Chemical Engineering Answers

One thousand kilograms per hour of a mixture of benzene (B) and toluene (T) that contains 60 % benzene by mass are separated by distillation into two fractions. The mass flow rate of benzene in the top stream is 470 kg B/h, and that of toluene in the bottom stream is 350 kg T/h. The operation is at steady state. a. Draw and label the flowchart of the process. b. Write balances on benzene and toluene to calculate the unknown component flow rates in the output streams.

Hydrogen can be produced using a process called coal gasification. It is desired to supply nearly pure oxygen to this process. Oxygen is separated from nitrogen out of the air (79 mol% nitrogen and 21 mol% oxygen) via a process known as cryogenic distillation. A cryogenic distillation unit has a feed of 2000 kgmol/hr air. The top stream has 1400 kgmol/hr nitrogen and the bottom stream has 320 kgmol/hr oxygen. a. Draw and label the flowchart of the process in block diagram. b. Write balances on the oxygen and nitrogen to determine the unknown component molar flow rates.

the distillation column of an Acetaldehyde plant has the following process

conditions temperature, 60 0C; gas density,3220 g/cm3., liquid density,

0.74g/cm3., L/D =3; Bottom flow rate = 139 kg/hr; distillate flow rate=25kg/hr;

Liquid flow rate at top of the column =75 kg/hr; vapour rate at the top =

100kg/hr: Plate spacing of60 cm; maximum vapour density = 1.603 m/s;

assuming safe operating velocity as 60% of this value, determine (a) the column

cross-sectional area (b) diameter of the column.

A shell-and-tube heat exchanger has one pass on the shell side and two passes

on the tube side (i.e.al-2shell and tube heat exchanger). It is being used for oil

cooling. The oil flows in the tube side. It enters at 1120C and leaves at 78 0C

The shell-and-tube fluid is water at a flow rate of1.35 kg/s, entering at 360C and

leaving at 78 0C. The heat capacity of water is 4180j/(kg. K), and the overall

heat transfer coefficient for the heat exchanger is 350 W/(m2.K). The geometry

factor, F is 1.15. Determine the heat transfer area required for the unit.

A mixture of ethyl alcohol and water containing 25 mole % of the alcohol is

fractionated in a continuous rectification column under all atmospheric pressure.

The required concentration of the overhead product is 80 mole %, and the

permissible alcohol content in the bottom product is not over 0.1 mole %. The

still of the column is supplied with direct steam. Calculate the operating reflux

ratio and the relative molar rates of flow of feed, the direct steam supplied and

the bottom product per kmol of overhead product.

The value of ultimate period of oscillation Pu is 3minutesand the ultimate control gain Kcu is 2,select correct set of parameters for PID controller using Zeigler-nicholas

The unit impulse response of a first-order system is given by 2e^0.5t.the gain and time constant of the process respectively are

Characteristics equation of a closed loop system using a proportional controller with a gain kc is 12s3+19s2+8s+1+kc=0. At the onset of instability the value of kc is?

Determine the equivalent circulating density in ppg for laminar flow of drilling fluid with the following data.. mud weight=9.5ppg, tita 300 =40, tita600=60; plastic viscosity=20cPs; circulation rate=650gpm; hole diameter=8.5 in; drill collect OD=6.75in drill pipe OD=5.0 in; drill collar length=600ft; drill pipe length=10,000ft; true vertical deepth= 9000ft

Calculate the pressure gradient in psi/ft from mud weight of 10.0ppg b. Calculate the pressure gradient in psi/ft from mud weight of 80Ib/ft^3.