A device and method for measuring the freezing point of Fischer-Tropsch wax and petroleum wax

Abstract

A device and method for determining the freezing point of Fischer-Tropsch wax and petroleum wax, the device comprising: a freezing point thermometer, a transparent air bath device, a rotating device and a heating device, the transparent air bath device having a plug, the freezing point thermometer being mounted on the central axis of the plug, the rotating device being provided with a support seat, the heating device being used to heat the transparent air bath device, wherein the heating device is a hot air gun or an infrared heater. The determination method comprises: melting the sample into a liquid; dipping the sample with the freezing point thermometer; mounting the freezing point thermometer with the liquid sample on the transparent air bath device; heating the transparent air bath device rotating on the rotating device, controlling the heating intensity, stopping heating when the thermometer reaches a specified temperature, observing the wax sample and the thermometer reading on the mercury ball, and immediately reading the temperature value when the wax sample rotates with the mercury ball of the thermometer, which is the freezing point of the sample. The device of the present invention has low cost, simple and convenient operation, and high accuracy of the result.

Description

Technical Field

[0001] The invention belongs to the field of sample freezing point testing, and in particular relates to a device and a method for determining the freezing points of Fischer-Tropsch wax and petroleum wax. Background Art

[0002] The temperature at which the melted sample stops flowing after being cooled under specified conditions is the freezing point of the sample. Fischer-Tropsch wax and petroleum wax may be solid or nearly solid, or semi-solid at this temperature, which is related to the composition of the sample being tested. In the case of petrolatum, the freezing point is related to the gel structure of the sample when it is cooled. It is an indicator that indirectly reflects the average molecular weight and purity of wax products and the degree of hardness and softness at room temperature, which can reflect the safety and difficulty of storage, processing and transportation. Domestic research and development of special waxes, especially research and development using Fischer-Tropsch wax as raw materials, focuses on melting point, dropping point and drop melting point, while foreign special wax manufacturers and users are more interested in and pay more attention to the freezing point indicator. Represented by South Africa's Sasol, almost all of its special waxes such as hot melt adhesives, inks / paints, plastics, rubber, polishes, textiles, crayons, candles, and beauty cosmetics have listed the freezing point as an important indicator. In China, a Shanxi company has used the freezing point as the product label. It can be expected that people will gradually realize the importance of the freezing point for special waxes in the future, and more and more manufacturers will regard the freezing point as one of the important quality indicators of their products.

[0003] The existing technology has the disadvantages of inconvenient manual operation, high technical requirements for operators, more equipment required to complete the analysis and testing, large equipment investment, and long analysis time, as follows:

[0004] 1. The equipment investment cost is relatively high. In addition to purchasing a freezing point thermometer, a conical flask and a speed regulating rotating device, a constant temperature oven is also required, which occupies a large area of ​​the laboratory table, about 2 meters long;

[0005] 2. The actual operation has many steps, a long process, and takes a long time. In addition to preparation, the whole process mainly includes 6 processes, and the total time required is about 2 hours depending on the sample;

[0006] 3. The operating conditions are difficult to grasp. You need to protect your hands with a towel or gloves. It is easy to get burned and the operation is very difficult. Summary of the invention

[0007] The present invention aims to simplify the freezing point analysis operation process of Fischer-Tropsch wax and petroleum wax including their fractions and residual wax (including vaseline), shorten the analysis time, and find a faster and more accurate freezing point analysis method which is safer, simpler and easier to operate.

[0008] The device for determining the freezing point of Fischer-Tropsch wax and petroleum wax of the present invention comprises: a freezing point thermometer, a transparent air bath device, a rotating device and a heating device, wherein the transparent air bath device has a plug, the outer edge of the plug is provided with an air guide groove, the freezing point thermometer is installed on the central axis of the plug, a support seat is arranged on the horizontal rotating shaft of the rotating device, the transparent air bath device is fixed on the support seat, the heating device is used to heat the transparent air bath device, and the heating device is a hot air gun or an infrared heater. The transparent air bath device can be a container such as a flask.

[0009] Preferably, the rotating device is a small speed-regulating motor.

[0010] Preferably, the axis center of the horizontal rotating shaft coincides with the symmetry axis of the transparent air bath device.

[0011] Preferably, the distance from the bottom of the mercury ball of the freezing point thermometer to the bottom of the transparent air bath device is about 10 to 15 mm.

[0012] Preferably, the transparent air bath device is fixed on the support seat by a magnetic sheet.

[0013] The method for determining the freezing point of Fischer-Tropsch wax and petroleum wax of the present invention comprises:

[0014] (1) Melt the sample into liquid;

[0015] (2) Dip the sample using a freezing point thermometer;

[0016] (3) Installing a freezing point thermometer with a liquid sample on a transparent air bath device;

[0017] (4) Heat the transparent air bath device rotating on the rotating device and control the heating intensity. When the thermometer reaches the specified temperature, stop heating and observe the wax sample on the mercury ball and the thermometer reading. When the wax sample rotates with the mercury ball of the thermometer, read the temperature value immediately, which is the freezing point of the sample.

[0018] Preferably, the sample is melted into a liquid and then stirred thoroughly.

[0019] Preferably, when dipping the sample, the liquid sample is made to adhere to the mercury ball of the thermometer.

[0020] Preferably, the rotation speed of the rotating device is 2 to 3 s / revolution.

[0021] Preferably, the same sample is measured repeatedly, and the average value of 2-3 measured values ​​is taken as the freezing point of the tested sample.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The heating equipment can be a closed electric furnace and a hot air gun, which are small in size and low in price. Due to the ingenious design of the operation mode, the requirements for equipment performance are reduced, and the equipment purchase cost and the area occupied by the laboratory bench are reduced by more than half;

[0024] 2. Simplified the process, improved the efficiency of analysis and testing, organically combined the sample dipping, component installation and preheating process, and adopted the method of first dipping the sample, then installing the components and finally heating to achieve the purpose of convenience and safety. Including sample preparation, the time used for the whole process can be shortened from 1.5 hours to about 0.5 hours;

[0025] 3. Easy to operate. You only need to control the heating intensity of the hot air gun or infrared heater to control the heating speed, and it is easy to meet the temperature requirements.

[0026] 4. The results are highly accurate. The repeatability and reproducibility of Fischer-Tropsch wax are ≤0.5℃ and ≤1.5℃ respectively; the repeatability and reproducibility of residual wax (including vaseline) are ≤1℃ and ≤2.5℃ respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a measuring device in an embodiment of the present invention;

[0028] Figure 2 The present invention is a flow chart of the determination method.

[0029] 1-freezing point thermometer; 2-flask; 3-rotating device; 4-heating device; 5-stopper; 6-flask support base; 7-magnetic sheet. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0031] In the embodiment of the present invention, the Fischer-Tropsch wax sample is heated and melted in a closed electric furnace, and the mercury ball of the thermometer is used to dip the Fischer-Tropsch wax droplets, which are loaded into a conical flask as a jacket, and then horizontally mounted on a rotating device, and the flask is heated to melt the Fischer-Tropsch wax adhered to the mercury ball, and cooled at a rated speed until condensed. When the Fischer-Tropsch wax droplets stop flowing, the observed temperature is the solidification point. The present invention is applicable to the test of the solidification point of Fischer-Tropsch wax, including petroleum wax and vaseline.

[0032] like Figure 1As shown, the device for determining the freezing point of Fischer-Tropsch wax and petroleum wax of the present invention comprises: a freezing point thermometer 1, a flask 2, a rotating device 3 and a heating device 4, wherein the flask is provided with a stopper 5, the outer edge of the stopper 5 is provided with an air guide groove, the freezing point thermometer is mounted on the central axis of the stopper, a flask support seat 6 is arranged on the horizontal rotating shaft of the rotating device, the flask 2 is fixed on the flask support seat 6, and the heating device 4 is used to heat the flask 2. The heating device 4 can be a hot air gun or an infrared heater, etc., which can perform directional heating on the flask 2.

[0033] The rotating device 3 can be a small speed-adjustable motor with a speed adjustable to 2-3s / turn, and the axis of the horizontal rotating shaft coincides with the symmetry axis of the flask.

[0034] Flask 2 is used as a transparent air bath device of the thermometer and can be a conical flask with a volume of 125 mL.

[0035] The distance from the bottom of the mercury ball of the freezing point thermometer 1 to the bottom of the flask is about 10 to 15 mm.

[0036] The connection between the flask 2 and the rotating device 3 can be in various ways. For example, it can be magnetic connection, that is, a magnetic sheet 7 with a thickness of 2-3 mm and a diameter of 20-30 mm is glued to the bottom of the flask with heat-resistant glue, and then fixed to the flask support seat coaxial with the rotating device by magnetic force. Of course, in addition to this method, other methods of fixed connection can also be used.

[0037] like Figure 2 As shown, the method for determining the freezing point of Fischer-Tropsch wax and petroleum wax of the present invention comprises:

[0038] (1) Melt the sample into liquid;

[0039] (2) Dip the sample using a freezing point thermometer;

[0040] (3) Install a freezing point thermometer with a liquid sample on the flask;

[0041] (4) Heat the rotating flask on the rotating device and control the heating intensity. When the thermometer reaches the specified temperature, stop heating and observe the wax sample on the mercury ball and the thermometer reading. When the wax sample rotates with the mercury ball of the thermometer, read the temperature value immediately, which is the freezing point of the sample.

[0042] After the sample is melted into liquid, stir it thoroughly.

[0043] When dipping the sample, make the liquid sample stick to the mercury ball of the thermometer.

[0044] The rotation speed of the rotating device is 2 to 3 seconds per revolution.

[0045] Repeat the measurement on the same sample and take the average value of 2-3 measured values ​​as the freezing point of the tested sample.

[0046] Example 1

[0047] (1) Install the thermometer on the central axis of the stopper so that the bottom of the thermometer mercury bulb is about 10 to 15 mm from the bottom of the conical flask.

[0048] (2) Take 50 g of a representative sample, place it in a 100 ml glass beaker, and heat it to 11°C above the expected freezing point (make sure to stir it thoroughly).

[0049] (3) Use the thermometer installed on the stopper to dip a drop of sample, hold the thermometer horizontally and slowly rotate it several times to allow the sample to solidify evenly on the mercury ball, and then install it horizontally on the conical flask.

[0050] (4) Press the small speed regulator switch, adjust the speed to 2-3s / turn, and heat the conical flask with a heat gun until the mercury column of the thermometer reaches the 99±3℃ mark and stops rising. Remove the heat gun and observe the droplets on the mercury ball. When the droplets rotate with the mercury ball of the thermometer, immediately read the temperature of the thermometer with an accuracy of 0.5℃ and record this measured value. Repeat the measurement with the same sample and take the average of the two measured values ​​as the freezing point of the tested sample.

[0051] During the measurement, the average value of multiple test values ​​can be recorded as the freezing point, accurate to 0.25°C.

[0052] The measurement precision requirements are as follows:

[0053] Repeatability: The deviation of the final results obtained by the same operator using the same device to test the same sample under constant conditions. The requirements are as follows:

[0054] Fischer-Tropsch wax (including paraffin fraction) ≤ 0.5℃; residual wax (including vaseline) ≤ 1.0℃.

[0055] Reproducibility: The deviation of two independent results obtained by different laboratories and different operators on the same sample. The requirements are as follows:

[0056] Fischer-Tropsch wax (including paraffin fraction) ≤1.5℃; residual wax (including vaseline) ≤2.5℃.

[0057] The present invention adopts cold installation technology. After dipping a proper amount of sample with a thermometer, the assembly is installed at room temperature, replacing the installation method of preheating the conical flask to 99°C. The sample heating adopts rotary heating technology. When the test assembly rotates at a constant speed, a hot air gun or an infrared heater is used to heat the conical flask from the outside, replacing the heating method of a constant temperature oven, reducing equipment costs and simplifying the operation process.

[0058] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for determining the freezing point of Fischer-Tropsch wax and petroleum wax, comprising: (1) Melt the sample into liquid; (2) Dip the sample using a freezing point thermometer; (3) Install the freezing point thermometer with the liquid sample on the transparent air bath device; (4) Heat the transparent air bath device rotating on the rotating device and control the heating intensity. When the thermometer reaches the specified temperature, stop heating and observe the wax sample on the mercury ball and the thermometer reading. When the wax sample rotates with the mercury ball of the thermometer, read the temperature value immediately, which is the freezing point of the sample; The freezing point thermometer, the transparent air bath device, the rotating device and the heating device constitute a measuring device, the transparent air bath device is provided with a plug, the outer edge of the plug is provided with an air guide groove, the freezing point thermometer is installed on the central axis of the plug, the horizontal rotating shaft of the rotating device is provided with a support seat, the bottom of the transparent air bath device is fixed on the support seat, the heating device is used to heat the transparent air bath device, and the heating device is a hot air gun or an infrared heater; The axis of the horizontal rotating shaft coincides with the symmetry axis of the transparent air bath device, the distance between the bottom of the mercury ball of the freezing point thermometer and the bottom of the transparent air bath device is 10-15 mm, and the rotation speed of the rotating device is 2-3 s / revolution.

2. The measuring method according to claim 1, characterized in that The rotating device is a small speed regulating motor.

3. The measuring method according to claim 1, characterized in that The transparent air bath device is fixed on the supporting seat through a magnetic sheet.

4. The measuring method according to claim 1, characterized in that After the sample is melted into liquid, stir it thoroughly.

5. The measuring method according to claim 1, characterized in that When dipping the sample, make the liquid sample stick to the mercury ball of the thermometer.

6. The measuring method according to claim 1, characterized in that Repeat the measurement on the same sample and take the average value of 2-3 measured values ​​as the freezing point of the tested sample.

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