Fluidized Bed Reactor Outlet Filter Temperature Control
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Solution Overview
Problem
The production of chloropolysilane in fluidized-bed reactors faces challenges with reduced yield due to unreacted silicon particles escaping and causing blockages, and higher-order silicon chloride by-products attaching to filters, leading to reactor blockages and impurity mixing in the reaction product.
Innovation Solution
A method involving a vibration-type reactor with an outlet filter positioned upstream of the product outlet, set at 210-350°C, and a second filter to prevent fine particles from escaping, made from materials like sintered metal, ceramic, or polytetrafluoroethylene, to enhance yield and prevent blockages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an outlet filter is provided to prevent fine particles from flowing out, then manufacturing precision is improved, but the filter becomes blocked by higher-order silicon chloride
Solution Approach 1:
The patent applies parameter changes by controlling the temperature of the outlet filter within the specific range of 210-350°C. This temperature parameter is optimized to prevent condensation of higher-order silicon chloride on the filter surface, thereby maintaining filter permeability while still capturing fine particles. The temperature parameter directly addresses the contradiction by changing the physical state conditions to prevent harmful condensation.
Solution Approach 2:
The outlet filter serves as an intermediary component between the reaction zone and the product collection system. It mediates the separation of fine particles from the product stream while the temperature control system acts as another intermediary to prevent chloride condensation on the filter surface, resolving the blockage issue.
2Productivity
If the reaction temperature is increased to improve reaction rate, then productivity is improved, but unreacted silicon particles are blown out causing yield loss
Solution Approach 1:
The patent segments the particle separation function from the temperature control function by introducing a dedicated outlet filter with specific temperature control. This allows the reaction zone to operate at high temperatures for improved productivity while the filter zone maintains conditions optimized for particle capture, resolving the contradiction between reaction rate and particle retention.
Solution Approach 2:
The outlet filter acts as a disposable or easily replaceable component that can be removed and cleaned or replaced when blocked by higher-order silicon chloride. This allows the main reaction system to continue operating at high temperatures for productivity while the filter handles the particle separation task independently.
3Loss of substance
If a dust collector is provided to collect silicon particles, then loss of substance is reduced, but higher-order chloride causes blockage in the reactor
Solution Approach 1:
The patent applies parameter changes by controlling the outlet filter temperature at 210-350°C, which is specifically designed to prevent condensation of higher-order silicon chloride. This temperature parameter transformation converts the potential blockage problem into a solvable condition where chloride remains in vapor phase and does not accumulate on the filter surface.
Solution Approach 2:
The patent converts the harmful effect of higher-order silicon chloride (which would normally condense and block the filter) into a beneficial situation by maintaining the filter temperature above the condensation point. The chloride that would otherwise be harmful now serves to indicate proper temperature control while the filter continues to capture fine particles effectively.
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
The solution effectively prevents silicon particles and higher-order silicon chloride from escaping, improving reaction yield, reducing blockages, and minimizing impurity mixing, while allowing for filter reuse through alkali treatment, thus enhancing the environmental sustainability of the process.
Implementation Method 1
an outlet filter preventing fine particles blown up by fluidization from flowing out of the reaction tank through the product outlet
Implementation Method 2
a temperature of the outlet filter being set in a range of 210 to 350°C, thereby preventing attachment of higher-order silicon chloride as a by-product to the outlet filter
Implementation Method 3
a vibration-type reactor with an outlet filter positioned upstream of the product outlet
Data Source
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AI summary
Disclosed is a method for producing chloropolysilane by which the yield of a fluid reaction to produce the chloropolysilane is improved while blockage in a reactor caused by attachment of higher-order silicon chloride as a by-product is prevented. In producing the chloropolysilane by reacting fluidized silicon particles or silicon alloy particles with a chlorine gas, an outlet filter 22 is provided, upstream from a product outlet 20 that releases a reaction product, above the area in which the silicon particles or silicon alloy particles are fluidized inside a reaction tank 12. The outlet filter 22 prevents fine particles blown up by fluidization from flowing out of the reaction tank 12 through the product outlet 20. A temperature of the outlet filter 22 is set in a range of 210 to 350°C.