Hydrocarbon Recovery in Solution Polymerization Recycle Streams
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Solution Overview
Problem
Existing solution polymerization processes face inefficiencies in recovering residual hydrocarbons, leading to high energy consumption and lack of effective recycling of unreacted monomer and comonomer.
Innovation Solution
A solution polymerization process involving multiple separation stages and recycle streams, with at least 80% of the vapour stream being recycled back to the polymerization reactors, optimizing the recovery of volatile components and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional separation processes are used to recover volatile components from polymer solution, then the unreacted monomer and comonomer can be separated, but the energy consumption is high and recycling efficiency is low
Solution Approach 1:
The patent employs vapor-liquid equilibrium separation where the polymer solution is heated to generate vapor containing unreacted monomer and comonomer, which is then condensed and recycled. This phase transition-based separation method reduces energy consumption compared to conventional distillation while maintaining high recycling efficiency
Solution Approach 2:
The process optimizes temperature and pressure parameters in the separator and fractionator to enhance the recovery of volatile components. By controlling these parameters, the system achieves efficient separation with reduced energy input while maximizing the recycling of monomer and comonomer
2Manufacturing precision
If multiple concentration stages are implemented to remove residual hydrocarbons, then the purification efficiency improves, but the process complexity increases
Solution Approach 1:
The separation process is divided into distinct stages: a separator for initial vapor-liquid separation and a fractionator for further purification. This segmentation allows each unit to be optimized for its specific function, achieving high purification efficiency while keeping individual equipment design relatively simple
Solution Approach 2:
The separator performs preliminary separation of volatile components before the fractionator handles final purification. This preliminary action reduces the load on the fractionator and simplifies the overall process design by distributing complexity across multiple simpler stages
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 process efficiently recovers unreacted monomer and comonomer, significantly reducing energy consumption and enhancing the recycling efficiency of solvent, thereby improving the overall process economy.
Implementation Method 1
passing the first stream of the first solution into a first separator (4) wherein a first liquid phase comprising the polymer and a first vapour phase coexist
Implementation Method 2
passing at least a part of the first vapour stream to a first fractionator (5); withdrawing a first overhead stream and a first bottom stream from the first fractionator (5)
Data Source
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AI summary
The present invention relates to a process for producing a polymer composition comprising the steps of: (A) polymerising, in a first polymerisation reactor in a first solvent, - a first olefin monomer having two or more carbon atoms, - in the presence of a first polymerisation catalyst for producing a first solution comprising a first polymer of the first olefin monomer and the first solvent; (B) withdrawing a first stream of the first solution from the first polymerisation reactor; (C) passing the first stream of the first solution into a first separator wherein a first liquid phase comprising the polymer and a first vapour phase coexist; (D) withdrawing a first vapour stream and a first concentrated solution stream comprising the polymer from the first separator; (E) passing at least a part of the first vapour stream to a first fractionator; (F) withdrawing a first overhead stream and a first bottom stream from the first fractionator; (G) recovering at least a part of the first overhead stream as a first recycle stream and passing it to the first polymerisation reactor; (H) passing the first concentrated solution stream from the first separator (4) to a second separator (8) wherein a second liquid phase comprising the polymer and a second vapour phase coexist; (I) withdrawing a second vapour stream and a second concentrated solution stream comprising the polymer from the second separator; (J) passing at least a part of the second vapour stream to a second fractionator; (K) withdrawing a second overhead stream and a second bottom stream from the second fractionator; (L) recovering at least a part of the second overhead stream as a second recycle stream and passing it to the first polymerisation reactor; (M) passing the second concentrated solution stream from the second separator to a third separator wherein a third liquid phase comprising the polymer and a third vapour phase coexist; characterised in that the mass flow rate of the first recycle stream is at least 80 % of the mass flow rate of the first vapour stream and the mass flow rate of the second recycle stream is at least 70 % of the mass flow rate of the second vapour stream.