Lecture 11 Biomass III

RENEWABLE ENERGIES

2023284

Period: 2011-1I

Biomass III

Course Schedule

Introduction

Densification Fundamentals

Market data

Manufacture process

Energy from pellets

Environmental assessment

Renewable Energy .- Thermodynamics I. Carlos Andrs Forero. Sept 2011

2

Introduction

Why do we use biomass for energy

production???

What are some problems related with

biomass use???


3

Introduction

Biomass has so many benefits related with:

GHG Emissions reduction

Energy supply security

Small scale power systems

Biomass has problems in terms of:

Storage

Transportation

Transformation

Low efficient processes


4

Fundamentals

Densification of biomass is a process of

reducing the bulk volume of the material

by mechanical means.

Final products are called pellets or

briquettes


5

Fundamentals

Pellets and briquettes are high density biomass

products, with low moisture content which

could be distinguished by their dimensions


6

Fundamentals

Pellets are cylindrical solids which diameter is about 5 10 mm and length about 8 29 mm

Briquettes are cylindrical solids which diameter varies between 40 to 90 mm and the length is between 74 to 300 mm

Advantages: Ease of handling and storage Improve biomass stability Facilitates the feeding of solid biomass fuels to

furnaces

Clean burning High energy density


7

Fundamentals

Volume required to substitute one cubic

meter of oil by some other fuels


8

Fundamentals

Most of pellets and briquettes are produced from wood, but there are new raw material such as agricultural or coal residues, these solid biofuels are called Mixed Biomass Pellets

Wheat straw, barley straw, corn stover

Swtichgrass

Alfalfa

Palm oil

Rice straw, rice bran


9

Fundamentals

There are no standardized quality

parameters but some countries define

particular norms.

norm M1735 (Austria)

DIN 51731 (Sweden)

SS 187120 (Germany)

CEN/TS 14961:2005


10

Fundamentals

Basic specifications

Renewable Energy .- Thermodynamics I. Carlos Andrs Forero. March 2011

11 Source: European pellet center

Market data

Wood pellets consumption have increased the

last 5 years more than 200%


12

Market Data

Europe

Prod. 7 mill

Con. 8 mill


13

Market Data

Rest of the world


14

Market Data

Why do you think European countries consume

and produce most of the wood pellets???

Do they have enough biomass potential???


15

Manufacture process

General wood pellet process


16

Manufacture process

More detailed process


17

Manufacture process

Plant Lay out

Renewable Energy .- Thermodynamics I. Carlos Andrs Forero. March 2011

18

Manufacture process


19

Cleansing:

After drying several impurities could be mixed with biomass

such as metals; therefore they must be removed using

magnets and screens

Grinding:

The size of the biomass must be homogeneous, typically size

is below 5 mm

Pressing:

Raw material raw lies in a layer in front of a rolling press,

which presses the material down into the die block.

1 or 2% of steam is injected before the biomass goes into

the pelletising machine

Manufacture process


20

Pelletising machine with ring die block.

Diagram of the plane type die block

Manufacture process


21

Parameters:

- Pressure

- Temperature

- Moisture

- Particle size

- Fibers

- Proteins

- Starch

- Lignin

- Oil and wax

Manufacture process


22

SEM (Beech at 25 and 100C)

Source: Stelte,

Biomass and Bioenergy 35 910 - 918

Manufacture process


23

UV-AF microscopy

(corn stover before and after)

Lignin: brilliant blue, bluish white

Proteins: green or yellow green

Carbohydrates: black

Source: Kaliyan, Bioresource

Technology 101 1082 - 1090

Energy from Pellets

We could use pellets either for electricity

production or thermal energy generation


24

Energy from pellets

Bulk power


25

Long term contracts

needed

Especially used at

co-firing plants

Energy from pellets

District heating


26

Energy from pellets

Residential heating


27

Energy from pellets

Residential Heating


28

Small bags: max 25 kg

Big Bags of up to 1200 kg

Energy from pellets

Electricity production

There is not any medium scale power plant which operates only with biomass pellets.

Avedore (300.000 tonnes/year)


29

Energy from pellets

Pellet stoves for residential heating


30

Energy from pellets

Residential Heating


31


Energy consumption at the procurement

and use of wood pellets


32


Energy consumption of other fuels


33

Fuel Energy consumption

MJ/tonne % of energy content

Native wood

pellets 627 3,6

Imported wood

pellets 787 4,5

Natural Gas 2840 5,8

Oil 4617 11,4

Coal 1764 6,7


GHG Emissions


34


GHG Emissions compared with other

fuels


35

Fuel

Substance

Wood

pellets

Straw Fuel Oil Natural

Gas

CO2 g/MJ 0,108 0,108 0,972 0,72

SO2 g/MJ 0 13 94 0,5

CO mg/MJ 50-3000 500-3000 15-30 15-20

NOx mg/MJ 130 - 300 130 - 300 75 50 - 100

TOC mg/MJ

Documents

Lecture 11 Biomass III