| NOTICE |
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These recommendations are subject to change without notice. Consult your local Cat dealer for the most up to date recommendations. |
Biodiesel is a renewable fuel that can be made from vegetable oils, animal fat, and waste cooking oil. Soybean oil, rapeseed oil, and palm oil are some of the common vegetable oil sources. The raw oils or animal fats are chemically processed (esterified) to form a fatty acid methyl ester (referred to as FAME). The esterified product (FAME) is biodiesel fuel that can be used in compression ignition engines. Without the chemical processing referred to as esterification, the oils or fats are not suitable for use as fuel in compression ignition engines. The oil or fat must be esterified and the water and contaminants removed.
Fuel made of 100 percent FAME is referred to as B100 biodiesel or neat biodiesel.
Biodiesel can be blended with distillate diesel fuel. The blends can be used as fuel. The most commonly available biodiesel blends are B5, which is 5 percent biodiesel and 95 percent distillate diesel fuel. Also, B20, which is 20 percent biodiesel and 80 percent distillate diesel fuel. The percentages are volume-based.
U.S. distillate diesel fuel specification "ASTM D975" includes up to B5 (5 percent) biodiesel. Any diesel fuel in the U.S. may contain up to B5 biodiesel fuel without labeling that indicates biodiesel content in the finished fuel.
European distillate diesel fuel specification "EN 590" includes up to B5 (5 percent) biodiesel and in some regions up to B7 or B8 (7 or 8 percent by volume) biodiesel. Any diesel fuel in EU may contain up to these blend levels of biodiesel fuel without labeling that indicates biodiesel content in the finished fuel.
Certain regions or countries around the world may mandate blend levels of B20 or higher. Refer to the local regulations and mandates and to local biodiesel specifications for fuel quality.
Biodiesel fuel that is per AVSpare and Industry recommended specifications (Refer to Table 2 in this Chapter) offers the following advantages:
- Renewable fuel, nontoxic, and biodegradable
- Reduces tailpipe particulate matter (PM), hydrocarbon (HC), and carbon monoxide (CO) emissions from most modern diesel engines
- High lubricity, hence reduces friction
- High cetane number
Biodiesel at B5 blend level has the same attributes as diesel fuel. At blend levels over B5, biodiesel has the following attributes that are different than diesel fuel and require management:
- Energy density is lower than diesel fuel. At B100, biodiesel has about 8% lower energy density than diesel fuel. At B20 or lower blend levels, the energy density difference from diesel fuel is not significant.
- Oxidation stability and storage stability are lower than diesel fuel.
- Cold temperature operability is different than diesel fuel. Cloud point pour point and CFPP are typically higher than diesel fuel.
- Materials compatibility is more restricted than diesel fuel.
- A higher tendency to dissolve and absorb water than diesel fuel.
- Metal content is higher than diesel fuel. Biodiesel can contain certain materials naturally or due to processing (phosphorus, sodium, calcium, potassium, and magnesium). The maximum levels of these materials are controlled by the appropriate specifications.
- Contaminants content due to incomplete esterification or purifying process can be present. These contaminants may include glycerides, mono and diesters, sterol glucosides, and others.
- Higher propensity for microbial growth due to the biodegradable nature of biodiesel and to the tendency of higher water absorption.
Meeting specifications as detailed in this Chapter is paramount for biodiesel fuel used in engines, to avoid performance issues and engine downtime.
Refer to guidelines given in this Chapter and to Tables 15 and 17 for the biodiesel fuel requirements, specifications and risks associated with biodiesel.
Note: The user of the engine has the responsibility of using the correct fuel that is recommended by the manufacturer. The fuel must be allowed by the U.S. EPA and other appropriate regulatory agencies.
| NOTICE |
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In North America, the use of biodiesel from "BQ-9000" accredited producers and "BQ-9000" certified marketers is required. Refer to the “Recommendations” section for details. |
| NOTICE |
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Failures that result from the use of any fuel are not AVSpare factory defects. Therefore, the cost of repair would NOT be covered by the AVSpare warranty for materials and/or the warranty for workmanship. |
Recommendations for the Use of Biodiesel in AVSpare Nonroad Engines
AVSpare Biodiesel recommendations per engine model are given in Table 1.
To be acceptable for blending, the biodiesel constituent must meet the requirements that are listed in Table 4, “AVSpare Specification for Biodiesel Fuel”, the latest edition of "ASTM D6751", and/or the latest edition of "EN14214".
Biodiesel blends of up to B5 must meet the requirements for the distillate diesel fuel that are listed in Table 12, “AVSpare Specification for Distillate Diesel Fuel for Nonroad Diesel Engines”, the latest edition of "ASTM D975", and/or the latest edition of "EN 590".
Certain regions or countries may have their own Diesel fuel and B100 specifications. Fuels used in these regions must follow the required specifications.
Biodiesel blends of B6 to B20 must meet the requirements listed in the latest edition of "ASTM D7467" "EN 16709" (B6 to B20) and must be of an API gravity of 30-45.
Where mandated, biodiesel blends of B30 must meet the regional requirements and/or EN 16709 specification for B30 blends.
The distillate diesel fuel acceptable for blending with biodiesel should be the “AVSpare Specification for Distillate Diesel Fuel for Nonroad Diesel Engines” table in the "Distillate Diesel Fuel" section of thisSpecial Publication, the latest edition of "ASTM D975", and/or the latest edition of "EN 590". No. 1-D and No. 2-D are examples of fuels that are acceptable for creating biodiesel fuel. Refer to “Fuel Specifications” Chapter in this Special Publication for details.
For Tier 4 applications in the U.S., the diesel fuel portion of the final blend must meet the requirements of S15 fuels (15 ppm sulfur) designations in the latest edition of "ASTM D975" specification. For Stage IIIB and later applications in EU, the diesel fuel portion of the final blend must meet the requirements for sulfur free (10 ppm sulfur) designation in the latest edition of "EN 590". The final blend must have maximum of 15 ppm sulfur.
In North America, obtain biodiesel from BQ-9000 accredited producers and BQ-9000 certified marketers. Look for the BQ-9000 biodiesel quality accreditation program certification logo that is available to distributors that meet the requirements of BQ-9000. In other areas of the world, the use of biodiesel that is BQ-9000 accredited and certified, or that is accredited and certified by a comparable biodiesel quality body to meet similar biodiesel quality control standards, is required. For more information on the BQ-9000 program, go to:
http://www.BQ-9000.org| Recommendations for Biodiesel Fuel Application in AVSpare Nonroad Engines (1) | ||
|---|---|---|
| Engine Models | Model specific | Biodiesel acceptable blend levels |
| ACERT engines;
C7 through C32; C-9 through C-18; C280 Series; CM20, CM25 and CM32; 3300 Series 3400 Series; 3500 Series and 3600 series |
Engine models with aftertreatment devices and engine models per Stage V Emissions Regulations | Up to B20 |
| Engine models without aftertreatment devices | Up to B20(2)
(For use of higher blend levels up to B100, consult with your Cat dealer) |
|
| Cat engine model C175 | Tier 4, EU Stage IIIB model, EU Stage V (Locomotive) | Up to B7 |
| All other C175 engines | Up to B20(2)
(For use of higher blend levels up to B100, consult with your Cat dealer) |
|
| Cat engine models: 3003 through 3066 | All engine models | Up to B7(3) |
| Cat engine models:
C0.5 through C7.1(Mechanical (PLN) Fuel System) |
C0.5, C0.7, C1.1, C1.5, C1.6, C2.2, C3.3, C4.4 engine models Tier 2 / EU Stage II / China NR2 or earlier Emissions Regulation, without aftertreatment devices. | Up to B7(3) |
| C1.3, C1.8, C2.4, C2.6, C3.3B, C3.4 engine models without aftertreatment devices | Up to B20 | |
| C0.5, C0.7, C1.1, C1.7, <19kW engine models, Stage V Emissions Regulations, without aftertreatment devices | Up to B20 | |
| C0.5, C0.7, C1.1, C1.5, C1.7, C2.2, C3.3, C3.4, C3.6, C4.4, C7.1 engine models Tier 3 / EU Stage IIIA / China NR3 or later Emissions Regulation, without aftertreatment devices | Up to B20(2) | |
| Cat engine models:C1.7 through C7.1(High Pressure Common Rail (HPCR) Fuel System) | C1.7, C2.2, C2.8, C3.4B, C3.6, C4.4, C6.6, C7.1 engine models Tier 4 / EU Stage IV / EU Stage V / China NR4 or later Emissions Regulation, with aftertreatment devices | Up to B20 |
| C2.8, C3.6, C4.4, C6.6, C7.1 engine models Tier 3 / EU Stage IIIA / China NR3 or later Emissions Regulation, without aftertreatment devices | Up to B20(2) | |
| C3.3B, C3.8 engine models with aftertreatment devices | Up to B7(3) | |
| AVS engine models:C4.4, C6.4 and C6.6 Engine Serial Prefix 444, C4E, 666, C6E | C4.4 engines (S/N 44400001-04303) | Up to B7(3) |
| C6.6 engines (S/N CE600001-14623 and S/N 66600001-09015) | Up to B7(3) | |
| C4.4 engines (S/N C4E05524-Up and 44404304 -Up) | Up to B20(2) | |
| C6.4 and certain C6.6 engines (S/N CE614624-Up and 66609016-Up) | Up to B20(2) | |
| (1) | EU Regulations require the biodiesel blends used in Stage V engines operated within the European Union (EU) to contain no more than 8% v/v FAME unless specified otherwise in the engine-specific Operation and Maintenance Manual. B8 can be used where B7 is specified. |
| (2) | Up to B30 where mandated can be used in these engines. |
| (3) | Use of Biodiesel blends above 7% may cause premature wear of the fuel pump and damage to the low-pressure fuel system components as both may contain material incompatible with higher Biodiesel blends. |
| Fuel Recommendations for AVSpare Nonroad Engines | ||
|---|---|---|
| Biodiesel Blend Stock | Final Blend | Distillate Diesel Fuel used for blending |
| Cat biodiesel specification, (1) "ASTM D6751" or "EN14214" | B5 and B7; Cat distillate diesel fuel specification, (2) "ASTM D975" or "EN590" | Cat distillate diesel fuel specification, "ASTM D975" or "EN590" |
| B20: "ASTM D7467" or "EN 16709" and "API" gravity 30-45
B30: “EN16709” and “API gravity 30-45 |
||
| (1) | Refer to Table 4 in the Biodiesel section of this Special Publication. |
| (2) | Refer to “Cat Specification for Distillate Diesel Fuel for On-Highway Engines” in the Fuel section of this Special Publication. |
Note: Do not change any engine settings when using biodiesel fuel. When the use of biodiesel fuel is planned, simply convert to this fuel. Follow the guidelines, recommendations, and quality specifications given in this Chapter to avoid any performance issues or downtime.
Two methods can be used for determining the volume percent biodiesel in a biodiesel blend:
- "ASTM D7371" - "Test Method for Determination of Biodiesel (Fatty Acid Methyl Esters) Content in Diesel Fuel Oil Using Mid Infrared Spectroscopy (FTIR-ATR-PLS Method)"
- "EN 14078" - "Liquid Petroleum Products - Determination of fatty acid methyl esters (FAME) in middle distillates -Infrared spectroscopy method"
For applications running biodiesel or biodiesel blends, if fuel treatments are needed, consult with your fuel supplier or with a reputable provider. :
Impact of Biodiesel on Engine Oil
Biodiesel fuel has higher density and lower volatility than diesel fuels. As a result, during engine operation, biodiesel fuel that dilutes the crankcase oil may not evaporate as effectively as diesel fuels. For this reason, fuel dilution of crankcase oils may be higher when biodiesel blends are used.
Also, biodiesel contains oxygen molecules. These oxygen molecules cannot be differentiated from oil oxidation when using current oil analysis techniques. As a result, biodiesel fuel dilution of the crankcase oil can appear to be higher oxidation of the oil.
When using biodiesel fuel and higher fuel dilution and/or apparent oil oxidation are detected in the crankcase engine oil, consider all the other characteristics of the used oil If these characteristics, such as wear metals, soot, viscosity or others, are per AVSpare guidelines and have not reached condemnation limits, then the oil drain intervals should not be impacted.
To reduce any potential impact of biodiesel fuel dilution on crankcase oil, the use of Cat S·O·S Services oil analysis is strongly recommended when up to B20 (20 percent) and lower biodiesel blends are used, and required when using biodiesel/biodiesel blends that are B20 or above. When requesting oil analysis, be sure to note the level of biodiesel being used (B5, B20, and so on).
Use of Biodiesel fuel in Engines with Aftertreatment Emissions Control Systems
Biodiesel fuels as defined in the current ASTM specifications, may contain phosphorous, alkali and alkaline metals (sodium, potassium, calcium, and magnesium) due to processing techniques or due to the natural contents of the biodiesel feedstock. When present in biodiesel, these metals form ash upon combustion in the engine. The ash accumulates in the aftertreatment systems such as Diesel Particulate Filters (DPF), DOC or other systems. The ash can affect the life and performance of aftertreatment emissions control devices and may cause the need for more frequent ash service intervals. For these reasons, biodiesel fuels that contain ash forming metals, even at the concentration levels defined in the current specifications, are limited to B20 blend levels in the engines with aftertreatment devices.
Local and regional regulations may also restrict the blend levels allowed in engines of certain emissions levels. EU Stage V regulations REQUIRE the biodiesel blends used in engines operated within the European Union (EU) to be ≤ 8 % volume/volume unless specified otherwise in the engine-specific Operation and Maintenance Manual.
Note: Note that some Cat engines that are certified per EU Stage V can use up to B20 biodiesel blends. Refer to engine or machine OMM and to Table 1.
Biodiesel fuels key difference from diesel fuel is the ester chemical group (contains two oxygen atoms) in every biodiesel molecule. Biodiesel may also have double bonds (unsaturation) in the carbon chain that can vary based on the feedstock. Due to the ester chemical group and the unsaturation, the oxidation stability of biodiesel fuels is typically lower than that of diesel fuel. The oxidation stability of biodiesel and biodiesel blends is controlled in ASTM specifications, "D6751" for B100 and "D5467" for B20. Biodiesel fuels that do not conform to these specifications can oxidize quickly during use due to the high temperature and pressure conditions in the engine or during storage and handling practices. Oxidized biodiesel forms acids, gums, high viscosity and deposits, which can plug filters, form deposits, particularly in the fuel injector, and reduce the performance of fuel systems. Use of biodiesel fuels meeting or exceeding the oxidation stability limits is critical to avoid poor performance and downtime of engines.
To avoid the issues associated with oxidized biodiesel fuel, always purchase fuels that conform to or exceed the specifications (refer to Tables 1 and 4 in this Chapter). Also, follow all the guidelines for appropriate storage and handling of this fuel such as avoiding excessive heat and sunlight during storage, exposure to oxygen (air), contact with metals such as copper, lead, tin, zinc, and others. The use of antioxidants can improve the oxidation stability of biodiesel fuel. The antioxidants are most effective when added to new fuels. Consult with your fuel supplier to ensure the quality of the fuel and refer to the details given in this chapter for guidance.
Cat Diesel Fuel System Cleaner (Part number 343-6210), used as needed or on an on-going basis, is most effective at cleaning and preventing the formation of fuel-related deposits.
Refer to the “Cat Diesel Fuel System Cleaner” topics in the “Distillate Diesel Fuel” section in this Special Publication for additional information. Consult your AVSpare dealer for availability of Cat Diesel Fuel System Cleaner. In case a fuel conditioner is needed to improve certain fuel properties, consult with your fuel supplier or with a reputable provider.
Storage tanks used for storing diesel fuel are appropriate for storing biodiesel fuels. Fuel storage tanks need to be cleaned thoroughly before converting to biodiesel/biodiesel blends. Conversion to biodiesel/biodiesel blends can loosen fuel system and fuel storage tank deposits. Loosened deposits result in filter plugging with the loosened deposits. For this reason, the change intervals of bulk tank continuous filtration unit, dispensing point filters, and onboard engine filters should be shortened for an extended period to allow for this cleaning effect. Once the systems are cleaned, the typical filter service intervals can be resumed.
Biodiesel fuel is hygroscopic, which implies that biodiesel tends to absorb and dissolve water at a higher concentration than diesel. All precautions and measures must be taken to ensure that storage tanks are protected from water ingress. Follow all the contamination control measures provided in the "Contamination Control" section of this Special Publication.
Biodiesel storage duration is shorter than diesel due to the chemical nature of biodiesel. Storage duration is dependent on the blend level. Blends up to B20 or B30 (where mandated) can be stored up to 8 months. Testing of biodiesel at 4 months and monthly thereafter is recommended. B100 can be stored for 4 months. Testing at 2 months and monthly thereafter is recommended. Tests should include oxidation stability, acid number, viscosity and sediments. Refer to Table 4 and related guidelines for details.
Note: If switching from biodiesel to distillate fuel, it is recommended to change all fuel filters to avoid filter plugging. Failure to do so can create low fuel pressure.
Information provided in Table 3 refers to biodiesel and biodiesel blends that fully comply with the appropriate specifications as described in the “Biodiesel” section of this Special Publication and to handling and maintenance procedures that follow recommended guidelines.
| Guidelines and Potential Impacts Associated with the Use of Biodiesel and Biodiesel Blends In Cat Engines(1) | ||||
|---|---|---|---|---|
| Risk | B8-B20 | B21-B30 | B31-B100 | |
| 1 | Reduction of oil change interval | No risk | Not noted in Cat engines | Medium |
| 2 | Fuel filters compatibility risk | No risk | Not noted in Cat engines | Medium risk |
| 3 | Loosening of fuel systems deposits upon conversion to biodiesel | More than ULSD | Medium | High |
| 4 | Bulk filtration of biodiesel | ≤4 microns absolute, required | ≤4 microns absolute required | ≤4 microns absolute required |
| 5 | Energy content of biodiesel | Minor loss of 1-2 percent | Minor loss of 1-2 percent | Detectable loss of 5-8 percent |
| 6 | Elastomers compatibility | Not noted in Cat engines with required material | Not noted in Cat engines with required material | Not noted in Cat engines with required material |
| 7 | Risk of hose compatibility | Low risk of softening | Softening may occur | Softening is likely |
| 8 | Low ambient temperature issues for both storage and operation | Gelling can start higher than 0 C | Gelling at increasing temperatures | Gelling at increasing Temperature, -2 to 18 oC |
| 9 | Oxidation stability-Injector deposits | Not noted in Cat engines | Not noted in Cat engines | Increasing risk |
| 10 | Oxidation stability-Duration of storage(2) | 8 months - start testing at 4 months(3) | 8 months - start testing at 4 months(3) | 4 months - start testing at 2 months(3)(4) |
| 11 | Use in engines with limited operational time | Unacceptable(5) | Unacceptable(5) | Unacceptable |
| 12 | Microbial contamination and growth | Increasing. Testing required - treat at trace levels | Increasing. Testing required - treat at trace levels | High. Testing required - treat at trace levels |
| 13 | Need for water removal | Increasing | Increasing | High |
| 14 | Metal incompatibility | High | High | High |
| 15 | Glycerides, total, free, mono, di (if not per spec) | High | High | High |
| (1) | Information provided in this Table refers to biodiesel and biodiesel blends that fully comply with the appropriate specifications as described in this Chapter and per following recommended maintenance procedures. |
| (2) | Testing of biodiesel or biodiesel blend during storage is strongly recommended. Tests should include oxidation, acid number, viscosity and sediments. Tests should be conducted periodically to ensure biodiesel is per specification. Antioxidants are allowed to improve stability. Consult with your fuel supplier for more information. |
| (3) | Testing is recommended at the indicated duration of storage and on a monthly basis thereafter. Tests should include oxidation, acid number, viscosity and sediments. |
| (4) | B100 should be stored at temperatures of 3 degrees C to 6 degrees C (5 degrees F to 10 degrees F) above the cloud point. |
| (5) | If B20 or B30 are used in engines of limited operational time, it is recommended that a stabilizer additive is added at the beginning of the storage period. Follow all storage recommendations. |
The following are details of the Risks and Guidelines listed in Table 3. Refer to the paragraph reference numbers:
- When using biodiesel fuel, dilution of oil by the fuel may increase as detailed in this Chapter. Use S·O·S Services oil analysis to monitor the condition of the engine oil. S·O·S Services oil analysis will also help determine the oil change interval that is optimum. Use of S.O.S is strongly recommended for up to B20 biodiesel blends and required for blends >B20.
- Confirm with the filter manufacturer that the fuel filter/filters to be used are compatible with biodiesel. Fuel water separators are preferred when biodiesel is used.
Note: Cat fuel filters and Cat fuel water separators are compatible with biodiesel fuel.
- Conversion to biodiesel can loosen fuel tanks and fuel system deposits. During the conversion period fuel filter change intervals should be shortened to allow for this cleaning effect. Once the deposits are removed, convert back to the regular filter service intervals. Filter change interval of 50 hours or less should be used during initial conversion to B20 or higher biodiesel blends.
- Filter biodiesel and biodiesel blends through a fuel filter with a rating of 4 microns (c) absolute or less. Filters should be on the device that dispenses the fuel from the bulk storage tank to the fuel tank for the engine. Bulk filtration with fuel water separators is recommended. Series filtration is recommended.
- Neat biodiesel (B100) typically provides less energy per gallon compared to diesel fuels. The energy content of B100 is 5 percent to 8 percent lower than No. 2 diesel fuel. The energy content of B20 (and B30 where mandated) is 1 percent to 2 percent lower than No. 2 diesel fuel, which is not significant. Do NOT attempt to change the engine rating to compensate for the power loss. Any adjustments to the engine in service may result in violation of emissions regulations such as the U.S. EPA anti- tampering provisions. Also, if any tempering with the engine ratings occurs, problems may occur when the engine is converted back to 100 percent distillate diesel fuel.
- Compatibility of the elastomers with biodiesel can be different than compatibility with diesel fuel. Prolonged exposure of certain elastomers, hoses, seals, and gaskets to B100 may cause some degradation and softening of these materials. The condition of gaskets, seals, and hoses should be monitored regularly. The risk of degradation increases with the increase of biodiesel blend level.
- In general, Cat engines built early to mid-90s and beyond use Viton seals and Viton O-rings in the fuel system. Viton is compatible with biodiesel and degradation upon exposure to this fuel is not expected.
- Nitrile hoses typically used in some fuel transfer lines are not compatible with biodiesel. Hoses exposed to biodiesel and biodiesel blends may soften and may show some beading of fluid on the outside of the hose. Monitor the condition of the hoses and confirm with the hose manufacturer that the hoses are compatible with the biodiesel blend used. If necessary, replace with hoses of compatible materials. Consult with Cat dealers for appropriate hose materials.
- Biodiesel fuels may gel or freeze at high temperatures due to the nature of this fuel. Ensure that the biodiesel pour point is appropriate for the climate of the application. In general, the risk of low temperature gelling of biodiesel increases with the increase of blend levels and may depend on the biodiesel feedstock (soy, used cooking oil, animal fats, palm and others). If the pour point of the biodiesel is not appropriate for the climate of the application, the fuel can gel and plug filters, hoses and transfer lines. At low ambient temperatures, biodiesel fuel may need to be stored in a heated building or a heated storage tank. Consult your biodiesel supplier for assistance in the blending and attaining of the proper cloud point for the fuel. Refer to "Modifying the Cloud Point" in the "Diesel Fuel" Section of this Special Publication.
Note: The performance of cold flow improvers may be less effective in biodiesel fuel compared to diesel fuel. Consult the fuel supplier for appropriate cold flow improvers if needed.
- Biodiesel oxidation stability is in general lower than that of diesel fuel, as detailed earlier in this Chapter. The use of biodiesel fuels that are not per specifications can accelerate fuel oxidation in the fuel system. Also, engines with an electronic fuel system operate at higher temperatures and pressures that can also accelerate fuel oxidation. Oxidized fuel can form deposits in fuel injection systems and in fuel systems in general. Always use biodiesel fuel that meets or exceeds the stability limits defined in biodiesel specifications as given in this Chapter to avoid fuel oxidation and degradation. The use of appropriate antioxidants can enhance oxidation stability of biodiesel. Refer to “Biodiesel Fuel Stability” section of this chapter for details and guidelines.
- Due to the chemical nature of biodiesel fuel, biodiesel can age and degrade during long-term storage. Fuel aging and fuel oxidation upon long- term storage may cause the formation of gels, acids and/or deposits. For these reasons, biodiesel should be used within a limited time from production. To ensure appropriate storage duration, testing of the stored biodiesel is recommended. Tests should include oxidation, acid number, viscosity, and sediments. Tests should be conducted at the durations given in Table 4 to ensure that biodiesel is per specification. Antioxidants are recommended to improve stability of biodiesel and increase the storage time limits. Consult with your fuel supplier or with a reputable provider to select appropriate additives.
- B20 and B30 (where mandated) biodiesel blends can generally be stored up to 8 months. Testing of B20 and B30 blends is recommended at 4 months of storage and on a monthly basis thereafter to ensure that the fuel has not degraded.
- B100 biodiesel can generally be stored up to 4 months. Testing of B100 is recommended at 2 months of storage and every two weeks thereafter to ensure that the fuel has not degraded. The use of appropriate additives is required if B100 is stored for more than 4 months. Consult your fuel supplier for more information.
- B100 should be stored at temperatures of 3° C to 6° C (5° F to 10° F) above the cloud point. Other storage conditions such as avoiding direct sunlight or heat should be followed.
- Due to limited oxidation stability and other potential issues, engines with limited operational time and seasonal use should either not use biodiesel/ biodiesel blends or, while accepting some risk, limit biodiesel to a maximum of B5. Examples of applications that should limit the use of biodiesel are the following: Standby Generator sets and certain emergency vehicles, school buses, farm machinery, etc. For more information, refer to the “Seasonal Operation” section.
- For standby generator sets and emergency vehicles that use biodiesel, sample the fuel in the engine tank monthly. Test the fuel for acid number and oxidation stability. If the test results show that the fuel is degraded and not in specification (provided in Table 4 in this “Biodiesel” section), drain the tank, and flush the engine by running with high-quality fuel.
Repeat the process until the system is clean. Refill with high-quality fuel following the recommendations provided in this “Fuel” section. For standby generator sets and emergency vehicles that use biodiesel, use fuel with oxidation stability 10 hours or more per "EN 14112" test method.
- For standby generator sets and emergency vehicles that use biodiesel, sample the fuel in the engine tank monthly. Test the fuel for acid number and oxidation stability. If the test results show that the fuel is degraded and not in specification (provided in Table 4 in this “Biodiesel” section), drain the tank, and flush the engine by running with high-quality fuel.
- Biodiesel is prone to microbial contamination and growth due to the chemical nature. Microbial contamination and growth can cause corrosion in the fuel system and premature plugging of the fuel filter. Consult your supplier of fuel and additive for assistance in selecting appropriate anti-microbial additives. Use anti-microbial additives at the first sign of detection. The cleaning process will be more effective if the biocide is used before extensive growth of microorganisms.
- Biodiesel can absorb and dissolve more water than diesel due to its chemical nature. Care must be taken to prevent water from contaminating the fuel and to remove water from fuel tanks. Water accelerates microbial contamination and growth and can cause system corrosion.
- Biodiesel is not compatible with some metals. Biodiesel, in particular at blends of B20 and higher, will oxidize and form sediments upon long-term contact with lead, zinc, tin, copper, and copper alloys such as brass and bronze. These materials are typically avoided in the fuels systems. Consult your dealer for more information.
- During the esterification and cleaning process of the biodiesel production, glycerol and unreacted oils (mono, di and tri glycerides) may remain in the biodiesel. If these undesirable components are above the allowed specification levels, they can cause issues such as filter plugging and injector deposits. It is critical that the biodiesel fuel is per the recommended specifications.
Note: The use of biodiesel at a B2 level improves the lubricity of the final blend by an estimated 66 percent. Increasing the blend level higher than B2 does not improve the lubricity any further.
Note: Use of biodiesel that is per or preferably exceeds the specifications can avoid the issues listed above and reduce the risks listed above.
Seasonally operated engines should have the fuel systems, including fuel tanks, flushed with conventional diesel fuel before prolonged shutdown periods. Applications that should seasonally flush the fuel system include school buses (U.S.) and farm machinery.
Perform the following process before shutting down the engine for prolonged periods:
- Operate the engine until the fuel level in the tank is low.
- Refill the fuel tank with high-quality conventional distillate diesel fuel.
- Repeat steps 1 and 2 a minimum of two times before the engine is shut down for prolonged periods.
If distillate fuel is not available to operate the engine as described above, while accepting some risk, limit biodiesel to a maximum of B5. The use of biodiesel fuel of high oxidation stability can reduce the risks associated with prolonged storage. Follow the recommendations provided in this section and the guidelines given below to reduce the risk:
- Addition of a high performance diesel fuel oxidation stabilizer is recommended prior to engine shutdown for prolonged periods. The conditioner should be added when the engine is fueled. Preferably, the conditioner is added to the fuel as soon as possible after the fuel production.
- Addition of Cat Diesel Fuel System Cleaner, part number 343-6210, is recommended when the engine is first operated after the prolonged shutdown period and preferably for a total of two tanks of fuel. Follow the recommendations provided in the Cat Diesel Fuel System Cleaner section in the “Fuel” article in this Special Publication.
- For standby generator sets and emergency vehicles that use biodiesel, sample the fuel in the engine tank monthly. Test the fuel for acid number and oxidation stability. If the test results show that the fuel is degraded and not in specification (provided in Table 4 in this “Biodiesel” section), drain the tank, and flush the engine by running with high-quality fuel. Repeat the process until the system is clean. Refill with high-quality fuel following the recommendations provided in this “Fuel” section. For standby generator sets and emergency vehicles that use biodiesel, use fuel with oxidation stability 10 hours or more per “EN 14112” test method.
Consult your AVSpare dealer for the availability of Cat Diesel Fuel System Cleaner. In case a fuel conditioner is needed to improve certain fuel properties, consult with your fuel supplier or with a reputable provider
Biodiesel fuel used for blending must meet the requirements in the following table, the requirements of ASTM "D5761" and/or "EN14214".
The final blend of biodiesel as used in the engine must meet the requirements that are stated in Table 4 this “Biodiesel” article.
B100 intended for blending into diesel fuel that is expected to give satisfactory vehicle performance at fuel temperatures at or below
| Cat Specification for Neat (B100) Biodiesel Blending Fuel | ||||
|---|---|---|---|---|
| Property | Test Method, United States | Test Method, International | Units | Limits, B100 Blending Fuel |
| Density at 15°C | “ASTM D1298” | “ISO 3675” | g/cm3 | 0.86-0.90 |
| Viscosity at 40°C | “ASTM D445” | “ISO 3104” | mm2/s (cSt) | 1.9-6.0 |
| Flash Point | “ASTM D93” | “ISO 3679” | °C | 93 minimum |
| Pour Point | - | - | - | 6 °C (10 °F) minimum below ambient temperature |
| - Summer | “ASTM D97” | “ISO 3016” | °C | |
| - Winter | ||||
| Cloud Point | “ASTM D2500” | °C | Report | |
| Sulfur Content(1) | “ASTM D5453” | “ISO 20846” “ISO 20884” | percent weight | 0.0015(2) maximum |
| Distillation | - | - | - | - |
| T90 | “ASTM D86” | “ISO 3924” | °C | 360 |
| Cetane Number | “ASTM D613” | “ISO 5165” | % evaporation | 45 minimum |
| Sulfated Ash | “ASTM D874” | “ISO 3987” or "ISO 6245" | percent weight | 0.02 maximum |
| Water and Sediment | “ASTM D2709” | “ISO 12937” | percent volume | 0.05 maximum |
| Water | "ASTM D1796" | "EN ISO 12937" | % m/m | - |
| Copper Corrosion, 3 hours at 50oC | “ASTM D130” | “ISO 2160” | - | No. 1 |
| Oxidation Stability | “EN 14112” or "EN 15751" | “EN 14112” or "EN 15751" | hours | 3 minimum |
| Ramsbottom Carbon Residue on 10% bottoms | "ASTM D524" | “ISO 10370” | %-m/m | 0.30 maximum |
| Carbon Residue, Conradson (CCR) | “ASTM D4530” | - | percent weight | 0.05 maximum |
| Esterification | "ASTM D 7806" or "ASTM D 7371" | “EN 14103” | percent volume | 97.5 minimum |
| Total Acid Number | “ASTM D664” | “EN 14104” | mg KOH/g | 0.5 maximum |
| Methanol Content | “EN 14110” | “EN 14110” | percent weight | 0.2 maximum |
| Monoglycerides | “ASTM D6584” | “EN 14105” | percent weight | 0.8 maximum |
| Diglycerides | “ASTM D6584” | “EN 14105” | percent weight | 0.2 maximum |
| Triglycerides | “ASTM D6584” | “EN 14105” | percent weight | 0.2 maximum |
| Free Glycerin | “ASTM D6584” | “EN 14105” | percent weight | 0.02 maximum |
| Total Glycerin | “ASTM D6584” | “EN 14105” | percent weight | 0.240 maximum |
| Phosphorus Content | “ASTM D4951” | “EN 14107” | percent weight | 0.001 maximum |
| Calcium plus Magnesium | “EN 14538” | “EN 14538” | ppm | 5 maximum |
| Sodium plus Potassium | “EN 14538” | “EN 14538” | ppm | 5 maximum |
| Cold Soak Filterability | “ASTM D7501” | – | seconds | 360 maximum |
| Cleanliness | “ASTM D7619” | “ISO 4406” | – | (3) |
| Total contamination | "EN 12662" | "EN 12662" | mg/kg | 24 maximum |
| Appearance | "ASTM D4176" | - | - | Clear and Bright |
| (1) | Methods for testing S are based on the sulfur content in diesel fuel used for blending. Consult with the fuel supplier and ensure the correct method has been used |
| (2) | Sulfur level must be per local regulations. Higher S levels may be used where allowed. |
| (3) | Recommended cleanliness level for fuel as dispensed into the engine fuel tank is ISO 18/16/13 or cleaner per the test methods listed. Refer to the contamination control Chapter for more details. |
Note: Fuels that meet the most current revision level of "ASTM D6751" or "EN 14214" may be used for blending with an acceptable distillate fuel. The conditions, recommendations, and limits that are noted in this Biodiesel section apply.
Refer to the “Reference Material - Fuel” section of this Special Publication for the reference material for the information in this section.