In data 1 ottobre 2013 si terrà presso l'aula magna della SEDE DI TARANTO il passaggio di consegne dal vecchio rettore Prof. Ing. Nicola Costantino al nuovo rettore Prof. Ing. Eugenio Di Sciascio.
A seguire ci sarà un seminario sulle valvole di regolazione per servizi "severi" tenuto dal Dott. Ing Fabio Giove, ex studente di questo Politecnico ed attualmente Technology Director presso l'azienda IMI Severe Service / CCI Italy S.R.L.
PROGRAMMA DEL SEMINARIO "SEVERE SERVICE CONTROL VALVES".
• What defines severe service control valves?
There is a Control valve hierarchy, that correctly applies to certain condition of
operations. The simplest is the butterfly, then follows the ball valve which is an on
off valve, that most of the people are trying to transform into a control. Real control
valves are plug or cage guided control.
• Severe service definition
What defines a service severe and what kind of valve to use? First of all, it is
required to define the Application Definition. This is, it is necessary to Know in what
type of plant the valve is installed in. In general, we should:
– Identify the function of the control valve in the loop
– Review data sheet and establish operating parameters based on:
• Specified operating conditions
• Extrapolation between specified conditions
• Historical knowledge of the valve application and industry
When there are Issues with cavitation and noise, then the service is extremely
severe. A failure can potentially create a loss of production, therefore we must
understand the startup time of the process and how much problems it creates a
shutdown for a non-planned maintenance. Different industries have different times
for start-up or shutdown, which may increase the severity of the service. An
example
• Power plant start-up is 3-4 hours
• Refinery start-up is 1 week
• Waterflood program may take 1+ year. A loss of time can
be hardly recovered.
In some industries the fluid may be more corrosive, because Fluids may contain solid
particles, or the flow and the process require High pressure drops or Two-phase
flows. In this cases, the failure is associated with a mechanical erosion or crack of
components.
In general, the severity of the application is normally associated with a common
Root cause: the excessive trim exit velocity. I will analyze what is the Velocity
control principle and how is this applied to Single stage pressure drops or multiple
stage pressure drops. For this reason it is essential to calculate the proper speed of
the flow in the different areas of the valve.
