Activated alumina is a porous, highly dispersed solid material with a large specific surface area, uniform high and low temperature activity, good water resistance, and the active components and chlorine after the reaction are not easy to migrate. It has important applications in the field of dechlorination.
Dechlorination Principle
Activated alumina has a large specific surface area and rich pore structure. Chlorine and its compounds can be adsorbed on its surface by physical adsorption and chemical adsorption, such as hydrogen chloride. The hydroxyl groups on the surface of some activated alumina ball can react chemically with hydrogen chloride to generate corresponding aluminum salts and other substances, thereby achieving the purpose of dechlorination. For example, the hydroxyl groups (-OH) on its surface can react with hydrogen chloride (HCl), H+ combines with -OH to generate water, and Cl- combines with aluminum ions on the surface of activated alumina to achieve the effect of dechlorination.
Application Field
Petrochemical industry: During the oil refining process, the chlorine contained in crude oil will have a serious corrosive effect on subsequent processing equipment and processes. For example, in the atmospheric and vacuum distillation unit, chlorine will corrode pipelines, towers and other equipment, shortening the service life of the equipment. By using activated alumina as a dechlorinating agent, chlorine in oil products can be effectively removed, equipment can be protected from safe operation, and product quality can be improved.
Natural gas purification: If natural gas contains chlorine, it will not only corrode the transmission pipeline and equipment, but also affect the subsequent processing and utilization of natural gas. Activated alumina can be used for dechlorination of natural gas to ensure that the quality of natural gas meets relevant standards.
Other industrial gas purification: Gases produced in some industrial production processes, such as hydrogen, nitrogen, ammonia, carbon monoxide, carbon dioxide, etc., may contain a small amount of chlorine impurities. Using activated alumina for dechlorination treatment can make these gases reach higher purity requirements and meet the needs of production processes.
Factors Affecting Dechlorination Effect
Properties of activated alumina: Its specific surface area, pore volume, pore size distribution, and surface chemical properties will have a significant impact on the dechlorination effect. Generally speaking, the larger the specific surface area, the larger the pore volume, and the more reasonable the pore size distribution of activated alumina, the better its dechlorination performance.
Operating conditions: including temperature, pressure, gas flow rate, and contact time. Within a certain range, properly increasing the temperature can speed up the adsorption and reaction rate, but too high a temperature may cause changes in the structure of activated alumina adsorbent and reduce its adsorption performance. Too fast a gas flow rate will reduce the contact time between the gas and activated alumina, which is not conducive to the improvement of the dechlorination effect.
The content and form of chlorine in the raw gas: The higher the chlorine content in the raw gas, the higher the adsorption capacity requirement for activated alumina. At the same time, the existence form of chlorine (such as HCl, organic chlorine, etc.) will also affect the dechlorination effect. The reaction activity and adsorption capacity of different forms of chlorine with activated alumina are different.
In order to ensure that the activated alumina maintains good performance during the dechlorination process, it is necessary to regularly evaluate its performance and regenerate it. When the adsorption capacity of activated alumina reaches saturation, it can be regenerated by appropriate methods, such as heating, purging, etc., to restore its dechlorination capacity and extend its service life.
