Chemistry in Combustion Processes I

Introduction

Åbo Akademi University

Chemical Engineering

Laboratory of Inorganic Chemistry

Energy in Finland: 80 % Combustion

Import of Power

Others

Peat

Wood Fuels

Hydro

Nuclear

Natural Gas

Coal

Oil

Finland

• Leading in the use of bioenergy

• Leading in combustion engineering:

- biofuels: fluidised beds

- pulping spent liquor (black liquor) combustion

- large Diesel engines

• Extensive research and development activities

Alholmen Power Plant

ALHOLMEN FLUIDISED BED BOILER 550 MW (545 °C) Peat, Bark, REF, Forest Residue, Sawdust, Coal, Oil Boiler Efficiency 92 % SO2 100 mg/MJ NOx 50 mg/MJ Particulate 30 mg/m3n

Kvaerner Power Oy - 2001

Capacity of FBC Boilers World-wide 2003

0

10

20

30

40

50

60

70

1975 1980 1985 1990 1995 2000

Year

Cu

mu

lati

ve c

ap

acit

y [

1000 M

Wth

]

CFBC

BFBC

PFBC

FBG

Use of

Wood in

Finland

(VTT 2000)

Use of

Wood in

Finland

(VTT 2000)

Black Liquor – An Energy Rich

Byproduct at Pulp Mills

Tomlinson Boiler, 1937 Wisaforest, 2004

85 m

15 m

Fray Bentos, Uruguay (Andritz)

Hainan Jinhai, China (Valmet 2007)

Black Liquor Recovery Boilers 1937-

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

Delivery year

Ca

pa

city, t D

S/d Daily Capacity

ton Dry Solids

Research in combustion engineering

• Environmental challenges

• Efficiency

• ”New” fuels: biofuels, waste derived fuels,

fuel mixtures

• Fundamental understanding of the processes

• More chemistry

100 %

100 ppm

1 %

1 ppm

1 ppb

(µg/kg)

1 ng/kg

1 pg/kg -15

CO2 Carbon Dioxide

CO Carbon Monoxide / CxHy Hydrocarbons

PAH Polyaromatic Hydrocarbons

As, Cr, Ni, V, Pb, Cd, Hg,... Heavy Metals

Dioxins, Furans

SO2 Sulfur Dioxide / NOx Nitrgen Oxides

-5

-10

0

Environmental challenges - Flue Gas Emission Components

Research in combustion engineering

• Environmental challenges

• Efficiency

• ”New” fuels: biofuels, waste derived fuels,

fuel mixtures

• Fundamental understanding of the processes

• More chemistry

Biofuels – Waste derived fuels – “Opportunity fuels”

Forest residues Annual crops

Prunings Shells, husks & hulls

Olive stones RDF (refuse derived fuels)

Waste sludges MBM (meat and bone meal)

Chicken litter Coal Slurry Pet coke

Åbo Akademi Fuel Data Bank

This Course Introduces...

• Industrial-scale combustion systems

• Chemistry of emission components

• A ”Process Chemistry Toolbox” for theoretical

analysis of combustion processes