2011 International Conference on Alternative Energy in Developing Countries and Emerging Economies
- 59 -
Abstract
-- The objective of this research is to study the
effect of operating parameters on recovery of alcohol from
mixed methyl-ethyl esters by using Flash evaporation
technique. The experiments were carried out at pressure
and flow rate in the ranges of 3-7 bar, and 18-25 L/hr,
respectively at 80-100
o
C. Based on the experimental results,
the suitable condition for alcohol recovery is at high
pressure and temperature, and low flow rate. At these
proper conditions, the remained alcohol in biodiesel could
be recovered effectively.
Index Terms
--Alcohol recovery, Biodiesel,
Flash
evaporation
I.
I
NTRODUCTION
Nowadays, the price of crude oil of has become
increasing significantly. Due to the limited amount also
the high demand of using petroleum, the alternative
energy has become interesting significantly in order to
find out the substitute way to commute petroleum, the
exhausting natural resource. Furthermore, some
alternative energy can be produced in Thailand such as
biodiesel and ethanol. This sustainable energy could
reduce the cost of import petroleum and also develop our
country in terms of increase potentiality and income for
Thai people [1].
Biodiesel and ethanol are hydrocarbon compounds that
can be used as the alternative energy of petroleum.
Biodiesel is transformed from vegetarian oil, animal fat,
or used vegetable oil by transesterification reaction.
Generally, this process is reaction between triglyceride in
oil and methanol using sodium hydroxide (NaOH) or
potassium hydroxide (KOH) as a base catalyst under high
temperature in order to produce methyl esters. However
methanol is the imported chemical, so the alternative
alcohol such as ethanol is used. Ethanol can be produced
from domestic agriculture. Sugar is digested from plant
starch such as cassava, cereal or molasses. All sugar are
fermented with microbe
and purified further to get
ethanol. It is shown in some literature that it is possible to
use ethanol instead of methanol in biodiesel production
[2].
According to several previous works, the ethyl ester
production takes longer time than methyl ester
production. However, methyl ester production usually
still has a drawback in terms of its cost. We need to
control this problem by using mixed alcohol between
methanol and ethanol to produce methyl-ethyl ester.
This work was supported by
the Discipline of Excellence (DOE)
Generally, in the biodiesel production using blended
alcohol, 5:1 mole of methanol to ethanol will be used as
the excess reactant
[3]. Therefore this excess alcohol still
remained in the solution
with other products. Then we
need to recover that excess alcohol in order to reduce the
environment problem and also the cost of chemical. In
this work the recovery of mixed alcohol from methyl-
ethyl ester was studied. Moreover, the proper conditions
of alcohol recovery were investigated in order to be
adapted for biodiesel production using mixed methanol-
ethanol[4].
II. M
ATERIAL AND
M
ETHOD
A. Equipment and Chemicals
Flash evaporation technique was used to study alcohol
recovery from mixed methanol-ethanol system of
biodiesel production. The experiment setup for this
experiment is shown in Fig. 1. It consists of a drum tank,
gas supply set, filter, heater, Flash tank with
thermocouple, and condenser. The experiments were
carried out using unrecovered alcohol biodiesel as the
feedstock supported by Prince of Songkla University’s
Biodiesel Research Institution. Basically, the amount of
alcohol presented in the tested biodiesel is about 4.8% wt.
The general information related to calculation of each
component in the tested biodiesel is shown in Table 1,
while the calculation of each component in the tested
biodiesel is shown in Table 2.
Fig. 1. Experimental set up for recovery alcohol using flash evaporation
technique.
Recovery of Alcohol from Mixed Methanol-
Ethanol System of Biodiesel Production
W. Kladtong, C. Tongurai and S. Chongkhong
Faculty of Engineering, Prince of Songkla University,
(Thailand)
