HG/T 2089-1991 Test method for vanadium catalysts used in sulfuric acid production
Some standard content:
Chemical Industry Standard of the People's Republic of China
Test Methods for Vanadium Catalysts for Sulfuric Acid Production
1 Specification and Adjustment Range
HG 2089 — 91
This standard specifies the activity, radial crushing resistance and attrition rate of vanadium catalysts for sulfuric acid production. The test method for chemical component weight loss on ignition and the calibration method for activity test loading. This standard is applicable to vanadium catalysts for sulfur production that oxidize sulfur dioxide to sulfur trioxide in the contact sulfuric acid production process. 2 Reference standards
GB601 Preparation of standard solution for titration analysis (volume analysis) of chemical reagents GB3635 Determination method for crushing strength of fertilizer catalysts, molecular sieves, and adsorbents GB3636 Determination method for attrition rate of chemical catalysts, molecular sieves, and adsorbents GB6003 Test correction
ZBG75003 Analysis method for weight loss on ignition of fertilizer catalysts HG1--1431 Chemical composition analysis method for vanadium catalysts used in sulfuric acid production 3 Activity test
3.1 Activity test principle
Sulfur dioxide and oxygen in the air generate trioxide under the action of vanadium catalyst. The catalyst conversion efficiency is identified by measuring the change in the percentage of sulfur dioxide in the gas before and after the reaction (sulfur dioxide conversion rate). The chemical reaction equation is as follows: so,t
3.2 Activity test process
The activity test process is shown in the figure on the next page.
The compressed air enters the air filter pressure reducing valve (3) from the main valve (2-1). The decompressed gas is set by the pneumatic setter (4) and then goes to the buffer bottle (5) and the concentrated sulfuric acid washing bottle (6). After washing away the moisture in the air, it is measured by the rotor flowmeter (7-1) and then enters the mixing bottle (8) to mix with the sulfur dioxide gas.
The sulfur dioxide gas comes out of the steel cylinder (20), and after the pressure reduction adjustment by the pressure reducing throttle (2-2) and (2-4), it goes to the buffer bottle (19) and the concentrated sulfur dioxide washing bottle (18). It is then measured by the rotor flowmeter (7-3) and finally enters the mixing bottle (8) to mix with the air. The mixed gas is washed twice by the sulfuric acid washing bottle (9) and then divided into two routes: one route goes directly to the analysis system for analyzing the volume percentage of sulfur dioxide in the mixed gas (intake), and the other route is measured by the rotor scavenger (7-2) and then enters the converter. Sulfur dioxide and oxygen in the mixed gas generate sulfur trioxide under the action of silver catalyst. The liquid flows into the sulfur trioxide collecting bottle (11), and the gas is completely absorbed by the sulfur trioxide absorption bottle (12-1, 12-2). The tail gas from the absorption bottle is divided into two paths: one path goes to the analysis system to analyze the volume percentage of residual dihydrogen sulfide in the gas, and the other path goes to the water seal bottle (13) and then emptied.
3.3 Activity test conditions
Converter: This standard uses a jacketed single-change converter with a pipe diameter of 36×2 mm. The temperature measuring thermocouple sleeve is located in the converter. The Ministry of Chemical Industry of the People's Republic of China approved it on July 17, 1991 and implemented it on January 1, 1992.
2-32-4
HG 2089 — 91
Process flow diagram of the chemical activity test device
1-air compressor: 2-12-22-32-4-stop valve: 3-pressure reducer: 4-setter: 5-washing bottle; 6-concentrated sulfur washing bottle: 7-17-27-3-rotor flowmeter: 8-mixing bottle: 9concentrated sulfuric acid washing bottle; 3
10-electric heating converter: 11-trioxide recovery bottle; 12-! 12-2-trinitride absorption bottle; 13-water seal bottle; 14-test; 15-gas pressure; 16-level bottle; 17-or glass vortex: 18-liquid alkali Acid washing gas bottle: 19-buffer bottle; 20-center of sulfur dioxide bottle, its diameter is @8x1.5mm:
Catalyst loading plate: 30mL:
Catalyst particle size: S101.s107, S108 type strip length is 6~6.5mm. $10t-2H type particle size is 3.35~4.00mm; space velocity: 3600h~1;
Volume percentage of sulfur dioxide in the inlet gas: 10±0.1%, the rest is air; system pressure: normal pressure;
Active temperature: S107, S108 type 410;
S 101, $ 101-2H type 485℃;
Heat resistance temperature time: S107, S108 type 600, 5hS 101, S 101-2H type 700C, 5h.
3.4 Activity test process
3.4.1 According to the activity test conditions (3.3), the sample particle size is processed. The original particle size sample is piled with 100mL of sample in a 250mL measuring cylinder (the broken particle sample is piled with a 100mL measuring cylinder) and weighed to obtain the bulk density. Then weigh the mass equivalent to 30L of sample, 9
HG 2089—91
3.4.2 When loading the sample, first place the alloy branch pipe at the bottom of the converter, add the alloy sieve plate, add 3~5min porcelain balls (or quartz stone with the same particle size) filler on the sieve plate, adjust the material separation to the specified size, add the alloy sieve plate on the filler, then slowly pour the prepared 30-day sample into the converter, and gently tap the tube wall to make the catalyst bed surface almost flat and ensure that the bed thickness is 43±1mm, then Add an alloy sieve plate on the bed layer, and fill it with porcelain balls, tapping the tube wall while filling until it is full, seal it with an alloy sieve plate, and finally tighten the screw buckles of the inner and outer jackets of the converter. 3.4.3 Pass compressed air into the converter, block the converter outlet, and bury the sealing part of the converter in water for airtightness test until there is no air leakage.
3.4.4 Connect the converter to the system, connect the flow test device according to the schematic diagram, and connect the hot end of the temperature measuring thermocouple to the gas inlet at the chemical bed layer 5.
3.4.5 The thermoelectric furnace of the converter is powered on to heat up, and the heating rate is about 200C/h. 3.4.6 When the temperature rises to 200℃, compressed air can be introduced, and the air velocity is 3600h-1. When testing S107 and S108, it rises to 350℃; when testing S101 and S101~2H, it rises to 400℃ and sulfur dioxide can be introduced to make its concentration reach 10±0.1% at a time. Continue to increase the heat resistance temperature (S107, S108 600℃ for S107 and S108; 700℃ for S101 and S101-2H) for heat resistance test. After 55 days of heat resistance, the temperature is lowered to the activity test temperature at a rate of 200℃/h (410℃ for S107 and S108; 485℃ for S101 and S101-2H).
3.4.7 When the furnace temperature drops to the activity test temperature, S101 and S101-2H are allowed to operate in one of the following two ways a and b, and S107 and S108 are allowed to operate in accordance with item b. When the temperature drops to the activity test temperature, stop the gas and replace the sulfur in the sulfur trioxide absorption bottle. Then restore the raw gas, keep the furnace temperature and flow stable for 2 hours, and then start the analysis. Analyze the sulfur dioxide content in the inlet and outlet gas every 1.5 to 2 hours and calculate its conversion rate. Continue to analyze three times. The absolute difference between the conversion rates is not more than 2% for S107 and S108 models; it is not more than 1% for S101 and S101-2 models, and there is no obvious upward or downward trend. When it is considered that the analysis is stable, the test can be ended. b. After dropping to the activity test temperature, stop the sulfur dioxide gas first, stop the compressed air later, replace the sulfuric acid in the absorption bottle, and keep the furnace wet overnight. The next day, resume the flow of raw gas, adjust and maintain the furnace temperature, and analyze after the flow is stable for 2 hours. The rest is the same as a. 34.8 When the test is finished, first cut off the power supply of the converter, then stop the sulfur dioxide, keep the air flowing until the furnace temperature drops to close to room temperature, stop the air, remove the converter, separate the filler and catalyst, and after three consecutive tests, the converter and filler need to be cleaned with hot water to remove acid corrosion, and then dried for use. 3.4.9 The analysis method of sulfur trioxide concentration and the calculation and analysis principle of sulfur dioxide conversion rate are as follows:
SO,+2H,O+12 H2SO4+2HI
Analysis of sulfur dioxide concentration: Pipette 10mL of standard solution with concentration c(1,)=0.100m01/L (prepared and calibrated according to GB601) into a test tube, add 1mL of starch solution (0.5%), add water to 2/3 of the test tube, the solution is dark blue, connect the test tube to the rubber stopper with capillary, and when it is confirmed that there is no air leakage, adjust the sealing liquid in the gas measuring tube so that the liquid level rises to the scale 0". Open the crown gas analysis plug to allow gas to pass into the test tube, control the gas flow rate not to be too fast, and stop ventilation when the solution in the test tube is slightly blue, read the residual gas volume (blood L) in the gas tube, record the room overflow and atmospheric pressure at that time, and then calculate the volume percentage of sulfur dioxide according to formula (1).
1. 095 × 10
(p-pe,o)
+1. 095×10
Where: 1.095--and 1.000 mL iodine standard solution [e(I)=0.100 mal/L) equivalent. The volume of iodine dioxide under standard conditions, mL;
10————the volume of iodine standard calibration, niol; the volume of residual gas, spot L;
analysis chamber. ;
HG 2089 91
pactual atmospheric pressure during analysis, Pa:
Paopartial pressure of water vapor at the temperature during analysis. Pa;——standard atmospheric pressure, Pa.
After analyzing the volume percentage of sulfur dioxide in the inlet and outlet gases, calculate the sulfur dioxide conversion rate C
Wu Zhong according to formula (2):
a -(1- 0. 0156)
Sulfur dioxide conversion rate, %
× 100%
一Volume fraction of sulfur dioxide in the inlet gas of the converter Volume percentage of sulfur dioxide in the outlet gas of the converter 4 Determination of radial crushing strength of particles
4. 1 Determination method of strength
The determination method of radial crushing strength of particles shall be carried out in accordance with the provisions of GB3635. The strength determination adopts an intelligent particle strength testing machine with a precision of level 1 and a range of 0 to 250 N
4.2 Number of particles and strip length for strength determination
The sample for testing the radial crushing strength of catalyst particles is a finished product sample, and the number of particles is 30. Directly take out the sample from the laboratory and make its length between 5 and 6.5\m, and measure its length one by one with a micrometer. 4.3 Calculation of the crushing strength of catalyst wheel particles 4.3.1 The radial crushing strength of the first particle is calculated according to formula (3): P,
Where: P-radial crushing strength of the ith particle, N/cmFt-th radial crushing force, N;
L-length of the ith catalyst particle, m.
4.3.2 The average radial crushing strength of catalyst particles is calculated according to formula (4): P
Where:
-average radial crushing strength of particles, N/cm; total number of particles in the sample tested:
Radial crushing strength of the first particle, N/ cm.
4.3.3 Calculation of the percentage of low-strength particles
The percentage of low strength is calculated according to formula (5): n4
×100%
Wherein:
Percentage of low-strength particles, %;
HG2089—91
The number of particles whose radial crushing strength of sample particles is lower than the specified value (N/cm); MA-
The total number of particles in the sample,
5 Determination of abrasion rate
5.1 Determination method of abrasion rate
The determination method of abrasion rate shall be carried out in accordance with the provisions of GB3636. The specification of the abrasion sample tube selected in this standard is @50×300 μm, the sample weight is 40±2g, and the sample is sieved with a sieve with a pore size of 2 μm in accordance with GB6003 before and after grinding. 5. 2 Calculation of wear rate
The wear rate is calculated according to formula (6):
Wherein:
= wear rate, %;
Weighing bottle weight, g;
× 100%
= weight of sample on the sieve after sieving before grinding, m;
= weight of sample on the sieve after sieving after grinding, g.5. 3 Calculation of average wear rate
The average wear rate is calculated according to formula (7): W
Wherein: ·Wavg—average wear rate. %; W1 and W2 are the wear rates measured in parallel twice, respectively. %.5.4 Allowable error
When the wear rate is less than or equal to 1%, the relative deviation of parallel determination shall not be greater than 20% of the average value; when the wear rate is greater than 1%, the relative deviation of parallel determination shall not be greater than 10% of the average value. 6 Determination method of loss on ignition
For the determination method of loss on ignition, please refer to the provisions in ZBG75003. This method uses the catalyst base to be calcined at 800°C for 1.5 hours and then determine the loss on ignition.
Loss on ignition is calculated according to the formula (8 ) Calculation:
Where: x Loss on ignition, %;
Sample and crucible before ignition, m;
Sample and crucible after ignition, g
Sample mass, g.
7 Analysis of main chemical components wwW.bzxz.Net
￥100%
The content of chemical components such as vanadium pentoxide, potassium sulfate and silicon dioxide in the oxidizer shall be analyzed in accordance with the provisions of HG11431. 12
8 Technical standard and calibration of oxidizer activity test kit HG 2089 - 91
In order to ensure the accuracy and maintainability of the catalyst activity test results, the activity test device must meet the following technical requirements and be calibrated regularly
8.1 Temperature control instrument
The temperature of the converter can be controlled by using a precision digital program setter and a fine chain temperature automatic controller for automatic temperature control or by using a precision temperature automatic controller alone for semi-automatic control. 8.2: Temperature measuring instrument
The display and measurement of the converter temperature can use an electronic potentiometer with an accuracy of 0.5 grade temperature measuring thermocouple, K type (chrome-rivet), Φ1~3m armored thermocouple, with an accuracy of 0.5 grade. 8.3 Flow measurement instrument
Flow measurement instrument can use a wet gas flowmeter, glass rotor flowmeter or glass sharp-hole differential pressure flowmeter Wet gas flowmeter: rated flow rate 0.25~0.5m/h, measurement accuracy 1%. Glass rotor flowmeter or glass emulsion differential pressure flowmeter, calibrated once a quarter with a wet gas meter. 8.4 The above-mentioned measuring instruments shall be sent to the statutory metering unit for calibration according to the provisions of the measurement calibration period, and shall be self-calibrated regularly. 8.5 Converter and its isothermal zone
The temperature difference in the isothermal zone of the converter is ≤1℃; the length of the isothermal zone of the converter is ≥50tm;
Calibrated once every six months,
&.6 Feasibility of test results
Two converters test the same sample, and the absolute difference in sulfur dioxide conversion rate between them: S101, S101-2H type ≤1%; S107, S108 type 2%, calibrated once a quarter,: 8.7 Reliability of test results
Repeatedly test the same sample, the absolute difference between the sulfur dioxide conversion rates: S101, S101-2H type ≤1%; S107, S108 type ≤3%, check once every quarter, 13
HG 2099 —91
Appendix A
Determination of isothermal zone of converter
【Reference】
A1 In order to test the activity of the catalyst, the catalyst must be installed in the isothermal zone of the converter. For the converters that have been manufactured or the converters that have been replaced with electric furnace wires, the isothermal zone must be measured. A2 Fill the converter with fillers, seal the pipe mouth, tighten the sealing screw buckle of the inner and outer jackets of the converter, and test for leaks. Connect the converter to the activity test device and connect the circuit. After everything is ready, start to heat up with power, and the heating rate is 300℃/h. 3When the furnace temperature reaches 410℃, pass compressed air into the system at an airspeed of 3600h-1 (30mL of activator). Wait for the furnace temperature to stabilize for 2h and then start to determine the isothermal zone.
A4 Record the length of the thermocouple inserted into the converter and the corresponding temperature (i.e. the length and temperature at the origin). First insert the thermocouple into the thermocouple sleeve, insert 10mm each time, wait for about 1min, and record the temperature after stabilization. Then continue to insert until the interval temperature difference is above 2. Then pull the thermocouple outward, and record the corresponding temperature every time it is pulled out 10mm, until the interval temperature difference is above 2. Then insert the thermocouple into the thermocouple sleeve, and record the temperature every 10mm until the thermocouple reaches the origin. A5 Repeat the measurement according to the method of A4, and take the common isothermal area of the two measurements as the isothermal area at this temperature. A6 Raise the furnace temperature to 485℃ and stabilize it for 2h. Then measure the isothermal area at 485℃ according to the methods of A4 and A5, and take the common isothermal area of 410℃ and 485℃ as the isothermal area of the converter. 7 Sometimes the measured temperature does not show the same If the length of the temperature zone or isothermal zone is not long enough, the heating furnace needs to be removed, the density of the electric furnace wire is adjusted, and then the isothermal zone is re-measured until the isothermal zone that meets the requirements is obtained. A8 According to the measured length of the isothermal zone and the position of the converter, the height of the filling material at the bottom of the converter and the filling position of the catalyst are determined, and the length of the thermocouple inserted into the converter is calculated. Footprint B
Correction of the rotor flowmeter flow
(reference)
The size of the gas flow directly affects the activity of the catalyst. Therefore, when a new device is built or the rotor flowmeter is replaced, the room temperature changes greatly, or the measured activity shows abnormal phenomena, the flow of the rotor flowmeter needs to be calibrated. The calibration method can use a mixed gas flowmeter or a soap bubble gas flowmeter. The gas used for the calibration of the rotor flowmeter flowmeter in this installation is air. B1. Connect the wet gas flowmeter and the rotor flowmeter as shown in Figure B1. First adjust the level of the condensing gas flowmeter, then open the water level overflow hole, add steam tank water into the wet gas flowmeter, when water overflows from the overflow hole, stop adding water, and when the overflow hole is no longer splashing water, close the overflow hole plug. B2. According to the catalyst loading and activity test space velocity, the gas flow V under standard conditions is obtained according to formula (B1). s.vxv
1000×60
Wherein: -space velocity, hl;
Veat—catalyst loading, mL;
VGas flow rate under standard conditions, L/min, 14
Feed gas
HG 2089 - 91
Figure B1 Flow correction system of mixed gas flowmeter 1 Raw gas inlet width: 2 Gas volume adjustment gauge: 3 Rotor gas flowmeter: 4 Mercury pressure gauge: 5 Mercury thermometer: 6 Wet gas flowmeter: 7 Venting B3 Convert the flow rate V under standard conditions into the gas flow rate V under current conditions, and calculate according to formula (B2): P, y.
Wu Zhong: Po
Maximum machine pressure under standard conditions, Pa;
Actual atmospheric pressure during measurement, Pa;
Temperature under standard conditions, 273K;
Actual temperature during measurement (T=T+room temperature): mGas flow rate during measurement, L/min.
B4 Record the initial reading of the wet gas flowmeter, open the cock (1), allow air to enter the wet gas flowmeter through the rotor flowmeter, use the plug changer (2) to adjust the gas volume, start the stopwatch, and when the gas volume passing through the wet gas flowmeter within 1 second is equal to V, mark the scale mark indicated by the upper end surface of the float in the rotor flowmeter. Repeat the measurement to confirm the scale position indicated by the upper end face of the float. This position is the corresponding gas flow rate to be calibrated. In order to avoid the error caused by the different upward and downward speeds of the condensing gas flowmeter, it is better to use the gas passing through one pass during calibration. Added explanation: 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 technically coordinated by the Nanjing Chemical Industry Company Research Institute. This standard is drafted by Huang Chao, the Nanjing Chemical Industry Company Research Institute, and Zhengzhou Institute of Technology participated in the development. The main developers of this standard are Zhu Feng, Shen Xingnan, Liu Qing, Zheng Bo, and Wang Xiaoping. 15
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.