Methanol Synthesis Using Raw Methanol for CO2 Purification
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Solution Overview
Problem
Existing methanol production processes emit significant carbon dioxide and rely on fossil fuels, necessitating a more sustainable and efficient method to utilize carbon dioxide as a carbon source.
Innovation Solution
A process that purifies crude carbon dioxide using raw methanol as an absorption liquid in a scrubbing column, followed by a methanol synthesis cycle with a catalyst bed and isothermal reactor, effectively removing impurities and producing methanol from purified carbon dioxide and hydrogen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional steam reforming or partial oxidation is used to produce synthesis gas from fossil fuels, then methanol production is achieved, but carbon dioxide emissions are released
Solution Approach 1:
The invention converts carbon dioxide, previously a harmful emission, into a useful carbon source for methanol synthesis. By using CO2 from flue gases or other sources as feedstock instead of fossil fuels, the process transforms a waste product into a valuable raw material, achieving both methanol production and CO2 utilization.
Solution Approach 2:
The invention changes the chemical composition parameters of the synthesis gas by using CO2 and H2 in specific ratios (typically CO2:H2 = 1:3 to 1:4 molar ratio) instead of conventional CO and H2 mixtures. This parameter change enables methanol synthesis from renewable or waste carbon sources rather than fossil fuels.
2Object-affected harmful factors
If carbon dioxide is used as carbon source mixed with hydrogen from water electrolysis, then climate change is limited, but synthesis gas production requires additional processing steps
Solution Approach 1:
The invention extracts and removes impurities from carbon dioxide streams before using them in methanol synthesis. The purification process eliminates catalyst poisons and unwanted components, simplifying downstream processing and protecting the methanol synthesis catalyst from deactivation.
Solution Approach 2:
The invention performs preliminary purification of carbon dioxide streams before they enter the methanol synthesis reactor. By removing impurities in advance through absorption, adsorption, or membrane separation, the process prepares the feedstock to meet catalyst requirements, avoiding the need for complex downstream purification.
3Manufacturing precision
If crude methanol stream is used as absorption liquid for purifying carbon dioxide stream, then purification efficiency is enhanced, but additional processing of crude methanol is required
Solution Approach 1:
The invention makes the crude methanol stream serve multiple functions: it acts as the absorption liquid for CO2 purification, and subsequently as feedstock for methanol synthesis after removing absorbed impurities. This multi-functionality eliminates the need for separate purification agents and integrates the purification and synthesis processes.
Solution Approach 2:
The invention merges the CO2 purification process with the methanol production process by using crude methanol as the absorption medium. The two processes are combined into a single integrated system where the output of one becomes the input of the other, eliminating separate processing units.
4Ease of operation
If scrubbing column is operated at higher pressure between 50 and 100 bar, then pure carbon dioxide can be fed into methanol synthesis cycle without further compression, but energy consumption increases
Solution Approach 1:
The invention performs preliminary compression of the carbon dioxide stream to synthesis pressure (50-100 bar) during the absorption process itself. By conducting the scrubbing operation at high pressure, the CO2 is already compressed when leaving the absorber, eliminating the need for separate compression steps and reducing total energy consumption.
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 method reduces carbon dioxide emissions and enhances the efficiency of methanol production by effectively purifying carbon dioxide, maintaining catalyst performance, and optimizing the methanol synthesis process.
Implementation Method 1
the purification of the crude carbon dioxide stream is carried out absorptively and using the crude methanol stream or a portion thereof as the absorption liquid
Implementation Method 2
a methanol synthesis cycle with a catalyst bed and isothermal reactor, effectively removing impurities and producing methanol from purified carbon dioxide and hydrogen
Implementation Method 3
a methanol synthesis cycle with a catalyst bed and isothermal reactor
Data Source
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AI summary
A process (100, 200) for the production of methanol is proposed, comprising the purification of a crude carbon dioxide stream (103) to obtain a pure carbon dioxide stream (104), the feeding of the pure carbon dioxide stream (104) into a methanol synthesis cycle, and the discharge of a crude methanol stream (111) from the methanol synthesis cycle, wherein the purification of the crude carbon dioxide stream (103) is carried out absorptively using the crude methanol stream (111) or a portion (111a) thereof as the absorbent. A corresponding plant is also proposed.