Spouted Bed Gas Discharge Nozzle for Polyolefin Production
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Solution Overview
Problem
Spouted bed devices face inefficiencies in solid-gas contact in the annular particle bed portion, leading to particle discharge issues and increased pressure loss, which complicates the production of polyolefins like polyethylene and polypropylene.
Innovation Solution
A spouted bed device with a vertically extending cylinder, a closing plate, a decreasing diameter member with a gas inlet orifice, and laterally discharging gas nozzles above the spouted bed, enhancing gas diffusion into the annular particle bed while minimizing particle discharge and pressure loss, and optionally incorporating deflectors to prevent particle scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a gas outlet is provided in the sidewall of the cylindrical vessel where the annular particle bed is formed, then the solid-gas contacting efficiency is improved, but many particles are discharged from the discharge outlet requiring substantial filtration or recovery units
Solution Approach 1:
The gas outlet is repositioned from the sidewall (horizontal dimension) to the top surface (vertical dimension) of the cylindrical vessel. This dimensional change allows gas to be discharged from a location above the spouted bed rather than from the region where the annular particle bed is formed, thereby improving solid-gas contact efficiency while preventing particle discharge that would require substantial filtration units
2Device complexity
If gas is discharged directly from the top of the reaction zone, then the device construction is simple, but the solid-gas contacting efficiency in the annular particle bed portion is insufficient
Solution Approach 1:
The gas discharge function is segmented into multiple lateral discharge outlets positioned at different locations on the top surface of the cylindrical vessel. This segmentation allows gas to be discharged from multiple points above the spouted bed, enhancing diffusion into the annular particle bed and improving solid-gas contacting efficiency while maintaining relatively simple device construction
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration significantly improves solid-gas contacting efficiency, reduces the need for large filtration or recovery units, and achieves higher volume efficiency and narrower residence time distribution of particles, facilitating the production of high-quality polyolefins.
Implementation Method 1
under the action of a gas introduced at a high velocity from a gas inlet orifice provided at the bottom end of a cylindrical vessel, there forms a spout (sometimes referred to below as the 'spout portion') which has a dilute particle concentration near the center axis of the particle bed held within the vessel and in which particles flow upward together with the gas
Implementation Method 2
the gas that has flowed inward and upward from the gas inlet orifice, instead of being discharged directly from the top of the reaction zone, is discharged laterally from a gas discharge nozzle formed in the cylinder, thereby increasing the amount of gas which diffuses through the annular particle bed portion of the spouted bed
Implementation Method 3
at the periphery of the spout an annular particle bed where particles fall in a moving bed state under the influence of gravity
Data Source
AI summary
A spouted bed device of the present invention includes a cylinder which extends vertically; a closing plate which closes a top end of the cylinder; a decreasing diameter member which is formed at a bottom end of the cylinder, has an inside diameter that decreases progressively downward, and has a gas inlet orifice at a bottom end thereof; and a gas discharge nozzle which passes through the cylinder from an inside surface to an outside surface thereof and which discharges gas from a treatment zone enclosed by a top surface of the decreasing diameter member, a bottom surface of the closing plate and the inside surface of the cylinder. The gas discharge nozzle is provided above a spouted bed which is formed within treatment zone.