## Dew point software cricondentherm natural gas hydrocarbons excel matlab gas density units

Prode Properties has specific methods which permit to calculate dew points, bubble points, *equilibrium points* at specified phase fraction (vapor, liquid, solid **) and pressure (or temperature), typical applications include hydrocarbons dew point (HDP, HCDP), cricondentherm, cricondenbar of natural gas mixtures from gas analysis.

Prode Properties can calculate up to 5 **equilibrium points** along a line with specified phase fraction, in addition there are specific methods for calculating directly Cricondentherm, CricondenBar and Critical points. With Prode Properties you can do this in Excel, Matlab or any compatible application including custom software, this example shows how to use these methods in Excel.

Properties includes a Stream editor which permits to access all informations (as compositions, operating conditions, models, options) for all streams which you need to define, to access the Stream editor from __Excel Properties__ menu select Edit Properties

The Stream editor includes several pages, from the first page you can select a stream (Properties can store all the streams required to define a medium size plant) solve a series of flash operations and see the resulting compositions in the different phases, in this page select the stream you wish to define, for example the first.

Finally we must save the new data, in the first page click on "Save" button, note that you can redefine the name of the stream as you wish (editing the cell near the button "Save"), you can define / modify many streams following the procedure described.

here you can select the units which you need for a specific problem, in this example for the pressure (first row) select Bar.a , notice that unit for temperature is K (but you can set the units which you prefer) then click on Ok button to accept new values and leave the Properties editor.

Now you are ready to use Properties for calculating all the properties which you need, however there is still a last thing to do if you do not wish to lose all data when leaving a Excel page, precisely to save data to a file, to save data to a file from **Excel Properties** menu select "Save a Archive"

then select the file "def.ppp" if you wish that Properties utilizes this data as default (this is the normal , recommended option), differently set a different name (you can for example define different names for different projects) but you will need to load that specific Archive before to make calcs for that project and since Excel reloads Properties with any new page this may result tedious…

Suppose we wish to calculate a equilibrium point near the __critical point__ for the mixture defined in stream 1, to get the first critical point pressure we enter the macro =StrPc(1,1) where (1,1) refers to the stream 1 and first **critical point** detected, we enter this macro in B1, in B2 we enter the macro =StrTc(1,1) to calculate the critical temperature in the same way, in cells B3 and B4 we enter the macros = StrCBp(1) for CricodenBar pressure and = StrCTt(1) for CricodenTherm temperature, with this data we have a plot of the whole phase envelope.

where the first value (1) is the stream , the second (cell B1) represents the pressure, the third (0) is the phase fraction (with 0 we specify 0% liquid or a point on dew line, the same would be by setting the state as gas and *phase fraction* as 1.0) the fourth (1) is the state (in Properties 0 = gas, 1 = liquid, 2 = solid) and the last is the required position (we require the points 1-2 along the dew line)

Observe the dew line, the red line below the critical point, there are up to three different equilibrium points at the same temperature (the area around 190 K), if you add the saturation point on the bubble line (black line) we have a total of four saturation point pressures at a given temperature, to calculate the points on the dew line we use the method:

where the first value (2) is the stream which we defined, the second (cell B1) represents the temperature, the third (0) is the phase fraction (with 0 we specify 0% liquid or a point on dew line, the same would be by setting the state as gas and phase fraction as 1.0) the fourth (1) is the state (in Properties 0 = gas, 1 = liquid, 2 = solid) and the last is the required position (we require the points 1-3 along the dew line)

where 2 is the stream, B1 represents the temperature and 0 is the (liquid) __phase fraction__, notice that you?ll get the same values as for the first equilibrium point in PfTF(), by changing the specification we can use the method LfTF() to calculate the point on bubble line