Q2. 100 mol/min of an equimolar mixture of n-hexane and n-pentane at 10 °C is fed continuously to a vessel at some press

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Q2 100 Mol Min Of An Equimolar Mixture Of N Hexane And N Pentane At 10 C Is Fed Continuously To A Vessel At Some Press 1 (124.07 KiB) Viewed 12 times

Q2. 100 mol/min of an equimolar mixture of n-hexane and n-pentane at 10 °C is fed continuously to a vessel at some pressure Po, in which the mixture is heated to 70 °C. 50% of the n-pentane in the feed is vaporized (see flow diagram below). (i) (ii) If 80% of the vapour stream is pentane, solve mass balance equation for unknowns Calculate the heat that must be supplied to the mixture per minute. (Neglect changes in Potential energy and Kinetic Energy). (30 Marks)
Initial State Final State Feed in at 10 °C, PO 50 mol/min n-pentane (liq) Yey = 0.8 Process Unit Product out at 70 °C, PO NV Vapour np. mol/min nh, mol/min Liquid NL np. mol/min 50 mol/min n-hexane (liq) Yh.v = 1-ypy = 0.2 N = P+H = 100 mol/min NHL mol/min Heating b =?? Hints: Look up the property table (Table B.1 for (Tb) boiling points of n-hexane and n-pentane along with latent heats etc (Hv), Table B.2 for specific heats of liquid (Cp,L) and vapours (Cp,V) of n-hexane and n-pentane as a function of temperatures, see below) TABLE B.1 Selected Physical Property Data ΔΗ, (Τ.) kJ/mol Compound SG (20/4) Formula ΔΗ, (Τ.) kJ/mol Mol. Wt. (AHM (kJ) 7.(°C) 7.(CY T.(K) Po(atm) (ΔΗ,°) (kJ) n-Pentane CsH2 72.15 0.6318 -129.6 8.393 36.07 25.77 469.80 33.3 -Hexane 86.17 0.659 -95.32 68.74 13.03 28.85 - 173.0(1) -146.4(8) -198.8(1) - 167.2(8) 5079 -3509.5(1) -3536.108) 4163.1(1) -4194.8(8) 29.9 TABLE B.2 Heat Capacities Form 1: C,[kJ/mol.°C)) or (kJ/mol K)] = a + DT + ct? +d3 Form 2: C,[kJ/mol-°C)) or (kJ/mol K)] = a + bT + ct-2 Example: (C)celone (= 0.07196 + (20.10 x 10-5)7- (12.78 x 10-8)+ (34.76 X 10-12)Tº, where T is in °C. Note: The formulas for gases are strictly applicable at pressures low enough for the ideal-gas equation of state to apply. Range Mol. Temp. (Units Compound Formula Wt. State Form Unit a X 100 b x 10 cx 10$ d x 1012 of T) 1-Pentane CH2 72.15 1 1 °C 155.4 43.68 0-36 g 1 °C 114.8 34.09 -18.99 42.26 0-1200 n-Hexane CH4 86.17 1 1 °C 216.3 20-100 8 11 °C 137.44 40.85 -23.92 57.66 0-1200 Specific Heat at Const P for Pentane Liquid (Note that Temperature in Degree Centigrade) Cp(PAL)(T) = 155.4 - 10-3+ 43.68 * 10-5*T Specific Heat at Const P for Pentane Vapour Cp(P1)(T) = 114. 8 + 10-3 + 34.09 - 10-5 * T - 18.99 + 10-8 * 12 +42.26 * 10-12 * 13 Specific Heat at Const P for Hexane Liquid (Note that Temperature in Degree Centigrade) Cp(HL)(T) = 216.3 + 10–3 kJ/(mol.C) Specific Heat at Const P for Hexane Vapour Cp(H,v)(T) = 137.44 * 10^3 + 40.85 + 10-5 + T – 23.92 * 10-8 * T2 +57.66 + 10-12 * 13