2 replies to this topic

[akezero]

Plaes help me, where I can find PFD(Process flow diagram)and PID(Pipeline and Instrument diagram) which have instruction? I'm finding in google.com and another search engine website but not found.
what can you give me a recommend of my search to find this PFD and PID
Thankyou very much

[Art Montemayor]

akezero:

Presumably you are a student. This is a Forum dedicated to helping students. I’ve been helping students on this Forum for some years now and I will try to help you. However, don’t assume that you are going to obtain what you ask for. Remember, you’re the student and what you’re about to read may not be to your liking. But it’s meant to help you, not to destroy your chance of becoming an engineer by giving you so-called “magical” answers that will eliminate all the hard, tedious work being asked of you. There are no magic answers.

The best way to help you is to point out that there are normal, conventional ways that all Chemical Engineering students are taught about process design and process technology: you have to take a course (or several) in the matter. It is there that you are introduced to textbooks and Handbooks where example and actual PFDs are given. Some of the PFDs have a mass balance shown. I still have my old Shreve Text (“The Chemical Process Industries”) and others. Hydrocarbon Processing Magazine also published (and I believe still does) a collection of most of the petrochemical process PFDs. My point in all of this is that the Internet is very new. We Chemical Engineers got all this information (and more) in the past from libraries and journals long before the personal computer was available around 20 years ago. Use a library – preferably your university’s technical library for the information first. Do a library search.

The most important item I can teach you is that you shouldn’t come to experienced individuals who have been “around the block more than once” with illogical or extraordinary requests. Don’t forget: we know already what you are going through and we also know what is expected of you if you are to LEARN. The truth is that as a student you’re supposed to study. And to do that, you have textbooks and professors who introduce you to what you are supposed to know and learn. When you receive a class project – like a process design problem – you are not just blindly thrown into the proverbial “Lion’s Den”. It may seem like it; but that’s not true. You are expected to react to what you’re challenged with by using the tools that have been taught to you. There are some things that may not be explained to you.

There are no published, credible P&IDs available publicly. If you can obtain one, it is probably illegal or pilfered. The only reasonable and logical way to obtain a process P&ID as a student is to generate one – pure and simple. Ask any professor and he’ll confirm what I say. A short, but excellent reply by Guidoo, a sharp and experienced engineer who contributes a lot to these forums, is in one of the threads in this forum. It essentially replies to the same request for a PFD.

Why are you asking for a PFD when you haven’t even defined the process and its conditions? There are many PFDs for a variety of the same chemical. Do you intend to produce Acetone by fermentation or by sythesis, using hydrocarbons? Which process do you mean? And what if you did get a PFD; what good would it serve you if you don’t have a mass and heat balance with it? Very little, if anything.

Now, lets get to the heart of the matter. As a student you’re supposed to organize the design of your project. You have been instructed in the basics and you should be able to write an outline of your scope of work as the project is supposed to come together. Roughly, you should do the following in more or less the following order:

1. Select the process and define all the essential parameters, like catalyst, process conditions, type of equipment, capacity, utilities, etc.;
2. Generate the stoichiometry and define the Unit Processes and Unit Operations involved. You should know the input and output of the key units or pieces of equipment;
3. Generate a Process Flow Diagram that illustrates the various steps and major equipment in your process;
4. Calculate or simulate the process, obtaining a credible and checked mass and heat balance that verifies what you are designing;
5. Revise your PFD with a table of all the major streams and pertinent heat balances; have a peer check to make sure all mass and heat balances out correctly.
6. Make a logical and rational decision on how you will control the process as to turn-downs, start-ups, shut-downs, safety concerns, quality problems, etc.
7. Make all the major and critical calculations involving the sizing of all the major equipment and piping; this is the long, rough, and tedious part that requires a lot of hard calculations; some of it may have already been done by simulation;
8. Generate a P&ID showing all the equipment and piping, together with all the indicated sizes.

As you can see, the P&ID always is the last major item on the list. What in the devil do you want with a P&ID (“the answer”) when you haven’t done all the pre-requisite work? You don’t start with the answer. You start with what’s given you and generate the answer.

My advice is to give up on ever getting a P&ID for your process. P&IDs are considered the “document of record” – i.e., the one document where all pertinent and important details are to be found. It takes millions of $$ to generate a real one. It would be very stupid of any chemical producer to allow the P&ID to be stolen, “borrowed”, or removed from his property for use by a student. This is a very serious act and totally illegal in most or all countries.

A simplified PFD (devoid of any mass or heat balance) is as much as you can hope to obtain from others – if you name the specific process that you are talking about (and its raw material). And this you can find in literature, if it has been done by others in the past.

I hope this helps to orient you in the right direction. Let’s face it; you have a tough job ahead of you. Don’t make it any tougher by thinking that you can get by with a minimal of effort and getting the “answer” from others. If anything is worthwhile going after, it isn’t going to come free to you.
Good luck.

Art Montemayor