Multi-Stage Methanation for SNG Production Efficiency
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Solution Overview
Problem
Existing coal gasification processes for producing synthetic gas (SNG) are inefficient and costly due to high auxiliary power and water requirements, limiting the utilization of low-grade coal reserves.
Innovation Solution
A system and method for producing SNG that includes gasifying a carbonaceous feedstock, purifying the raw syngas, and using a multi-stage methanation process to increase methane concentration, thereby reducing auxiliary power consumption and water usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional coal gasification processes are used to produce SNG, then SNG can be produced from high rank coals, but the processes are inefficient and expensive when processing low grade coal due to high auxiliary power and water requirements
Solution Approach 1:
The patent segments the methanation process into multiple stages (first methanator, second methanator, etc.) with intermediate mixing points. This segmentation allows for optimized heat and mass transfer at each stage, improving overall conversion efficiency and reducing the auxiliary power needed for compression and heating operations.
Solution Approach 2:
The patent combines the methanation process with syngas purification and coal gasification in an integrated system. By merging these processes, the system utilizes internal heat and material flows more efficiently, reducing the external power and water inputs required for separate operations.
2Productivity
If conventional coal gasification processes are used to produce SNG, then SNG can be produced from high rank coals, but the processes are inefficient and expensive when processing low grade coal due to high water requirements
Solution Approach 1:
The patent recovers and recycles water within the system by condensing moisture from the syngas stream and returning it to the process. This recovery approach reduces the net water consumption while maintaining the necessary humidity for efficient gasification and methanation reactions.
Solution Approach 2:
The patent utilizes phase transitions of water (vaporization during gasification, condensation during cooling) to manage water requirements. By controlling these phase changes, the system optimizes water usage and reduces the quantity of process water needed while maintaining reaction efficiency.
3Adaptability or versatility
If low grade coal reserves are utilized through SNG production, then abundant energy sources can be deployed, but the cost escalates due to high auxiliary power and water requirements
Solution Approach 1:
The patent changes operating parameters (temperature, pressure, gas composition ratios) across multiple methanation stages to optimize conversion of low grade coal to SNG. These parameter adjustments improve reaction efficiency and reduce the auxiliary power and water inputs needed, thereby lowering production costs.
Solution Approach 2:
The patent maintains continuous operation of the gasification and methanation processes with steady feedstock input and product output. This continuity eliminates startup/shutdown losses and optimizes the utilization of low grade coal, reducing the cost per unit of SNG produced while maintaining adaptability to various coal types.
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 approach enhances the efficiency of SNG production by lowering auxiliary power and water requirements, making it more economical to deploy SNG generation systems and utilize low-grade coal reserves effectively.
Implementation Method 1
gasifying a feedstock within a gasifier to provide a raw syngas
Implementation Method 2
A first portion of the treated syngas can be converted into a first effluent in a first methanator
Data Source
AI summary
Systems and methods for processing a hydrocarbon are provided. The method can include gasifying a feedstock within a gasifier to provide a raw syngas. The raw syngas can be processed within a purification system to provide a treated syngas. A first portion of the treated syngas can be converted into a first effluent in a first methanator. The first effluent can be mixed with a second portion of the treated syngas to provide a first mixed effluent. The first mixed effluent can be converted into a second effluent in a second methanator. The second effluent can be mixed with a third portion of the treated syngas to provide a second mixed effluent. The second mixed effluent can be converted into a third effluent in a third methanator.