2 replies to this topic

[Sarah_Process_engineer]

Hello Engineers.

 

I'm starting an optimisation study of the plant where I'm working trying to recover more condensate from the gas.

 

Could I please be helped with steps and procedures: how to start and what should I use as software, laws ... etc.

 

Thank you very much

[pavanayi]

The following steps will help you to start thinking in the right direction.

1. Make a proper material balance of the plant (including utilities like fuel gas and steam). You can use excel for this. You'll see that things don't add up, flow meters are not accurate, lab analysis doesn't match the composition analysis, etc. You'll have to accept some values and reject a few. Make a simplified PFD for your own use and put all the process variables onto it. (Pressure, Temperature, Flow). Be sure you are happy with the consistency of information.. This step will help you have a deeper understanding of your plant as well as will be useful when you need to do a process simulation model

2. Make a list of conditions the process has to meet (max C5 in LPG, RVP limit of Naphtha, etc etc). Compare the limits against what the plant is operating currently at. This step will let you understand what are the variables you can change in the plant.

3. Understand the current limits of your plant. This step is very important as ultimately any changes you propose should be achievable in reality. These will include things like 

    a. Flooding limits, spare condensing capacity, spare reboiler capacity etc in your columns

    b. Spare capacity in your fridge system (if you have one). This should include things like the compressor driver limit, condenser limit etc.

    c. Pressure drop constraints (if any)

    d. Utility constraints

    e. What are the current parameters stopping the plant from recovering more condensate?

    f. On the above topics, ask the plant operators why they have stopped at a particular value? what is stopping them from going further? Their response will provide you with further insight into the actual field operations and how it differs from the operation on paper.

4. After you have done the above steps, you should have a fair understanding of what is currently stopping the plant from recovering more condensate. 

5. Make a list of ideas that you think will result in improving condensate recovery

6. Use a process simulation tool to quantify the improvements for each idea in 5 above. (The material balance you made in step 1 will be very useful for this stage).

7. Identify any process modifications that are necessary to achieve the ideas you have in mind. 

8. Using everything you have understood about the plant, make a list of achievable ideas based on how much you can recover and how easily it can be done.

9. Rank the ideas as no investment, low investment and high investment.

10. Get another process engineer to go through what you have done and verify it.

 

That should enable you to think in the right path and generate/evaluate some good ideas.

[Bobby Strain]

The first step is to model your current operation. So you will need fairly detailed composition of the feed stream. Any of the process simulators are OK. So use the one you have access to. If you don't have one, you are greatly handicapped. Do that first, then get back to us. Best to plan and execute this first step before mapping out all the details.

 

Bobby