GB/T 510-2018Determination of solidification point for petroleum products (English PDF)

3.1 Solidification point

The highest temperature, at which the liquid level stops moving, when the sample is cooled, under specified conditions, expressed in °C.

5.2 Material

5.2.1 Coolant or material. Industrial ethanol, dry ice or liquid nitrogen, etc., OR any other liquid or material, which can cool the sample to the temperature, which is specified in the test. Compressor refrigeration or semiconductor refrigeration equipment can also be used.

5.2.2 Filter paper. Qualitative filter paper.

6.1 Manual solidification point tester

6.1.1 Test tube. Transparent glass test tube, with round bottom; the height is 160 mm ± 10 mm; the inner diameter is 20 mm ± 1 mm; there is a circular marking on the outer wall, 30 mm from the bottom of the test tube; there is a plug, which can be inserted into the thermometer.

6.1.4 Thermometer or temperature measuring device. The thermometer, which is used to measure the temperature of the specimen, shall meet the requirements of No.GB-30, No.GB-31 or No.GB-32 in GB/T 514-2005.

6.1.5 Bracket. It is used to fix test tubes, casings, thermometers.

6.2 Automatic micro-solidification point tester (only applicable to diesel fraction samples without additives)

6.2.1 Sample injection system. Manual sample injection or automatic sample injection, which may add a certain amount of specimen into the detection chamber.

6.2.2 Refrigeration system. Provide a cold source for the detection chamber, which has a temperature control accuracy of ±0.1 °C.

8.1 Sample preparation

8.1.1 Shake the specimen uniformly, before the start of test. However, for anhydrous specimen, it may start the test directly.

8.1.2 It may dehydrate the specimen, in accordance with the requirements of 8.1.3 or 8.1.4. However, for the specimen which has high moisture content, it shall stand, before taking the clear part for dehydration.

8.1.4 For viscous specimen, the dehydration treatment is to preheat the specimen to no more than 50 °C; then filter it through a salt layer.

8.2 Preparation of manual solidification point tester

8.2.1 When preparing a cooling bath, which contains dry ice, it may add absolute ethanol to a container of coolant; fill it to 2/3 of the depth of the container.

8.2.3 Vertically immerse the test tube, which contains specimen and thermometer, in a water bath at 50 °C ± 1 °C, to heat it, until the temperature of the specimen reaches 50 °C ± 1 °C.

8.3 Preparation of automatic micrometer

Prepare the instrument, in accordance with the requirements of the manual of the automatic micro solidification point tester.

9.1 Manual instrument

9.1.1 When the temperature of the specimen reaches 50 °C ± 1 °C, take out the test tube, which contains the specimen and thermometer, from the water bath. Wipe dry the outer wall of the test tube. Put the test tube firmly into the casing. It shall ensure that the distance between the outer wall of the test tube and the inner wall of the case is equal.

9.1.4 Carefully remove the casing and test tube assembly, from the cooling bath. Use absolute ethanol to quickly wipe the outer wall of the sleeve. Place it vertically. Observe, through the casing, whether the liquid level in the test tube shows signs of movement.

Note: When measuring the specimen, which has a solidification point lower than 0 °C, in order to facilitate observation, it may inject 1 mL ~ 2 mL of absolute ethanol, into the bottom of the casing, before the test.

9.1.5 When the position of the specimen liquid level moves, take out the test tube from the casing. Reheat the test tube, until the specimen reaches 50 °C ± 1 °C. Then use a temperature, which is 4 °C lower than the previous test temperature OR other lower temperature, to make measurement again, until a certain test temperature can stop the liquid level of the specimen from moving.

9.1.8 If it is necessary to check whether the solidification point of the specimen meets the specification value, the test shall be carried out, at 1 °C higher than the specification value. At this time, if the specimen liquid level can move, it is considered that, the solidification point of the specimen meets the specification value.

9.2 Automatic micrometer (only applicable to diesel distillate samples without additives)

9.2.1 Use manual sample injection or automatic sample injection, to take a certain amount of specimen. Select the appropriate test procedure, to start the test, according to the manual of the automatic micro-solidification point meter. A new sample shall be replaced, when repeating the test. […]