Journal of Technology and Policy in Energy and Electric Power Volume 1.
Number 1.
December 2024 https://doi.
org/10.
33322/jtpeep.
v1i1/99 Research Article The Effect of Inlet Water Intake Temperature on the Thermal Efficiency of Timor 1 Coal-Fired Power Plant .
x50 MW) Adiartha Prihananto1* 1 PT PLN (Perser.
UIP Nusa Tenggara * Corresponding author: Adiartha Prihananto, padi.
prihananto@gmail.
CITATION
Author Name.
Article title.
Journal of Technology and Policy in Energy and Electric Power.
1:1.
https://doi.
org/10.
33322/jtpeep.
ARTICLE INFO
Received April 24, 2024
Accepted December 22, 2024
Available online December 22, 2024
COPYRIGHT
Copyright A 2024 by author.
Journal of Technology and Policy in Energy and Electric Power is published by PLN PUSLITBANG Publisher.
LLC.
This work is licensed under the Creative Commons Attribution (CC BY) license.
https://creativecommons.
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Abstract: In a thermal power plant, evaluating the performance of plant can be seen from the thermal efficiency value.
Thermal efficiency is the percentage of heat energy entering the system that is actually converted into electrical energy.
One way to increase the thermal efficiency of the plant is to reduce the temperature of the cooling water at the water intake inlet.
From the research results, a graph shows the relationship between the increase in inlet water intake temperature from 30EE - 33EE to the condenser heat transfer rate, condenser pressure, and thermal efficiency of power plant.
From the results of the calculations carried out, it was found that an increase in the inlet water intake temperature of PLTU Timor 1 .
x50 MW) from 30EE-33C, caused a decrease in the heat transfer rate in the condenser from 81,875 kJ/s Ae 81,873kJ/s, causing an increase in condenser pressure from 0, 0744 bar Ae 0.
0872 bar and causes a decrease in thermal efficiency from 43.
62% Ae 43.
it can be said that the higher inlet water intake temperature, the lower the thermal efficiency of power plant.
Lowering thermal efficiency from 62% Ae 43.
23% will cause an increase in Levelized Generating Cost Value (LGCV) from IDR 1,284/kWh Ae 1,302/kWh.
If LGCV multiplied by the annual kWh production, every 1EE increase in water intake inlet temperature will increase production costs by 5 billion rupiah per year.
Keywords: thermal efficiency, water intake, cooling temperature, condenser pressure Introduction PLTU Timor 1 .
x50 MW) is one of the power plant projects under the 35,000 MW program, which, according to the RUPTL (Electricity Supply Business Pla.
2021-2030, is targeted to achieve COD (Commercial Operation Dat.
PT PLN
UIP Nusa Tenggara, as the project owner, faced challenges in the construction of the Sea Water Intake (SWI) pipe, where, as of August 2022, the physical progress showed a deviation of 30.
The initial intake design used RCCP (Reinforced Concrete Steel Cylinder Pip.
with a length of 565 m extending from the SWI pond.
However, the contractor proposed a design modification to shorten the intake pipe from STA 565 to STA 320 to avoid an excessively long excavation in the offshore area.
This adjustment affected the thermal dispersion of the PLTU Timor 1 outfall, leading to an increase in the inlet water intake temperature.
Thermal dispersion studies revealed that the maximum temperature at the inlet water intake of PLTU Timor 1 .
x50 MW) rose from the initial design of 30EE to 31.
48EE due to the shortening of the intake pipe from STA 565 to STA 320.
The rise in inlet water intake temperature is expected Journal of Technology and Policy in Energy and Electric Power Volume 1.
Number 1.
December 2024 https://doi.
org/10.
33322/jtpeep.
v1i1/99 to reduce the heat transfer rate and condenser vacuum, ultimately lowering the thermal efficiency of PLTU Timor 1 .
x50 MW).
Research by Syed Haider Ali in 2014 indicated that an increase in water intake temperature from 12EE to 42EE resulted in a condenser pressure rise from 0.
10 bar to 0.
48 bar.
This pressure increase caused a decrease in the thermal efficiency of the power plant from 36% to 34.
Similarly, a study by Gamal Yassin and Abdualrazzaq in 2021 on a 300 MW capacity power plant in West Doha simulated cooling water temperature variations between 25EE and 36EE.
Their findings showed that an increase in cooling water temperature from 25EE to 36EE resulted in a condenser pressure rise from 0.
06 bar to 0.
1 bar.
Based on the findings above, an analysis of the thermal efficiency of PLTU Timor 1 .
x50 MW) is necessary to evaluate the impact of changes in inlet water intake temperature from 30EE to 33EE.
Materials and methods Research Design In general, the stages of this research are carried out by identifying the problem of the influence of inlet water intake temperature on the thermal efficiency of PLTU Timor 1 .
x50 MW), followed by collecting data on the Heat & Mass Balance at 100% TMCR, condenser and CWP pump datasheets, and boiler datasheets.
Figure 1.
Process Flow Diagram PLTU Timor 1 .
x50 MW) Data Calculation The data calculation begins with the following steps: calculating the heat transfer rate in the condenser, determining the steam temperature entering the condenser, calculating the heat & mass balance and turbine work from the results of the cycle tempo simulation for each variation of inlet water intake temperature .
EE - 33EE), and calculating the thermal efficiency for each variation of inlet water intake temperature .
EE - 33EE).
Equation for Heat Transfer Rate in the Condenser The basic principle of a condenser's operation is the First Law of Thermodynamics, where the heat transfer rate on the hot side is equal to the heat transfer rate on the cooling water side.
ycEN = ycoNyca yaycyyca .
cNyca,ycuycyc Oe ycNyca,ycnycu ) .
Description:
Journal of Technology and Policy in Energy and Electric Power Volume 1.
Number 1.
December 2024 https://doi.
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v1i1/99 ycoNyca = ycoycaycyc yceycoycuyc ycycaycyce .
yaycyyca = Spesific heat (J/kgEE) ycNyca,ycuycyc = ycCycycycoyceyc ycyceycoycyyceycycaycycycyce (EE) ycNyca,ycuycyc = yaycuycoyceyc ycyceycoycyyceycycaycycycyce (EE) ycEN = ycO yayc OI ycNyco .
Description:
ycO = ycCycyceycycaycoyco Eayceycayc ycycycaycuycyceyceyc ycaycuyceyceyceycnycaycnyceycuyc .
cO/yco2 ) yaNyc = ycIycycyceycaycayce ycaycyceyca ycuyce ycaycuycuyccyceycuycyceyc ycyycnycyyceyc .
co2 ) ycNyco = ycNyceycoycyyceycycaycycycyce yccycnyceyceyceycyceycuycayce ycayceycycyceyceycu ycycycu yceycoycycnyccyc(EE) Equation for Steam Temperature at the Condenser Outlet The temperature difference between the steam and the cooling water is relatively higher at the condenser inlet and decreases exponentially toward the condenser outlet.
The cooling water temperature will never exceed the temperature of the hot fluid .
ondensed stea.
, regardless of the cooling time.
Therefore, the Log Mean Temperature Difference (LMTD) equation is suitable for analyzing heat transfer in the condenser.
Here.
OI ycN1 dan OI ycN2 represent the temperature differences between the two fluids at different points in the condenser.
Figure 2.
Heat Transfer Diagram of the Condenser OIycN OeOIycN OI ycNycoyco = ln(OI 1ycN /OI ycN2 ) .
Turbine Work Equation Turbine work is greatly influenced by the magnitude of the heat drop.
If the enthalpy of the steam leaving the turbine to the condenser decreases, the power generated by the turbine will The enthalpy of the steam exiting the turbine is influenced by the isentropic efficiency.
Under ideal conditions, the entropy of the steam entering the turbine is the same as the entropy of the steam leaving the turbine.
ycOycNycycycaycnycu = .
co1 ycu Ea1 ) - .
co2 ycu Ea2 ) - .
co3 ycu Ea3 ) - .
co4 ycu Ea4 ) - .
co5 ycu Ea5 ) - .
co6 ycu Ea6 ) .
co7 ycu Ea7 ) .
Description :
ycOycNycycycaycnycu =Turbine Work .
J) Ea4 =Enthalpy of steam entering yaycEya 1 .
yco1 =Steam flow rate entering the turbine yco5 =Steam flow rate entering the Deaerator .
Ea1 =Enthalpy of steam entering the turbine Ea5 =Enthalpy of steam entering the .
Deaerator .
Journal of Technology and Policy in Energy and Electric Power Volume 1.
Number 1.
December 2024 https://doi.
org/10.
33322/jtpeep.
v1i1/99 yco2 =Steam flow rate entering the condenser.
Ea2 =Enthalpy of steam entering the condenser .
yco3 =Steam flow rate entering HPH 2 .
Ea3 = yaycuycycaycoycyycn ycycaycy ycoycaycycyco yaycEya 2 .
yco4 = ycIycyceycayco yceycoycuyc ycycaycyce yceycuycyceycycnycuyci yaycEya 1 .
yco6 =Steam flow rate entering yaycEya 2 .
Ea6 =Enthalpy of steam entering LPH 2 .
yco7 = yaycaycyc ycycaycy ycoycaycycyco yaycEya 1 .
Ea7 =Steam flow rate entering LPH 1 .
Thermal Efficiency Equation The thermal efficiency of a power plant is the ratio of the work produced by the turbine to the heat absorbed from the coal fuel.
ycOyayceyceycc ycyycycoycy = .
co1 ycu Ea1 ) - .
co2 ycu Ea2 ) .
ycOycaycuycuyccyceycuycycayc ycyycycoycy = .
co1 ycu Ea1 ) - .
co2 ycu Ea.
ycEycaycuycnycoyceyc = yco1 (Ea1 ycu Ea15 ) .
yayceycnycycnyceycuycycn ycNEayceycycoycayco = ycycycycycaycnycu Oeycycyycuycoycyyca ycEycaycuycnycoyceyc .
Description:
ycOycNycycycaycnycu = ycNycycycaycnycuyce ycOycuycyco .
J) ycOyayceyceycc ycyycycoycy = ycOycuycyco ycuyce yaAycuycnycoyceyc yayceyceycc ycEycycoycy .
ycOycaycuycuyccyceycuycycayc ycyycycoycy = ycOycuycyco ycuyce yaycuycuyccyceycuycycaycyce ycEycycoycy .
ycEycaycuycnycoyceyc = yayceycayc ycnycuycyycyc ycycu ycEayce ycaycuycnycoyceyc .
Plant Heat Rate Equation In performance calculations for power plants, parameters from the boiler, turbine, and generator sides are involved.
The value of the plant heat rate provides an indication of the overall efficiency of a power plant.
The plant heat rate calculation can be determined using the following formula (ASME PTC 4, 2.
ycNycycycaycnycu Eayceycayc ycycaycyce yaycEyaycI = yayceyceycnycaycnyceycuycayc ycaycuycnycoyceyc .
ycAycEyaycI = yaycEyaycI 1Oe( yaycycu ycEycuycyceyc yaycycuycyc ycCycycycyycyc .
Levelized Cost of Electricity (LCOE) Equation yayaycCya = ycAycEycO ycuyce ycNycuycycayco yaycuycyc ycCycyceyc yaycnyceyceycycnycoyce .
ycAycEycO ycuyce yaycoyceycaycycycnycaycayco yaycuyceycyciyc ycEycycuyccycycayceycc ycCycyceyc yaycnyceyceycycnycoyce .
aycuycoycy yayc yaycuycoycy yaAyc yaycuycoycy yayc ) .
yc Oc yayaycCya = yayc .
yc Oc .
Description Component A: Initial Investment Cost (Cape.
(IDR) Component B&D: Maintenance.
Operational (O&M), and Consumable Costs (IDR) Component C: Fuel Cost (IDR) E: Electrical Energy Produced .
t: Year t .
r: Discount Rate (%) Journal of Technology and Policy in Energy and Electric Power Volume 1.
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v1i1/99 Results and discussion Heat & Mass Balance Modeling with Cycle Tempo Figure 3.
Original Heat Balance Diagram 100% TMCR of PLTU Timor 1 .
x50 MW) Based on the thermal dispersion study results, the scenario of modifying the water intake pipe design by shortening the pipe from STA 565 to STA 320 leads to an increase in the water intake temperature from 30EE to 33EE.
The results from the simulation at 100% TMCR will be used to calculate the thermal efficiency of the power plant.
These results will then be simulated with variations in water intake temperature from 30EE to 33EE.
The parameters kept constant in the Heat Balance simulation with variations in inlet water intake temperature from 30EE to 33EE are as follows:
Temperature difference between cooling water inlet and outlet of the condenser: 7EE Mass flow of Circulating Water Pump (CWP): 2.
799 kg/s Constant Auxiliary Power: 6.
377 kW Analysis of Turbine Outlet Pressure and Temperature The heat transfer rate in the condenser is calculated using equation 2.
2, and the logarithmic temperature difference (OI ycNycoyco ) is calculated using equation 2.
Table 1.
Data from Turbine Outlet Pressure and Temperature Calculation Temperatur Water Intake In : 30 Out : 37 In : 31 Out : 38 yeaNyeE J/.
J/kgEE) 4,1788 40,160 0,0744 4,1788 41,159 0,0785 ycya
(EE)
yec yeUyeayeayeIyeIyeayeiyeayee .
Journal of Technology and Policy in Energy and Electric Power Volume 1.
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v1i1/99 In : 32
Out : 39
In : 33
Out : 40
4,1787
42,159
0,0828
4,1787
43,159
0,0872
Analysis of Mass Balance and Turbine Work with Inlet Water Intake Temperature Variations of 30EE - 33EE Water intake inlet temperature 31EE:
Figure 4.
Heat & Mass Balance Modeling of Water Intake Inlet Temperature 31EE with Cycle Tempo Water intake inlet temperature 32EE:
Figure 5.
Heat & Mass Balance Modeling of Water Intake Inlet Temperature 32EE with Cycle Tempo Journal of Technology and Policy in Energy and Electric Power Volume 1.
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v1i1/99 Inlet water intake temperature 33EE:
Figure 6.
Heat & Mass Balance Modeling of Water Intake Inlet Temperature 33EE with Cycle Tempo Turbine Working Table 2.
Data on the results of generating thermal efficiency calculations Temperatur
(EE)
In : 30 Out : 37 In : 31 Out : 38 In : 32 Out : 39 In : 33 Out : 40 Steam Flow .
Boiler .
W) .
W) 939,46 ycyeeyeayeiyei ycyenyeiyecyenyei ycyeIyeayeIyeeyeCyeiyeayee .
W) Plant Efficiency (%) 62,076 938,76 43,48 934,97 43,36 932,29 42,23 ycyeiyenyeeyeEyeOyea ycyecyeayeayecyeC .
W) 61,927 61,781 61,635 43,62 Levelized Generating Cost Value Analysis Plant Heat Rate Table 3.
Data from Net Plant Heat Rate Calculation Results Temperatur Steam yaIyayayaya yaayayayayaya Turbine Flow Heat Rate yaIyayayayayaoyayaya Cal/kW.
(EE) .
W) In : 30
62,076
983,32
Out : 37
In : 31
61,927
989,26
Out : 38
In : 32
61,781
995,24
Out : 39
In : 33
61,635
001,28
Out : 40 Levelized Cost of Electricity (LCOE) GPHR .
Cal/kW.
Aux Power .
W) NPHR .
Cal/kw.
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v1i1/99 Table 4.
Data from LCOE calculation results Temperatur
(EE)
In : 30
Out : 37
In : 31
Out : 38
In : 32
Out : 39
In : 33
Out : 40
yasyaya yaayayayayaya
(MW)
63,000
NPHR
LCOE
Cal/kW.
(Rp/kw.
62,661 62,326 61,991 Analysis of Calculation Data Calculation analysis of condenser heat transfer rate and condenser pressure Figure 7.
Comparison graph of water intake inlet temperature against heat transfer rate and condenser Analysis of Plant Thermal Efficiency Calculations Net Plant Heat Rate
Efisiensi Thermal
43,62
43,48
43,36
43,23
Efisiensi Thermal (%) Net Plant Heat Rate .
Cal/k.
Temperatur Inlet Water Intake (OC) Figure 8.
Comparison graph of water intake inlet temperature on NPHR and generator thermal efficiency Journal of Technology and Policy in Energy and Electric Power Volume 1.
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v1i1/99 Discussion A comparison of the simulation results with the operational parameters at 100% TMCR load is needed to compare the thermal efficiency of the PLTU Timor 1 .
x50 MW) cycle from the simulation results with actual operation.
The construction of a breakwater as a thermal barrier between the inlet water intake and the water outfall is necessary to prevent an increase in the inlet water intake temperature due to the redesign of the water intake pipe, thus maintaining the thermal efficiency at 43.
62% as per the original design.
Conclusion Based on the analysis of the effect of the increase in the inlet water intake temperature of PLTU Timor 1 .
x50 MW) from 30EE to 33EE, there is a decrease in the heat transfer rate at the condenser from 81.
875 kJ/s to 81.
873 kJ/s.
Based on the analysis of the effect of the increase in the inlet water intake temperature of PLTU Timor 1 .
x50 MW) from 30EE to 33EE, there is an increase in the condenser pressure from 0.
0744 bar to 0.
0872 bar and an increase in the turbine exhaust steam temperature from 40.
16EE to 43.
15EE.
Based on the analysis of the effect of the increase in the inlet water intake temperature of PLTU Timor 1 .
x50 MW) from 30EE to 33EE, there is a decrease in thermal efficiency 62% to 43.
Based on the analysis of the effect of the increase in the inlet water intake temperature of PLTU Timor 1 .
x50 MW) from 30EE to 33EE, there is an increase in Net Plant Heat Rate (NPHR) from 2,611 kCal/kWh to 2,640 kCal/kWh and an increase in Levelized Cost of Electricity (LCOE) from Rp 1,284/kWh to Rp 1,302/kWh.
References