Divided Wall Distillation Column for 1,4-Dioxane Removal
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Solution Overview
Problem
Current methods for treating 1,4-dioxane in discharged water from ethylene oxide and ethylene glycol production are inefficient, requiring high ozone or chemical doses, increasing costs, and often necessitate additional facilities and heating sources, with existing bacteria not being effectively applied in treatment processes.
Innovation Solution
A method utilizing a divided wall distillation column for concentrating and separating 1,4-dioxane during the ethylene glycol concentration process, allowing for its efficient removal from discharged water, thereby reducing concentrations to environmentally acceptable levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If activated sludge method or activated carbon adsorption method is used to treat 1,4-dioxane in discharged water, then treatment process is simple, but 1,4-dioxane cannot be sufficiently removed
Solution Approach 1:
The patent changes the fundamental treatment parameter from biological/adsorption methods to distillation-based separation. By utilizing the volatility difference between 1,4-dioxane and water, the system achieves effective removal through phase change and separation, fundamentally altering the treatment mechanism to overcome the limitations of biological degradation methods.
Solution Approach 2:
The patent replaces the biological treatment system (activated sludge) or adsorption system (activated carbon) with a mechanical separation system (distillation column). This substitution uses physical phase change and mass transfer principles to separate 1,4-dioxane from water, achieving reliable removal without depending on biological activity or adsorption capacity.
2Reliability
If ozone treatment or accelerated oxidation treatment is used to remove 1,4-dioxane, then 1,4-dioxane removal efficiency is improved, but organic matters are also decomposed requiring increased chemical feeding amount and processing cost
Solution Approach 1:
The patent extracts 1,4-dioxane from the discharged water through distillation separation, isolating it from other organic matters. This selective extraction allows for targeted removal of 1,4-dioxane without affecting other organic compounds, eliminating the need for large amounts of oxidizing chemicals that would decompose all organic matter indiscriminately.
Solution Approach 2:
The patent converts the harmful property of 1,4-dioxane (its presence in discharged water) into a beneficial separation opportunity. By exploiting the volatility and steam pressure characteristics of 1,4-dioxane, the system transforms the treatment challenge into a separation advantage, where the substance's own properties facilitate its removal without requiring aggressive chemical treatment.
3Reliability
If distillation method is used to separate 1,4-dioxane from discharged water, then separation efficiency is improved, but additional facilities and heating sources are required increasing construction cost and installation area
Solution Approach 1:
The patent integrates the 1,4-dioxane separation function into the existing ethylene glycol concentration process. The same distillation column used for concentrating ethylene glycol also performs 1,4-dioxane separation, allowing one facility to serve multiple functions. This multi-functionality eliminates the need for separate dedicated 1,4-dioxane treatment facilities, reducing construction cost and installation area.
Solution Approach 2:
The patent merges two separate processes (ethylene glycol concentration and 1,4-dioxane separation) into a single integrated operation. By combining these functions in one distillation system, the patent reduces the total number of facilities required and utilizes shared infrastructure, thereby lowering capital investment and operational complexity.
4Reliability
If multiple separate treatment steps are used for ethylene glycol concentration and 1,4-dioxane removal, then treatment thoroughness is improved, but process complexity and operational cost increase
Solution Approach 1:
The patent combines ethylene glycol concentration and 1,4-dioxane separation into a single integrated distillation process. The distillation column simultaneously achieves both objectives by exploiting differences in volatility and steam pressure, reducing multiple sequential steps into one unified operation that maintains treatment thoroughness while simplifying the overall process flow.
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 use of a divided wall distillation column effectively reduces 1,4-dioxane concentrations in discharged water to 0.5 mg/L or less, improving treatment efficiency and reducing operational costs compared to traditional methods.
Implementation Method 1
a method utilizing a divided wall distillation column for concentrating and separating 1,4-dioxane during the ethylene glycol concentration process
Implementation Method 2
concentrating ethylene glycol produced as a by-product
Implementation Method 3
concentrating ethylene glycol produced as a by-product
Data Source
Figure 1
Figure 2
Figure 3(a)~3(c)
AI summary
There is provided a method of producing ethylene oxide and ethylene glycol capable of reducing a concentration in discharged water of 1,4-dioxane contained generated in a step of producing ethylene oxide and ethylene glycol. A method of producing ethylene oxide and ethylene glycol includes a predetermined step of producing ethylene oxide, and a step of extracting a part of a column bottom liquid of an ethylene oxide stripping column in the step of producing ethylene oxide and supplying the extracted column bottom liquid to a by-produced ethylene glycol concentration column, concentrating ethylene glycol produced as a by-product in the step of producing ethylene oxide, and distilling and separating 1,4-dioxane produced as a by-product in the step of producing ethylene oxide, wherein the by-produced ethylene glycol concentration column is a divided wall distillation column.