Glucose Feed pH Control for Selective Ethylene Glycol Production
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Solution Overview
Problem
Existing methods for producing glycols from carbohydrate feeds face challenges in maintaining the stability of the carbohydrate feed under high pH conditions, leading to isomerization of glucose to fructose and reduced yields of ethylene glycol, especially when combined with a retro-Aldol catalyst.
Innovation Solution
A method involving the preparation of a feed solution with a carbohydrate feed, a soluble retro-Aldol catalyst, and an acid to maintain a pH range of 2-6, using a heterogeneous hydrogenation catalyst under hydrogenation conditions to produce ethylene glycol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a retro-Aldol catalyst is combined with carbohydrate feed in a single feed solution, then the process complexity is reduced and productivity is improved, but the carbohydrate feed becomes unstable under high pH conditions leading to glucose isomerization to fructose
Solution Approach 1:
The patent adjusts the pH parameter of the feed solution to a range of 2-6 (acidic to neutral) to prevent glucose isomerization to fructose. This parameter change stabilizes the carbohydrate feed while maintaining catalyst activity, resolving the contradiction between process simplicity and feed stability.
2Productivity
If the pH is increased to enhance retro-Aldol catalyst activity, then the catalytic efficiency is improved, but glucose isomerization to fructose increases reducing ethylene glycol yield
Solution Approach 1:
The patent optimizes the pH parameter to a specific range (2-6) that balances catalyst activity with glucose stability. This parameter optimization ensures high ethylene glycol selectivity while maintaining adequate catalytic efficiency, resolving the contradiction between productivity and manufacturing precision.
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 achieves selective formation of ethylene glycol, high yields, and stable catalyst activity by preventing glucose isomerization to fructose, allowing the use of high-concentration sugar solutions, thus enhancing the economic efficiency of the glycol production process.
Implementation Method 1
each carbon has one attached hydroxyl group or contains an oxygen function that can be readily converted into a hydroxyl. As such, EG and PG can be produced if the C-C bonds are selectively cleaved into C2 and C3 units
Implementation Method 2
The feed solution may be contacted, in a reactor under hydrogenation conditions, with a heterogeneous hydrogenation catalyst. A product stream including ethylene glycol may be obtained from the reactor
Implementation Method 3
The feed solution may include the carbohydrate feed, a soluble retro-Aldol catalyst, and an acid. The feed solution may include a glucose feed and a fructose feed, wherein the fructose content is less than 1% of the glucose content
Data Source
Figure 1
AI summary
Methods for producing ethylene glycol from a carbohydrate feed which may include preparing a feed solution including the carbohydrate feed, a soluble retro-Aldol catalyst, and an acid. The feed solution may be contacted, in a reactor under hydrogenation conditions, with a heterogeneous hydrogenation catalyst. A product stream including ethylene glycol may be obtained from the reactor.