对于空塔另一个显著特点是易发生轴向逆向混合,随着氧化反应的不断进行,氧

Another significant feature of the empty tower is that it is easy to cause axial and reverse mixing. With the continuous progress of the oxidation reaction, the concentration of hydrogen peroxide in the oxidizing liquid continues to increase. Since the liquid and gas phase flow upwards, the higher the peroxidation The higher the hydrogen concentration, the more severe the difference between the upper and lower components. For ordinary empty towers, due to the axial molecular diffusion and turbulent diffusion and the natural convection caused by the weight difference of the upper and lower components, the axial reverse mixing is bound to occur, that is, the hydrogen peroxide enters the tower and the product hydrogen peroxide is oxidized. Liquid mixing. The result of this mixing is detrimental to the overall reaction. First of all, the oxidizing solution containing hydrogen peroxide is diluted to the concentration of the hydrogenation solution that has just entered the tower, and the reaction speed of reaction formula (2) is reduced.Due to the backmixing of the oxidizing solution containing hydrogen peroxide, under the condition of constant reaction volume Increase the throughput per unit time, thereby reducing the residence time of the hydrogenation liquid in the tower, so that a small part of the tetrahydro2-ethylhydroanthraquinone (THEAHQ) can not react and enter the post-processing system. Secondly, the oxidizing liquid that generates hydrogen peroxide is mixed in the reverse direction in the tower and enters the lower part. Because the degraded products at the bottom of the tower are denser, the degree of decomposition of hydrogen peroxide will inevitably increase, thereby reducing the oxidation yield.

Another notable feature of the empty tower is that it is prone to axial reverse mixing, with the continuous oxidation reaction, the concentration of hydrogen peroxide in the oxidation fluid is increasing, because the liquid phase and gas phase and flow up, so the higher the concentration of hydrogen peroxide, forming a difference in the weight of the upper and lower components. For ordinary empty towers, natural convection caused by axial molecular diffusion and turbulence diffusion, as well as the difference in the weight of the upper and lower components, is bound to occur axial reverse mixing, that is, hydrogenation fluid into the tower and hydrogen peroxide oxide mixture that has produced the product. The result of this mix is not conducive to the overall reaction. First of all, the hydrogen peroxide-containing oxidation liquid diluted the hydrogenation liquid concentration just entered the tower, reduced the reaction speed of reactive formula (2), because of hydrogen peroxide-containing oxidation liquid remix, in the reaction volume unchanged conditions increased the circulation of unit time, thus reducing the stay time of the hydrogen in the tower, so that a small number of tetrahydro-ethyl hydroxyquine (THEAHQ) can not react and enter the post-treatment system. Secondly, the hydrogen peroxide-producing oxidation fluid is mixed in reverse in the tower and enters the lower part, because the stronger degradation of the bottom of the tower will inevitably increase the decomposition of hydrogen peroxide and thus reduce the oxidation yield.

Another remarkable feature of the empty tower is that it is easy to mix in axial direction. With the continuous oxidation reaction, the concentration of hydrogen peroxide in the oxidation liquid increases continuously. Because the liquid phase and gas phase flow upward, the higher the concentration of hydrogen peroxide is, the worse the weight of the upper and lower components is formed. For the ordinary empty tower, due to the axial molecular diffusion and turbulent diffusion and the natural convection caused by the heavy difference between the upper and lower components, axial reverse mixing is inevitable, that is, the hydrogen liquor entering the tower and the oxidation liquid of hydrogen peroxide which has been produced will be mixed. The result of this mixing is not good for the whole reaction. Firstly, the concentration of hydrogenated liquid just entering the tower is diluted by the oxidation solution containing hydrogen peroxide, and the reaction speed of reaction formula (2) is reduced. Because of the back mixing of the oxidation solution containing hydrogen peroxide, the flow volume of unit time is increased under the condition of constant reaction volume, thus reducing the retention time of hydrogenated liquid in the tower, This makes a small part of tetrahydro2-ethylhydroanthraquinone (theahq) unable to react and enter the post-treatment system. Secondly, the oxidation liquid which produced hydrogen peroxide is mixed in the tower and enters the lower part. Because the concentration of the degradation at the bottom of the tower increases the decomposition degree of hydrogen peroxide, the oxidation yield is reduced.<br>