of standard solutions (negISO6353/1-82) GB/T 603--88 Chemical reagents
GB/T6003-85 test sieves
GB/T15956 -1995 Domestic Calcium Carbide Packaging Steel Drum 3 Requirements
3.1 The quality of calcium carbide should meet the requirements in Table 1. Item
Gas production volume
20C, 101.3 kPa
L./kgz
Phosphine in acetylene, %(V/V)
Hydrogen sulfide in acetylene, %(V/V)
Mesh
Particle size
mm | |tt||5~80
5~50
305
305
300
300
0.06
Standard
First Class
285
285
280
280
0.08
0.10
Qualified product
255
255
250
250
0.08
Implemented on 1998-04-07
13| |tt||The particle size of calcium carbide should meet the requirements of Table 2.
3.2
Particle size, mm2
80~~200
50~80l!
5~8027
5~5037
GB10665--1997
Table 2 particle size requirements
Block amount within limit, %
≥85
85
85
≥85
Note: When users have special requirements for granularity, it can be agreed upon by both parties. 4 Test method
2.5 mtm sieve undersize, %
5
5
5
5
Reagents and Water, unless other requirements are specified, refers to analytical reagents and distilled water that meet current national standards or water of corresponding purity. The standard titration solutions, impurity standard solutions, preparations and products required in the test shall be prepared in accordance with the provisions of GB/T601 and GB/T603 unless other regulations are specified. 4.1 Determination of gas generation volume
4.1.1 Method summary
Calcium carbide reacts with water to generate acetylene gas. According to the volume of the generated gas measured on the gas meter, calculate the gas generation volume of calcium carbide CaC2+ 2H,O→CH,t +Ca(OH)2+127kJ4.1.2 Instrument
Gas generation measuring device, as shown in Figure 1.
Gas meter (including outer barrel, bell jar, scale and counterweight compensation device), actual volume 19L, precision level 0.5. Instructions for use:
11JISK19011983(89) stipulates that the particle size is 80~120mm. 21JISK1901..1983 (89) stipulates that the particle size is 25~~80mm. 1983(89) stipulates that the particle size is 5~~25mm. JIS K 1901
3
14
13
10
GB10665-1997
8
6||tt ||1--counterweight compensation device; 2--bell jar; 3--liquid level mark; 4---outer barrel; 5--drain valve; 6--base; 7---gas line drain valve ; 8-box, 9-drain valve; 10-slagging valve; 11-generator; 12-separator, 13-water inlet pipe, 14-sample chamber, 15-connection valve; 16-discharge Gas valve Figure 1 Gas generation measuring device
4.1.3 Calibration of the gas meter scale
The assembly diagram of the gas meter calibration equipment is shown in Figure 2. 11
1-lower mouth bottle 2 three-way valve; 3-standard device: stainless steel material, volume 4.75L, accuracy level 0.1, with zero point and 4.75L engraved line; 4-exhaust valve 5-drainage Valve; 6-scale; 7--U-shaped pressure gauge: measuring range 1.96kPa (200mm water column); 8·-counterweight hammer; 9. compensation hammer; 10-thermometer.0~50℃, minute scale 0.1℃; 11 Separator Figure 2 Gas meter calibration equipment assembly diagram 15
4.1.4 Calibration steps
GB 10665--1997
4.1.4.1 Preparation: What is needed for calibration Water and auxiliary equipment such as thermometers, lower-mouth bottles, glass tubes, rubber tubes and rubber stoppers should be placed in the same calibration room two days in advance and connected as shown in Figure 2. The calibration operation should be performed at a room temperature of 20°C ± 2°C, and the temperature change during the calibration process shall not exceed 1°C. Adjust the gas meter and indicator to level. Increase or decrease the amount of saturated brine in the gas meter to keep the liquid level at the liquid level mark.
4.1.4.2 Inspection of air tightness: Open the exhaust valve 4 to connect the gas meter to the atmosphere, pull down the counterweight 8, make the pointer rise to two-thirds of the scale, and close the exhaust Valve to connect the gas meter to the standard. Use a weight to adjust it to generate a positive pressure difference of about 0.98kPa (100mm water column) in the gas meter. After 10 minutes, if the pointer and pressure difference have basically no change, the air tightness is considered to be qualified. 4.1.4.3 Calibration: It can only be carried out when the temperature inside the gas meter and the water temperature of the standard device are no more than 1°C different from the temperature in the laboratory. Open the exhaust valve 4.Connect the gas meter to the atmosphere, and the pointer of the gas meter should be aligned with the zero point of the scale. Place the standard on the separator so that the liquid level of the standard is aligned with the zero point. Close the exhaust valve 4, open the valve of the lower bottle, let the calibration water in the lower bottle flow into the standard device, and control the water flow rate to 750ml./min. When the water surface of the standard instrument reaches the 4.75I. scale, close the water valve. After the pressure gauge is balanced, read the position value of the pointer on the scale and record it. Lower the lower-mouth bottle and return the water in the standard to the lower-neck bottle. Repeat the same operation three times. The difference between the results of the two parallel measurements shall not be greater than 1.5mm, and the average value of the three times shall be used as the first calibration scale of 95L/kg. On the basis of the first 951./kg, continue to calibrate the second 190L/kg scale line, the third 285L/kg scale line and the fourth 380./kg scale line. The ratio of 380I./kg to the number of millimeters read on the scale is the correction value alL/(kg·mm). Gas meter requirements - annual calibration. The standard is calibrated once every two years.
4.1.5 Analysis steps
The measurement of calcium carbide gas generation is carried out in the measuring device shown in Figure 1. The gas meter is filled with a certain amount of saturated salt water saturated with acetylene gas. 2I tap water is added in the generator 11 in advance, and the zero point is adjusted before measurement. After skimming out the obviously visible ferrosilicon impurities in the sample, weigh 50g of calcium carbide sample with a particle size of 3mm~~7mm (accurate to 0.1g), and quickly place it into the sample chamber 1.4 of the acetylene generator. Close the lid immediately And seal the sample chamber. Turn the handle and put the sample completely into the water. After the calcium carbide is completely decomposed (about 10 minutes), balance its pressure, read the scale value, and record the atmospheric pressure and the temperature in the gas meter. Add water once to the same sample and operate it three times in a row. The results of the first test are not counted. The results of the second and third tests are calculated using the following formula to calculate the amount of gas generated in the dry state at 20°C and 101.3kPa. 4.1.6 Calculation of analysis results
Gas production volume (G) is calculated by following equation (1):
G = (PP)(273 ± 20)
101. 3(273 + t )
In the formula: (--Calcium carbide standard gas generation volume, .kg; α--..Gas meter calibration value, L/(kg·mm); Atmospheric pressure, kPa;
p..
P\.---According to Table 3, find out the vapor pressure of saturated salt water at t℃, kPa; gas meter scale reading, mm,
Determine the temperature inside the clock cover , ℃.
4.1.7 Allowable difference
The arithmetic mean of the two parallel measurement results is the measurement result, and the difference between the two parallel measurement results is not greater than 4L/kg||tt|. |(1)
tC
0
2
3
4
5
6||tt| |8
9
P',kPa
0.453
0.480
0.520
0.560
0.600||tt ||0.653
0.707
0.760
0.813
0.867
4.2 Determination of phosphine in acetylene
4.2.1 Colorimetry Law (Arbitration Law)
GB 10665—1997
Table 3 Vapor pressure of saturated salt water at different temperatures t, C
10
11
12
13
14
15
16
17
18
19
P', kPa
0.920
0.987
1.050
1.130
1.210
1.290
1.373
1.466| |tt||1.560
1.653bzxZ.net
tC
20
21
22
23
24||tt ||25
26
27
28
29
P\,kPa
1.760
1.880|| tt||2.000
2.120
2.253
2.386
2.533
2.693
2.853
3.026||tt| |t, C
30
31
32
33
34
35
36||tt| |37
38
39
p\,kPa
3.200
3.370
3.560
3.760||tt ||3.973
4.200
4.453
4.706
4.973
5.253
4.2.1.1 Method Summary
Acetylene Medium The phosphine is oxidized to phosphate ions by bromine water, and excess ammonium molybdate is added to react to form a heteropolymer compound, which is reduced with stannous fluoride solution to produce molybdenum blue for colorimetry to determine the phosphine content. 4.2.1.2 Reagents and solutions
a) Sodium sulfite solution: 100g/L;
b) Bromine water: 0.3% solution. Take 1 volume of saturated bromine water and add 6 volumes of water to dilute it; c) Stannous chloride hydrochloric acid solution: 20g/L, weigh 2g (accurate to 0.1g) of stannous chloride (SnCl2·2H,O) in 100ml .In a brown volumetric flask, dissolve 10ml of hydrochloric acid and add water to dilute to the mark, then add 1 to 2 tin grains and store in a dark place; d) Ammonium molybdate sulfuric acid solution: 15g/L, weigh 15g (accurate to 0.1g) ) Ammonium molybdate [(NH).Mo,O24·4H,0] was dissolved in about 200 mL of water. Add 182 mL of sulfuric acid to 500 ml of water to prepare dilute sulfuric acid. Add the ammonium molybdate solution to the dilute sulfuric acid with constant stirring. Dilute to 1 with water, put into a colored bottle, and store in a dark place. The solution cannot be used after it becomes turbid or discolored; e) Potassium dihydrogen phosphate standard solution: Accurately weigh potassium dihydrogen phosphate (KHzPO.) dried at 110C. 0.2866g (accurate to 0.0002g), add water and dissolve in a 1000mL volumetric flask, and dilute to the mark. Each milliliter of this solution is equivalent to 0.05mL of phosphine. 4.2.1.3 Instruments
a) Spectrophotometer;
b) Syringe: 100 ml (with No. 8 needle); c) Zhazhi absorption bottle: 50mL, height about 230mm, inner diameter about $17mm . 4.2.1.4 Analysis steps
Take 20 ml of 0.3% bromine water and place it in a Zhagosian absorption bottle. The mouth of the bottle is covered with a clamped transparent rubber tube for sample injection. Use a 100mL syringe to draw an acetylene gas sample, replace it 2 to 3 times, then take a 50mL gas sample at a speed of 20mL per minute, and record the temperature at the same time. Inject the sample gas into the absorption bottle at a rate of 2 () ml. per minute, then take about 50 mL of clean air and inject it into the absorption bottle at the same speed. Move the absorption liquid into a 100ml volumetric flask, wash the absorption bottle 2 to 3 times with a small amount of water, and add the washing liquid into the volumetric flask to make the volume in the volumetric flask reach about 50ml. Add sodium sulfite solution dropwise until the bromine water fades, then add 1 to 2 drops more, add 5.0 mL of ammonium molybdate sulfuric acid solution with a pipette, and shake well. Place it in a constant temperature water bath at a certain temperature of 25~~40C for 5 minutes. After taking it out, add 0.25mL (about 5 drops) of stannous chloride solution, dilute to the mark with water and shake well, then put it back into the constant overflow water bath and leave it for 10 minutes. , perform colorimetric measurements. Use a 10mm colorimetric cell to measure the absorbance of the above blue solution at a wavelength of about 660nm. Calculate the base content of phosphine based on the pre-made working curve. Do a blank test at the same time. 17
Production of phosphine working curve:
GB 10665-1997
are respectively 0.2, 0.4, 0.60.8, 1.Put 0 mL potassium dihydrogen phosphate standard solution into five 100 mL volumetric flasks, and add distilled water to each to make it 50 ml. The following operating conditions are the same as the sample operating procedures. Draw the working curve of phosphine based on the number of milliliters of potassium dihydrogen phosphate and the corresponding absorbance.
Note
1 Because phosphine is relatively active and easily decomposes when in contact with frosted glass and rubber, the inner walls of the syringe and hose should be coated with liquid paraffin. 2. Stannous chloride and sodium sulfite solutions are easily oxidized in the air and should not be prepared and stored in large quantities. The use period should not exceed two weeks. 3. The concentration of bromine water should not be less than 0.3% to avoid incomplete absorption of phosphine. 4 | | tt | .
4.2.1.5 Calculation of analysis results
The volume percentage of phosphine (X,) is calculated according to formula (2): XI V× 0. 05 × 100
.. (2)
In the formula: V, the volume of potassium dihydrogen phosphate standard solution found from the working curve, mL; V - sample volume, mL (volume at 20C, 101.3kPa) ; 0.05-1.00ml. Potassium dihydrogen phosphate standard solution is equivalent to the volume of phosphine. 4.2.1.6 Allowable difference
Take the arithmetic mean of the two parallel measurement results as the measurement result. The relative error of the two parallel measurement results shall not be greater than 40%. 4.2.2 Detection Tube Method
4.2.2.1 Summary of the Hall Method
The detection tube is filled with active silica gel coated with chemical reagents. When the gas containing phosphine passes through the detection tube, it reacts with the silica gel contained The chemical reagent reacts to generate a color column. The height of the color column is proportional to the phosphine content, and its content is measured using a direct reading method. 4.2.2.2 Analysis steps
Use a 100ml syringe to quantitatively take 100mL of acetylene sample gas, cut both ends of the detection tube, connect the inlet end of the detection tube to the syringe with a rubber hose, and press the sample gas to be measured against the detection tube Inject the detection tube evenly at the required speed, and read the phosphine content directly according to the height of the color column. 4.3 Determination of hydrogen sulfide in acetylene
4.3.1 Volumetric method (arbitration method)
4.3.1.1 Method summary
The hydrogen sulfide in acetylene is absorbed with cadmium acetate solution to generate cadmium sulfide. Add iodine standard titration solution to the acidic medium to oxidize cadmium sulfide, and use the sodium thiosulfate standard titration solution to backtit the remaining iodine. 4.3.1.2 Reagents and solutions
a) Hydrochloric acid solution: (1+1);
b) Starch indicator solution: 5g/L;
c) Cadmium acetate solution: 0.2mol /L. Weigh 29g (accurate to 0.1g) cadmium acetate in a 1L volumetric flask, dissolve it in a small amount of water, add 10g anhydrous sodium acetate and 10mL glacial acetic acid, dilute to the mark with water and mix well; d) Iodine standard titration solution: c (1/2z)=0.1mol/L; e) Sodium thiosulfate standard titration solution c (Na?S,O)=0.1mol/L. 4.3.1.3 Instruments
a) Polyethylene air bag: about 400mm × 800mm; b) Zag's absorption bottle: 100mL, height about 230mm, inner diameter about $28mm; c) Lower three bottles: 10I, minute scale 0. 1 L | In 101. lower mouth bottle 7, 18
GB10665-1997
is filled with saturated salt water saturated with acetylene, and the bottle door is plugged with a rubber stopper with a thermometer, a pressure balance tube and a gas conduit. , its lower mouth is connected to the lower mouth of the lower bottle 9 with a hose, and the water level of the lower bottle 7 is adjusted to zero point. AF
1—Polyethylene air bag; 2—Hydrogen sulfide sampling port; 3—Zagna absorption bottle; 4—Spring clip; 5 Thermometer; 6—Balance pressure tube; 7, 9—10I. Lower port Bottle; 8—Screw clamp Figure 3 Hydrogen sulfide absorption device
Put the gas taken out from the outlet of the exhaust valve into a polyethylene air bag after measuring the gas generation volume. Connect all parts according to Figure 3 and make them tight and airtight. Open the spring clamp 4 and use the spiral clamp 8 to control the gas flow rate to 300~400ml/min. When the sample gas passes about 8~10L, clamp the spring clamp 4 , stop absorption, balance the lower mouth bottle? Pressure, record gas volume, temperature and atmospheric pressure. Move the absorption liquid in the Zag's absorption bottle 3 into a 500ml iodine volumetric bottle, add 10.00mL of iodine standard titration solution through the buret, and use 5.00mL of iodine standard titration solution and 5ml of hydrochloric acid solution to dissolve the remaining precipitate in the absorption bottle and transfer it to iodine In the measuring flask, wash with water until there is no iodine solution. Combine the washing solution into the iodine volume bottle, add 10 mL of hydrochloric acid solution, cover the bottle, shake well, and leave it in a dark place for 10 minutes. Titrate with sodium thiosulfate standard titration solution to near the end point, add about 1 ml of starch indicator solution, and continue titrating to The blue just disappeared. 4.3.1.5 Calculation of analysis results
The volume percentage of hydrogen sulfide (X2) is calculated according to formula (3): - (V,C, - V,C,) × 0. 011 88 × 100X||tt ||V
In the formula: V, - the volume of the iodine standard titration solution added, mL; C, - the actual concentration of the iodine standard titration solution, mol/L; V2 - the consumption of sodium thiosulfate standard titration Solution volume, mL; (2 --- Actual concentration of sodium thiosulfate standard titration solution, mol /I-; (3)
One and 1.00ml. Iodine standard titration solution (c (1/2I2 ) = 1.000mol/L) equivalent hydrogen sulfide volume (at 20°C, 0. 011 88—
101.3kPa);
V--sample gas volume (at 20C, 101.3 kPa), L. 4.3.1.6 Allowable difference
Take the arithmetic mean of the two parallel measurement results as the measurement result, and the relative error of the two parallel measurement results shall not be greater than 40%. 4.3.2 Gravimetric method || tt | , burn, weigh, and calculate the hydrogen sulfide content. 4.3.2.2 Reagents and solutions
a) Ammonia water: (i+i);
b) Chloride lock solution: 100g/L;| |tt||c) Hydrochloric acid solution: (1+1);
19
GB10665-1997
d) Sodium hypochlorite solution: 30g/1, containing 3% effective chlorine. Preparation: Cool the sodium hydroxide solution (100g/1.) with ice, keep the temperature at about 0C, and slowly add chlorine gas until the effective chlorine reaches about 3%. When the effective chlorine exceeds 3%, use sodium hydroxide solution. (100/1.) Dilute appropriately and store in dark place. When using, dilute with water until the available chlorine is about 1.5%, and add excess sodium bicarbonate (sodium bicarbonate) to make it saturated. Calibration: Use a pipette to absorb 5ml of this solution into an iodine volumetric bottle. After diluting to about 100mL, add 2~3g potassium iodide and adjust it to acidity with hydrochloric acid. Titrate free iodine with 0.1mol/l sodium thiosulfate standard titration solution. At this time, 1ml. (.1mol/sodium thiosulfate standard titration solution is equivalent to 0.003546g effective. 4.3.2.3 Instrument
Same as 4.3.1.3.
4.3.2.4 Analysis steps ||tt ||The absorption operation device is shown in Figure 3. Put 75 mL of newly prepared sodium sulfate solution (effectively reduced by about 1.5 6) into each of the two Zag's absorption bottles, and fill the 10I lower mouth bottle 7 with acetylene. Saturate the saturated saline, and the bottle is concave with a rubber stopper with a thermometer, a pressure balance tube and a body catheter. The lower opening of the lower opening of the lower opening of the lower opening of the bottle 9 is connected with a rubber hose, and the water level of the lower opening of the lower opening of the lower opening of the lower opening of the lower opening of the bottle is adjusted to zero. Pour nitrogen into the port of sampling 1, and replace the air in the stomach of the rat.
Take out the acetylene gas from the outlet of the exhaust valve and put it in a polyethylene air bag, and connect it as shown in Figure 3. Each part. Make it tight and airtight, open the spring clamp 4, use the spiral clamp 8 to control the gas flow rate to 80~100mL/min, and the sample body to be tested passes about 8l.When, clamp the spring clip 4 to stop absorbing. Balance the pressure of the lower mouth bottle 7 and record the gas volume, temperature and atmospheric pressure. Pour nitrogen into the three-way port to blow away the acetylene gas so that all of it flows into the absorption bottle. Move the absorption liquid in the Zha's absorption bottle 3 into the beaker together. Wash the absorption bottle with water. Put all the washing liquid into the beaker. Neutralize it immediately with hydrochloric acid solution. Add an excess of 20 mL of hydrochloric acid solution. Heat and decompose until there is no chlorine odor. Evaporate to dryness. Add an appropriate amount of water and 10 ml of hydrochloric acid solution, heat to dissolve the residue, filter with qualitative filter paper, and wash with water until there is no chloride ion. The filtrate and washing liquid are about 250ml. Neutralize with ammonia water. Add 1mL of hydrochloric acid solution to make it weakly acidic. Bring to a boil. Slowly add 10mL of chlorine lock solution. Stir thoroughly. Keep it near boiling for 10 minutes and then let it stand for 12 hours. Filter the barium sulfate precipitate with dense quantitative filter paper, and wash with hot water until no chlorine is detected in the washing liquid until it leaves the factory. Move the sediment and filter paper together into a porcelain crucible of known weight, first ashe the filter paper at low temperature, and then burn it in a box-shaped blast furnace for 1 hour at a temperature of 800 to 850 degrees Celsius, take it out and let it cool slightly in the air before putting it in Cool to room temperature in a desiccator and weigh until constant weight. At the same time, perform a blank test
4.3.2.5 Calculation of hydrogen sulfide volume percentage (X:) according to formula (4). Calculate
Volume of sample gas, L
vi
0.103---equivalent to one gram of barium sulfate (BaSO,) at 20C and 101.3kPa. S) volume, 1./g. 4.3.2.6 The allowable difference
is the arithmetic mean of the two parallel measurement results, and the relative error of the two parallel measurement results is not greater than 40%. Detection tube method
4.3.3.1 Method summary
The detection tube is filled with active silica gel adsorbed with lead acetate indicator. When the gas containing hydrogen sulfide passes through the detection tube at a certain speed, the hydrogen sulfide and the indicator The agent acts to generate a dark brown color-changing column. The concentration of hydrogen sulfide in the gas is proportional to the height of the color-changing column. The hydrogen sulfide content is indirectly read on the detection tube.
4.3.3.2 Analysis steps
A 100mL syringe quantitatively absorbs 100ml of the sample gas after measuring the gas generation. Cut both ends of the detection tube, and connect the gas inlet end of the detection tube to the syringe so that the measured acetylene gas sample meets the requirements of the detection tube. Inject the whole amount into the detection tube evenly at a speed of 20
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