Method and system for separating carbon dioxide from flue gas
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Solution Overview
Problem
Existing methods for separating carbon dioxide from flue gas face challenges in preventing the evaporation of carbon dioxide liquid due to temperature differences between streams in the reboiler, leading to inefficiencies and potential losses.
Innovation Solution
The system compresses flue gas, cools it in heat exchangers, separates carbon dioxide rich and lean streams, and directs them into a distillation column, where non-condensable gases are expanded to cool the heat exchangers, while the carbon dioxide liquid is heated and expanded to match temperatures, eliminating the need for a buffer drum and preventing evaporation by ensuring equal or matching temperatures for the purified and cooled carbon dioxide liquids before reintegration into the heat exchanger circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If carbon dioxide liquid from cold side reboiler (0°C) and warm side reboiler (3°C) are mixed in buffer drum, then purification is achieved, but evaporation occurs due to temperature difference
Solution Approach 1:
The patent divides the carbon dioxide liquid stream into two separate temperature streams (cold side at 0°C and warm side at 3°C) that are kept distinct throughout the system. Instead of mixing them in a buffer drum, each stream is separately expanded and cooled to match temperatures before recombination, preventing evaporation while maintaining purification quality.
Solution Approach 2:
The patent applies preliminary cooling action by expanding the warm side carbon dioxide liquid (3°C) before it reaches the mixing point, reducing its temperature to match the cold side stream (0°C). This preliminary temperature matching prevents evaporation that would occur if the warmer stream directly contacted the colder stream in a buffer drum.
2Quantity of substance
If buffer drum with large heat exchanging surface is used, then carbon dioxide liquid collection is achieved, but evaporation risk increases due to heat exchange through surface
Solution Approach 1:
The patent extracts and eliminates the buffer drum component from the system entirely. Instead of using a large heat exchanging surface for liquid collection, the system uses separate expansion and cooling channels that maintain temperature balance without requiring a buffer storage vessel, thereby removing the evaporation pathway through heat exchange surfaces.
Solution Approach 2:
The patent transitions from a spatial buffer storage approach (buffer drum with heat exchanging surface) to a temporal/process-based approach (separate expansion and cooling channels). By changing the dimension of the solution from spatial storage to process sequencing, the system eliminates the need for large heat exchanging surfaces while maintaining effective carbon dioxide liquid collection.
3Stability of the object's composition
If traditional separation system with buffer drum is used, then system stability is achieved, but device complexity and heat exchange surface requirements increase
Solution Approach 1:
The patent merges the functions of the buffer drum and heat exchangers into a streamlined sequence of expansion valves and cooling channels. By combining storage, temperature adjustment, and mixing functions into a compact integrated flow path, the system maintains stability while reducing device complexity and eliminating large heat exchange surface requirements.
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 effectively prevents carbon dioxide evaporation, enhances the efficiency of the separation process, and eliminates the need for large heat exchanging surfaces and buffer drums, thereby improving the overall separation and purification of carbon dioxide from flue gas.
Implementation Method 1
cooling the compressed flue gas in at least a heat exchanger
Implementation Method 2
The non-condensable gas, after expansion in an expansion valve
Implementation Method 3
separating in the distillation column non-condensable gas from carbon dioxide liquid
Implementation Method 4
heating the carbon dioxide liquid (CDL) at a cold side of a reboiler generating a purified carbon dioxide liquid (PCDL)
Implementation Method 5
supplying the expanded carbon dioxide liquid (ECDL) from the heat exchangers to a high-pressure compressor to generate a compressed carbon dioxide vapor (CCDV)
Data Source
AI summary
A method for separating carbon dioxide from flue gas to generate a high purity CO2 stream.