Mastering Bomb Calorimeters

Proximate Analysis

• Proximate analysis is performed on a solid fuel, such as coal, to determine the percentages of moisture, volatile matter, fixed carbon, and ash.
• The purpose of performing proximate analysis on a fuel is to determine its composition.

Procedure for Proximate Analysis

• Part one of the proximate analysis involves determining the moisture content by heating the fuel in a vacuum oven at 107°C until the weight is constant.

Ultimate Analysis

• Ultimate analysis is used to determine the elemental composition of a fuel, including carbon, hydrogen, oxygen, nitrogen, and sulfur.
• The ultimate analysis includes the percentage of carbon, which also includes the carbon percentage present in the form of CO2.
• The ultimate analysis is performed to determine the exact composition of a fuel and its heating value.

Heating Value of a Fuel

• The calorific value of a fuel is the total heat energy released by complete combustion of a unit quantity of fuel.
• The higher heating value (HHV) of a fuel is the total heat energy released by complete combustion of a unit quantity of fuel.
• The lower heating value (LHV) is the heating value of a fuel after subtracting the latent heat of evaporation contained in the water vapor.
• The reduction in heating value is equal to the mass of water vapor multiplied by the latent heat of evaporation.

Units and Formulas

• The unit for energy and heat is called the joule, named after James Joule.
• The mechanical equivalent of heat is 4.184 joules per calorie.
• The formula for calculating the higher heating value (HHV) of a fuel in a bomb calorimeter is: HHV = (Q x m) / m_fuel.
• The four essential parts required in any bomb calorimeter are the calorimeter vessel, stirrer, thermometer, and heating and cooling systems.

Key Concepts

• James Joule is credited with discovering the relationship between heat and mechanical work.
• The higher heating value (HHV) is the total heat energy released by complete combustion of a unit quantity of fuel.
• The terms gross calorific value and higher heating value can be used interchangeably.
• The terms net calorific value and lower heating value can be used interchangeably.
• The difference between the proximate and ultimate analyses is that proximate analysis determines the percentages of moisture, volatile matter, fixed carbon, and ash, while ultimate analysis determines the elemental composition of a fuel.
• The formula for calculating the heating value of a fuel based on the ultimate analysis is: HV = (339 x %C) + (1230 x %H) + (109 x %S).
• The difference between the as received and moisture free ultimate analysis is that the as received analysis includes the moisture content, while the moisture-free analysis does not.

Test your knowledge on bomb calorimeters and their essential components in this quiz. Learn about the origins of the term "calorie" and its usage in measuring heat. Explore the four necessary parts of a bomb calorimeter and their role in fuel combustion and flue gas analysis.