Heating component to reduce solidification in a cryogenic distillation system
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Solution Overview
Problem
Cryogenic distillation columns face challenges during start-up due to the potential for CO2 solidification outside the freezing section, leading to equipment fouling and malfunction, especially when there are sudden temperature increases and high CO2 concentrations in the overhead stream.
Innovation Solution
Incorporating a heating component to heat the overhead stream and maintain a temperature margin that prevents CO2 solidification, combined with a cooling cycle that includes compression, heat exchange, and pressure reduction to recycle the stream and lower CO2 concentrations to a non-solidifying range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the overhead stream is cooled to condense CO2 for removal, then CO2 separation efficiency is improved, but CO2 solidification occurs outside the freezing section causing equipment fouling
Solution Approach 1:
The heating component applies preliminary heating to the overhead stream before it enters downstream equipment, raising the temperature above the CO2 solidification point. This preliminary action prevents CO2 from solidifying in equipment outside the freezing section, resolving the fouling issue while maintaining the cooling process needed for CO2 separation.
Solution Approach 2:
The system dynamically adjusts the temperature parameter of the overhead stream by applying heat to change its state from a temperature prone to CO2 solidification to a safer temperature range. This parameter change allows the stream to be cooled sufficiently for CO2 condensation while preventing solidification in downstream equipment.
2Reliability
If solidification inhibitors are used during start-up, then CO2 solidification is prevented, but system complexity and operational cost increase
Solution Approach 1:
The invention extracts and removes the need for solidification inhibitors by implementing a heating component that physically prevents CO2 solidification through temperature control. This eliminates the complexity of managing chemical inhibitors and their associated handling, storage, and dosing systems.
Solution Approach 2:
The heating component enables the system to self-regulate and prevent CO2 solidification without requiring external chemical additives. The system uses its own overhead stream as the heating medium, creating a self-service mechanism that simplifies operations during start-up and normal operation.
3Object-affected harmful factors
If the overhead stream temperature is increased to prevent CO2 solidification, then equipment fouling is reduced, but CO2 condensation efficiency decreases
Solution Approach 1:
The system segments the temperature control into different zones: the freezing section maintains low temperatures for CO2 condensation, while the overhead stream receives localized heating before entering downstream equipment. This segmentation allows simultaneous optimization of both condensation efficiency and fouling prevention.
Solution Approach 2:
The heating component acts as an intermediary between the cold overhead stream and the downstream equipment. It temporarily raises the stream temperature to prevent solidification during transport, then the stream can be cooled again for condensation, mediating between the conflicting requirements of fouling prevention and condensation efficiency.
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 effectively reduces the likelihood of CO2 solidification in downstream equipment, preventing fouling and ensuring smooth start-up and operation of the cryogenic distillation column by maintaining the CO2 concentration within a non-solidifying range.
Implementation Method 1
heating the overhead stream via a heating component to form a heated overhead stream. The heated overhead stream may reduce or prevent solidification of the CO2 in the overhead stream
Implementation Method 2
compressing the heated overhead stream via an overhead compressor to produce a high-pressure vapor
Implementation Method 3
reducing pressure and temperature of the high-pressure vapor via a Joule-Thomson (J-T) valve to produce a liquid-vapor stream
Implementation Method 4
flowing the heated overhead stream into a heat exchanger to substantially reduce or prevent solidification
Data Source
AI summary
A method and a system for feeding a feed gas including methane (CH4) and carbon dioxide (CO2) to a cryogenic distillation column are provided herein. The method includes flowing a freeze zone CO2 vapor stream into a freezing section of the column to produce an overhead stream that exits the column. The method includes heating the overhead stream via a heating component to reduce or prevent solidification of the CO2 in the overhead stream.