Bio-Succinic Acid Esterification with Counter-Current Purification
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Solution Overview
Problem
Conventional processes for producing 1,4-butanediol from succinic acid, especially when derived from fermentation, face challenges due to impurities, catalyst deactivation, and high costs associated with purification and recycling, particularly when using copper-based catalysts or acid resin catalysts.
Innovation Solution
A process involving an autocatalytic reaction in a stirred tank reactor followed by counter-current esterification in a reaction zone column, allowing for the production of dialkyl succinate without the need for extensive purification, using bio-succinic acid directly and recycling unreacted acid and mono-ester to enhance conversion and reduce impurity effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional purification steps are used to remove impurities from bio-succinic acid, then catalyst deactivation is reduced, but capital and operating costs increase significantly
Solution Approach 1:
The harmful impurities (especially sulfur compounds) are extracted and removed from the bio-succinic acid stream through a dedicated purification train including extraction columns and adsorption beds, separating the impurities from the main feedstock before it reaches the catalyst
Solution Approach 2:
An intermediary purification system is introduced between the bio-succinic acid feed and the catalytic reactor. This includes extraction solvents and adsorbent materials that act as mediators to remove impurities without requiring direct contact between the impurities and the catalyst
2Reliability
If extensive purification steps are implemented, then catalyst deactivation is prevented, but operating costs and process complexity increase
Solution Approach 1:
Purification actions are taken in advance before the feedstock enters the reactor. The purification train is positioned upstream to remove impurities proactively, preventing catalyst deactivation before it occurs rather than treating it afterward
Solution Approach 2:
The purification system uses relatively simple, replaceable components such as extraction solvents and adsorbent beds that can be regenerated or replaced economically, avoiding the need for complex, expensive permanent purification systems
3Ease of manufacture
If bio-succinic acid with impurities is used directly, then purification costs are reduced, but catalyst deactivation occurs
Solution Approach 1:
The purification process is designed to handle the impurity profile of bio-succinic acid specifically, converting the potential harm of impurities into a manageable separation problem. The extraction and adsorption steps are optimized for the specific impurities present in fermentation-derived succinic acid
4Manufacturing precision
If complex purification and recycling systems are used, then product purity is improved, but capital costs increase
Solution Approach 1:
The recycling system incorporates feedback control where the purity of the dialkyl succinate product is monitored and the purification process parameters are adjusted accordingly. Unreacted bio-succinic acid and intermediates are recycled back to the reactor with controlled purification to maintain product quality
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 reduces capital and operating costs by eliminating the need for complex purification steps, maintains catalyst activity, and achieves high conversion rates of succinic acid to dialkyl succinate, suitable for hydrogenation reactions, thus improving the economic viability and efficiency of the process.
Implementation Method 1
an autocatalytic reaction in a stirred tank reactor followed by counter-current esterification in a reaction zone column, allowing for the production of dialkyl succinate without the need for extensive purification
Implementation Method 2
counter-current esterification in a reaction zone column, allowing for the production of dialkyl succinate without the need for extensive purification
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A process for the production of dialkyl succinate from a bio-succinic acid feedstock comprising the steps of; (a) feeding solid bio-succinic acid to a first reactor where it is contacted with alkanol, said first reactor being operated at a suitable temperature and pressure to enable autocatalytic esterification to occur; (b) passing a stream removed from the first reactor comprising unreacted succinic acid, mono alkyl ester, dialkyl ester, alkanol, water and impurities to a point at or near the top of a reaction zone columm operated at temperatures and pressures to enable esterification of the succinic acid and further esterification of the mono alkyl ester, and passing said stream in counter-current reaction to upflowing additional alkanol; (c) removing a stream from at or near the bottom of the reaction zone column comprising components selected from residua! succinic acid, mono alkyl ester, dialkyl ester, impurities and alkanol and passing said stream to a bottoms stream separation zone where said di-alkyl ester is separated from alkanol, and from the succinic acid, mono alkyl ester and impurities; (d) recycling the succinic acid and mono alkyl ester to the reaction zone column; (e) removing at least some of the impurities as a purge; and (f) removing a stream comprising alkanol, water and organic components from at or near the top of the reaction zone column and passing said stream to a top stream distillation zone where the alkanol is separated, from the water and from the organic components and recycling the organic components to the reaction zone column.