“To-mah-toe, to-may-toe…”: Consequences of valorizing biobased carbon over biobased matter : Biofuels Digest

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By Michael A. Fatigati, Special to The Digest

It’s not news to the readers of Biofuels Digest, but it bears repeating that we find ourselves in an age of heightened awareness of the impact of drawing down the fossil carbon savings account of our precious blue orb as quickly as we’ve managed to do in recent years. With the growth of civilization and technology, our energy requirements ‘naturally’ grew along with the increased need for inexpensive transportation, food production and delivery, communication, and creature comforts. We now find it necessary to throttle back our drawdown of the fossil carbon account to preserve our climate and through reasoned and sensible policies and regulation moving us towards use of non-fossil or “living” carbon sources of energy and materials

An example of this policy is the USDA’s BioPreferred Program[1]which is intended to encourage our government agencies to purchase those supplies which are made with “modern”, or “living”, carbon. To quantify the content of these materials that is and is not “living” carbon, we look to ASTM 6866(18) for guidance which provides a radiographic means of measuring the C14(“living”) content of a given sample to compare with its C12(“dead”) content. It is a somewhat peculiar outcome of nuclear bomb development programs that the production of C14during those atmospheric tests could be quantified and then measured as the C14became part of all living creatures through their processes of respiration and metabolism. Having established a baseline for available C14in the environment and understanding the time required for decay to C13and C12, it became possible to identify something as comprised of “dead” or of “living” carbon. Several companies now provide the service to conduct the ASTM 6866 test to report on a given sample’s “biobased” or “biogenic” carbon content.  Specifically, “biobased” carbon relates to the ratio of C14in a sample to total organic carbon while “biogenic” carbon relates to the ratio of C14to its total carbon (including inorganic carbon) in the sample. Simple and straightforward, right?

Surprisingly, these very specific definitions have created an ambiguity in how we use these terms. For example, the United States Army has recently issued a bio-friendly specification[2]for a CLP[3]product with a minimum 33% “biobased” content with the intent to increase their use of renewable, less toxic products. Throughout the specification, reference is made to “biobased content” and not “biobased carbon”. Quite naturally, ASTM 6866 is given therein as a reference method with which to provide data for qualification.

An ambiguity now arises in the MilSpec entirely due to lack of the term “carbon” in the phrase “biobased content”. Following the procedure described with within ASTM 6866, one reports either the C14/C12or C14/(C12+C14) ratio as a measure of the living carbon content of the tested sample. One can also report biobased carbon content as a fraction of total mass.

Let’s consider a simple example to make the point. It is entirely reasonable to consider a kilogram of Kentucky’s best (or worst, for that matter) to be 100% biobased; that is, deriving entirely from a biological fermentative process. A sample of this sent for radiographic analysis of biobased carbon could be expected to provide the result that 100% of the carbon found is indeed living (reported as 100% biobased carbon content) – so far, so good.  However, combine that ethanol with an equal mass of, say, petrochemically-derived diesel fuel and the question becomes slightly ambiguous. There should be no question in anyone’s mind that the combination of a kilogram of corn ethanol with a kilogram of diesel fuel would result in a 2 kilogram mixture of which 1 kilogram was entirely “biobased”…..and reasonably represented as “50% biobased”.

Digging in a bit deeper, 1 kg of ethanol represents 21.7 moles of ethanol (chemical formula C2H5OH, MW=46) and 1 kg of diesel represents 6 moles (using the generic chemical formula for diesel:  C12H23, MW=167). One mole of ethanol contains 2 moles of C, so that 1 kg of ethanol contains 2*21.7, or 43.46 moles of modern carbon.  Here, the use of the term “modern carbon” infers  a simplication. “Modern carbon” refers to the combination of C12, C13and C14isotopes in fractions that correspond to those identified today as “modern carbon” through comparison with the accepted oxalic acid standard.

One mole of fossil diesel contains 12 moles of fossil carbon, so that 1 kg of diesel contains 12*6, or 72 moles of C12. According to ASTM 6866, this mixture contains 43.46/(43.46+72), or 37.6% biobased carbon content, where C14 is measured as a percentage of total organic carbon.

Which reported value (50% or 37.6%) is more meaningful for our march to increasing sustainability?

The calculation resulting in the value of 37.6% is clearly biased toward counting carbon atoms and ignoring the other ‘biobased’ elements that are clearly the products of a living process. However, it is also certainly true that the oxygen and hydrogen that were used by S. cereviscaeto ferment sugar to ethanol (and CO2!) is part of the process and may be considered as ‘biobased’. However, our focus on a reduction of atmospheric CO2levels has resulted in development of accounting tools that only consider carbon.

Let’s consider a case similar to one I have recently witnessed regarding a new product made up of several organic compounds. Let’s also assume that we needed to target 50% biobased content for success in the USDA BioPreferred Program. A well mapped out program of product development resulted in a candidate that seemingly met all the necessary criteria and featured superior performance characteristics over its non-bio brethren. The following table summarizes the calculations (as described in ASTM 6866).

Now, let’s also assume that this is the maximum ‘biocontent’ that the aggregate HLB[4]of the system will allow for stability. More than 51.7% of its mass is certainly ‘biobased’….but we’ve missed the mark for % biobased carbon by 2.8%. After all the resources expected to develop this product, have we failed in this attempt to meet the ‘bio’ spec for this new product? Do we fire the R&D team and commit to reformulate at additional cost of resources? Do we abandon the project? Is there no value in the product as so far formulated?

Or, is there a ‘fix’ to the problem that is not obvious, a bit outside the box, yet still compliant with requirements?

Suppose that we substitute one of our components (“Component A”) with another that has similar physical and chemical properties and that, upon substitution, the resulting compound fulfills all target performance specifications. Let us posit further that we used perchloroethylene (“PCE”) as the substitute[5]. The resulting % biobased carbon content looks like this:

We have just ‘increased’ the biobased carbon content on this formula from 47.2% to 68.9% with the substitution of one of the organic compounds with PCE, a chemical that is under scrutiny from the US EPA, NIH, and other agencies. While technically correct but certainly on shaky ethical ground, we now fulfill the requirement of a minimum 50% biobased carbon content and may have reduced the raw material cost of the new product by using PCE over a more costly ingredient, creating a more competitive product.  We also have most certainly have gone astray of the original intent of policy program like the USDA BioPreferred Program which, at a high level, can be said to promote the use of chemicals and fuels that arise from living feedstocks.

A focus on carbon at the expense the other elements present in a biologically derived molecule that may not have an impact on global warming seems to have the unintended consequences of:

  • Creating a situation where it may be possible ‘cheat’ on the development of a product with “bio” content by adding otherwise unwanted components; and,
  • Preventing otherwise acceptable biologically derived molecules from use in products because of the content of other elements like nitrogen, oxygen, and hydrogen within the molecule that might bias a report of % biobased carbon content as derived by ASTM 6866.

The goal of increasing our global use of sustainable and renewable products is laudable and demonstrates good stewardship of the available resources at hand. Is it too complex to have a single regulation that both reduces atmospheric warming components and reduces use of materials that cause other environmental damage?  While for regulatory efficacy and clarity it is often more convenient to separately regulate the use of unstainable or harmful materials, we all, including regulators, need to be more thoughtful on the standards and specifications we impose to achieve that goal. At the very least, this should serve to remind those seeking to improve their products by adding biocontent to carefully and fully understand those standards and specifications.

About the author:

Michael A Fatigati has served at Fortune 100 companies and at several fast-moving start-ups to advance the use of renewable feedstocks in our energy and product mix.  He has an outstanding 30 year track record of project and technology development in biomass, bio-derived chemicals, bioenergy, biofuels and power development arenas, including significant contributions to advanced ethanol production from cellulosic feedstocks, thermochemical conversion of biomass for the purposes of energy generation and biofuels production. Mike has worked to also advance the use of algae for the production of cosmeceuticals and nutraceuticals.

He significantly contributed to the startup of two 2ndgeneration cellulosic-ethanol pilot plants in Japan (>2 TPD) for the production of ethanol from wood chips.  He has worked in the areas of project development including development of a first of a kind concentrated acid hydrolysis facility for ethanol production and a pioneer 10 MMGPY corn-to-ethanol plant in California.  He actively consults for domestic and international banking and industrial clients, including private equity interests.  He currently serves as Director Product Development and R&D for QMaxx Products Group, Inc. and oversees their transition from the use of petro-derived solvents and oils to those that are biobased.

[1]https://www.biopreferred.gov/BioPreferred/

[2]MIL-PRF-63460(F), issued 31 March 2017.

[3]Firearms enthusiasts will recognize the abbreviation for a three-in-one product that can (C)lean, (L)ubricate and (P)reserve metal from rust and corrosion.

[4]HLB = ‘hydrophyllic-lipophyllic balance’ is determined based on calculation of a value pertaining to the chemical groups of molecules and describes the relative stability of components when mixed together in an emulsion.

[5]The associated % Organic Carbon Content is derived from the formula for PCE (C2Cl4, MW=165.83), or 2*12/165.83, or 14.5%. PCE is made today through the high temperature chlorinolysis of light hydrocarbons from fossil sources.  PCE, or dry-cleaning fluid, is banned in California from use in dry-cleaning, though it is still in use in other industries, and faces similar regulatory pressure around the world due to its listing as a Group 2A carcinogen.  It is a soil contaminant more difficult than oil to remediate.



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