Environmental Engineering Reference
In-Depth Information
octane number which is very important for efficiency and balancing the low energy
density of the fuel. Out of all bio alcohols, bio methanol and bio ethanol are most
important (Agarwal
2007
).
4.1.1
Bio Methanol
Bio methanol is an emerging biofuel. Some of the properties which make bio meth-
anol really attractive as a biofuel are that it is a liquid fuel which can be combined
with gasoline and ethanol and used with vehicle equipment at minimal expenses. It
is a high octane fuel having combustion properties that permit engines specifically
designed for methanol fuel to work at the best efficiencies and regulating pollutant
release. It can be produced from renewable biomass, is a safe fuel though toxic but
the toxicity is comparable to or better than gasoline, and biodegrades quickly in
case of a spill and doesn't persist in surface waters. Bio methanol is a greenhouse
gas reduction fuel as the fuel just returns the carbon back into the surroundings
when formed from a renewable resource (Agarwal
2007
).
The Partial Oxidation and Gasification Using Water and Oxygen
The main
method used for the making of bio methanol via biomass is by its partial oxidation
and gasification. The plant comprises of two chief parts in which the process is car-
ried out. First is a biomass gasifier in order to transform the feedstock to synthesis
gas (syngas) and second one is a methanol production plant. Biomass resources
usually used are wood components including wood wastes. The oxygen required for
the conversion of biomass into gas is obtained from electrolysis of water by con-
suming electricity. About 10.32 kt of oxygen gasifies 10.1 kt of biomass yearly. The
complete output of biomass derived methanol can be improved by more electrolytic
oxygen supply. The fume from the gasifier consists of elements like tar, alkali, sul-
phur and chloride complexes. These particles can lead to poisoning of the catalysts
and cause corrosion of the equipment being used. Hence the minor particles using
the gas are formed, which are its principal investments, compulsory for the treat-
ment of the syngas (Demirbas
2009a
,
b
).
The presence of nickel based catalyst reforms natural gas, tar and additional hy-
drocarbon compounds into carbon monoxide and hydrogen gas at extreme tempera-
ture. The addition of hydrogen helps to regulate the appropriate hydrogen:carbon
monoxide percentage for methanol production. 1.29 kt amount of hydrogen is used
for the manufacture of 12.2 kt of methanol annually (Cifre and Badr
2007
).
Methanol processer uses catalytic conversion of syngas for methanol manufac-
ture. The key benefits of this technology are low production cost and improved
working reliability. The unpolished methanol is treated in a distillation chamber to
attain good quality. The gas turbine can be used in order to consume the residual gas
for electricity production (Cifre and Badr
2007
).
Bio methanol manufactured using this process is at least 2-3 times extra costly
than methanol formed by fossil fuel. Methanol competes with the fossil fuels only
under a green assessment based on pollutant released, mainly involving carbon
dioxide, which favors the manufacture of methanol using biomass. Some new
