Methanation System Pressure Optimization
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Solution Overview
Problem
Existing methods for producing synthetic natural gas (SNG) on an industrial scale face inefficiencies in energy usage due to the need for compression to achieve pipeline pressures, often resulting in higher energy consumption and operational costs.
Innovation Solution
The process involves setting the target pressure before the main reaction zone or in the post-reaction zone using an additional compressor, accounting for the sum of the target pressure and pressure losses throughout the methanation system, which allows for more favorable compression ratios and energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compression to pipeline pressure is performed after methanation, then the SNG can be injected into the pipeline system, but energy consumption increases due to higher compression ratios required
Solution Approach 1:
The patent applies preliminary action by performing compression before the methanation reaction zone instead of after. The synthesis gas is compressed to a pressure higher than the final pipeline pressure requirement, and then the exothermic methanation reaction further increases the pressure. This preliminary compression allows the system to achieve pipeline injection capability while utilizing the reaction heat to maintain pressure, thereby reducing the energy consumption of compressors.
Solution Approach 2:
The patent converts the typically harmful effect of pressure loss during methanation into a beneficial pressure increase. By positioning the compression upstream and utilizing the exothermic nature of the methanation reaction, the temperature increase from compression is converted into additional pressure through the reaction process itself, rather than requiring additional compression energy downstream.
2Use of energy by moving object
If compression is performed upstream to account for pressure losses, then energy savings are achieved through favorable compression ratios, but the system complexity increases due to additional compressors
Solution Approach 1:
The patent applies universality by designing the compression system to serve multiple functions simultaneously. The upstream compressor not only compresses the synthesis gas to the required pressure but also preheats the gas through the exothermic methanation reaction. This multi-functionality reduces the need for separate heating systems and minimizes overall system complexity despite the unconventional compression positioning.
3Use of energy by moving object
If the target pressure is set before the main reaction zone, then the compression ratio becomes more favorable for energy efficiency, but the pressure losses in the methanation system must be precisely accounted for
Solution Approach 1:
The patent applies feedback by continuously monitoring and adjusting the compression pressure based on the actual pressure losses observed in the methanation system. The system measures the pressure at various points and uses this information to optimize the upstream compression pressure, ensuring it is high enough to account for losses but not excessively high to waste energy. This feedback mechanism achieves precise pressure control without requiring overly complex calculations.
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 leads to significant energy savings by utilizing the temperature increase from compression to heat the synthesis gas and reduces the overall energy requirements for compressors, resulting in a more energy-efficient production of SNG suitable for pipeline injection.
Implementation Method 1
compression using an additional compressor upstream of the main reaction zone and/or upstream or in the post-reaction zone of a methanation system
Implementation Method 2
utilizing the temperature increase from compression to heat the synthesis gas
Implementation Method 3
catalytic methane synthesis by hydrogenation of carbon monoxide (CO) with hydrogen (H2) dates back to the work of Sabatier and Senderens from 1902
Implementation Method 4
catalytic methane synthesis by hydrogenation of carbon monoxide (CO) with hydrogen (H2)
Implementation Method 5
Both of the aforementioned reactions for methane formation are highly exothermic
Data Source
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AI summary
The invention relates to a method for producing substitute natural gas (SNG) which is supplied into a downstream pipeline system, at the feeding pressure and in an energy efficient manner. To this end, a syngas containing carbon monoxide and hydrogen is converted into a methane-rich product gas in a main reaction zone and a post-reaction zone by means of multi-stage catalytic methanation, the target pressure being adjusted by compression before the main reaction zone and/or before or in the post-reaction zone.