HTRI_2005年成都年会-板式换热器培训班资料Xph.ppt

1、,Fluid Properties,Module 3,Fluid PropertiesModule 3,Objectives Describe HTRI methods to specify fluid properties grid properties component-by-component Give practical guidelines to best specify fluid properties Develop grid properties for ammonia condenser,Fluid Property Data,Density Viscosity Press

2、ure drop Specific heat Single-phase heat release temperature profile Thermal conductivity Heat transfer coefficient,Heat Release Data,Temperature/enthalpy/weight fraction vapor data Specific heat for single-phase Vapor-liquid equilibrium model for two-phase Temperature profile Mean temperature diffe

3、rence,Fluid Property Options,Mixture properties via grid User-specified heat release only Property generator button,Mixture Properties via Grid,T&P Reference pressures (1 minimum, 12 maximum) Reference temperatures for each pressure (3 minimum, 30 maximum),Mixture Properties via Grid,Heat Release En

4、thalpy for each reference pressure and temperature Weight fraction vapor for two phase,Mixture Properties via Grid,Property Grid Required properties are identified,Do not leave blanks even if case runs,Mixture Properties via Grid,Property Monitor shows grid established for case This example shows 2

5、pressures and 10 temperatures,Property Monitor,Xphe interpolates temperature and pressure to get properties at any required temperature and pressure,Mixture Properties via Grid,Interpolation Methods Quadratic fit between reference temperatures Linear fit between reference pressures,Built-in Property

6、 Generator,VMGThermo Xchanger Suite 4.0 PPDS Discount available at M REFPROP /srd/nist23.htm HYSYS AspenTech PRO/II Simulation Sciences,Fluid Property Options,Component by component Three heat release options,Suitable when data are insufficient foraccurate grid,Component by ComponentHeat

7、 Release Input Method,User-specified Three or more enthalpies for each reference pressure Same as grid heat release method,Component by ComponentHeat Release Input Method,Specified dew/bubble point Dew point at outlet pressure Bubble point at inlet pressure,Two-point heat release option,Component by

8、 ComponentHeat Release Input Method,Program-calculated Grid generated at 12 pressures and 30 temperatures Pure components HTRI databank DIPPR Ideal mixtures User-defined components,Component by ComponentProgram-Calculated Heat Release,Liquid and/or vapor properties Two temperatures linear grid creat

9、ed for r, k, cp logarithmic grid created for m One temperature constant properties,Component by ComponentProgram-Calculated Heat Release,Constants subpanel Average latent heat required for user-defined two-phase fluids Liquid critical pressure required for user-defined boiling fluid With hydrocarbon

10、 option, vapor/liquid properties not required,Component by ComponentProgram-Calculated Heat Release,VLE subpanel Activity coefficients(K-value data) required for mixtures User-specified vapor pressure data Antoine constants calculated by Xchanger Suite,Fluid Property Options,Component and grid prope

11、rties User-specified heat release only Grid properties used where specified,Recommended Guidelines,Grid Available?,Grid Adequate?,yes,Mixture properties via grid,yes,Single-Phase,Two-Phase,no,no,HTRI Databank OK?,Heat release data provided?,no,no,yes,yes,Component by component User-specified heat re

12、lease,Component by component Program-calculated heat release User defined component,Component by component Program-calculated heat release HTRI databank component(s),Grid Available?,Data provided by process group Data calculated by Property Generator Composition known Mixture model identified Flash

13、type (integral versus differential),Grid includes all required heat release and fluid property data,Grid Adequate?,Do pressure and temperature ranges cover operating conditions? Subcooled and superheated regimes Piping and column conditions for thermosiphons More than two reference pressures for low

14、 pressure thermosiphons,Grid Adequate?,Are data identified for all temperature and pressure points? Are variations in data smooth? Heat release data must be monotonic with temperature,Grid is adequate if answers to these questions are yes,HTRI Databank OK?,Pure substances Within temperature and pres

15、sure range DIPPR can be used VLE subpanel can be used for more accurate MTD Ideal mixtures Single-phase gas-gas mixtures One condensing/boiling component with inerts,Stream Properties,Displays fluid physical properties for each fluid at inlet and outlet conditions,Example 3Ammonia Condenser,Open Exa

16、mple3.htri Condensing NH3 Cooling water Specified input temperature modified Inlet pressure respected,Example 3HTRI Databank,Property Monitor HTRI databank 12 pressures, 10 temperatures,Example 3Grid Properties with VMG,Create grid of properties using VMGThermo Run case Which results are more accura

17、te?,Example 3Lower MTD,Reopen Example3.htri Remove hot fluid temperatures Specif hot inlet pressure of 190 psia Run case Compare results with VMG,Additional Guidelines for Mixture Properties via Grid,Avoid using too many temperatures or isobars One isobar for high pressure Three or more isobars for medium pressure and vacuum conditions,Additional Guidelines for Mixture Properties via Grid,Include bubble point and dew point temperatures for narrow boiling ranges (BR) Make sure all reference temperatures are not