Stream Calculator Main Window
The stream calculator unit splits any number of feed streams into two product streams with defined compositions and thermal condition. It may also be used to create a pseudoproduct stream from the blended feeds or by defining the amount of each component in the stream.
Usage
The operation of the stream calculator is determined by the feeds and/or products which have been connected to the unit on the Process Flow Diagram. You should ensure that the streams are correctly defined before entering any data. The Unit Operation icon on the Process Flow Diagram has three locations for product stream connection: the Overhead Product is connected to the top port; the Bottoms Product is connected to the bottom port; and the pseudoproduct is be connected to the right hand side of the icon.
If the unit has no feed, then it may only have a pseudoproduct and be used to create a stream. If there is at least one feed and overhead and bottoms products are defined, the feed will be split between the products. In order to create a stream, a pseudoproduct may be defined instead of, or as well as, the overhead and bottoms product. When splitting and creating streams at the same time, the pseudoproduct is not included in the material balance for the stream splitting.
Feed Scaling button
If there is one or more feed to the unit, this displays the Feed Scaling Window where you may apply scale factors to each feed.
Product Specifications button
If there are overhead and bottoms products, you must define the component splits in the Product Specifications Window.
Pseudoproduct Specifications button
If a pseudoproduct has been defined, you must specify the product composition in the Pseudoproduct Specifications Window.
Overhead Product button
Optionally define the thermal condition of the overhead product in the Overhead Product Conditions Window.
Bottoms Product button
Optionally define the thermal condition of the bottoms product in the Bottoms Product Conditions Window.
Pseudoproduct button
If there is no feed to the unit, you must define the thermal condition of the pseudoproduct in the Pseudoproduct Conditions Window. If there is a feed to the unit, this is optional.
Duty
If the unit is being used to split a stream - i.e. it has an Overhead and Bottoms product - and the overhead and/or bottoms product temperature is being calculated, you may enter a Duty. If the unit is also being used to create a stream, any value you enter for Duty applies only to the stream splitting and is not used in the stream creation heat balance. Alternatively, instead of entering a numeric value for duty, it may be referenced using the Define system relative to any available unit operation or stream parameter calculated elsewhere in the simulation.
Negative rates
It is possible to specify the unit such that negative component rates are calculated in a product stream. In this case, you may select from three possible actions - you may reset any negative rates to zero (this is the default); you may reset the rates to their absolute value; or you may specify that the unit should fail.
Thermodynamic System
You may select the thermodynamic system for the unit from a list of systems as defined in the Thermodynamic Data Window.