Because alumina has high strength and large surface area, it is insoluble in water and organic solvents such as aromatics and lipids. It is odorless, odorless, and non-toxic. It has a strong ability to reduce and regenerate anthraquinone degradants, so it is currently used by most domestic hydrogen peroxide plants.

Because alumina has high strength and large surface area, it is insoluble in water and organic solvents such as aromatics and lipids. It is odorless, odorless, and non-toxic. It has a strong ability to reduce and regenerate anthraquinone degradants, so it is currently used by most domestic hydrogen peroxide plants.In the hydrogen peroxide production process, alumina plays two main roles: one is to regenerate the degraded substances generated by the working fluid in the hydrogenation process and the oxidation process, increase the effective anthraquinone content in the working fluid, and stabilize the components of the working fluid; the second is to adsorb a small amount of lye entrained in the working fluid in the post-treatment process to avoid poisoning of the palladium catalyst due to the high alkalinity in the working fluid and cause oxidation and hydrogen peroxide decomposition in the extraction process. When the activated alumina loses its ability to regenerate the degraded substances in the working fluid, it cannot continue to regenerate the degraded substances in the working fluid; when the activated alumina adsorbs the lye in the working fluid and reaches a saturated state, it cannot continue to adsorb the lye in the working fluid. At this time, the activated alumina should be replaced in time.Overdue use of activated alumina will have the following effects on the system: 1) The alkalinity of the working fluid exceeds the standard, poisoning the palladium hydride catalyst, reducing the hydrogenation efficiency, and increasing the consumption of the catalyst. At the same time, it causes oxidation of the working fluid and hydrogen peroxide decomposition in the extraction process.2) The degraded substances in the working fluid continue to increase, and the content of anthraquinone continues to decrease, which leads to an increase in anthraquinone consumption, a decrease in production, and a decrease in quality.3) As the degraded substances accumulate in the system, the viscosity of the working fluid greatly increases, which can easily cause the liquid in the extraction tower and the large amount of alkali in the drying tower, endangering the safety of the system.

Combined with the characteristics of the equipment in this workshop, there are the following suggestions on how to extend the service cycle of activated alumina：

1) Strictly control the specific gravity of alkali in the drying tower. The role of lye is to absorb moisture and acid in the working fluid, decompose hydrogen peroxide, and regenerate degraded substances.In general production, the specific gravity of the alkali in the drying tower is 1.3-1.4mg/L. When the specific gravity of the alkali is too low, the drying tower cannot give full play to its role in absorbing moisture and decomposing hydrogen peroxide. The water and hydrogen peroxide enter the clay bed to reduce the regenerative capacity of activated alumina and shorten its life; when the specific gravity of the alkali is too high, the viscosity of the alkali concentration is too high, causing the working fluid to be alkaline and reduce the activity of alumina.

2) Control the flow of working fluid into the bed. At present, there is a lack of flow meters at the inlet of each white land bed. Due to the different resistance in the bed, the flow rate of each bed may be different, resulting in uneven distribution of each white land bed, which affects the use effect.Installing a flowmeter at the inlet of the bed will effectively solve this problem.

3) The position difference between the alkali separator of the hydrogen peroxide device in the workshop and the clay bed is large, which is likely to cause the phenomenon of siphon gas. The gas agitates in the clay bed, causing friction between the alumina and producing dust. At the same time, because the air occupies part of the space, it affects the full contact between the working fluid and the alumina, thereby reducing the regeneration effect.Controlling the opening of the inlet valves of each bed of the clay bed, closing the vent valve of the clay bed so that a certain pressure is generated in the bed can effectively reduce the phenomenon of air, thereby improving the use effect of activated alumina.

4) Avoid the residual extraction liquid with water. If the residual extraction liquid is in large quantities with water, the alkali solution in the drying tower will be diluted, which will reduce the alkali concentration and cause the working fluid to bring water and alkali into the clay bed, causing the activated alumina to fail and shorten the service cycle.

5) Strictly control the content of hydrogen peroxide in the extracted liquid. If the content of hydrogen peroxide in the extracted liquid is too high, the hydrogen peroxide decomposes after the working liquid enters the drying tower and produces a large number of air bubbles, causing the working liquid to flow out of the drying tower with alkali. After the alkali separator, the lye may still not be separated and enter the clay bed, shortening the service cycle of activated alumina.

6) When the system is equipped with a large flow rate, even if the working fluid condition is poor, the phenomenon of alkali in the drying tower has not occurred, but in the process of replenishing the system, the working metering tank may bring air into the drying tower or the flow rate is too large to cause the drying tower to be alkaline. Suspend the replenishment of the working fluid and reduce the flow of the working fluid of the system in time and increase the level of the working fluid metering tank can solve the problem and prevent a large amount of alkali from entering the clay bed; try to control the smaller flow rate and slowly add it every time you replenish the working fluid to the system.

7) According to the analysis results of the working fluid components, appropriately adjust the working fluid flow of each clay bed, so as to maximize the capacity of each clay bed without affecting production, and improve the efficiency of the use of activated alumina, thereby improving the service cycle of activated alumina; of course, according to the production conditions, the activated alumina should be replaced in time when it fails, so as not to affect normal production.