The presentation entitled "ENERGY USE PATTERN IN FLOUR MILL" discussed the energy balance, process of milling, input and output energy in flour milling with calculation formula. Energy is a crucial component in industrial background. In flour mill various operation takes place like transportation, cleaning of grains, milling packaging and storage etc. Which requires amount of energy. A hundred percent conversion of energy into work is not possible but we minimise the losses and efficiency of energy use.
2. INTRODUCTION
Energy is an integral component of a modern economy.
The most important resource to both human beings and industrial activities is energy
and energy consumption was projected to increase by 33 per cent from 2010 to 2030 in
the world. (Saidur et al, 2011).
Energy audit is a systematic study or survey to identify how energy is being used.
Energy consumption pattern must be surveyed, thus providing the base for
determining where to search for significant reductions in usage.
An energy auditor has a job of identifying opportunity for saving energy. target
is to simply identify the areas and processes by which energy is consumed the
most.(Aliu et al, 2018)
Proper analysis of information obtained from an Energy Audit can help make
decisions to reduce energy bills for industries, households and businesses, and
to boost the economy in a sector with great potential for future growth, driving
innovation in the process.
Milling is the process of cleaning, tampering and grinding cereal grains into
flour and other milled grained products. (NAMA)
4. Data analysis
The data required for this study was obtained from a walk through energy audit
method carried out in the plant.
I. Annual electrical, thermal (diesel and gas) and manual energies consumed.
II. Annual production output of the plant.
III. Number of workers in the production of wheat flour per annum.
IV. Motor ratings of machines powered by electricity in the production of wheat
flour per annum.
5. Procedure
From the operation data collected, the following procedures were employed to get
them properly analyzed.
I. The three energy sources: electrical, thermal (diesel and gas) and manual energies
were identified.
II. Annual consumption of the energy sources and their consumption for the eight
unit operations were evaluated to understudy the pattern of energy consumption
III. Percentage breakdown of the total energy consumption was evaluated to estimate
the dominant energy source.
IV. The energy use ratio of the plant per annum was evaluated to establish if energy is
effectively used.
V. Operational data for each unit of operation was determined to identify areas of
wasted energy
VI. Tables and figures showing energy consumption for various energy sources.
6. Energy Model Equations
Energy consumption in the processing plant will be analyzed using the
following:
EVALUATION OF ELECTRICAL ENERGY;
The electrical energy input Ep in kWh was evaluated by multiplying the rated
motor power by the operational time and the motor efficiency which is assumed
to be 80%.
EP = ηpt
where:
Ep is the electrical energy in kWh
P is the motor power in kW
t is the operational time in h
ȵ is the motor efficiency (assumed to be 0.8)
7. EVALUATION OF THERMAL (DIESELAND GAS) ENERGY ;
The thermal energy input Ef was calculated as the quantity of fuel consumed W multiplied
by the corresponding calorific value Cf (lower heating value) of fuel.
Ef = Cf .W
where:
Ef is thermal energy input (J)
Cf is caloric value of fuel (J/L)
W is quantity of fuel (kg)
EVALUATION OF MANUAL ENERGY;
Manual energy input, Em, in kW was estimated based on the maximum continuous energy
consumption rate and conversion efficiency. The physical power output of a normal human
being in the tropical climate is approximately 0.75kW sustained for 8–10 hours’ workday
on the average.
Em=0.75Nt
where:
Em is manual energy input for a male worker (kWh) N is the number of persons involved in
the operation and t is the useful time spent (h).
8. TOTAL ENERGY INPUT;
For each unit operation, the total energy input is given as:
Et=Ep+Ef+Em
ENERGY CONSUMPTION ;
This is the total energy consumed by each motor and generator in the plant. It is
calculated using the formula:
Energy Consumption = Units Wattage x Number of Hours Used.
Ec=Pt
where:
Ec is energy consumption (J)
P is the power ratings for each unit (kW)
t is the operational time (h)
9. TOTAL ENERGY CONTENT (ENERGY OUTPUT) OF FINISHED
PRODUCT;
This is the energy output in a finished product of wheat flour. This is calculated using
the model equation:
E0=Mfp+Ecp
where:
E0 is energy of finished product (J)
MFP is energy content of a unit mass of product (J)
ECP is the mass of finished product (kg)
ENERGY OUTPUT;
The amount of energy used or consumed in a process or system. This energy is
calculated from the equation.
Eo=Ec. η
where:
Eo is the output energy (J)
Ec is the energy consumption and
η is the energy efficiency
10. ENERGY USED RATIO ;
Energy used ratio will be evaluated as:
ER=Eo/Et
where: ER is energy used ratio
Et is total energy input
EO is total energy output
ENERGY PRODUCTIVITY ;
It is used to understudy the energy efficiency of an industry or an economy. This
value is calculated using:
E productivity = total energy consumed (Gj)/ total production (Kg)
PERCENTAGE ENERGY CONSUMPTION ;
This is the energy consumption in percentage. It is calculated using:
𝐸
𝐸 𝑛𝑒𝑟𝑔𝑦 = 𝐸𝑛𝑒𝑟𝑔𝑦 𝑇𝑦𝑝𝑒 𝑇𝑜𝑡𝑎𝑙 𝐸𝑛𝑒𝑟𝑔𝑦 × 100%
12. Conclusion
The energy audit of a wheat flour processing plant in has been carried out.
The study reveals that the energy sources in use are electrical, thermal (diesel and gas) and
manual energies accounting for 25.42%, 73.01%, and 1.57% of total annual energy
consumption, respectively, indicating that the industry uses mainly generating set for electrical
power generation during production.
The milling process accounted for the highest energy consumption (44.39%) of the total
energy input, and 36.17% for the finished product storage process.
The energy analysis performed on unit operations indicated that the roller dryer is the main
source of energy waste, accounting for 44.8% inefficiency.
To curtail the unnecessary energy waste and reduce the cost of energy consumption in the
wheat processing plant, the following are recommended:
I. Perform proper maintenance and control so as to improve energy productivity in the plant.
II. Avenue for minimizing energy loses in the roller dryer should be investigated.
13. REFERENCES:
Christian R. et al, 2019. Energy Audit of a Wheat Processing Plantin Port
Harcourt,Nigeria, EJERS, European Journal of Engineering Research and
Science Vol. 4, No. 1, J.nuary 2019.
Aliu S.A. et al, 2018. Energy audit of a flour mill plant: a case study of
crown flour Mill PLC, Nigerian Research Journal of Engineering and
Environmental Sciences 3(1.) 2018 pp. 345-358.