The minimum reflux ratio when simulating with PRO/II is -1

Thread Content

This post was last edited by longkui1990 on 2011-11-23 14:01. Seeking advice: What thermodynamic methods should be used to simulate ammonia evaporation (water and a small amount of ammonia gas) using PRO/II? When using PRO/II to simulate ammonia evaporation, the minimum reflux ratio is -1; I seek advice from experts. $ Generated by PRO/II Keyword Generation System $ Generated on: Tue Nov 15 13:44:31 2011 TITLE TOLERANCE STREAM =0.01,-0.555556,0.01,0.01, TEMPERATURE=-0.0555556, & PRESSURE=0.005, DUTY=0.001, MISCELLANEOUS=0.003, FLASH=3E-6 DIMENSION SI, TEMP=C, PRES=KPA, WT=KG, TIME=HR, LENGTH=M, & FLENGTH=MM, LIQVOL=M3, VAPVOL=M3, LDENSITY=KG/M3, & VDENSITY=KG/M3, XDENSITY=DENS, SPVOL=M3/KG-MOL, & SPVVOL=M3/KG-MOL, ENERGY=KJ, WORK=KW, DUTY=KJ/HR, & CONDUCT=W/MK, HTCOEF=KW/MK, FOUL=MK/KW, VISCOSITY=PAS, & KVIS=CST, SURFACE=N/M, STDTEMP=0, STDPRES=101.325, & STDVAP(M3/KG-MOL)=22.414, PBASIS(KPA)=101.325 SEQUENCE SIMSCI CALCULATION TRIALS=20, RECYCLE=ALL, TVPBASIS=37.7778, & RVPBASIS=APIN, COMPCHECK=CALC, MAXOPS=1000000, CDATA=FIX, & FLASH=DEFAULT, DVARIABLE=ON COMPONENT DATA LIBID 1,H2O/2,NH3, BANK=SIMSCI,PROCESS THERMODYNAMIC DATA METHOD SYSTEM=NRTL, SET=NRTL01, DEFAULT STREAM DATA PROPERTY STREAM=S1, TEMPERATURE=78, PRESSURE=150, PHASE=M, & COMPOSITION(WT,KG/H)=1,11864/2,41.5 UNIT OPERATIONS SHORTCUT UID=SCD1 FEED S1 PRODUCT STREAM=S2, RATE(WT)=400, PHASE=L, DP=0 PRODUCT STREAM=S3, PHASE=L, DP=0 CONDENSER TYPE=BUBB EVALUATE MODEL=CONV, TRIAL=50, KEYLIGHT=2, KEYHEAVY=1, & RRMIN=1.4 FINDEX 2 SPEC STREAM=S3,FRACTION(WT), COMP=1,WET, VALUE=0.99985 SPEC STREAM=S2,FRACTION(WT), COMP=2,WET, VALUE=0.1 CONTROLLER UID=CN1 SPEC STREAM=S2, TEMPERATURE(C), VALUE=103 VARY STREAM=S1, PRESSURE(KPA) CPARAMETER IPRINT, SOLVE END