Polyethylene-Silane Copolymer Feed Segmentation
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Solution Overview
Problem
The production of polyethylene-silane copolymers faces issues such as volatile silane comonomers escaping through equipment wear, leading to maintenance downtime, premature polymerization causing plugging, and adverse effects on compressor lubrication due to high silane concentrations.
Innovation Solution
Separately feeding ethylene and silane comonomers into the process, with silane being added after the compressor unit and potentially along the reactor, avoiding pre-mixing during compression and allowing for controlled conversion within the reactor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If silane comonomer is mixed with ethylene feed before compression, then conversion of silane comonomer is improved, but silane deposits form in compressor leading to maintenance downtime
Solution Approach 1:
The patent divides the feed streams into separate paths: ethylene is compressed first, then silane comonomer is added after compression. This segmentation prevents silane from being present during the compression process, eliminating deposit formation while maintaining conversion efficiency through subsequent mixing before polymerization.
Solution Approach 2:
The patent performs preliminary compression of ethylene without silane, avoiding the harmful interaction between silane and compressor components. The silane is then introduced in a preliminary mixing step before polymerization, ensuring high conversion without exposing the compressor to silane-related problems.
2Strength
If silane comonomer is added to ethylene feed, then crosslinking capability of polymer is improved, but premature polymerization occurs causing plugging
Solution Approach 1:
The patent prepares the ethylene feed and silane comonomer separately before combining them. By delaying the mixing until after compression and using controlled addition rates, the system prevents premature polymerization while ensuring sufficient silane is present for crosslinking during the intended polymerization process.
Solution Approach 2:
The patent controls the timing and concentration of silane addition by changing process parameters: silane is added after compression at controlled rates, and polymerization conditions (temperature, pressure, catalysts) are optimized to initiate polymerization only under controlled conditions, preventing premature reactions.
3Quantity of substance
If high concentration of silane is present in feed, then copolymer composition is improved, but lubrication of compressor is adversely affected
Solution Approach 1:
The patent separates the compression process from the silane-containing feed stream. Ethylene is compressed alone or with minimal contaminants, then silane is added after compression. This ensures high silane content in the final copolymer while protecting the compressor lubrication system from silane-related degradation.
Solution Approach 2:
The patent extracts silane from the pre-compression feed stream and introduces it separately after compression. This removal of silane from the compression process eliminates its harmful effects on lubrication while maintaining its presence in the polymerization feed for achieving desired copolymer composition.
4Stability of the object's composition
If silane comonomer is compressed with ethylene, then mixing efficiency is improved, but wear of sealing increases leading to silane leakage
Solution Approach 1:
The patent segments the process into compression of ethylene followed by separate addition of silane. This eliminates silane's presence during compression, preventing sealing wear and leakage. Subsequent mixing before polymerization ensures adequate mixing efficiency for copolymer formation without exposing seals to silane.
Solution Approach 2:
The patent extracts silane from the compression feed and introduces it separately after compression. This removes the source of sealing wear and leakage from the compression process while maintaining mixing efficiency through controlled addition and subsequent polymerization conditions.
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 approach reduces the formation of silane deposits, decreases maintenance needs, and enhances overall process efficiency by minimizing unreacted silane passage and lubrication issues, thereby reducing downtime and operational costs.
Implementation Method 1
crosslinking is carried out by moisture curing wherein in a first step the silane groups are hydrolysed resulting in the formation of silanol groups
Implementation Method 2
in a second step are crosslinked by a condensation reaction releasing water
Implementation Method 3
The crosslinking is initiated by heating in a subsequent vulcanisation step in a manner that peroxide is decomposed under formation of free radicals
Implementation Method 4
peroxide is decomposed under formation of free radicals
Implementation Method 5
a compressor unit for compressing the ethylene feed
Implementation Method 6
a preheater for pre-heating the ethylene feed
Data Source
Figure 1~2A
Figure 2B
Figure 3~4
AI summary
The present invention relates to a process for manufacturing polyethylene-silane copolymer conducted in a plant comprising at least one compressor unit (10) and at least one reactor (30) being downstream of the compressor unit (10) the process comprising the steps of a) Feeding a first feed stream (1) comprising ethylene into the at least one compressor unit (10) and subsequently to the at least one reactor (30), and b1) Feeding a second feed stream (2) comprising at least one silane comonomer to the at least one reactor (30) as front feed and/or b2) Feeding a second feed stream (2) comprising at least one silane comonomer to the at least one reactor (30) at at least one location along the reactor (30).