Menghitung Efisiensi Hot Oil Heater [PDF]

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1. Menghitung Efisiensi Hot Oil Heater Diketahui



: V hot oil = 800 m3/jam Tin = 278 oC = 551 K Tout = 218 oC = 591 K 𝜌 hot oil = 803 Kg/m3 Cp hot oil = 2,6334 KJ/Kg.K



 Menentukan Massa hot oil yang masuk M hot oil = V hot oil . 𝜌 hot oil = 800 m3/jam . 803 Kg/m3 = 646,640 kg/jam  Menghitung neraca energi Q hot oil = m. Cp. ΔT = 646,640 kg/jam . 2,6334 KJ/Kg.K . (591 K – 551 k) = 68.114.471,04 KJ/Jam  Feed Natural Gas 1 kg/hr NG



= 0,14 MMSCF



2,1 kg/hr NG



= 2,1 MMSCF



2,1 kg/hr NG



= 0,14 MMSCF . 2,1 MMSCF . 6 burner =1,764 MMSCF



1,764 23



= 0,0735 MMSCf = 73.500 SCF/hr



 Energi Natural Gas Q yang dihasilkan NG



= GHV . Feed NG



= 1.016,61 BTU/scf . 73.500 SCF/jam = 74.720.835 BTU/jam = 78,834.564,279 KJ/jam  Efisiensi Hot Oil Ɛ =



=



𝐸𝑛𝑒𝑟𝑔𝑖 𝑦𝑎𝑛𝑔 𝑑𝑖𝑠𝑒𝑟𝑎𝑝 𝐻𝑂 𝐸𝑛𝑒𝑟𝑔𝑖 𝑦𝑎𝑛𝑔 𝑑𝑖ℎ𝑠𝑖𝑙𝑘𝑎𝑛 𝑁𝐺



68.114.471,0.4𝐾𝐽/𝐽𝑎𝑚 78.834.564 𝐾𝐽/𝐽𝐴𝑚



𝑥100 %



𝑥100% = 86,40 %



 Energi yang tidak diserap HO Q yang tidak diserap HO = Q yang dihasilkan NG - Q yang diserap oil = 78.843.654,279 KJ/Jam – 68.114.471,04 = 10.720.183,239 KJ/Jam 2. Menghitung Efiensi Air Preheater (APH)  Diketauhi



: V udara = 31.670.96493 m3/jam Tcin = 35 oC = (308 K) Tcout = 175 oC = 443 K Thin = 393,3 oC = 666,9 K Thout = 200 oC = 473 K Cp udara = 1,01055 KJ/Kg/.K



a) Menghitung untuk udara dingin  Menghitung Densitas Udara 𝜌 udara =



M. ρ RT



=



28,8



Kg Kmol



x 1 atm



0,082 L.atm.K−1 x 375,5 K



= 0,9353 gr/L = 0,9353 Kg/m3



 Menghitung Massa udara yang masuk mudara = Vudara + 𝜌 = 31.670,96493 m3/jam x 0,9353 Kg/m3 = 29.621,8535 Kg/jam  Menghitung Neraca Energi Qudara = m x Cp x ΔT = 29.621,8535 Kg/jam x 1,01055 KJ/Kg/.K x (433 K – 308 K) = 4.041.139,147 KJ/Jam b) Menghitung untuk udara panas (flue gas)  Menghitung Volume Natural Gas Feed NG



= 2.1 Kg



1 Kg



= 0.14 MMSCF



2.1 Kg



= 0.14 MMSCF x 2.1 Kg x 6 burner = 1.764 MMSCF



1.764 MMSCF x



1 24 jam



= 0.0735 MMSCF/jam



 Natural Gas yang masuk



= 0.0735 MMSCF



1 MMSCF



= 11800 m3/jam



Volume NG



=



11800 m3/jam 24



x 0.0735 MMSCF/jam



= 36.1375 m3/jam  Menghitung volume flue gas V gas = V udara + V NG = 31670.96493 m3/jam + 36,1375 m3/jam = 31707.10243 m3/jam



 Menentukan massa flue gas yang masuk m gas = V gas x 𝜌 gas = 31707.10243 m3/jam x 0.62099 kg/m3 = 19689.8 kg/jam  Menghitung Neraca Energi Q gas = m gas x Cp x ΔT = 19689.8 kg/jam x 1.1212375 KJ/Kg.K x (666,9 K – 473 K) = 4280719.078 KJ/jam Efisiensi Air Preheater (APH)



𝜀= =



𝑄 𝑢𝑑𝑎𝑟𝑎 𝑄 𝑔𝑎𝑠



x 100 %



4041139.147 KJ/Jam 4280719.078 KJ/jam



= 94.3 %



x 100 %