Rotating Separator With Screw Press For Slurry Dewatering

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Solution Overview

Problem

Current methods for separating solids from slurries, such as those used in biogas plants, are inefficient as they leave a significant amount of liquid retained in the solid fraction due to reliance on gravity alone, resulting in a low percentage of dry matter in the separated solids.

Innovation Solution

A rotating container with a filter cloth and a screw press system is used, where the container rotates slowly to separate liquid from solids, and the screw press further presses the retentate to remove additional liquid, increasing the dry matter content through multiple filtrates and retentates, with optional use of a hydrocyclone for additional separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If gravity alone is used for separation, then the separation process is simple, but the dry matter content of separated solids remains low

Engineering Contradiction:
Improveseparation process simplicityVSAvoiddry matter content
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The separation process is divided into multiple stages: initial gravity separation in the rotating container, followed by mechanical pressing with a screw press, and optional hydrocyclone separation. Each stage targets different aspects of liquid-solid separation, progressively increasing dry matter content from ~5% to 30-40%.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple separation mechanisms are combined in sequence: gravity separation, mechanical compression, and centrifugal force. This hybrid approach overcomes the limitations of any single method, achieving both high dry matter content and reasonable process complexity.

Inventive Principle:
Principle #5Merging (Combining)

2Quantity of substance

If a rotating container with filter cloth is used, then liquid separation improves, but device complexity increases

Engineering Contradiction:
Improveliquid separation efficiencyVSAvoidseparator structure complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The container rotates slowly to utilize centrifugal force for enhanced liquid-solid separation. This dynamic element improves separation efficiency without requiring complex mechanical structures, as the rotation itself provides the separating force.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A filter cloth is used as a porous medium to physically separate liquid filtrate from solid retentate. The porous structure allows liquid to pass through while retaining solids, improving separation efficiency with a relatively simple component.

Inventive Principle:
Principle #31Porous materials

3Quantity of substance

If screw press is added to increase dry matter content, then separation efficiency improves, but energy consumption increases

Engineering Contradiction:
Improvedry matter contentVSAvoidenergy consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The rotating container with filter cloth performs preliminary liquid removal before the screw press operation. This pre-separation reduces the volume of material requiring mechanical pressing, thereby lowering the energy consumption of the screw press while still achieving high dry matter content.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system maintains continuous operation with the rotating container constantly separating liquid and solids, and the screw press continuously processing the retentate. This continuous action maximizes separation efficiency while minimizing idle energy consumption.

Inventive Principle:
Principle #20Continuity of useful 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

The method significantly increases the dry matter content of the separated solids from approximately 5% to 30-40%, allowing for more efficient energy use and improved handling of the slurry, while also reducing the phosphorous content in the filtrate for environmentally sensitive areas.

Implementation Method 1

a rotating container (103) with a filter cloth... the container rotates slowly to separate liquid from solids

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Implementation Method 2

the screw press further presses the retentate to remove additional liquid

Methodology Applied
Scientific EffectMechanical compression: Compression

Implementation Method 3

separates solids from liquid matter by means of gravity alone

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP2827964B1Rotating separator
Publication Date: 2019.10.23 PURFIL APS
  • EP2827964B1 patent drawingFigure 1
  • EP2827964B1 patent drawingFigure 2
  • EP2827964B1 patent drawingFigure 3a~3b

AI summary

This invention describes a separator for separating solids from a slurry comprising a vibrating rotating container, rotatably connected to a support, where the rotating container is provided with at least a first inlet and at least a first outlet and comprises at least one opening. A screw press is at least partly provided inside said rotating container, where said screw press is arranged through said first outlet and said screw press comprises at least one hole; said at least one hole, a feed screw being provided inside said rotating container in continuation of said screw press and at least one lift paddle being provided inside said rotating container, where a first part of said lift paddle is arranged along an inner surface of said side wall of said rotating container and a second part of said lift paddle is in contact with a part of said feed screw. The invention further describes a method for separating slurry using a separator.