Page 150 - Advances in bioenergy (2016)

of functional types of carbon in the hydroprocessed bio-oil. Through quantitative methods,
carbon can be categorized into saturated and unsaturated carbon, as well as different oxygen-
containing functional types, such as carbonyls, phenolics, ethers, and carboxylic acids.

As for specific chemical components, alkylated benzenes and alkylated cyclohexanes are most
commonly found by gas chromatography-mass spectrometry (GC-MS). Bicyclics, both
saturated and aromatic, are also found by GC-MS. Through the use of other types of liquid and
gas chromatography, other oxygen containing components can be identified in the products.

Physical Properties

Since oxygen plays a big role in the physical properties of the chemical components in the

hydroprocessed bio-oil, physical properties such as density, viscosity and color can be
correlated to the oxygen content in the oil. Density measurement is a simple way to determine
the state of the catalytic processing. Effective hydrodeoxygenation to remove oxygen to levels
of less than 10% will reduce the density of the product to less than 1 g/mL from 1.2 g/mL for
the starting bio-oil; and the trend continues downward with density nearing 0.9 g/mL with 5%
oxygen remaining and closing toward 0.82 g/mL as the oxygen is further reduced to levels
approaching 0. 23

BIO-OIL DERIVED FUELS

Only limited fuel testing has been done on these hydroprocessed bio-oil products due to lack of
product because of the small-scale operations, so far. For example, research products from
tests performed over a 2-year period were collected and segregated to recover sufficient
24
material to distil a gallon of jet fuel range product. In another case, a liter each of an 8.2%,
4.9%, and 0.4% oxygen-containing hydroprocessed bio-oil was produced from products
collected over 4 years. The amount of these products was just sufficient to process through

typically crude petroleum analytical methods first to fractionate them into representative
fractions, and then perform typical fuel analyses. 21

Use as Petroleum Refinery Feedstock

One goal of the analyses mentioned above was to determine the appropriate level of
hydroprocessing required to produce products of sufficient quality to be processed within the
existing petroleum refining infrastructure. A liter each of an 8.2%, 4.9%, and 0.4% oxygen-
containing hydroprocessed bio-oil was produced by collection and combining of products
collected from many bench-scale hydrotreating tests. These products were processed through
typical petroleum analytical methods first to fractionate them into representative fractions of
light naphtha, gasoline, diesel, light cycle oil, heavy cycle oil and resid, and then perform
typical fuel analyses. The study concluded that the 0.4% oxygen product had several options

for refinery processing and should be acceptable feedstock. The 4.9% product had some
interesting possibilities that would need to be analyzed and developed. The 8.2% product was
not considered a reasonable feedstock for existing petroleum refinery operations. 25