Dry gas and steam pre-lift issue
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Currently, the pre-lift medium at the bottom of catalytic cracking riser reactors consists of both steam and dry gas. Should it be made up entirely of dry gas, or should both dry gas and steam be used together? What is the optimal proportion? I kindly ask the experts in catalysis for their guidance
Whether to use dry gas or steam depends on the equipment, and a comprehensive consideration of the actual operating conditions of the equipment is required. If the pressure compressor and absorption stabilization system are designed to handle large volumes of flow, more dry gas can be used as the lifting medium. During the summer, when temperatures are high and the volume of processing is large, the amount of dry gas used can be reduced. Using a large amount of steam will increase the energy consumption of the device; generally, the ratio of dry gas to steam is around 1.5:1.
We use less steam here, maintaining a slight excess, with the rest being dry gas.
Is there a lot of steam? Let’s increase the amount of dry gas slightly less. High levels of dry gas or large fluctuations in its amount can affect the compressor
It’s probably better to use a drier setting. During normal production, we only use dry gas, as steam can cause thermal degradation of the catalyst, leading to an increase in its consumption per unit of product. It will also increase the cooling load of the fractionator overhead gas system.
Use only dry gas; switch to steam in case of an accident. Using dry gas can not only reduce catalyst thermal degradation but also decrease the dry gas production
Try not to use them together in the same sleeve or showerhead； When the dry gas temperature is low and the superheat of the steam is not well controlled, their mixing can lead to the condensation of steam; in such cases, it is considered that water comes into contact with the catalyst in a liquid state. Apart from preventing freezing and condensation, steam must not enter; in case of an accident, it should be switched back to steam. As long as the barometer has sufficient capacity, using dry gas as a pre-lifting medium to create a reducing environment within the lift pipe, suppress heavy metals, and reduce the load associated with cooling during distillation is quite effective.