9 replies to this topic

[suresh2]

hi all,

Could you explain me.
what is the development of PFD's, P & ID's and UFD's ?

full form of PFD, P&ID and UFD ?

thanks a lot.

suresh

Edited by suresh2, 28 December 2009 - 03:07 PM.

[djack77494]

Suresh,
PFD's, P&ID's, and UFD's are among the most basic of the drawings or schematics used to depict a process, whether it be in the refining, petrochemical, chemical, power, or virtually any other industry. I'll add one other type of drawing, the BFD, and then describe each.

BFD or Block Flow Diagram is the most basic drawing type. Typically, it would show entire processing units as rectangles with lines drawn between rectangles to indicate major process flows between units.

The Process Flow Diagram (PFD) is just one step beyond the BFD in terms of complexity. Ideally, you would have one PFD for each of your major processing units. It would show the major equipment and controls. Typically the major streams are identified (e.g. by a number inside a diamond) which corresponds to a heat and material balance stream. The full mass balance table could be placed along the bottom of the PFD, or it may be placed on a separate sheet(s). The main purpose of the PFD, in my opinion, is to show the entire processing unit on a single sheet. Details are omited so that "the big picture" can be seen and understood. In pursuit of this goal, for example, a single pump symbol would often be used to represent multiple pumps in the same service. Basic process specifications for the main equipment are often listed. For complex units, it becomes difficult to show all that is needed on a single drawing, and multiple PFD's may be used to depict the process. (As you may gather, I do not favor that approach.)

I think of PFD's and UFD's or Utility Flow Diagrams to be essentially the same thing. UFD's would show the same type of information as PFD's, but merely geared to utility streams rather than process streams.

When you get to P&ID's, or Piping & Instrumentation Flow Diagrams, you're starting to approach reality. These diagrams identify the size and specification of piping and define the instrumentation requirements. All equipment is shown and identified on the P&ID's. Valves and specialty items are also shown. If you're doing a modification to an existing unit, then tie-in points should be shown. In this case, you should have two sets of the P&ID's - one for Demo (demolition) only, and one for D&C (or Design and Construct). Combined, these drawings define what is going to be removed and what is going to be added.

I don't want to imply that that's all there is or that you always have all these types of drawings. Drawings are routinely omited if not pertinent to the process. For largely mechanical systems, they sometimes use Mechanical Flow Diagrams in place of P&ID's. There may be Material Selection Diagrams showing materials of construction choices.

This is just scratching the surface of what's needed to define a complex processing facility. There are many other disciplines besides our own that produce their own drawings. So there are dozens of types of drawings that may be produced for a single facility.
HTH,
Doug

[suresh2]

Hi Doug,

Thanks for your time and great reply.

suresh.

hi all,

Could you explain me.
what is the development of PFD's, P & ID's and UFD's ?

full form of PFD, P&ID and UFD ?

thanks a lot.

sureshreddy asi.

PFD shows main equipment and lists Presure and temp. of streams (not lines.), for the main process hence Process Flow Diagram, UFD is same as PFD, but for Utilities (support process).
P&ID is detailed lines with pipe codes and operating temps and pressures. Has notes to explain stuff, has every line, and all equipment with tag numbers and so on

[Profe]

Hi

Sureh

About this subject, I think is useful to revise the next:

http://www.cheresources.com/invision/index.php?showtopic=1827

In this forum.


Fausto

Edited by Profe, 15 September 2011 - 01:51 PM.

[Cybick]

Hi all, Could you explain what is the Process Data Sheet amd Material Selection Diagram. And one more question what is Document Control Index.
If you have could you show me examples of these docs. Thanks you in advance.

[Cybick]

What is the difference between plot plan, layout drawing & key plan?

[denizen360]

pfd means process flow diagram and p&id means piping and instrumentation diagram.
PFD will give an overview of the plant process and what are the various units present in the plant..
Each unit is represented by p&id, from p&id we can understand wat are the instrument prresent in the plant and process related information like temperature,pressure, etc... standard symbols are used for drawing p&id
read this article: how to read a p&id

[djack77494]

After not adding to this topic in over 5-1/2 years, I thought I'd go ahead and add some other thoughts for these most important products of process engineering.

There are many different ways of depicting those things we wish to show on process-oriented drawings. Despite attempts to reach concensus, you will very seldom see two organizations with the same approach and symbology, especially as you move to the level of detail shown on a P&ID. In particular, I'd like to offer up my opinions to the two most important process drawings in our field. Specifically, I'd like to do a sort of compare and contrast between the two.

Process Flow Diagrams (PFD's) should schematically define the process. In conjunction with the heat and material balances, they depict in fair detail what happens within the process. One can also glean the process conditions, the order of processing, and the "duties" of the various equipments throughout the process. (Here I am using the term duties rather loosely.) I feel strongly that the PFD should be geared to show process information such as vessel capacities and residence times, exchanger and heater duties, etc. The PFD should be a "one stop drawing" for getting an overview of how the process works. Spare, auxilliary, and minor equipment should NOT be shown since showing anything that does not enhance one's understanding to the process will dilute the utility of the drawing. If at all possible (and it is always possible in my opinion), a process unit should be shown on a single drawing. Failure to depict a complete processing unit on a single drawing enormously diminishes the drawing's value. I would freely simplify what is and is not shown so as to enable this objective. The most important controls in the system should also be shown, but in a form that is simplest to depict. Thus if it's important to show a level control system that is actually used to reset a flow control system (i.e. cascade control) depict the controls as a level controller modulating a level control valve. That's enough to get the idea across.

In contrast, the Piping and Instrumentation Diagrams (P&ID's) evolved from mechanical drawings and should show as much of the mechanical equipment as possible (i.e. all of it if possible). Important mechanical information should be presented. For example, a typical shell and tube heat exchanger should have its length, diameter, TEMA type, and design conditions stated. Heat duty should NOT be included in the P&ID because it is strictly process information, independent of the mechanical equipment. I like to show and identify all mechanical equipment and all instrumentation on the P&ID. Here, perhaps more than anywhere else, practices vary widely as most organizations will condense the way instrumentation is depicted. Because the P&ID's can be burdened with "excruciating detail", I like to use references to details for minor hardware that can benefit from a more simplistic depiction and that is repeatedly done in the same or very similar fashion throughout the unit. Control system logic can be shown in other types of drawings and merely referenced in the P&ID's.

I'm in a bit of conflict concerning how important it is to accurate depict arrangements within a P&ID. On one hand, a P&ID is a schematic, which implies that a certain amount of "artistic license" is allowable. And they are not drawn to any sort of scale. However, to the degree possible, I like to show configurations as they actually exist (or will exist). So if I have a hot diesel product stream entering the top of a S&T exchanger and leaving the bottom on the opposite side, I try to show it that way. That's not always practical, but I personally demand to have a reason before depicting things in a way that could lead to confusion or misunderstanding. If I really do have a very busy drawing that would get even more so if I attempted to enforce these standards, then I might grudgingly relax those requirements. In no case, however, should you alter (corrupt) the depiction of your system without due cause.

I welcome any additional thoughts you might have on this topic. It seems to me that many process engineers get overly focused on (what may be thought of as) glamorous topics such as modeling, reactor design, and distillation topics while neglecting topics such as the above. This is, however, our "bread and butter" and I daresay that many more productive process engineering manhours are devoted to our drawings than to other more esoteric process topics.

Edited by djack77494, 14 September 2011 - 03:54 PM.

[aba_aci]

Suresh,
PFD's, P&ID's, and UFD's are among the most basic of the drawings or schematics used to depict a process, whether it be in the refining, petrochemical, chemical, power, or virtually any other industry. I'll add one other type of drawing, the BFD, and then describe each.

BFD or Block Flow Diagram is the most basic drawing type. Typically, it would show entire processing units as rectangles with lines drawn between rectangles to indicate major process flows between units.

Sorry djack 77494, i don't mean make negative rating reputation, i mean on the contrary, but i was wrong choose icon . but, i can't back to the choice.

sorry to make you uncomfortable