What are the requirements for the use of industrial catalysts

　　What are the requirements for the use of industrial catalysts

　　One indicator is activity, which is also an important indicator for catalysts. It reflects the ability of industrial catalysts to promote the conversion of raw materials under simulated laboratory conditions. It is usually measured in moles per gram per hour, which represents the amount of reactant converted per unit mass of catalyst per unit time.

　　However, in specific application scenarios, its indicators may undergo slight changes. For instance, in the evaluation of catalytic reforming catalyst activity, the indicator may be represented by the yield of aromatic hydrocarbons obtained after the catalytic reforming of straight-run naphtha.

　　Another indicator is selectivity, which evaluates how much of the raw material can be converted into the target product during the catalyst-promoted reaction process. For example, in the process of cracking light oil or heavy oil, there may be many product outcomes such as gasoline, dry gas, coke, etc. As the main product, the yield of gasoline is naturally the higher the better. The proportion of gasoline in the total output is the selectivity of the gasoline product.

　　3. Lifespan or stability. It should be noted that in industrial production, the preparation of products often involves 24-hour non-stop operation. For example, in traditional coal processing workshops, workers usually adopt a two-shift or three-shift system. The power loss caused by downtime and the interruption loss of the production line are significant. In the catalytic process, the stability of the catalyst is particularly important. Generally, the stability of industrial catalysts often requires more than a thousand hours. The lifespan is generally expressed in hours. Some links also use the amount of catalyst consumed to process quality products as an indicator.

　　4. Shape and size. Depending on the reactor used in the catalytic process, catalysts come in various shapes and sizes. At the same time, differences in shape can lead to significant changes in performance. This is because they may affect the diffusion of reactants or products, thereby influencing their yield or selectivity. Depending on different usage conditions, catalysts can be shaped into various forms for use. For example, catalysts used in moving bed catalytic cracking units are generally in the form of small spheres, which facilitate the movement of catalysts within the reactor and ease their transportation, reducing wear and tear-related losses.

　　5. Mechanical strength. In addition to the aforementioned requirements, the mechanical strength of the catalyst is also an important indicator. Given that chemical reactions often occur under high temperature and high pressure conditions, it is naturally required that the catalyst withstand sufficient self-weight and external pressure. At the same time, it must also withstand the wear that may result from collisions between different catalysts, indicating a high resistance to wear.

　　6. Chemical composition. Chemical composition refers to the structural information of the catalyst, which serves as the foundation for the aforementioned reaction performance. The ratio and structure of different components directly affect the efficiency of the reaction.

　　7. Specific surface area and pore volume. The larger the specific surface area and pore volume, the more contact there will be between the reactants and the catalyst, which undoubtedly leads to better performance.

　　In summary, a good industrial catalyst must not only possess excellent activity, selectivity, and lifespan, but also meet requirements regarding shape, particle size and distribution, mechanical strength, as well as specific chemical composition and pore structure. Therefore, catalyst design is crucial, complex, and a process with high added value.