【Weekly Topic】Production Technology: Discussing how to use catalysts correctly during production processes (4.4~4.10)

First, select an appropriate catalyst; each catalyst has a different purpose； Secondly, it is necessary to be aware of the usage conditions or environment of the catalyst, such as acidity, alkalinity, temperature, pressure, as well as precautions for its use ； Another factor is the amount of catalyst used; too much or too little is not good ； Finally, attention should be paid to the method of adding the catalyst; an appropriate method will enhance its catalytic efficiency.

1. Strictly control the operating conditions and use reactors with a reasonable design. 2. Maintain the reaction temperature within the optimal range for the catalyst to prevent overheating. 3. Toxic impurities in the reaction materials should be removed in advance, ensuring that their concentration remains below the level tolerable by the catalyst. 4. In systems where carbon deposition occurs, reaction conditions that help prevent such deposition should be employed, along with catalysts that have high resistance to carbon deposition

The last edit to this post was made by Refinery Operator on 2011-4-4 at 18:33, with a reply to 2# cirulaiyuan: 1. First and foremost, fully consider the impact of process production capacity and intensity on the catalyst, and select an appropriate type of catalyst based on the characteristics of the reaction； 2. The loading and unloading of the catalyst should be done properly ； 3. Fully consider the impact of raw materials and reaction products throughout the production process on the catalyst, and promptly remove various toxic substances to prevent catalyst poisoning ； 4. Strictly control operating conditions to prevent the catalyst from overheating ； 5. When catalyst deactivation occurs, regeneration should be adjusted promptly

Let me talk about the catalysts used in our process. Our process represents a new technology in China’s polypropylene industry. There are three types of catalysts used in this process: the main catalyst (titanium tetrachloride), the co-catalyst (triethylaluminum), and the modifier (silane). All three of these catalysts are highly dangerous; in particular, the co-catalyst can explode when it comes into contact with water and can catch fire when exposed to air. It is therefore essential to pay close attention to the properties of these catalysts, and different handling methods should be adopted depending on their respective properties； 2. Modifiers can poison the catalyst; thus, for a given process in which multiple catalysts are present, their interactions must be taken into consideration ； 3. Catalysts and modifiers can form complexes, and these complexes have no toxic effect on the main catalyst; thus, it is important to consider the order in which catalysts are added ； 4. In the initial stage, the titanium ions in the main catalyst are in a +4 valence state; their +3 valence state is more reactive. Co-catalysts reduce them to the +3 valence state, which indicates that there is an interaction between catalysts, and this may lead to better results ；

1. Catalysts are delicate and prone to deactivation; it is necessary to control the amount of harmful impurities in the reaction system. 2. Determine the optimal conditions for using the catalyst, such as the required temperature and pressure. 3. When installing the catalyst, pay attention to its properties in order to prevent deactivation or a decrease in activity, as well as the introduction of impurities during installation and removal. 4. Ensure proper distribution of the catalyst within the reaction system in order to maximize its efficiency. 5. Some catalysts are toxic and harmful； Therefore, protective measures should be taken during operation, and the procedures must be followed strictly

Our factory is small, and the catalysts we use are simple as well, but there are still things to pay attention to. In my opinion, the activity of the catalyst has the greatest impact on product quality. 1. When regenerating the catalyst, it’s important to pay attention to the regeneration process. We use silver catalysts, which are regenerated through electrolysis; the crystal structure and quantity of silver during this process have a significant impact on production. 2. When filling the catalyst, attention must also be paid to its thickness and the ratio of different particle sizes. 3. During production, it’s crucial to eliminate all factors that could affect the catalyst’s activity, so as to maintain its optimal performance

Issues such as controlling the temperature of hot spots, controlling the heating rate, avoiding frequent start-up and shutdown, paying attention to catalyst loading and the heating and reduction (sulfidation) of catalysts, and operating under light load.

1. Select a catalyst suitable for production. 2. Control the temperature, pH value, and pressure according to the process requirements and dosage of the catalyst. 3. Adjust the amount of reactant added to prevent catalyst poisoning.

1. Choose it according to its purpose. 2. Follow its operating conditions strictly.

This post was last edited by shmily327 on 2011-4-5 23:11. Catalysts are the core of device reactions. If problems occur with the catalyst (such as reversible poisoning, irreversible poisoning, contamination, sintering, etc.), it can cause significant damage to the plant, even requiring shutdown for replacement. In my opinion, the use of catalysts in the production process can be considered from the following aspects: 1: Raw materials. All raw materials that enter the reaction system and come into contact with the catalyst must meet the requirements for using that catalyst. Keep impurities that are harmful to the catalyst within acceptable limits, and reduce the content of such harmful impurities as much as possible. 2: The operation should be smooth, with no significant fluctuations in response. Parameters such as temperature, pressure, and space velocity must be maintained stably; adjustments should be made gradually to avoid stressing the catalyst. 3: Temperature control. A reasonable temperature control range should be established by taking into account both selectivity and catalyst lifespan. 4: Use of additives – Some catalysts require the continuous addition of additives during use in order to improve yield or selectivity. Generally speaking, catalysts are quite sensitive to these additives. Therefore, the addition amount must be controlled very strictly; it should be determined by taking into account the reaction conditions, temperature, and the service life of the catalyst. 5: Emergency protection, in the event of severe fluctuations or other uncontrollable phenomena. Decisive measures should be taken to protect the catalyst. Furthermore, the selection and packing (fixed bed) of the catalyst play a very important role in its use. Since it falls outside the scope of process operations, it will not be discussed here. It's just my personal opinion; I welcome any criticism or suggestions.