Corrosion-Resistant Mixing Tee Assembly to Prevent Acid Trapping

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Solution Overview

Problem

Conventional mixing tee assemblies used in the production of phosphoric acid by attacking phosphate rocks with sulfuric acid are prone to corrosion and have a short lifespan due to turbulent flow and inadequate corrosion resistance, leading to residual sulfuric acid trapped in the pipes, which causes damage and requires frequent replacement.

Innovation Solution

A mixing tee assembly with an inner pipe lined with corrosion-resistant materials like PTFE and made of alloys such as Hastelloy C-276, extending the nozzle beyond the outer pipe to prevent acid trapping, combined with a rubber coating for additional protection, ensuring a tight fit and minimizing acid contact with the inner pipe.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If concentrated sulfuric acid is diluted and introduced into the reactor, then the acid is easier to handle, but large amount of heat is generated making the mixing tee assembly more vulnerable to corrosion

Engineering Contradiction:

Improveease of handling acidVSAvoidcorrosion vulnerability

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent employs a nested structure with an inner pipe containing a nozzle surrounded by an outer pipe. The inner pipe is positioned such that its nozzle extends beyond the mixing end of the outer pipe, creating a protected mixing zone where dilution occurs outside the vulnerable pipe sections.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent introduces a回流 acid stream as an intermediary substance that mixes with the concentrated sulfuric acid in the reaction tank rather than diluting it within the mixing tee assembly. This mediator allows the concentrated acid to be handled in the tee without direct contact with large volumes of water, reducing heat generation within the assembly.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If conventional mixing tee assemblies are used, then the structure is simple, but residual sulfuric acid is trapped in the pipes causing damage and requiring frequent replacement

Engineering Contradiction:

Improvestructural simplicityVSAvoidassembly lifespan

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The inner pipe with nozzle is nested within the outer pipe, creating a configuration where the nozzle extends beyond the outer pipe's mixing end. This nested design prevents acid trapping by ensuring complete discharge while maintaining relative structural simplicity.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

Instead of having the mixing end flush with or recessed from the outer pipe, the nozzle is extended beyond the outer pipe's mixing end. This inverted arrangement ensures that acid flows completely through the system without being trapped in dead zones, thereby extending assembly lifespan.

Inventive Principle:

Principle #13The other way round (Inversion)

3Volume of moving object

If the nozzle is positioned inside the outer pipe, then the structure is compact, but sulfuric acid is trapped in the mixing end causing corrosion

Engineering Contradiction:

Improveassembly compactnessVSAvoidacid trapping and corrosion

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The inner pipe is nested within the outer pipe with the nozzle extending beyond the outer pipe's mixing end. This nested configuration achieves compactness while preventing acid trapping by ensuring the nozzle discharge point is positioned outside the outer pipe's mixing zone.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The solution moves the critical mixing function from within the outer pipe to just outside it, utilizing the space beyond the outer pipe's mixing end. This dimensional repositioning prevents acid trapping while maintaining overall assembly compactness.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 novel design significantly extends the life expectancy of the mixing tee assembly by preventing corrosion and acid trapping, ensuring efficient acid mixing and reducing maintenance costs through improved corrosion resistance and efficient heat dispersal.

Implementation Method 1

the inner pipe is lined with a corrosion-resistant material on its inside surface

Methodology Applied

Scientific EffectCorrosion resistance:

Implementation Method 2

the turbulent flow inherent with the nozzle spray

Methodology Applied

Scientific EffectTurbulent flow: Turbulence

Implementation Method 3

combined with a rubber coating for additional protection

Methodology Applied

Scientific EffectPhysical barrier protection: Coatings

Data Source

PatentUS11229888B2Mixing tee assembly and process

Publication Date: 2022.01.25 FLOWORKS INTERNATIONAL LLC

AI summary

A mixing tee assembly suitable for phosphate acid attack reaction is described. The mixing tee assembly comprises an outer pipe having a mixing end and a tee end, wherein a tee structure is formed near the tee end to connect with additional piping; an inner pipe comprising a nozzle end connected to a nozzle and a open end; wherein the inner pipe is lined with a corrosion-resistant material on its inside surface; wherein when the inner pipe is assembled within the outer pipe, the nozzle extends beyond the mixing end of the outer pipe by at least ⅓ of the inside diameter of the outer pipe.