The Stream Selector calculation mode allows the user to isolate one feed stream (to this unit operation) from a user-defined list for use in later calculations. This is a very useful when the user must run a simulation repeatedly using different feeds. The following figure of the stream selector main data entry window has been resized to better display in this help topic. All fields and controls were retained.
Use the drop-down list box to choose one of the feed streams to this unit operation. PRO/II copies the selected stream to the PRODUCT stream of the UPSTREAM unit.
Note: The CASESTUDY subsystem can change the order of feed streams. Important for keyword input, this means the position number of the FEED streams on the FEED statement may be changed by CASESTUDY. That should not influence the behavior of this data entry window, because the drop-down list always should be populated with all streams in the list of feeds.
Stream Selector Example:
Use one keyword input file to run five different feed stocks through a propane/propylene splitter (see Application Brief P1 for column details). The STREAM SELECTOR operation can be used with CASE STUDY, to vary feed streams while limiting the simulation to one input file.
TITLE CASE=CASE1, PROBLEM=P1MOD
COMPONENT DATA
LIBID 1, C2 / 2, PROPENE / 3, C3 / 4, NC4
THERMODYNAMIC
METHOD SYSTEM=PR, DENSITY(L)=LK
KVALUE
KIJ 2,3,0.00663
STREAM DATA
PROP STREAM=A1, PHASE=L, PRESSURE=240, COMP=0.3/550/200/5
PROP STREAM=A2, PHASE=L, PRESSURE=240, COMP=1.0/540/210/7
PROP STREAM=A3, PHASE=L, PRESSURE=240, COMP=0.8/555/192/6
PROP STREAM=A4, PHASE=L, PRESSURE=240, COMP=2.3/545/206/9
PROP STREAM=A5, PHASE=L, PRESSURE=240, COMP=1.8/560/213/8
UNIT OPERATION DATA
UPSTREAM UID=UP1,
FEED=A1, A2, A3, A4, A5
PRODUCT M=FD
OPERATION SELECTOR, STREAM=1
COLUMN UID=C3SP
PARA TRAY=149, IO=40
FEED FD, 110
PROD OVHD=TOPS, 542, BTMS=BOTS
COND TYPE=BUBB
PRESSURE 1,220/2,225/149,250
HEAT 1,1/2,149
ESTI MODEL=CONV, RRATIO=15
SPEC STRM=BOTS, COMP=2, FRAC(V), VALUE=0.04
SPEC STRM=TOPS, COMP=3, FRAC(W), VALUE=0.004
VARY HEAT=1,2
CASESTUDY OLDCASE=CASE1, NEWCASE=CASE2
CHANGE UPSTREAM=UP1, PRODUCT, VALUE=2