热力学设置，这个在chemcad中 help文档中就有，不过还想发一下。

liyongrui · 发表于 1970-1-1 08:00:00

热力学设置，这个在chemcad中 help文档中就有，不过还想发一下。
Global K-value Option

Choose the K-value to use for this flowsheet. K-values are the expressions that relate liquid and gas phase vapor liquid equilibrium (VLE). You can use local K-values on UnitOps to override the global K-value setting.

Ethane/Ethylene, Propane/Propylene

Use special binary interaction parameters for ethane/ethylene and propane/propylene systems. This option is only valid when the SRK or Peng-Robinson method is used for K-values. Typically, the special BIPs will give the best results near the critical points.

Vapor Phase Association

Certain compounds, especially carboxylic acids, have the tendency to dimerize or even polymerize in the vapor phase. Selecting this option accounts for this vapor phase association. Note that this option will activate the Poynting correction.

Vapor Fugacity/Poynting Correction

This method is a correction for pressure of the vapor phase fugacity when using activity coefficient methods. If this option is selected, the vapor fugacity will be calculated using the SRK equation of state. Typically, it is safe to ignore this correction at lower operating pressures. This option may only be used with a liquid activity coefficient method and is recommended when pressure is above 3 atm.

This option also turns on the HF hexamerization when HF is present and activity coefficient models have been selected.

SRK/PR Alpha function

For SRK and Peng-Robinson EOS models, you are allowed to choose either the standard alpha function or the newer Boston-Mathias alpha function. The default is the standard alpha function. Boston-Mathias is reccomended for temperatures above critical.

Global Phase Option

Instructs the program to make all flashes three-phase flashes (LLV) or two-phase flashes (LV). This can only be used with K-value methods capable of performing three-phase flashes: MARG, NRTL, UNIF, UNIQ, etc.

Water/Hydrocarbon Solubility

Change the immiscibility status of water. Water immiscibility may be invoked for any method, except for liquid activity coefficient methods; for those options, water is always considered to be miscible. When water is immiscible for applicable models, the K-value of water will be calculated by a special routine that accounts for the solubility of water in the hydrocarbons. If the miscible setting is chosen, the global K-value is used for water.

Wilson model salt

Account for the effect of dissolved salts on the vapor-liquid equilibrium of the solvents. This option may only be used with the Wilson equation.

No. of BIP sets

CHEMCAD allows you to have up to ten (10) sets of BIPs for each activity coefficient method. This gives you the flexibility of using one set of BIPs in one section of a flowsheet and a different set in another. A typical use of this would be when you know that two liquid phases exist in the condenser of a distillation column. You can choose to use NRTL LLE BIPs in the condenser and NRTL VLE for the rest of the column.

Default BIP set

Defines the set to be used globally by the program. Default value is 1. Other sets are treated as local sets.

Clear all local K models/BIPs

If selected, allows you to clear your local K-value options. The entire flowsheet will be reset to use the global K model.

Clear all tray BIPs

If selected, allows you to clear all tray BIPs.

Set local K models/BIPs

If selected, upon exiting the K-value screen, the program will go into selection mode and allow you to choose one or more units from the flowsheet. It will then present you with an input screen where you can define what K-value model or BIP set is applicable to the particular unit operation.

Set tray BIPs

If selected, upon exiting the K-value screen, the program will go into selection mode and allow you to choose one or more distillation towers from the flowsheet. It will then present you with an input screen where you can enter a range of tray numbers and the BIP set that applies to that range.

Set Henry components

Select which components are to be modeled by Henry’s Gas Law K-values. All others will be modeled using the global K-value method. If checked, a upon exiting the K Value dialog a select Henry’s Component dialog appears. This option applies only when activity models are being used.

zjwmcl · 发表于 1970-1-1 08:00:00

那还是谢谢的啦。

IrisLove66 · 发表于 1970-1-1 08:00:00

重在参与，分享，总结 {:1106_362:}

chenhaijunsjy · 发表于 1970-1-1 08:00:00

就是想要这方面的

热力学设置，这个在chemcad中 help文档中就有，不过还想发一下。

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