Residence time refers to the time the material stays in the reactor, which is an important parameter affecting the reaction effect of the reactor. The length of residence time will affect the progress of the reaction, which in turn affects the efficiency and quality of chemical production.

　　First, the residence time influencing factors

　　1, the size of the volume of the reactor, the smaller the volume, the shorter the residence time.

　　2, the physical and chemical properties of the material, such as density, viscosity and rheology, etc. also have a certain impact on the residence time, the residence time of different materials may have a greater difference; 3, the stirring intensity of the reactor, the reaction time is not the same as that of the reaction kettle.

　　3, the stirring intensity of the reactor, the greater the intensity of the residence time is shorter;

　　4, reaction temperature and other reaction conditions such as control will affect the residence time.

　　Second, residence time calculation method

　　The key to the calculation of the residence time of the reactor is to determine the theoretical volume, the theoretical volume refers to the reactor in the maximum capacity of the volume of the reactants. Calculation formula for residence time is as follows:

　　Dwell time = theoretical volume / feed flow rate

　　Among them, the theoretical volume = net volume of the reactor × filling factor

　　The coefficient is generally taken between 0.7 and 0.8, taking into account the material bubbling, level meter error, etc. Some special material coefficients can only be taken to 0.5, for example, some of the reaction process has a gas generation to remove the reaction, the need for a larger de-volatilization space.

　　Assuming that the net volume of the reactor is 1m³, the coefficient is 0.75, the feed flow rate is 0.1m³/h, the residence time is:

　　Residence time = 1 x 0.75/0.1 = 7.5h

　　It should be noted that the calculation of residence time is a theoretical prediction, the actual production may be due to uneven flow of materials, emissions and other phenomena leading to changes in residence time.

　　Third, the measures affecting the residence time

　　In order to ensure the production efficiency and quality of the reactor, the following measures need to be taken:

　　1, in the procurement of reaction kettle, according to the actual production needs to choose the appropriate volume;.

　　2, regularly check the physical and chemical parameters in the reaction kettle to ensure the accuracy of the material;.

　　3, according to the nature of the reactants to determine the appropriate mixing intensity, to ensure that the material is fully mixed;

　　4、According to the laboratory test results to determine the appropriate reaction temperature and reaction conditions.

　　5、Regular maintenance of the reactor to ensure the normal operation of the equipment.

　　6、Increase the baffle folding back in the reactor, which can prolong the residence time of the material in the reactor.

　　7、Can control the residence time by adjusting the material level, such as raising the liquid level, can extend the residence time.

　　8, can be adjusted through the outlet valve opening, improve or reduce the material flow to control the residence time.

　　This article introduces the reactor residence time calculation method and residence time of the factors affecting, at the same time explains how to take measures to ensure that the reactor production efficiency and quality.

　　In the actual production, should be based on different reactants and reaction conditions for specific situation analysis, accurate calculation of residence time to ensure the realization of the reaction effect.