Deep Cooling Gas Separation with Alternating Heat Exchanger Thawing
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Solution Overview
Problem
Existing methods struggle to effectively remove moisture to concentrations of tens of ppm or less from natural gas, flue gas, and synthetic gas, leading to pipe clogging and equipment issues, while current heat exchanger thawing methods are inefficient and result in refrigerant loss or contamination.
Innovation Solution
A target gas separation method using a deep cooling process that involves repeatedly freezing and thawing heat exchangers, utilizing a gas separation device with alternating operations to efficiently separate moisture from these gases, including a first and second heat exchanger, inlet units, and connection pipes with valves to manage gas flow and thawing/freeze cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the heat exchanger is cooled to 0 degrees or less to remove moisture to tens of ppm or less, then moisture removal efficiency is improved, but moisture is frozen on the heat exchange surface causing clogging and requiring complex thawing procedures
Solution Approach 1:
The single heat exchanger is divided into multiple heat exchangers that can operate in alternating cycles. While one heat exchanger is freezing moisture, another is being thawed, and vice versa. This segmentation allows continuous operation without complex manual intervention for thawing, as the system automatically switches between units.
Solution Approach 2:
The heat exchangers operate in periodic alternating cycles of freezing and thawing. Each heat exchanger undergoes repeated cycles where it freezes moisture during its active phase and thaws during its standby phase. This periodic action eliminates the need for complex continuous thawing procedures while maintaining effective moisture removal.
2Ease of operation
If hot water is introduced into the refrigerant space to thaw frozen moisture, then thawing is achieved, but refrigerant is lost or contaminated
Solution Approach 1:
Instead of introducing hot water directly into the refrigerant space, the patent uses the inlet gas itself as an intermediary heating medium. The inlet gas, which is warmer than the frozen heat exchanger, is passed through the heat exchanger to thaw the frozen moisture. This eliminates direct contact between water and refrigerant, preventing refrigerant loss and contamination.
Solution Approach 2:
The inlet gas serves a dual purpose: it is both the feedstock to be processed and the heating medium for thawing the heat exchanger. By utilizing the thermal energy of the inlet gas, the system thaws the heat exchanger without requiring external water introduction, thereby avoiding refrigerant contamination and loss.
3Measurement precision
If multiple stages of adsorption towers are used to remove moisture to tens of ppm or less, then moisture removal efficiency is improved, but device complexity and operational requirements increase
Solution Approach 1:
The patent replaces the mechanical adsorption tower system with a thermal cooling system using heat exchangers. Instead of relying on adsorbent materials and multiple tower stages, the system uses controlled cooling to freeze moisture directly from the gas stream. This substitution achieves the same moisture removal precision with a simpler system configuration.
Solution Approach 2:
The patent utilizes the phase transition of moisture from gas to solid (freezing) to remove it from the inlet gas. By cooling the heat exchanger to appropriate temperatures, moisture condenses and freezes on the heat exchange surface, then is removed during the thawing phase. This phase transition mechanism achieves high moisture removal efficiency without requiring multiple adsorption stages.
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 method achieves efficient moisture removal to low concentrations without refrigerant loss, reducing equipment clogging and thawing time, and maintaining high purity carbon dioxide separation efficiency.
Implementation Method 1
a first heat exchanger configured to cool inlet gas, a second heat exchanger configured to cool inlet gas
Implementation Method 2
when the heat exchanger is cooled to 0 degrees or less, moisture is frozen on a heat exchange surface of the heat exchanger
Implementation Method 3
a first thawing operation of blocking the first gas inlet unit and introducing inlet gas to the second heat exchanger through the second gas inlet unit to thaw the second heat exchanger
Data Source
AI summary
A target gas separation method using a deep cooling process includes a first process operation including a first thawing operation of blocking the first gas inlet unit and introducing inlet gas to the second heat exchanger through the second gas inlet unit to thaw the second heat exchanger and a first freezing operation transferring gas flowing into the second heat exchanger to the first heat exchanger through the second connection pipe to freeze target gas in the first heat exchanger, and a second process operation including a second thawing operation of blocking the second gas inlet unit and introducing inlet gas to the first heat exchanger through the first gas inlet unit to thaw the first heat exchanger and a second freezing operation of transferring gas flowing into the first heat exchanger to the second heat exchanger through the first connection pipe to freeze the target gas in the second heat exchanger, and wherein, after the first process operation is performed for a designated time, the second process operation is performed for another designated time.