Adsorbent Bed Regeneration Without Recycle Compressors
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Solution Overview
Problem
Conventional natural gas dehydration systems require large compressors to recycle hot dry gas, which are costly and can lead to operational inefficiencies if they become inoperable.
Innovation Solution
A process and system that bypasses or eliminates the need for compressors by using a multi-bed adsorbent system with pressure differentials and regeneration gas recycling, allowing for efficient dehydration and contaminant removal without compressors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional dehydration system uses a compressor to recycle hot dry gas, then the system can maintain proper pressure and flow for regeneration, but the capital cost and operating expenses increase significantly
Solution Approach 1:
The patent removes the compressor from the system entirely by reconfiguring the flow paths. The regeneration gas is routed directly from the dehydration unit outlet back to the inlet without requiring compression, extracting the problematic component while maintaining system functionality through alternative flow management
Solution Approach 2:
The system uses its own product gas as the regeneration gas source, creating a self-sufficient cycle. The hot dry gas produced during dehydration automatically serves as the regeneration medium, eliminating the need for external compression equipment and reducing overall system complexity
2Productivity
If a large compressor is installed to return hot dry natural gas upstream, then regeneration can be maintained, but capital expenses and operating costs increase
Solution Approach 1:
The system dynamically switches between different operational modes for each bed (dehydration mode and regeneration mode) and uses variable flow distribution. The slip stream ratio and flow paths are adjusted based on system needs, allowing efficient operation without the constant high-pressure capability provided by large compressors
Solution Approach 2:
The patent changes the pressure and temperature parameters of the regeneration gas by routing it through different paths and utilizing heat exchange with the adsorbent beds. The gas undergoes controlled cooling and pressure adjustment as it moves through the system, achieving the required conditions for regeneration without mechanical compression
3Reliability
If hot dry gas is passed over saturated adsorbent for regeneration, then water and contaminants are desorbed, but a large compressor is required to return the gas upstream
Solution Approach 1:
The patent introduces heat exchange units and flow control devices as intermediaries between the dehydration outlet and the regeneration inlet. These intermediaries manage the gas cooling and pressure adjustment, allowing the regeneration process to occur at lower pressures without requiring large compressors for gas recycling
Solution Approach 2:
The system maintains continuous operation by having multiple beds in different phases (dehydration and regeneration) simultaneously. The regeneration gas flow is continuously supplied from the dehydration outlet, creating an uninterrupted cycle that eliminates the need for batch compression and reduces operational complexity
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
Reduces capital and operating expenses while improving system reliability by eliminating the need for compressors and maintaining operation even if they fail.
Implementation Method 1
natural gas is often dehydrated or cleared from contaminants by passing the natural gas through a system of vessels or units referred to as a dehydration unit or a contaminant removal unit including adsorption beds made up of adsorbent material (e.g., molecular sieve particulate material). During dehydration mode and/or adsorption mode, water and/or contaminants are adsorbed onto the adsorbent (e.g., molecular sieve material)
Implementation Method 2
The slip stream is passed into the second vessel that is in regeneration mode such that the slip stream is used as a regeneration gas for the second vessel. All portions of a first bed in the first adsorbent bed containing vessel and all portions of a third bed in the third adsorbent bed containing vessel, in adsorption mode, have a temperature that is at least 75° C. lower than the temperature of a second bed in the second adsorbent bed containing vessel that is in regeneration mode
Implementation Method 3
During regeneration mode, water and/or contaminants are desorbed from the adsorbent (e.g., molecular sieve). Typically, the regeneration is effected by passing hot dry natural gas, i.e., natural gas having been dehydrated or decontaminated from heavy hydrocarbons (e.g., C5+ hydrocarbons), over the saturated adsorbent (e.g., molecular sieve)
Data Source
AI summary
Disclosed herein is a system including at least two adsorbent bed containing vessels in adsorption mode, where one has a high pressure PI and one has a low pressure P3, and at least one adsorbent bed containing vessel in regeneration mode. The vessel that is in regeneration mode may have a pressure P2 that is intermediate to the pressures PI and P3 of each of the vessels that are in adsorption mode. The system may be configured to introduce a gas feed stream into the high pressure (P3) vessel to generate a first product stream, followed by passing a slip stream from the first product stream, to act as a regeneration gas, into the vessel that in regeneration mode, followed by passing the regeneration gas into the low pressure (P3) vessel, without passing through a compressor, to generate a second product stream.