The ultimate analysis for a MSW sample consists of: Carbon 26.5% Hydrogen 4% Oxy
ID: 2078973 • Letter: T
Question
The ultimate analysis for a MSW sample consists of: Carbon 26.5% Hydrogen 4% Oxygen 22% Nitrogen 0.7% Sulfur 0.3% Ash 19% Fuel moisture 28.5% The products of combustion are: Carbon dioxide 1.1 lb. Moisture from hydrogen 0.3 lb. Oxygen 0.7lb Nitrogen 5 lb. Sulfur dioxide 0.01 lb. Moisture from fuel 0.3 lb. Moisture from air 0.1 lb. Total moisture 0.7 lb. Total 8.21 lb. Determine the high heating value (HHV), the low heating value (LHV) and the temperature developed during combustion (Tcomb) for ambient temperature of 70oF.
Explanation / Answer
Heating Value: The heating value of any fuel is the energy released per unit mass or per unit volume of the fuel when the fuel is completely burned. The heat of combustion for fuels is expressed as the HHV, LHV
The term calorific value is synonymous to the heating value. Typical units for expressing calorific or heating value are MJ/kg & MJ/m3 in SI units or Btu/lb & BTU/SCF in English units. The heating value of a fuel depends on the assumption made on the condition of water molecules in the final combustion products.
High Heating Value: It is referd to the condition in which the water is condensed out of the combustion products. The higher heating value includes the sensible heat and latent heat of vaporiztion especially for water. In other words, HHV assumes all the water component is in liquids state at the ends of the combustion .
The lower heating value (LHV), on the other hand refers to the condition in which water in the final combustion products remains as vapor (or steam); i.e. the steam is not condensed into liquid water and thus the latent heat is not accounted for. The LHV assumes that the latent heat of vaporization of water in the fuel and the reaction products is not recovered.
The term net heating value (NHV), net calorific value (NCV) or lower calorific value (LCV) refers to LHV.
The term gross heating value (GHV) or higher calorific value (HCV) refers to HHV.
Given:
High Heating Value= (1.1*0)+(0.3*324)+(0.7*0)+(5*0)+(0.1*0)=97.2lb
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