Hydromethanation Char Gasification for Carbon Utilization
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Solution Overview
Problem
The hydromethanation process faces challenges in fully utilizing the carbon content of the char by-product, leading to energy inefficiencies and increased costs due to the need for catalyst recovery and processing of unconverted carbon.
Innovation Solution
The process involves reacting the unconverted char with oxygen and steam in an oxidation reactor to produce synthesis gas or combustion products, which can be reintegrated into the hydromethanation process, improving carbon utilization and thermal efficiency, and reducing the volume of material for catalyst recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the hydromethanation process is operated to maximize methane production, then the carbon conversion in the reactor is limited to less than 100% (typically 85-95%), but this results in unconverted carbon remaining in the char by-product, leading to energy inefficiency and increased processing costs
Solution Approach 1:
The patent implements a continuous process where char is continuously withdrawn from the hydromethanation reactor and immediately fed into a combustion chamber for gasification. This continuous conversion of unconverted carbon to synthesis gas eliminates energy loss and maintains productive action throughout the entire process, transforming what would be waste material into valuable fuel gas that can be reused in the hydromethanation reactor.
2Reliability
If the char by-product is removed and sent for catalyst recovery, then the catalyst can be recovered and reused, but the volume of material for processing is large and requires significant processing capacity
Solution Approach 1:
The patent extracts and removes the unconverted carbon from the char by-product in the combustion chamber through gasification, converting it to synthesis gas. This leaves behind a reduced volume of processed material that contains the catalyst, making the subsequent catalyst recovery process more efficient and requiring less processing capacity while maintaining reliable catalyst recovery.
3Loss of energy
If an oxidation reactor is added to gasify the char by-product, then carbon utilization is improved and thermal efficiency increases, but the device complexity and capital costs increase
Solution Approach 1:
The patent combines the combustion chamber and gasification processes into an integrated system where the unconverted carbon is continuously converted to synthesis gas and fed back to the hydromethanation reactor. This merging of functions improves thermal efficiency and carbon utilization while avoiding the need for a separate, complex oxidation reactor, thereby reducing overall device complexity and capital costs.
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
This approach enhances carbon utilization, improves thermal efficiency, and lowers operating and capital costs by integrating the oxidation reactor products back into the hydromethanation process, thereby optimizing energy use and reducing waste.
Implementation Method 1
reacting the unconverted char with oxygen and steam in an oxidation reactor to produce synthesis gas or combustion products
Implementation Method 2
reacting the unconverted char with oxygen and steam in an oxidation reactor
Implementation Method 3
reacting the unconverted char with oxygen and steam in an oxidation reactor to produce synthesis gas or combustion products
Implementation Method 4
Steam carbon: C+H2O→CO+H2
Implementation Method 5
Water-gas shift: CO+H2O→H2+CO2
Implementation Method 6
CO Methanation: CO+3H2→CH4+H2O
Data Source
AI summary
The present invention relates generally to processes for hydromethanating a carbonaceous feedstock in a hydromethanation reactor to a methane-enriched raw product stream, and more specifically to processing of solid char by-product removed from the hydromethanation reactor to improve the carbon utilization and thermal efficiency of the overall process and thereby lower the net costs of the end-product pipeline quality substitute natural gas.