Gas Phase Polymerization Gas Recycling with Dual Compressors
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Solution Overview
Problem
In gas phase polymerization processes, pressure and energy losses occur due to the need for branching off flush gases and subsequent pressure adjustments in the circulation loop, leading to inefficiencies in energy consumption and material handling.
Innovation Solution
A process involving a circulation gas compression unit and a flush gas compression unit, where the unreacted gas stream is pressurized, branched into a circulation gas stream and a flush gas stream, allowing for precise pressure adjustment in the circulation loop and eliminating the need for choking valves, thereby reducing energy losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the circulation gas flow is artificially choked with a flow restriction element to generate sufficient pressure margin for the flush gases, then the pressure level for flush gases is sufficient, but the power consumption of the compressor increases
Solution Approach 1:
The patent divides the gas compression into two separate stages: a circulation gas compressor for the main circulation loop and a dedicated flush gas compressor for the flush gas stream. This segmentation allows each compressor to be optimized for its specific function, eliminating the need to choke the main circulation flow to generate pressure margins.
Solution Approach 2:
The patent extracts the flush gas compression function from the main circulation gas compressor by introducing a separate flush gas compressor. This extraction allows the main compressor to operate efficiently without the additional burden of providing pressure margins for flush gases through artificial choking.
2Stability of the object's composition
If parts of the circulation gas are led to a recovery area for composition adjustment, then the gas composition is properly adjusted, but the pressure drops significantly requiring additional pressurization
Solution Approach 1:
The patent segments the gas handling into separate streams: the main circulation gas stream that maintains pressure for reactor feed, and the flush gas stream that can be diverted to recovery areas for composition adjustment. This segmentation allows composition adjustment without compromising the pressure stability of the main circulation loop.
Solution Approach 2:
The patent introduces an intermediary flush gas compressor that handles the pressure adjustment for gases diverted to recovery areas. This intermediary compressor allows composition adjustment in the recovery area while maintaining the pressure integrity of the main circulation loop.
3Stress or pressure
If the circulation gas stream is pressurized to high pressure levels, then the pressure margin for flush gases is sufficient, but the energy consumption increases significantly
Solution Approach 1:
The patent segments the compression function so that the circulation gas compressor only provides the pressure needed for the main circulation loop, while a separate flush gas compressor provides the additional pressure margin for flush gases. This eliminates the energy waste of pressurizing the entire circulation gas stream to high levels.
Solution Approach 2:
The patent applies different pressure levels to different parts of the system: the main circulation loop operates at an optimized pressure level for fluidization, while the flush gas stream is pressurized to a higher level only where needed. This local differentiation of pressure quality minimizes overall energy consumption.
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 energy efficiency by minimizing pressure and material losses, reducing the shaft power required for compression, and simplifying the system by eliminating the need for additional pressure adjustment steps, resulting in a more efficient gas phase polymerization process.
Implementation Method 1
pressurizing the unreacted gas stream (4) in a circulation gas compression unit (5) yielding a pressurized unreacted gas stream (7)
Implementation Method 2
pressurizing the pressurized unreacted gas (7) stream in a flush gas compression unit (6) yielding a flush gas stream (9)
Implementation Method 3
fluidized bed gas phase reactors, in which the polymerization reaction and therefore the quality of the product benefits from the adjusted monomer gas stream in the reactor
Data Source
AI summary
A gas phase polymerization assembly comprising a gas phase polymerization reactor having at least one inlet and at least one outlet, a circulation gas compression unit having an inlet and an outlet, whereby the inlet of the circulation gas compression unit is fluidly connected to the at least one outlet of the gas phase polymerization reactor by an unreacted gas line; a flush gas compression unit having an inlet and an outlet, wherein the inlet of the flush gas compression unit is fluidly connected to the outlet of the circulation gas compression unit by a pressurized unreacted gas line; a circulation line fluidly connecting the pressurized unreacted gas line with the at least one inlet of the gas phase polymerization reactor; a flush gas withdrawal line connected to the outlet of the flush gas compression unit.