Automatic determination of benzene crystallization point solution
The detection of benzene crystallization point is a characteristic index of purity test of general industrial products.
In the low temperature cooling process, the pure liquid may appear too cold state, namely when at or below the temperature of crystallization point, the material is still in a liquid state without precipitation crystallization to coagulation state, the main reason is due to the static in the liquid, no enough seed formation, although reach even below the crystallization temperature at this moment, but not in crystallization. When there is proper agitation in the system, enough seeds appear to promote crystallization with the cooling process.
Therefore, when determining the crystallization point of benzene, it will be specified in the operation process that the cooling operation is carried out, and at the same time, the liquid of the benzene sample is appropriately stirred. Without stirring, the measurements will be low, and abnormal temperature increases may occur during the measurement process.
Standard GB/T3145-1982 determination of benzene crystallization point, GB/T 3069.2-2005 determination of naphthalene crystallization point, GB/T 3710-2009 determination of industrial phenol, phenol crystallization point, Determination of crystallization point of organic chemical products and determination of crystallization point of chemical reagents GB/T7533-1993-2005 Determination of crystallization point of plasticizer. (Benzene crystallization point meter, phenol crystallization point meter, phenol crystallization point meter, freezing point meter, plasticizer crystallization point meter)
Instrument features: using embedded system design, automatic testing of the whole process; Adopt imported PT100 sensor and imported temperature control system. Color touch screen; The test results can be stored; You can view historical data; The results can be printed on the instrument and automatically stirred by the machine. The experimental results can be exported through the U disk and stored in the computer for many times.
Instrument for experiment
1.SH406B automatic measuring instrument for benzene crystallization point, shandong Shengtai Instrument Co., LTD.
2. Comply with GB/T3145.
Experimental steps:
First, preparation
1. After unpacking the instrument, please check the accessories according to the packing list. If there is any damage, please contact our company.
2, the instrument should be carried vertically, tilt Angle along the height of the instrument swing Angle is not more than 30 degrees, placed in the dark place, place to be stable, otherwise there will be vibration after the instrument starts, affecting the service life of the instrument.
3, the instrument power supply is received in the capacity of 220V/10A above the socket, pay attention to must have a good grounding wire.
Second, the experiment process
1. After unpacking the instrument, please check the accessories according to the packing list. If there is any damage, please contact our company.
2, the instrument should be carried vertically, tilt Angle along the height of the instrument swing Angle is not more than 30 degrees, placed in the dark place, place to be stable, otherwise there will be vibration after the instrument starts, affecting the service life of the instrument.
3, before starting up (to add alcohol for the first time) check the alcohol level in the cold bath, to ensure that the alcohol level should exceed the level of the refrigeration circuit and sample in the cold bath, when alcohol is insufficient, be sure to add enough alcohol first, and then conduct the experiment.
4, the instrument power supply is received in the capacity of 220V/10A above the socket, pay attention to must have a good grounding wire.
5. Take out the sample and put it into a clean and dry cooling tube.
6. Place the cooling tube in the coolant and tighten the cork.
7. Adjust the appropriate position of the tube stirrer to make the sensor in the center of the stirrer circle.
8. Turn on the power and click the touch screen to enter the main control interface.
The main display area is the temperature trend diagram of the sample with time, which can show the temperature value of the sample and ice bath. The display area on the right will show the specific value, and the expected crystallization point and experimental results of the test tube are below. The lower right corner is the test start button and close button.
On the parameter setting interface, you can set the date and time to calibrate the sample temperature and bath temperature. And the sample number can be set. If you modify these parameters, click the time number and click the long box, the virtual keypad will appear to complete the number modification.
The expected crystallization point is related to the experimental process. The instrument detects the crystallization point from 15° above the expected crystallization point, and records it every 15S until the crystallization point is detected. If the crystallization point has not been detected to the expected crystallization point, the instrument can be extended to 30 degrees below the expected crystallization point to continue the detection, giving a large range for the convenience of the user. Bath temperature control is also related to the desired crystallization point (out of range bath heating)