Gas Solids Olefin Polymerization Reactor Cooling Capacity
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Solution Overview
Problem
Gas solids olefin polymerization reactors face challenges in cooling efficiency due to limited mixing of fluidization gas with polyolefin powder, leading to reduced heat exchange and cooling capacity.
Innovation Solution
A method involving the introduction of a cooled fluidization gas stream into the middle zone of the reactor through specific feeding ports, enhancing mixing and heat exchange by reintroducing the cooled gas as a third stream into the dense phase, thereby improving cooling capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the superficial gas velocity of the fluidization gas stream is limited to prevent excessive polyolefin powder entrainment, then polyolefin powder entrainment is reduced, but mixing efficiency and heat exchange are reduced
Solution Approach 1:
The invention divides the fluidization gas stream into two separate streams: a first stream introduced at the bottom zone for basic fluidization, and a second cooled stream introduced at the middle zone for enhanced cooling. This segmentation allows each stream to perform its specific function optimally without compromising the other, resolving the contradiction between preventing powder entrainment and maintaining heat exchange efficiency
Solution Approach 2:
The invention introduces a cooled second stream of fluidization gas as an intermediary cooling medium in the middle zone. This cooled stream acts as a mediator that enhances heat exchange between the polymer particles and the gas phase without requiring high gas velocities that would cause powder entrainment, thus resolving the contradiction
2Productivity
If the superficial gas velocity is increased to improve mixing and heat exchange, then cooling capacity is improved, but polyolefin powder entrainment increases
Solution Approach 1:
The invention segments the cooling function from the fluidization function by introducing cooled gas at the middle zone separately from the bottom zone fluidization gas. This allows high cooling capacity to be achieved through the second stream without increasing the superficial gas velocity in the first stream that would cause powder entrainment
Solution Approach 2:
The invention applies different gas stream characteristics to different zones: the first stream at the bottom zone provides stable fluidization with controlled velocity to prevent entrainment, while the second cooled stream at the middle zone provides intensive cooling. Each zone receives the appropriate quality of gas stream for its specific function
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 method results in more even temperature profiles and homogeneous polymerization conditions, reducing the risk of off-spec polymer production and enhancing heat removal efficiency.
Implementation Method 1
enhancing the mixing of the fluidized gas with the polyolefin powder in the dense phase resulting in improved heat exchange and cooling capacity
Data Source
AI summary
The present invention relates to a method for improving the cooling capacity of a gas solids olefin polymerization reactor by splitting the fluidization gas and returning part of the fluidization gas to the reactor into the bottom zone of the reactor and another part of the fluidization gas directly into the dense phase formed by particles of a polymer of the at least one olefin suspended in an upwards flowing stream of the fluidization gas in the middle zone of the reactor.