definition of MDMT value. how to find the right value for mdmt?

[ChriChri81]

goodmorning,

i 've some doubt about how a mdmt for a plant is calculated.
generally the client specifies the MDMT in his specifications, in this case we don't have any information about mdmt needed to design the equipments.
what informations we need to define MDMT?
the only parameter that we have in our hand is the minimum temperature of dry bulb, but we don't know if this value of temperature is the average of one day, week or month...Can you help me? Thank you. have a nice day.

Chri

 

[metengr]

ChriChri81;
You need to ask the client for temperature extremes regarding exposure to equipment and process conditions. You cannot guess at this.

 

[stanweld]

The Client, the Engineer (Process) and Jurisdiction (possibly) must provide the MDMT, assumming that you are the Manufacturer of a specific engineered pressure item.

 

[ChriChri81]

NO, i'm not Stan; We have "white paper" to define the MDMT for all the equipments.

 

[stanweld]

I assume then that you are the Engineer for the Owner and are responsible for determining the MDMT. The MDMT of a full scale operating facility need not be the least mean ambient condition unless the Jurisdiction requires that it be.

 

[metengr]

ChriChri81
There is something confusing with your OP. You have a white paper that what....defines what is MDMT? This is in most Codes of Construction.

You as the Engineer must decide on an appropiate MDMT and be able to defend it. The Juridiction may review your selection but they will not provide you with this information. You are on your own. If necessary seek help with this, it sounds like you are in over your head with PV design.

 

[imtiaz351]

On the basis of different cases/options, process simulations will be highlighted the Minimum Temperature of the process stream. For example, Blowout case is the stringent case for the minimum temperature of the stream that will pass through the associated equipments (like pressure vessel, piping etc) especially in oil & gas era and another instance is the minimum temperature of process stream of Refrigeration package etc. By the help of this input we can primarily select the material of equipment. Then after, further analysis/calculation of the equipment according to ASME Section VIII Div-1, ASME B31.3 etc, we can address the exact MDMT of the equipment.