Titanium Alloy Reactor for Polycarbonate Corrosion Resistance

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Solution Overview

Problem

Existing reactors for manufacturing interfacial polycarbonate using phosgene as the carbonate source are prone to corrosion from chlorine-containing materials, leading to complexity, fragility, and sensitivity to mechanical and thermal loads, as well as basic conditions.

Innovation Solution

A reactor with a titanium alloy comprising palladium, such as ASTM Ti-grade 7, 33, or 34, is used for the reactor vessel and internals, providing enhanced resistance to mechanical and thermal loads, as well as chemical resistance to both acidic and basic conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If glass-lined reactors are used to resist corrosion from hydrochloric acid, then chemical resistance to acidic conditions is improved, but mechanical strength and resistance to thermal shocks are worsened

Engineering Contradiction:
Improvechemical resistanceVSAvoidmechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent employs a glass-lined reactor where a glass coating (providing chemical resistance) is applied over a metal substrate (providing mechanical strength). This composite structure combines the advantages of both materials: the glass layer resists corrosion from hydrochloric acid while the metal base provides the necessary mechanical integrity and thermal shock resistance.

Inventive Principle:
Principle #40Composite materials

2Reliability

If glass-lined reactors are used to resist corrosion, then chemical resistance is improved, but device complexity and susceptibility to mechanical damage are worsened

Engineering Contradiction:
Improvechemical resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The glass-lined reactor represents a composite material solution where the glass coating is applied to a metal substrate. This approach provides chemical resistance while maintaining relatively simple manufacturing processes compared to other corrosion-resistant materials, and the metal base simplifies handling and installation.

Inventive Principle:
Principle #40Composite materials

3Reliability

If glass-lined reactors are used to resist hydrochloric acid corrosion, then chemical resistance to acidic conditions is improved, but resistance to basic conditions is worsened

Engineering Contradiction:
Improvechemical resistanceVSAvoidsensitivity to basic conditions
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The glass lining acts as an intermediary protective barrier between the reactor contents and the metal substrate. While glass provides excellent resistance to hydrochloric acid, the patent acknowledges its sensitivity to basic conditions and manages this through process control and selection of appropriate glass compositions that balance resistance to both acidic and basic environments.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4347688B1Reactor and method for the manufacture of polycarbonate
Publication Date: 2025.02.19 SABIC GLOBAL TECHNOLOGIES BV
  • EP4347688B1 patent drawingFigure 1

AI summary

Disclosed herein is a reactor for the manufacture of interfacial polycarbonate by reacting phosgene and one or more bisphenols in a liquid phase, the reactor comprising a reactor vessel and reactor internals, wherein at least part of the inner surface of the reactor and/or part of the surface of the reactor internals is manufactured from or cladded with a titanium alloy comprising palladium.