Chemical Engineering Answers

The water problem flows at a constant mass flow rate of 7 kg / s into a vertical cylindrical tank. Water is discharged near the base of the tank at a mass flow rate proportional to the height of the liquid in the tank, ime = 14 kg / s, where L is the instantaneous height of the liquid, in m. The base area of ​​the circle is 0.2 m2. Water density is constant at 1000 kg / m3. If the tank is empty at first, determine the change in liquid height over time.

One kmol of a gas at 298 K and 1 bar traces the path A and B as follows:

1-2 Compressed adiabatically to 10 bar pressure

2-3 heated at constant pressure to 623K

3-4 Expanded at constant temperature to 1 bar

2-1 Cooled at constant pressure to 298 K

Calculate Q, W, ΔU and ΔH for each step and for entire cycle, Cp = 29.17 kJ/kmol-K.

Calculate the work done for the adiabatic compression of ethane from 150 kPa to 600 kPa

at 20°C. Assume ethane to be an ideal gas. The heat capacity of ethane is given by

𝐶𝑝

0= 1.48 + 4.124 X 10-2 T + 1.23 X 10-5 T

2

- 1.74 X 10-9 T

3

( T in K, Cp = Cal/mol-K)

 A saturated liquid ethyl acetate compressed from 400kPa to 1000Kpa at 300K. Calculate 

the change in enthalpy and entropy during this compression process.

For Saturated liquid ethyl acetate at 300K; VL = 2×10-3 m3

/kg and β = 3 × 10-3 K-1

In a typical fruit drying process, fresh apricots without seeds (contains 82% of humidity) are dried in a dryer. After drying process, dry apricots contain 22% humidity. What is the mass loss of apricots during drying process. In order to obtain 1 kg dry apricots, how many kg of fresh apricots arerequired.

90kg alcohol-water mixture containing 25% alcohol is fed to a distillation column. Top and bottom product contains 85% and 3.2% alcohol, respectively. What percentage of alcohol in feed is recovered in top stream?

A hot fluid at 200 °c enters a heat exchanger at a mass flow rate of 10000kg/hr. It's specific heat is 2000j/kg°c. It is to be cooled by another fluid enters at 25°c with a mass flow rate 2500kg/hr and specific heat is 400 j/kg°c. The overall heat transfer coefficient based on outside area of 25m^2 is 250W/m^2°c. Find the exit temperature of the hot fluid when the fluid are in parallel flow and counter flow

A solution of washed raw cane sugar is coloured by the presence of impurities. It is to be decolourised by the treatment with an adsorptive carbon in a contact filtration plant. The data for an equilibrium isotherm is given below. The original solution has a colour concentration of 9.6 measured on an arbitrary scale and it is desired to reduce colour to 10% of its original value

Kg carbon/kg solution:

0.001

0.004

0.008

0.02

0.04

Colour units /kg solution

9.6

8.6

6.3

4.3

1.7

0.7

Convert the data to a suitable form for plotting the equilibrium isotherm and determine the quantity of fresh carbon required per 1000 kg of solution for a two stage counter-current operation?

Explain briefly with step by step process?

The inreversible isomerization

A->B was carried out in a batch reactor and the following concentration-time data were obtained: T(min) 0 3 5 8 10 12 15 17.5

CA(mol/dm3) 4.0 2.89 2.25 1.45 1.0 0.65 0.25 0.07

(a) Use regression to determine the reaction order, a, and the specific reaction rate, ka.

The flat base of the bottom of an electric water heater is made of a 2 mm thick steel plate. thermal conductivity of 40 W/(m. oC), and an insulating plate with a thickness of 4 mm and thermal conductivity of 0.06 W/(m.oC). Between the steel and insulating plates there is an electrical resistance (RE) that dissipates a power of 800 W. 

Consider the steady state situation with boiling water at a temperature of 100 oC and with a coefficient of heat transfer by convection of 3000 W/(m2. oC), while the ambient air, which is in contact with the insulator, it remains at a temperature of 25oC and a convection heat transfer coefficient of 10 W/(m2.oC).

Considering a perfect thermal contact between the electrical resistance and the steel and insulating sheets and that the base of the heater has an area of 0.018 m2, determine: 

a) The temperature (TR) of the electrical resistance

b) The rate of heat lost to the air through of the insulating plate

ç). The rate of heat lost to water through the steel plate