BOM Calorimeter

IKA C2000 BOM Calorimeter (Calorific Value)

ASTM D240-02

lab-equipment06

The C2000 basic control calorimeter is the latest system for determining gross calorific values of liquids and solid fuels. A higher level of automation with extremely simple handling characterises this instrument.

In addition to the isoperibolic measurement procedure, a dynamic (reduced-time) working method is also available for the user whilst different working temperatures can be selected for both procedures based on the conditions of the experiment.

The C2000 basic is equipped with a very convenient operating panel through which operation of the device takes place. The graphical display with active back lighting displays the appropriate status messages as well as sample information and experimental status. Library functions and various correction modes make it possible to call up measurements that have already been performed at any time and to edit post-experiment parameters. Connections for balance, printer, keyboard, monitor and sample rack for identifying and managing samples are already integrated into the basic device. To provide a supply of cooling water, the C2000 calorimeter is connected with a standard commercially available thermostat or with an appropriate permanently installed water connection. Both the device technology and the measurement procedure are approved by DIN 51900, ASTM 240D, ISO 1928 and BSI. In combination with special halogen-resistant decomposition vessels of the C5012 series, quantitative decompositions can be performed in parallel to the analysis of gross calorific value to determine halogen and sulphur content.

 

Heat of combustion

The heat of combustion is the energy released as heat when a compound undergoes complete combustion with oxygen under standard conditions. The chemical reaction is typically hydrocarbon reacting with oxygen to form carbon dioxide, water and heat. It may be expressed with the quantities:

  • energy/mole of fuel (kJ/mol)
  • energy/mass of fuel
  • energy/volume of fuel

The heat of combustion is conventionally measured with a bomb calorimeter. It may also be calculated as the difference between the heat of formation of the products and reactants.

 

Heating value

The heating value (or energy value or calorific value) of a substance, usually a fuel or food, is the amount of heat released during the combustion of a specified amount of it. The energy value is a characteristic for each substance. It is measured in units of energy per unit of the substance, usually mass, such as: kJ/kg, kJ/mol, kcal/kg, btu/lb. Heating value is commonly determined by use of a bomb calorimeter.

Heating value unit conversions:

  • kcal/kg = MJ/kg * 238.846
  • Btu/lb = MJ/kg * 429.923
  • Btu/lb = kcals * 1.8

The heat of combustion for fuels is expressed as the HHV, LHV, or GHV.

 

Higher heating value

The quantity known as Higher Heating Value (HHV) [or gross energy or Upper Heating Value (UHV) or Gross Calorific Value (GCV) or Higher Calorific Value (HCV)] is determined by bringing all the products of combustion back to the original pre-combustion temperature, and in particular condensing any vapor produced. Such measurements often use a standard temperature of 25°C. This is the same as the thermodynamic heat of combustion since the enthalpy change for the reaction assumes a common temperature of the compounds before and after combustion, in which case the water produced by combustion is liquid.

The higher heating value takes into account the latent heat of vaporization of water in the combustion products, and is useful in calculating heating values for fuels where condensation of the reaction products is practical (e.g. in a gas-fired boiler used for space heat). In other words, HHV assumes all the water component is in liquid state at the end of combustion (in product of combustion) and that heat above 150°C can be put to use.

 

Lower heating value

The quantity known as Lower Heating Value (LHV), Net Calorific Value (NCV) or Lower Calorific Value (LCV) is determined by subtracting the heat of vaporization of the water vapor from the higher heating value. This treats any H2O formed as a vapor. The energy required to vaporize the water therefore is not released as heat.

LHV calculations assume that the water component of a combustion process is in vapor state at the end of combustion, as opposed to the higher heating value (HHV) (a.k.a. gross calorific value or gross CV) which assumes that all of the water in a combustion process is in a liquid state after a combustion process.

The LHV assumes that the latent heat of vaporization of water in the fuel and the reaction products is not recovered. It is useful in comparing fuels where condensation of the combustion products is impractical, or heat at a temperature below 150°C cannot be put to use.

The above is but one definition of lower heating value adopted by the American Petroleum Institute (API) and uses a reference temperature of 60°F (15.56°C). Another definition, used by Gas Processors Suppliers Association (GPSA) and originally used by API (data collected for API research project 44), is the enthalpy of all combustion products minus the enthalpy of the fuel at the reference temperature (API research project 44 used 25°C. GPSA currently uses 60°F), minus the enthalpy of the stoichiometric oxygen (O2) at the reference temperature, minus the heat of vaporization of the vapor content of the combustion products.

The distinction between the two is that this second definition assumes that the combustion products are all returned to the reference temperature and the heat content from the condensing vapor is considered not to be useful. This is more easily calculated from the higher heating value than when using the preceding definition and will in fact give a slightly different answer.

 

Why we need to know?

  • The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it. The energy value is a characteristic for each substance. It is measured in units of energy per unit of the substance, usually mass, such as; kJ/kg, kJ/mol, kcal/kg, Btu/lb. Heating value is commonly determined by use of a bomb calorimeter.
  • The calorific value (CV) of a fuel is the heat available from that fuel when it is completely burned, expressed as heat units per unit of fuel weight or volume.
  • The gross, or higher, value is determined in the laboratory using a calorimeter. It can be defined as the total heat liberated by the complete combustion of the fuel. It is determined by measuring the heat removed when cooling the products of combustion to a standard reference temperature, and it includes latent heat recovered from condensation of the water vapor component. This water vapor forms as a result of the combustion of any hydrogen molecules contained within the fuel, and the vaporisation of any moisture present.

 

Calorific Value for General Oil and Pentas Flora Recovered Oil:

General Oil

Calorific Value (MJ/kg)

Base Oil

48.00

Bunker Fuel                   < 39.00
Diesel

45.00

Heavy Oil

43.00

Light Fuel Oil 80 cSt

42.00

Medium Fuel Oil 180 cSt

42.00

Tyre Oil

42.00

Waste Engine Oil

38 – 43

Pentas Flora Recovered Oil

Calorific Value (MJ/kg)

Eco Light Fuel Oil

44.00

Super Light Fuel Oil

44.00

Green Light Fuel Oil

44.00

Base Light Fuel Oil

44.00