Multi-Effect Evaporation: Heating Tab

This tab appears on the interface dialog of the Continuous Multi-Effect Evaporation operation if the Vapor Recompression Option is set to “None” in the Oper. Conds Tab (see Multi-Effect Evaporation: Oper. Conds Tab).

Variable Definitions, Ranges and Default Values

The following table shows a brief description of the variables appearing in this tab; for a detailed description of these variables, see Multi-Effect Evaporation: Description of Terms 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 Multi-Effect Evaporation: Modeling Assumptions & Constraints.

Variable	Default Value	Range

○ Heating Agent Name Indicates the heating agent used in the evaporator. Click on the list box to bring up a list of available heating agents in order to select one.	Steam	Any Heating Agent
● Supply Temp. of Heating Agent (^oC) The temperature of the heating agent before the heat transfer.	152.0	Positive
● Return Temp. of Heating Agent (^oC) The temperature of the heating agent after the heat transfer.	152.0	Positive
● Mass-to-Energy Factor of Heating Agent (kcal/kg) The specific heat source of the heating agent between supply and return.	503.683	Positive
● Duty of Heating Agent (kcal/h) The heat transfer rate of the heating agent.	0.0	Positive
● Flow of Heating Agent (kg/h) The mass flow rate of the heating agent.	0.0	Positive
● Flow of Heating Fluid in First Effect (kg/h) The mass flow rate of the heating fluid in the first effect. If no vapor recompression is used, this matches the flow of heating agent.	0.0	Positive
● Outlet Temp. of Heating Fluid in First Effect (^oC) The temperature of the heating fluid at the steam chest outlet of the first effect. If no vapor recompression is used, this matches the return temperature of the heating agent.	152.0	Positive
◙ Condensing Temp. of Heating Fluid in First Effect (^oC) The temperature at which the heating fluid will condense in the steam chest of the first effect (corresponding to the pressure that the heating fluid exhibits in the steam chest of that effect). If no vapor recompression is used, the heating fluid matches the heating agent and the condensing temperature indicates the pressure of heating agent in the steam chest of the first effect.	152.0	[Supply Temp., Return Temp.]
● Specific Heat Duty of Heating Fluid in First Effect (kcal/kg) The specific heat source of the heating fluid used in the steam chest of the first effect. If no vapor recompression is used, this is the same as the mass-to-energy factor of the heating agent.	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 available specification choices in this tab are implemented, see Multi-Effect Evaporation: Modeling Calculations.