Controlled Freezing Zone for Cryogenic CO2 Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cryogenic gas separation systems face challenges in reducing CO2 and H2S content to low levels required for LNG specifications without increasing refrigeration equipment capacity, particularly in highly sour gas streams with CO2 concentrations above 5 mol. percent, which can lead to the formation of solid CO2 disrupting the distillation process.
Innovation Solution
A cryogenic distillation system with a controlled freezing zone that uses a cold liquid reflux to precipitate solid CO2 particles, which are collected and processed separately, reducing the refrigeration requirements and allowing for efficient CO2 removal while maintaining methane purity for downstream liquefaction processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cryogenic distillation is used to separate CO2 from hydrocarbon gas streams, then CO2 removal efficiency is improved, but solid CO2 formation disrupts the distillation process
Solution Approach 1:
The patent extracts solid CO2 particles from the distillation process by introducing a cold liquid spray that precipitates CO2 as solid particles, which are then removed from the system before they can disrupt the distillation operation, allowing continuous stable operation while achieving high CO2 removal efficiency
Solution Approach 2:
The patent changes the physical state parameter of CO2 by controlling temperature and pressure conditions in the cold liquid spray section, transforming CO2 from gaseous phase in the feed stream to solid phase for easy separation, thereby improving removal efficiency while preventing solid formation disruptions in the main distillation column
2Manufacturing precision
If refrigeration capacity is increased to reduce CO2 to LNG specifications, then CO2 removal effectiveness is improved, but energy consumption increases
Solution Approach 1:
The patent uses the hydrocarbon gas stream itself as the refrigerant medium, allowing the process fluid to provide the cooling function rather than requiring external refrigeration equipment, thereby achieving LNG specifications with minimal additional energy consumption
Solution Approach 2:
The cold liquid spray serves multiple functions: it acts as a refrigerant to cool the gas stream, a precipitating agent to form solid CO2 particles, and a separation medium to remove acid gases, eliminating the need for separate refrigeration equipment and reducing energy consumption
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 system effectively reduces CO2 and H2S content to levels acceptable for LNG specifications without increasing refrigeration capacity, enhancing the efficiency of acid gas removal and reducing energy consumption in the cryogenic distillation process.
Implementation Method 1
A cryogenic distillation system with a controlled freezing zone that uses a cold liquid reflux to precipitate solid CO2 particles
Implementation Method 2
Cryogenic gas separation generates a cooled overhead gas stream at moderate pressures
Data Source
AI summary
A system for removing acid gases from a raw gas stream is provided. The system includes a cryogenic distillation tower. The cryogenic distillation tower has a controlled freezing zone that receives a cold liquid spray comprised primarily of methane. The tower receives and then separates the raw gas stream into an overhead methane gas stream and a substantially solid material comprised on carbon dioxide. The system includes a collector tray below the controlled freezing zone. The collector tray receives the substantially solid material as it is precipitated in the controlled freezing zone. The system also has a filter. The filter receives the substantially solid material and then separates it into a solid material comprised primarily of carbon dioxide, and a liquid material comprising methane. The solid material may be warmed as a liquid and sold, while the liquid material is returned to the cryogenic distillation tower.