Biomass is a renewable energy source with great potential. One of the promising ways for the conversion of biomass into more suitable forms of energy is its pyrolysis. Liquid products of the biomass pyrolysispyrolysis oils (or bio-oils) could be used in the future as biofuel or as feedstock for valuable chemicals. Detailed knowledge about their chemical composition is crucial, as it can facilitate the design of processes for the necessary upgrading of bio-oils. This paper outlines current knowledge about the composition of bio-oils and presents an overview of the commonly used analytical methods and procedures for the characterization of the liquid pyrolysis products of biomass. The capabilities and limitations of these methods are discussed as well.
Ethanol–gasoline
blends (EGBs) can easily absorb large amounts
of water because of the presence of ethanol. Acidic compounds and
ions can be dissolved in water, and these substances can have corrosive
effects on metallic construction materials. With the increasing content
of ethanol in fuels, the conductivity and ability of fuel to absorb
water increases, and the resulting fuel is becoming more corrosive.
In this work, we tested E10, E40, E60, E85, and E100 fuels that were
prepared in the laboratory. These fuels were purposely contaminated
with water and trace amounts of ions and acidic substances. The aim
of the contamination was to simulate the pollution of fuels, which
can arise from the raw materials or from the failure to comply with
good manufacturing, storage, and transportation conditions. The corrosion
properties of these fuels were tested on steel, copper, aluminum,
and brass using electrochemical impedance spectroscopy and Tafel curve
analysis. For comparison, static immersion tests on steel were also
performed. The main parameters for the comparison of the corrosion
effects of the tested fuels were the instantaneous corrosion rate;
the polarization resistance; and the corrosion rate, which was obtained
from the weight loss occurring during the static tests. In most cases,
E60 fuel showed the highest corrosion activity.
Conditioning rapeseed can significantly increase the amount of bioactive compounds in the crude oil, but if the conditioning temperatures are too high, they can cause unwanted side effects such as darker color and sensory defects. Modest conditioning temperatures may be more suitable, but little is known about the effects on the quality and bioactive composition of the resulting oil. Oil was recovered from five rapeseed cultivars by cold pressing (CP) or by pressing seeds conditioned at 80 °C for 30 min (HP). Conditioning rapeseed increased oil yield without changing fatty acid composition and increased the amount of total sterols by 16 %, total tocopherols by 20 %, and the levels of polyphenols. Levels of the polyphenol canolol were up to 55‐fold higher in HP oil than in CP oil. These higher levels of bioactive compounds gave HP oil higher radical scavenging activity. Although HP oil also had higher free fatty acid contents, peroxide levels, and specific UV extinctions (K values). The quality parameters of HP and CP oils were within codex limits indicating high quality. Modest conditioning temperatures can be used to produce rapeseed oil with high quality and radical scavenging activity.
Pyrolysis
bio-oils could be used in the future as biofuels or as a source of
valuable oxygen-containing chemicals. To facilitate efficient exploitation
of bio-oils, a detailed understanding of their structure is necessary.
Over the past decade, petroleomic analysis has been widely applied
to characterize pyrolysis bio-oils from the lignocellulosic biomass.
Typically, a petroleomic analysis has been performed using high-resolution
mass spectrometry (HRMS). HRMS has enabled the researchers to determine
the molecular weights and molecular formulas of thousands of less
volatile and nonvolatile, high-molecular-weight bio-oil compounds
to obtain structural information that cannot be obtained using any
other method. Here, we discuss the theoretical principles of HRMS
and present an overview of the investigations regarding the petroleomic
characterization of pyrolysis bio-oils and their key findings. In
addition, this review outlines the current knowledge of the structure
of bio-oil compounds detectable by HRMS. This could help us to understand
the chemical composition of bio-oils in more detail and facilitate
the design of processes for bio-oil upgrading and further utilization.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.