How is the pre-lift steam volume in a catalytic cracking riser controlled, and what are the criteria for making such decisions?
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How is the pre-lift steam volume in a catalytic cracking riser controlled, and what are the criteria for making such decisions?
Generally, the pre-heating steam is equipped with control valves as well as orifice flow meters, so it should be easy to control
Pre-lift steam ensures the lifting effect in the pre-lift section and prevents blockages; this can be determined through the pressure drop in that section
Pre-rising section pressure drop, density, riser pressure drop
The key is to control the density of the catalyst in the pre-raising section; it is generally kept around 400, which indicates good fluidization of the catalyst
Control the density of the pre-lift section, use a rectifying catalyst to prevent catalyst backmixing
Controlling the density and pressure drop in the pre-lift section means controlling an appropriate pre-lift linear velocity