Deibel Bioscience provides accurate instrumental analyses and analytical testing of biodiesel required to meet ASTM D6751 and EN 14214 specifications for legitimate RIN generation. Rely on our fast turnaround to give you competitive advantage with access to technical experts for interpretation of your data.
B100 Biodiesel (100% Biodiesel)
Free and Total Glycerin
For the biodiesel producer, measurement of Free and Total Glycerin is critical. Analysis is performed in accordance with ASTM D6584. Free glycerin (or glycerol as it is sometimes referred) is the major co-product of the biodiesel production process when the transesterification reaction has proceeded to completion or near-completion. Typically glycerin is separated from the methyl (or ethyl) esters. If inadequate separation of glycerin occurs, the free glycerin component will be detected during the D6584 analysis. If the oil is not well-reacted, evidence of triglycerides will be indicated in the analysis. Additionally, detection of diglycerides and monoglycerides suggests an incomplete reaction.
ASTM D6751 Requirement: a maximum for free glycerin of 0.020% mass and a maximum for total glycerin of 0.240% mass. There is a maximum 0.40% mass Monoglyceride requirement to qualify as a Grade No. 1B biodiesel (a Cold Soak Filtration Time of less than 200 seconds as well as passing results for the remaining ASTM D6751 analyses is required for a No. 1B designation)
Flash Point is defined as the lowest temperature at which vapors of a material will ignite upon application of an ignition source. The test is conducted under specific test conditions in accordance with ASTM D93. Determination of the flash point is important for the safe handling, storage, and transportation of liquid fuels. Although biodiesel is generally non-hazardous, inadequate methanol recovery during the biodiesel production process will result in a low flash point.
ASTM D6751 Requirement: minimum 93°C. If the flash point is less than 130°C (but greater than 93°C), then methanol recovery must be demonstrated by headspace gas chromatography in accordance with EN 14110.
The Total Acid Number (TAN) is a sum parameter for all acidic components to indicate the level of free fatty acids (FFA) and process acids present in biodiesel as well as organic acids that may be created over time as the fuel ages and oxidizes. TAN analysis is performed in accordance with ASTM D664 which requires potentiometric determination of the titration endpoint. High acid numbers have been linked to fueling system deposits and corrosion.
ASTM D6751 Requirement: a maximum total acid number of 0.50 mg KOH/g.
A fuel property that is particularly important for the low temperature operability of biodiesel fuel is the cloud point, defined as the temperature at which crystals are observed to precipitate from the fuel. Therefore, it is an index of the lowest temperature of the fuel’s usability for certain applications. Operating at temperatures below the cloud point of a biodiesel fuel can result in fuel filter clogging due to the wax crystals. Cloud point determination is also useful information for blending purposes. Cloud point analysis is performed in accordance with ASTM D2500.
ASTM D6751 Requirement: None. Report Only
Water and Sediment
Water and Sediment is determined in accordance with ASTM D2709. The method requires the use of a centrifuge to separate free water and sediment from the fuel. Free water may be detected visually as a “hazy” appearance if gross contamination is present. Gross water contamination can lead to storage tank corrosion and provides an environment conducive to microbial growth. Water and sediment contamination may also be responsible for filter plugging and poor aerosol nebulization in fuel oil systems. Gross water contamination is more frequently observed during fuel storage rather than fuel production.
ASTM D6751 Requirement: a maximum for water and sediment of 0.050% by volume.
Visual Inspection is a standardized test that supports the requirement that fuel is clear and bright and free of visible particulate matter. Biodiesel fuels with these physical qualities will increase the confidence of distributors and end-users.
ASTM D6751 Requirement: Visually free of water, sediment, and suspended solids
Sulfur content impacts engine wear, creates deposits, and may affect emissions control system performance. The effects vary with operating conditions. The Environmental Protection Agency (EPA) has imposed limits on sulfur emissions for environmental reasons and ultra-low sulfur fuels are preferred. B100 contains low quantities of sulfur. Sulfur is analyzed in accordance with ASTM D5453. Gorge Analytical, LLC is EPA-approved for the analysis of low-sulfur and ultra-low sulfur diesel. Visit our Quality Assurance page for more information.
ASTM D6751 Requirement: a maximum sulfur content of 15ppm for Grade S15 and 500ppm for Grade S500.
The Cold Soak Filtration Test (CSFT) is intended to assess the presence of impurities that may precipitate from fuel above the cloud point and cause filter plugging. The test is designed to accelerate precipitate formation. Short filtration times indicate the absence of substances that are likely to cause filter pugging at temperatures above the cloud point. Generally, B100 with low CSFT results and blends made from the B100 will perform well down to the cloud point. CSFT is performed in accordance with ASTM D7501.
ASTM D6751 Requirement: a maximum filtration time of 360 seconds. There is a maximum filtration time of 200 seconds to qualify as a Grade No. 1B biodiesel (a maximum Monoglyceride content of 0.40% mass as well as passing results for the remaining ASTM D6751 analyses is required for a No. 1B designation).
The content of water in petroleum products plays an important role in predicting quality and performance of the product. If moisture is present, premature corrosion and wear, diminished lubrication, filter plugging, decreased effectiveness of additives, and bacterial growth may ensue. Dissolved (entrained) water, not detectable by the human eye, is measured by ASTM D6304, Coulometric Karl Fischer Determination. This test method is applicable to moisture concentrations as low as 10mg/kg.
ASTM D6751 Requirement: None. However, many distributors require 500ppm or less.
As a fuel oxidizes, it may form organic acids and polymers that may cause fuel system deposits, fuel filter clogging, and fuel system malfunctions. Once auto-oxidation of the fuel begins, there is no way to reverse the effects. Although continued acid formation cannot be stopped, the process may be slowed by the addition of anti-oxidants. Oxidation Stability is performed in accordance with EN 15751.
ASTM D6751 Requirement: a minimum oxidative stability of 3 hours.
Calcium and Magnesium ICP
Calcium and Magnesium may form abrasive solids or be present as soluble metallic soaps. If present as solids, excessive injector, fuel pump, piston, and ring wear may result. Soluble metallic soaps may contribute to filter plugging and engine deposits. High levels of these elements may accumulate in exhaust particulate removal devices and may increase back pressure that may require shorter maintenance intervals. Calcium and Magnesium analysis is performed in accordance with EN 14538.
ASTM D6751 Requirement: a maximum of 5ppm (wt/wt) combined calcium and magnesium content.
Sodium and Potassium ICP
Sodium and Potassium are used as reaction catalysts in the production of biodiesel. If not removed from the finished product, Sodium and Potassium may be present as abrasive solids or soluble metallic soaps. Sodium and Potassium may have the same effects as Calcium and Magnesium. Sodium and Potassium analysis is performed in accordance with EN 14538.
ASTM D6751 Requirement: a maximum of 5ppm (wt/wt) combined sodium and potassium content.
Phosphorus content must be kept as low as possible because of its detrimental effect on catalytic converters. Phosphorus coats the catalyst in the converter and renders it ineffective in treating the exhaust. Phosphorus content is measured by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) in accordance with ASTM D4951.
ASTM D6751 Requirement: a maximum phosphorus content of 0.001% mass (10mg/kg).
Acids and sulfur-containing compounds have the potential to cause corrosion in an engine system. The Copper Strip Corrosion test, performed in accordance with ASTM D130, indicates the potential of the biodiesel to affect copper and brass fuel system parts. Polished copper strips are immersed in the biodiesel sample and placed in a sample tube in a heated bath for several hours. The sample test strip is then compared to a standard test strip to determine the effect of the biodiesel on the copper.
ASTM D6751 Requirement: a maximum copper strip corrosion Number 3.
Kinematic Viscosity is the resistance of a fluid to flow under gravity. The viscosity is important in determining optimum handling, storage, and operational conditions. Fuels with a very low viscosity may cause power failure due to leakage at the injector and injector pump. Kinematic viscosity is determined in accordance with ASTM D445.
ASTM D6751 Requirement: viscosity value from 1.9 to 6.0 mm2/s (cSt).
The biodiesel may contain materials that are in the form of abrasive solids, soluble metallic soaps, and unremoved reaction catalysts. The Sulfated Ash determination indicates gross levels of ash-forming compounds in the biodiesel. The primary ash-forming materials that may be present in biodiesel are calcium, magnesium, sodium, and potassium. Sulfated ash is determined in accordance with ASTM D874.
ASTM D6751 Requirement: a maximum sulfated ash content of 0.020% by mass.
Vacuum distillation in accordance with ASTM D1160 is used to determine the boiling range characteristics of a hydrocarbon sample. The boiling characteristics have an important effect on the performance, storage, and safety of the fuel. Biodiesel is produced from oils with fatty acid chains that are mostly straight-chain hydrocarbons containing 16 to 18 carbons. Because biodiesel is relatively homogenous and not composed of hydrocarbon fractions with various volatility properties, biodiesel is characterized by a boiling point rather than a boiling range distribution (i.e., distillation curve).
ASTM D6751 Requirement: 90% distilled at a maximum temperature of 360˚C, Atmospheric Equivalent Temperature (AET).
Carbon residues contribute to engine deposits. The Micro-Carbon Residue test, performed in accordance with ASTM D4530, provides an estimation of the the carbon-depositing characteristics of the fuel.
ASTM D6751 Requirement: maximum carbon residue of 0.050% by mass.
Methanol is a primary raw material reactant used in the production of biodiesel. Methanol content of biodiesel fuel is an important factor in determining the tendency of the fuel to exhibit flammable characteristics. Additionally, a key quality factor for the alcohol reactant material is water content; methanol is hygroscopic to some degree. Water affects the extent and rate of the esterification reaction. Producers will value methanol purity tests to assure that water content is negligible at the start of production. Additionally, excess alcohol used during the production reaction can be recovered to minimize operating costs and environmental impacts. Evaluating the purity of recovered methanol enables the determination of reuse suitability. Lastly, the evaluation of methanol in a glycerin byproduct enables producers to market this fuel by-product as a commodity rather than manage it as a waste. Methanol content in biodiesel is performed in accordance with EN 14110.
ASTM D6751 Requirement: maximum methanol content of 0.2% mass. If the Flash Point is greater than 130° C, methanol analysis is not required.
Derived Cetane Number
The Derived Cetane Number relates to the readiness of the fuel to self-ignite when exposed to the high temperatures and pressure in the diesel engine combustion chamber. The number is also indicative of the relative fuel stability. On-highway diesel fuels in the U.S. are required to have Cetane numbers of 40 or higher. Derived Cetane Number is evaluated in accordance with ASTM D6890.
ASTM D6751 Requirement: minimum cetane number of 47.
Soap and Catalyst
Production of biodiesel using an alkali catalyst always produces some amount of soap. There will be more soap with recycled restaurant waste and animal fats and less with refined vegetable oils. Catalyst and soap tend to concentrate in the glycerol phase; however, some may be found in the biodiesel phase even after the washing process. Soap and Catalyst are evaluated to determine the presence of residual contaminants. The presence of soap is attributed to saponification of free fatty acids present in the feedstock. Residual catalyst may remain if the reaction is incomplete or may be attributable to the excessive use of initial caustic reagent material.
ASTM D6751 Requirement: None.
We provide accurate instrumental analyses and analytical testing of ethanol and E85 required to meet ASTM D4806 and ASTM D5798 specifications for legitimate RIN generation. Rely on our fast turnaround to give you competitive advantage with access to technical experts for interpretation of your data.
Ethanol and Methanol
Federal regulations require fuel ethanol to be made unfit for human consumption. However, the fuel ethanol must contain a minimum concentration of ethanol and a minimum concentration of other organic oxygen compounds to protect the properties of ethanol/gasoline blends. ASTM D4806 Requirement: a minimum ethanol concentration of 92.1% by volume and a maximum methanol concentration of 0.5% by volume.
The solvent-washed gum content test gravimetrically measures the amount of residue after evaporation of the fuel and subsequent heptane wash. Solvent-washed gum measures gums that are both fuel-soluble and fuel-insoluble. The fuel-insoluble gums can clog fuel filters. Both types of gum can be deposited on surfaces upon evaporation of the fuel. ASTM D4806 Requirement: a maximum solvent-washed gum content of 5.0mg/100mL.
Low molecular weight organic acids such as acetic acid are corrosive to many metals. It is necessary to limit the concentration of these acids in the fuel ethanol to minimize damage to metal engine components. ASTM D4806 Requirement: a maximum acidity of 0.007% mass, as acetic acid.
Specific Gravity (now more commonly called Relative Density) is required for the conversion of measured volumes to volumes at 15 degrees C (the standard temperature). The specific gravity of an ethanol product may be an indicator of contamination. There is no ASTM D4806 requirement for Specific Gravity.
Proof is a measure of the ethanol content and is calculated as 2 times the ethanol concentration by volume. Proofs of denatured ethanol commonly exceed 200 due to the addition of denaturants which have a different density than the ethanol. There is no ASTM D4806 requirement for Proof.
Density is a fundamental physical property. It is a required measurement to convert measurements from mass % to volume % to report values in accordance with ASTM D4806. There is no ASTM D4806 requirement for Density.
The pHe is a measure of the acid strength of a fuel ethanol and is a predictor of the fuel ethanol’s corrosion potential. Low pHe fuel ethanol can cause corrosive wear in fuel injectors and engine cylinders. High pHe fuel ethanol can cause fuel pump plastic parts to fail. ASTM D4806 Requirement: pHe 6.5 – 9.0.
Fuel ethanol must be free of suspended matter and sediment. Turbidity or suspended matter generally indicate major contamination. ASTM D4806 Requirement: the fuel ethanol must be clear and bright at indoor ambient temperatures.
Sulfur contaminates the catalytic converter which is used to reduce environmental pollutants such as hydrocarbons, carbon monoxide, and nitrogen oxides. The Environmental Protection Agency (EPA) has established gasoline sulfur limits in support of vehicle emission standards. ASTM D4806 Requirement: a maximum of 30ppm by mass.
Small quantities of inorganic sulfates can cause deposits in metering devices and plugging in fuel dispensing pump filters. Inorganic sulfates have also been shown to cause fuel injector sticking in automobiles which results in engine misfiring and poor driveability. ASTM D4806 Requirement: a maximum total sulfate concentration of 4ppm by mass.
Chloride ions are corrosive to many metals and may cause premature engine wear. Chloride salts can also cause filter plugging and deposits in fuel injectors. ASTM D4806 Requirement: a maximum of 10ppm by mass.
Copper actively catalyzes low-temperature oxidation of hydrocarbons. If present in concentrations greater than approximately 12 parts per billion (ppb) by mass, significant increases in the rate of gum formation can occur. ASTM D4806 Requirement: a maximum of 0.1ppm by mass.
Water contamination can cause serious operating problems in normal spark-ignition engines. Water contamination is typically encountered during fuel transportation and storage. Additionally, gasoline-ethanol blends tend to absorb moisture from the air. For these reasons, it is important to limit the water concentration of the ethanol intended for blending in order to reduce the risk of phase separation. ASTM D4806 Requirement: a maximum of 1.0% by volume.