Is diesel fuel straight petroleum or have they been putting "up to ten percent ethanol" in it?
Ethanol in diesel?
- Thread starter mjoekingz28
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"Miscible".......What a wonderful word. And so seldom called for, in conversation.
ethanol kills a common rail pump in short order. Don't put gas in a modern diesel even to lower the pour point (or make sure it's ethanol free, but still advise against it)
Originally Posted By: 4wheeldog
"Miscible".......What a wonderful word. And so seldom called for, in conversation.
It's a well known term in motor oil. Not unusual to hear it around here.
"Miscible".......What a wonderful word. And so seldom called for, in conversation.
It's a well known term in motor oil. Not unusual to hear it around here.
Originally Posted By: mjoekingz28
Is diesel fuel straight petroleum or have they been putting "up to ten percent ethanol" in it?
I don't believe that ethanol is suitable for traditional diesel. I works with modern gasoline engines. However, there has been talk of making a diesel/ethanol blend using suitable solvents that allow both to properly mix. The following mentions that ethanol phase separates in diesel at lower temperatures.
http://web.mit.edu/nuwong/Public/Diesohol/Lapuerta_Stability of Ethanol-Diesel blends.pdf
Water is of course an issue with gasoline. An alcohol will generally prevent this from being an issue since it mixes with both water and gasoline. I think the issue with diesel and alcohol is adding something that enables the two to mix.
Is diesel fuel straight petroleum or have they been putting "up to ten percent ethanol" in it?
I don't believe that ethanol is suitable for traditional diesel. I works with modern gasoline engines. However, there has been talk of making a diesel/ethanol blend using suitable solvents that allow both to properly mix. The following mentions that ethanol phase separates in diesel at lower temperatures.
http://web.mit.edu/nuwong/Public/Diesohol/Lapuerta_Stability of Ethanol-Diesel blends.pdf
Water is of course an issue with gasoline. An alcohol will generally prevent this from being an issue since it mixes with both water and gasoline. I think the issue with diesel and alcohol is adding something that enables the two to mix.
They've been trying to get it into diesel for longer than I've been an engineer (over 1/4 century it was a subject of discussion).
Biodiesel is the current way of getting biofuels into the diesel market, and is much more acceptable...biodiesel starts with an alcohol too, I've made it with ethanol (and E85).
Biodiesel is the current way of getting biofuels into the diesel market, and is much more acceptable...biodiesel starts with an alcohol too, I've made it with ethanol (and E85).
My final year project in engineering school was on supplementing diesel fuel with methanol, and that was 36 years ago. I installed a carburetor on the intake manifold to introduce the methanol and backed off the diesel injection, leaving just enough to ignite the methanol. It worked at low proportions of methanol but seemed to have no practical potential for more as it knocked badly.
JW LJ!
Thanks Shannow.....so we use corn whiskey in gasoline and corn oil in diesel????
Thanks Shannow.....so we use corn whiskey in gasoline and corn oil in diesel????
Originally Posted By: Kiwi_ME
My final year project in engineering school was on supplementing diesel fuel with methanol, and that was 36 years ago. I installed a carburetor on the intake manifold to introduce the methanol and backed off the diesel injection, leaving just enough to ignite the methanol. It worked at low proportions of methanol but seemed to have no practical potential for more as it knocked badly.
Great info.
(former??) member here oilyriser mentioned on a number of times a vaporised ethanol process (like an LPG converter ??) very lean into a diesel intake, and able to take the typical distilled ethanol with it's inherent moisture.
There's a mob in Oz that can provide a lean injection process to use petrol, E10, E85 injected into diesel's intakes.
My final year project in engineering school was on supplementing diesel fuel with methanol, and that was 36 years ago. I installed a carburetor on the intake manifold to introduce the methanol and backed off the diesel injection, leaving just enough to ignite the methanol. It worked at low proportions of methanol but seemed to have no practical potential for more as it knocked badly.
Great info.
(former??) member here oilyriser mentioned on a number of times a vaporised ethanol process (like an LPG converter ??) very lean into a diesel intake, and able to take the typical distilled ethanol with it's inherent moisture.
There's a mob in Oz that can provide a lean injection process to use petrol, E10, E85 injected into diesel's intakes.
what do you mean by a lean injection process?
ethanol/methanol injection in the intake of diesels is nothing new, but running the stuff through the diesel injection equipment is a different matter.
ethanol/methanol injection in the intake of diesels is nothing new, but running the stuff through the diesel injection equipment is a different matter.
Interesting that this is coming up now.
I've recently been doing some research into this topic and found this little article on E-Diesel (ethanol enriched diesel) not to be confused with biodiesel
https://www.dieselnet.com/tech/fuel_ediesel.php
I'd love to hear your thoughts.
I've recently been doing some research into this topic and found this little article on E-Diesel (ethanol enriched diesel) not to be confused with biodiesel
https://www.dieselnet.com/tech/fuel_ediesel.php
I'd love to hear your thoughts.
Solarent,
the article is (expensive) subscription only, so going off the headings, they are pretty much what our uni discussions were.
Shifting pollutants from one group to the other.
Stability of the "emulsion", deleterious effects if it's not stable, how they mix with regular fuels, and corrosion and wear issues in injection equipment.
the article is (expensive) subscription only, so going off the headings, they are pretty much what our uni discussions were.
Shifting pollutants from one group to the other.
Stability of the "emulsion", deleterious effects if it's not stable, how they mix with regular fuels, and corrosion and wear issues in injection equipment.
Originally Posted By: Shannow
Solarent,
the article is (expensive) subscription only, so going off the headings, they are pretty much what our uni discussions were.
Shifting pollutants from one group to the other.
Stability of the "emulsion", deleterious effects if it's not stable, how they mix with regular fuels, and corrosion and wear issues in injection equipment.
Sorry about that. I didn't realize my work computer pulled an auto-login to the site using the company subscription....
Quote:
Properties & Engine Performance
Overview
Relative to diesel, e-diesel blends without additives are typically characterized by poor stability, low flash point, high volatility, low cetane and low lubricity. Cold flow properties tend to improve even though cloud point can be significantly higher (see discussion below). E-diesel additive packages are designed to improve the blend stability, cetane number and the lubricity in the final blended product. Low flash point and high volatility persist. The exact properties depend on the ethanol content and on the additive.
Ignition Quality & Combustion
The cetane number of neat ethanol is low. Estimates put it at between 5-15. Blending ethanol into diesel fuel will reduce the cetane number because ethanol is a short chain molecule that is more resistant to free-radical scission than longer molecules, alcohol functional groups tend to generate lower cetane numbers, and ethanol has a high enthalpy of vaporization with an associated evaporative cooling that tends to cool the entire fuel charge during injection. The low cetane results in long ignition delays and unacceptable deterioration in combustion quality. In order to offset the lower cetane number of ethanol, additive packages for e-diesel contain cetane improver additives. If sufficient cetane improver is in the additive package, the cetane number of the final e-diesel blend can be restored to that of the baseline diesel fuel or in some cases, be even higher.
Safety
Ethanol has a flashpoint of about 17°C while that of diesel fuel, depending on grade and the jurisdiction, is 38°C and higher. Blends of 10-20% ethanol with diesel have flashpoints almost identical to that of neat ethanol. Adding ethanol to diesel makes the resulting blend a Class I liquid (flashpoint < 37.8°C) according to the US National Fire Protection Agency (NFPA) ratings. Diesel fuel is a Class II liquid. Class I liquids have more stringent storage requirements including more distant location of storage tanks from property lines, buildings, other tanks, and vent terminals, as well as the requirement of flame arrestors on all vents. This means that e-diesel must be stored and handled like gasoline. Considerable end user education in the industry would be required to ensure that the product is properly transported, stored, dispensed, and used. The need for distributors and end users to make modifications to storage tanks and fuel handling equipment will also have significant cost. For this reason, e-diesel is usually only considered a fuel appropriate for fleet use rather than general commercial sale.
Based on flammability limits and vapor pressure data for ethanol, flammable mixtures of ethanol and air in a closed container such as a fuel tank can easily form at temperatures of approximately 10°C - 40°C (The flammable temperature range at equilibrium in a closed container for diesel is approximately 64°C to 150°C, and for gasoline is approximately -40°C to -17°C). Although ignition of the gasoline can easily occur at the mouth of the fill neck, it is virtually impossible for ignition to propagate down the fill pipe and into the fuel tank, since the fuel/air mixture is too rich. With e-diesel, however, ignition could easily propagate down a fill neck and into the fuel tank at typical ambient temperatures, causing the fuel tank to catastrophically fail. The low flash point and vehicle tank vapor flammability have been identified as the most important technical barriers to commercialization of e-diesel. Flame arrestors are therefore critical safety devices for the fill necks of fuel tanks for e-diesel [Weyandt 2003].
The following actions have been reccomended to reduce safety risks from the use of e-diesel [Waterland 2003]:
Equipping all fuel storage tank vents and the vehicle tank vent and fill openings with flame arresters designed for use with ethanol,
Ensuring that all fuel transfer processes including vehicle fueling incorporate effective vapor recovery systems,
Establishing an electrical ground connection between the vehicle and the fueling station fuel dispenser,
Insuring that vehicle fuel tank level detectors are of an intrinsically safe design.
Lubricity
Lubricity and wear are concerns with e-diesel and use of additives is critical to ensure proper lubricity. Tests with a Bosch rotary pump rig have shown that low levels of low acid lubricity improvers can provide adequate protection of fuel injection equipment with e-diesel blends. Common bench tests for fuel lubricity such as ASTM D 6078 and ASTM D 6979 do not accurately predict lubricity performance. While e-diesel blends, even those without lubricity additives, can pass the bench tests, they may not pass pump rig test [Corkwell 2002]. The pump rig test is a much better predictor of actual field performance.
Surfactants used to ensure blend stability of micro-emulsions can also enhance fuel lubricity. Figure 2 shows two cam plates from a distributor type diesel injection pump. The cam plate on the left—showing signs of wear—was operated with e-diesel blend with no additive and poor lubricity. The one on the right was operated using an e-diesel blend with additive that provided good lubricity.
[photo]
Figure 2. Effect of E-Diesel Lubricity on Fuel Injection Equipment
A: Poor lubricity (no additive); B: Good lubricity
(Source: Lubrizol)
Cold Flow Properties
Ethanol has a very low freezing temperature so it is expected to improve cold-flow properties when blended with diesel fuel. While very significant depressions in pour point have been observed with e-diesel blends, the cloud point can actually increase significantly (see Table 1). It is believed that upon cooling, the micelles in e-diesel micro-emulsions grow in size to the point that they become visible and make the fuel cloudy. These ethanol micelles are liquid and will apparently flow through a fuel filter. This is in contrast to the cloud point of a conventional diesel, which indicates the onset of formation of solid wax crystals that can plug a fuel filter [McCormick 2001].
It has been suggested that blending ethanol with biodiesel/diesel fuel blends may improve the cold flow properties of B20 blends. It is reported that B20 prepared from a 50:50 mixture of biodiesel and ethanol rather than 100% biodiesel can provide low temperature flow properties comparable to those of the blending diesel [McCormick 2001].
Operational Issues
Operational problems that have been reported with e-diesel are most commonly related to two properties: the high volatility and low viscosity of e-diesel blends.
Power losses have been reported as a result of fuel boiling when e-diesel blends were used in a 12.5 liter engine with unit injectors after the engine warmed-up [Merrit 2005]. The fuel is routed through the head on this engine design and a portion of the unused fuel is re-circulated through the head, rather than being returned to the fuel tank. It is likely that the fuel became too hot and began to boil while passing through the head. The problem was solved by installing a small cooler to reduce the fuel temperature prior to reaching the injectors. The temperature to which the fuel was cooled was not reported.
In some fuel injection systems, the high volatility of e-diesel may lead to cavitation, resulting in damage to fuel injectors, the injection pump and/or the transfer pump. Transfer pump cavitation can be addressed by moving the pump from the engine to a cooler location such as the fuel tank. Injection pump cavitation could be addressed with a restrictor in the fuel return line [Waterland 2003]. The cavitation issue may be especially significant in engines with advanced fuel systems which produce increased fuel temperatures. The effect of e-diesel on injection equipment must be therefore tested before wider deployment on each type/model of the diesel engine.
The lower viscosity of e-diesel can increase pump and injector leakage resulting in reduced maximum fuel delivery and lower peak power. Hot restart problems may be encountered as well due to insufficient fuel being injected at cranking speed [Hansen 2005].
As it is the case with any fuel additive based technology, the e-diesel additive package may contribute to fuel injector fouling. Considering the high additive content in e-diesel, up to about 5%, the quality of the additive package is of critical importance
Quote:
Emissions
E-Diesel can produce reductions in some regulated emissions. Particulate matter emission reductions up to 30% and higher have been reported. Results with CO, HC and NOx tend to be mixed.
Corkwell and colleagues reviewed exhaust emissions data from a number of different studies [Corkwell 2003]. While the emissions of e-diesel relative to diesel fuel varied widely, they were able to draw several conclusions. When cetane number was a variable, increasing the cetane number of the e-diesel blend to match the diesel fuel, generally resulted in an improvement in emissions of the e-diesel blend with the cetane improver over the e-diesel blend without a cetane improver. On average, regardless of cetane number, e-diesel resulted in an increase in HC and CO emissions, no change in NOx and a reduction in PM. When a cetane improver is used in the e-diesel blend to match the cetane number to that of the diesel fuel, a 6% increase in HC, 9% decrease in CO, 2% reduction in NOx and a 25% reduction is PM was noted. Only modest increases (4% to 7%) in total carbonyls were noted. The impact of e-diesel on regulated emissions noted by Corkwell is summarized in Table 2 (negative percentages indicate emission reduction relative to diesel, positive an emission increase).
Code:
Table 2
Summary of E-Diesel Effect on Emissions
HC CO NOx PM
All data
Average 41% 16% 1% -13%
Minimum -16% -30% -20% -72%
Maximum 164% 93% 25% 65%
Equal cetane number data
Average 6% -9% -2% -25%
Minimum -16% -30% -20% -31%
Maximum 22% 5% 25% -20%
Quote:
Regulated and unregulated emissions were measured from 3 different John Deere Tier II compliant nonroad engines at 3 different blend levels of ethanol and using three different additive packages [Merrit 2005]. The engines included a 6.8 liter model equipped with a rotary injection pump, an 8.1 liter engine equipped high pressure common rail and a 12.5 liter engine with electronic unit injectors. Cetane number of the base diesel fuel was 47.4. That of the blends ranged between 46.6 and 49.9. Increasing ethanol concentration in the fuel led to higher emissions of acetaldehyde (increases ranging from 27% to 139%) and ethanol (from trace levels to levels as high as 52 mg/hp-hr). Smoke and particulate matter emissions decreased with increasing ethanol concentration. PM emissions decreased from 13% to 30%. Except on the 6.8-L engine, CO emissions decreased, by as much as 15%. For the 6.8-L engine, CO increased by as much as 22.6%. NOx emissions were reduced with ethanol use on the 6.8-L and 12.5-L engines, with reductions ranging from 5% to 9%. Emissions of NOx increased by as much as 2% on the 8.1-L engine.
Solarent,
the article is (expensive) subscription only, so going off the headings, they are pretty much what our uni discussions were.
Shifting pollutants from one group to the other.
Stability of the "emulsion", deleterious effects if it's not stable, how they mix with regular fuels, and corrosion and wear issues in injection equipment.
Sorry about that. I didn't realize my work computer pulled an auto-login to the site using the company subscription....
Quote:
Properties & Engine Performance
Overview
Relative to diesel, e-diesel blends without additives are typically characterized by poor stability, low flash point, high volatility, low cetane and low lubricity. Cold flow properties tend to improve even though cloud point can be significantly higher (see discussion below). E-diesel additive packages are designed to improve the blend stability, cetane number and the lubricity in the final blended product. Low flash point and high volatility persist. The exact properties depend on the ethanol content and on the additive.
Ignition Quality & Combustion
The cetane number of neat ethanol is low. Estimates put it at between 5-15. Blending ethanol into diesel fuel will reduce the cetane number because ethanol is a short chain molecule that is more resistant to free-radical scission than longer molecules, alcohol functional groups tend to generate lower cetane numbers, and ethanol has a high enthalpy of vaporization with an associated evaporative cooling that tends to cool the entire fuel charge during injection. The low cetane results in long ignition delays and unacceptable deterioration in combustion quality. In order to offset the lower cetane number of ethanol, additive packages for e-diesel contain cetane improver additives. If sufficient cetane improver is in the additive package, the cetane number of the final e-diesel blend can be restored to that of the baseline diesel fuel or in some cases, be even higher.
Safety
Ethanol has a flashpoint of about 17°C while that of diesel fuel, depending on grade and the jurisdiction, is 38°C and higher. Blends of 10-20% ethanol with diesel have flashpoints almost identical to that of neat ethanol. Adding ethanol to diesel makes the resulting blend a Class I liquid (flashpoint < 37.8°C) according to the US National Fire Protection Agency (NFPA) ratings. Diesel fuel is a Class II liquid. Class I liquids have more stringent storage requirements including more distant location of storage tanks from property lines, buildings, other tanks, and vent terminals, as well as the requirement of flame arrestors on all vents. This means that e-diesel must be stored and handled like gasoline. Considerable end user education in the industry would be required to ensure that the product is properly transported, stored, dispensed, and used. The need for distributors and end users to make modifications to storage tanks and fuel handling equipment will also have significant cost. For this reason, e-diesel is usually only considered a fuel appropriate for fleet use rather than general commercial sale.
Based on flammability limits and vapor pressure data for ethanol, flammable mixtures of ethanol and air in a closed container such as a fuel tank can easily form at temperatures of approximately 10°C - 40°C (The flammable temperature range at equilibrium in a closed container for diesel is approximately 64°C to 150°C, and for gasoline is approximately -40°C to -17°C). Although ignition of the gasoline can easily occur at the mouth of the fill neck, it is virtually impossible for ignition to propagate down the fill pipe and into the fuel tank, since the fuel/air mixture is too rich. With e-diesel, however, ignition could easily propagate down a fill neck and into the fuel tank at typical ambient temperatures, causing the fuel tank to catastrophically fail. The low flash point and vehicle tank vapor flammability have been identified as the most important technical barriers to commercialization of e-diesel. Flame arrestors are therefore critical safety devices for the fill necks of fuel tanks for e-diesel [Weyandt 2003].
The following actions have been reccomended to reduce safety risks from the use of e-diesel [Waterland 2003]:
Equipping all fuel storage tank vents and the vehicle tank vent and fill openings with flame arresters designed for use with ethanol,
Ensuring that all fuel transfer processes including vehicle fueling incorporate effective vapor recovery systems,
Establishing an electrical ground connection between the vehicle and the fueling station fuel dispenser,
Insuring that vehicle fuel tank level detectors are of an intrinsically safe design.
Lubricity
Lubricity and wear are concerns with e-diesel and use of additives is critical to ensure proper lubricity. Tests with a Bosch rotary pump rig have shown that low levels of low acid lubricity improvers can provide adequate protection of fuel injection equipment with e-diesel blends. Common bench tests for fuel lubricity such as ASTM D 6078 and ASTM D 6979 do not accurately predict lubricity performance. While e-diesel blends, even those without lubricity additives, can pass the bench tests, they may not pass pump rig test [Corkwell 2002]. The pump rig test is a much better predictor of actual field performance.
Surfactants used to ensure blend stability of micro-emulsions can also enhance fuel lubricity. Figure 2 shows two cam plates from a distributor type diesel injection pump. The cam plate on the left—showing signs of wear—was operated with e-diesel blend with no additive and poor lubricity. The one on the right was operated using an e-diesel blend with additive that provided good lubricity.
[photo]
Figure 2. Effect of E-Diesel Lubricity on Fuel Injection Equipment
A: Poor lubricity (no additive); B: Good lubricity
(Source: Lubrizol)
Cold Flow Properties
Ethanol has a very low freezing temperature so it is expected to improve cold-flow properties when blended with diesel fuel. While very significant depressions in pour point have been observed with e-diesel blends, the cloud point can actually increase significantly (see Table 1). It is believed that upon cooling, the micelles in e-diesel micro-emulsions grow in size to the point that they become visible and make the fuel cloudy. These ethanol micelles are liquid and will apparently flow through a fuel filter. This is in contrast to the cloud point of a conventional diesel, which indicates the onset of formation of solid wax crystals that can plug a fuel filter [McCormick 2001].
It has been suggested that blending ethanol with biodiesel/diesel fuel blends may improve the cold flow properties of B20 blends. It is reported that B20 prepared from a 50:50 mixture of biodiesel and ethanol rather than 100% biodiesel can provide low temperature flow properties comparable to those of the blending diesel [McCormick 2001].
Operational Issues
Operational problems that have been reported with e-diesel are most commonly related to two properties: the high volatility and low viscosity of e-diesel blends.
Power losses have been reported as a result of fuel boiling when e-diesel blends were used in a 12.5 liter engine with unit injectors after the engine warmed-up [Merrit 2005]. The fuel is routed through the head on this engine design and a portion of the unused fuel is re-circulated through the head, rather than being returned to the fuel tank. It is likely that the fuel became too hot and began to boil while passing through the head. The problem was solved by installing a small cooler to reduce the fuel temperature prior to reaching the injectors. The temperature to which the fuel was cooled was not reported.
In some fuel injection systems, the high volatility of e-diesel may lead to cavitation, resulting in damage to fuel injectors, the injection pump and/or the transfer pump. Transfer pump cavitation can be addressed by moving the pump from the engine to a cooler location such as the fuel tank. Injection pump cavitation could be addressed with a restrictor in the fuel return line [Waterland 2003]. The cavitation issue may be especially significant in engines with advanced fuel systems which produce increased fuel temperatures. The effect of e-diesel on injection equipment must be therefore tested before wider deployment on each type/model of the diesel engine.
The lower viscosity of e-diesel can increase pump and injector leakage resulting in reduced maximum fuel delivery and lower peak power. Hot restart problems may be encountered as well due to insufficient fuel being injected at cranking speed [Hansen 2005].
As it is the case with any fuel additive based technology, the e-diesel additive package may contribute to fuel injector fouling. Considering the high additive content in e-diesel, up to about 5%, the quality of the additive package is of critical importance
Quote:
Emissions
E-Diesel can produce reductions in some regulated emissions. Particulate matter emission reductions up to 30% and higher have been reported. Results with CO, HC and NOx tend to be mixed.
Corkwell and colleagues reviewed exhaust emissions data from a number of different studies [Corkwell 2003]. While the emissions of e-diesel relative to diesel fuel varied widely, they were able to draw several conclusions. When cetane number was a variable, increasing the cetane number of the e-diesel blend to match the diesel fuel, generally resulted in an improvement in emissions of the e-diesel blend with the cetane improver over the e-diesel blend without a cetane improver. On average, regardless of cetane number, e-diesel resulted in an increase in HC and CO emissions, no change in NOx and a reduction in PM. When a cetane improver is used in the e-diesel blend to match the cetane number to that of the diesel fuel, a 6% increase in HC, 9% decrease in CO, 2% reduction in NOx and a 25% reduction is PM was noted. Only modest increases (4% to 7%) in total carbonyls were noted. The impact of e-diesel on regulated emissions noted by Corkwell is summarized in Table 2 (negative percentages indicate emission reduction relative to diesel, positive an emission increase).
Code:
Table 2
Summary of E-Diesel Effect on Emissions
HC CO NOx PM
All data
Average 41% 16% 1% -13%
Minimum -16% -30% -20% -72%
Maximum 164% 93% 25% 65%
Equal cetane number data
Average 6% -9% -2% -25%
Minimum -16% -30% -20% -31%
Maximum 22% 5% 25% -20%
Quote:
Regulated and unregulated emissions were measured from 3 different John Deere Tier II compliant nonroad engines at 3 different blend levels of ethanol and using three different additive packages [Merrit 2005]. The engines included a 6.8 liter model equipped with a rotary injection pump, an 8.1 liter engine equipped high pressure common rail and a 12.5 liter engine with electronic unit injectors. Cetane number of the base diesel fuel was 47.4. That of the blends ranged between 46.6 and 49.9. Increasing ethanol concentration in the fuel led to higher emissions of acetaldehyde (increases ranging from 27% to 139%) and ethanol (from trace levels to levels as high as 52 mg/hp-hr). Smoke and particulate matter emissions decreased with increasing ethanol concentration. PM emissions decreased from 13% to 30%. Except on the 6.8-L engine, CO emissions decreased, by as much as 15%. For the 6.8-L engine, CO increased by as much as 22.6%. NOx emissions were reduced with ethanol use on the 6.8-L and 12.5-L engines, with reductions ranging from 5% to 9%. Emissions of NOx increased by as much as 2% on the 8.1-L engine.
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