Material Flow Section - HOC

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Navigation: Models ➔ Common Sections ➔ Material Flow Section ➔ Heats of Combustion, Heating Values

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This section is used to display the included properties for: Heats of Combustion (Build 139 and later) and Heating Values (Build 138 and earlier)

Heats of Combustion

Tag (Long/Short) Input / Calc Description/Calculated Variables / Options

Heat of Combustion

Only available in Build 139 or later. For Build 138 or earlier, refer to Heating Values. These will only be shown if the user has chosen to display the HeatsOfCombustion Properties on the Plant Model - Views tab page or from the Include Properties dropdown list on the first page of the material Flow section.

The Heat of Combustion is the heat released (ie. enthalpy change) if the stream components undergo complete combustion with oxygen to produce carbon dioxide gas and water. The higher heating value (HHV) (or Gross Calorific Value) is calculated by assuming that the water produced is liquid water. The lower heating value (LHV) (or Net Calorific Value) is calculated by assuming that the water is produced as steam.

NOTE:

  1. The Heat of Combustion is only calculated for components which contain only carbon (eg. carbon solid), only hydrogen (eg. hydrogen gas) or only carbon and hydrogen (ie. a hydrocarbon, eg. methane (CH4)).
  2. Components which contain only carbon and oxygen (eg. carbon monoxide) and only carbon, hydrogen and oxygen (eg. ethanol) are also included.
  3. If oxygen gas and/or carbon dioxide gas are not included in the project then the following numbers will be assumed when calculating the heat values (all values are at 298K).
Species Heat of Formation (Hf) (kJ/mol) Heat Capacity (Cp) (J/K.mol)
Oxygen (O2(g)) 0 29.379
Carbon Dioxide (CO2(g)) -393.8 37.171
Reference:The Properties of Gases and Liquids, 4th Edition (Reid, Prausnitz and Poling)
HoC (Heats of Combustion)
HHV.M150 Calc Higher Heating Value - Heat released if the stream components undergo complete combustion with oxygen to produce carbon dioxide gas and liquid water at 150°C and 1 atmosphere pressure on a mass basis.
HHV.M25 Calc Higher Heating Value - Heat released if the stream components undergo complete combustion with oxygen to produce carbon dioxide gas and liquid water at 25°C and 1 atmosphere pressure on a mass basis.
HHV.Ml25 Calc As above except on a molar basis.
HHV.V25 Calc As above except on a volumetric basis. NB Gas mass per volume calculated at 25°C and stream pressure.
HHV.M Calc Higher Heating Value - Heat released if the stream components undergo complete combustion with oxygen to produce carbon dioxide gas and liquid water at the stream temperature and pressure on a mass basis.
HHV.Ml Calc As above except on a molar basis.
HHV.V Calc As above except on a volumetric basis. NB Gas mass per volume calculated at the stream temperature and pressure.
LHV.M150 Calc Lower Heating Value - Heat released if the stream components undergo complete combustion with oxygen to produce carbon dioxide gas and steam at 150°C and 1 atmosphere pressure on a mass basis.
LHV.M25 Calc Lower Heating Value - Heat released if the stream components undergo complete combustion with oxygen to produce carbon dioxide gas and steam at 25°C and 1 atmosphere pressure on a mass basis.
LHV.Ml25 Calc As above except on a molar basis.
LHV.V25 Calc As above except on a volumetric basis. NB Gas mass per volume calculated at 25°C and stream pressure.
LHV.M Calc Lower Heating Value - Heat released if the stream components undergo complete combustion with oxygen to produce carbon dioxide gas and steam at the stream temperature and pressure on a mass basis.
LHV.Ml Calc As above except on a molar basis.
LHV.V Calc As above except on a volumetric basis. NB Gas mass per volume calculated at the stream temperature and pressure.

Heating Values

Only available in Build 138 or earlier. For Build 139 or later, refer to Heats of Combustion.

The Heating Value is the Heat of Combustion (ie. heat released, enthalpy change) if the stream components undergo complete combustion with oxygen to produce carbon dioxide gas and water. The higher heating value (Hi) (or Gross Calorific Value) is calculated by assuming that the water produced is liquid water. The lower heating value (Lo) (or Net Calorific Value) is calculated by assuming that the water is produced as steam.

NOTE: The Heating Value is only calculated for components which contain only carbon (eg. carbon solid), only hydrogen (eg. hydrogen gas) or only carbon and hydrogen (ie. a hydrocarbon, eg. methane (CH4)). Components which contain only carbon and oxygen (eg. carbon monoxide) and only carbon, hydrogen and oxygen (eg. ethanol) are also included.

These heating values will only be shown if the user has chosen to display Heating Values using the ShowHeatingValues tickbox.

Tag (Long/Short) Input / Calc Description/Calculated Variables / Options
Heating Values (Combustion)
HVHiM Calc Heating Value - Heat released if the stream components undergo complete combustion with oxygen to produce carbon dioxide gas and liquid water at the stream temperature and pressure on a mass basis.
HVHiMl Calc As above except on a molar basis.
HVHiV Calc As above except on a volumetric basis.
HVHiNV Calc As above except on a normal volume basis.
HVLoM Calc Heating Value - Heat released if the stream components undergo complete combustion with oxygen to produce carbon dioxide gas and steam at the stream temperature and pressure on a mass basis.
HVLoMl Calc As above except on a molar basis.
HVLoV Calc As above except on a volumetric basis.
HVLoNV Calc As above except on a normal volume basis.
HVHiM25 Calc Heating Value - Heat released if the stream components undergo complete combustion with oxygen to produce carbon dioxide gas and liquid water at 25°C and 1 atmosphere pressure on a mass basis.
HVHiMl25 Calc As above except on a molar basis.
HVHiV25 Calc As above except on a volumetric basis.
HVHiNV25 Calc As above except on a normal volume basis.
HVLoM25 Calc Heating Value - Heat released if the stream components undergo complete combustion with oxygen to produce carbon dioxide gas and steam at 25°C and 1 atmosphere pressure on a mass basis.
HVLoMl25 Calc As above except on a molar basis.
HVLoV25 Calc As above except on a volumetric basis.
HVLoNV25 Calc As above except on a normal volume basis.

If oxygen gas and/or carbon dioxide gas are not included in the project then the following numbers will be assumed when calculating the heat values (all values are at 298K).

Species

Heat of Formation (Hf) (kJ/mol)

Heat Capacity (Cp) (J/K.mol)

Oxygen (O2(g)) 0 29.379
Carbon Dioxide (CO2(g)) -393.8 37.171

Reference: The Properties of Gases and Liquids, 4th Edition (Reid, Prausnitz and Poling)