Pressurized Air Injection for Aluminum Cell Effluent Collection

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Solution Overview

Problem

Existing systems for collecting and treating effluents from aluminum electrolysis cells face inefficiencies due to the release of effluents into the atmosphere when hoods or doors are opened for maintenance, leading to reduced collection efficiency and potential damage to mechanical components from high temperatures and corrosive substances.

Innovation Solution

A system that includes a pipe with a pressurized air supply to enhance gas flow rates in outlet channels, using adjustable pressure and flow rates to maintain efficient effluent collection without mechanical parts in the effluent flow, thereby increasing the gas flow rate by 1.5 to 3 times with pressurized air flow rates between 5 and 15% of normal gas flow and pressures below 5 bars.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If mechanical shutters or flaps are used to increase suction mode, then the effluent collection efficiency is improved, but the reliability of the system deteriorates due to damage from high temperatures and corrosive compounds

Engineering Contradiction:
Improveeffluent collection efficiencyVSAvoidsystem reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent replaces mechanical shutters or flaps with a water curtain system to increase suction mode. The water curtain is formed by spraying water through nozzles to create a barrier that seals the hooding opening, eliminating the need for mechanical moving parts that are subject to high temperatures and corrosive compounds. This substitution of mechanical system with a fluid-based system resolves the contradiction by maintaining collection efficiency while improving reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses a water curtain system where water is sprayed through nozzles to create a sealing barrier. This hydraulic approach replaces the mechanical shutter system, using fluid dynamics to achieve the sealing function. The water curtain is controlled by water supply pressure and flow rate, providing a reliable method to increase suction mode without exposing mechanical parts to harsh conditions.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Productivity

If a double suction system with separate duct networks is implemented, then the effluent collection efficiency is improved, but the device complexity and investment cost increase significantly

Engineering Contradiction:
Improveeffluent collection efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a dynamic water curtain system that can be activated or deactivated based on operational needs. The water supply to the nozzles can be controlled to create or dissipate the curtain, allowing the system to adapt between normal operation and increased suction mode. This dynamic approach maintains simplicity of the overall system while providing the capability for enhanced collection efficiency when required.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the state of the hooding opening by introducing a water curtain instead of physically blocking it with mechanical shutters. By controlling water flow parameters (pressure, flow rate) through the nozzles, the system can create a sealing barrier that maintains effluent collection efficiency without requiring complex mechanical structures or separate duct networks.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If hoods or doors are opened for tending operations, then the accessibility for maintenance is improved, but the effluent collection efficiency deteriorates due to reduced confinement

Engineering Contradiction:
Improveaccessibility for maintenanceVSAvoideffluent collection efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent introduces a water curtain as an intermediary element between the opened hooding and the external environment. The water curtain acts as a temporary seal that allows maintenance personnel to access the cell while still confining effluents. The curtain is positioned at the opening and creates a barrier that maintains collection efficiency even when the hooding is open for tending operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary anti-action by creating a water curtain barrier before effluents can escape when the hooding is opened. The water is sprayed to form the curtain in advance, preventing the loss of effluent confinement that would normally occur when hoods or doors are opened for maintenance. This preliminary barrier maintains collection efficiency throughout the maintenance operation.

Inventive Principle:
Principle #9Preliminary anti-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 solution effectively increases the gas flow rate in outlet channels, enhancing effluent collection efficiency while minimizing mechanical component exposure to harsh conditions and reducing investment costs by avoiding complex mechanical systems.

Implementation Method 1

a first end that is directly or indirectly connected to a pressurized air supply and a second end that is located inside said at least one outlet channel, includes at least one aperture and is oriented so that pressurized air can be projected through said aperture in a manner that increases the rate of said flow of gas within said at least one outlet channel

Methodology Applied
Scientific EffectPressurized air flow: Pressure Gradient

Data Source

PatentEP1845175B1System and process for collecting effluents from an electrolytic cell
Publication Date: 2011.02.16 PECHINEY RHENALU
  • EP1845175B1 patent drawingFigure 1
  • EP1845175B1 patent drawingFigure 2
  • EP1845175B1 patent drawingFigure 3

AI summary

The invention provides a system and a process for collecting effluents produced by an electrolysis cell (1) intended for the production of aluminium and for drawing said effluents away from the cell in a flow of gas. The system comprising a hooding (20) to confine the effluents, at least one outlet channel (25) to collect said flow of gas and suction means to draw said flow of gas away from the cell. The hooding (20) includes removable hoods (21) and, optionally, at least one door (23) to get access to the inside of the hooding. The system further comprises at least one pipe (50) for blowing pressurized air within the outlet channel (25) so as to increase the rate of said flow of gas. Pressurized air supply (53) is activated at a specified pressure Po so as to obtain a specified flow rate Ro.