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Lecture on BioDiesel
BIO-DIESEL
Biodiesel is a domestically produced, renewable fuel that can be manufactured from vegetable oils, animal fats, or recycled restaurant oils.
Biodiesel is safe, biodegradable, and reduces serious air pollutants such as particulate, carbon monoxide, hydrocarbons, and air toxins.
Blends of 20% bio-diesel with 80% petroleum diesel (B20) can generally be used in diesel engines without any modifications in the engine.
Biodiesel can also be used in its pure form (B100), but it may require certain engine modifications to avoid maintenance and performance problems.
The use of bio-diesel decreases the solid carbon fraction of particulate matter (since the oxygen in bio-diesel enables more complete combustion to CO2)
It reduces the sulfate fraction (bio-diesel contains less than 24 ppm sulfur)
PROPERTIES
Specific gravity : 0.87 to 0.89
Kinematic viscosity @ 40°C : 3.7 to 5.8
Cetane number : 46 to 70
Higher heating value (btu/lb) : 16,928 to 17,996
Sulfur, wt% : 0.0 to 0.0024
Cloud point °C : -11 to 16
Pour point °C : -15 to 13
Iodine number : 60 to 135
Lower heating value (btu/lb) : 15,700 to 16,735
BENEFITS
Substitute or extender for petroleum diesel.
No need of any special pumps or high pressure equipment for fueling.
No need to buy special vehicles or engines to run on bio-diesel.
100 percent bio diesel reduces carbon dioxide emissions by more than 75 percent compared to petroleum diesel. Using a blend of 20 percent bio-diesel reduces carbon dioxide emissions by 15 percent.
Biodiesel is an oxygenated fuel, so it contributes to a more complete fuel burn and a greatly improved emissions profile. Biodiesel produces fewer particulate, carbon monoxide, greenhouse gases and sulfur dioxide emissions, reducing public health risks.
It will reduce the country's dependence on imported oil.
Its flash point is > 150°C, compared to 77°C for petroleum diesel. Hence, it is safe to handle, store, and transport.
DRAWBACKS
NOx emissions are higher, since bio-diesel tends to increase NOx emissions.
Engine performance (fuel economy, torque, and power) is less than that of diesel by 8% to 15%, because of the lower energy content of the bio-diesel (121,000 Btu compared to 135,000 Btu for diesel fuel).
Since its pour point and cloud point is around -10, it solidifies at that temperature during winter in European and American Countries.
DESCRIPTION
BioDiesel is a manufactured product, slightly yellow in color, oily liquid with a slight aromatic odor and a bitter taste.
USES
It is commonly used as fuel for stationary diesel engines like Pump sets and other agricultural implements and also in Diesel cars.
ASTM D-6751 STANDARD for BIODIESEL
Flash point (closed cup) : 130°C minimum, 150°C average
Water and sediment by volume, max. : 0.050%
Kinematic viscosity at 40°C : 1.9-6.0 mm2/s
Ramsbottom carbon residue, % mass : 0.10
Sulfated ash by mass, max. : 0.020%
Sulfur by mass, max. : 0.05%
Copper strip corrosion : No. 3 max
Cetane number : 47 min.
Carbon residue by mass, max. : 0.050%
Acid number, mg KOH /g : 0.80 max.
Free glycerin : 0.020 % mass
Total glycerine by mass, max. : 0.24%
Phosphorus content % mass : 0.001 max.
Distillation @ 360°C : 90%
RAW MATERIALS
Vegetable Oil: To manufacture one Kilo liter of BioDiesel, non-edible vegetable oil, required is 1,050 liters.
Methyl Alcohol: To manufacture one Kilo liter of BioDiesel, 150 liters of Methyl Alcohol is required.
Caustic Potash: To manufacture of one Kilo liter of BioDiesel, 3.8 kgs of caustic potash is required.
QUALITY of RAW MATERIALS
Jatropha oil should be filtered. It should be free of water and other foreign materials. In case the temperature causes the vegetable oil to gel up or become solid, the material should be liquefied by heating up to 40oC in the reactor tank.
Methanol, MeOH – Anhydrous and at least 98% pure.
Potassium Hydroxide, KOH – At least 85% in purity in flakes, powder or pellets. It is very sensitive to atmospheric moisture and must be stored in air-tight containers.
1 TPD PILOT PLANT
Trans-esterification of vegetable oils with alcohol results in GLYCEROL, and FATTY ACID ALCOHOL ESTERS, commonly known as "BIODIESEL".
The Reaction Vessel is a single stainless steel vessel, pressurized, electrically heated and isolated batch unit, capable of either base, or base / base processes for trans-esterifying vegetable oil.
The plant is skid mounted, self-contained, and can be powered by either 240 or 440 VAC. Compressed air 10 psi must be provided.
The vessel has a 1500 liter capacity; it normally processes 1200 liters of vegetable oil / alcohol mix, delivering on average 1000 liters of Biodiesel and 180 liters of glycerol, per batch, in approximately 18 hours.
PROCESS
Vegetable oil and alcohol are pumped through ball valves and visual level. The alkali catalyst is pre-measured and then added to the alcohol. Proportions can be modified by the operator to suit different feedstock. Operator pre-set temperature and pressure values are kept automatically.
PROCESS DESCRIPTION
The alcohol is pumped into the vessel and mixing starts with vent open. The catalyst is pre-measured first testing the feedstock, and then poured into vessel. Finally the vegetable oil is pumped into, heaters turned on and vent closed. The mixing continues under selected conditions of temperature and pressure during a stated period.
Once finished, the mixture settles under pressure, until stratification of the glycerol and liquid alcohol ester occurs.
The resulting glycerol is first extracted under pressure, and the remaining Biodiesel is pushed through a 5 microns filter before being stored.
SAFETY
Instruments, fail-safe visual and sound alarms are incorporated into the control panel. A pressure relief valve and vent manifold allow outside venting to a service line, complying with both ambient and work safety requirements. Metal bodied, spherical valves, are used throughout.
SPECIFICATIONS for 1,000 Lit per Day PLANT
Size : 1730 x 1360 x 2500 mm
Weight : 1200 kg
1500 Liters total volume
1000 Liters Biodiesel production
180 kg glycerol production
1.5 HP motor centrifugal mixer pump
½ HP motor centrifugal oil pump
9 Kw. Heaters
10 kwh energy consumption per batch
SPECIFICATIONS for 1,000 Lit per Hour PLANT
Steel building (w/o basement) around 600 m2
4 x 40,000 L feedstock tanks
Full equipped test laboratory with mass spectrograph
Plate type main heat exchanger
1 BDM chemicals mixer
4 BD2-D vacuum dryers
4 BD2 pressurized reactors
2 x 10,000 L pressurized settling vessels
1 x 40,000 L glycerol tank
3 x 40,000 L biodiesel tanks
Air compressor 7.5 HP
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