Blue Methanol Production with CO2 Capture and Off-Gas Recycling
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Solution Overview
Problem
Current methanol production systems result in high CO2 emissions and inefficient use of off-gas streams, which are rich in hydrocarbons, contradicting industry goals of reducing greenhouse gas emissions and increasing energy efficiency.
Innovation Solution
Incorporating a shift section and a CO2 removal section into the methanol production system to capture and utilize CO2, and reintroducing a portion of the off-gas stream as an alternative hydrocarbon feed, thereby reducing CO2 emissions and enhancing energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If current methanol production system layouts are used, then methanol production is achieved, but CO2 emissions are high
Solution Approach 1:
The patent extracts CO2 from the purge gas stream using a CO2 removal section that separates CO2 from the gas mixture. This extracted CO2 can then be captured, stored, or utilized elsewhere, directly reducing CO2 emissions while maintaining methanol production efficiency.
Solution Approach 2:
Instead of discarding the CO2-containing purge gas as waste, the patent recovers and utilizes it through the CO2 removal section. The recovered CO2 is either stored for future use, utilized in other chemical processes, or captured for storage, transforming a harmful emission into a valuable resource.
2Loss of energy
If current system layouts are used, then methanol production is achieved, but off-gas is inefficiently used
Solution Approach 1:
The patent makes the off-gas stream multi-functional by reintroducing it to the methanol synthesis production line as an alternative or additional hydrocarbon feed. This single stream serves multiple purposes: it acts as a fuel source, a carbon source, and an energy carrier, significantly improving energy efficiency while supporting continued methanol production.
Solution Approach 2:
The system serves itself by recycling the off-gas stream back into the production process. The off-gas, which would otherwise be wasted, is reused as feedstock for the methanol synthesis, creating a self-sustaining loop that improves energy efficiency without requiring external inputs.
3Quantity of substance
If purge gas is separated into hydrogen-rich and off-gas streams, then some resource recovery is achieved, but CO2 emission remains high
Solution Approach 1:
The patent segments the purge gas stream into distinct components: a hydrogen-rich stream that is reintroduced to the methanol synthesis line, and an off-gas stream that is separated and utilized as an alternative hydrocarbon feed. This segmentation allows each component to be optimized for its specific use, maximizing resource recovery while minimizing CO2 emissions.
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
Significantly reduces CO2 emissions from methanol production by capturing and utilizing CO2, and improves energy efficiency by recycling off-gas streams within the production process.
Implementation Method 1
a shift section (E) arranged to receive at least a portion of said purge gas stream, at least a portion of said third synthesis gas stream and optionally an additional steam feed, and provide a shifted gas stream
Implementation Method 2
a CO2 removal section (F) arranged to receive at least a portion of the shifted gas stream and provide a CO2-rich gas stream and a first CO2-depleted gas stream
Implementation Method 3
a reformer section (A) arranged to receive said hydrocarbon feed, said steam feed and, where present, said oxygen feed, and to provide a first synthesis gas stream
Implementation Method 4
a cooling train (B), arranged to receive at least a portion of the first synthesis gas stream, and provide a second synthesis gas stream and a third synthesis gas stream
Implementation Method 5
a methanol synthesis section (C) arranged to receive at least a portion of the second synthesis gas stream, optionally in admixture with a hydrogen-rich stream, and to provide a raw methanol stream and a purge gas stream
Data Source
AI summary
A system and a process for producing blue methanol are provided, where blue methanol is understood as methanol produced under conditions limiting the emission of CO2. The system comprises a shift section, a CO2 removal section and in a preferred embodiment also a hydrogen recovery section, arranged downstream a methanol synthesis section.