Single Column Methanol Purification with Side Draw
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Solution Overview
Problem
Existing methanol production processes using single column purification systems cannot produce pure methanol meeting Grade A or AA specifications economically, especially with high ethanol content in conventional synthesis gases, leading to high investment costs and limited applications.
Innovation Solution
A process integrating a side draw in a single distillation column for methanol production from carbon dioxide-rich synthesis gas, eliminating the need for an upstream pre-run column and reducing capital costs by using a single distillation column for purification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a two or three stage column arrangement is used for methanol purification, then pure methanol meeting Grade AA specifications can be produced, but investment costs for columns, evaporators, condensers, instrumentation and other related costs increase significantly
Solution Approach 1:
The invention segments the purification function within a single column by implementing multiple side draws at different heights. Each side draw extracts a specific fraction (light ends, pure methanol, heavy ends) based on the vertical concentration gradient of impurities, replacing the need for multiple sequential columns while maintaining Grade AA purity specifications.
Solution Approach 2:
The invention transitions from a sequential temporal separation approach (multiple columns in series) to a spatial parallel separation approach (multiple side draws at different vertical positions). This dimensional change allows simultaneous extraction of different fractions in one column, reducing overall system complexity while achieving the same purification goal.
2Device complexity
If a single column purification system is used for conventional synthesis gases with high ethanol content, then investment costs are reduced, but it is not possible to produce pure methanol of Grade A or AA specifications
Solution Approach 1:
The invention applies local quality by creating different functional zones within the single column through side draws at specific heights. Each side draw location is optimized to capture fractions with specific impurity profiles, allowing the column to perform multiple separation functions simultaneously and achieve Grade AA purity despite the simplified single-column configuration.
Solution Approach 2:
The invention changes the operational parameters of the single column system by implementing multiple side draws at different positions with different flow rates. This parameter optimization allows the system to handle high ethanol content synthesis gases effectively, achieving both cost reduction and high purity output by tuning the extraction points and rates.
3Manufacturing precision
If a two-column methanol purification system is used, then pure methanol can be produced, but investment costs for columns, evaporators, condensers and instrumentation increase
Solution Approach 1:
The invention merges the functions of multiple columns (pre-run column for light ends removal and product column for final purification) into a single integrated column system. The multiple side draws perform the combined separation tasks that would otherwise require sequential columns, reducing capital investment in columns, evaporators, condensers, and instrumentation while maintaining Grade AA purity.
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
The process achieves pure methanol production meeting Grade AA specifications without an upstream pre-run column, significantly lowering investment costs and maintaining product quality by effectively separating methanol from byproducts in a single column.
Implementation Method 1
separating the crude methanol stream by distillation in the distillation column
Implementation Method 2
introducing the liquid crude methanol stream into a flash tank, discharging from the flash tank a liquid depressurized crude methanol stream, depleted in synthesis gas components
Data Source
AI summary
Provided is a process for producing pure methanol from carbon dioxide-rich synthesis gas, the process including the following steps: at least partially reacting the carbon dioxide rich synthesis gas in a methanol synthesis unit, discharging a liquid crude methanol stream from the methanol synthesis unit, introducing the liquid crude methanol stream into a flash tank, discharging from the flash tank a liquid depressurized crude methanol stream as a bottoms product and a gaseous overhead product stream having synthesis gas components, introducing the liquid depressurized crude methanol stream into a distillation apparatus having of a single distillation column, separating the crude methanol stream in the distillation column, discharging an overhead product stream via an overhead product outlet, discharging a bottoms product stream via the bottoms product outlet, and discharging a pure methanol product stream via a first side draw.