Question

Write the balanced stoichiometric combustion equation of dimethyl ether(CH3OCH3) and calculate the adiabatic flame temperature by hand.

Answer 1

tell Combus When nen dimethypothes is burnt in dimethylether is burnt. air the follow reaction 5 the combustion equation for dimethyl ether in air is given as. H₃ C OCH3 + O2 + No 200₂ + 3 H2O + N2 [We consider major component in air. Adiabatic flame temperature : Here we calculate adiabatic flome temperature at constant Pressure from first law of thermodynamies we get. AU 28-w OU Qp - POV (at constant Pressure). again H=U + PV At Conslant Pressure AH-out Port Vap AH=AU + PAV ap-PON+POV AH = 8p under adiabatic condition. Op 20 4H2o. Pooducts = reactants Etreacions (TP) = {Hproducts (IP) By assumption & solvding weget. EH product (T.P) = {n: Ca Hopi + Cei (Tad -TRef) I where, i eth number of component. if one can know the the values of a Hfi, Ce, Tref, then Hel she can easily Calculate the values of Tad.

. Assum Hz eoeltz Assume the following data we proceed to calculate the diabatic flome temperature for the combustion Process. Component Standard ethalpy of Average specificheal formation at 288k - 184100 kJ/kmol - 394000 kJ/kmol 55.396 kJ/kmol - 244500 KJ/kmol 42.99 kJ/kmos 33.0kJ/kmol con НО Basis: 1 kmol of dimethyl ether at Tref=28k at constant Pressure HReachants It Products H seachands -184100 +(1x0) + (140) -18410063/K mo! "products = [ni [ato fit Cp: (Tad-288)] [reef: 1987 = (-394000 + 55.396 (Tad - 298)]*2 + [-244500 + 42.44 (Tad-218)] x 3 + [ 0 + 33.0 (Tad-298)] kl a-1521500 + 271.112 Tad - 80791.376 = -16 02 291.37 6 + 271.112 Tad. this .: - 184100 a-160221.376 +271-112Tad .: Tad = 1602291.376-184100 271.112 25231.02k so the adiabatic flame temperature is 5231002k.