Flash Gas Separator for SNG Production
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Solution Overview
Problem
Existing systems for producing synthetic natural gas (SNG) from low-grade coal are inefficient due to high auxiliary power and water requirements, leading to increased production costs and limited deployment options.
Innovation Solution
The method involves gasifying a carbonaceous feedstock to produce raw syngas, which is cooled and purified using a flash gas separator and saturator, with the methanation condensate being reintroduced to the flash gas separator to generate steam and produce SNG, reducing the need for external power and water through heat transfer and recycling processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a typical SNG production system is used, then SNG can be produced from low grade coal, but high auxiliary power and large quantities of water are required
Solution Approach 1:
The patent combines the syngas cooler and methanator into an integrated system where the cooling process and methanation reaction occur in close proximity, allowing direct utilization of the cooling medium for steam generation that drives the methanation reaction, thereby reducing external power requirements
Solution Approach 2:
The system uses its own process steam from the syngas cooling process to drive the methanation reaction and generate necessary process heat, making the system self-sufficient for thermal energy needs and reducing auxiliary power consumption
2Ease of manufacture
If a typical SNG production system is used, then SNG can be produced from low grade coal, but large quantities of water need to be supplied
Solution Approach 1:
The patent recovers and recycles process water from the SNG production process back into the system, particularly using condensed water from the syngas cooling process to meet water requirements for gasification and other process needs, thereby reducing external water supply requirements
Solution Approach 2:
The patent employs water serving multiple functions within the system - as a gasification agent, as a cooling medium, and as a source of process steam - thereby maximizing water utilization efficiency and reducing the total quantity of water that needs to be supplied from external sources
3Manufacturing precision
If methanation is performed to convert syngas to SNG, then methane concentration increases, but steam generation requires additional water and energy
Solution Approach 1:
The patent converts the heat that would otherwise be wasted during syngas cooling into useful process steam by using the cooling medium to absorb and utilize this thermal energy for steam generation, thereby turning a potentially harmful heat loss into a beneficial resource for the methanation process
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 decreases auxiliary power consumption, capital costs, and operating costs while increasing the methane concentration in SNG, enhancing its heating value and reducing product gas recycle requirements, thereby making SNG production more efficient and economical.
Implementation Method 1
the raw syngas is cooled using a heat transfer medium
Implementation Method 2
the methanation reaction generates steam
Implementation Method 3
incorporating a flash gas separator and saturator to enhance methane concentration
Implementation Method 4
incorporating a flash gas separator and saturator to enhance methane concentration and reduce process water consumption
Data Source
AI summary
Systems and methods for producing synthetic natural gas are provided. The method can include gasifying a carbonaceous feedstock within a gasifier to provide a raw syngas. The raw syngas can be cooled to provide a cooled raw syngas. The cooled raw syngas can be processed in a purification system to provide treated syngas. The purification system can include a flash gas separator in fluid communication with the gasifier and a saturator. The treated syngas can be converted to synthetic natural gas to provide steam, a methanation condensate, and a synthetic natural gas. The methanation condensate can be introduced to the flash gas separator.