Low-Pressure Liquid CO2 Production by Expansion Cooling
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Solution Overview
Problem
Current methods for carbon dioxide (CO2) disposal require high-pressure pipelines for transporting CO2 as a supercritical fluid, which is costly and impractical for offshore oil fields, necessitating the development of a method to produce liquid CO2 for easier and more economical delivery.
Innovation Solution
A system and method to produce low-pressure liquid CO2 from a high-pressure CO2 stream, involving cooling and expansion processes using heat exchangers and expanders, followed by separation to achieve a high-purity liquid CO2 with reduced oxygen, nitrogen, and noble gas concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CO2 is transported as a supercritical fluid at high pressure (100-250 bar) through pipelines, then CO2 can be delivered for sequestration or EOR, but the capital expenditure for high-pressure pipelines becomes prohibitively expensive
Solution Approach 1:
The patent changes the pressure parameter of CO2 from high pressure (100-250 bar) to low pressure (6-30 bar) by producing liquid CO2 directly at low pressure through controlled expansion and cooling processes, eliminating the need for high-pressure pipeline infrastructure
Solution Approach 2:
The patent utilizes phase transition of CO2 from supercritical fluid to liquid state through controlled expansion and cooling, enabling CO2 to be transported in liquid form at low pressures which significantly reduces pipeline infrastructure requirements and costs
2Quantity of substance
If CO2 is produced as a high pressure stream at near ambient temperature from power production, then CO2 capture is achieved, but the CO2 cannot be easily delivered to offshore oil fields without extensive pipeline networks
Solution Approach 1:
The patent applies phase transition by cooling and expanding the high-pressure CO2 stream to produce liquid CO2 at low pressure, transforming it into a form that can be easily transported to offshore facilities without requiring extensive high-pressure pipeline networks
Solution Approach 2:
The patent changes both pressure and temperature parameters of the CO2 stream through expansion and cooling processes, converting high-pressure near-ambient temperature CO2 into low-pressure liquid CO2 suitable for economical delivery
3Ease of operation
If CO2 is cooled to low temperatures and expanded to form liquid CO2, then liquid CO2 can be produced for easier delivery, but the CO2 stream must be purified to achieve low levels of oxygen, nitrogen, and noble gases
Solution Approach 1:
The patent performs preliminary purification of the CO2 stream before the cooling and expansion processes, removing oxygen, nitrogen, and noble gases in advance to prevent their concentration in the final liquid CO2 product and avoid safety issues with explosive mixtures
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
Enables the production of high-purity liquid CO2 at lower pressures, reducing transportation costs and making it feasible for offshore applications by achieving a low oxygen and inert gas content, thus facilitating efficient CO2 delivery and utilization.
Implementation Method 1
cooling the high pressure CO2 stream to a temperature of about 5 °C or less by passing the high pressure CO2 stream through a heat exchanger in a heat exchange relationship with the cooling stream
Implementation Method 2
expanding the cooled high pressure CO2 stream so as to form a low pressure CO2 stream
Implementation Method 3
passing the low pressure CO2 stream through a separator effective to separate a vapor stream therefrom and provide the low pressure liquid CO2 stream
Data Source
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AI summary
The present disclosure relates to a method for production of a low pressure liquid carbon dioxide (CO2) stream, the method comprising providing a high pressure CO2 containing stream at a pressure of about 60 bar (60 MPa) or greater; dividing the high pressure CO2 containing stream into a bulk portion and a cooling portion; expanding the cooling portion of the high pressure CO2 containing stream to reduce the temperature thereof to about 0 °C or less; cooling the bulk portion of the high pressure CO2 containing stream to a temperature of about 5 °C or less by passing the bulk portion of the high pressure CO2 containing stream through a heat exchanger against the expanded cooling portion of the high pressure CO2 containing stream; and expanding the cooled, bulk portion of the high pressure CO2 containing stream to a pressure that is about 30 bar (3 MPa) or less but is greater than the triple point pressure of CO2 so as to form the low pressure liquid CO2 stream.