Ammonia Purification Adsorbent Bed for Hydrocarbon Removal

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Solution Overview

Problem

Conventional two-column sour water stripping processes for ammonia purification often result in anhydrous liquid ammonia that does not meet Haber quality standards, necessitating costly blending with Haber quality ammonia to achieve market-grade product.

Innovation Solution

Incorporating an adsorbent bed using materials like silica and molecular sieves into the ammonia purification and liquefaction stage to enhance the removal of hydrocarbons from ammonia streams, allowing for the production of ammonia that meets Haber quality standards without additional blending costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional two-column sour water stripping process is used, then ammonia can be recovered from sour water, but the anhydrous liquid ammonia does not meet Haber quality standards due to hydrocarbon contamination

Engineering Contradiction:
Improveammonia purityVSAvoidhydrocarbon contamination
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent employs an adsorbent bed containing porous materials such as silica gel, molecular sieves, or activated alumina to remove hydrocarbon contaminants from the ammonia vapor stream. These porous materials provide large surface area for adsorption, enabling effective removal of trace hydrocarbons to achieve Haber quality standards (less than 1 ppm hydrocarbon content).

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The invention extracts the hydrocarbon contamination removal function from the conventional two-column stripping process by adding a separate adsorbent bed unit. This dedicated extraction step isolates and removes the harmful hydrocarbon components that the conventional process fails to eliminate, thereby producing high-purity Haber quality ammonia.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If conventional stripping process is used, then ammonia recovery is achieved, but costly blending with Haber quality ammonia is required to meet market standards

Engineering Contradiction:
Improveproduction costVSAvoidammonia quality standard
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The adsorbent bed enables the ammonia purification process to be self-sufficient by internally removing hydrocarbon contaminants to achieve Haber quality standards. This eliminates the need for external blending operations with expensive Haber quality ammonia, allowing the process to produce market-grade product independently and reduce overall manufacturing costs.

Inventive Principle:
Principle #25Self-service

3Object-generated harmful factors

If water wash and caustic wash are used to remove H2S and contaminants, then ammonia vapor is purified, but hydrocarbon removal remains insufficient

Engineering Contradiction:
Improveacid gas removalVSAvoidhydrocarbon removal efficiency
Core Design Contradiction:
Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The adsorbent bed acts as an intermediary step between the caustic wash and the ammonia liquefaction process. While water wash and caustic wash effectively remove acid gases (H2S, CO2), the adsorbent bed serves as a intermediate purification stage that specifically targets and removes hydrocarbon contaminants that the wash processes cannot eliminate, thereby achieving comprehensive purification.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 use of adsorbent beds improves the quality of anhydrous liquid ammonia to Haber quality, enabling it to be sold at the same price as Haber quality ammonia, thus addressing the long-standing issue of producing cost-effective, market-grade ammonia.

Implementation Method 1

each adsorbent bed including an adsorbent selected from the group consisting of silica and molecular sieves

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP3114084B1Systems and methods for ammonia purification
Publication Date: 2019.12.18 BECHTEL HYDROCARBON TECHNOLOGY SOLUTIONS INC
  • EP3114084B1 patent drawingFigure 1A
  • EP3114084B1 patent drawingFigure 1B
  • EP3114084B1 patent drawingFigure 2

AI summary

Systems and methods for ammonia purification in the NH3 purification and liquefaction stage of a conventional two-column sour water stripping system using an adsorbent bed.