Gasification: Energy Balance Tab

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Variable Definitions, Ranges and Default Values

The following table shows a brief description of the variables appearing in this tab. The table also displays their default values and their generally acceptable range. Note that due to how the variables are used in the modeling equations, the range of acceptable values may be further reduced; for more details, see Gasification: Modeling Assumptions & Constraints.

Variable

Default Value

Range

 

● Fuel Stream: Dry Fuel (%)
The mass fraction of dry fuel in the fuel stream.

0.0

0-100

● Fuel Stream: Water (%)
The mass fraction of water in the fuel stream.

0.0

0-100

● Fuel Stream: HHV of Dry Fuel (kJ/kg)
The total higher heating value of dry fuel. This is calculated as the ratio of total HHV-based power input of dry fuel to total flow of dry fuel.

0.0

Positive

● Fuel Stream: LHV of Dry Fuel (kJ/kg)
The total lower heating value of dry fuel. This is calculated as the ratio of total LHV-based power input of dry fuel to total flow of dry fuel.

0.0

Positive

● Fuel Stream: Standard Enthalpy (kW)
The enthalpy of the fuel stream at standard state and 25 oC.

0.0

Positive

● Fuel Stream: Enthalpy (kW)
The enthalpy of the fuel stream.

0.0

Positive

● Fuel Stream: Std Heat for Water Evap. (kW)
The heat required to vaporize any liquid water present in the fuel stream at 1 bar and 25 oC.

0.0

Positive

● Oxidant Stream: Water (%)
The mass fraction of water in the oxidant stream.

0.0

0-100

● Oxidant Stream: Standard Enthalpy (kW)
The enthalpy of the oxidant stream at standard state and 25 oC.

0.0

Positive

● Oxidant Stream: Enthalpy (kW)
The enthalpy of the oxidant stream.

0.0

Positive

● Oxidant Stream: Std Heat for Water Evap. (kW)
The heat required to vaporize any liquid water present in the oxidant stream at 1 bar and 25 oC.

0.0

Positive

● Moderator Stream: Water (%)
The mass fraction of water in the moderator stream.

0.0

0-100

● Moderator Stream: Standard Enthalpy (kW)
The enthalpy of the moderator stream at standard state and 25 oC.

0.0

Positive

● Moderator Stream: Enthalpy (kW)
The enthalpy of the moderator stream.

0.0

Positive

● Moderator Stream: Std Heat for Water Evap. (kW)
The heat required to vaporize any liquid water present in the moderator stream at 1 bar and 25 oC.

0.0

Positive

● Producer Gas Stream: Dry Producer Gas (%)
The mass fraction of dry producer gas in the producer gas stream.

0.0

0-100

● Producer Gas Stream: Water (%)
The mass fraction of water in the producer gas stream.

0.0

0-100

● Producer Gas Stream: HHV of Dry P. G. (kJ/Nm3)
The higher heating value of dry producer gas expressed as energy per unit standard volume. This is calculated as the ratio of total HHV-based power output of dry producer gas to total standard volume flow of dry producer gas.The standard volume flow of dry producer gas is calculated based on the specified standard temperature and pressure values for the flowsheet considered (0oC and 1 bar by default).

0.0

Positive

● Producer Gas Stream: LHV of Dry P. G. (kJ/Nm3)
The lower heating value of dry producer gas expressed as energy per unit standard volume. This is calculated as the ratio of total LHV-based power output of dry producer gas to total standard volume flow of dry producer gas.The standard volume flow of dry producer gas is calculated based on the specified standard temperature and pressure values for the flowsheet considered (0oC and 1 bar by default).

0.0

Positive

● Producer Gas Stream: Standard Enthalpy (kW)
The enthalpy of the producer gas stream at standard state and 25 oC.

0.0

Positive

● Producer Gas Stream: Enthalpy (kW)
The enthalpy of the producer gas stream.

0.0

Positive

● Producer Gas Stream: Std Heat from Water Cond. (kW)
The heat released from condensation of water vapor present in the producer gas stream at 1 bar and 25 oC.

0.0

Positive

● Ash Stream: HHV or LHV (kJ/kg)
The total higher (or lower) heating value of the ash stream. This is calculated as the ratio of total power output of ash stream to total flow of ash stream.

0.0

Positive

● Ash Stream: Standard Enthalpy (kW)
The enthalpy of the ash stream at standard state and 25 oC.

0.0

Positive

● Ash Stream: Enthalpy (kW)
The enthalpy of the ash stream.

0.0

Positive

● Total Enthalpy Change In (kW)
The sum of the differences between enthalpy and standard enthalpy over all input (fuel, oxidant, and optionally, moderator) streams considered.

0.0

Positive

● Total Enthalpy Change Out (kW)
The sum of the differences between enthalpy and standard enthalpy over all output (producer gas, ash) streams.

0.0

Positive

● Standard Heat of Reaction (kW)
The standard enthalpy of the overall gasification reaction calculated at 25 oC.

0.0

Positive

● Heat Losses (kW)
The total heat losses of the gasification operation.

0.0

Positive

Symbol Key: ○ User-specified value (always input); ● Calculated value (always output); ◙ Sometimes input, sometimes output

Specification Choices / Comments

For more details on how the values shown in this tab are calculated, see Gasification: Modeling Calculations.