Method and system of modifying a liquid level during start-up operations
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Solution Overview
Problem
The accumulation of solids in the controlled freeze zone section of a distillation tower during start-up due to insufficient liquid in the melt tray assembly, which disrupts the separation of methane from contaminants, particularly when the feed stream contains less than 20% contaminants.
Innovation Solution
A method and system that involves operating a controlled freeze zone section in a distillation tower, maintaining a melt tray assembly, and introducing a second contaminant to accumulate liquid until a predetermined level is reached, ensuring the liquid comprises the second contaminant to prevent solid accumulation and facilitate effective separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the feed stream contains less than 20% contaminants during start-up, then the separation process can operate with lower contaminant load, but insufficient liquid accumulates in the melt tray assembly causing solid accumulation that disrupts separation
Solution Approach 1:
The patent introduces a second contaminant into the melt tray assembly before normal operation begins, pre-accumulating sufficient liquid to prevent solid accumulation during start-up. This preliminary action ensures the melt tray has adequate liquid inventory before the feed stream with less than 20% contaminants is processed, thereby maintaining reliable separation operation.
Solution Approach 2:
The second contaminant acts as an intermediary substance to provide the necessary liquid in the melt tray assembly during start-up conditions. By introducing this intermediate substance, the system bridges the gap between insufficient natural liquid accumulation and the required liquid level for reliable solid melting and separation operation.
2Temperature
If conventional distillation is used to separate CO2 from methane, then the process can operate at higher temperatures, but CO2 solidifies and accumulates in the controlled freeze zone section disrupting operation
Solution Approach 1:
The patent utilizes phase transitions by introducing a second contaminant that modifies the freezing behavior of CO2 in the melt tray assembly. This causes CO2 to transition from solid to liquid phase at operating temperatures, preventing solid accumulation and enabling continuous distillation operation without temperature reduction.
Solution Approach 2:
The second contaminant serves as an intermediary that interferes with CO2 crystallization in the melt tray assembly. This intermediate substance prevents direct solidification of CO2 by forming eutectic mixtures or altering freezing points, thereby eliminating the harmful solid accumulation effect while maintaining conventional distillation temperatures.
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
Ensures sufficient liquid accumulation in the melt tray assembly during start-up, preventing solid accumulation and maintaining proper operation and separation efficiency of methane from contaminants.
Implementation Method 1
accumulating a liquid in the melt tray assembly until the liquid is at a predetermined liquid level in the controlled freeze zone section, by: feeding a second contaminant to the controlled freeze zone section; and adding the second contaminant to the melt tray assembly
Implementation Method 2
a controlled freeze zone section in a distillation tower that separates a feed stream at a temperature and pressure at which the feed stream forms a solid in the controlled freeze zone section
Data Source
AI summary
The present disclosure provides a method for separating a feed stream in a distillation tower. The method includes operating a controlled freeze zone section in a distillation tower that separates a feed stream at a temperature and pressure at which the feed stream forms a solid in the controlled freeze zone section, wherein the feed stream includes a first contaminant; maintaining a melt tray assembly in the controlled freeze zone section; introducing the feed stream to the controlled freeze zone section; and accumulating a liquid in the melt tray assembly until the liquid is at a predetermined liquid level in the controlled freeze zone section, by: feeding a second contaminant to the controlled freeze zone section; and adding the second contaminant to the melt tray assembly, wherein the liquid comprises the second contaminant.