MATERIAL AND ENERGY BALANCE We produce acetaldehyde by ...

More documents

Recommendations

Info

The preheater to the distillation column is necessary because the feed plate will becompletely chilled if the feed is not heated. The water stream from condenser c 1 isavailable at 50 0 C and is used in the preheater. If the maximum approach temperaturedifference is 10 0 C, the product stream can at best be heated to 40 0 C. the distillationcolumn pressure is chosen to be 1158 mmHg so that pure acetaldehyde is obtained asliquid product at 40 0 C. In view of this, the stream coming out of the preheater is liquid.Heat balance,At 40 0 C,C p, acetaldehyde = 0.347 kcal / kg 0 C.C p, ethanol = 0.616 kcal / kg 0 C.Let, M w = mass flow rate of cooling water.M w * (50-30) = 433.78 * (40 + 25)* 0.616 + 6308.196*(40+25)*0.347Therefore, M w = 7982.49 kg.Distillation column:In distillation column acetaldehyde condenses at 40 0 C. since vapor pressure data’sof pure gas is not available, it is estimated using Antoine’s equation.ln P = A + B/TWhere, A and B are constants, they can be determined from boiling point data at,Pressures 760 mmHg and 400 mmHg.At 760 mmHg T = 20.2 0 C= 293.2 0 K.400 mmHg T = 4.9 0 C = 277.9 0 K.Therefore, ln 760 = A + B/293.2ln 760 = A + B/277.9On solving above two equations we get,A = 18.29 and B = -3418.2Therefore, ln P = 18.29 – 3418.2/TTherefore at 40 0 C, P = 1586.41 mmHg.D = 6372.56 kg.
x d = 0.99E = 433.78 kg.A = 6308.196 kg.Total feed = F = 6741.976 kg.x f = 0.93W = 369.416 kg.x w = 0.06Assume 99% acetaldehyde recovery in overhead product.Assume x d = 0.99In overhead:Acetaldehyde = 6245.11 kg.Ethanol = 127.45 kg.Total D = 6372.56 kg.In bottom:Acetaldehyde = 63.082 kg.Ethanol = 306.334 kg.Total W = 369.416 kg.F = D + WF * x f = D * x d + W * x wTherefore, x w = F * x f – D * x dW * x wx w = 6741.976 * 0.93 – 6372.56 * 0.99 = 0.06369.416Assume reflux ratio = 0.3
Page 1 and 2: MATERIAL AND ENERGY BALANCEWe produ
Page 3 and 4: From heat balance we have,M steam *
Page 5 and 6: In condenser 1 it is decided to use
Page 7: Liquid ammonia at -33.86 0 C.Vapors

MATERIAL AND ENERGY BALANCE We produce acetaldehyde by ...

Create successful ePaper yourself

Delete template?

Save as template?