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Must answer all questions to receive thumbs up credit! What does selective catal

ID: 2086302 • Letter: M

Question

Must answer all questions to receive thumbs up credit!

What does selective catalytic reduction (SCR) attempt to remove from exhaust gases? (A) particulates B) sulfar oxides O (C) nitrogen oxides O (D) volatile organic compounds Which of the following determines the lowest temperature to which water can be cooled by a cooling tower? O (A) the cooling air's dry-bulb temperature O (B) the cooling air's wet-bulb temperature O (C) the cooling air's dew point O (D) the ratio of the cooling air's dry-and wet-bulb temperatures Which of the following determines the velocity of the air blowing through a fluidized-bed combustor? (A) excess oxygen requirements (B) average particle weight O (C) temperature limits for the walls of the combustor O (D) combustion rates 90 kg of ice at 0°C melts completely. The heat of fusion for ice is 320 kJkz. Ifthe final temperature of the water is 0FC, the change in entropy is most nearly (A) kUK O (B) 45kIK (C) 85 kTK O (D) 110 JK A thermodynamic system contained in a rigid vessel with a paddle wheel undergoes an adiabatic process. Kinetic and potential energy changes are negligible. Which of the following equations is correct? (A) AU

Explanation / Answer

1) Ammonia

Selective Catalytic Reduction(SCR) is a advanced emmission control technique used to convert the Nitrogen Oxides(NOX) using the Catalyst into Nitrogen and Water. Generally Ammonia or Urea is used as Reducing Agent.

2)The cooling Airs WetBulb Temperature

Wet bulb Temperature is an important factor in Cooling Tower because it is the lowest Temperature to which water can be cooled. For this Reason the WetBulb Temperature of Air entering the cooling Tower determines the minimumTemperature.

3)Average Particle Wight/Size

When evenly Distributed Air of particles passed through Fluidised Bed Combstion the particles are Undisturbed. So we need to send the Air at Velocity so that Individual particles suspended in the Air stream is called as Fluidized bed. The velocity depends the size or mass of the particles.

4) 110 Kj/K

The heat transfer in converted Ice at 00 C to water at 00 C is Latent Heat.

Given Latent Heat Q = 320KJ/kg

Mass m =90kg

Temperature T = 00 C = 0+273 = 273K

Change in Entropy ds= mQ/T

ds = 90*320/27=106.48 KJ/k which is nearly 110 KJ/K

5) -W =?u

For Adiabatic Process Heat transfer Q=0 so

from first law of thermodynamics for a process

Q = ?u +W

0= ?u + W

?U= -W