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COMBUSTION AND FUELS
BIOMASS
COMBUSTION AND FUELS
WHY BIOMASS
Benefits of the use of biomass:�reduction of green-house effect�saving fossil fuels�reduction of costs of heat and electricity production�EU policy
In Poland:�7.5% of electricity will be produced from renewable energy resources in 2010 and 20% in 2020�biomass has a considerable potential in Poland
COMBUSTION AND FUELS
A little history about the use of biomassby a man
Biomass has been in use as a basic fuel from the prehistoric times. Since approx. 150 000 year a man has learned to apply firing using wood as a fuel.
In ancient times wood, animal and vegetable fats were basic energy resources in common use.
At present in some developing countries animalmanures and cow dung are still important fuels fordomestic use.
COMBUSTION AND FUELS
BIOMASS and GREEN-HOUSE EFFECT
CO2 conversion during biomass burning
PHOTOSYNTHESIS(PLANTS) COMBUSTION
BIOMASS BIOMASS CONVERSION
νh CO2 O2 CO2 HO2 O2HO2
COMBUSTION AND FUELS
ORIGIN OF BIOMASS
Vegetable biomass is formed in the process of photosynthesis in plants.
6CO2 + 6H2O + light → C6H12O6 + 6O2
The efficiency of solar energy conversion in the photosynthesis process is < 1%.
The effectiveness of agriculture is approx. 50 Mg/ha
COMBUSTION AND FUELS
Carbon conversion during combustion of biomass
COMBUSTION AND FUELS
TYPES OF BIOMASS
Vegetable type:
- agriculture residues: straw, hay, husks, shells, bagasse, ...
- energy-cropping: fast growing plants for direct use as a fuel (e.g. poplar, willow, miscanthus)
- vegetable oils and alcohols.
Animal type
- animal manures and cow dung,
- animal fats and bone flour.
COMBUSTION AND FUELS
ENERGY-CROPPING
WILLOW
COMBUSTION AND FUELS
POTENTIAL OF RENEWABLE ENERGY RESOURCES: WORLD
TWa
biomass 6
energy of water 3
energy of wind 3
geothermal energy 2
heat of oceans 1
kinetic en. of seas and oceans 0.045
small-scale solar installations 2.2
TOTAL 17.245
POTENTIAL OF RENEWABLE ENERGY RESOURCES: POLAND
Sourceof energy
Biomass
Water
Geothermal
Wind
Sun
Total
Totalconsumption
of primary energyin Poland (1998)
COMBUSTION AND FUELS
RESERVES OF BIOMASSIN POLAND
COMBUSTION AND FUELS
RESERVES OF BIOMASS IN POLAND Source of biomass Type of biomass Resources, PJ
Agriculture production Hay, straw 150
Wood and forestindustry
Wood residues 73
Paper industry lignin, wood residues 11
Municipal activity Municipal residues 60
Sewage sludge Sludge 1-1.5ms mln t
Rapeseed cultivation Rapeseed oil, methyl esther 24
Total: 300 PJ
COMBUSTION AND FUELS
Reserves of biomass – straw (price approx. 80 zł/t)
S – ratio of main product weight to the straw weight
CropsMain product
(grain)Aside product
(straw)S
WheatRyeBarleyOatMaize (Corn)
graingraingraingraingrain
strawstrawstrawstrawstraw
1.31.161.21.31.0
On the basis of total grain cultivation the straw production is estimated at 450 PJ
in Poland. Only 10% could used for energy production.
Distribution of straw in Poland
x 103 t of straw
COMBUSTION AND FUELS
Reserves of biomass – wood
– forests (5900 dam3),
– wood industry (1110 dam3),
– parks (265 dam3),
– orchards (1000 dam3),
where: dam3 = 1000 m3.
Annual production of wood, which can be used for energy production, is estimated on 8265 dam3, corresponding to 68.3PJ (without energetic cropping).
Distribution of wood in Poland
x 103 t of forest wood
Distribution of energetic crops in Poland
x 103 t of crops
COMBUSTION AND FUELS
Reserves of biomass – rapeseed oil
Annual production of rapeseed oil in Poland is:
•1.6 mln Mg
From 1 Mg of raw rapeseed it can be obtained:
•0.4 Mg of rapeseed oil
The ability of rapeseed cropping for the energy production is estimated in Poland at 1 mln Mg, which corresponds to approx. 30 PJ.
COMBUSTION AND FUELS
Reserves of biomass – ethanol i methanol
Ethanol is produced by the alcohol fermentation of corn and potato.
Methanol is manufactured by chemical synthesis from gas or coal.
The ability of ethanol production from plants for energy generation is estimated at 1 mln Mg, which corresponds to approx. 22 PJ.
COMBUSTION AND FUELS
Reserves of biomass – gaseous fuels (biogas)
Types of gaseous fuel (biogas):
- product of methanation of: animal manures, cow dung and crop residues,
- „methane” from refuse dump,
- product of biomass gasification (wood).
Estimated potential: 16 PJ
COMBUSTION AND FUELS
Comparison of some parameters of biomassand fossil fuels
FuelC%
H %
O%
N + S
%LCV
MJ/kgVolatilematter
%
WoodLigniteHard coalPetroleumNatural gas
5070828986
655
8,46,5
4324122
0,1
0.30..80.80.60.1
14,521304748
755035--
1.5 Mg of wood corresponds to 1Mg of coal
Comparison of properties of different types of biomass
BiomassLCV
MJ/kgDensityg/cm3
Moisture%
Ash%
Corn strawSoya strawHusks of maizeStalks of maizeWood residuesHaySawdustOak woodPine woodBirch woodDry sewage
14.414.615.214.615.98–916.814.316.715.9
10–12
1.3–1.361.3–1.351.01–1.30.1–0.50.1–0.50.1–0.30.92–1.1
0.61
6.28.76.1
30–5016–588–356.11312123.1
4.86
6.5
1.4
10–123.60.2
30–40
COMBUSTION AND FUELS
STRAW
COMBUSTION AND FUELS
Analysis of selected types of straw
Typeof
straw
Moist.in rawstraw,
%
Ash,%
LCV(Wu)dry
strawMJ/kg
LCV(Wu)raw
strawMJ/kg
C H O N S
WheatBarleyMaizeRape
12–2212–2250–7060–70
6.54.35.74.6
17.316.116.8
–
12.9–1512.0–143.3–7.2
–
49464747
5665
39384040
0.30.40.80.8
0.10.10.10.1
COMBUSTION AND FUELS
Properties of straw
Main compound of straw: cellulose (C6H10O5)n
Advantage of straw as a fuel:- considerable LCV and small content of sulphur.
Disadvantage of straw as a fuel:- considerable content of potassium (K) and chlorine (Cl), low density, distribution and moisture.
COMBUSTION AND FUELS
Density and LCV depending on the form of straw
Straw form Bulk densitykg/m3
LCVMWh/m3
LooseChaffRound balesBales of high squeeze
Briquettes
20–5040–6060–9050–110300–450
0.07–0.160.13–0.190.19–0.290.16–0.360.99–1.48
COMBUSTION AND FUELS
Cost of pressing and handling of straw:80 PLN per Mg
COMBUSTION AND FUELS
Bales of rape straw
COMBUSTION AND FUELS
WOOD
Wood chips
COMBUSTION AND FUELS
Characteristic of wood as a fuel
Wood size:
wood chips, chunks, shreds, bark,pellets, sawdust and powder.
Advantage of wood as a fuel:
- small content of ash and
- practically lack of sulphur.
COMBUSTION AND FUELS
Types of wood fuel
post-felling remains
firewood type S4
small wood type M1
COMBUSTION AND FUELS
Shapes of wood – as a fuel
post-felling wastes type M2
baled post-felling wastes
wood from roadsides
COMBUSTION AND FUELS
Main compounds of wood
Wood components:
•holocellulose (cellulose and chemicellulose)
•Lignin
•Ash (1-3%)
•Moisture (12-22%)
COMBUSTION AND FUELS
Ultimate and proximate analysis of wood
Dry basis (d)
Woodtype
Proximate analysis Ultimate analysis, %
Volatilematter
%
Char%
Ash%
LCVMJ/kg
C H O N S
OakPineSpruceAldPoplar
85.682.287.087.188.0
13.015.012.712.511.0
1.42.80.30.40.7
18.724.322.019.319.1
4959505152
6.07.25.86.36.3
4433414242
0.2–
0.1––
0.02–
0.1––
COMBUSTION AND FUELS
Bark
Bark is a basic residue fuel from cellulose-paper industry.
LCV (d) of bark of selected trees
Wood type Ash%
LCVMJ/kg
Oak 5.3 19.5
Pine 2.9 21.0
Spruce 0.8 20.3
Redwood 0.4 19.4
COMBUSTION AND FUELS
ENERGETIC CROPS
COMBUSTION AND FUELS
Characteristics of energetic crops
General characteristics of energetic crop:
• fast growing plants
• long-term efficiency of plantation
• insects and illness resistance
• economics of cultivation
COMBUSTION AND FUELS
Examples of energetic plantsTrees:
• Willow
• Sunflower
• Pensylvanian mallow (malwa pensylwańska)
• Multiflora Rose (róża wielokwiatowa)
• Sakhalin Knotweed (rdest sachaliński)
Long-term grasses:• Miscanthus giganteus
• Miscanthus sacchariflorus
• Prairie cordgrass(spartina preriowa)
COMBUSTION AND FUELS
Energetic willow
COMBUSTION AND FUELS
RESIDUAL AGROCULTURE BIOMASS
COMBUSTION AND FUELS
Examples of residual agriculture biomass
łuski słonecznika
łuski orzechów
kaczany kukurydzy
śruta rzepakowa
pestki owoców
pestki oliwek
wytłoki po jabłkach
• sunflower hulls
• nut shells
• corn cobs
• ground rapeseed
• fruit seeds
• olive seeds
• apple pomace
COMBUSTION AND FUELS
Scheduled use of biomass in Polish heat and power industry
x 103 t
Agriculture biomass will be 60% of used biomass in 2014
COMBUSTION AND FUELS
Economic of heat generation using biomass
Price of raw biomass = 120-160 PLN per Mg
Price of 1 GJ of heat generated from biomass: 15-25PLN per GJ
COMBUSTION AND FUELS
Biomass as a fuel - summary
1. Most of biomass fuels have small bulk density: 300−700 kg/m3.
2. Most of biofuels have considerable content of water (30−55%).
3. Main components of plant biomass are: cellulose, homocellulose& lignin.
4. Biomass practically doesn’t have sulphur (wood and straw).
5. Biomass may have a considerable content of chlorine (straw).
5. LCV of dry biomass is 15−24 MJ/kg.
6. Same types of biomass have small content of ash (wood)
7. Biomass has a considerable content of alkali metals decreasing the temperature of slaging.