NAMA : MAHDI

NIM : 03121003085

SOAL 4.3 EL WAKIL

H2 burn in pure oxygen in chemically correct (stoichiometric). Write the combustion equation and calculate. (a) the mass of products per unit mass of H2, and (b) the lower heatingvalueof H2 if its higher heating value is 61,000 BTU/lbm

Jawab;

Diketahui: HHV= 61000BTU/lbm

H2 + 1/2 O2 H2O

Ditanya (a) Massa H2O /Massa H2

(b) LHV H2 jika HHV 61000 BTU/lbm

Persamaan reaksi

H2 + 1/2 O2 H2O

1mol ½ mol 1mol

Berdasarkan perbandingan koefisien stoliometri reaksi ,maka massa H2O

1mol H2 = 1mol H2O

MassaH 2Mr H 2

=Massa H 20Mr H 2O

Mr H 2OMr H 2

=Massa H 20MassaH 2

182

=Massa H 20Massa H 2

9=Massa H 20Massa H 2

b. HHV 61000 BTU/lbm

data dari Tabel 4.7 buku El wakil halaman 162

Asumsi Air pada fase vapor hf=-5774,6 Btu/lbm

H2 + 1/2 O2 H2O

∆ Hf 25= ∑p

(nMhf )−¿∑r

(nMhf )¿

= (1x18,016x(-5774,6)) – (1x 2,016x 0 + 0.5X32,060X0)

= - 104035,19 Btu/lbmol H2

= −104035,19

2,016 Btu/lbm

= - 51604,75 Btu/lbm

HHV= LHV + ∆ Hf 25

LHV= HHV- ∆ Hf 25

= 61000 BTU/lbm-(- 51604,75) Btu/lbm

= 112604,75 Btu/lbm