Method of removing solids by modifying a liquid level in a distillation tower
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Solution Overview
Problem
Conventional distillation methods face challenges in separating carbon dioxide from methane at cryogenic temperatures, leading to solidification issues and accumulation of solids in the controlled freeze zone section, which can interfere with the separation process and disrupt the operation of cryogenic distillation towers.
Innovation Solution
A method and device that maintain a controlled freeze zone section in a distillation tower, incorporating a melt tray assembly to form and melt solids, where the liquid level is raised to disengage accumulated solids and then lowered once the temperature stabilizes, preventing adhesion and ensuring continuous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cryogenic distillation is used to separate CO2 from methane, then separation efficiency is improved, but solidification of CO2 occurs leading to accumulation of solids
Solution Approach 1:
The patent converts the harmful solidification of CO2 into a beneficial separation mechanism by designing a controlled freeze zone where CO2 selectively freezes out of the methane stream. The solid CO2 that would normally be a problem is instead utilized as the separation mechanism itself, allowing high-purity methane to be obtained while CO2 is removed as solid particles.
Solution Approach 2:
The patent employs phase transition of CO2 from gas to solid in the controlled freeze zone. By maintaining temperatures below the CO2 sublimation point but above the methane freezing point, CO2 undergoes phase change to solid form while methane remains gaseous, enabling separation based on differential phase behavior.
2Manufacturing precision
If solids accumulate on mechanical components in the controlled freeze zone, then separation process is disrupted, but operating conditions required for separation cause solid formation
Solution Approach 1:
The patent incorporates a melt tray assembly positioned below the controlled freeze zone that proactively melts solid CO2 before it can accumulate and interfere with mechanical components. This preliminary melting action prevents solid buildup on trays and mechanical parts, ensuring continuous operation while maintaining separation quality.
Solution Approach 2:
The melt tray assembly acts as an intermediary between the controlled freeze zone and the mechanical components. It provides a controlled environment where solid CO2 can be safely melted and removed, protecting mechanical components from direct contact with accumulating solids while maintaining the cryogenic separation process.
3Reliability
If liquid level is raised to remove accumulated solids, then solids are disengaged, but energy consumption increases
Solution Approach 1:
The system uses the existing cold liquid stream from the distillation process itself to melt the solid CO2 accumulation, rather than introducing external heat sources. The cold liquid, which would otherwise be wasted, is utilized to absorb heat from the solids and facilitate melting, making the solids removal process self-service and energy-efficient.
Solution Approach 2:
The patent changes the temperature parameter of the liquid stream by allowing it to absorb heat as it passes through the melt tray assembly. This parameter change enables the liquid to transition from a colder state to a slightly warmer state, facilitating the melting of solids without requiring additional energy input to the system.
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
Effectively prevents the accumulation of solids on the surface of the controlled freeze zone section, ensuring proper separation of methane from contaminants and maintaining the integrity of the distillation process by disengaging and melting accumulated solids through controlled liquid level adjustments.
Implementation Method 1
raising a liquid level of a liquid in the melt tray assembly when the solids accumulate on a mechanical component in the controlled freeze zone section; raising a liquid temperature of the liquid while raising the liquid level
Data Source
AI summary
The present disclosure provides a method of separating a feed stream in a distillation tower. The method includes maintaining a controlled freeze zone section in a distillation tower; maintaining a melt tray assembly within the controlled freeze zone section that operates at a temperature and pressure at which solid melts; forming solids in a controlled freeze zone section; raising a liquid level of a liquid in the melt tray assembly when the solids accumulate on a mechanical component in the controlled freeze zone section; raising a liquid temperature of the liquid while raising the liquid level; and lowering the liquid level after at least one of (a) a predetermined time period has passed and (b) an alternative temperature of the mechanical component is within an expected temperature range of a baseline temperature of the mechanical component.