Sludge Biofuel Pelletizing via Extrusion and Drying

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Solution Overview

Problem

Current methods for sludge disposal from wastewater treatment plants are costly due to energy requirements for drying, transportation, and disposal, and lack efficient utilization of the sludge's energy potential, with existing solutions like composting and heat treatment being inefficient and environmentally burdensome.

Innovation Solution

A process that mixes drained sludge with dry or semi-dry organic fuels, using a combination of mixing, extrusion, and drying to produce compact biofuel suitable for existing combustion installations, utilizing activated charcoal to minimize odor emissions and create a clean, renewable energy source.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If sludge is disposed of at dumps or through traditional methods, then disposal is achieved, but high costs for energy, transport, and disposal arise while the energy potential of sludge remains unused

Engineering Contradiction:
Improveenergy potential of sludgeVSAvoidcomplexity of disposal process
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent converts sludge, traditionally viewed as a waste product requiring costly disposal, into a valuable biofuel resource. By mixing sludge with organic fuel materials and processing through extrusion and drying, the system transforms the harmful waste into a beneficial energy source that can be used in existing combustion installations, thereby recovering the energy potential that would otherwise be lost.

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

Solution Approach 2:

The patent enables sludge to serve its own purpose as a fuel source rather than requiring separate disposal infrastructure. The processed biofuel can be used in existing combustion installations, making the system self-sufficient and eliminating the need for specialized disposal devices or infrastructure.

Inventive Principle:
Principle #25Self-service

2Weight of moving object

If sludge is mechanically dried to reduce mass and volume, then transport and disposal costs are reduced, but high drying energy costs are incurred

Engineering Contradiction:
Improvemass of sludgeVSAvoiddrying energy cost
Core Design Contradiction:
Weight of moving objectVSUse of energy by moving object

Solution Approach 1:

The patent combines sludge with organic fuel materials during the mixing stage, creating a composite biofuel product. This merging allows the sludge to be processed into a compact, transportable form without requiring extensive mechanical drying, as the organic materials contribute to the fuel's energy content and the extrusion process naturally reduces moisture content through compression and shaping.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the physical and chemical parameters of sludge through the extrusion and drying process. The extrusion process compresses the mixture and shapes it into pellets or briquettes, significantly reducing volume and improving transport efficiency. The subsequent drying process, operating at moderate temperatures, further reduces moisture content to achieve the desired fuel specifications without incurring excessive energy costs.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If sludge is composted with greenery waste, then biological fertiliser is produced, but the energy potential of sludge is not utilized and disposal costs remain high

Engineering Contradiction:
Improveproduction of fertiliserVSAvoidenergy potential of sludge
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

Instead of composting sludge to produce fertiliser (the traditional approach), the patent inverts the approach by processing sludge into biofuel for energy production. This inversion allows the energy potential of sludge to be captured and utilized, while the byproduct can still be used as a soil amendment or disposed of more easily due to reduced volume and stabilized composition.

Inventive Principle:
Principle #13The other way round (Inversion)

4Adaptability or versatility

If sludge is mixed with organic fuel materials, then biofuel is produced that can be used in existing installations, but additional processing equipment is required

Engineering Contradiction:
Improvecompatibility with existing combustion installationsVSAvoidprocessing equipment required
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates a multi-functional processing system that produces biofuel compatible with existing combustion installations. The mixing, extrusion, and drying equipment can process various types of sludge and organic fuel materials, producing a versatile biofuel product that can be used in different applications. The system is designed to work with standard combustion technologies, eliminating the need for specialized infrastructure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 process reduces the costs associated with sludge disposal by converting sludge into a clean, renewable biofuel that can be easily transported and used in existing infrastructure, minimizing odor emissions and enabling large-scale recycling of sludge into a valuable energy source.

Implementation Method 1

the odour emissions in the mixing phase is minimal due to absorption effect of active charcoal and organic matter

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

The drained sludge (1) and dry and semi-dry organic fuel (4) are transported by a transporting device (6) into a mixer (8), followed by an extruder (10)

Methodology Applied
Scientific EffectExtrusion: Extrusion

Implementation Method 3

followed by an extruder (10), then into a granulator with the drying function (12) and a dryer (14)

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4257559A1A process for producing biofuel from wastewater treatment sludge
Publication Date: 2023.10.11 EKO D O O KRSKO
  • EP4257559A1 patent drawingFigure 1
  • EP4257559A1 patent drawingFigure 2
  • EP4257559A1 patent drawing

AI summary

The process for production of biofuel from the wastewater treatment plant sludge which comprises mixing drained wastewater treatment plant sludge with added dry and semi-dry organic fuel, such as wood waste, plant straw, sawdust, charcoal powder, etc., extrusion during the phase of mixing the generated material, shaping the material, generally into granules, briquets and pellets, and drying the produced biofuel. The drained sludge of wastewater treatment plants serves as a bonding agent during the fuel production according to the present invention. In view of the prior, the process has numerous economic advantages, since it makes use of drained sludge from wastewater treatment plants which represents a serious environmental issue, the invented technological process requires no special equipment to be constructed for this purpose, the biofuel produced on the basis of the present invention can be used in existing stoves for solid fuel, and in addition, this biofuel is clean fuel and renewable energy source.