Perhitungan Performance Mesin Turbin Gas | Gas Turbine Engine Performance Calculation

1. PERHITUNGAN KINERJA
TURBIN GAS
Power Plant Tech
Educate and share about Mechanical Engineering

2. Pendahuluan
1. Pengertian kinerja/Performance adalah sesuatu yang dicapai atau prestasi yang diperlihatkan atau kemampuan kerja
suatu peralatan.
2. Performance turbin gas:
 Design
 Off Design
3. Asumsi Perhitungan Performance turbin gas (Siklus Ideal)
 Proses Kompresi dan ekspansi ialah berlangsung secara revessible, isentropik dan adiabatic
 Fluida kerja berperilaku sebagai gas ideal.
 Setiap komponen dianalisis sebagai volume atur pada kondisi tunak.
 Efek energi kinetik dan potensial dapat diabaikan.
 Penuruan atau kenaikan tekanan pada pembakaran di ruang bakar di abaikan
4. Persamaan yang digunakan Hukum Pertama Termodinamika
Q = ΔU + W
 Desain Sistem Termodinamika
 Performance Test Pabrik
 Performance Test Commisioning
 Performance Test Setelah melakukan Maintanace
ataupun repair)
Metode Perhitungan
• Perhitungan Langsung / Metode Input-output
• Perhitungan tidak langsung

3. GT Operation Data
Unit Conversion
Parameters Value Unit
Compressor
Compressor Inlet Temperature 29 C
Compressor Inlet Flow 307302.30 kg/hr
Compressor Inlet Pressure 1.03 kg/cm2
Compressor Discharge Temperature 414.00 C
Compressor Discharge Pressure 1.26 Mpa
Combustion Chamber
Combustion Chamber Pressure 2467 Kpa
Combustion Chamber Temperature 1203.00 C
Fuel Flow Gas 5442.96 kg/hr
LHV 51971.35 kJ/kg
Turbine
Exhaust GT Temperature 597.27 C
Exhaust GT Pressure 0.19 Kpa
Net Load GT 24 MW
Parameters Value Unit Symbols
Compressor
Compressor Inlet Temperature 302.15K T1
Compressor Inlet Flow 85.36kg/s ma
Compressor Inlet Pressure 1.01Bar P1
Compressor Discharge Temperature 687.15K T2
Compressor Discharge Pressure 12.60Bar P2
Combustion Chamber
Combustion Chamber Pressure 24.67Bar P3
Combustion Chamber Temperature 1476.15K T3
Fuel Flow Gas 1.51kg/s mf
LHV 51971.35kJ/kg
Turbine
Exhaust GT Temperature 870.42K T4
Exhaust GT Pressure 1.90Bar P4
Net Load GT 24000Kw Pout

4. mf 1.51kg/s
GHV 51971.35kJ/kg
T3 1476.15K
P3 24.67Bar
T4 870.42K
P4 1.90Bar
T1 302.15K
P1 1.01Bar
ma 85.36kg/s
1
2 3
4
T2 687.15K
P2 12.60Bar
Compressor
Combustion Chamber
Turbine
Generators
Net Load GT 24000 Kw
Compressor Work (Wc)
Efficiency Compressor (ηc)
Efficiency Combustion Chamber
Heat in Combustion Chamber
Turbine Work (Wt)
Efficiency Turbine (ηt)
GT Performance
Shaft Work
Efficiency Thermal
Air fuel Ratio
Back Work Ratio
Cycle Work ratio
Spesific Fuel Comsumption
Hate Rate
Efficiency PLTG

5. Parameters Symbols Value Unit
Pressure Ratio compresor rp 12.47
Pressure Ratio Turbine rp 0.08
Panas spesifik udara (Kompresi) γ 1.40
Panas spesifik udara (Ekspansi) γ 1.30
Temperature Isentropic compressor T2s 621.34K
Temperature Isentropic Turbine T4s 816.94K
Determine the isentropic temperature in the compression and expansion process
Isentropic Compression Isentropic Expansion
Pressure Ratio
rp =
P2
P1
=
12.60 Bar
1.01 Bar
= 12.47 Bar
Isentropic Compression
γ = 1.4 Rasio Panas Spesifik udara (Gas ideal) proses kompresi
γ = 1.3 Rasio Panas Spesifik udara (Gas ideal) proses ekspansi
𝑇2𝑠 = 𝑇1
𝑃2
𝛾−1
𝛾
𝑃1
= 301.15 𝐾 𝑥 12.47 𝐵𝑎𝑟
1.4−1
1.4 = 621.34 K
2s
1
4s
2
3
4
T T2 = 687.15 K
T2s = 621.34 K
S

6. Compressor Inlet Temperature T1 302.15K
Enthalpy Inlet compressor H1 302.35kJ/kg
Compressor Discharge Temperature T2 687.15K
Enthalpy outlet compressor H2 699.47kJ/kg
Temperature Isentropic compressor T2s 621.34K
Enthalpy Isentropic compressor H2s 629.49kJ/kg
Combustion Chamber Temperature T3 1476.15K
Enthalpy Combustion Chamber H3 1486.83kJ/kg
Exhaust GT Temperature T4 870.42K
Enthalpy outlet turbine H4 899.88kJ/kg
Temperature Isentropic Turbine T4s 816.94K
Enthalpy Isentropic turbine H4s 840.606kJ/kg
Determine the enthalpy
• Using the table of properties of ideal gas air
Interpolasi = (H atas – Hbawah) / (Tatas - Tbawah) * (T - Tbawah ) + Hbawah
= (300.19 – 305.22) / (300 – 305) x (302.15 – 305) + 305.22
= 302.35 Kj/kg

7. Wc (actual) = ma · (H2 – H1)
Wc (ideal) = ma · (H2s – H1)
ηC =
𝑇2𝑠 −𝑇1
𝑇2 −𝑇1
=
𝐻2𝑠 −𝐻1
𝐻2 −𝐻1
Compressor
Qin (Ideal) = mf · LHV
Qin (Actual) = ma + mf x H3 - (ma - H2)
Combustion Chamber
Turbine
WT (Actual) = ma + mf · (H3 – H4)
Wt (Ideal) = ma + mf * (GHV - H4S)
ηT =
𝑇3 −𝑇4
𝑇3 −𝑇4𝑠
=
𝐻3 −𝐻4
𝐻3 −𝐻4𝑠
Exhaust
Qout = ma + mf · (H4 – H1)
Symbols Value Unit
Compressor
Compressor Work (Actual) Wca 33898.86Kw
Compressor Work (Ideal) Wc Ideal 27924.73kw
Compressor Losses Wlosses 5974.13kw
Efficiency Compressor
0.82
%
82
Combustion Chamber
Heat in Combustion Chamber (Actual) Qin 69458.33Kw
Heat in Combustion Chamber (Ideal) Qin 78577.212Kw
Combustion Chamber Losses Qlosses 9118.88kw
Efficiency Combustion Chamber
0.88
%
88
Turbine
Turbine Work (Actual) Wta 50990.25kw
Turbine Work (Ideal) Wt ideal 77391.63kw
Efficiency Turbine
0.91
90.8%
Exhaust
Heat out Exhaust 51909.81Kw
CALCULATION

8. Performance Calculation
Symbols Value Unit
Shaft Work Wnett 17091.39kw
Efficiency Thermal ηtr 21.75%
Spesific Fuel Comsumption SFC 0.318kg/kwh
Back Work Ratio BWR 0.66%
Air fuel Ratio AFR 56.5
Efficiency PLTG ηp 0.35%
Hate Rate HR 3.2741kJ/kwh
Cycle Work ratio CWR 34%
Shaft Work (Wnett) Wnett = Turbine work – Compressor work
Specific Fuel Consumption (SFC ) =
3600 𝑥 𝑚𝑓
𝑊𝑛𝑒𝑡𝑡
Back work ratio (BWR) =
𝐶𝑜𝑚𝑝𝑟𝑒𝑠𝑠𝑜𝑟 𝑊𝑜𝑟𝑘
𝑇𝑢𝑟𝑏𝑖𝑛𝑒 𝑊𝑜𝑟𝑘
Air-fuel ratio (AFR) =
𝑚𝑎
𝑚𝑓
Cycle Work ratio (CWR) =
𝑆ℎ𝑎𝑓t 𝑤𝑜𝑟𝑘
𝑇𝑢𝑟𝑏𝑖𝑛𝑒 𝑤𝑜𝑟𝑘
Efficiency GT / Thermal ηt =
𝑊𝑛𝑒𝑡𝑡
𝑚𝑓 𝑥 𝐿𝐻𝑉 𝑎𝑡𝑎𝑢 𝐻𝐻𝑉
Efficiency power generation (ηp) =
𝐷𝑎𝑦𝑎 𝐺𝑒𝑛𝑒𝑟𝑎𝑡𝑜𝑟
𝑄𝑖𝑛
Heat rate =
𝑚𝑓 𝑥 𝐿𝐻𝑉𝑎𝑡𝑎𝑢 𝐻𝐻𝑉
𝐷𝑎𝑦𝑎 𝐺𝑒𝑛𝑒𝑟𝑎𝑡𝑜𝑟

9. 1
2 3
4
T2 687.15K
P2 12.60Bar
T2s 621.34K
H2 699.47kJ/kg
H2s 629.49kJ/kg
Wc Ideal 27924.73kW
Wca 33898.86kW
ηC 82%
T1 302.15K
P1 1.01Bar
ma 85.36kg/s
H1 302.35kJ/kg
mf 1.51kg/s
GHV 51971.35kJ/kg
Qin 78577.21Kw
ηCc 88%
Qin (Actual) 69458.33Kw
Turbine
Compressor
GT Performance
Shaft Work 17091.39kW
Efficiency Thermal 21.75%
Spesific Fuel Comsumption 0.318kg/kWh
Back Work Ratio 0.66%
Air fuel Ratio 56.5
Hate Rate 3.2741kJ/kWh
Cycle Work ratio 0.34%
Efficiency PLTG 0.35 %
Generators
Net Load GT 24000 Kw
T3 1476.15K
P3 24.67Bar
H3 1486.83kJ/kg
Wt Ideal 77391.63kW
Wt 50990.25kW
ηt 90.8%
T4 870.42K
P4 1.90Bar
H4 899.88kJ/kg
T4S 816.9K
H4S 840.61kJ/kg
Qout Ideal 46760.19kW
Qout 51909.81kW
Combustion Chamber
Compressor Losses
5974.13kW
Combustion Chamber Losses
9118.88kW
Turbine Losses
26401.39kW

10. TERIMA KASIH