Question

a) A Coal from Indonesia which has an ultimate analysis (by mass) as 67.40 % C. 5.31 % H2, 15.11 % O2, 1.44 % N2, 2.36 % S. and 8.38 % ash (non-combustibles) The coal is burned with 30% excess air. Determine: i) The mole fractions of each component of the coal [10 Marks] ii) The combustion equation [14 Marks] iii) The mass of air required per unit mass of coal burned [7 Marks] iv) The total mole number of the product gas [6 Marks] v) The apparent molecular weight (molar mass) of the [6 Marks] product gas Take note that the ash constituent should be neglecte<d b) List 3 possible causes of incomplete combustion[3 Marks] c) State two pollution problems to the environment caused by the exhaust products of the combustion process. 4 Marks]

Answer 1

U e an ultimate analysij as: 2.36xs, and 3-38 a1h The Coaul ij buain b Lis+ 3 possible causes o incomple state two pojlutio problems to the enví.ć on ment caused by the exhaust Ans-Given thaị ÷- a*e l2, 2,32,32 and 29 lcg / kmol Pox Simplicity considet oo Coal , ^hen we Can codite

So, that Clole numbers od the MC : 67. MH2 2 CO2 3 2 2. 1.u4 2-8

n) n½: o.OT. I 4 3 kmol 2 34 3 2 >xy gen, niltogen and sulphu? bxyjen , niteoje? and Sulphu Um: 8. g<9 kmo1

So, that mole Jeactions eath 8. 869 Ye0.6333 8-869 8-869 012 О.0 323 r) 8-8 69

2. 8 8 6 Co2, Co , H20, SOL , and n, The combuton equation moy be C01 + 3-76v1) сові te : C balance balance → o.os3 2 3 + a

m: 6.221 43 i. 3χ 3..70 ath k : o.oo : equation Olt 3.76 V2 unit mass of coal buned is . Mait du el

x32) C0 0082) (o.oo83 Coe (W) The total mole number 영theptoud as 5' 3 6136+ o-22143 Co.oo832xGN) + 3.613Съ28 w eigh1 Cmola mass ) o the

42.o (b) The thtee possible causes tnc ompiete combustion as e a5 )Insusdicienl ime available joz cit and uel i cuixina o insujjicient 3 The supply oy air to the Combustion peocess in insuticienl oltowing ase he two pollutior psoblem to the envitonment which ae caused by the

Acid Rein and Sma Sulphuz dioxide dueing the combuton Sutphu in du uel Due fo the emissior o Caxbo dioxide (Co2) dueing the