Jet Compressor Regeneration of Purification Beds
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Solution Overview
Problem
Current methods for regenerating purification beds in olefin polymerization processes either incur high costs due to once-through nitrogen use or face investment challenges with closed-loop systems, where cooling leads to water condensation and coking risks, and incomplete cycle closure due to evolved impurities.
Innovation Solution
An open-loop recycle method using an inert gas component supplied at a pressure higher than the regeneration composition, with a jet or thermal compressor to compress a mixture of inert gas and recycled gases, allowing partial recycling and venting to reduce costs and avoid cooling-related issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If once-through nitrogen is used for regeneration, then the purification bed can be regenerated effectively, but nitrogen consumption and flaring costs increase significantly
Solution Approach 1:
The patent recovers and recirculates the nitrogen and hydrocarbon mixture from the regeneration outlet back to the regeneration inlet, creating a closed-loop system that continuously reuses the same gas stream. This eliminates the need for continuous nitrogen consumption and flaring, as the gas is repeatedly cycled through the purification bed for regeneration.
Solution Approach 2:
The patent implements continuous recirculation of the regeneration gas stream, maintaining uninterrupted flow through the purification bed. The gas is continuously cooled, compressed, and recirculated, ensuring constant regeneration action without periodic interruptions or complete gas replacement.
2Loss of substance
If closed nitrogen recirculation cycle is used, then nitrogen consumption is reduced, but investment cost increases due to cooling and compression requirements
Solution Approach 1:
The patent uses the hot regeneration gas itself as the cooling medium for the compression system. The hot gas from the regeneration outlet is directed to a heat exchanger that cools the incoming cold gas stream, utilizing the waste heat from the regeneration process to provide cooling without requiring external cooling systems.
Solution Approach 2:
The patent combines the cooling function with the compression function by using a heat exchanger that integrates both temperature control and gas flow management. The system merges the hot and cold gas streams in a controlled manner, allowing heat transfer while maintaining separate flow paths for compression.
3Ease of operation
If cooling is applied to recirculating gas, then compression can be achieved, but water condensation occurs requiring additional separation equipment
Solution Approach 1:
The patent carefully controls the temperature parameter of the recirculating gas to remain above the dew point, preventing water condensation. By maintaining the gas temperature within a specific range through controlled cooling and heating cycles, the system achieves compression without forming condensable liquids that would require separation equipment.
4Reliability
If high temperature heating elements are used for regeneration, then purification bed regeneration is effective, but hydrocarbons may coke out on the heating elements
Solution Approach 1:
The patent introduces a heat exchanger as an intermediary between the high temperature heating elements and the hydrocarbon-containing gas stream. The heat exchanger transfers thermal energy from the hot regeneration gas to the incoming cold gas, providing controlled heating that avoids direct contact between high temperatures and hydrocarbons, thus preventing coking while maintaining regeneration effectiveness.
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 reduces nitrogen use and flaring, lowers operating and investment costs, and minimizes coking risks by eliminating the need for continuous pre-cooling and allowing for efficient regeneration with reduced pressure drops and hydrocarbon exposure.
Implementation Method 1
One or more jet or thermal compressors may be employed to compress a mixture of inert gas at pressure P1 and a recycled portion of the inert gas and evolved regeneration gases at pressure P3
Implementation Method 2
the inert gas component is supplied at a pressure P1, where P1 is greater than a pressure P2 of a regeneration composition being routed to the purification bed being regenerated
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Methods and systems for regenerating a purification bed take advantage of inert gas pressure, such as, for example, supplied by a pipeline. The inert gas (102) is provided at a first pressure and combined with a recycle composition (116) from the vessel (110, 110a) containing the material being regenerated. These streams form a regeneration fluid composition (114) at a second pressure less than the inert gas pressure, which is then routed to the vessel to regenerate the purification bed. A jet compressor (108) may be used for the combining of the inert gas and recycle streams. The recycled composition allows reduction in inert gas usage, while a portion is flared or otherwise disposed of.