Abstract
Lignocellulosic biorefineries can be an important piece of the puzzle in fighting climate
change. Present, biorefineries that produce ethanol from lignocellulose are challenged
in working on market terms as the two product streams ethanol and lignin are low
value products. The aim of this project has been to increase the value of the lignin
stream. Recent regulations on shipping exhaust gasses in coastal waters dictate lower
sulfur emissions which require ships to use low sulfur fuels for propulsion. This opens
or expands a very large market for low sulfur fuels because a shift from traditional
sulfur containing bunker fuel is needed. The lignin stream from lignocellulosic
biorefineries could provide a source for the production of sulfur free fuels and this is
what has been explored and demonstrated in this PhD project.
The chemical reactions taking place in lignin during hydrothermal pretreatment of
wheat straw has been investigated by size exclusion chromatography and NMR
spectroscopy. It was found that contrary to literature reports on hydrothermal
pretreatment of hardwood the lignin in wheat straw depolymerizes. The argument for
this depolymerization is that unlike hardwood lignin, grass lignin (e.g. wheat straw)
contains tricin that can act as a polymerization inhibitor during pretreatment.
A solvolysis reaction involving ethanol and hydrothermally pretreated wheat straw
lignin from the pilot scale biorefinery Inbicon in Denmark was tested at lab scale. Here
it was found that in a batch reactor it is possible to produce a biooil from lignin. Yields
up to 85 % were achieved at very low lignin loadings (2 g lignin in 100 ml) in ethanol. At
higher loadings of 10–40 g lignin in 100 ml ethanol yields between 40 and 20 % were
achieved. Further the oil was found to be more deoxygenated at higher loadings. The
effect of increased reaction time was found to be beneficial for oil yields but also
caused an increase in solvent consumption and so there is a trade-off where a
compromise has to be found in the event of an up scaled reaction. The reactions that
cause solvent consumption during the process were identified and this knowledge
might help to lower solvent consumption in future processing. From these batch
reactor results it was found that solvolysis of hydrothermally pretreated lignin in a
primary alcohol holds a large potential and two patent applications were filed and two
manuscripts for publication of the results were prepared and is presented here.
change. Present, biorefineries that produce ethanol from lignocellulose are challenged
in working on market terms as the two product streams ethanol and lignin are low
value products. The aim of this project has been to increase the value of the lignin
stream. Recent regulations on shipping exhaust gasses in coastal waters dictate lower
sulfur emissions which require ships to use low sulfur fuels for propulsion. This opens
or expands a very large market for low sulfur fuels because a shift from traditional
sulfur containing bunker fuel is needed. The lignin stream from lignocellulosic
biorefineries could provide a source for the production of sulfur free fuels and this is
what has been explored and demonstrated in this PhD project.
The chemical reactions taking place in lignin during hydrothermal pretreatment of
wheat straw has been investigated by size exclusion chromatography and NMR
spectroscopy. It was found that contrary to literature reports on hydrothermal
pretreatment of hardwood the lignin in wheat straw depolymerizes. The argument for
this depolymerization is that unlike hardwood lignin, grass lignin (e.g. wheat straw)
contains tricin that can act as a polymerization inhibitor during pretreatment.
A solvolysis reaction involving ethanol and hydrothermally pretreated wheat straw
lignin from the pilot scale biorefinery Inbicon in Denmark was tested at lab scale. Here
it was found that in a batch reactor it is possible to produce a biooil from lignin. Yields
up to 85 % were achieved at very low lignin loadings (2 g lignin in 100 ml) in ethanol. At
higher loadings of 10–40 g lignin in 100 ml ethanol yields between 40 and 20 % were
achieved. Further the oil was found to be more deoxygenated at higher loadings. The
effect of increased reaction time was found to be beneficial for oil yields but also
caused an increase in solvent consumption and so there is a trade-off where a
compromise has to be found in the event of an up scaled reaction. The reactions that
cause solvent consumption during the process were identified and this knowledge
might help to lower solvent consumption in future processing. From these batch
reactor results it was found that solvolysis of hydrothermally pretreated lignin in a
primary alcohol holds a large potential and two patent applications were filed and two
manuscripts for publication of the results were prepared and is presented here.
| Originalsprog | Engelsk |
|---|
| Forlag | Department of Geosciences and Natural Resource Management, Faculty of Science, University of Copenhagen |
|---|---|
| Antal sider | 257 |
| Status | Udgivet - 2017 |