Internal Loop Reactor Draft Tube Segmentation for Scale-Up

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Solution Overview

Problem

Conventional internal loop reactors are limited in size due to practical difficulties in bending large tubes and constructing large vessels under high pressure, which restricts the reactor volume to around 8-12 cubic meters.

Innovation Solution

Incorporating a heat exchanger formed by a plurality of cooling tubes as a draft tube between the riser and downcomer sections, allowing for easier construction and attachment of reactor parts, and providing lateral support to manage buckling stresses, enabling larger reactor volumes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of stationary object

If conventional internal loop reactor design is used, then construction is simpler, but reactor volume is limited to 8-12 cubic meters

Engineering Contradiction:
Improvereactor volumeVSAvoidconstruction difficulty
Core Design Contradiction:
Volume of stationary objectVSEase of manufacture

Solution Approach 1:

The draft tube is segmented into multiple cooling tubes connected by webs or metal strips, allowing the structure to be assembled in sections rather than as a single large piece. This segmentation enables easier construction and reduces the difficulty of bending large tubes while achieving the desired large reactor volume.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cooling tubes serve dual functions: they provide heat exchange surfaces for temperature control and simultaneously form the structural draft tube separating riser and downcomer sections. This multi-functionality eliminates the need for separate structural components, simplifying construction while enabling larger reactor volumes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If larger reactor vessels are constructed under high pressure, then reaction capacity increases, but construction difficulty increases due to buckling stresses

Engineering Contradiction:
Improvereaction capacityVSAvoidresistance to buckling stresses
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The webs or metal strips connecting the cooling tubes function as flexible structural elements that can accommodate buckling stresses while maintaining the draft tube configuration. These flexible connections allow the structure to withstand high pressure conditions without failing, enabling larger reactor vessels to be constructed.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The draft tube structure combines multiple materials (cooling tubes, webs, metal strips) to create a composite structure that leverages the strength properties of each component. This composite construction provides enhanced resistance to buckling stresses while maintaining the necessary heat exchange functionality for large-scale reactions.

Inventive Principle:
Principle #40Composite materials

3Strength

If cooling tubes are connected by webs or metal strips, then lateral support and buckling stress management improve, but device complexity increases

Engineering Contradiction:
Improvelateral support capabilityVSAvoidstructural complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The cooling tubes, webs, and metal strips are merged into a single integrated draft tube structure that performs both heat exchange and structural support functions. This merging eliminates the need for separate support structures, reducing overall device complexity while maintaining lateral support capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cooling tubes themselves serve as the primary structural element of the draft tube, utilizing their own rigidity and the connections between them to provide lateral support and resist buckling stresses. This self-service approach eliminates the need for additional support structures, simplifying the overall device design.

Inventive Principle:
Principle #25Self-service

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 design facilitates the construction and maintenance of larger internal loop reactors, increasing reactor volume significantly, allowing for a scale-up of reactions like the Oxo Process to volumes of 20-40 cubic meters with stable temperature control and efficient fluid circulation.

Implementation Method 1

the heat exchange means comprises a plurality of cooling tubes attached to each other by webs or metal strips attached between the tubes over a predetermined length

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

The difference between the specific gravities of the gas/liquid phase mixture on the one hand and the liquid phase alone on the other hand results in a difference in hydrostatic pressure between the ascending branch and the descending branch, thus leading to circulation of the liquid phase in the reactor

Methodology Applied
Scientific EffectGravity-driven phase separation: Gravitation

Implementation Method 3

The hydroformylation reaction, also known as the Oxo Reaction or Oxo Process, consists in reacting a synthesis gas made up of a mixture of carbon monoxide and hydrogen and at least one C n H 2n olefin so as to obtain a mixture of aldehydes and primary alcohols containing n+1 carbon atoms. The reaction is generally catalyzed with carbonyls of transition metals such as cobalt.

Methodology Applied
Scientific EffectCatalysis: Catalysis

Data Source

PatentEP2043774B1Olefin hydroformylation process in an internal loop reactor
Publication Date: 2011.06.15 EXXONMOBIL CHEMICAL PATENTS INC
  • EP2043774B1 patent drawingFigure 1~2A
  • EP2043774B1 patent drawingFigure 2B
  • EP2043774B1 patent drawingFigure 3

AI summary

The invention relates to improvements in internal loop reactors. The reactor of the invention is characterized by a plurality of cooling tubes which form the annulus between the riser and the downcomer path of said internal loop reactor. The reactor also provides improvements in hydroformylation reactions using the improved reactor.