Beta Analytic - Bioethanol Testing - Why Verify Bioethanol

Why Verify Bio-Ethanol

Much of the ethanol produced in the world is actually a petroleum product.

ASTM D6866 protects the interests of investors and bio-mass producers investing in bioethanol production; it is of paramount importance to the success of the domestic bioethanol economy.

ASTM D6866 is the US government approved method for determining the renewable/biobased content of natural range materials, including ethanol additives, bio-diesel additives and biobased products. The method is used routinely by the USDA in the identification of biobased products and is applied without modification for the identification and quantification of bio-ethanol.

Identifying the origin of ethanol serves five significant purposes.

Provides a means to use domestically derived synthetic ethanol to meet quotas and demands rather than imported ethanol.
Protects the interests of bio-mass producers and investors investing in bio-ethanol production.
Provides a means to ensure imported ethanol claimed to be bio-ethanol is correctly and honestly cited.
Deters fraud or otherwise dishonest representation of ethanol as bio-ethanol for the purposes of tax credits.
Provides a single number reference (using ASTM D6866) to be added to accounting requirements associated with the tax credits, distribution, and utilization, and consumption of bio-ethanol.

Ethanol is easily made by the hydrolysis of ethylene, a major petrochemical. Two million tons of petroleum-derived ethanol are produced annually. The principal suppliers are from South Africa and Saudi Arabia, but there are also large plants in the United States, Europe and Japan. Petroleum derived ethanol (synthetic ethanol) is a widely used industrial solvent and has a considerable variety of other applications.

The new tax credits for ethanol in gasoline (Energy Policy Act of 2005 H.R.6) are intended for bioethanol and not petroleum-derived ethanol. The issuance of these tax credits will have to require a certificationthat the ethanol comes from renewable sources. The recognized scientific test is the ASTM (American Society for Testing and Materials) D6866. This unambiguously and quantitatively distinguishes between materials produced from fossil fuels such as petroleum and those produced from contemporary bio-mass.

ASTM D6866 uses the same techniques as radiocarbon dating. Bio-mass consists of contemporary materials containing carbon 14, whereas fossil materials do not have any of this isotope left. It has all decayed away over the years.

Measuring the concentrations of carbon 14 in the ethanol being studied will show whether it had been manufactured from renewable or from fossil materials. It is also anticipated that in some cases there will be a mixture of bioethanol and synthetic ethanol.

Here, ASTM D6866 will quantitatively determine the percentage of bioethanol so that the appropriate tax credit could be given. Likewise, ASTM D6866 would be an applicable test for bulk gasolines containing varying concentrations of bioethanol. The test would indicate the amount of renewable material in the total liquid. However, it must be certain that the gasoline is well mixed so that the very small sample taken is representative of the entire storage tank. This is always an important concern in bulk materials testing.

Radiocarbon dating, first developed in 1947, depends on the continuous production of a radioactive isotope, carbon 14 or radiocarbon, by cosmic rays in the upper atmosphere. The isotope combines with oxygen to form carbon dioxide, which filters down to the biosphere. It is taken up by plants, which are then eaten by animals. The carbon 14 is continuously lost by radioactive decay, but this is balanced by the continuous production by cosmic rays. All living beings, plant and animal, will have the same concentration of carbon 14. However, when the plants or animals die, their carbon 14 is no longer replaced from the atmosphere. The content of this isotope in the dead remains or fossils gradually decreases up to the point where there is essentially none left, taking approximately fifty thousand years.

Radiocarbon dating procedures accurately measure the carbon 14 content in various materials and from this one can calculate when the plant or animal died. The dating system is an indispensable tool for archaeology and also many studies in geology and other earth sciences. Radiocarbon dating is a branch of nuclear chemistry and physics. Since the amounts of carbon 14 are very small, the most sensitive techniques for its measurements are required. Two procedures are currently used, radiometric and accelerator mass spectrometry. Radiometric measures the radiation produced from the disintegration of carbon 14; accelerator mass spectrometry measures the concentration of carbon 14 directly. The figures show the extensive instrumentation involved in each technique as well as an example of the complicated chemistry used in the preparation of samples before measurement.

For both radiometric and accelerator mass spectrometry techniques, pretreatments of the samples can be important. The procedures for this vary widely, depending on the type of material being measured. The steps involve various physical and chemical operations to eliminate extraneous materials. After this, the treatments for the two techniques are different, but both involve high vacuum operations.

For radiometric measurement, the samples are combusted in a specialized vacuum system to produce carbon dioxide. This is then combined with molten lithium to produce lithium carbide. After cooling, the lithium carbide is reacted with water to produce acetylene. This gas is purified and finally converted to benzene using a silica-alumina catalyst. All of these procedures are carried out in glass vacuum systems. The benzene, which contains 92% carbon, is mixed with scintillator chemicals and placed in a liquid scintillation counter for radiation detection. On the average, the sample will remain in a counter for two days in order to accumulate enough counts to give reasonable statistics. Both contemporary standards and background materials are also subsequently measured in the same counters.

Samples for accelerator mass spectrometry are combusted to carbon dioxide, which is then purified. The carbon dioxide is reacted with hydrogen to form graphite in a specialized glass vacuum line. The graphite, 100% carbon, is put into aluminum target holders and placed in the particle accelerator for measurement. The analysis here takes about thirty minutes. As with the radiometric technique, modern and background samples are subsequently measured in the same way.

In addition, all samples are analyzed for the stable isotope, carbon 13. This is essential for adjustment of the measured carbon 14 values. Carbon 13 measurement is an integral part of radiocarbon dating. It is also, in some cases, a means of verifying the source of the bio-mass used for the ethanol production. Carbon 13 itself is not suitable for precisely determining renewable vs. fossil contents in mixtures. Although petroleum and corn, for example, have different carbon 13 concentrations, natural carbon 13 from other bio-mass materials have values are that are quite variable. Some materials suitable for bioethanol production, for example, sugar beets, sweet potatoes, grapes and other fruits, have carbon 13 values that are generally indistinguishable from that of petroleum. This would result in carbon 13 analyses giving ambiguous results in the case of dilutions of bioethanol with ten or twenty percent synthetic ethanol. On the other hand, radiocarbon dating analysis would clearly show this dilution.

The amount of chemical and electronic equipment needed for a routine radiocarbon dating laboratory is quite large. For Beta Analytic Inc., the capitol equipment includes fifty-tree liquid scintillation counters, a particle accelerator with two ion sources, two carbon-13 mass spectrometers with elemental analyzers, eleven benzene synthesis vacuum lines, twelve graphitization vacuum lines and extensive materials and ovens for the pretreatments and combustions.

The important tax credits for bioethanol in gasoline will provide a temptation for unscrupulous individuals to submit synthetic (petroleum) ethanol.

It is anticipated that the most common occurrence will be the dilution of bioethanol with synthetic ethanol in the hope that this will not be detected. However, ASTM D6866 is a quantitative technique that will be able to clearly signal any significant dilution. ASTM D6866 will protect the bio-based industry by discouraging this cheating. An ASTM D6866 certification should be the necessary condition for each batch of bioethanol that is being submitted for the tax credit.