American Oil and Gas Reporter - October 2019 - 82

SpecialReport: Oil Field Chemistry
saccharides, occur naturally.
One of the more commercially intriguing bio-based polymers is polylactic
acid (PLA). Although it was discovered
in 1845, PLA was not commercialized
until the early 1990s. Its unique and appealing characteristics include good transparency, a glossy appearance, high rigidity
and the ability to tolerate various processing conditions.
PLA is widely used in food packaging,
including food trays, water bottles, candy
wrappers and tea bags. More recently, it
has been employed as a membrane material in the automotive and chemical industries. In its oil field incarnations, the
polymer appears in fluid loss control and
fluid diverting agents, frac sand and proppant carrier agents, filter cake removers
and degradable objects.
Like PLA, polyhyroxyalkanoates
(PHAs), a family of polyesters produced
by bacterial fermentation, have migrated
to the oil field. PHAs occur naturally in
a variety of organisms. The most efficient
producers can be isolated and commercially-fermented to maximize the PHA's
quality and yield.
Polyhyroxybutyrate, the simplest PHA,
was discovered in 1926 by Maurice
Lemoigne as a constituent of the bacterioum bacillus megaterium. Additional
PHA monomers have since been identified,

and this diversity allows the production
of multiple bio-based polymers with a
wide range of properties tailored for specific applications.
PHA possesses similar thermal and
mechanical properties to polystyrene and
polypropylene. PHAs are therefore suitable for a wide range of food and medical
packaging applications, as well as disposable items such as hot cup lids, forks,
spoons, knives and cosmetics. PHA and
its copolymers are widely used as biomedical implant materials and drug delivery systems. In the oil industry, PHAs
are used for filter cake removal, as internal
breakers to decrease the viscosity of
completion fluids, and to encapsulate
chemical additives for controlled chemical
release applications.
Biosolvents
Solvents are a vital ingredient of many
chemical processes and products. They
are used in a variety of industrial applications, including agrochemicals, paints
and coatings, household and industrial
cleaners and pharmaceuticals. Nowadays,
consumers can choose solvents not only
based on their physical properties, but
also on their environmental impacts.
Many consumers prefer eco-friendly solvents or green substitutes for conventional
products. In this new era, biosolvents

FIGURE 1
Examples of Bio-Derived Solvents

82 THE AMERICAN OIL & GAS REPORTER

are becoming more widely used because
they pair eco-friendly characteristics with
lower costs.
For a solvent to be considered green,
it must meet several criteria. It should be
bio-based, free of volatile organic compounds, nontoxic, biodegradable and recyclable. Green solvents can include a
variety of products (Figure 1), especially
bio-based ethanol, D-limonene, dipentene,
and methyl soyate.
While methyl soyate (soy fatty acid
methyl esters) is gaining market share
rapidly, many manufacturers currently
prefer bio-based ethanol because its widespread commercialization makes it a more
affordable and convenient purchase. It
helps that bio-based ethanol is suitable
for a multitude of applications. Ethyl lactate is another green solvent that is growing
in popularity, primarily as a replacement
for petroleum solvents.
Recently, the Circa Group, a company
that offers solutions for converting waste
biomass into advanced biochemical materials, has introduced a bio-based dipolar
aprotic solvent, Cyrene, that offers an alternative to petroleum-derived dimethylformamide and N-Methyl-2-pyrrolidone
products. These products are used to produce pharmaceuticals, pigments, paint
strippers and adhesives.
One of the more exciting use cases
for green solvents is in dry cleaning. Traditional dry cleaning solvents produce
harmful waste products including carbon,
dyes, grease and various filter materials.
But thanks to Green Biologics, dry cleaners
now have access to a bio-based solvent
(methylene glycol dibutyl ether) made
from corn. Called SOLVONK4, it cleans
better than traditional solvents, does not
harm the environment and minimizes
health-related concerns. Moreover, it is
the first and only bio-based solvent to be
used for dry cleaning.
Various biosolvents, including Dlimonene, dipentene, lactic acid esters
and fatty acid esters, have been used in
the oil field to improve efficiency in oilbased drilling muds and remediation and
stimulation fluid systems. Such fluid systems are helping remove pipeline deposits,
remediate paraffin and asphaltene deposits
and clean tanks.
Bio-based solvents have been employed

American Oil and Gas Reporter - October 2019

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