Engineering Answers

i.In a cyclic process heat transfer are +14.7 kJ, -25.2 kJ,

-3.56kJ and +31.5 kJ. What is the network for the cyclic process?

ii. Apply the steady flow energy equation to a Turbine and deduce an expression for work

A closed system consists of 1 kg of air which is initially at 1.5bar and 67°C. The volume doubles as the system undergoes a process according to the law PV1.2 = C. Find the work done, heat transfer and the change in entropy during this process. For air R= 0.287 kJ/kgK and γ = 1.4

find a homogeneous linear equation with real, constant coefficients that is satisfied by y=6+3xe^x–cos x

To determine and verify experimentally the law for total resistance (RT) of a series-parallel combination circuit.

2. To verify that the voltage across each leg in a parallel circuit is the same as the voltage across the parallel network.

Equipment

Project board 1 x 68Ω resistor

Multi-meter 1 x 82Ω resistor

Variable power supply 1 x 150Ω resistor

Wires 1 x 1k2 Ω resistor

1 x 10kΩ resistor

A system of forces 340 N, 760 N, 800 N, 600 N, 700 N and 500 N (in order) acting on

900 mm by 400 mm plate (with negligible thickness) is shown. Find the resultants with

respect to O.

1. Explain in you own words, how Thevenin's theorem is used to convert any linear two-terminal network into a simple equivalent circuit consisting of a resistance in series with a voltage source.
2. Explain in advantage if using Thevenin's theorem when finding load currents in a dc circuit.

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.