ODH Reactor Outlet Pipe Fouling Prevention

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Solution Overview

Problem

Fouling in the outlet lines of oxidative dehydrogenation (ODH) reactors, particularly due to water-soluble by-products like maleic acid, leads to efficiency losses and potential blockages, which are not effectively addressed by existing methods suitable for larger oil and gas pipelines.

Innovation Solution

Introducing a solvent, preferably water, into the outlet pipe in a manner that promotes annular, laminar, or turbulent flow to dissolve and carry away fouling before it solidifies, using methods such as pipe-in-pipe arrangements, instream atomizers, or multiple holes on the inner surface of the pipe.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If downstream separation cooling is applied to condense reaction products, then separation efficiency is improved, but fouling occurs when water-soluble components condense and freeze adhering to reactor infrastructure

Engineering Contradiction:
Improveseparation efficiencyVSAvoidfouling
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces solvent into the outlet pipe upstream of where fouling is likely to develop, performing the cleaning action before the harmful condensation and freezing occurs during downstream separation cooling

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses solvent as an intermediary substance that dissolves water-soluble fouling components, preventing them from adhering to and freezing on the inner surface of the outlet pipe during the separation process

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If periodical shutdowns are implemented for cleaning pipelines, then fouling removal is achieved, but productivity and operational continuity deteriorate

Engineering Contradiction:
Improvefouling removalVSAvoidoperational continuity
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent enables continuous operation by introducing solvent during normal operation to prevent and remove fouling, eliminating the need for periodical shutdowns and maintaining continuous productivity

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system performs self-maintenance by continuously introducing solvent that prevents fouling accumulation, allowing the reactor to clean itself without external intervention or shutdown

Inventive Principle:
Principle #25Self-service

3Object-affected harmful factors

If water is used as cleaning fluid in pipelines, then fouling removal effectiveness is improved, but hydrate plug formation and moisture damage occur

Engineering Contradiction:
Improvefouling removal effectivenessVSAvoidhydrate plug formation
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent applies water specifically in the outlet pipe where fouling occurs, rather than throughout the entire pipeline system, and controls it to dissolve fouling without allowing conditions for hydrate formation

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the physical state and behavior of water by introducing it as liquid solvent under controlled conditions in the outlet pipe, where it dissolves fouling without forming hydrate plugs that would occur under different conditions in larger pipelines

Inventive Principle:
Principle #35Parameter changes

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

Prevents or removes fouling while the reactor is operational, reducing the need for costly shutdowns and maintaining efficiency by dissolving water-soluble by-products before they can adhere and solidify, thus avoiding flow blockages.

Implementation Method 1

dissolve and carry away fouling before it solidifies

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 2

promotes annular flow, laminar or turbulent, or slug flow, of solvent along the inner surface of the pipe

Methodology Applied
Scientific EffectAnnular flow:

Implementation Method 3

promotes annular flow, laminar or turbulent, or slug flow, of solvent along the inner surface of the pipe

Methodology Applied
Scientific EffectLaminar flow: Laminar Flow

Implementation Method 4

promotes annular flow, laminar or turbulent, or slug flow, of solvent along the inner surface of the pipe

Methodology Applied
Scientific EffectTurbulent flow: Turbulence

Implementation Method 5

when water soluble components, like maleic acid, condense and then freeze

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 6

when water soluble components, like maleic acid, condense and then freeze

Methodology Applied
Scientific EffectFreezing: Freezing

Data Source

PatentEP3723917B1Method for removing fouling downstream of an ODH reactor
Publication Date: 2023.06.07 NOVA CHEM (INT) SA
  • EP3723917B1 patent drawingFigure 1
  • EP3723917B1 patent drawingFigure 2~3
  • EP3723917B1 patent drawingFigure 4A~4B

AI summary

A method for preventing or removing water soluble fouling (7) located downstream of an oxidative dehydrogenation (ODH) reactor (3) is described. The method employs the introduction of water upstream of fouling locations, either continuously or intermittently, which acts to solubilize and carry away fouling material. The method has the advantage of being applicable for use while an ODH process is ongoing, circumventing the need for a costly shutdown.