Loop Reactor Heat Exchanger Turbulators for Acetone Cyanohydrin Hydrolysis

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Solution Overview

Problem

The hydrolysis of acetone cyanohydrin with sulfuric acid in the ACH-sulfo process for producing methacrylic acid or methyl methacrylate faces issues with yield reduction due to side reactions and inefficient heat dissipation, leading to temperature peaks and pressure losses in loop reactors, which are exacerbated by the increased viscosity and laminar flow as temperature drops.

Innovation Solution

Equipping heat exchangers in loop reactors with turbulators and using a metering ring for precise feeding of reactants, integrated with pumps, to enhance heat exchange efficiency and mixing while minimizing pressure loss, with turbulators installed in heat exchangers and metering rings positioned to promote turbulent flow and optimal mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the mixture is cooled too much before dosing ACH to remove reaction heat, then heat dissipation is improved, but viscosity increases sharply and flow turbulence decreases into laminar range leading to inefficient heat dissipation and slower mixing

Engineering Contradiction:
Improvereaction mixture temperatureVSAvoidmixing efficiency and heat dissipation efficiency
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The system dynamically adjusts the balance between cooling intensity and flow turbulence by integrating the heat exchanger within the loop reactor circulation system. The continuous circulation and controlled cooling maintain optimal temperature while preserving turbulent flow conditions through the dynamic interaction of cooling rate and flow velocity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The heat exchanger is merged with the loop reactor system, where the reaction mixture circulates through the heat exchanger and returns to the reactor. This integration allows simultaneous heat removal and maintenance of turbulent flow, as the circulation pump maintains flow velocity while the heat exchanger provides controlled cooling.

Inventive Principle:
Principle #5Merging (Combining)

2Stability of the object's composition

If mixing units are added to the loop reactor to improve mixing, then mixing efficiency is improved, but flow resistance increases significantly leading to pressure losses and reduced flow rate

Engineering Contradiction:
Improvemixing homogeneityVSAvoidpressure loss
Core Design Contradiction:
Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The loop reactor system uses its own circulation flow and the natural turbulence generated by the pump and heat exchanger to achieve mixing, eliminating the need for separate mixing units. The continuous circulation and temperature-driven convection currents provide sufficient mixing action without adding external mixing equipment that would increase pressure loss.

Inventive Principle:
Principle #25Self-service

3Productivity

If residence time is increased to improve reaction conversion, then conversion is improved, but temperature peaks increase leading to yield reduction due to the temperature-sensitive nature of the reaction

Engineering Contradiction:
Improvereaction conversionVSAvoidtemperature peak
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The loop reactor provides continuous circulation and continuous heat removal, maintaining steady-state temperature conditions throughout the reaction. This continuous action allows extended residence time for high conversion while preventing temperature peaks through constant heat dissipation, as the system operates in a stable, continuous manner rather than batch-wise.

Inventive Principle:
Principle #20Continuity of useful action

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 improves heat exchange efficiency, reduces pressure losses, and increases yield by maintaining turbulent flow and efficient mixing, resulting in higher production yields and better temperature control during the hydrolysis process.

Implementation Method 1

The reaction is exothermic, so that heat of reaction is advantageously removed from the system

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

they have the advantage of primarily enabling good heat exchange because they reduce the tendency to form a laminar flow

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 3

Rapid mixing of ACH and reaction mixture is required because the ACH should react before it decomposes due to heating

Methodology Applied
Scientific EffectTurbulent flow mixing: Turbulence

Implementation Method 4

acetone cyanohydrin is subjected to hydrolysis. The desired MAAm is formed after a series of reactions at different temperature levels

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 5

The reaction is exothermic, so that heat of reaction is advantageously removed from the system

Methodology Applied
Scientific EffectExothermic reaction: Exothermic Reaction

Data Source

PatentEP2830753B1Method for hydrolysing acetone cyanohydrin
Publication Date: 2020.08.26 ROHM GMBH
  • EP2830753B1 patent drawingFigure 1
  • EP2830753B1 patent drawingFigure 2
  • EP2830753B1 patent drawingFigure 3

AI summary

The present invention relates to a method for hydrolysing acetone cyanohydrin (ACH) by sulphuric acid in the context of the ACH-sulpho method for producing methacrylic acid (MAA) or methyl methacrylate (MMA).