Question

1. A thermoelectric steam generation plant operates on a Rankine cycle with reheating and two boiler feed water heaters, one open and one closed. Steam enters the high pressure turbine at P8 and 500 ° C and the low pressure turbine at P10 and 500 ° C. The condenser pressure is 40 kPa. Steam is drawn from the turbine at a pressure P11 for the closed feed water heater and at a pressure P12 for the open feed water heater. In the closed heater, the feed water is heated to the saturation temperature of the extracted steam, this condensate is removed as a saturated liquid, it is throttled and goes to the open feed water heater. The isentropic efficiencies of the equipment that have this efficiency are listed in a later table.
to. Determine the fractions of steam drawn from the turbine to the feedwater heaters.
b. Determine the thermal efficiency and heat rate of the
power. ̇
c. Determine the mass flow required for a power delivery
net of ?net.
d. Show the actual and theoretical cycle on a T-s diagram with respect to the saturation lines.

Variable		DATA
P8		16 MPa
P10		2.5 MPa
P11		0.59 MPa
P12		0.1 MPa
Wnet		12 MW
Isentropic efficiency of turbines		90 %
Isentropic efficiency of the pumps		85 %

Answer 1

son 16 13 s S8 = 6.3046 ks Isk A+ table ; los lask states : ( P8 = 16 MPa Tg = 500°c) from superheated hg = 3297.3 kJ reg point-a: (Pg 2.5 MRa S8=Sg = 6.3046 from suporteated table ; hg = 2826.42 AH iso = 7.3254 kJ lok Isk - state 10: (Pio = 2.5Mira, to - 500°c) from superheated table; hio = 3462. I lej staten: (Pie -0.59M129 Si=8,0 = 7.3254 16) from superheated Teg stater (1=512) 7.3254 table ; ha=3032.5 |_) lok Stoimna & a Stel 0.12 Siz 7.3254 = 7.3254 1.3028 424 6.0561 Ooggy 242 heslo, +42 0.1 MPa holol his = I Mira 417.50 +0.9944 2257.4 2662.4 ko pg

state 13 : ( Sio = S13 = 7.3254 10) ISK S13= Solu + Xp3 Stela d10 ore yolons 1.0261 + 1438 6.6429 7.3254 ņ 43 = 0.948 as hisluonna his - htu yo rana 0.5484 2318.4 317.62 + le) 25761 la day 2-0) water/steam tasle, statel ( P = 401426 from h = 317.62 la) saturated state 2 : (harhi) res (P2P) 0.001x (100-40) ha - 317.62 Kog 317.68 - rey State 3: (p=0.1 Mpe x=0) from saturated waterf steam table; hz = 417.50 Staten : (hy-ho) = us ( 1600-100) = hy - 417.5 = 0.00lx (1600 - roo) - hy= 433.4 leslieg state 6 : ( P6 = 0.59 MPa x=o) from Saforated water/ steam tasle ; ho = 667.65 K log state 7 : hq=ho = 667.65 16.)lig 909). & 854, Also given Mr = efficiency of of fossine & pump are hg-ha ng - ha 3297.3- há - 0.90 3297.3 -28 26.42 W ha 2873.51 leg

hi-his hii -h12 1 = nr = histhis hiz-his hionhill hoorhon 3462.7 hi B462-7 - 3025.5 3032.5-hin 2662.4-his 0.9 0.9 => 0.9 3028.5-2662.4 2662.4-2576-1 m2 = 2699.41 1C) his = 2530.7314 19 han le hay 3075.52 Again, hy-ho mp mp 0.85 = = hqchi hathi = 0.8 317.68-317.62 ha - 317.62 ha 1) 317.65 lg hu-ho 433.4–412.5 hu - 467.5 - hu = 436.2 te\ له۱ (P = 0.59 M129 state 5 : Tsar - 157.92°C hs - 666.79 k) log P=0.59 Mira Tsad=157.900 ; At for closed feed water heater balance Now, Energy 1. hu tahu 1.hs + Y. he - hs-hy = 666.79-43314 y (mu-ho) . = 0.0987 ks/ 66 6.29-433.4 3032.5-667.65 Energy balance for open feed water heater Z. hiz + 11-4-2) h₂ I y ha = 1.43 -> Zx2662.4 + 11-010987-z) x 317.68 + 10.0984x 667.65 - 1x417.5 010278 lsls Z - Mass flow rate through condenser 1-4-2 0.0278 - 1-0.0987 -0.one 0.873

Pusline work (Wr) Wg ling-ha) + 1. (no-hi) + (1-4) (hip-his) + (1-4-2). (hig hin) - 13297.3 – 2873.51) + 34627 - 3095.52) + Ci-0.0987) × (3032-5-2699.41) +11-0.8987-0·0228) * ( 2662.4 - 2510.73) 1226.13 kelias yumba work (ap) : wp- (1-4-2) (hâ chil+ Chá_h) (1-0.0989 – 0.0278) (317.69-317.62) + (436:2-417.5) 18.76 las/log Heat supplied (6) as a 1.(he-hs) + lho-ho) - (3297.3 - 667.25)+ (3462-7 - 2826.42) 3230.79 1. lig thesonal efficiency 1226.13 - 18.76 = 0.3737 We wp nth 3230.79 ar 37.37 7.394) 12 MW Given, Whet = Whet im (po wp) w (1226.13 -1876) 9.938 108/ 2 x 103 m น 1