Biogas Upgrading via Low-Temperature District Heating
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Solution Overview
Problem
Current biogas upgrading methods are energy-intensive and costly due to the use of steam or superheated water for desorption, leading to high energy consumption and environmental risks.
Innovation Solution
A method and plant for upgrading biogas using an amine-based absorption liquid, where carbon dioxide is absorbed at 1013-2000 hPa and desorbed at pressures above 400 hPa absolute but below 600 hPa absolute, utilizing district heating and a closed system to reduce energy costs and environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If steam or superheated water is used for heating the absorption liquid during desorption, then the desorption efficiency is improved, but the energy consumption and costs increase significantly
Solution Approach 1:
The patent changes the temperature parameter of the heating medium from high temperature (steam/superheated water) to low temperature (district heating, 80-150°C). By adjusting the pressure parameters during desorption to 0.5-2.0 bar absolute, the system achieves effective CO2 removal using lower temperature heating, thus reducing energy consumption while maintaining desorption efficiency
Solution Approach 2:
The patent utilizes the phase transition of water from liquid to vapor during desorption. The absorbed CO2 is removed by heating the absorption liquid to its boiling point under reduced pressure, where the phase change of water provides the necessary heat for desorption, eliminating the need for external steam or superheated water
2Productivity
If steam or superheated water is used for heating the absorption liquid, then the desorption process is effective, but environmental risks and safety concerns increase
Solution Approach 1:
The patent replaces expensive and hazardous steam/superheated water with inexpensive and safe district heating or other low-temperature heat sources. This substitution eliminates the environmental and safety risks associated with high-temperature steam while maintaining effective desorption through the combination of low pressure and moderate temperature heating
3Device complexity
If the absorption liquid is not recirculated in a closed system, then the system is simpler, but the costs and environmental load increase
Solution Approach 1:
The patent implements a closed circulation system where the absorption liquid is continuously recovered and reused. After desorption in the stripping column, the regenerated absorption liquid is cooled and recirculated back to the absorption column, eliminating waste and reducing the need for continuous absorption liquid replacement, thus reducing costs and environmental impact
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 energy consumption and costs by using lower temperature heating, eliminating the need for steam or superheated water, and reduces environmental risks while enabling the reuse and recirculation of the absorption liquid, thereby enhancing the efficiency and safety of the biogas upgrading process.
Implementation Method 1
absorption of carbon dioxide from biogas containing carbon dioxide by means of an absorption liquid, wherein the absorption is carried out at a pressure of 1013-2000 hPa
Implementation Method 2
desorption of carbon dioxide from the absorption liquid containing carbon dioxide, wherein the desorption is carried out at a pressure of above 400 hPa absolute and below 600 hPa absolute
Implementation Method 3
the absorption liquid containing carbon dioxide is heated using district heating during the desorption to at or above its boiling point
Data Source
Figure 1
AI summary
A method for upgrading of biogas containing carbon dioxide comprising absorption of carbon dioxide from biogas containing carbon dioxide by means of an absorption liquid is described. The absorption is carried out at a pressure of 1013-2000 hPa and desorption of carbon dioxide from the absorption liquid containing carbon dioxide is carried out at a pressure of above 300 hPa absolute.