CNDREXEL LOG

9/23/2010
I plan to look at properties of ethanol for the first assignment.
My research topic will be something relates to conversion of cellulose to ethanol using enzyme cellulase.



Assgiment #1

Sigma-Aldrich ethanolmp.bmp [why not use the refractive index from sigma? JCB] Because it's at 20 C.
Melting point: -114 °C
Boiling: 78 °C
Density: 0.789 g/mL at 25 °C
Flash point: 14 °C
Refractive index: nD 1.35927 (25 °C) http://www.springerlink.com/content/r4181605400x25p0/fulltext.pdf

Handbook of Chemistry and Physic http://www.hbcpnetbase.com//articles/03_01_91.pdf#xml=http://www.hbcpnetbase.com/search
ethanolpropertiesHB.bmp
Melting point: -114.14°C
Boiling: 78.29 °C
Density: 0.78509 g/ml at 25 C http://pubs.acs.org/doi/abs/10.1021/je00056a016
Flash point: 16.6 °C http://fscimage.fishersci.com/msds/89308.htm
Refractive index: nD 1.35944 (25 °C) http://pubs.acs.org/doi/pdf/10.1021/ja01304a051


Oxford MSDS http://msds.chem.ox.ac.uk/ET/ethyl_alcohol.html
Melting point: -114 °C
Boiling: 78 °C
Density: 0.78534g/ml (25 °C) http://pubs.acs.org/doi/abs/10.1021/je00018a004
Flash point: 14 °C
Refractive index: nD 1.35912 (25 °C) http://pubs.acs.org/doi/abs/10.1021/j150449a003

Wikipedia http://en.wikipedia.org/wiki/Ethanol
Melting point: -114.3 °C
Boiling: 78.4 °C
Density: 0.78529 g/ml (25 °C) http://pubs.acs.org/doi/pdfplus/10.1021/je8006698
Flash point:13 °C
Refractive index: nD 1.36 (25 °C)

Merck Index ethanolproperties2.bmp
Melting point: -114.4°C
Boiling: 78.32°C
Density: 0.7851 g/ml (25 °C)
Flash point: 61°F = 16.1 °C
Refractive index: nD 1.3596 (25 °C)

Summary assignment
Article link: http://www.owr.ehnr.state.nc.us/ref/24/23894.pdf
[Full marks JCB]

Title: Fuel Ethanol from Cellulosic Biomass
Abstract: Cellulosic ethanol from cellulosic biomass can be seen as an alternative transportation fuel because it is an abundant source, environmental friendly and it helps balancing energy. However, cellulosic ethanol conversion is still very costly and so this article proposes some ways to better produce cellulosic ethanol.
Introduction
  • Ethanol can be produced not only from sugar cane, corn or starch but also from cellulosic biomass. The promising of cellulosic biomass to cellulosic ethanol conversion is evaluated.
  • America depends mostly on petroleum for transportation.
  • It’s necessary to find an alternative fuel source that reduces air pollution.
Ethanol as a Fuel
  • Ethanol fuel can now be cost competitive. With ethanol in gasoline, the price is lessened by more than $.50 per gallon by federal and state tax inducement.
  • A 10% ethanol in gasoline mixture is mandated in the United States and this mixture seems to help with combustion completion in old cars.
  • A higher amount of ethanol in gasoline, even 100%, is also used in some part of the U.S, Brazil and Europe.
  • Alcohols in gasoline seem to help spark-igniting engines and provide better thermal effectiveness in internal combustion engines.
  • Compared to gasoline, more gallons of ethanol are needed for the same distance so it is necessary that ethanol price should be cheaper than gasoline.
  • Ethanol and methanol are more environmental friendly than gasoline. It is reported that the air toxic is lessen and the urban ozone levels are improved when using these alcohols.
Biomass Feedstocks
  • Some sources to make ethanol are wood, municipal solid waste and corn. Yield of mass of potential ethanol per mass of dry feedstock is 0.33, 0.25 and 0.35 accordingly.
  • Ethanol from corn is attractive at small scale levels but can’t be considered a good alternative fuel source.
  • Ethanol yield from wood is about the same as from corn but ethanol from wood only need less than half of energy input.
  • A small amount of ethanol production comes from primary waste such as municipal solid waste, agricultural and forestry residues.
  • Ethanol production also comes potentially more from non-waste cellulosic material such as wood, tree or herbaceous high productivity energy crops (HPECs).
  • Excess cropland is estimated to give about 11.4 quad of ethanol and is a potential source. Forest land is less wanted because wildlife habitat might have to suffered when using that land.
  • Cellulosic ethanol can be potentially produced from cellulosic materials including crops, wastes and wood.
  • Perennial crops have more environmental benefits than annual row crops.
Ethanol Production from Cellulosic Materials
  • There are 2 methods: acid hydrolysis and enzymatic hydrolysis to break cellulosic materials to ethanol. Enzymatic hydrolysis is a newer and preferable approach and needs more research on.
  • R is the ratio of energy output to energy input. R for ethanol conversion from cellulose is 5 whereas R for ethanol conversion from corn is less than 1.
  • Cellulose residues after fermentation steps can be burned to give thermal energy.
  • The CO2 released during the process are used for photosynthesis for feedstock growth so less CO2 emission.
  • Ethanol is not as toxic as methanol and gasoline
  • Suggesting ways to reduce cost:
  • Reduce inhibition of enzyme on the product.
  • Improve all steps: pretreatment, enzymatic hydrolysis then microbial fermentation. The authors suggest to research more on enzymatic hydrolysis step
  • Improve cellulase enzyme, naturally or genetically modified it
  • Minimizing enzyme cost also results in a lower cost for hydrolysis and fermentation steps.
  • In all, improvement in any step can advance the whole process and will be beneficial to cost reduction
Concluding remarks
  • Cellulosic ethanol is an abundant alternative fuel source. It provides good effect on the engine as well as the environment.
  • Cellulosic ethanol conversion still needs more research and attention of more scientists.

CHI NGUYEN