EXERGETIC
ECONOMIC ANALYSIS OF BIODIESEL PRODUCTION FROM BOTH FRESH AND WASTE GROUNDNUT
OIL USING ALKALI CATALYST METHOD
Department: Economics
CHAPTER
ONE
1.0 INTRODUCTION
Biodiesel is produced from biological source such as
vegetable oils, animal fats and waste cooking oils using biochemical process
known as transesterification. It is the mono alkyl esters of fatty acid (MAEFA)
gotten when any of the biological source react chemically with an alcohol to
produce fatty acid alkyl esters and glycerol. If waste groundnut oil reacts
with an alkanol (methanol), biodiesel and glycerol are produced as end products
(Jonvan. 2005). Due to the higher demanding of energy and pollution problems by
the use of fossil fuel, as a result, it become necessary to develop an
alternative fuel which is a renewable energy source that is non-toxic fuel,
biodegradable and environmentally friendly fuel used in diesel engine.
Biodiesel does not contain any sulphur or aromatic compound and its combustion
results in lower emission of carbon monoxides, hydrocarbons and particulates,
which reduces greenhouse gas effect and does not contributes to global warming
due to lesser emission (Sharama and Singh, 2009; Suppalakpanya et al., 2010). Biodiesel can be used easily and safely
stored as a fuel in addition to its when compared to fossil fuel which affects
the environment negatively (Ozcimen and Yucel, 2010). No fuel system
modification or engine conversion is needed to run the biodiesel on
conventional diesel engines, biodiesel as an alternative fuel developed to
reduce the challenges of environmental and higher demanding of fossil fuel, it
became recognizable and attracted more attentions because of it renewable
nature and it performance efficiency in diesel engines; biodiesel can be used
as pure or mix with diesel fuel in unmodified diesel engines and it reduces
some exhaust pollutants which are emitted to atmosphere as compared with fossil
fuel exhaust emissions (Agarwal and Das, 2001). Biodiesel has a relatively high
flash point (15 OC) which makes it less volatile and safer to
transport or handle than petroleum based diesel (Krawczyk, 1996). It provides lubricating
properties that can reduce engine wear and extend engine life (Von Wedel, 1999)
in brief, these merits of biodiesel makes it a good alternative to petroleum
based fuel and led to its use in many countries, especially in environmentally
sensitive area (Roseman, 2009). Biodiesel is a very modern and technological
area for researchers due to the relevance that it is wining every day because
of the increase in the petroleum price and environmental advantages, it
describes sustainable feedstock options for production and improved conversion
technologies (Siti, 2009). The advantages of biodiesel as diesel fuel are it
portability, higher combustion efficiency, availability, renewability, higher
cetane number, lower sulphur and aromatic content and higher biodegradability
(Siti, 2009). The main disadvantage of biodiesel as diesel fuel are its higher
viscosity, lower energy content, higher cloud point and pour point, higher
nitrogen oxide emission, lower engine speed and power, injector caking in
engine compatibility and higher engine wear (Mustafa and Havva, 2010). The rate consumption of fossil fuel which is
faster than it can be replenished and their environmental pollution effect lead
to the usage of an alternative renewable energy source in the recent years,
biodiesel is an important renewable energy source that has being commonly
produced presently in many countries of the world such as Germany, France, USA,
Italy, Australia, Brazil, Argentina and Malaysia. With Germany and France as
the two leading biodiesel producers in European countries (European Biodiesel
Board, 2010) 1.9 million tone biodiesel were produced in European Union
countries in 2009. Biodiesel is generally produced from different sources such
as plant oils: Soybean oil (Silva et al.,
2010, Cao et al., 2005, Lee et al., 2009) cottonseed oil (Dube et al., 2007; Issariyakul et al., 2008) sunflower oil (Madras et al., 2004) linseed oil (Veljkovic et al., 2006) palm oil (Melero et al., 2009) recycled cooking oils
(Rahamanlar, 2010; Zhang et al.,
2003; Demirbas, 2009) and animal fats.
Transesterification reaction process is one of the
method used in biodiesel production. This process is conventional and most
common method as a homogeneous catalyst (alkali or acid) or heterogeneous
catalyst (Ozcimen and Yucel, 2010). In transeterification process fatty acid alkyl esters are produced by the
reaction of triglyceride with an alcohol (ethanol or methanol) in the present
of alkali, acid or enzyme catalyst (Ozcimen and Yucel, 2010). The sodium or potassium
hydroxide which dissolved in alcohol, is generally used as catalyst in this is
process ( Dubo et al., 2007) the
product of the reaction are fatty acid methyl esters (FAME) which is the
bioldiesel and glycerol (Vicente et al.,
2004). Ethanol can be used as alcohol instead of methanol if ethanol is used
fatty acid ethyl ester (FAEE) is produced as product. The alkali catalysed
transesterification reaction proceeds faster than acid catalysed
transesterification and it is the one most commonly used commercially (Ozcimen
and Yucel, 2010). The most commonly alkali catalyst used are NaOH, CH3ONa
and KOH, the sodium hydroxide and potassium hydroxide. Alkyl oxides solutions
of sodium methoxide or potassium methoxide in methanol which are now
commercially available are preferred catalyst for large continous flow
production processes (Singh et al., 2006).
Energy analysis is a method of evaluating the energy
requirement in either a physical or chemical process operation. It involves
carrying out energy balance of a system in which energy requirement is
determined in every process unit (Dincer and Rosen, 2007). This analysis is
based on first law of thermodynamics that helps in evaluating the efficiencies
of the energy and aids the analysis of processes, system and devices for energy
transfer and transformation to take place with no information on the degradation
of energy resources and can not estimates the quality of energy stream flowing
through the system (Dincer and Rosen, 2007).
Exergy analysis is a potential tool based on the
second law of the thermodynamic which highlights related possibilities and
understanding means of identifying, assessing and comparing of processes and
systems (Dincer and Rosen, 2007). Exergy is the most reliable tool of assessing
the performance of thermodynamic resources, it is the maximum amount of useful
work which can be produced by a flow of matter or energy as it comes to
equilibrium with a reference environment (Dincer and Rosen, 2000). This
analysis identifies the primary sources of loss and provides more accurate
performance relative to the theoretical ideal (Dincer and Rosen, 2007). The
true measure of how closely actual performance approaches the ideal are gotten
from the efficiencies produced by exergy analysis and identified more better
than the energy analysis the cause and locations of the thermodynamic losses
(Dincer and Rosen, 2007). However exergy analysis help in improving and
optimizing system designs and processes (Dincer and Rosen, 2007). Exergy
analysis has been used in the design, simulation, evaluation of energy
performance of a system, it is also employed to detect and evaluate
quantitatively the cause of the thermodynamic irreversibilities in a system
under the consideration (Dincer and Rosen, 2007). This analysis indicates
improvement possibilities of thermodynamic system and overcomes the limitation
of the first law of thermodynamic; it also can quantify the quality of heat in
a waste stream, (Dincer and Rosen 2007). The purpose of exergy analysis is to
identify exergy efficiency, cause and true magnitudes if exergy losses. At
steady state of a system, the evaluation of exergy for ethylene process and
refrigeration system was conducted at three different ways such as the unit
operation level, the subsystem and overall process (Hsuan, 2007)
Economic Analysis has long been considered as one of
the most important element in production valuation, feasibility studies and
production corporate decision in industries; and in establishing plant and
equipment capacities of biodiesei production (Yii-Der et al., 2007). The cost estimation relationship in economic
analysis are used to streamline the cost and span associated with proposal
preparation, evaluation and agreement (Yii-Der et al., 2007). In biodiesel production process, so many factors are
put into consideration for a successful analysis such as availability of raw
materials (Feed stocks) capital, labour, site location, good network, roads for
transportation purpose and availability of energy to power the production plant,
for large scale production of biodiesel to be
favourable, the economic analysis must be made the key deriving force
which also determine reliability of biodiesel as an alternative fuel to
petroleum based fuel, (Yii-Der et al.,
2007). In producing biodiesel, the economic aspect are considered important as
the feedstock are readily available in order to make biodiesel profitable
(Peter, et al., 2010).But it became
obovious that the biodiesel which is more friendly to environment and diesel
engines are more expensive than petrol based fuel as a result of insufficient
feedstock which causes lower rate of production (Peter et al., 2010). A thermo-economic analysis is simply used to
determine the flow of exergy and its associated economic values during operation
(Mei and Göran, 1997). The price changes from inflows and outflows of the
operating units of system, but the average price can be determined only if
there is significant change of inflows and outflows of the operating units
((Mei. and Göran, 1997).. This analysis enhance the comparison of the economic
cost of the exergy losses of the process units of concerns, but it dose not
account for efficiency of a system or the effect of one part of the system to
another part of the system (Mei and Göran, 1997)..
Exergoeconomic analysis is a method of combining exergy
and economic analysis, this method is a tool used in evaluating the cost of
inefficiencies of individual process stream in production of biodiesel,
including the intermediate and final product (Hsuan, 2007). The exergoeconomic
analysis was reviewed by Tsatsaronis. (1993). Systematic methodology for the
evaluation of cost associated with the stream exergy developed by Valero et al. (2010). It has been mostly
reported that exergoeconomic method of analysis have been applied for analysis
of energy conversion system such as power plant and cogeneration system with
few application on chemical processes, the exergoeconomic analysis was for a
typical ethylene process (Hsuan, 2007). Exergy based economic method such as
exergoeconomic, thermoeconomic, exergy based pricing, EXCEM analysis, analysis
based on the ratio of thermodynamic loss to capital cost and the relationship
between exergy and economic was reviewed by Rosen (2010). The eco-efficient
biodiesel production process from waste vegetable oils using alkali catalysed
transesterification process was designed by Sergio et al. (2010). Wilmer et al. (2010)
worked on exergy analysis of biodiesel production from palm oil. Economic
comparison of the four continuous processes using acid and alkali catalysts in
fresh vegetable oils (FVOs) and waste vegetable oils (WVOs) was carried out by
(Zhang et al., 2003). It is evident
that previous works have not investigated the efficiency of biodiesel
production from groundnut oil from thermo-economic and exergetic point of view.However,
this research work will focus on exergetic and economic analysis of biodiesel
production from both fresh and waste groundnut oil using alkali catalysed
transesterification process in order to know which production process is more
efficient from exergetic and economic point of view.
1.1 Problem Statement
Several types of transesterification method of
biodiesel production and process technology have been used to produce biodiesel
either at laboratory or commercial scale by different researchers. Also there
were several attempts to select biodiesel process route based on economic
consideration. In adequate investigation of biodiesel production process from
thermo-economic point of view to establish the most efficient process route to
produce biodiesel at commercial scale constitute the problem of this research.
1.2 Aim and Objectives
The aim of this research work is to use
exergetic-economic analysis as a tool to select the most efficient process
configuration for biodiesel production from groundnut oil using alkali based
catalysed transesterification process. The aim of this research can be achieved
by the following objectives
- Identification
and selection of process configuration for commercial production of
biodiesel. - Simulation
of selected biodiesel production process configurations for data
generation. - Energy
and exergy analysis of the selected process configurations. - Economic
analysis of the selected process configurations. - Comparison
to select the best process configuration.
1.3 Scope of Study
This research work will involve the use of Aspen
Hysys plant software package for simulation of biodiesel production from virgin
and waste groundnut oil using alkali based catalyst with energy, exergy and
economy analysis of the production process, the following are the scope of this
research work:
- Fresh
and waste groundnut oils were considered for the analysis. - Aspen
Hysys plant software version 8.0 was selected for this simulation process - Exergy
and economic analysis were the selected basis for comparison. - Basis:
·
Feed specification: 50
250 tonne/year for both FGO and WGO.
·
Product specification: 99.6
% purity of biodiesel from FGO and WGO.
1.4 Justification of Study
This
research work will be justified as followed:
- To
provide understanding of inefficiencies of biodesel production
configuration and how it can be improved. - To
evaluate data and information generated for biodiesel production process
in order to be used for the development of pilot plant. - To
prove the capability of exergy- economic analysis as a tool for the
selection of efficient process route. - To
provide means of reducing the cost of biodiesel production.
To
provide means of environmental protection