Dioxolane Process Phase Separation Methanol Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing processes for preparing dioxolane result in high losses of the valuable product and require significant amounts of auxiliary substances that need to be purified or discharged, leading to inefficiencies and waste.
Innovation Solution
A process involving a reaction distillation device where ethylene glycol and formaldehyde are reacted in the presence of a catalyst, with a phase separation unit and organic extracting agent to enhance separation, recycle the extracting agent, and withdraw a side stream containing methanol to prevent accumulation, thereby increasing dioxolane yield and purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If benzene is used as an extracting agent to break the azeotrope in dewatering column, then water removal efficiency is improved, but the process requires additional purification steps and generates waste that must be discharged
Solution Approach 1:
The invention extracts and removes benzene from the process by introducing a side stream withdrawal unit that specifically removes benzene from the distillation column output. This extracted benzene is then recycled back to the dewatering column, eliminating waste discharge while maintaining the azeotrope-breaking function.
Solution Approach 2:
Instead of discharging benzene-containing waste, the invention recovers benzene through the side stream withdrawal unit and recycling system. The benzene is discarded from the waste stream and recovered for reuse, transforming a waste disposal problem into a resource recovery solution.
2Manufacturing precision
If multiple distillation columns are used to purify dioxolane, then product purity is improved, but part of the valuable dioxolane product is lost due to necessary discharge from the top of the purification column
Solution Approach 1:
The invention implements a feedback mechanism where the distillate from the purification column, which contains dioxolane, is not discharged but instead recycled back to the dewatering column. This closed-loop feedback system maintains product purity while preventing valuable dioxolane loss.
Solution Approach 2:
The invention ensures continuous useful action by recycling the dioxolane-containing distillate back into the process rather than discontinuing it through discharge. This continuous circulation maintains both purity requirements and minimizes product loss.
3Reliability
If a side stream containing methanol is withdrawn from the waste water column, then methanol accumulation is prevented, but an additional process step is required
Solution Approach 1:
The invention applies preliminary action by proactively withdrawing methanol through the side stream before it can accumulate to problematic levels. This preventive measure ensures stable operation by maintaining methanol concentrations within safe operating parameters throughout the process.
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 high purity of dioxolane with minimal product loss and complete recycling of the extracting agent, ensuring stable and efficient operation by efficiently separating components and removing side products like methanol.
Implementation Method 1
transferring a distillate stream containing raw product from the top of the reaction distillation device to a phase separation unit, wherein an organic extracting agent is present in the phase separation unit
Implementation Method 2
transferring an organic fraction stream from the phase separation unit to an upper part of a purification column, withdrawing a bottom product stream containing dioxolane from the purification column
Implementation Method 3
reacting ethylene glycol and formaldehyde in aqueous solution in the presence of at least one catalyst to obtain a raw product which comprises water, dioxolane and methanol
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a process for preparing dioxolane by reacting ethylene glycol with an aqueous solution of formaldehyde in the presence of an acid catalyst. The raw product comprising water, dioxolane and methanol is fed to a phase separation unit (20) wherein an organic extracting agent is present. An organic fraction stream from the phase separation unit is transferred to an upper part of a purification column (30) from which dioxolane is withdrawn as a bottom product while the distillate stream of the purification column is recycled to the phase separation unit. An aqueous fraction stream from the phase separation unit is transferred to a waste water column (40), withdrawing a waste water stream from the bottom of the waste water column, recycling a distillate stream (42) from the waste water column to the phase separation unit, and withdrawing a side stream (43) containing methanol from a stage below the feed stage of the waste water column.