Chemical Engineering Answers

Find values for residual enthalp and entropy for n-butane gas at 500K and 5 bar as given by redlich kwong equation

Chemical P was fed into a CSTR reactor to react with an excess amount of chemical Q to produce chemical R. However, during the reaction, chemical S was also produced by conversion of chemical R. The reactions involve liquids and follow elementary rate law as follow:

P + Q → R (1)

R → S (2)

The reaction rate constant for chemical P for the first reaction was given as 4 dm3mol-1s-1, while the reaction rate constant for chemical R for the second reaction was given as 6 dm3mol-1s-1. The entering concentration of chemical P was 10 mol dm-3. Answer the following questions using the given information.

a) Write the net rate law for chemical P, R and S. (6 Marks)

b) Write the concentration of chemical P, R and S in terms of space time. (14 Marks)

As a new engineer in a company XZ, your boss has assigned you a project that is related to the removal of pollutant A in pharmaceutical wastewater. To achieve the objective of the project, you had conducted the experiment in a batch mode. The initial concentration of the pollutant A was set at 2.5 mol/dm3. The remaining concentration of the pollutant was identified using a UV-Vis. The complete experimental data obtained is tabulated in Table 1.

Table 1

t (hr) 5 10 15 20 25

A (mol/dm3) 1.95 1.65 1.15 0.88 0.60

a.Determine the removal rate of pollutant A by using numerical method. (15 Marks)

b.Is the removal time of 25 hours sufficiently enough to remove the pollutant A more than 90%? Justify your answer by using answer from (a). (5 Marks)

 The irreversible gas phase reaction A + B --® 2C

is carried out in a PBR. The reaction rate is given as -rA = kCA. The feed is equal molar in A and B and the weight of the catalyst used is 15 kg.

Additional information FA0 = 100 mol/s

k = 1 dm³/kg.s CA0 = 1 mol/dm³

a = 0.064 kg-1

Determine the conversion exiting the reactor.

A first-order, irreversible liquid-phase reaction is taking place in a CSTR and 60% conversion is obtained. What is the minimum number of CSTR of the same size needed to place downstream in series to achieve 90% of total conversion.

Liquid A decomposes by first-order kinetics, and in a batch reactor 50% of A is converted in a 5-minute run. How much longer would it take to reach 75% conversion?

8. Use the steam tables to calculate the enthalpy change (in kJ) of 2 kg-mol of water/steam when heated from:

a) 293 K & 100 kPa to 303 K & 100 kPa.

b) 400 K & 100 kPa to 900 K & 100 kPa..

When the slope of operating line of the rectifying section of distillate column equal to unity?

Two streams of water are mixed to form the feed to a boiler. Process data are as follows:

Feed streams 1: 100 kg/min@30C

Feed streams 2: 195 kg/min@65C

Boiler pressure : 17 bar absolute

Calculate the required heat input to the boiler in kJ/min if the emerging steam is saturated at the boiler pressure. Neglect the kinetic energy, potential energy and work.

Your final answer must be in 1 decimal place with unit kJ/min.

A vapor-compression refrigeration machine uses refrigerant-134a as much as 2 kg/min with operating conditions leaving the evaporator at a temperature of -14°C and a condenser pressure of 0.8 Mpa. Determine the COP value and cooling load of the machine.