Characterizing and Modeling Mechanical

Properties of Biomass Harvesting and Processing

Shuai Zhang

Ag. And Biological Eng. Dept.

Pennsylvania State University

Background

• Renewable Revolution: Bioenergy

• Energy Crops: Miscanthus and Switchgrass

• Machine and Field Efficiency

• Energy Consumption

Background

Biomass Harvesting and Handling

Miscanthus Harvester

High Efficiency

Harvest Time

Loading Force

Bulk Density

Energy Consumption

Machine Speed

Biomass Type & Quality

Goal

• The goal of this research is to quantify main design parameters of biomass handling machines through experimental studies for engineers to find innovative solutions of increasing machine efficiency and field capacity.

Objectives

• Static and dynamic properties on cutting, bending, and compression processes

• Energy consumption requirements and mathematic models

• Mechanical behaviors of bulk densification process

• Quality of bulk densified energy crops

Hypothesis

• H1: Loading speed and type of tools changes• H2: Moisture content and maturity of energy

crops • H3: Diameters, special mass and node or

internode • H4: The biomass additives • H5: The bulk density of compressed materials

Methodology (Overview)

Material collection

and compositio

n test

Mechanical properties

test : cutting, bending,

compression

Densification test with additives

and energy consumptio

n model

Quality monitor

Material Collection

Agronomy Farm of Pennsylvania State University

Julian, Center Country, Pennsylvania

Aging: Select Harvest Time

• Highest yield: August or September• Nutrient remobilization: November to March• Aging: Composition change-lignin and cellulose

change• Mechanical Properties• Conversion and machine efficiency during

harvesting

Composition Test

Energy Crop

Cellulose

Hemicellulose

Lignin

Ash

Other

Physical Characteristics

• Biomass handling and delivering

Moisture content

Bulk density

Diameter and height

Specific mass

Mechanical Properties

• Force or stress that the material withstand and resisted

• Cutting: max. stress• Bending: Young’s modulus: max. bending stress;

yield point• Compression : Compressive Stress; Energy• The relationships of factors

Cutting Test

Harvester cutting mechanism

Cutting Test

• Cutting Tool and Load

• Cutting Speed: Static

• New and Used Blades

• Sickle and Mower Blades

Device for Dynamic Testing

Tool Adjustable Weight

Height to control the end velocityCrop

sample

Shock absorber

Cutting Test

• Characteristics of Energy Crops

• Maturity

• Node and Internode

Cutting Test

• Loading speed: static: 5 in/min

dynamic: 18000 in/min

• Measurement: Cutting force; Displacement; Diameter

• Calculation: Max. cutting force, max. Stress

• Energy consumption

Bending Test

Round Baler

Bending Test• • Load Cell

SupportPVC

Bending Test

• Maturity• Diameter

Bending Test

• Loading speed: 1 in/min

• Measurements: Bending force; Displacement 

• Calculation: Bending stress;

Bending energy consumption;

Young’s modulus

Compression Test (single stem)

Compression behavior

Compression Test

• Loading speed: 0.8 in/min

• Measurement: Compression force; Displacement

• Calculation: Compressive stress

• Compressive energy consumption

Compression Test

• Yield point

• Deform elastically

• Deform plastically

• Non-reversible

Compression Test (Bulk densification)

• Bulk densification• Maturity-Mass• Additives

Compression Test (Bulk densification)

• 10% volume Grind Sugarcane; 10% Grind Corn

Stover

• Sugarcane Sugar Combination

Lubricant

• Corn Stover Ash: Silicon Dioxide

Calcium Oxide

Compression Test

• Bulk Densification

• Loading speed: 10 in/min

• Measurement: Compression Force;

Volume

• Calculation: Compressive Stress ； Energy Consumption;

Bulk Density

 

Composition Test

• Composition of original crop samples when collected

• Composition change after densified with Additives

• Component promotes densification• Cellulose, Hemicellulose, Lignin,and Ash

Quality Test

• Moisture content• Bulk density; Decay rate

• Monitor per month during one year period

under different storage conditions

Data Analysis

• Force-displacement Curve• Energy Consumption

0.15 0.2040.2580.3120.3660.4250.4790.5370.5910.6450.6990.7540.8080.86205

101520253035404550

Displacement (in.)

Cutt

ing

forc

e (lb

s)

Data Analysis

• Average Maximum Force-displacement Curve

• Diameter

• Strength

0

50

100

150

200

250

300

0.12 0.146 0.173 0.2 0.226 0.254 0.28 0.308

Aver

age

Max

Forc

e (N

)

Crosshead Displacement (m)

Cutting Bending Compression

Data Analysis and Expected Result

• Factors affecting Force and Energy• Used and New Knife for Cutting

bcdabc

abcd

bcd

bcdecdef

efghefgh

ghfgh

a abbcde

cdefdefg

efghefgh

fgh fgh

gh

0

100

200

300

400

500

600

1 2 3 4 5 6 7 8 9 10

Aver

age

Cutti

ng Fo

rce

(N)

The order of cutting from the bottom of the plant

New knife Blunt knife

Data Analysis and Expected Result

e

dede

de

bcdbcd

de

abc dede cd

bcd

ab aba

0

100

200

300

400

500

600

700

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Aver

age

Max

Com

pres

sion

Forc

e (N

)

The order of samples from the bottom of the plantComparison of max compression forces(sample length: 100 mm)

Samples at Different Heights of the Stem

Energy Model Development

Factors of Bulk Densification

bulk density

particle size

maturity

loading speedadditives

temperature

moisture content

Prospects

• Dynamic properties

• New additives (heating)

• Tensile properties