Pengerang Hydrocarbon Plant releases aerosol as the major air

polutant which the suspended particles in the gas stream may be

separated by emission control device or combination of devices.

TABLE Q$1$ shows the data of the wasle gas stream from the plant.

TABLE Q$1$: Waste stream data for emissions released from

Pengerang Hydrocarbon Plant

a$.$ The temperature at the ground is $28C.$ The ambient lapse rate

is $-4\mathrm{.}5\frac{C}{k}m$ up to an altitude of $100m.$ Above this the ambient

lapse rate is $+20\frac{C}{k}m.$ Show the atmospheric conditions on

various lapse rates and temperatures diagram. Assume perfectly

adiabatic conditions, determine the plume height and type.

$[5$ marks s$]$

b$.$ Given that Bandar Sentosa is located $5km$ downwind and $75m$

to the side of the plume center line from the plant. Surface is

strong enough to induce convective thermal motions to develop

a mixed layer with an approximately constant lemperature.

Justify that Bandar Sentosa could not meet the annua

Malaysian Ambient Air Quality Standard $($MAAQS $2021)$ for

PMos if there is no air pollution control unit for the particulate

matter. Assume the wind speed and effective stack height are

$2\frac{m}{s}$ and $50m,$ respectively.

c$.$ In order to meet the annual MAAQS $2021$ for PM$2\mathrm{.}5$ of $25\frac{g}{m^3},$

a $1m-$diameter cyclone is proposed to be installed for controlling

the emission of particles. Design the type of cyclone that must

meet the requirement at least $90\%$ efficiency. Assume that the

ground level PM$2$s at Bandar Sentosa is solely contributed by

the emission from the plant based on atmospheric stability

class $C.$

$[15$ marks$]$

d$.$ Based on the conditions determined in part $($c$),$ the particle

diameter has changed into TWO $(2)$ sizes, which are $15m$ and

$25m,$ respectively. The corresponding mass fraction for the

larger and smaller particle are $40wt\%$ and $60wt\%,$ respectively.

Estimate the new value of the design parameters for the cyclone

in order for the ground level concentration at Bandar Sentosa to

meet the emission limit$.$ Justify your answer with calculation and

explanation.

$[20$ marks$]$