What is P&ID?
P&ID is an acronym for Piping and Instrumentation Diagram.
Since it is a diagram, as a graduate chemical engineer (provided you are working or wish to work in the same field) you must know how to read, draw and review P&ID.
To make, read, interpret and review P&ID is one of the quintessential skills that you can learn.
In fact, most of the time companies may hand over some P&ID’s of past projects to you at the beginning of your professional career. In the hope that you can be in a position to handle and take charge of numerous diagrams and documents.
Graduate chemical engineer students are not well versed with understanding and working with P&ID’s.
As a part of the graduate course material, the only thing you come across is the primary difference between PFD and P&ID. You may learn more things about P&ID depending on the course module of your university.
What makes P&ID important?
That’s a real question. You must know as a graduate chemical engineer why it is so important. And with that, you will see why it is called as Piping and Instrumentation Diagram.
The fundamental objective of this diagram is as follows:
● This diagram is in a way a replica of the plant that is either to be erected, commissioned and run for a lifetime or it already exists. This diagram represents number of things about the plant facility but nothing as per scale:
1. Equipment
2. Utilities
3. Piping and fitting details
4. Instrumentation details
5. Control Loops
6. Offsite facilities
● This document is the primary document for detail engineering and number of other drawings and diagrams are made based on P&ID along with other documents:
1. To develop equipment list, line list, battery limits, etc
2. To make hookup diagrams.
3. To make single line diagram for power supply
4. Commissioning and Troubleshooting
5. Plant operation and maintenance
6. Risk Analysis
7. Operation and safety training
No matter what cap you wear under the roof of ChE or any other branch engineer, you will come across P&ID one or the other day.
Whether you work as a production engineer, safety engineer, process engineer, piping engineer, detail engineer, commissioning engineer, application engineer, or a third party consulting engineer, you must know – How to read, make, and review P&ID.
How to read P&ID?
As a graduate chemical engineer, you are expected to know how to read a P&ID. Learn to read before you can make one.
The intent of P&IDs is that it should reflect design, operation, maintenance and safety of the plant.
Knowing how to read P&IDs, allows you to understand better the design intent.
Understanding of process and interacting parameters helps to know about the process, and vice-versa, you can make better P&ID provided you understand the process and interaction parameters.
When you first see P&ID, you will come across number of symbols representing equipments, valves, instruments, pipelines, etc
Those symbols vary from company to company and client to client but only to an extent and for that, you must always ask or refer legends, for better understanding.
You can refer to Instrument Society of America (ISA) symbols for basic knowledge and usage.
You will see Tag numbers for various equipments and instruments. Line numbers for pipelines. Each line is with Type of Fluid, Size, M.O.C, whether or not Insulated, control loops with bypass line, etc
Whenever you read try to interpret the associated meaning with it:
● How and where safety relief valves are used.
● Standby Pumps and power supply.
● Drain and Vent lines.
● What symbols are used for different valves and instruments?
● Whether the instrument is field mounted, primary or auxiliary.
How to develop P&ID?
It’s easier said than done but to develop a P&ID is the most important task you can learn as a graduate chemical engineer. Learn to read before you make one.
Now that you have read some P&ID’s, you would have understood the basic philosophy of making one behind it.
Most of the time symbols vary because it depends on the client since each company has their rules.
P&ID originator needs to confirm and decide the symbol with the client at first.
Make a LEGEND of all the symbols used, so it is easy for a reader to understand.
The underline principle is simple and straightforward:
1. The plant must run smoothly and safely.
2. The plant must be safe enough for startups and shut down.
3. The plant must be safe to carry out maintenance. And that means each equipment, instrument, valve, etc. can be safely taken under maintenance or replacement if necessary.
It should follow:
IMSO: Installation, Maintenance, Safety, Operation.
One should keep all these points in mind before you make P&ID.
How to review P&ID?
It isn’t sufficient just to know how to read and develop P&ID. You will play an important role as a graduate chemical engineer by reviewing P&ID.
● All lines are sized, classified, and numbered
● All instruments tagged
● All set values of safety valves shown
● Standby pumps in place.
● Control valves and safety valves in place
● You should ask “What if.”
● You should verify whether P&ID is made keeping IMSO (Installation, Maintenance, Safety, Operation) conditions in mind.
If you are involved in a third party consulting or if you are working in an EPC company you may receive Vendor P&ID.
Vendor P&ID is by manufacturer vendor of the system or a package system (like a compressor, boiler system, etc.). There you have to review P&ID given by the vendor and may have to talk with clients to justify each thing mentioned or not mentioned in P&ID.
Wrap up – Understanding and handling of P&ID’s is a crucial part of any plant. Care must be taken at every step of it, right from the start of the project to the end of it, i.e. as long as the plant is in running condition.
Beauty of Chemical Engineering Principles
Beauty of Chemical Engineering and Underlying Principles:
There’s beauty in everything, sometimes it’s on the surface which anyone and everyone can notice, but sometimes it’s hidden, deep inside, very subtle.
It takes a different view to acknowledge it. And so, not everyone can see it, right on.
Many times, it’s not noticeable.
No. It’s not that, there isn’t any beauty, and hence, no one notices.
And neither the observer is incapable of observing and appreciating it. Perhaps you already see beauty in something else.
It’s just that the perception differs from individual to individual. And so, the saying goes:
Beauty lies in the eyes of the beholder.
I didn’t notice the beauty of chemical engineering principles until one of the faculty showed me.
She didn’t mention explicitly, but now I suppose that all she meant while sharing few examples while explaining the concept was – Not to bound the Chemical Engineering Principles only to its domain.
Discovering myself while standing on the shoulders of Giants:
Let’s not bound Chemical Engineering Principles – well, it might sound odd to read this, as you might think – what does it means or probably you know what I’m saying, either way, there’s something I would like to share few of my observation with you.
One Simple Question:
Have you ever travelled by train, a bus or any public transport? – apparently, at least, some point of your life or maybe even now you are on the go and might be reading this while commuting.
So?
So – What is the first thing you do as soon as you board?
I assume either of the two things may come to your mind – depending on the case. As soon as you board, you look around
1st: either for a place to sit or
if a seat is not available, you try to move yourself
2nd: to a less crowded place/point
Now, Can you connect this, to chemical engineering principles?
Of course, yes and here’s the analogy:
I can connect this either to fluid transfer or mass transfer because, the underlying principles in both are universal, i.e., HIGH TO LOW – now in the case of fluid transfer it’s from high pressure to low pressure and in that of Mass transfer, its concentration.
So the moment you are looking for a less crowded place – all you are doing is, shifting yourself from High (conc. / pressure– by other people/wall on your body, like, that of, the pressure exerted on the walls or the other molecules, in case, of Van der Wall Eqn ) to Low (conc. /pressure), isn’t it?
Or look at it, like this, you are looking for Local Optima!
Another example, which came to my mind when I had to wait for my cup of tea at a local tea shop.
My eyes observed something and mind started analyzing the whole process of making tea, and I concluded that –
● It was a batch process.
● Have raw materials and so the storage vessel for each raw materials: Raw-Materials like water, milk, tea powder. (These are transferred via pipe through pumps, compressor and other suitable mediums depending on the phase of the material and so forth)
● A Vessel to make tea (an endothermic process) – well, now you can imagine number of things happening inside the vessel from rising of temperature to mixing, forced circulation of stirrer, evaporation of water, leaching and if you are adding ginger or so extraction so on and on)
● Then Filtration: Solid–Liquid Separations.
● The transfer of product (tea), to a small vessel (in a Plant we have different storage tanks, one for daily/weekly and other maybe for monthly/quarterly or so) and then from a smaller vessel to a consumer (packaging).
Wait!
Was there any Mass and Energy Balance?
Yep, You guessed it right!
Without Mass Balance, the quantity won’t be as per the requirement (which is but obvious, if planned for 10 cups and if there is a mistake might end up for 5 or 15) and the quality will be affected by it too.
Energy (heat) supplied for the particular period is the energy balance.
This is what a process is all about. And then the things are stepped up to the next level from this point to the actual running plant.
So what I observed in this overall process was that the principles are inherently everywhere. Just a matter of awareness, observation and perception.
That’s the beauty of Chemical Engineering Principles, which I find it very mesmerising and to make it more beautiful I try to relate it now and then in different fields and for various reasons- maybe to find some solutions.
I try to see that subtleness that is present, which might go unnoticed at the first sight.
You are no more in the field, or want to shift because you are not working as aprocess engineer?
That’s the beauty of Chemical Engineering Principles:
You can apply these principles in any field!
For example, you no more want to be in the field or perhaps you want to be, but there isn’t any growth or there’s no money as it was earlier.
Tired of seeing your IT friends rising and your fighting against all odds for survival!
So you decided to shift to IT and that to the booming domain: Data Mining!
Data Analysis and or Mining!
Changing domain itself is very challenging, and top of that your new kingdom of Data Minning probably might make you go nuts. But let say you have decided and given a final verdict to your near and dear ones.
Now?
Will these principles of any use to you in your new journey of exploring your new kingdom?
Oh boy, of course! What do you doubt on?
We will just see on Overview basis; The similarity between the two so that you can think and can relate it.
Only Overview?
Yes, because Data Analysis or Mining itself is a huge field, of which I’m not a part of it at least so far.
Wiki says,
Data analysis is a process for obtaining raw data and converting it into information useful for decision-making by users.
Let’s dive deeper:
Data: as a mixture or a solution of Chemicals.
What do we do as Chemical Engineers?
Don’t you convert crude oil into products or different refined chemicals?
We use Thermodynamics to understand data (Chemicals) and their behaviour.
Let’s see for Data Mining: (Source: Dell.com/Software/Statistics/document)
The process of data mining consists of three stages: italics are from Source: Dell.com/Software/Statistics/document and Bold one is a comparison with Chemical Engineering.
(1) the initial exploration, (Process Synthesis)
(2) model building or pattern identification with validation/verification, and (Using Thermodynamics to predict behaviour and obviously we do modeling; don’t we?)
(3) deployment (i.e., the application of the model to new data to generate predictions). (Application of Thermodynamics for new reaction and separation (Chemical Equilibria) or Scale-up to make new product)
Please understand that both the fields have huge differences especially in applying mathematics in the hope of finding solutions but it was just a binocular view rather than the microscopic view to relate and find some similarity as to see the beauty of Chemical Engineering Principles.
There are many such examples which one can list out, or you can try to relate it to your own.
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