CO2 Quenching in Underground Coal Formations for Contaminant Containment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing underground coal gasification (UCG) processes face challenges in managing groundwater contamination and contaminant escape from depleted panels, as well as inefficiencies in sequestering process fluids like carbon dioxide due to limited access and permeability in carbonaceous formations.
Innovation Solution
The use of carbon dioxide as a process fluid to cool and quench UCG reaction regions, combined with controlled injection and compression to sequester contaminants and form a low-permeability cocoon, maintaining pressure gradients to inhibit further reactions and promote deeper fluid penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water is used to cool UCG reaction regions, then cooling effect is achieved, but groundwater contamination and contaminant escape occur
Solution Approach 1:
The patent introduces carbon dioxide as an intermediary cooling medium instead of water. The CO2 is injected into the UCG reaction region, absorbs heat, and then sequestered in depleted panels or injected into formation formations. This intermediary approach achieves the required cooling effect while avoiding the harmful groundwater contamination associated with water-based cooling systems.
Solution Approach 2:
The patent converts the harmful effect of heat in UCG reaction regions into a beneficial process by using CO2 injection for both cooling and carbon sequestration. The heat that would otherwise cause contamination is utilized to drive the CO2 injection and sequestration process, transforming a harmful thermal condition into a beneficial mechanism for contaminant removal and carbon storage.
2Quantity of substance
If process fluids are injected into carbonaceous formations, then carbon dioxide sequestration is achieved, but limited access and permeability restrict effectiveness
Solution Approach 1:
The patent applies preliminary action by first creating depleted panels through controlled gasification before injecting CO2 for sequestration. These depleted panels are prepared in advance with optimized permeability and porosity, serving as ideal storage zones that enhance CO2 injectivity and sequestration effectiveness. The preliminary depletion process modifies the formation properties to facilitate subsequent successful CO2 injection.
Solution Approach 2:
The patent implements local quality by creating specific zones (depleted panels) with enhanced permeability and porosity in selected areas of the carbonaceous formation. Rather than requiring the entire formation to have optimal properties, the method focuses on developing localized regions with improved characteristics that are specifically suited for CO2 sequestration, while leaving other areas unchanged.
3Reliability
If pressure gradients are maintained to inhibit reactions, then contaminant escape is prevented, but energy consumption increases
Solution Approach 1:
The patent applies self-service by utilizing the natural pressure gradients and thermal conditions already present in the UCG system to drive the CO2 injection and sequestration process. The system leverages its own operational parameters (pressure differentials, temperature gradients) to achieve contaminant containment and carbon sequestration without requiring additional external energy input, making the process self-sustaining.
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 removes contaminants, cools UCG reaction regions to ambient temperatures, and enhances carbon dioxide sequestration by increasing permeability and adsorption, reducing the risk of groundwater contamination and enhancing energy efficiency.
Implementation Method 1
The process fluids can be used to cool UCG reaction regions
Implementation Method 2
maintaining pressure gradients to inhibit further reactions and promote deeper fluid penetration
Implementation Method 3
enhances carbon dioxide sequestration by increasing permeability and adsorption
Data Source
AI summary
Methods and systems for quenching an underground carbonaceous formation with carbon and/or sequestering carbon within an underground carbonaceous formation are disclosed herein. In some embodiments, a representative coal gasification system can comprise (i) an injection conduit extending from a ground surface to an underground coal gasification (UCG) reaction region of a coal seam, (ii) a production conduit extending from a first underground region toward the ground surface, and (iii) an injection well fluidically coupled to a source of process fluid and extending toward a second underground region. The second underground region is laterally spaced apart from the first underground region by an adjacent formation having a hydraulic resistance higher than that of a first hydraulic resistance and a second hydraulic resistance.