Rapid-Cycle Swing Adsorption for Low-Temperature Gas Dehydration
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Solution Overview
Problem
Conventional natural gas dehydration processes using temperature swing adsorption (TSA) molecular sieve systems are costly, require large and heavy equipment, and involve high-temperature purge gases that lead to hydrothermal degradation and coke formation, posing safety concerns and increasing capital and operating expenses.
Innovation Solution
A swing adsorption process utilizing rapidly cycled adsorbent beds with a purge stream at temperatures below 450°F (232.2°C), generated by compression, to reduce hydrothermal degradation and coke formation, and eliminating the need for fired furnaces, thereby reducing equipment size, weight, and capital investment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-temperature purge gas (≥500°F) is used in conventional TSA molecular sieve process, then dehydration efficiency is improved, but hydrothermal degradation and coke formation occur leading to adsorbent deactivation
Solution Approach 1:
The patent changes the temperature parameter of the purge gas from conventional high temperature (≥500°F) to moderate temperature (200-450°F). This parameter change maintains adequate dehydration efficiency while preventing hydrothermal degradation and coke formation that occur at higher temperatures, thus resolving the contradiction between dehydration efficiency and adsorbent stability
Solution Approach 2:
The patent implements rapid cyclic operation with cycle durations of 1-600 seconds, repeatedly alternating between adsorption and regeneration phases. This periodic action allows the adsorbent to be continuously regenerated at moderate temperatures, preventing cumulative thermal damage while maintaining consistent dehydration performance over time
2Quantity of substance
If large molecular sieve adsorbent beds are used for natural gas dehydration, then dehydration capacity is improved, but equipment size, weight, and capital investment increase
Solution Approach 1:
The patent transitions from static, large-scale adsorbent beds to dynamic, rapidly cycled compact beds. By implementing rapid cyclic operation with multiple beds alternating between adsorption and regeneration, the system achieves high dehydration capacity with significantly reduced bed sizes and weights compared to conventional continuous operation systems
Solution Approach 2:
The patent divides the dehydration system into multiple smaller adsorbent beds that operate in sequence rather than one large bed. This segmentation allows parallel operation of adsorption and regeneration processes, maintaining overall dehydration capacity while reducing the size and weight of individual equipment components
3Loss of substance
If high-temperature purge gas is used to minimize regeneration gas volume, then gas handling cost is reduced, but fired furnace safety concerns and additional safety measures increase operational complexity
Solution Approach 1:
The patent changes the temperature parameter of the purge gas from high temperature (≥500°F) to moderate temperature (200-450°F). This eliminates the need for fired furnaces and associated safety systems while maintaining adequate regeneration effectiveness, thus reducing both regeneration gas volume and safety system complexity
Solution Approach 2:
The patent extracts and eliminates the fired furnace component from the system by using compression-heated purge gas instead of combustion-heated gas. This removal of the hazardous heating source eliminates the need for additional safety measures and complexity associated with high-temperature fire safety systems
4Reliability
If compression heating is used to generate purge stream, then fired furnaces are eliminated improving safety, but energy consumption increases
Solution Approach 1:
The patent uses the feed gas itself as the purge gas, which is compressed and heated by the compression process. The compression heating serves dual purposes: preparing the purge gas for regeneration and providing the necessary temperature elevation without external fuel combustion. This self-service approach improves safety by eliminating fired furnaces while using readily available process resources
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 achieves efficient dehydration with reduced equipment footprint, weight, and operational costs, while enhancing safety by eliminating high-temperature heat sources and minimizing adsorbent degradation, allowing for more flexible adsorbent material selection and lower greenhouse gas emissions.
Implementation Method 1
Gas separation is useful in many industries and can typically be accomplished by flowing a mixture of gases over an adsorbent material that preferentially adsorbs one or more gas components
Implementation Method 2
a purge stream at temperatures below 450°F (232.2°C), generated by compression
Data Source
AI summary
Provided are apparatus and systems for performing a swing adsorption process. This swing adsorption process may involve passing streams through adsorbent bed units to remove contaminants, such as water, from the stream. As part of the process, the adsorbent bed unit is purged with a purge stream that is provided at a temperature less than 450° F. The de-contaminated stream may be used with a liquefied natural gas (LNG) plant or other subsequent process requiring a de-contaminated stream. The swing adsorption process may involve a combined TSA and PSA process, which is utilized to remove contaminants from the feed stream.