Gebremariam, Samuel (2009) Energy Audit of Mekanissa Alcohol Factory. Masters thesis, Addis Ababa University.
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PDF (Energy Audit of Mekanissa Alcohol Factory)
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Abstract
Mekanissa Alcohol Factory use furnace oil and electricity as primary source of energy to generate thermal and electric energy to pursue its routine alcohol production. All the thermal energy developed by the boiler is used to evaporate alcohol in the distillery columns. Most of the electricity is used to power different electrically driven systems of the factory. Both the fuel and electricity consumption patterns of the factory are known and are variable from one month to the other. The consumption of fuel was large for month of Jan, 1999 E.C (audit time) which is 649,711.82 litres and the consumption electric energy was large for the month of May, 1998 E.C (audit time) which is 57,765.88 kWh. The unit price of furnace oil and electricity on local market (audit time) are 4.1653 Birr/litre and 0.34 Birr/kWh respectively. The nine energy systems of the factory were inspected to identify energy conservation opportunities (ECOS) and major energy consuming systems of the factory. Out of the nine energy systems, the boiler, distillery columns and pumps, air compressor and their prime movers were found to be major energy consuming systems. To perform the energy audit of these major energy consuming systems, different data were collected by using portable instruments, the instruments installed on major energy systems, nameplate and referring factory log sheet & record book. Using these data pre-energy audit analyses on calorific value of furnace oil, combustion property of the furnace and property of steam were investigated and results were obtained. The NCV of furnace oil used is 39,261.235kJ/kg and the excess air in the boiler was found to be 102%. Standard energy analysis methods were used to perform the energy audit of the boiler, distillery columns, pumps & air compressor and their prime movers. Using these standard methods, the energy balance was conducted to determine the first law efficiency of the boiler and the corresponding Sankey diagram. The result obtained indicated that 1st Law efficiency of the boiler was 74.71% by direct method. This signifies that 25.29% of energy on GCV of the furnace oil was lost. The 1st Law efficiency of the boiler on heat balance method is found to be 76.1%. But the recommended efficiency of a furnace oil fired boiler is about 85% [26]. This signifies that the efficiency of the factory boiler is lower. From the results obtained in the energy audit, the combustion efficiency of furnace is low due to so many factors. One among them is the excess air admitted, which is greater than the recommended value of 15% [4]. The energy audit result also shows the mismatch of steam supply and demand in the factory. The designed capacity of the boiler is to produce a steam of3 , but the factory need is ton / hr @ 8 bar & 175 OC 2 . This shows that the factory boiler is over sized. Among .13ton / hr max@1 bar & 150 OC various energy conservation opportunities (ECOS) identified, replacing the boiler by a proper sized boiler was given the first priority. For replacing the existing boiler with a proper sized, technical and economical analyses were conducted, and the total amount of fuel oil and cost saving per year is 258,957.27 litre and 1,078,634.5 Birr respectively. The energy saving obtained through repairing the water treatment plant and controlling the excess air of the boiler is 7.2% of input energy, with the total fuel cost saving of 560,363.44Birr per year. The simple payback period of implementing these energy conservation opportunities (ECOS) are very short i.e. less than a year.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Mechanical Engineering |
| Subjects: | H Social Sciences > HD Industries. Land use. Labor Q Science > Q Science (General) T Technology > T Technology (General) T Technology > TJ Mechanical engineering and machinery |
| Divisions: | Africana |
| Depositing User: | Andriamparany Edilbert RANOARIVONY |
| Date Deposited: | 20 Nov 2018 08:44 |
| Last Modified: | 20 Nov 2018 08:44 |
| URI: | http://thesisbank.jhia.ac.ke/id/eprint/7597 |
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