Alkylene Glycol Process Using Ejector Mixing in Single Reactor

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Solution Overview

Problem

Current processes for producing alkylene glycol from alkylene oxide are complex and costly, requiring multiple reactors and steps, which increases capital expenditure and operational complexity.

Innovation Solution

A process involving a single reactor vessel divided into compartments by internal baffles, where alkylene oxide reacts with carbon dioxide and water in the presence of homogeneous catalysts, using ejectors for mixing, and recycling reagents to promote efficient carboxylation and hydrolysis reactions, achieving high conversion of alkylene oxide to alkylene glycol.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple reactors and steps are used for producing alkylene glycol from alkylene oxide, then the conversion efficiency and product quality are improved, but the device complexity and capital expenditure increase

Engineering Contradiction:
Improveconversion efficiencyVSAvoidnumber of reactors and steps
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines the carboxylation reaction zone and hydrolysis reaction zone into a single integrated reactor vessel, eliminating the need for multiple separate reactors. The reactor contains both zones with appropriate catalysts and conditions to perform both reactions sequentially or simultaneously, thereby reducing device complexity and capital expenditure while maintaining high conversion efficiency

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single reactor vessel is divided into distinct carboxylation and hydrolysis zones using internal baffles or spatial separation. This segmentation allows each zone to operate with optimized conditions (catalysts, temperature, pressure) for its specific reaction while remaining part of a unified system, achieving both reaction efficiency and structural simplicity

Inventive Principle:
Principle #1Segmentation

2Productivity

If multiple reactors and steps are used for producing alkylene glycol from alkylene oxide, then the conversion efficiency is improved, but the operational complexity increases

Engineering Contradiction:
Improveconversion efficiencyVSAvoidoperational complexity
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

By integrating both carboxylation and hydrolysis reactions in one reactor, the patent reduces the number of operational steps, transfers, and process control points. The unified system requires fewer operational interventions and simplifies process monitoring while achieving high conversion through optimized zonal conditions

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If a single reactor with compartments is used, then the device complexity and capital costs are reduced, but the mixing efficiency and reaction performance may worsen

Engineering Contradiction:
Improvereactor structureVSAvoidreaction performance
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent employs ejectors as mixing devices that utilize fluid dynamics to achieve efficient mixing of reactants and catalysts within each reaction zone. The ejectors create intense turbulence and mass transfer without requiring complex mechanical agitators, thereby maintaining high reaction performance while keeping the reactor structure simple

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Each reaction zone (carboxylation and hydrolysis) is equipped with localized mixing elements (ejectors) and catalysts optimized for its specific reaction requirements. This local optimization ensures high reaction performance in each zone while the overall reactor remains structurally simple and cost-effective

Inventive Principle:
Principle #3Local 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 process achieves high conversion of alkylene oxide to alkylene glycol (>99%) in a simpler and more economical setup, reducing capital costs and operational complexity.

Implementation Method 1

using one or more ejectors to mix carbon dioxide and the liquid reagents in the carboxylation zone

Methodology Applied
Scientific EffectMixing:

Implementation Method 2

alkylene oxide reacts with carbon dioxide in the presence of water to form a reaction solution comprising alkylene carbonate

Methodology Applied
Scientific EffectCarboxylation reaction:

Implementation Method 3

alkylene carbonate and water react to form a product solution comprising alkylene glycol

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 4

Heat from the exothermic carboxylation reaction is removed by cooling the extracted reaction mixture in a heat exchanger

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP2222622B1Process for the preparation of alkylene glycol
Publication Date: 2014.04.30 SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV
  • EP2222622B1 patent drawingFigure 1
  • EP2222622B1 patent drawingFigure 2
  • EP2222622B1 patent drawingFigure 3

AI summary

The invention provides a process and a reactor for the preparation of an alkylene glycol from an alkylene oxide. Alkylene oxide, water, a homogeneous carboxylation catalyst and a homogenous hydrolysis catalyst are supplied to a reactor comprising a carboxylation zone and a hydrolysis zone. One or more ejectors are used to mix carbon dioxide and the liquid reagents in the carboxylation zone so that alkylene oxide reacts with carbon dioxide in the presence of water in the carboxylation zone to form a reaction solution comprising alkylene carbonate, water, the homogeneous carboxylation catalyst and the homogeneous hydrolysis catalyst. The reaction solution is supplied from the carboxylation zone to a hydrolysis zone, wherein alkylene carbonate and water react to form a product solution comprising alkylene glycol, the homogeneous carboxylation catalyst and the homogeneous hydrolysis catalyst. Carbon dioxide released by the reaction of alkylene carbonate and water in the hydrolysis zone is supplied to the carboxylation zone. Product solution is withdrawn from the hydrolysis zone.