Pulp Washer Mist Eliminator Using Tangential Flow Impingement
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Solution Overview
Problem
Existing mist eliminators in pulp washers suffer from incomplete separation of gas and liquid, leading to contaminated airflow and reduced efficiency, as they struggle with dense foams and mists, which can damage equipment and impede the pulp washing process.
Innovation Solution
A gas/liquid separator system with a housing having a vertical centerline and a separation chamber that directs the gas/liquid flow at an angle, causing liquid particles to impinge on the chamber walls and coalesce, with a drain tube for separating liquids outside the receptacle, and optionally augmented by a vacuum source for enhanced drainage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a typical cyclonic separator is used to separate gas from gas/liquid flow mixture, then the gas mixture is drawn vertically upward and centrifugal force forces heavier particles radially outwardly, but the separation is incomplete and liquid particles continue to contaminate the gas flow
Solution Approach 1:
The separator is divided into multiple functional zones: an upper separation chamber with downwardly directed flow for initial liquid removal, and a lower cyclonic separation zone for heavier particle removal. This segmentation allows different separation mechanisms to work in sequence, improving overall separation completeness while preventing liquid contamination of the discharged gas.
Solution Approach 2:
Instead of drawing gas vertically upward as in typical cyclonic separators, this invention draws gas horizontally or obliquely through the separation chamber, causing liquid particles to impinge on chamber walls and coalesce. This inverted flow approach enhances separation effectiveness by utilizing wall impingement and coalescence mechanisms rather than relying solely on centrifugal force.
2Productivity
If air is drawn through the blower to create positive pressure in the pulp washer, then washing efficiency is improved, but liquid or solid particles become entrained in the air and damage the blower
Solution Approach 1:
The separator performs preliminary separation of liquid and solid particles from the air stream before the air enters the blower. By removing entrained particles in advance, the system protects the blower from damage while maintaining the high airflow rates needed for effective pulp washing operation.
Solution Approach 2:
The separation chamber acts as an intermediary device between the pulp washer and the blower. It mediates the airflow by removing harmful particles while allowing the necessary air flow to pass through, thus protecting the blower without compromising washing efficiency.
3Reliability
If wash liquid is used to achieve desired washing efficiency, then pulp cleaning is improved, but the recovered liquor becomes diluted and concentration costs increase
Solution Approach 1:
The separator efficiently discards wash liquid that becomes entrained in the air stream by capturing and coalescing liquid particles. This recovered liquid is then returned to the pulping liquor reservoir, preventing dilution losses and reducing the cost of concentrating liquor in the recovery process.
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 separates liquid particles from the gas flow, preventing contamination of the blower and improving the pressure differential, thus enhancing the efficiency and effectiveness of the pulp washing process by ensuring cleaner airflow and efficient liquid recovery.
Implementation Method 1
A cyclonic rotation is imparted to the flowing mixture, typically by means of helical or spiral vanes. Centrifugal force causes heavier particles to be forced radially outwardly toward the outer periphery of the flow mixture where the particles coalesce into liquid droplets and drop back downward under the force of gravity.
Implementation Method 2
a flow director providing gas/liquid flow entering the separation chamber in a direction not parallel to the centerline of the housing such that when a suction is drawn by the vacuum source, a mixture of gas and liquid particles is drawn into the gas/liquid inlet and directed into the separation chamber with the velocity and momentum of the liquid particles causing impingement on the wall of the separation chamber, coalescing the liquid particles into droplets
Implementation Method 3
coalescing the liquid particles into droplets which drain down the chamber walls by the force of gravity to a liquid drain
Data Source
AI summary
Method and apparatus for removing liquid from a gas/liquid flow for use in pulp washers, deinking cells, and the like are disclosed. A gas/liquid separator includes a separation chamber with a flow director providing a gas/liquid flow from a receptacle into the separator in a direction causing impingement of entrained liquid particles on a chamber wall such that liquid particles coalesce into liquid droplets that travel downward by the force of gravity to a separated liquid drain and drained outside the receptacle. A tangential flow inlet provides greater impingement than a cyclonic flow introduced at the lower end of the gas/liquid separator in initially directed upwards. Separated liquid could further be taken outside the pulp washer system for further processing or disposal based on the chemical content of the separated liquid.