Power Engineering 3A2 Chapter 3 Exam Questions and Answers Already Passed

Power Engineering 3A2 Chapter 3 Exam Questions and Answers Already Passed

Main combustible elements in fuel are? - Answers Carbon and hydrogen

Carbon and hydrogen in fuel combine to form? - Answers CO2 and H2O

Products of perfect combustion are? - Answers CO2

H20

N2

SO2

Ash

Products of complete combustion are? - Answers CO2

H20

SO2

N2

02

ASH

Requirements for complete combustion are? - Answers 1. Sufficient air supplied

2. Temp high enough to ignite combustible gases

3. Turbulent air flow to ensure O2 contact

4. Combustion gases must stay in HOT ZONE for sufficient amount of time.

What causes incomplete combustion? - Answers Some of the carbon and hydrogen doesn't combine
with the oxygen.

Incomplete combustion can cause? - Answers Soot build up

Reduces efficiency

Products of incomplete combustion are? - Answers CO2

SO2

H2O

N2

, CO

H2

C

CH4 (methane)

O2

Amount of air required to supply just enough oxygen for complete combustion is? - Answers Theoretical
air

Excess air is expressed as? - Answers a % of the theoretical air

Required excess air depends on? - Answers Fuel

Method of firing

Burner

Furnace design

Load on the boiler

For every kg of oxygen required for combustion, how much air is required? - Answers 4.35kg

analyzing a fuel determines? - Answers Air required for combustion

Heating value of the fuel.

Proximate analysis is used to determine? - Answers % of moisture

volatile matter

fixed carbon

ash

Heating value is expressed in? - Answers kJ/kg for solids

kJ/m3 for gasses

Higher heating value includes? - Answers latent heat of the water vapor in the products of combustion.

Lower heating value is? - Answers Higher heating value - latent heat from the water vapor.

Heating value is determined by? - Answers calculation (dulongs formula)

calorimetry