23 research outputs found
Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels: Fast Pyrolysis and Hydrotreating Bio-Oil Pathway
This report describes a proposed thermochemical process for converting biomass into liquid transportation fuels via fast pyrolysis followed by hydroprocessing of the condensed pyrolysis oil. As such, the analysis does not reflect the current state of commercially-available technology but includes advancements that are likely, and targeted to be achieved by 2017. The purpose of this study is to quantify the economic impact of individual conversion targets to allow a focused effort towards achieving cost reductions
Low-Temperature Electrochemical Upgrading of Bio-oils Using Polymer Electrolyte Membranes
While bio-oil-derived
fuels hold much promise as a replacement
for petroleum, transformation of the highly oxygenated mixture has
proven challenging. In particular, bio-oils are reactive and difficult
to upgrade through catalytic pyrolysis. To reach a stabilized product
capable of deep deoxygenation at elevated pressure and temperature,
conversion or separation of reactive groups is required. This paper
describes an electrochemical process for stabilization and upgrading
of bio-oils prior to hydrotreating at high pressure and temperature.
This electrolytic process uses a three-compartment cell designed to
hydrogenate reactive carbonyl components while separating small acid
molecules, such as acetic and formic acids, which act as catalysts
for condensation reactions and consume hydrogen gas to produce low-value
gases in hydrotreating. To avoid conductivity issues, electrodes are
appended to anion- and cation-exchange membranes. The cell was tested
using a mixed acetic acid and formic acid surrogate fed to the cathode
compartment, where the decrease in the concentration followed the
applied charge to the cell. Experiments performed using pine pyrolysis
oil demonstrated a significant reduction in the total acid number
(TAN), an increase in pH from 2.6 to over 4, and a modest reduction
of the carbonyl concentration. Analysis showed the reduction in TAN
was primarily due to removal of carboxylic compounds. Experiments
observed a decrease in the reactive carbonyl (aldehydes and ketones)
concentration that followed applied charge. The results with the newly
devised reactor show promise for the electrochemical route for upgrading
bio-oils, but significant improvements in TAN removal and carbonyl
conversion are needed. Given the distributed nature of biomass, an
electrochemical process paired with pyrolysis could be used to densify
and stabilize an oil product near the source. The densified liquid
could then be shipped to centralized refineries for final upgrading
to fuel and/or chemical products
Inductive Effects of Diphenylphosphoryl Moieties on Carbazole Host Materials: Design Rules for Blue Electrophosphorescent Organic Light-Emitting Devices
A Combined Experimental and Theoretical Study on the Activity and Selectivity of the Electrocatalytic Hydrogenation of Aldehydes
A detailed mechanistic
study of the electrochemical hydrogenation
of aldehydes is presented toward the goal of identifying how organic
molecules in solution behave at the interface with charged surfaces
and what is the best manner to convert them. Specifically, this study
focuses on designing an electrocatalytic route for ambient-temperature
postpyrolysis treatment of bio-oil. Aldehyde reductions are needed
to convert biomass into fuels or chemicals. A combined experimental
and computational approach is taken toward catalyst design to provide
testable hypotheses regarding catalyst composition, activity, and
selectivity. Electrochemical hydrogenation mechanisms for benzaldehyde
and pentanal reduction are found to proceed by a coupled proton–electron
transfer process. Initial results show that Au, Ag, Cu, and C catalysts
exhibit the highest conversion to alcohol products. These catalysts
are suitable because they show high cathodic onset potentials for
H<sub>2</sub> formation and low cathodic onset potentials for organic
reduction. Conversion of aromatic aldehydes is found to be appreciably
higher than that of aliphatic aldehydes. Classical molecular dynamics
simulations of solvent and substrate mixtures in an electrolytic cell
were performed to assess how species concentrations vary at the solid/liquid
interface and in the bulk as a function of applied voltage. Results
show that an increase in surface charge in the electrolytic cell decreases
organic and increases water mole fractions at the solid/liquid interface.
In this current study, charged cathodic surfaces result in carbonyl
orientations at the surface that do not favor electron transfer. Repulsion
of organic substrates to the bulk must be compensated by strong adhesion
to the electrode surface. Implications on catalyst choice and process
design are discussed