HG/T 2273.4-1992 Test methods for catalysts for the first and second stage conversion of natural gas
Some standard content:
Chemical Industry Standard of the People's Republic of China
Subject content and scope of application of test methods for natural gas one-stage and two-stage conversion catalysts
HG2273.4-92
This standard specifies the test methods for the activity, radial crushing strength of particles, heat resistance and chemical composition of natural gas one-stage and two-stage conversion catalyst series products
This standard is applicable to Z102, Z107, Z108, Z109-1Y, Z109-2Y, Z110Y, Z111, Z203, Z204 and Z206 natural gas catalysts used in the one-stage and two-stage conversion and hydrogen production units of synthetic ammonia plants. One and two stage conversion catalyst series products and Z205 thermal protector used with Z204 catalyst. 2 Reference standards
GB601 Preparation method of standard solution for titration analysis (volumetric analysis) of chemical reagents GB3635 Determination method of crushing strength of fertilizer catalysts, molecular sieves and adsorbent particles ZBG75003 Analysis method of loss on ignition of fertilizer catalysts ZBG75004 Moisture analysis method of fertilizer catalysts ZBG75005 Chemical composition analysis method of natural gas conversion catalysts 3 Activity detection
3.1 Principle of activity detection
The main component of natural gas is methane. Methane and water vapor undergo conversion and shift reactions under certain conditions to generate carbon monoxide, carbon dioxide and hydrogen. The chemical reaction formula is as follows: CH,+H,O-→CO+3Hz-206.3kJ/molCO+H,O--CO,+H,+41.0kJ/mol
If natural gas contains hydrocarbons above C, similar reactions will also occur. 3.2 Activity detection device flow
The activity detection device flow is shown in Figure 1.
Water supply can be adopted in other ways, but the water supply should be kept stable, accurate and reliable. Natural gas metering can adopt pressurization metering before reaction or decompression metering after reaction, and then calculate the space velocity and water-carbon ratio through material balance.
The Ministry of Chemical Industry of the People's Republic of China approved the standard on March 3, 1992 and implemented it on January 1, 1993
Figure 1 Flow chart of activity detection device
1-1, 1-2-Flow meter; 2-1, 2-2-Regulator: 3-Desulfurizer; 4-Evaporator mixer; 5-Water tank; 6-Quantitative pipe; 7-Water pump; 8-Reaction tube; 9-Cooling separator; 10-Wet flow meter 3.3 Activity detection conditions
Reaction tube: Φ outside ×? inside × l, mm: 25×18×650, material Cr25Ni20, its structure is shown in Figure 2. Other forms of reaction tubes with the same inner diameter and length can also be used.
Figure 2 Schematic diagram of the reactor structure
Catalyst particle size: 1.0~2.0mm, in line with the test sieve of R40/3 series in GB6003, catalyst loading: 3.0ml;
Reaction pressure: 3.00±0.05MPa;
Carbon space velocity: 195±102~205×10h-l
Water vapor/carbon: 2.00±0.05;
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Reaction temperature (the center temperature of the catalyst bed outlet section is the control temperature): one long type and two stage catalyst indicating temperature Temperature outlet: 800±2℃,
inlet: 780±20C;
a short catalyst indicating temperature
outlet: 520±2℃,
inlet: 500±20℃;
total sulfur in purified natural gas: <0.5×10; Test water: in line with the third-grade water specification in GB6682, the raw gas is natural gas, and its composition is shown in Table 1: Table 1 Composition of raw natural gas
3,.4 Activity detection process
3.4.1 Smash the catalyst sample and sieve it with a test sieve with a pore size of 1.0~2.0mm, % (mol/mol)
3.4.2 Use a 10ml measuring cylinder to tightly stack 10ml of the sample, weigh it and take a sample equivalent to 3ml of mass. C,H
3.4.33ml catalyst sample and 17.0g clean porcelain particles of the same size that have been acid-washed and washed in advance are mixed evenly, and then loaded into the isothermal zone of the reactor with the inner wall wiped clean. Gently vibrate while loading to make it tightly packed. The filling height is 75-80mm. 3.4.4 After connecting the reactor to the system, close all vent valves, slowly introduce nitrogen or natural gas, and increase the pressure to 3.00MPa. The system pressure drop is less than or equal to 0.02MPa within 30min, which means the leak test is qualified. Otherwise, the leak point should be eliminated until it is qualified. After the leak test is completed, reduce the system to normal pressure.
3.4.5 Insert two thermocouples into the center of the catalyst bed outlet section and the catalyst bed inlet reactor outer wall to indicate and control the reactor inlet and outlet temperatures. Check the device, instruments, and meters, and put them in operation. 3.4.6 Hydrogen is introduced into the system to maintain its pressure at 0.60±0.10MPa, and the hydrogen space velocity is controlled at 2000h-1; the reactor starts to be powered on and heated to reduce the catalyst, and the evaporator mixer starts to heat up at the same time. When the outlet temperature of the reactor catalyst bed reaches 800℃, it is maintained for 2h, and the reduction is completed. 3.4.7 When the reduction is completed, the temperature of the evaporator mixer reaches 480℃, and water is fed into the evaporator mixer. After confirming that the water has entered the evaporator mixer, stop feeding hydrogen. Slowly add natural gas until the carbon space velocity is about 500h-1 and the water-carbon ratio is about 5, and then gradually increase the system pressure to 3.00MPa at a rate of 0.1MPa per minute. 3.4.8 After the system pressure stabilizes, gradually adjust various parameters to the specified values. After running stably for 2 hours under the test conditions, analyze the conversion composition once every 15 to 30 minutes with a gas chromatograph, and take the average value as the final conversion gas composition. Each test shall be conducted at least 6 times. If the relative error of the 6 groups of conversion gas compositions is not greater than 3%, the test result is considered stable and reliable, and the test can be terminated. 3.4.9 After the test, cut off the natural gas, water, electricity, natural cooling, and pressure reduction in turn. 4 Determination of radial crushing strength of particles
4.1 Strength determination method
The method for determining the radial crushing strength of particles is as follows: 4.2 Instrument performance for strength measurement:
Range: 0~1000N;
Maximum height of measurable sample: 25mm;
Accuracy:>1.5 level,
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4.3 Sample preparation
Randomly take out 50 catalyst samples from the samples to be tested and put them into the electric oven, dry them at 120°C for 4h, and then carry out strength measurement after natural cooling.
4.4 Calculation of radial crushing strength of catalyst particles 4.4.1 The radial crushing strength P of the first particle (N) is calculated according to formula (1): F
Where: F——radial crushing strength of the ith particle, N; the value of the ith particle is 1.
4.4.2 The average radial crushing strength P of catalyst particles is calculated according to formula (2): P
Where: number of particles in the sample;
——radial crushing strength of the ith particle, N
4.5 Calculation of the percentage of low-strength catalyst particles 4.5.1 The percentage of low-strength particles n is calculated according to formula (3): nwww.bzxz.net
- The number of particles in the test sample whose radial crushing strength is lower than the specified low strength index; where: n
- The total number of particles in the test sample,
5 Determination of heat resistance
Put 50 catalyst samples randomly into a high-temperature furnace, close the furnace door, and gradually heat them to 1300℃ in air under normal pressure for 5 to 6 hours. Keep the temperature at this temperature for 2 hours and then naturally cool it to room temperature. The taken out catalyst does not stick or break, which means it has qualified heat resistance.
6 Analysis of main chemical components
6.1 Determination of loss on ignition
Determine in accordance with ZBG75003.
6.2 Determination of moisture
Determine in accordance with ZBG75004
6.3 Determination of nickel oxide, silicon dioxide, ferric oxide, calcium oxide, potassium oxide and sodium oxide Determination in accordance with ZBG75005
6.4 Determination of total content of rare earth oxides
6.4.1 Summary of the method
Use sulfosalicylic acid to mask the aluminum ions in the sample solution, o-phenanthroline to mask the nickel ions, and ascorbic acid to reduce the tetravalent rare earth ions and trivalent iron ions. Under the condition of pH=5.4, use azodicarbonamide II as an indicator and disodium ethylenediaminetetraacetic acid (EDTA) standard titration solution to titrate the rare earth ions and calculate the total content of rare earth oxides. 6.4.2 Reagents
Ascorbic acid: solid;
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6.4.2.2 Ammonia water (GB631): 1+1 solution; HG.2273.4-92
6.4.2.3 Sulfosalicylic acid (HG3--991) solution: 10%; 6.4.2.4 O-phenanthroline (GB1293): 2% solution; Weigh 2g o-phenanthroline, add 1ml concentrated hydrochloric acid (GB622) to 50ml water to dissolve, and then dilute with water 6.4.2.5 Hexamethylenetetramine (GB1400) buffer solution: PH = 5.4; weigh 200g hexamethylenetetramine and dissolve it in 500ml water, add 50ml concentrated hydrochloric acid, and shake well; 6.4.2.6 Disodium ethylenediaminetetraacetic acid (GB1401) standard titration solution: c (EDTA) = 0.01mol/L, prepare 0.02mol/L disodium ethylenediaminetetraacetic acid standard solution according to GB601, and then accurately dilute it by one time in a volumetric flask before use. This solution is effective for rare earth The determination method of the titer of oxides is shown in Appendix D; 6.4.2.7 Azodicarbonamide III indicator (HG3-1007): 2g/L solution 6.4.3 Apparatus
6.4.3.1 Microburette: capacity 2ml, minimum scale value 0.01ml 6.4.4 Preparation and melting of analytical samples
Prepare and melt the samples according to Section 3.4 of ZBG75005. 6.4.5 Analysis steps
Accurately pipette 20ml of the sample solution prepared in (6.4.4) and place it at 2 In a 50ml beaker, add 15ml of sulfosalicylic acid solution (6.4.2.3), 5ml of o-phenanthroline solution (6.4.2.4), 0.1g of ascorbic acid, and 3 drops of azo ear swelling indicator (6.4.2.7), stir well, and use ammonia water (6.4.2.2) to titrate the solution from red-purple to blue-green. Add 10ml of hexamethylenetetramine buffer solution (6.4.2.5) and 50ml of water. Titrate with EDTA standard titration solution (6.4.2.6) until the solution changes from blue-green to red-purple, which is the end point. Record the volume consumed,
6.4.6 Expression of analysis results
The total content (x) of rare earth oxides (RE,O) is expressed as mass percentage and calculated according to formula (4): x
The titration degree of EDTA standard titration solution on rare earth oxides, g/mI; Wherein: T
-the volume of EDTA standard titration solution, m;
-the mass of the weighed sample, g.
The result should be expressed to two decimal places.
6.4.2 Allowable error
The difference between the results of two parallel determinations shall not exceed 0.15%. 6.5 Determination of aluminum oxide content
The aluminum oxide content of the first and second stage conversion catalysts of natural gas without rare earth elements shall be determined in accordance with ZBG75005. (4)
The aluminum oxide content of the first and second stage conversion catalysts of natural gas with rare earth elements added shall still be determined in accordance with ZBG75005, but the measured values are aluminum and rare earth contents. It is only necessary to subtract the rare earth content from the calculation formula of the analysis result to obtain the aluminum oxide content. 6.5.1 Expression of analysis results
The lithium oxide (A1,O,) content (xz) is expressed as mass percentage and is calculated according to formula (5): (c,V,-0.5c,V,)×0.05 098
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Wherein: c—concentration of zinc chloride standard titration solution, mol/L; C2
-concentration of EDTA standard solution used for titration of rare earth, mol/L; V. volume of zinc chloride standard titration solution, ml; V.
volume of EDTA standard titration solution consumed for titration of rare earth, ml; -mass of weighed sample, g;
-volume ratio of sample solution for determination of aluminum oxide and that for determination of rare earth; 0.05098—mass of aluminum oxide expressed in grams equivalent to 1.00ml zinc chloride standard titration solution [c(ZnC12)=1.000mol/L].
The result should be expressed to two decimal places
6.5.2 Allowable error
The difference between two parallel determination results shall not exceed 0.30%14
HG2273.4—92
Appendix A
Determination of reactor isothermal zone
(reference)
A1 When detecting the activity of natural gas first- and second-stage conversion catalysts, the catalyst to be detected must be installed in the isothermal zone of the reactor: Therefore, for newly manufactured or newly replaced electric furnace wire reactor heating furnaces, the isothermal zone of the reactor must be measured. A2 The reactor filled with 1.0~2.0mm ceramic particles that have been pre-treated with acid and water is connected to the activity determination device process.
A3 According to 3.4.4, the system pressure test and leak test are qualified. A4, nitrogen is introduced into the system, the flow rate is adjusted according to the air velocity of 20000h-1, and the system pressure is increased to 3.00MPa. A5, the evaporator is heated to 480℃, the reactor is heated to 800℃, and the isothermal zone can be measured after 2 hours of constant temperature. Then the reactor is cooled to 520℃, and the low temperature section isothermal zone is measured after 2 hours of constant temperature. A6 records the length of the thermocouple inserted into the thermocouple sleeve and the corresponding temperature. When measuring, the thermocouple is first inserted into the starting point of the thermocouple sleeve, that is, the center of the catalyst layer outlet section, and then inserted upwards, each 20mm is inserted, and maintained for 2 to 3 minutes, and the temperature after stabilization is recorded until the total length of the insertion is greater than 100mm. Then pull the thermocouple outward according to the same procedures and requirements, keep it for 2 to 3 minutes every time it is pulled out 20mm, and record the stable temperature until the thermocouple is pulled back to the starting point. Repeat the measurement once according to the above process, and take the common isothermal zone of the two measurements as the isothermal zone at this temperature: A7 Cool the reactor heating furnace to 520℃, measure the isothermal zone at 520℃ according to the same method as above, and take the common isothermal zone of 800℃ and 520℃ as the isothermal zone of the reactor. A8 If there is no isothermal zone or the isothermal zone is too short during the measurement process, the length of the heating furnace should be increased or the density of the electric furnace wire should be adjusted, and then the isothermal zone should be re-measured to make the temperature difference in the isothermal zone less than or equal to 2.0c. The length of the isothermal zone is greater than or equal to 80mm. A9 According to the measured isothermal zone length, determine the catalyst loading position in the reactor and the thermocouple insertion length. Standard replacement crack net
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Reactor length
Figure 3 Reactor isothermal zone measurement results
Appendix B
Determination of water-carbon ratio
(reference)
The accuracy of the water-carbon ratio has a great impact on the activity measurement data. Therefore, in the measurement process, the water-carbon ratio must be accurately measured and must be strictly controlled within the range specified by the index. B1 Measurement process
B1.1 The measurement device is shown in Figure 1 of 3.2.
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B1.2 The determination steps are carried out according to the process of 3.4. The reactor is filled with humanized porcelain particles, the temperature of the reactor is controlled to 480℃, and the raw gas is introduced into the device. After the device has been running stably for 1 hour, the water in the separator is drained and the initial reading of the wet flow meter is recorded. Continue to maintain the above conditions and run stably for another 1 hour, then drain the water in the separator, record the volume of gas passed by the wet flow meter, the atmospheric pressure and room temperature during the determination, and the reading of the mercury pressure gauge on the wet gas flow meter. B2 Calculation of water-carbon ratio
B2.1 The total carbon C of natural gas is calculated according to formula (B1): EC-1C, +2C, +3C, +... +nC, +CO +CO. In the formula: C.....C.
Content of different carbon components in raw natural gas, % (mol/mol); co-carbon dioxide content in raw natural gas, % (mol/mol); Co, carbon dioxide content in raw natural gas, % (mol/mol)) B2.2 The volume of raw gas at the measurement temperature is converted to the volume under standard conditions, and the conversion coefficient α is calculated according to formula (B2): a
Where: P
p+P,-P2||tt| |- atmospheric pressure at the time of measurement, Pa;
- atmospheric pressure under standard conditions, Pa
- mercury pressure on the wet flow meter, Pa; 273
- water vapor partial pressure of the wet flow meter at temperature t, Pa; P2
- temperature at the time of measurement, mn;
- absolute temperature, K.
B2.3 The amount of water vapor substance n (water vapor) corresponding to the raw gas volume V, is calculated according to formula (B3): B.V
n (water vapor)
-the volume of condensed water per hour, ml;
wherein: Vwater-
n(water vapor)
(V*·a,+
-the volume of raw gas passing through the wet flowmeter per hour, L; the amount of water vapor substance corresponding to the volume of raw gas, mol;-the density of water at room temperature, g/ml;
β-the mass of water vapor contained in each cubic meter of raw gas at the measuring temperature, g/mB2.4 Calculation of water-carbon ratio
The water-carbon ratio is calculated according to formula (B4):
H,o/C-
wherein: H,O/C-
Water-carbon ratio:
n (water vapor)
the volume of raw gas passing through the wet flowmeter per hour, L; water Steam) The amount of water vapor corresponding to the raw gas per hour, mol; At the measurement temperature, the conversion factor zc of the raw gas volume to the volume under standard conditions—total carbon in natural gas, mol
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Attached Sang C
Rotor Flow Meter Flow Calibration
(Reference)
C1 The accuracy of natural gas flow has a great influence on the catalyst activity test data. Therefore, before the rotor flow meter is used and after a period of use, especially when the room temperature changes greatly and the activity test data shows abnormal phenomena, the rotor flow meter flow needs to be calibrated. The calibration method adopts the wet flow meter measurement method. C2 The calibration process is shown in Figure 1 of 3.2.
C3 Slowly pass natural gas to raise the system to the operating pressure. C4 Pass the pressure test and leak test in accordance with 3.4.4 at room temperature. C5 Adjust the level of the wet flow meter. Open the water level overflow cock, add distilled water into it, make the water level reach the specified position, and the excess water flows out from the overflow hole. After the water level is stable for 0.5h, close the overflow cock. C6 According to the catalyst loading and the adopted air velocity, the gas flow rate V under standard conditions is obtained according to formula (C1): Sv·
1000×60
Where: Sy——air velocity, h\;
——catalyst loading, ml;
——gas flow rate under standard conditions, L/minY.
C7 The flow rate V under standard conditions is calculated. Convert to gas flow V under the measurement state, calculate according to formula (C2): V
wherein; V-gas flow rate during measurement, L/min; To
-temperature under standard conditions, 273K;
temperature during measurement (T=T. + room temperature);
-atmospheric pressure under standard conditions, Pa
p-atmospheric pressure during measurement, Pa.
C8Open the regulating valve to allow natural gas to enter the system through the rotor flowmeter, and then reduce the pressure and enter the wet gas flowmeter. Use the regulating valve to adjust the natural gas flow. After the system and flow are completely stable, record the scale indicated by the upper end face of the float in the gas rotor flowmeter, start the stopwatch, and record the reading of the wet gas flowmeter. After 10 minutes, pass the wet flowmeter. When the measured gas volume is equal to the calculated gas volume, mark the scale mark on the upper end face of the float in the rotor flowmeter and repeat the measurement three times. The relative error of the result is ≤1.0%. Appendix D
Determination of the titration degree of rare earth oxides with EDTA standard titration solution (supplement)
D1 Reagent
D1.1 Hydrochloric acid (GB632); 1+1 solution;
D1.2 Ammonia water (GB631) 1+1 solution;
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D1.3.110% solution;
D1.3.21% solution;;
HG 2273.492
D1.4 Hydroxylamine hydrochloride (HG3-967) 5% solution D1.5 Hexamethylenetetramine buffer solution: pH 5.4, preparation method see 6.4.2.5; D1.6 EDTA standard titration solution: C (EDTA) = 0.01 mol/L, preparation method see 6.4:2.6; D1.7 Methyl orange indicator: 1 g/L solution; D1.8 Azodicarbonamide III indicator (HG3-1007): 2 g/L solution; D2 Purification of rare earth fluorides
Take about 1 g of rare earth oxide for preparing catalyst, place it in a 250 ml beaker, add 10 ml of hydrochloric acid (D1.1) and 2 ml of hydroxylamine hydrochloride (D1.4), heat to dissolve, dilute with water to about 80 ml, if salts are precipitated, heat to dissolve them completely, filter out acid insoluble matter with medium-speed filter paper. Collect the filtrate in a 400ml beaker, add 2 drops of methyl orange indicator (D1.7), neutralize with ammonia water (D1.2) until the solution changes from red to orange-yellow, then add 5 drops of hydrochloric acid (D1.1) until it just appears red, heat to near boiling, add 50ml of oxalic acid (D1.3.1), leave at room temperature for 4h, filter with medium-speed quantitative filter paper, wash the precipitate with oxalic acid (D1.3.2) several times, put the precipitate together with the filter paper into a porcelain crucible, After low-temperature incineration, burn in a high-temperature furnace at 850℃ for 1.5h, take out and place in a desiccator to cool to room temperature.
D3 titer determination
Weigh about 0.25g (accurate to 0.0002g) of purified rare earth oxide, place it in a 250ml beaker, add 2ml of hydrochloric acid (D1.1) and 2ml of hydroxylamine hydrochloride (D1.4), heat until completely dissolved, transfer to a 250ml volumetric flask, add water to dilute to the scale, and shake well. Accurately pipette 25 ml of this solution into a 250 beaker, neutralize with ammonia water (D1.2) until a precipitate appears, then add hydrochloric acid (D1.1) to dissolve the precipitate, add 10 ml of hexamethylenetetramine buffer solution (D1.5), add 2 drops of azodipine III indicator (D1.8), and titrate with EDTA standard titration solution (D1.6) until the solution changes from green to purple-red as the end point, D4 calculation:
Wherein: T—titre of EDTA standard titration solution for rare earth oxides, g/mI; volume of EDTA standard titration solution, ml;
mass of rare earth oxides after purification, g. Additional remarks:
This standard is proposed by the Science and Technology Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the fertilizer catalyst standardization technical centralized unit of the Ministry of Chemical Industry. This standard is drafted by the Southwest Research Institute of Chemical Industry of the Ministry of Chemical Industry. The main drafters of this standard are Han Xuliang, Liu Dejin and Wang Shuyuan. Standard Loss Regulation Network m.bzsoas:con Free download of various US standard industry materials (D1)After 5 hours, close the overflow plug C6. According to the catalyst loading and the adopted air velocity, calculate the gas flow rate V under standard conditions according to formula (C1): Sv·
1000×60
Wherein: Sy——air velocity, h\;
——catalyst loading, ml;
——gas flow rate under standard conditions, L/minY.
C7 calculates the flow rate V under standard conditions. Convert to gas flow rate V under the measurement state, calculate according to formula (C2): V
wherein; V-gas flow rate during measurement, L/min; To
-temperature under standard conditions, 273K;
temperature during measurement (T=T. + room temperature);
-atmospheric pressure under standard conditions, Pa
p-atmospheric pressure during measurement, Pa.
C8Open the regulating valve to allow natural gas to enter the system through the rotor flowmeter, and then reduce the pressure and enter the wet gas flowmeter. Use the regulating valve to adjust the natural gas flow. After the system and flow are completely stable, record the scale indicated by the upper end face of the float in the gas rotor flowmeter, start the stopwatch, and record the reading of the wet gas flowmeter. After 10 minutes, pass the wet flowmeter. When the measured gas volume is equal to the calculated gas volume, mark the scale mark on the upper end face of the float in the rotor flowmeter and repeat the measurement three times. The relative error of the result is ≤1.0%. Appendix D
Determination of the titration degree of rare earth oxides with EDTA standard titration solution (supplement)
D1 Reagent
D1.1 Hydrochloric acid (GB632); 1+1 solution;
D1.2 Ammonia water (GB631) 1+1 solution;
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cs0/ccm Various standards industry information free offline D1.3 Oxalic acid (HG3-988) solution;
D1.3.110% solution;
D1.3.21% solution;;
HG 2273.492
D1.4 Hydroxylamine hydrochloride (HG3-967) 5% solution D1.5 Hexamethylenetetramine buffer solution: pH 5.4, preparation method see 6.4.2.5; D1.6 EDTA standard titration solution: C (EDTA) = 0.01 mol/L, preparation method see 6.4:2.6; D1.7 Methyl orange indicator: 1 g/L solution; D1.8 Azodicarbonamide III indicator (HG3-1007): 2 g/L solution; D2 Purification of rare earth fluorides
Take about 1 g of rare earth oxide for preparing catalyst, place it in a 250 ml beaker, add 10 ml of hydrochloric acid (D1.1) and 2 ml of hydroxylamine hydrochloride (D1.4), heat to dissolve, dilute with water to about 80 ml, if salts are precipitated, heat to dissolve them completely, filter out acid insoluble matter with medium-speed filter paper. Collect the filtrate in a 400ml beaker, add 2 drops of methyl orange indicator (D1.7), neutralize with ammonia water (D1.2) until the solution changes from red to orange-yellow, then add 5 drops of hydrochloric acid (D1.1) until it just appears red, heat to near boiling, add 50ml of oxalic acid (D1.3.1), leave at room temperature for 4h, filter with medium-speed quantitative filter paper, wash the precipitate with oxalic acid (D1.3.2) several times, put the precipitate together with the filter paper into a porcelain crucible, After low-temperature incineration, burn in a high-temperature furnace at 850℃ for 1.5h, take out and place in a desiccator to cool to room temperature,
D3 titration determination
Weigh about 0.25g (accurate to 0.0002g) of purified rare earth oxide, place it in a 250ml beaker, add 2ml of hydrochloric acid (D1.1) and 2ml of hydroxylamine hydrochloride (D1.4), heat until completely dissolved, transfer to a 250ml volumetric flask, add water to dilute to the scale, and shake well. Accurately pipette 25 ml of this solution into a 250 beaker, neutralize with ammonia water (D1.2) until a precipitate appears, then add hydrochloric acid (D1.1) to dissolve the precipitate, add 10 ml of hexamethylenetetramine buffer solution (D1.5), add 2 drops of azodipine III indicator (D1.8), and titrate with EDTA standard titration solution (D1.6) until the solution changes from green to purple-red as the end point, D4 calculation:
Wherein: T—titre of EDTA standard titration solution for rare earth oxides, g/mI; volume of EDTA standard titration solution, ml;
mass of purified rare earth oxides, g. Additional notes:
This standard is proposed by the Science and Technology Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the fertilizer catalyst standardization technical centralized unit of the Ministry of Chemical Industry. This standard is drafted by the Southwest Research Institute of Chemical Industry of the Ministry of Chemical Industry. The main drafters of this standard are Han Xuliang, Liu Dejin, and Wang Shuyuan. Standard Loss Regulation Network m.bzsoas:con Free download of various US standard industry materials (D1)After 5 hours, close the overflow plug C6. According to the catalyst loading and the adopted air velocity, calculate the gas flow rate V under standard conditions according to formula (C1): Sv·
1000×60
Wherein: Sy——air velocity, h\;
——catalyst loading, ml;
——gas flow rate under standard conditions, L/minY.
C7 calculates the flow rate V under standard conditions. Convert to gas flow rate V under the measurement state, calculate according to formula (C2): V
wherein; V-gas flow rate during measurement, L/min; To
-temperature under standard conditions, 273K;
temperature during measurement (T=T. + room temperature);
-atmospheric pressure under standard conditions, Pa
p-atmospheric pressure during measurement, Pa.
C8Open the regulating valve to allow natural gas to enter the system through the rotor flowmeter, and then reduce the pressure and enter the wet gas flowmeter. Use the regulating valve to adjust the natural gas flow. After the system and flow are completely stable, record the scale indicated by the upper end face of the float in the gas rotor flowmeter, start the stopwatch, and record the reading of the wet gas flowmeter. After 10 minutes, pass the wet flowmeter. When the measured gas volume is equal to the calculated gas volume, mark the scale mark on the upper end face of the float in the rotor flowmeter and repeat the measurement three times. The relative error of the result is ≤1.0%. Appendix D
Determination of the titration degree of rare earth oxides with EDTA standard titration solution (supplement)
D1 Reagent
D1.1 Hydrochloric acid (GB632); 1+1 solution;
D1.2 Ammonia water (GB631) 1+1 solution;
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cs0/ccm Various standards industry information free offline D1.3 Oxalic acid (HG3-988) solution;
D1.3.110% solution;
D1.3.21% solution;;
HG 2273.492
D1.4 Hydroxylamine hydrochloride (HG3-967) 5% solution D1.5 Hexamethylenetetramine buffer solution: pH 5.4, preparation method see 6.4.2.5; D1.6 EDTA standard titration solution: C (EDTA) = 0.01 mol/L, preparation method see 6.4:2.6; D1.7 Methyl orange indicator: 1 g/L solution; D1.8 Azodicarbonamide III indicator (HG3-1007): 2 g/L solution; D2 Purification of rare earth fluorides
Take about 1 g of rare earth oxide for preparing catalyst, place it in a 250 ml beaker, add 10 ml of hydrochloric acid (D1.1) and 2 ml of hydroxylamine hydrochloride (D1.4), heat to dissolve, dilute with water to about 80 ml, if salts are precipitated, heat to dissolve them completely, filter out acid insoluble matter with medium-speed filter paper. Collect the filtrate in a 400ml beaker, add 2 drops of methyl orange indicator (D1.7), neutralize with ammonia water (D1.2) until the solution changes from red to orange-yellow, then add 5 drops of hydrochloric acid (D1.1) until it just appears red, heat to near boiling, add 50ml of oxalic acid (D1.3.1), leave at room temperature for 4h, filter with medium-speed quantitative filter paper, wash the precipitate with oxalic acid (D1.3.2) several times, put the precipitate together with the filter paper into a porcelain crucible, After low-temperature incineration, burn in a high-temperature furnace at 850℃ for 1.5h, take out and place in a desiccator to cool to room temperature.
D3 titer determination
Weigh about 0.25g (accurate to 0.0002g) of purified rare earth oxide, place it in a 250ml beaker, add 2ml of hydrochloric acid (D1.1) and 2ml of hydroxylamine hydrochloride (D1.4), heat until completely dissolved, transfer to a 250ml volumetric flask, add water to dilute to the scale, and shake well. Accurately pipette 25 ml of this solution into a 250 beaker, neutralize with ammonia water (D1.2) until a precipitate appears, then add hydrochloric acid (D1.1) to dissolve the precipitate, add 10 ml of hexamethylenetetramine buffer solution (D1.5), add 2 drops of azodipine III indicator (D1.8), and titrate with EDTA standard titration solution (D1.6) until the solution changes from green to purple-red as the end point, D4 calculation:
Wherein: T—titre of EDTA standard titration solution for rare earth oxides, g/mI; volume of EDTA standard titration solution, ml;
mass of purified rare earth oxides, g. Additional notes:
This standard is proposed by the Science and Technology Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the fertilizer catalyst standardization technical centralized unit of the Ministry of Chemical Industry. This standard is drafted by the Southwest Research Institute of Chemical Industry of the Ministry of Chemical Industry. The main drafters of this standard are Han Xuliang, Liu Dejin, and Wang Shuyuan. Standard Loss Regulation Network m.bzsoas:con Free download of various US standard industry materials (D1)Additional Notes:
This standard was proposed by the Science and Technology Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is managed by the fertilizer catalyst standardization technical management unit of the Ministry of Chemical Industry. This standard was drafted by the Southwest Research Institute of Chemical Industry of the Ministry of Chemical Industry. The main drafters of this standard are Han Xuliang, Liu Dejin and Wang Shuyuan.Additional Notes:
This standard was proposed by the Science and Technology Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is managed by the fertilizer catalyst standardization technical management unit of the Ministry of Chemical Industry. This standard was drafted by the Southwest Research Institute of Chemical Industry of the Ministry of Chemical Industry. The main drafters of this standard are Han Xuliang, Liu Dejin and Wang Shuyuan.
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