Biodiesel
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3.4.17 Phosphorous
The level of phosphorous in biodiesel is measured as per ASTM D 4951 test
method using plasma atomic emissions spectrometry. Phosphorous content in fuel depends upon feedstock. Using emission spectrograph emission
standards of sample compared with reference. Phosphorous can damage
catalytic converters used in emission control systems and causes injector
fouling. Currently, in order to meet the latest emission norms automotive
manufacturers are using catalytic converters and hence it is necessary to
keep low levels of phosphorous in fuel.
3.4.18 Methanol/ethanol Content
Alcohol is the major ingredient in the biodiesel production process. In general, the processor will recover excess methanol by a vacuum stripping process. Any methanol remaining after this process should be removed by a
water washing process. Therefore, the residual alcohol level should be very
low. Even 1% of methanol in biodiesel can lower the flash point from 170 to
40ºC. Thereby, including flash point in the specification, the standards limit
the alcohol to a very low level, less than 0.1%.
Alcohol content in the biodiesel is quantified as per EN 14110 test method.
Sample is heated at 80ºC to allow desorption of contained methanol into the
gas phase. A defined part of the gas phase is injected into GC where methanol is detected with a flame ionization detector. Methanol amount is determined based on the peak observed and with reference to standards. Alcohol
content in the biodiesel accelerates deterioration of rubber seals and gaskets,
damage to fuel pumps and injector, and reduces the flash point.
3.4.19 Lubricity
Excessive wear due to lower lubricity shorten the life of fuel pumps and
injectors. The lubricity of fuel depends on the crude source, refining process to reduce the sulfur content, and the type of additives used. The ball on
cylinder lubricity evaluator (BOCLE) and high frequency reciprocating rig
(HFRR) are used to evaluate the lubricity of fuel.
The HFRR method recommends that a limit of 460 micron wear scar
diameter (WSD) for diesel. Lower wear scar diameter is an indication of
better lubricity property of fuel. Even with 2% biodiesel mixed with diesel WSD comes down to 325 micron. Oil companies reduce the sulfur
content to meet the Euro IV/V norms, and loss occurring due to reduction in sulfur level can be compensated by addition of biodiesel in diesel.
Even 2% of biodiesel in diesel is sufficient to address the lubricity-related
problems.
Hu et al. (2005) conducted studies to evaluate the lubricity properties of
biodiesel (refined and unrefined) blended with diesel. Table 3.5 shows the
67
3.4.17 Phosphorous
The level of phosphorous in biodiesel is measured as per ASTM D 4951 test
method using plasma atomic emissions spectrometry. Phosphorous content in fuel depends upon feedstock. Using emission spectrograph emission
standards of sample compared with reference. Phosphorous can damage
catalytic converters used in emission control systems and causes injector
fouling. Currently, in order to meet the latest emission norms automotive
manufacturers are using catalytic converters and hence it is necessary to
keep low levels of phosphorous in fuel.
3.4.18 Methanol/ethanol Content
Alcohol is the major ingredient in the biodiesel production process. In general, the processor will recover excess methanol by a vacuum stripping process. Any methanol remaining after this process should be removed by a
water washing process. Therefore, the residual alcohol level should be very
low. Even 1% of methanol in biodiesel can lower the flash point from 170 to
40ºC. Thereby, including flash point in the specification, the standards limit
the alcohol to a very low level, less than 0.1%.
Alcohol content in the biodiesel is quantified as per EN 14110 test method.
Sample is heated at 80ºC to allow desorption of contained methanol into the
gas phase. A defined part of the gas phase is injected into GC where methanol is detected with a flame ionization detector. Methanol amount is determined based on the peak observed and with reference to standards. Alcohol
content in the biodiesel accelerates deterioration of rubber seals and gaskets,
damage to fuel pumps and injector, and reduces the flash point.
3.4.19 Lubricity
Excessive wear due to lower lubricity shorten the life of fuel pumps and
injectors. The lubricity of fuel depends on the crude source, refining process to reduce the sulfur content, and the type of additives used. The ball on
cylinder lubricity evaluator (BOCLE) and high frequency reciprocating rig
(HFRR) are used to evaluate the lubricity of fuel.
The HFRR method recommends that a limit of 460 micron wear scar
diameter (WSD) for diesel. Lower wear scar diameter is an indication of
better lubricity property of fuel. Even with 2% biodiesel mixed with diesel WSD comes down to 325 micron. Oil companies reduce the sulfur
content to meet the Euro IV/V norms, and loss occurring due to reduction in sulfur level can be compensated by addition of biodiesel in diesel.
Even 2% of biodiesel in diesel is sufficient to address the lubricity-related
problems.
Hu et al. (2005) conducted studies to evaluate the lubricity properties of
biodiesel (refined and unrefined) blended with diesel. Table 3.5 shows the