Biomass Fuel Pellets with Thermoplastic Binder

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Solution Overview

Problem

Existing fuel pellets made from biomass have lower heating value and poor handling characteristics, making them unsuitable for coal-fired furnaces and industrial boiler applications due to difficulties in grindability and environmental concerns related to coal combustion.

Innovation Solution

Biomass-based fuel pellets are developed, comprising 5-15 wt.% thermoplastic polymeric material and at least 75 wt.% cellulosic material, formed by compression and extrusion, which infuses thermoplastic material into cellulosic fibers, resulting in pellets with improved grindability and handling characteristics, suitable for coal-fired furnaces and biomass boilers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If biomass fuel pellets are made from cellulosic material alone, then they are environmentally friendly and renewable, but they have poor handling characteristics and low heating value

Engineering Contradiction:
Improveenvironmental impactVSAvoidhandling characteristics
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent combines cellulosic biomass material with thermoplastic polymeric material to create a composite fuel pellet. The thermoplastic component (5-20% of total weight) acts as a binder that improves pellet durability and handling characteristics while the majority cellulosic content (80-95% of total weight) maintains the renewable and environmentally friendly properties. This composite approach resolves the contradiction by integrating the advantages of both materials.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the physical and chemical parameters of the fuel pellet by controlling the moisture content (5-15%), density (30-45 lb/ft³), and heating value (9,500-11,000 Btu/lb) through the addition of thermoplastic material and optimized compression processes. These parameter changes improve handling characteristics while maintaining environmental benefits.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If biomass fuel pellets are made with higher density, then heating value increases, but grindability decreases

Engineering Contradiction:
Improveheating valueVSAvoidgrindability
Core Design Contradiction:
Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent optimizes the density parameter to a specific range (30-45 lb/ft³) that balances heating value and grindability. By controlling density within this range and adjusting moisture content to 5-15%, the patent achieves adequate heating value (9,500-11,000 Btu/lb) while maintaining acceptable grindability for pulverized coal-fired boilers.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates local quality variations within the pellet structure through the thermoplastic binder distribution, where the binder provides localized binding strength in critical areas while maintaining overall porosity and density characteristics that facilitate both high heating value and acceptable grindability.

Inventive Principle:
Principle #3Local quality

3Reliability

If thermoplastic polymeric material is added to improve pellet durability, then handling characteristics improve, but the proportion of cellulosic material decreases

Engineering Contradiction:
Improvepellet durabilityVSAvoidcellulosic material content
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent creates a composite formulation where thermoplastic polymeric material (5-20% of total weight) serves as a binder to improve pellet durability and handling characteristics. The majority composition remains cellulosic biomass (80-95% of total weight), ensuring the fuel maintains its renewable and environmentally friendly properties while achieving the desired mechanical strength for commercial handling and transportation.

Inventive Principle:
Principle #40Composite materials

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 biomass-based fuel pellets achieve a minimum heat value of 9,500 Btu/lb, retain good grindability, and have a high pellet durability index, similar to coal, reducing environmental impact and increasing efficiency in combustion systems.

Implementation Method 1

this may be accomplished by extrusion of the feed mixture, typically at a temperature at which the thermoplastic polymeric material is in a molten state

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

the biomass/polymer feedstock mixture is typically subjected to a pressure of no more than about 2,500 psi

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentUS8137420B2Densified fuel pellets
Publication Date: 2012.03.20 RENEWABLE DENSIFIED FUELS LLC
  • US8137420B2 patent drawing
  • US8137420B2 patent drawing
  • US8137420B2 patent drawing

AI summary

A method of producing a biomass-based fuel pellet, such as a fuel pellet which includes thermoplastic polymeric material and a substantial amount of cellulosic material, e.g. cellulosic material derived from biomass source(s), is provided. The method commonly includes compressing a feed mixture to form a densified material, where the feed mixture includes about 5 to 15 wt. % of the thermoplastic polymeric material and at least about 75 wt. % cellulosic material. Many embodiments of the fuel pellets are suitable for use in a coal-fired furnace and/or in other industrial boiler applications.