Two-Stage Sorbent Purification for Halogen Removal

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Solution Overview

Problem

Existing processes for removing halogen compounds, particularly chlorine compounds, from process fluids in hydrocarbon and hydrogen-containing gases and liquids are inefficient, leading to corrosive damage and catalyst poisoning, and often require expensive Pt or Pd hydrogenation catalysts.

Innovation Solution

A two-stage process using a first sorbent to remove hydrogen halide from process fluids, followed by a second sorbent to remove organic halide compounds, without the need for expensive Group VIII catalysts, utilizing sorbents like alkalised zinc-alumina and transition alumina or zeolites to achieve improved halogen compound removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Pt or Pd hydrogenation catalysts are used to remove organic halide compounds, then removal effectiveness is improved, but cost increases significantly

Engineering Contradiction:
Improvehalogen compound removal effectivenessVSAvoidprocess cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The purification process is divided into two sequential stages: first removing hydrogen halide compounds using a hydrogen halide sorbent, then removing organic halide compounds using an organic halide sorbent. This segmentation allows each sorbent to be optimized for its specific function, avoiding the need for expensive Pt or Pd catalysts while achieving effective removal of both types of halogen compounds.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention replaces expensive Pt or Pd hydrogenation catalysts with cheaper sorbent materials that can be regenerated or replaced more economically. The sorbents used are significantly less costly than noble metal catalysts, making the overall process more economically viable despite potentially shorter service life.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Device complexity

If a single sorbent is used to remove both hydrogen halide and organic halide compounds, then device complexity is reduced, but removal effectiveness deteriorates due to sorbent saturation

Engineering Contradiction:
Improvenumber of sorbent stagesVSAvoidhalogen compound removal effectiveness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The process uses two distinct sorbent stages: a first sorbent specifically for hydrogen halide removal and a second sorbent for organic halide removal. This segmentation prevents cross-contamination and saturation issues that would occur with a single sorbent, as each sorbent is optimized for its target compound type.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first sorbent acts as an intermediary that removes hydrogen halide compounds before the process fluid reaches the second sorbent. This prevents the second sorbent from becoming saturated by hydrogen halide, ensuring it maintains its effectiveness for organic halide removal.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If hydrogen halide sorbent is placed before organic halide sorbent, then organic halide removal is improved by preventing sorbent saturation, but process complexity increases

Engineering Contradiction:
Improveorganic halide removal effectivenessVSAvoidsorbent arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The hydrogen halide sorbent is placed upstream to perform preliminary removal of hydrogen halide compounds before the process fluid reaches the organic halide sorbent. This preliminary action prevents saturation of the second sorbent, ensuring it remains effective for its primary function of organic halide removal throughout its service life.

Inventive Principle:
Principle #10Preliminary 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 process effectively reduces halogen compound levels to below 2 ppm, preventing equipment damage and catalyst poisoning, while avoiding the use of costly Pt or Pd catalysts, and is particularly effective for hydrogen-rich gas streams and liquid hydrocarbon streams.

Implementation Method 1

passing a process fluid containing hydrogen halide over a first sorbent to remove hydrogen halide

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

passing the hydrogen halide depleted process fluid over a second sorbent to remove organic halide compounds therefrom

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentUS10722833B2Purification process
Publication Date: 2020.07.28 JOHNSON MATTHEY DAVY TECHNOLOGIES LTD

AI summary

A process is described for removing halogen compounds, particularly chlorine compounds, from a process fluid, comprising the steps of (i) passing a process fluid containing hydrogen halide over a first sorbent to remove hydrogen halide and generate a hydrogen halide depleted process fluid and then, (ii) passing the hydrogen halide depleted process fluid over a second different sorbent to remove organic halide compounds therefrom. A purification system suitable for removing hydrogen halide and organic halide compounds from process fluids is also described.