TY  - JOUR
TI  - Theoretical Analysis of a Lignite-Fired Power Plant with Pre-Drying System in Terms of Energy Efficiency and Economy
AB  - The coals with different initial moisture content to be used in the theoretical analysis were tested according to the related teststandards and the results were used in the analysis. In the designed system, waste heat in the flue gas is used as the heat source.The fresh air is heated for drying in the shell-tube heat exchanger by means of flue gas. In fluidized bed dryers, the moisture of thecoal was reduced by contacting the raw coal with the drying air. Due to the high initial moisture of the coals used in the theoreticalanalysis, the pre-drying degree could be at most 0.14 in order that the boiler feeding rate be the same as in the power plant feedingrate without pre-drying system. The system theoretically does not conform to the design parameters and the boiler feed rate is lessthan the flow rate of power plant without pre-drying system when the pre-drying degree is greater than 0.14. The pre-drying systemhad ten small capacity dryers working simultaneously to ensure the continuity of the boiler feed. In the study, the theoreticalanalysis was performed, and thermal performance of the power plant were formulized and graphically presented according to predrying degree. Thanks to the pre-drying system, owing to the decrease in the moisture content of the coal, a reduction in the fluegas flow rate and the amount of energy required to evaporate the moisture are realized. As a result, there was a decrease in theboiler losses and an increase in the efficiency of the boiler. The increase in boiler efficiency was 10.74% when coal 1 had beenused and it was 7.92% when coal 2 had been used. Since the coals are dried in the same drying system under the same conditions,the moisture of coal 1 decreases more, thus the losses of the boiler decrease more. Due to the increase in the lower heating valueand in the boiler efficiency, the efficiency of the power plant with pre-drying could increase by 3.04-4.34%. The coal pre-driedpower plant had far more economic performance than a power plant without pre-drying system, since more electricity would beobtained thanks to the increase in efficiency of the plant. The redemption period of the system was determined as 2 years with coal1 and it was determined as 3 years with coal 2. After the payback periods, the system makes a net profit and brings in an averageof 55 million TL extra income per year. In addition, it was observed that when the degree of pre-drying was decreased, economicefficiency of the system also decreased. It is aimed that the study will provide principles of energy efficiency improvement in coalfired power plants with pre-drying system and will guide people who wants to do similar studies.
AU  - Yatarkalkmaz, Mehmet Mustafa
DO  - 10.2339/politeknik.670890
PY  - 2021
JO  - Politeknik Dergisi
VL  - 24
IS  - 1
SN  - 1302-0900
SP  - 205
EP  - 217
DB  - TRDizin
UR  - http://search/yayin/detay/419132
ER  -