On the memory effect of vanadium catalysts
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This post was last edited by Zhang Ruqing on 2015-12-2 at 13:52. I’m a beginner in acid production processes. . The experts told me that vanadium catalysts have memory; in other words, when the vehicle is operated at a temperature of 400 degrees, the catalyst remembers this temperature. Later, when the vehicle is used again or exposed to exhaust gases, it will only start to react once the temperature reaches 400 degrees again. I was puzzled, so I researched a lot; basically, it is pressure and temperature that influence the reaction efficiency of catalysts, while there’s little information regarding memory effects. I’m seeking help. . What does this mean, expert?
The so-called memory effect means that the temperature at which the catalyst is used can only increase from low to high; once the starting temperature for using the catalyst is set high, it can only be higher thereafter, not lower. Low-temperature catalysts can be transferred to the high-temperature section, while those designed for high temperatures cannot be used in low-temperature conditions
The memory temperature response refers to the situation where your system operates at this conversion temperature for an extended period of time. . . . . .
I agree with your view. Poster: If the system is operating properly, the temperature of the catalyst is 400 degrees; it’s better to keep the system running at above 400 degrees in the future. It’s not necessary to reach exactly 400 degrees for a reaction to occur.
The memory effect observed in vanadium catalysts is, in my opinion, an intuitive manifestation of how temperature affects the diffusion processes within the molten system throughout the entire reaction process. One of the factors affecting catalyst activity is the structure of the carrier. During production, the catalyst undergoes a calcination process at temperatures above 500 degrees, and this process has an impact on the catalyst’s structure. This process is repeated to some extent during the heating up phase of operation. Different temperatures have varying effects on fixing the catalyst’s structure; for example, operating the system at a certain temperature for an extended period will inevitably have a certain effect on fixing the catalyst’s structure ； Furthermore, the effective catalytic components in the entire system undergo irreversible degradation over time and under varying operating conditions; to improve the catalytic efficiency, it is necessary to raise the reaction temperature, which involves altering the catalyst’s structure and increasing the activation energy of the reaction in order to meet the requirements. It is time to replace the catalyst when the temperature remains above its maximum allowable reaction temperature for an extended period.
The analysis by professionals makes sense. Based on our experience, catalysts of different types as well as those produced by various manufacturers have different ignition and reaction temperatures. The optimal control temperature determined for different systems can be adjusted, but it is beneficial to keep it relatively stable, as this is advantageous both for the catalysts and for production control.
It’s not a memory; it’s just a figurative way of expressing things. All catalysts have a temperature at which the reaction begins, and for sulfuric acid catalysts, this temperature gradually increases