2 replies to this topic

[ing80]

Dear All,

i would like to know some information about the possibility to link Hysys with DCS.

i'm on site and we are building a plant. At this time we discovered that Gas cromatograph thaw we have bought not provide the Cp/Cv ratio. So to solve the situations we are investigating several solutions:

1) To build an algoritmic to calculate Cp/Cv ratio from Temperature, Compositions and Pressure directly on DCS. The problem is that the actual conditions are 40 barg and 90°C, so the ideal gas low are not applicable. I'm investigating on method to get Cp/Cv for real gas but is not easy.

2) To link Hysys with DCS. To import Data (Temperature, Pressure and Compositions) from DCS to Hysys, calculating Cp/Cv ratio in Hysys and to export the value from Hysys to DCS (everything in countinuos run).

I would prefer the second way and i hope that is possible.

We need to supply Cp/Cv ratio to Gas Turbine ( i understood that Gas Turbine uses this value to manage Air/fuel gas ratio but i do not sure).

Thanks all for your support.

Regars
Ing80

[PaoloPemi]

you can probably link a process simulator to a DCS but I would suggest to consider a less expensive alternative based on soft sensors, these are software packages which calculates many properties starting, in your case, from composition, temperature and pressure,
for example Prode has a soft sensor with both OPC and MODBUS interfaces which is compatible with almost all DCS systems, see

http://www.prode.com...hydrocarbon.htm

the standard version calculates these properties

Critical pressure
Critical temperature
CricondenBar pressure
CricondenBar temperaure
CricondenTherm pressure
CricondenTherm temperature
Liquid Fraction
Dew point temperature
Bubble point temperature
Gas heating value
Joule Thomson coefficient
Gas Wobbe index
Gas specific entropy
Gas specific enthalpy
Gas specific heat (cp)
Gas specific heat (cv)
Gas speed of sound
Gas compressibility
Gas specific gravity
Gas compressibility
Gas specific gravity
Gas density
Gas viscosity
Gas thermal conductivity
Liquid specific entropy
Liquid specific enthalpy
Liquid specific heat (cp)
Liquid specific heat (cv)
Liquid speed of sound
Liquid viscosity
Liquid thermal conductivity
Liquid surface tension

methods are the same of your process simulator and results are directly comparable (for example you can select a equation of state),
there are custom versions with different capabilities and features, I have used a custom version for estimating hydrate equilibria temeperature.

[ing80]

Thanks for your help,

the product is very interesting.....i'm investigating it, but we are at the end of
constructions of the plant and i think it is very difficult to add a tool like that because
we need to Client approval.