Two-Tank Ammonia Absorption for Inert-Gas Purging

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Solution Overview

Problem

Existing ammonia abatement systems struggle with inefficient absorption of inert gases like nitrogen during purging, leading to reduced ammonia absorption capacity and potential flooding due to high flow rates, which results in inert gases being released into the environment.

Innovation Solution

An ammonia abatement system with a first and second tank, each containing absorption liquid, and a pressure regulating valve to manage gas transfer between tanks, ensuring efficient absorption of ammonia and inert gases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a closed space such as a scrubber or cooling tower is used to absorb ammonia, then ammonia absorption is achieved, but the high flow rate of inert gas reduces absorption capacity and may cause flooding

Engineering Contradiction:
Improveammonia absorption capacityVSAvoidabsorption efficiency
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The system divides the absorption process into two independent stages: a first absorption device for initial ammonia absorption, and a second absorption device for residual ammonia absorption. This segmentation allows each device to be optimized for its specific function, preventing the high inert gas flow rate from overwhelming a single absorption system and causing flooding while maintaining overall absorption capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inert gas acts as an intermediary carrier that transports ammonia from the fuel system to the absorption devices. The system leverages this intermediary role by designing the absorption process to handle the inert gas flow systematically through multiple stages, using the inert gas itself as the transport medium rather than resisting it.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If inert gas is used for purging the fuel system, then ammonia is discharged from the pipe, but the inert gas is difficult to be absorbed in water and is released into the environment

Engineering Contradiction:
Improvepurging capabilityVSAvoidinert gas emission
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The system converts the previously harmful inert gas emission into a beneficial transport mechanism. The inert gas, instead of being released directly into the environment, is utilized as a carrier gas to deliver ammonia to the absorption devices where it can be captured and converted into useful liquid ammonia or ammonium compounds.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system maintains an inert atmosphere throughout the absorption process, using the inert gas to create a controlled environment that prevents unwanted reactions while facilitating the transfer and absorption of ammonia. The inert atmosphere is managed systematically through the two-stage absorption process rather than being discharged.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Speed

If the flow rate of inert gas is high during purging, then purging is effective, but the absorption capacity for ammonia is reduced and flooding may occur

Engineering Contradiction:
Improvepurging speedVSAvoidammonia absorption capacity
Core Design Contradiction:
SpeedVSQuantity of substance

Solution Approach 1:

The absorption system is segmented into two separate devices, allowing the high flow rate inert gas to be handled in stages. The first absorption device processes the initial high-flow inert gas stream, while the second device handles residual ammonia, preventing flooding in any single device while maintaining overall absorption capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adapts to varying inert gas flow rates during the purging process. The two-stage absorption configuration allows the system to maintain effectiveness across a range of flow conditions, with each stage designed to handle different portions of the gas stream appropriately.

Inventive Principle:
Principle #15Dynamics

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 system maintains ammonia absorption capacity during purging by effectively handling inert gases, preventing flooding, and ensuring safe disposal of purge gases.

Implementation Method 1

an absorption liquid that is capable of absorbing ammonia; promotes the absorption of ammonia to be performed by the absorption liquid in the first tank

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP4592174A1Ammonia detoxification system, floating body, and ammonia detoxification method
Publication Date: 2025.07.30 MITSUBISHI HEAVY IND LTD
  • EP4592174A1 patent drawingFigure 1
  • EP4592174A1 patent drawingFigure 2
  • EP4592174A1 patent drawingFigure 3

AI summary

An ammonia abatement system includes a first tank that stores an absorption liquid capable of absorbing ammonia, a first introduction line that can introduce purge gas containing ammonia and inert gas into the first tank, a first absorption promoting unit that promotes absorption of ammonia to be performed by the absorption liquid in the first tank, a first liquid discharge line that can discharge liquid from a liquid phase in the first tank, a first gas discharge line that can discharge gas from a gas phase in the first tank, a second tank that is provided independently of the first tank, an upper connection line that connects the gas phase in an upper portion of the first tank and an upper portion of the second tank, and a pressure regulating valve that is provided in the connection line and can be opened and closed according to a pressure of the gas phase in the first tank.