Municipal Waste Shredding and Density Separation for Engineered Fuel

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Solution Overview

Problem

The increasing scarcity and cost of fossil fuels have led to a need for alternative, efficient, and clean fuel sources, as well as effective waste management systems that can reduce greenhouse gas emissions by utilizing municipal solid waste as an energy source, while minimizing environmental pollutants from combustion processes.

Innovation Solution

A system and method for processing municipal solid waste by separating non-processable waste, shredding and classifying constituents, and incorporating additives to produce an engineered fuel feedstock, which includes a multi-material processing platform with shredders, separators, and a material classification subsystem to create a homogeneous fuel feedstock for efficient combustion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If municipal solid waste is used as fuel source, then alternative fuel supply is improved, but greenhouse gas emissions and environmental pollutants increase

Engineering Contradiction:

Improvealternative fuel supplyVSAvoidgreenhouse gas emissions

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The waste stream is segmented into different density fractions through multi-stage separation processes. Heavy materials (density >15 lb/ft³) are separated from medium-density materials (4-15 lb/ft³), which are further separated from light materials (density <4 lb/ft³). This segmentation allows selective processing and blending of waste components to create an engineered fuel feedstock with optimized combustion characteristics and reduced emissions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The physical state and composition parameters of the waste material are changed through size reduction (shredding to uniform particles), density-based separation, and controlled blending. These parameter changes transform heterogeneous waste into a homogeneous engineered fuel with consistent caloric value and reduced harmful emissions during combustion.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If waste stream is processed through multiple separation stages, then fuel quality is improved, but processing complexity increases

Engineering Contradiction:

Improvefuel qualityVSAvoidprocessing complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Complex mechanical separation systems are replaced with density-based separation using fluidized beds or air classification. This substitution simplifies the processing equipment while maintaining high separation precision, reducing mechanical complexity while achieving consistent fuel quality through physical property differences rather than complex mechanical sorting.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If waste constituents are reduced to uniform particle size, then combustion efficiency is improved, but energy consumption increases

Engineering Contradiction:

Improvecombustion efficiencyVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

Waste materials undergo preliminary size reduction and classification before combustion processing. By pre-shredding and classifying particles to uniform sizes, the combustion process operates more efficiently with consistent burn rates and complete combustion. This preliminary action reduces the energy demand during the actual combustion phase, as uniformly sized particles ignite and burn more predictably and completely.

Inventive Principle:

Principle #10Preliminary 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 approach enables the production of a clean and efficient engineered fuel feedstock that reduces greenhouse gas emissions and operational costs, while effectively utilizing waste materials, thereby addressing the challenges of fossil fuel scarcity and environmental pollution.

Implementation Method 1

a processing apparatus configured and disposed to receive constituents of the municipal solid waste stream from the processing sub-system and reduce the size of the constituents of the waste stream to an average particle size of less than about 3⁄4 inch

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

separators configured to sort the waste stream into constituents based on density

Methodology Applied

Scientific EffectDensity: Density Gradient

Data Source

PatentUS8746599B2Systems and methods for processing a heterogeneous waste stream

Publication Date: 2014.06.10 ACCORDANT ENERGY LLC

AI summary

Systems and methods for processing and sorting a municipal solid waste stream are described herein. A system can include a processing sub-system configured to receive a municipal solid waste stream and to remove the non-processable waste, a processing apparatus configured and disposed to receive constituents of the municipal solid waste stream from the processing sub-system and reduce the size of the constituents of the waste stream to an average particle size of less than about ¾ inch, and separators configured to sort the waste stream into constituents based on density.