GB/T 3069.2-1986 Determination of naphthalene crystallization point GB/T3069.2-1986 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Method for the determination ofthe crystallization temperature of naphthaleneUDC668.736.3
GB 3069.2-86
Chemical Forest GH 3069,2-82
This standard is applicable to the determination of the crystallization temperature of naphthalene in the naphthalene-containing fraction obtained by fractionation of high-temperature coal tar, refined naphthalene, low-grade naphthalene and pressed naphthalene obtained by washing, rectification and pressing.
1 Test Principle
When the liquid is cooled to a certain temperature, a precipitate is precipitated, and the highest point reached by the temperature is the crystallization point of naphthalene. 2 Sample Collection and Preparation
Solid naphthalene shall be sampled in accordance with GB2000-80- "Sampling Method for Solid Coking Products", and liquid naphthalene shall be sampled in accordance with GB2289--80 "Sampling Method for Viscous Oil Coking Products". Finally, the sample obtained by the reduction is ground into powder with a mortar. 3 Instruments
3.1 The tester for the product point is shown below.
40 ± 1
Medium 15 ±
Engraved
The tester for the product point
National Bureau of Standards 1986-08-13 IssuedbzxZ.net
Φ22±1
1987-08-01 Implementation
GB a069.2--86
3.2 Precision thermometer: temperature range 70～90C, sub-scale 0.1℃, total length 300mm, fully immersed 3.3 Thermometer, temperature range (～100℃, scale 1℃. 3.4 Melting test tube: diameter 35±1mm, 10:3mm 3.5 Stopwatch.
3.6 Water: can maintain temperature 85~90℃. 3.7 Slow cooker: general type, can maintain 90±5C. 4 Reagents
4.1 4A sieve: 60~81℃, calcine in 450~500℃ furnace for 2h, store in + desiccator. 4.2 Copper sulfate with hydrate: chemical.
5 Test steps
5.1 Take 30~40g of sample and put it into melting test tube, add 4A sieve or 2g of anhydrous copper sulfate, cover, place the test tube in a constant temperature water bath at 85~90℃, after the sample is melted, mix carefully and stay in the constant temperature water bath for not less than 5min. 5.2 Melt Pour the clear liquid into the cumulative point measuring instrument preheated to 90℃ quickly to the scale line, and then tighten the plug of the precision thermometer which has been preheated to 85℃. The precision thermometer is attached with a thermometer (3.3) next to it. Make sure that the precision thermometer is located at the center line of the instrument, and the bottom of the mercury ball is 20mm from the bottom of the cumulative point measuring instrument. 5.3 Slowly shake the measuring instrument to avoid violent vibration. Repeat the temperature every half minute. The temperature gradually decreases. When the temperature starts to rise, the temperature is stopped. When it reaches the highest point and stays for more than 1 minute, the temperature is the cumulative point. Read and record this temperature and humidity. The reading is estimated to be 1.01℃. At the same time, record the humidity in the middle of the mercury exposed part of the precision thermometer. If the temperature rises during the delay measurement or the time it rises to the highest humidity is less than 1 minute, the test must be repeated. 5. 4. Calculation of test results
Observed reading temperature is compensated according to the formula (!): t = t. + At++at2
Wherein - the crystallization point of naphthalene, C;
l - the observed temperature of the crystallization point of naphthalene,,,
At, the calibration value of the precision thermometer, calibrated according to the calibration book, C; A12 - the temperature calibration value of the mercury exposed part of the hygrometer. A12 is calculated according to the formula (2):
Atg=n.000161 (tu-tm)
Formula: H is the height of the mercury column on the exposed part of the precision thermometer on the cork, expressed in degrees; H is the temperature of the thermometer near the middle of the mercury column on the exposed part of the precision thermometer, (6 Precision
Repeatability r: not more than u.05℃.
Additional remarks:
This standard was proposed by the Ministry of Metallurgy of the People's Republic of China. This standard was initiated by Shandong Iron and Steel Corporation and Shandong Thermal Energy Research Institute. The main drafters of this standard are Yin Xiaolai, Sun Guiyi and Guo Xiuqian. From the date of implementation of the Japanese standard, the former Ministry of Metallurgical Industry Standard YB292-75 "Mu" will be abolished. (1)
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