Alpha-Olefin Feed Stream Pressurization for Comonomer Absorption
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Solution Overview
Problem
Existing solution polymerization processes face challenges in efficiently recycling volatile reactants and comonomers, leading to significant losses and increased process complexity due to the need for careful control of volatile components and varying pressure levels for different comonomers, which affects economic efficiency and versatility.
Innovation Solution
A process for preparing an alpha-olefin feed stream by pressurizing a low-pressure initial stream to medium and high pressure levels, allowing introduction of alpha-olefin monomers and comonomers at varying pressure levels, optimizing the feed stream composition and reducing the need for separate hydrogen compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If volatile components are removed by venting off, then volatile impurities are eliminated, but volatile reactants are significantly lost
Solution Approach 1:
A liquid absorbent medium is introduced as an intermediary substance between the gaseous recycle stream and the final feed stream. The absorbent selectively absorbs volatile reactants (ethylene, propylene) and comonomers from the gas phase, transferring them into the liquid phase where they can be retained and later reintroduced to the polymerization process, thereby eliminating direct venting losses while still removing harmful volatile impurities.
Solution Approach 2:
Instead of discarding the volatile components through venting, the process recovers volatile reactants and comonomers by absorbing them into a liquid stream. The absorbed components are then stripped from the liquid phase and reintroduced into the polymerization feed, achieving both impurity removal and valuable material recovery.
2Ease of manufacture
If comonomers are dosed at low pressure, then process economics improve, but absorption capacity and dissolution are insufficient
Solution Approach 1:
The process utilizes pressure changes as a key parameter to control comonomer absorption and dissolution. By introducing comonomers at low pressure initially and then increasing pressure in subsequent stages, the system achieves both economic benefits of low-pressure dosing and the required high concentration through pressure-induced enhanced absorption capacity in the liquid phase.
Solution Approach 2:
Comonomers are introduced into the liquid absorbent stream at low pressure in advance, allowing preliminary absorption to occur. Subsequently, pressure is increased to enhance the dissolution capacity and achieve the required comonomer concentration in the final feed stream, separating the dosing action from the concentration achievement.
3Quantity of substance
If multiple comonomers are dosed at various pressure levels, then absorption capacity is optimized, but process complexity increases
Solution Approach 1:
Multiple comonomer dosing operations at different pressure levels are merged into a single integrated liquid-phase absorption process. Different comonomers (1-butene, 1-octene, etc.) are introduced together or sequentially into the same liquid absorbent stream, which handles their absorption and concentration simultaneously, reducing the need for separate dosing systems and control mechanisms.
Solution Approach 2:
The liquid absorbent stream serves multiple functions: it absorbs different types of comonomers (C4, C8, C10), handles pressure transitions, enables concentration control, and facilitates subsequent stripping and reintroduction. This multi-functional approach replaces multiple specialized dosing systems with a single versatile absorption-stripping unit.
4Loss of energy
If recycle streams are used, then material and energy are conserved, but volatile reactant losses increase due to venting requirements
Solution Approach 1:
The liquid absorbent acts as an intermediary carrier that intercepts volatile reactants from the recycle gas stream before they can be vented. The absorbent transfers these valuable components into the liquid phase, where they are protected from loss during the venting operation, thereby preserving both material and the thermal energy associated with the recycle stream.
Solution Approach 2:
The process recovers volatile reactants that would otherwise be discarded with the vent stream. By absorbing and subsequently stripping these components, the system retains valuable materials from the recycle stream while still allowing necessary venting of harmful impurities, thus preventing reactant loss without compromising the energy recycling benefit.
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 enhances the absorption of comonomers and monomers at elevated pressures, reducing reactant losses and process complexity, thereby improving process economics and versatility for producing alpha-olefin polymers with higher comonomer content and varied product properties.
Implementation Method 1
pressurizing the low-pressure initial stream to a medium pressure level in the range of from greater than 15 to 45 barg to form a medium-pressure initial stream; pressurizing the medium-pressure initial stream to a high pressure level in the range of from greater than 45 to 300 barg to form a high-pressure initial stream
Data Source
AI summary
The present invention relates to a process for preparing an alpha-olefin feed stream comprising providing a low-pressure initial stream comprising a hydrocarbon solvent at a low pressure level in the range of from below atmospheric pressure to 15 barg; pressurizing the low-pressure initial stream to a medium pressure level in the range of from greater than 15 to 45 barg to form a medium-pressure initial stream; pressurizing the medium-pressure initial stream to a high pressure level in the range of from greater than 45 to 300 barg to form a high-pressure initial stream; wherein a monomer stream comprising an alpha-olefin monomer is introduced into the medium-pressure initial stream at medium pressure level and/or into the high-pressure initial stream at high pressure level, and one or more comonomer streams comprising at least one alpha-olefin comonomer is/are introduced into the low-pressure initial stream at low pressure level, and/or into the medium-pressure initial stream at medium pressure level, and/or into the high-pressure initial stream at high pressure level; to form an alpha olefin feed stream. Alternatively, the medium pressure level may be left out, wherein a monomer stream comprising an alpha-olefin monomer is introduced into the high-pressure initial stream at high pressure level; and one or more comonomer streams comprising at least one alpha-olefin comonomer is/are introduced into the low-pressure initial stream at low pressure level, and/or into the high-pressure initial stream at high pressure level; to form said alpha olefin feed stream. The above processes enable solution polymerisation with reduced process complexity and increased process economics.