MODULE IV - Condensing boiler technology Page 5

MODULE IV Condensing boiler technology Page 5

Exercise 2

Fill in the table the characteristic values of the different fuels.
Describe the combustion process of natural gas. Distinguish between complete and incomplete combustion in your explanations. Complete the "normal combustion" diagram below.
Explain the technical terms of the diagram.
Determine the Ho : Hu - ratio for all fuels (in [%]).

Note: Since we are dealing with a condensing boiler, all other fuels can be neglected.

Gas composition [in %]
Component	City gas	Gas piped over a long distance	Natural gas L	Natural gas H
Hydrogen H2			-	-
Methane CH4
Carbon monoxide CO			-	-
Propane, butane, ethane
Carbon dioxide CO2
Nitrogen N2
Oxygen O2			-	-

Values that express the combustion heat
Fuel	Calorific value Ho [kWh/kg]	Heating value Hu [kWh/kg]	Theoretical air requirement Lmin [m3/kg]	Carbon dioxide CO2max [%]
Anthracite coal
Coke
Dry wood
Dry peat
Fuel oil EL
	[kWh/m3]	[kWh/m3]	[m3/m3]	[%]
Natural gas L
Natural gas H
City gas
Propane
Butane

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