by dr ku syahidah ku ismail adapted from cheng, j. (2010) biomass to renewable energy processes
TRANSCRIPT
Chapter 1:BIOMASS RESOURCES &
CHARACTERISTICS OF BIOFUELSBy
Dr Ku Syahidah Ku IsmailAdapted from Cheng, J. (2010) Biomass to
Renewable Energy Processes
Biomass Energy Technology
Renewable Energy vs Fossil Fuel Energy
Fossil fuel reserves are limited and will be depleted.
Burning fossil fuels causes environmental concerns eg. GHG emmission.
Energy from biomass releases CO2, but the CO2 is utilized for biosynthesis during the growth of biomass.
Carbon cycle
Types of Biomass Resources
Corn Sugarcane
Napier grassLignocellulosic waste Algae
Sugar CropsIncludes sugarcane, sugar beets, sweet
sorghum, apples, grapes etc.Molasses – residual syrup remaining from
crystallization of sugar from sugarcane and sugarbeets, is also a common feedstock
Pulp and papermill sludges contain 40-50 wt% glucose
These sugars can be directly fermented by yeast Saccharomyces cerevisiae .
SugarcaneBrazil is the largest producer (514 million
tons in 2007)India is the second largest producer, followed
by China.It has stalks bunched in stools of 5-50 stalksCan be grown in regular rotation with other
crops.Requires tropical or subtropical climate.Time to maturity is between 8-24 months.Strong sunlight and plentiful water is needed
to meet the considerable growth potential.
Sugar BeetA biennial root vegetableHigh content of sucrose in its root.Grown in temperate climatesAverage sugar (sucrose) content is around
17% of total raw biomass.World’s largest sugar beet producer: France,
USA and Russia
Sweet SorghumUsed in the production of sugar, syrup, fuel
and roofing applications.Thrive under drier and warmer conditions.Largely produced in Asia, followed by North
America.The juice contains 56% sucrose, 30% glucose,
14% fructose.
Starch and Inulin CropsCorn, potatoes, cassava etc. Starch is a glucose polymer with 2 main
components: amylose and amylopectinInulin, like starch, is a storage carbohydrate,
but its basic unit is fructose rather than glucose
Inulin is commonly found in tuber crops such as dahlia and Jerusalem artichoke.
CornTypically planted in the spring when warm
temperatures are condusive for growth.Soil moisture is another key factor that
determines the adaptability of corn to an area.
Predominant component of corn is starch, 64-78% of the total mass on a dry basis.
Other carbohydrates include cellulose fiber, pentosans, sucrose and monomeric sugars such as glucose, fructose and raffinose.
WheatChina – largest producer, followed by IndiaContains 77% starch content (dry basis)
Agricultural ResiduesIt refers to either crop residues or processing
residues.Corn stover – remains in a field after
harvesting corn, includes stalks (50%), leaves (22%), cobs (15%) and husks (13%).
Wheat straw Rice straw
Herbaceous BiomassSwitchgrass MiscanthusCoastal Bermuda Grass
Oil SeedsSoybeanRapeseed (Canola)SunflowerOil PalmWaste Edible Oil
Biofuel CharacteristicsBiofuel – a solid, gaseous or liquid fuel
produced from biomassEthanol, butanol, diesel etc.1st generation biofuel – food based material 2nd generation biofuel – cellulosic materials3rd generation biofuel - algae
Comparison of Transportation FuelsFossil Fuel - derived
Biorenewable Resource - Derived
Fuel Type Gasoline No 2 Diesel Fuel
Methanol Ethanol Methyl ester (from soybean)
Specific gravity @ 16C
0.72 – 0.78
0.85 0.796 0.794 0.886
Kinematic viscosity @ 20C (m/s)
0.8 x 10-6
2.5 x 10-
6
0.75 x 10-6
151 x 10-6
3.9 x 10-6
Boiling point (C) 30-225 210-235 65 78 339
Flash point (C) -43 52 11 13 188
Autoignition temp (C)
370 254 464 423 -
Octane no. (research)
91-100 - 109 109 -
Octane no. (motor) 82-92 - 89 90 -
Cetane no. < 15 37-56 < 15 < 15 55
Heat of vaporization (kJ/kg)
380 375 1185 920
Lower heating value (MJ/kg)
43.5 45 20.1 27 37Source: Brown, R.C. (2003) Biorenewable Resources
Bioethanol Global Demand