Model Tertutup Sistem Produksi Mandiri Energi pada Industri Tepung Jagung

A CLOSED MODEL OF PRODUCTION SYSTEM FOR
ENERGY INDEPENDENT IN CORN FLOUR INDUSTRY

ANDREAS ZURIEL

DEPARTEMENT OF AGROINDUSTRIAL TECHNOLOGY
FACULTY OF AGRICULTURAL TECHNOLOGY
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2015

STATEMENT OF ORIGINALITY, INFORMATION SOURCE
AND COPYRIGHT TRANSFER
I state that Skripsi entitled: “A Closed Model of Production System for
Energy Independent in Corn Flour Industry” is my own work assisted by supervisor
and has not been submitted in any form to any collage. Source of information from
published or unpublished works are cited in the text and listed in the references
section. Hereby, I state that the copyright of this paper is transferred to Bogor
Agricultural University.

Bogor, September 2015

Andreas Zuriel
NIM F34110110

ABSTRACT
ANDREAS ZURIEL. A Closed Model of Production System for Energy
Independent in Corn Flour Industry. Supervised by: TAJUDDIN BANTACUT
Corn flour industry uses large amounts of energy to produces corn flour. Energy
needs are still met by nonrenewable and limited energy sources that can affect the
production activities in the future. In addition, production of corn flour produced
waste. A byproduct of corn flour production process can be used as a sustainable
alternative energy. The purpose of this research is to develop a model of the mass
balance and energy industries for the processing of corn flour so as to minimize
energy independent of fossil energy dependence. This research is expected to be a
reference in the industrial development of energy independent corn flour or efficient
energy. Closed system model is created from the simplest to the complex. The
development of this model is made to modify the models based on corn flour
production process. Modification of the model is done to obtain the most suitable
model describing the actual situation of corn flour production process. Modeling
results obtained from corn starch yield of 31% at the level of form 3. Corn cobs and

corn husks from production process can be used as biomass energy by 3869.8 kWh
by way of combustion with FBC Boilers with an efficiency of 68% so that the
industry can be self-sufficient energy cornstarch .
Keywords: Corn flour, closed system, energy self-sufficient industry.
ABSTRAK
ANDREAS ZURIEL. Model Tertutup Sistem Produksi Mandiri Energi pada Industri
Tepung Jagung. Dibimbing oleh: TAJUDDIN BANTACUT
Industri tepung jagung menggunakan energi dalam jumlah yang besar untuk
memproduksi tepung jagung. Pemenuhan kebutuhan energi ini masih dipenuhi oleh
sumber energi yang tidak terbarukan dan terbatas persediaanya sehingga dapat
mempengaruhi kegiatan produksi dikemudian hari. Selain itu, dalam kegiatan
produksi tepung jagung dihasilkan limbah. Hasil samping dari proses produksi
tepung jagung dapat dimanfaatkan sebagai energi alternatif yang berkelanjutan.
Tujuan penelitian ini adalah mengembangkan model kesetimbangan massa dan
energi industri tepung jagung mandiri energi sehingga dapat meminimumkan
ketergantungan terhadap energi fosil. Hasil penelitian ini diharapkan dapat dijadikan
rujukan dalam pengembangan industri tepung jagung yang mandiri energi atau lebih
hemat energi. Model sistem tertutup dibuat mulai dari yang paling sederhana sampai
yang lebih kompleks. Model kesetimbangan massa dilakukan berdasarkan pada
proses produksi tepung jagung. Pengembangan model dilakukan hingga diperoleh

model yang paling sesuai menggambarkan situasi aktual proses produksi tepung
jagung. Dari hasil pemodelan diperoleh rendemen tepung jagung sebesar 31% pada
level 3. Limbah jagung berupa tongkol, dan kulit jagung dapat dimanfaatkan sebagai
biomassa sumber energi sebesar 3869,8 kWh dengan cara pembakaran dengan Boiler
FBC dengan efisiensi sebesar 68% sehingga industri tepung jagung dapat mandiri
energi.
Kata kunci: Tepung jagung, sistem tertutup, industri mandiri energi.

A CLOSED MODEL OF PRODUCTION SYSTEM FOR
ENERGY INDEPENDENT IN CORN FLOUR INDUSTRY

ANDREAS ZURIEL

Skripsi
As partial fulfillment of the requirements for the degree of
Bachelor (Honour) of Agricultural Technology
at
Department of Agroindustrial Technology

DEPARTMENT OF AGROINDUSTRIAL TECHNOLOGY

FACULTY OF AGRICULTURAL ENGINEERING AND TECHNOLOGY
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2015

PREFACE
All the Praise and rejoice to my Lord and Savior Jesus Christ for mercies and
blessings so the author could finish this skripsi on time that has completed very well.
Author also say thanks and appreciate to :
1.
Dr Tajuddin Bantacut as the author’s supervisor for his guidance, support and
motivation until this Skripsi completed.
2.
Juliani as my mom and Hasiholan as my Dad, my twin sister Vrila, and
author’s big family for their pray and support.
3.
Trifosa and Alfrida as my very best friend in college for the support from the
very beginning of my college day in IPB.
4.
All of lecturers and staffs of Agroindustrial Technology Department which

provide excellent facilities and services.
5.
Author’s partner: Mohammad Ryan Pratama, Muhammad Nurdiansyah and
Aryosan Tetuko Haryono who have stood together to carry out this research.
6.
Destiara for helping me in the modeling process.
7.
Author’s classmates of Agroindustrial Technology 48 especially for class of P4
who have stayed together in every situation and condition.
8.
All of Friends in Fellowship Students Commission of PMK IPB.
9.
All of author’s friends include almamater or not and all parties that support
completion of this skripsi.
The Author hopes this skripsi can contribute significantly to the development
of science and technology. Author expects critics and suggestion for further
development of better agriculture.

Bogor, September 2015
Andreas Zuriel

xi

TABLE OF CONTENTS
LIST OF FIGURES

xii

LIST OF TABLES

xii

LIST OF APPENDICES

xii

INTRODUCTION

1

Background

1

Research Objective

2

Scope of Research

2

METHODOLOGY

2

Data Collection

2

System Boundary

2

Model Description

3

Mass Balance

3

Energy Content of By-product

3

Process Flow of Self Sufficient Energy

4

MASS BALANCE MODEL

4

Mass Balance Model Level 1

4

Mass Balance Model Level 2

5

Mass Balance Model Level 3

7

RESULT AND DISCUSSION

13

Mass Balance Model Level 1

14

Mass Balance Model Level 2

14

Mass Balance Model Level 3

15

Energy Self-Sufficient in Corn Flour Industry

17

Closed System Production of Corn Flour Industry

19

CONCLUSION AND RECOMENDATION

20

Conclusion

20

Recommendation

20

REFERNCES

21

BIOGRAPHY

28

xii

1
2
3
4
5
6
7
1
2
3
4
5
6
7
8

LIST OF FIGURES
The Mass Model Balance Level 1
The Mass Model Balance Level 2
The Mass Model Balance Level 3
Result for the implementation of the Mass Balance Model Level 1
Result for the implementation of the Mass Balance Model Level 2
(symbols are shown in Table 2)
Result for the implementation of the Mass Balance Model Level 3
(symbols are shown in Table 4)
Closed system model of corn flour industry
LIST OF TABLES
Type of mechine and energy needs for process 1 ton of corn
Symbols used in Mass Balance Model Level 2
Efficiency values of Mass Balance Model Level 2
Symbols used in Mass Balance Model Level 3
Efficiency values of Mass Balance Model Level 3
Yield of corn flour and corn oil calculation results based on the models
at levels 1 to 3
The energy needs for processing 12 Ton of corn intact
The mass balance energy of the energy-independent in corn flour
industry

5
5
8
14
14
16
19
4
6
7
9
13
17
17
18

A LIST OF APPENDICES

1
2
3

The Mass Balance Model calculations of level II
The Mass Balance Model calculations of level III
Energy Calculation for corn flour energy independent

23
24
26

1

INTRODUCTION
Background
Corn is a strategic commodity for Indonesia because its extensive use as animal
feed (directly or processed), staple food for a large part of population (and potentially
for wider society) snacks, industrial raw materials (starch, sugar, processed food),
and energy (bioethanol). The calorific and nutritional value of corn is good enough to
make the corn industry has great development potential.
Corn is composed of 68.86% of corn seeds, 17.53% of corn husks, and 62% of
corn cobs (Indradewa et al. 2005). Corn that have been removed from its husks,
endosperm, germs and tip cap then milled to produce corn flour (SNI 01-3727-1995).
Corn flour is a semi-finished product of dried corn kernels (Suryawijaya 2009).
Parts of the corn from 40 to 50% of the total weight of intact corn (including
corn cobs and corn husks) was underutilized. Waste produced by this processing
industry makes the industry need to add a waste-processing unit, which is usually
done in end of pipe (Christina et al. 2007). This solution is not effective as the
resulting additional-cost will be more expensive yet the handling result is still not
good.
The corn flour industry consumes considerable energy in the production
process. The corn flour industry with a production capacity of 182 ton/ day requires
electricity by 8,568 kWh/ day (Syanto 2011). Fuel used for the production process is
fossil fuel which belongs to the non-renewable energy sources. The use of nonrenewable fuel may bring a great impact on the corn flour industry when it runs out
of fuel and can not do the production activity any longer.
The problems relating to waste and energy use are the main issues of the corn
flour industry. These problems require the development of new systems that can be a
solution to solve such problems (Christina et al. 2007). It is necessary to use a new
approach in the form of an industrial system which is not seen separated from its
surrounding systems, rather it is seen as an integral part which supports one another
to optimize the material cycle as raw materials to be processed into products (Gamer
1995).
Waste produced by the corn flour industry consists of corn cobs and corn husks
containing lignocellulose forms (with 38.99% of fiber content) with the highest
amount of xylan (12.4%) among the other agricultural waste (Richana et al. 2004).
The content makes the waste produced by the corn flour industry can be used as the
source of energy for corn processing. Therefore, the application of a closed system
can cope with the problems of waste and energy that is encountered by the industry.
Energy generation using corn cobs and corn husks can be utilized by itself in
a closed system, without any energy input outside of the system. Based on the
environmental engineering rules, a closed system is defined as a system which each
input and output flows are known (Davis and Cornwell 2013). This research refers to
the closed system rules. Some useful methods used are the modeling mass balance
and corn cobs and the analysis of corn husks’s potential. The developed closed
system is expected to integrate corn flour production and by-product utilization as an
energy source to produce energy in the corn flour industry.

2

Research Objective
This research was aimed at developing a closed-system model of energy
independent corn flour production. The research objective is met by:
1. Developing a mass balance model of the corn flour industry;
2. Calculating the energy needs of the corn flour industry;
3. Calculating the energy potential of the waste produced by the corn flour industry;
and
4. Developing a closed system model for corn flour industry.

Scope of Research
This research covers the calculations of the mass balance and the energy
balance. The input used in the model was a mass balance consisting of corn husks,
corn fiber, corn cobs and corn kernels. The corn flour industries with capacity of 12
ton of intact corn/day was used as a basis of model. The model to develop the
industrial closed-system consisted of corn-flour models, ranging from the simple to
the complex ones. Presented in different model complexity levels, that is named by
Level 1, 2 and 3. The higher the level of a model, the more complex the model is.

RESEARCH METHODS
Data Collection
The data used in this research consisted of primary data and secondary data.
The primary data were obtained from direct observation of corn production
processes, energy needs and the energy sources used. The secondary data used were
journals, research papers, theses, dissertations, and books.

System Boundary
The corn flour industry has a complex production system because it involves
many factors that are interconnected with one another. The factors input (materials
and energy) are required in the production process as well as output (by-products)
which are generated by such production process are interconnected. These factors
require a comprehensive approach to find the optimal solution to the energy needs.
Therefore, the system approach was used to analyze the flow of the necessary energy
mass, including the potential energy of the by-products generated by the corn-flour
production process.
`

Model Description

3

The mass balance model was developed in accordance with the process flow
which is based on the compartment that describes the actual production process. The
model was developed to determine independent variables as the input and dependent
variables as the output. The model was built using the ratio (coefficient of efficiency)
of the independent variables to the dependent variables based on the principles of
linear equations. Microsoft Excel was used to perform the calculations.
Results of the model calculations were compared with the actual production
process of the corn flour industry. Those results were also used to identify and
calculate the quantity of by-products with the potential of providing a source of
energy to meet the needs of the production process. This model has a higher degree
of accuracy and in accordance with the production of actual processess, it forms a
basis for analyzing the potential energy to develop energy independent production
process.

Mass Balance
The mass balance model was created by identifying compartments which
describe the production process. Later, the model was built by formulating mass
balance equations that connect the input and the output. The mass balance model
was developed from a simple model to complex. The simple model was formed
based on the assumption that the system is a single compartment without any spesific
flow of input and output.
The mass balance equations were solved by formulating a matrix based on the
efficiency factor (the ratio of the variable values) from the secondary data on the
mass flow of the corn flour industry. After identifying the mass balance and the
efficiency of the factor, the value of the efficiency and mass balance equations can be
determined.

Energy Content of By-Product
Based on the mass balance model describing the actual condition of the corn
flour industry, the potential energy of by-products can be calculated using the
following equation:
Potential Energy kCal = Mass kg × Caloric Value kCal/kg

in which, the mass of the by-products is obtained from the calculation model, while
the calorific value is obtained from the literature.

4

Process Flow of Self-Sufficient Energy in Corn Flour Industries
The by-products of corn processing were examined at the utility as the primary
energy source to meet the energy needs of the corn processing industry. The energy
use analysis began with calculating the mass balance through observation of the
input-output system of the mass of the materials. The results were in the forms of byproducts and the potential conversion of the mass into energy. Energy needs were
analyzed based on the classification of the tools (machines) used in the production
process, the calculation of the amount of energy used for the production, and the
available energy sources
The corn processing industry uses electricity to do the production process.
However, the energy needs of the corn processing industry differ from one another,
depending on the process technology employed. The amount of electricity required
by the corn processing industry with a capacity of 12,000 kg of corn per day is
presented in Table 1
.
Table 1 Type of machines and energy needed to process 1 ton of corn
Process
Type of machine
Energy need/ton
Corn husk discharging
Corn husk remover
22 kWh
a
Corn in Cob drying
Tray dryer
10 kWh
Corn seed discharging
Corn seed discharger
22 kWh
b
Corn kernel drying
Flat bed dryer
15 kWh
Corn hulling
Corn huller
40 kWh
c
Corn Milling 1
Multi mill
22 kWh
Corn Milling 2
Disc millc
20 kWh
c
Corn oil extraction
Screw presser
7.5 kWh
Source:

a

Ogechukwu 2012
Balitsereal
c
koeswara 2009

b

THE MASS BALANCE MODELS

The Mass Balance Model Level 1 was a simple model of corn processing. This
model simply identified the number of materials entering and exiting the system in
general. Corn parts which can be processed are corn kernels with a total of 68.86% of
corn intact (Indradewa et al. 2005). Corn processing using the dry milling method
will produce corn flour, from 44.5% (Syanto 2011) to 48.4% (Ryan, 2010; Syanto
2011). At the model of the first level, corn flour was 32.36% of the total corn intact
was obtained.
Mass Balance Model Level 1
The Mass Balance Model Level 1 simply identifies the amount of material
entering and exiting the system generally. Processing corn with dry milling method
will produce corn flour 44.5% (Syanto 2011) to 48.4% (Ryan 2010; Syanto 2011).
At the model level 1 is obtained yield of corn flour 32.36% of the total corn intact.

5

Figure 1. Mass Balance Model Level 1

Note: I = input, O = Output (product), W = Waste
I=O+W
Mass Balance Model Level 2

The Mass Balance Model Level 2 was modified and developed from the
previous model. The model at this level described the process of corn flour
production in a more detailed description than the model level one. The model
divided the processing of corn flour into several sections or compartments. This
model was divided into three main compartments, called by shelling, hulling, and
milling to produce corn flour and two additional compartments, namely extraction
and purification to produce corn oil from the by-products of the corn flour
production. Thus, this model generated efficiency values which were equal to the
number of the mass balance equations (5 values), consisting of one independent
variable (I1) and 10 dependent variables (X1, X2, X3, X4, W1, W2, W3, W4, P1 and P2).
The independent variable was the input with a given value (12 ton of intact corn)
while the dependent variables had different values, depending on their respective
efficiency value. The Mass Balance Model Level 2 is shown in Figure 2.

Figure 2 The Mass Balance Model Level 2

6

Table 2 Symbol used in Mass Balance Model level 2
Input
Output
I1
= Corn intact
P1
= Corn flour
P2
= Refined corn oil
Waste
Internal Flow
W1 = Corn husk, corn cob
X1
= Corn kernel
W2 = Corn dergs
X2
= Hulled corn
W3 = Corn groats
X3
= Germ, tip-cap, pericarp
W4 = Dirt
X4
= Crude corn oil
Mass Balance Equations
Compartment I (Shelling)
Compartment II (Hulling)
Compartment III (Milling)
Compartment IV (Corn oil extraction)
Compartment V (Corn oil refining)

:
:
:
:
:

I1 – X1 – W1
X1 – X2 – X3
X2 – W3 – P1
X 3 – X 4 – W2
X4 – P2– W4

=0
=0
=0
=0
=0

(2.1)
(2.2)
(2.3)
(2.4)
(2.5)

Equation Efficiency:
Shelling Efficiency (E1)

� =

=

�

(2.6)

Before further processing the harvested corn, the shelling process was carried out
previously. The Shelling porcess refers to the process of removing corn kernels from
the corn cobs. The overall result of the corn shelling process will produce corn
kernels by 68.86% of the intact corn (Indradewa et al. 2005). Then E1 is 0.689.

Hulling Efficiency (E2)

� =

=

(2.7)

The corn which had undergone the shelling process was then hulled. It was done to
separate corn seeds from their germs, tip cap and pericarp. The corn milling
generates a result by 70% (Widyanti et al. 2011). Then E2 is 0.7.
Milling Efficiency (E3)

� =

�

=

(2.8)

Corn husking results then going trough the milling process. The corn was milled to
produce corn flour by 68.57% (Widyanti et al. 2011). Then E3 is 0.686.

7

Extraction Efficiency (E4)

=

� =

,

� −

,

�

(2.9)

Germs, tip cap and pericarp from the hulling process contain corn oil. They were
extracted to obtain crude corn oil and such a process generated 4.5% to 5% of crude
corn oil from the extracted materials (Koswara 2009). Then E4 is 0.045.
Refining Efficiency (E5)

� =

�

=

�

�

�

(2.10)

The corn oil resulted from the extraction still contains many impurities. It needs to be
refined to obtain pure corn oil. The corn oil refining process generate 95% of refined
crude corn oil (CRA 2006). Then E5 is 0.95.
Based on equation of efficiency coefficient, the summary of factor efficiency
coefficient can be seen in Table 3. The value of the coefficient of efficiency of
Model Level 2 used to supplement matrix in building a model of level 2 (Appendices
1).
Table 3 Efficiency values of the Mass Balance Model Level 2
Efficiency
Value
E1
0.689
E2
0.7
E3
0.686
E4
0.045
E5
0.95

Mass Balance Model Level 3
The Mass Balance Model Level 3 was modified and developed from the
previous model. This level provided the described process of corn flour production
more specifically than the previous model did. The model consisted of several
compartments which were developed from those in the previous model.
This model generated efficiency values which were equal to the number of the
compartments (fourteen compartments), consisting of five independent variables
(I1,I2,I3,I4,I5) and twenty eight dependent variables (X1, X2, X3, X4, X5, X6, X7, X8, X9,
X10, X11, X12, X13, X14, W1, W2, W3, W4, W5, W6, W7, W8, W9, W10, W11, W12, P1
and P2). The independent variables were consistent variables with a given value (12
ton of intact corn) while the dependent variables had different values, depending on
their respective efficiency value. This model is shown in Figure 3.

Figure 3 The Mass Balance Model Level 3

8

9

Compartment
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
XIII
XIV

I1
I2
I3
I4
I5
W1
W2
W3
W4
W5
W6
W7
W8
W9
W10
W11
W12

Table 4 Symbol used in Mass Balance Level 3
Definition
Corn husk discharging
Corn cob drying
Shelling
Corn kernel drying
Hulling
First milling
Second milling
First extraction
Second extraction
Degumming
Netraliztion
Bleaching
Winteriztion
Deodorization

Input
= Corn intact
= Solvent (Hexan)
= Water
= Alkali
= Bleaching earth
Waste
= Corn husk
= Evaporated water
= Corn cob
= Evaporated water
= Corn groats
= Corn groats
= Corn dregs
= Posphorus
= Dirt
= Dirt
= Wax
= Volatile agent

P1
P2

Output
= Corn flour
= Corn oil

X1
X2
X3
X4
X5
X6
X7
X8
X9
X10
X11
X12
X13
X14

Internal Flow
= Corn without husks
= Dried corn without husk
= Corn kernel
= Dried Corn kernel
= Germ, tip- cap, pericarp
= Corn from hulling process
= Corn after 1st milling
= Crude corn oil
= Husk
= Crude corn oil
= Degummed corn oil
= Neutralized corn oil
= Bleached corn oil
= Winterized corn oil

10

Mass Balance Equations
Compartment 1
Compartment 2
Compartment 3
Compartment 4
Compartment 5
Compartment 6
Compartment 7
Compartment 8
Compartment 9
Compartment 10
Compartment 11
Compartment 12
Compartment 13
Compartment 14

I1 − W1 − X1
X1 − X2 − W2
X2 − X3 − W3
X3 − X4 −W4
X4 − X5 − X6
X6 − X7 − W5
X7 – P 1 − W 6
X5 − X8 − X9
I2 − W7 − X9 + X10
X8 + X10 + I3 − W8 − X11
X11 + I4 − X12 − W9
X12 + I5 − X13 − W10
X13 − X14 − W11
X14 − W12 − P2

:
:
:
:
:
:
:
:
:
:
:
:
:
:

=0
=0
=0
=0
=0
=0
=0
=0
=0
=0
=0
=0
=0
=0

(3.1)
(3.2)
(3.3)
(3.4)
(3.5)
(3.6)
(3.7)
(3.8)
(3.9)
(3.10)
(3.11)
(3.12)
(3.13)
(3.14)

Equation Efficiency
Corn husk discharging efficiency (E1)

� =

� ℎ

=

ℎ

(3.15)

Once the corn had been harvested, it was left for a few moments. Then, the corn
husks were removed. The separation of corn husks obtained corn in cob by 86.4% of
the weight of corn intact (Indradewa et al. 2005). Then E1 is 0.864.
Corn-on-Cob Drying Efficiency (E2)

� =

=

�

� ℎ

ℎ

(3.16)

Corn is generally harvested during the rainy season with heavy rainfall and humidity.
Such a condition makes newly-harvested corn has high moisture content, ranging
from 25 to 35% (Firman et al. 2006). The newly-harvested corn needs to be dried to
reduce its moisture content until 18% (Thahir et al. 1988) or between 17 and 20%
(Wijandi 2003). Corn drying is performed to avoid damage to corn at the time it
undergoes the shelling process (Handerson and Perry 1982). Then E2 is 0.875.
Corn Seeds Discharging Efficiency (E3)

� =

=

�

(3.17)

11

Corn without husks were removed from the cobs. This process made corn oncob into
corn kernels. The corn kernels obtained were equal to 85.2% of the weight of the
corn intact (Indradewa et al. 2005). Then E3 is 0.852.
Corn Kernel Drying Efficiency (E4)

� =

=

�

(3.18)

Corn kernels have moisture content by 17 to 20% (Wijandi 2003). Then, the corn
needs to be dried again until the moisture content ranges from 12 to 14% (Brooker et
al. 1974) and the maximum moisture content is 17% (Firmansyah et al. 2005). The
efficiency value generated from the drying process is equal to 91%. Such a process is
aimed at making corn kernels more durable (Handerson and Perry 1982). Then E4 is
0.91.
Hulling Efficiency (E5)

=

� =

(3.19)

�

Corn hulling refers to the process of corn grinding to separate the germ, tip-cap and
pericarp. The milling process generates an efficiency value by 70% (Widayanti et al.
2011). Then E1 is 0.7.
First Milling Efficiency (E6)

� =

=

ℎ

ℎ

�

(3.20)

The initial corn milling process is done roughly and produces grit by 86%
(Widayanti et al. 2011). Then E6 is 0.86.
Second Milling Efficiency (E7)

� =

�

=

ℎ

(3.21)

�

Corn that has passed the first milling process undergoes the second milling process
and produces corn flour by 87% of the processed materials (Widayanti et al. 2011).
Then E1 is 0.87.
First Extraction Efficiency (E8)

� =

=

,

� −

,

�

�

(3.22)

Corn kernels are composed of germ, tip cap and pericarp obtained from the milling
process and have relatively high oil content. Oil from these sections can be extracted

12

to produce corn oil by means of compression. This extraction by processing the
resulting corn oil obtains 4.4% of the extracted portion using the screw presser
(Koswara 2009). Then E8 is 0.44.
Second Extraction Efficiency (E9)

� =

=

+

�

+

(3.23)

The residual ingredients of the first extraction still contain a small amount of corn
oil. It can be extracted using solvents (hexan). This oil extraction will produce coarse
corn by 1.4% of the total ingredients extracted (Koswara 2009). Then E9 is 0.14.
Degumming Efficiency (E10)

�

=

+

=

+

�+

�

(3.24)

Pure corn oil is obtained from coarse corn oil refining. The first stage of the refining
process is degumming. The degumming process is carried out to remove impurities
in the form of gum using 1 to 3% of hot water from the total oil. It produces oil by
96% of the total crude corn oil (CRA 2006). Then E10 is 0.96.
Neutralization Efficiency (E11)

�

=

+

=

�

��

�+

�

�

(3.25)

.

The second stage of the purification process is neutralization. This purification
process aims to neutralize the corn oil using the alkali treatment, the addition of
alkali is 1% of the total oil. This process will produce corn oil by 97% of the
materials processed (The Asosiation of Corn Sugar Manufacturers 2006). Then E11 is
0.97.
Bleaching Efficiency (E12)

�

=

=

�

��

ℎ

�+

�

ℎ�

ℎ

(3.26)

The corn oil bleaching process is performed using bleaching earth to eliminate the
color of the oil. The refining process will yield corn oil generated by the bleaching
process by 97% of the materials processed (The Asosiation of Corn Sugar
Manufacturers 2006). Then E12 is 0.97.
Winterization Efficiency (E13)

�

=

=

�

��

ℎ

�

�

(3.27)

13

The winterization process is done to separate the wax from the oil content of the
corn. This process will produce winterized corn oil by 98% of the total input
materials (The Asosiation of Corn Sugar Manufacturers 2006). Then E13 is 0.98.
Deodorization Efficiency (E14)

�

=

�

=

�

�

��

�

�

(3.28)

The deodorization process is carried out with the aim of eliminating the smell of the
corn oil. This process is done by heating causing the volatile compounds to
evaporate. This is the final stage of the corn oil refining process. This process will
generate pure corn oil by 98% of the total corn oil processed (The Asosiation of Corn
Sugar Manufacturers 2006). Then E14 is 0.98.
Based on equation of efficiency coefficient, the summary of factor efficiency
coefficient can be seen in Table 5. The value of the coefficient of efficiency of
Model Level 3 used to supplement matrix in building a model of level I3
(Appendices 2).
Table 5 Efficiency values of Mass Balance Model Level 3
Efiiciency
Value
E1
0.864
E2
0.875
E3
0.852
E4
0.91
E5
0.70
E6
0.86
E7
0.87
E8
0.44
E9
0.14
E10
0.96
E11
0.97
E12
0.97
E13
0.98
E14
0.98

RESULTS AND DISCUSSION

The closed system model is intended to describe the actual situation of the corn
flour industry. This closed system model refers to the corn flour production process.
Development of a closed system model for corn flour production was done at three
levels based on the complexity of the model, namely the first-level model, the
second-level model and the third-level model. Of these three models, it had been
determined which model was most suitable for the corn flour production system
based on the levels of efficiency and conservation of energy produced.

14

Mass Balance Level 1
The mass balance model with a basic level of 1 input from 12 ton of corn
intact. From this model, a total of 32.64% of corn flour was produced from corn
shelling and corn milling. The shelling process gained corn kernels as much as
68.86% of the total weight of the corn intact. Dry milling produced corn flour as
much as 48% of the total corn kernels. The mass balance model can not describe the
actual conditions as it only consisted of input corn and the percentage of the corn
flour products was revealed along with the by-products.
The Mass Balance Model Level 1 could not provide full descriptions to
illustrate the actual process taking place in the corn flour industry. The waste
produced was not identified clearly. It will cause difficulties in analyzing energy
potential. For those reasons, it is necessary to modify the first model to describe the
actual corn flour production in a more detailed manner. Meanwhile, the Mass
Balance Model Level 1 is still needed to measure the consistency of the second
model.

Figure 4 Result for the implementation of the Mass Balance Model Level 1

Mass Balance Level 2
The Mass Balance Model Level 2 has 5 compartments (Figure 2) and 5 efficiency
values (Table 4). Thus, it generates a model as shown in Figure 5. For the detailed
implementation and calculation results, please refer to Appendix 1

Figure 5 Result for the implementation of the Mass Balance Model Level 2
(symbol are shown in Table 2)

15

The second-level model used the same basis as the previous model. The
amount of corn flour produced was 32.36%. The corn flour production process
produced corn oil by 0.89% as a by-product of the corn germ. Calculations at the
second level were carried out at each stage of the corn flour processing. However,
this model can not describe the actual process of corn processing as at this level,
calculations were done only for any compartment describing the principal station of
the corn flour processing.

Mass balance of Level 3
The Mass Balance Model Level 3 was developed based on the previous model.
Each compartment was divided into several sections making them more detailed. The
Mass Balance Model Level 3 produced 31% of corn flour and 0.87% of corn oil. The
developed model is shown in Figure 6 as for the calculations, please refer to
Appendix 2.

16

Figure 6 Result for the implementation of the Mass Balance Model Level 3 (symbols are shown in Table 4)

17

Calculations of the Mass Balance Models at Levels 1, 2 and 3 generated
consistent results as shown in Table 3, the model used for the next discussion is the
Mass Balance Model Level 3 because this model is more detailed and provides more
descriptions of the actual conditions relating to corn flour production.
Table 6 Yield of corn flour and corn oil calculation results based on the models
at levels 1 to 3
Product
Result Model
Result Model
Result Model
Level 1
Level 2
Level 3
Corn flour
Corn oil

32.64 %
-

32.36 %
0.89%

31%
0.87%

Based on Table 6, the amount of corn oil is different at each level. However,
the differences are not significant. Those differences exist as at a higher level the
mass flow calculation is more detail than at a lower level so that the calculation is
more specific and results in different values.
Energy Self-Sufficient in Corn Flour Industry
The corn flour industry needs electricity to carry out the production process.
The primary processing activities carried out by the corn flour industry are removing
corn husks, performing the drying process, performing the corn shelling process,
hulling, milling and extracting corn oil. Each process involves the use of machines
which require electricity. The types and specifications of the machines are shown in
Table 1. Based on Table 1, the corn flour industry with a capacity of 12 ton of corn
per day requires 1,177.1 kWh of electricity, the calculation results are shown in
Table 7.
Tabel 7 The energy needs for processing 12 Ton of corn intact
Process
Corn husk disharging
Corn-on-cob drying
Corn shelling
Corn kernel drying
Corn hulling
Corn milling 1
Corn milling 2
Corn oil extraction
Total

Total Material
(Ton)
12
10.4
9.1
7.73
7.03
5
4.3
2.1

Energy
needs(kWh/ton)
22
10
22
15
40
22
20
7.5

Total energy needs
(kWh)
264
104
200.2
115.95
281.2
110
86
15.75
1,177.1

Waste of corn from shelling process are corn husk and corn cob. Corn husk is
outer Corn waste produced from the shelling process consisted of corn husks and
corn cobs. Corn husks are the outer skin of the corn, while corn cobs are a part
wherein are attached the corn kernels. Corn cobs and corn husks have high potential
to be used as a source of renewable energy. There are a number of methods to utilize
corn waste for energy generation. Generally, they are divided into two paths, namely

18

thermochemistry and biochemistry. The thermochemistry paths are combustion,
gasification and pyrolysis while the biochemistry paths are fermentation and
esterification.
Corn cobs and corn husk can be used as biomass for thermal gasification
processes. The calorific value of corn cobs is equal to 13.4 MJ/ kg. With the
carbonization process, the calorific value of corn cobs can be increased into 3,500 to
4,500 kcal/ kg or 14 to 18.9MJ/ kg, while combustion makes the energy content
reach 32 MJ/ kg (Watson 1988 in Prostowo et al. 1998; Mochidzuki et al. 2002).
The use of corn cobs as a gasification material has been very common,
however a number of obstacles are still encountered. One of the most visible
obstacles is the low calorific value and density of the corn cobs. According to Urono
(2010), the combustion process can increase the carbon content and the calorific
value of the corn cob waste. It makes the calorific value of corn cobs increase by
approximately 65% and the carbon content increase by about 67%. The combustion
generate the bound carbon content and the high calorific value at a temperature of
380ºC carbonization by 52.6% and 7,128.38 kcal/ kg, respectively. The low calorific
value and density make the gasification process of corn cobs will very quickly burn
and become unstable so that the gas cannot be utilized optimally and can only be
used by 12%.
Waste in the form of corn cobs and corn husks can be used as alternative fuel.
Corn waste can be processed into ethanol and butanediol through fermentation. This
fermentation process will generate ethanol with an energy value by 122 MJ/ kg and
2,3-butanediol with an energy value by 114 MJ/ kg. (Anon 2002; Lachke 2002).
The thermochemistry paths tend to be chosen in this research. They are easier
to be applied. Thus, thermochemistry through direct combustion is chosen to be
analyzed in this research.
Direct combustion for electricity generation using steam power can be
applied using fluidized bed combustion boilers. It is the proper technology for low
density biomass conversion into energy since it has good mass transfer and heat
transfer characteristics. (Jiang et al. 2003; Loha et al. 2013). FBC also offers a
number of benefits, such as: a compact boiler design, flexibility with the fuel used,
higher combustion efficiency and reduced emissions of noxious pollutants such as
SOx and NOx. The fuel is burnt in these boilers, including coal, washery rejects, and
other agricultural waste (UNEP 2007).
Production of electricity energy uses steam turbine generators with an
efficiency value by 33 to 35% and can be optimalized to 74.13 to 86.40% in the
isentropic condition (Batt and Rajkumar 1999). Steam production using boilers is
heated by fluidized bed combustion. Efficiency of steam production using these
boilers is equal to 68% (Yadav and Singh 2011). Calculations relating to the use of
corn waste through energy independence are shown in Table 8 and Appendix 3.
Table 8 The mass balance energy of the energy-independent in corn flour industry
Type of energy
Value (kWh)
Energy obtained from biomass
3,869
Energy Needs
1,177.1
Energy Surplus
2,692.711

19

Based on calculation above corn flour industry can be energy independent by
applying closed production system utilizing corn waste as energy resource.
The using of corn cob and corn husk as energy resource can reduce fossil fuel
using of corn flous industry. If corn flour energy need is assumed to be fulfilled by
grid so it can reduce coal consumption. Energy produced by PLN comes from coal
with ratio of 2,655 kWh per ton of coal (Sulistyono 2012). If corn flour industries
consumes 1,177.1 kWh per ton of corn so it will consumes 443.1 kg coal per ton of
corn. Thus, corn cob and corn husk will reduce the use of coal.
Closed System Production of Corn Flour Industry
A production system produces by-products in the forms of evaporated water,
corn husks, corn cobs, corn groats and corn dergs. The resulting evaporated water
can be reutilized for the degguming process. By-products such as corn groats and
corn dergs can be used as animal feed. By-products which still contain energy such
as corn husks and corn cobs can be utilized as energy input. The model illustrating
the utilization of by-products from the corn flour industry can be seen in Figure 7

Figure 7 Closed system model of corn flour industry

20

CONCLUSIONS AND RECOMMENDATIONS
Conclusions
Shelling processes produce corn waste such as corn husks and corn cobs that
can be utilized as sources of energy for the corn flour industry. The research
indicates that the corn flour industry can be developed into an energy-independent
industry if it includes its processing activity with the shelling process.
For the corn flour industry with a capacity of 12 ton of corn intact per day, it
produces 1,632 kg of corn husks and 1,298 kg of corn cobs. The by-products can
generate electricity by 3,869.8 kWh per day more than the electricity required for
production that by 1,177.1 kWh. Therefore, this industry can be considered to be
energy surplus industry.
Suggestion
This research is based on dry milling process that is different from wet
milling process. For future research, it will be needed making the wet milling process
model for comparation between the dry and the wet milling process to choose the
best result and application of energy independent.
The energy-independent corn flour industry can also produce water from the
drying process which later can be utilized for the degumming process. The corn flour
industry also produces corn groats and corn dergs which can be used for animal feed.

21

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24

APPENDICES

Appendices 1 The Mass Balance Model calculations of level II

Appendices 2 The Mass Balance Model calculations of level III

25

26

Appendices 2 The Mass Balance Model calculations of level III(Continuation)

27

Appendices 3 Energy calculation for corn flour Energy independent

28

BIOGRAPHY
Author was born in Jakarta at May 5th, 1993 from Couple of
Hasiholan Sitompul and Juliani Djajapranata. He was graduated from
Senior High School 2 Jakarta at 2011. He was accepted as a student of
Agroindustrial Technology, Bogor Agricultural University in the same
year through SNMPTN.
Author joined internal and external organizations in the collage.
He also served as a member of student service commission of IPB
Christian Community in 2011–2015.
He practiced in the field of PT Perkebunan Nusantara VIII in Ciater from
June to August 2014, with the topic of “Mempelajari Proses Produksi dan
Penanganan Limbah Teh di PT Perkebunan Nusantara VIII Ciater”.