How to control catalyst loss?

Hello, are you referring to the catalyst in the denitration system?

Does the catalyst in catalysis get worn out? It is generally divided into two types of losses: 1. Losses from the settler to the fractionator, and 2. Losses from the regenerator to the chimney. For solution to issue 1: Keep the inventory in the stripping section at a moderate level, ensure that the pressure drop across the single column does not exceed 4 KP, and avoid large fluctuations in the pressure difference between the two columns. For solution to issue 2: Stop the supply of main air first, then resume it; if the pressure drop in the main air distribution pipe exceeds 9 KP, there are many details to take into account – even 2000 words wouldn’t be enough to cover them all

Choose a catalyst of better quality, and control the regeneration temperature properly to prevent thermal degradation of the catalyst; excessive fine powder can lead to losses. Second, it is necessary to regulate the linear velocity of the cyclone separator appropriately. Third, the more stable the operation of the facility, the less loss there will be

In simple terms, it is about maintaining a proper pressure balance between the two devices to prevent large fluctuations in pressure； Supplement in a timely manner to maintain the catalyst particle size distribution, etc.

1. Do a good job in the original design. 2. The key is to carry out proper maintenance and inspection work. 3. Ensure smooth operation to reduce thermal failure.

Reply 1# jbcyf (1) Operating pressure. If the pressure operation is unstable or experiences sudden changes, it will increase the amount of catalyst carried in the flue gas, leading to greater catalyst loss. Therefore, during normal operation, the differential pressure between the two vessels and the pressure in the regenerator should be maintained at equilibrium. (2) Main steam and various types of steam. If the main air volume or steam volume increases or changes significantly, it will raise the linear velocity of the bed and the inlet linear velocity of the cyclone separator, resulting in an increased amount of catalyst being carried away. Especially when a large amount of water vapor carries water or is injected as cooling water in an accident, it not only increases the line speed but also causes severe fragmentation of the catalyst, increasing the amount of fine powder and leading to greater catalyst loss. During operation, while ensuring the optimal conditions for regenerator coking and keeping the carbon content in the regenerant at its lowest level, efforts are made to minimize the main air flow as well as the flow rates of various types of steam and loosening air. Under no circumstances should accident cooling water be sprayed, unless it is absolutely necessary. (3) Burning oil and CO combustion aid. The smoke-to-air ratio for burning oil is 1.13; coupled with the fast burning rate and the gas expansion caused by the high temperatures resulting from combustion. Therefore, after injecting combustion oil, even if the main air flow remains unchanged, it will cause a sudden increase in gas volume, leading to drastic changes in regenerator pressure. The double-acting slide valve opens and closes abruptly, resulting in significant loss of catalyst. On the other hand, since the fuel is injected in a localized manner, it leads to unevenness throughout the bed layer (which is further exacerbated by poor atomization). Therefore, try not to use burning oil. To use it, the amount of combustion oil must be adjusted slowly, while ensuring good atomization of the combustion oil. After using an oxidizer, it is possible to stop spraying the combustion oil. At the same time, it **reduces the occurrence of secondary combustion, thereby decreasing the need to use various cooling steams and cooling waters, which helps to minimize catalyst degradation. (4) Replacement of fresh catalyst. Since fine particles of 40μm or less account for about 18%–20% in fresh catalysts, to prevent these particles from being carried away by the airflow once they enter the regenerator, the amount of fresh catalyst added should be controlled to be small, following the principle of adding it in small amounts over time. At the same time, it is necessary to maintain stable operation of the two devices. If large-scale feeding is enabled, on the one hand it increases the loss of catalyst after it enters the regenerator; on the other hand, if operational adjustments are not made in a timely manner when the amount of coke formed increases, carbon buildup will occur, leading to drastic changes in operations and increased catalyst loss. (5) Properties of crude oil. If the properties of the feed oil change too frequently and drastically, it will cause disruptions in the entire operation, which is highly detrimental to reducing catalyst loss. When the crude oil contains water, the operational impact is particularly significant. (6) Smooth operation. If the process conditions and operations are not proper, it can lead to significant changes in the pressure of the carbon bed or the afterburner, as well as in the pressures of the two reactors. This disrupts the eight balances within the system; in severe cases, it may even be necessary to stop feeding material, and other types of accidents can occur, forcing the plant to shut down. All of these situations can result in a dramatic increase in catalyst loss. Therefore, operations must be carried out smoothly to ensure safe production. (7) Select an appropriate bed linear velocity and catalyst inventory to reduce the concentration at the inlet of the cyclone separator.

As a supplementary note: sometimes the lining comes off and falls into the centrifugal separation leg, which can also cause significant loss of material. If inertial separation is used at the outlet of the lift pipe, an excessive pressure drop in that separation system can likewise lead to substantial material loss. Furthermore, there is an unstable zone above the bed layer, and if the material leg outlet is located in this zone, it will also lead to a poor separation effect.

Operate smoothly, avoid large fluctuations in pressure, and pay attention to adjusting the fuel oil misting vapor

Operate smoothly, avoid pressure fluctuations, and adjust the fuel oil atomization steam properly