This standard is applicable to the determination of flash point and fire point of petroleum products by Cleveland open cup instrument. However, it is not applicable to the determination of fuel oil and petroleum products with an open flash point below 79°C. GB/T 3536-1983 Determination of flash point and fire point of petroleum products (Cleveland open cup method) GB/T3536-1983 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of flash and fire points of petroleum products
(Cleveland open cup method)
Petroleum products -- Determination offlash and fire points-Cleveland open cup methodUDC 665.5
GB/T 3536---83
(Confirmed in 1991)
1S02592-1973
This method is applicable to the determination of flash and fire points of petroleum products using Cleveland open cup instrument. However, it is not applicable to the determination of fuel oil and petroleum products with an open flash point below 79°C.
This method is formulated in accordance with the international standard ISO2592--1973 "Determination of flash and fire points of petroleum products (Cleveland open cup method)". 1 Method Overview
1.1 Put the sample into the test cup to the specified mark. First quickly increase the temperature of the sample, and then slowly increase the temperature. When approaching the flash point, increase the temperature at a constant rate. At the specified temperature interval, a small test flame is passed horizontally across the test cup, and the lowest temperature at which the vapor on the surface of the sample flashes is taken as the flash point. If it is necessary to determine the ignition point, the test should be continued until the lowest temperature at which the test flame ignites the sample and burns for at least 5 seconds is taken as the ignition point.
2 Apparatus and Materials
2.1 Apparatus
2.1.1 Cleveland open cup apparatus, including a test cup, a heating plate, a test flame generator, a heater and a stand. See Appendix A for details.
2.1.2 Protective screen: It is recommended to use a protective screen that is 46 cm square and 61 cm high, with an open face and the inner wall painted black. 2.1.3 Thermometer: See Appendix B for dimensions. 2.2 Materials
Unleaded gasoline or other suitable solvents.
3 Preparation
3.1 Place the measuring device in a wind-proof and dark place and surround it with a protective screen so that the flash fire phenomenon can be clearly seen. When the temperature reaches 17°C before the expected flash point, care must be taken to avoid the flow of vapor in the test cup caused by test operations or breathing close to the test cup, which may affect the test results. Note: The vapor or pyrolysis products of some samples are harmful. It is allowed to place the instrument with a protective screen in a ventilated pavilion, but when the temperature reaches 56°C before the expected flash point, adjust the ventilation so that the vapor of the sample can be discharged and there is no air circulation above the test cup. 3.2 Wash the test cup with unleaded gasoline or other suitable solvent to remove all oil marks, trace colloids or residues left from the previous test. If there is carbon residue, it should be removed with a wire brush. Rinse the test cup with cold water and dry it on an open flame or hot plate for a few minutes to remove residual traces of solvent and water. The test cup should be cooled to at least 56°C before the expected flash point before use. 3.3 Place the thermometer in a vertical position with the base of the bulb 6 mm from the bottom of the test cup and located at the midpoint between the center and the edge of the test cup, on a diameter perpendicular to the arc (or line) swept by the test flame, and on the opposite side of the igniter arm. Note: The correct position of the thermometer should be such that the immersion mark on the thermometer is 2 meters below the edge of the test cup. Test Procedure
4.1 Fill the test cup with the sample at any temperature so that the top of the meniscus just touches the sample filling mark. If too much sample is filled into the test cup, remove the excess sample with a pipette or other appropriate tool. If the sample sticks to the outside of the instrument, pour out the sample, wash it and refill it. Air bubbles on the surface of the sample should be removed.② Note: (1) Viscous samples should be heated to flow before being poured into the sample cup, but the heating temperature should not exceed 56°C before the expected flash point of the sample. ② Samples with dissolved or free water can be dehydrated with calcium nitride and filtered with quantitative filter paper or loose dry cotton wool. 4.2 Ignite the test flame and adjust the flame diameter to about 4 mm. If a metal comparison ball is installed on the instrument, it should be the same diameter as the metal comparison ball.
4.3 When heating begins, the sample temperature rises at a rate of 1417°C per minute. When the sample temperature reaches 56°C before the expected flash point, slow down the heating rate and control the temperature rise rate so that it is 5-6°C per minute for the last 28°C before the flash point. 4.4 At 28°C before the expected flash point, begin sweeping with the test flame. Sweep once for every 2°C increase in temperature on the thermometer. The test flame must pass through the center of the test cup on a right angle line passing through the diameter of the thermometer. Sweep with a smooth, continuous motion, in a straight line or along a radius of at least 150 mm. The center of the test flame must move within 2 mm of the upper edge of the test cup, first sweeping in one direction and then in the opposite direction. The time required for the test flame to pass over the test cup each time is about 1 second. 4.5 When a flash occurs at any point on the sample liquid surface, immediately record the temperature reading on the thermometer as the flash point. However, do not confuse the light blue halo that sometimes appears around the test flame with the true flash point. 4.6 If it is also necessary to determine the flash point, continue heating so that the sample temperature rises at a rate of 5 to 6°C per minute, continue to use the test flame, and sweep once for every 2°C increase in the sample until the sample ignites and burns continuously for not less than 5 seconds. At this time, immediately read the temperature from the thermometer as the flash point determination result.
5 Atmospheric pressure correction
When the atmospheric pressure is lower than 95.3 kilopascals (kPa) (953mba, 715mmHg column), the flash point and ignition point obtained in the test should be added with the correction number as the test result, and the result should be rounded.
95.3~88.7
88.6 ~ 81.3
81.2～73.3
6 Precision
953887
886~813
812～733
The reliability of the test results (95% confidence level) shall be determined by the following provisions. 6.1 Repeatability
mmHg column
715~665
664~610
609~550
The difference between two test results measured repeatedly by the same operator using the same instrument should not exceed the following values:Flash point 8℃
Fire point 8℃
6.2 Reproducibility
The difference between two results proposed by two laboratories should not exceed the following values:Flash point 16℃
Fire point 14℃
Correction number,
Note: This precision was obtained by conducting statistical tests in 1982 with 6 samples in 10 laboratories, and performing data processing and analysis on the test results. 7 Report
Take the average value of the flash point and fire point of the two repeated measurements after correction by atmospheric pressure as the Cleveland open cup flash point and fire point, 337
GB/T 3536--- 83
Appendix A
Cleveland open cup apparatus
(supplement)
The Cleveland open cup apparatus (see Figure A1) includes: test cup, heating plate, test flame generator, heater, thermometer bracket and heating plate bracket, all of which should meet the following requirements: Thermometer
Minimum R150
Ignitor
Metal comparatorbzxz.net
Small ball hole 4
To gas source
(or test flame generator)
Heater
(flame or resistance type)
Maximum 2
Test cup
A.1 Test cup
Cleveland open cup apparatus
Heating plate
Made of brass or other stainless metal with equivalent thermal conductivity, and the dimensional requirements are shown in Figure A2. The test cup may be equipped with a handle. $97～100
Specimen marking
1e-28-18
A.2 Heating plate
Cleeland open cup
Made of brass, cast iron, wrought iron or steel plate. There is a central hole with a slightly recessed flat surface around it. Except for this surface where the test cup is placed 338
GB/T3536-83
, the heating plate is covered with a hard asbestos board. The main dimensions of the heating plate are shown in Figure A3, but the heating plate can also be square instead of round. The metal plate can be appropriately extended to install the test flame generator and the thermometer bracket. In addition, the metal comparison ball mentioned in A.3 can also be installed on the heating plate so that it passes through and slightly protrudes from the appropriate small hole in the asbestos board. Φ146~1
$69.5-70.5
$55～
Figure A3 Heating plate
A.3 Test flame generator
The device for sweeping the flame may be of any suitable form, but it is recommended that the top diameter of the flame head be 1.6 mm and the hole diameter be approximately 0.8 mm. The device for operating the test flame should be installed so that the test flame sweep can be automatically repeated, and the radius of rotation of the sweep is not less than 150 mm. The center of the hole can move in a plane not more than 2 mm above the edge of the test cup. A small metal comparison ball with a diameter of 3.2 to 4.8 mm can be installed in a convenient position of the instrument to compare with the test flame. A.4 Heater
Any convenient heating source can be used. Gas lamps or alcohol lamps are allowed, but in no case can the flame rise to the periphery of the test cup. It is best to use an electric heater controlled by an adjustable transformer. The heat source should be concentrated under the hole and there should be no local overheating. Flame-type heaters can be protected from drafts or excessive radiation by any suitable protective screen, but the protective screen should not be higher than the upper surface of the asbestos board. A.5 Thermometer holder
Enables the thermometer to be fixed in a specified position during the test and can be easily removed from the test cup after the test. A.6 Heating plate support
. Any suitable support that can hold the heating plate horizontally and firmly can be used. 339
Additional instructions:
Immersion depth
Fine scale
Sub-scale
Digital scale
Scale error does not exceed
Expansion chamber, allowing heating to
Distance from the bottom of the ball to the 0℃ scale
Distance from the bottom of the ball to the 400℃ scale
GB/T 3536--83
Appendix B
Specifications of Thermometers
(Supplement)
6～400℃
25mm
1℃ (to 260℃)
2℃ (over 260℃)
420℃
310±5mm
6～7mm
7.5~10.0mm
4.5~6.0mm
45+10mm
275±10mm
This standard was proposed by the Ministry of Petroleum Industry of the People's Republic of China and is under the jurisdiction of the Petroleum and Chemical Industry Research Institute. The Petroleum and Chemical Industry Research Institute is responsible for drafting this standard.
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