Hydromethanation Reactor Steam Integration
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Solution Overview
Problem
Current hydromethanation processes for producing methane from carbonaceous feedstocks are complex and costly due to inefficient gas recycle loops and steam generation, leading to increased engineering complexity and decreased system efficiency.
Innovation Solution
A process that involves supplying a carbonaceous feedstock, hydromethanation catalyst, steam, and a gas feed stream to a hydromethanation reactor, with heat recovery and steam generation integrated to optimize steam demand and syngas balance, reducing the need for external steam generation and simplifying the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional gasification processes are used to produce methane from carbonaceous feedstocks, then methane can be produced through catalytic methanation of syngas, but the process complexity and cost increase due to multiple separate steps for syngas production, purification, and methane synthesis
Solution Approach 1:
The patent combines the syngas production and methane synthesis steps into a single hydromethanation reactor. Carbonaceous feedstock is converted directly to methane in one reactor through the combined reactions of steam carbon, water-gas shift, CO methanation, and hydro-gasification, eliminating the need for separate syngas production and purification units.
Solution Approach 2:
The hydromethanation reactor performs multiple functions simultaneously: it acts as a gasifier, a shift reactor, a methanation reactor, and a purification unit all in one device. This multi-functional approach reduces the number of separate process units and simplifies the overall process flow.
2Quantity of substance
If external steam generation is used to meet steam demand in hydromethanation, then sufficient steam is provided for the reaction, but system efficiency decreases and engineering complexity increases
Solution Approach 1:
The process generates its own steam internally through the steam carbon reaction and water-gas shift reaction within the hydromethanation reactor. The steam required for the reaction is produced from the carbonaceous feedstock itself, making the system self-sufficient and eliminating the need for external steam generation facilities.
Solution Approach 2:
The patent optimizes the steam carbon reaction conditions to maximize steam generation from the carbonaceous feedstock. By controlling temperature, pressure, and reactant ratios, the process converts carbon and limited water into the required steam and syngas in-situ, changing the parameter of steam source from external to internal generation.
3Reliability
If syngas is withdrawn from the product gases to maintain syngas balance, then the reaction can continue, but carbon monoxide and hydrogen need to be added back, increasing process complexity
Solution Approach 1:
The patent implements a feedback mechanism where the composition of the product gas is continuously monitored, and the syngas feed is automatically adjusted to maintain the optimal H2:CO ratio. This closed-loop control ensures that syngas balance is maintained without requiring complex manual intervention or multiple separate recycle loops.
Solution Approach 2:
The patent uses an intermediary gas stream that combines fresh syngas with recycled product gas to achieve the desired composition. This intermediary mixing approach allows flexible control of the H2:CO ratio and simplifies the gas management system compared to separate recycle loops for each component.
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 the efficiency and reduces the complexity of methane production by optimizing steam and syngas management, leading to a more cost-effective and streamlined process for generating pipeline-quality natural gas.
Implementation Method 1
reacting the carbonaceous feedstock in the presence of carbon monoxide, hydrogen, steam and hydromethanation catalyst to produce a methane-enriched raw product stream
Implementation Method 2
introducing the methane-enriched raw product stream into a heat exchanger to recover heat energy and generate a cooled methane-enriched raw product stream
Implementation Method 3
superheating the steam stream using the heat energy recovered from the methane-enriched raw product stream
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
Implementation Method 7
Hydro-gasification: 2H2+C→CH4
Data Source
AI summary
The present invention relates to processes for preparing gaseous products, and in particular methane, via the hydromethanation of carbonaceous feedstocks in the presence of steam, carbon monoxide, hydrogen and a hydromethanation catalyst.