ETHANOL (C2H5OH) - K-Patents

BIOREFINING
APPLICATION NOTE 9.01.00
BIOETHANOL PROCESS
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ETHANOL (C 2 H 5 OH)
Typical end products
Bioethanol fuel (ethyl alcohol) additive for gasoline
Chemical curve: Ethanol R.I. per Conc% b.w. at Ref. Temp. of
20˚C
nD
1.3650
1.3600
1.3550
1.3500
1.3450
1.3400
1.3350
1.3300
0.0 10.0 20.0 30.0 40.0 50.0 60.0
nD
concentration (%)
1.3648
1.3640
1.3632
1.3624
1.3616
1.3608
1.3600
90.0 92.0 94.0 96.0 98.0 100.0
concentration (%)
Introduction
The principle fuel used as gasoline substitute for
road transport vehicles is bioethanol. Ethanol or ethyl
alcohol (C 2 H 5 OH) fuel is mainly produced by the
sugar fermentation process.
Fuel and energy crops are the main sources of sugar
required to produce ethanol. These crops are
specifically grown for energy use and include corn,
maize, wheat, reed canary grass and cord grass.
Waste straw, willow and popular tree sawdust are
also used. Development is also proceeding for the
utilization of municipal solid wastes in ethanol fuel
production.
Application
The Dry Mill process of producing Motor Fuel Grade
Ethanol (MFGE) using corn as the feedstock consists
of six steps.
1. Grinding – Incoming grain is screened and
ground to a course flour in either a hammer mill
or a roller mill. Hammer mills are most
commonly used. Maintaining a consistent grain
size is important in enabling the proper
breakdown of starch into simple sugar for
efficient separation downstream.

BIOREFINING
APPLICATION NOTE 9.01.00
BIOETHANOL PROCESS
www.kpatents.com
2. Cooking – The ground flour is mixed with water
and enzymes. The temperature and the
pressure are raised to 120°C (248°F) and 1-3 br
(10-40 psig) for partial sterilization. The mixture
temperature is then kept elevated at 85-90°C
(185-194°F) for 2-4 hours so the enzymes break
the starch down into simple sugar. The resulting
product is called “mash.”
3. Fermentation – The mash is added to the
fermentation tanks, along with large amounts of
yeast. The yeast converts the sugar into ethanol,
CO 2 and heat. This step can take between 40-70
hours. The resulting product is called “beer”.
4. Distillation – The beer is then distilled by the
application of heat to boil off the ethanol and
separate it from the non-fermentable content.
5. Dehydration – Distillation produces ethanol,
which contains 5% water (190 proof). The water
is then removed by passing the fermented
solution through columns packed with molecular
sieves to produce the 100% (200 Proof) ethanol.
6. Non-fermentables – The non-fermentable
components are separated after distillation using
a centrifuge. After the centrifuge, the solids can
be sold as wet distiller grains or dried to produce
dried distiller grains. The remaining liquid called
thin stillage is recycled back to the slurry tanks.
Installation
The K-Patents Refractometer PR-23-GP/AC can be
installed directly into the main line or in a by-pass.
The K-Patents refractometer gives an instant
indication of concentration levels with excellent
repeatability. A prism wash system is not required.
Instrumentation
Description
K-Patents Sanitary Compact Refractometer PR-23-AC for small pipe line sizes of 2.5
inch and smaller.
The PR-23-AC sensor is installed in the pipe bend. It is angle mounted on the outer
corner of the pipe bend directly, or by a flow cell using a 3A Sanitary clamp or
Varivent® connection.
K-Patents Process Refractometer PR-23-GP is an industrial refractometer for large
pipe sizes and tanks, cookers, crystallizers and kettles. Installation through a flange
or clamp connection.
Measurement range:
Refractive Index (nD) 1.3200 – 1.5300, corresponding to 0-100 % by weight.