In-situ Hydrogen Removal for High MW EPR Control
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Solution Overview
Problem
Current production systems for olefin copolymers face limitations in achieving high molecular weight ethylene-propylene rubber (EPR) due to carryover of chain terminating agents like hydrogen, leading to difficulties in controlling molecular weight and transitioning to high MW EPR conditions, resulting in non-spec product and prolonged processing times.
Innovation Solution
A process involving a first reactor system producing a semi-crystalline polymer and a chain terminating agent, with the product stream transferred to a second reactor system where a low crystallinity polymer is formed in the presence of the semi-crystalline polymer, and the chain terminating agent is removed via an in-situ process, such as a slipstream circuit with a hydrogen removal unit, to facilitate quicker transitions to high MW EPR conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chain terminating agent (hydrogen) is removed using low pressure separation equipment between reactors, then high MW EPR can be produced, but equipment complexity and energy consumption increase
Solution Approach 1:
The patent extracts the chain terminating agent (hydrogen) removal function from a separate low pressure separation equipment and integrates it into the monomer circuit of the second reactor system. This is achieved by placing a hydrogen removal unit (membrane separator or catalytic reactor) directly within the monomer recirculation loop, allowing in-situ removal of hydrogen without requiring external separation equipment.
Solution Approach 2:
The patent combines the hydrogen removal function with the existing monomer circuit system. The hydrogen removal unit is integrated into the monomer recirculation loop, merging two previously separate functions (monomer recirculation and chain terminating agent removal) into a single unified system, thereby reducing overall equipment complexity.
2Manufacturing precision
If low pressure separation equipment is added to remove chain terminating agent, then EPR molecular weight increases, but energy consumption increases due to re-pressurization requirements
Solution Approach 1:
The patent extracts the hydrogen removal function from a separate low pressure separation process and integrates it directly into the monomer circuit of the second reactor system. By placing the hydrogen removal unit within the existing pressurized monomer recirculation loop, the system avoids the energy-intensive re-pressurization step that would be required if hydrogen removal occurred at low pressure in a separate equipment.
Solution Approach 2:
The monomer circuit in the second reactor system serves multiple functions: it recirculates monomer for polymerization, maintains system pressure, and now also removes chain terminating agent through the integrated hydrogen removal unit. This multi-functionality eliminates the need for separate energy-intensive pressurization equipment.
3Productivity
If transitions to high MW EPR conditions are made without in-situ hydrogen removal, then non-spec product is generated for extended periods, but adding separation equipment increases complexity
Solution Approach 1:
The patent extracts the hydrogen removal capability from external separation equipment and integrates it directly into the monomer circuit of the second reactor system. This allows rapid in-situ removal of chain terminating agent when transitioning to high MW EPR conditions, enabling quick product specification changes without the lag associated with external separation equipment.
Solution Approach 2:
The integrated hydrogen removal unit in the monomer circuit provides immediate feedback control over chain terminating agent concentration. When transitioning to high MW EPR conditions, the system can rapidly adjust hydrogen removal rates through the membrane separator or catalytic reactor, enabling quick stabilization at target molecular weights and reducing non-spec product generation.
4Manufacturing precision
If chain terminating agent concentration is controlled using traditional methods, then molecular weight control is difficult, but in-situ removal requires additional equipment
Solution Approach 1:
The patent extracts the chain terminating agent removal function from traditional external separation equipment and integrates it directly into the monomer circuit. The hydrogen removal unit (membrane separator or catalytic reactor) is placed within the existing pressurized monomer recirculation loop, enabling precise in-situ control of hydrogen concentration without requiring external separation equipment.
Solution Approach 2:
The patent changes the operational parameters of the monomer circuit by integrating a hydrogen removal unit that can dynamically adjust chain terminating agent concentration. The membrane separator or catalytic reactor allows continuous modulation of hydrogen levels, providing precise control over EPR molecular weight through parameter adjustment rather than discrete separation steps.
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 enables more rapid and controlled production of high MW EPR, reducing non-spec product generation and improving molecular weight control, thereby enhancing the quality and efficiency of the copolymer production process.
Implementation Method 1
a monomer circuit to recirculate monomer through a reactor in the second reactor system
Implementation Method 2
removing chain terminating agent, e.g., molecular hydrogen, from a slipstream circuit in recirculating communication with the monomer circuit
Data Source
AI summary
In a process for making a copolymer, a first product stream comprising a semi-crystalline polymer and a chain terminating agent is produced in a first reactor system. The first product is provided to a second reactor system wherein a low crystallinity polymer is produced in the presence of the semi-crystalline polymer. At least a portion of the chain terminating agent is removed from the second reactor system by an in-situ process.