3 replies to this topic

[Saintoluseyi]

Please my people, I am trying to produce ethylbenzene by alkylation of benzene with ethylene using Hysys, but I don't know how to go about the simulation and it's my final year project, I don't know what process route or conditions of the unit of operation involved, please help me.

[Bobby Strain]

Well, you need to conduct some research to begin. You can't simulate a process you know nothing about. Good luck.

 

Bobby

[Saml]

I'll tell you a story

 

When I was young and doing my final project (around 1992-93) , I too started to use Hysys. At that it was from a company named HyproTech and ran on  DOS (text) screens on amber or green monitors. We worked on a 80486 machine at nigth, because on days professors and investigators had priority. I've been from 10pm to 6 am next day running it... And the license key was plugged into a RS-232 port and an electrical socket. I guess it used around 20 Watts for the license device only.

 

Later, I went to my first job, were they used Pro II (then Process), that had to be programmed in text files, and then we switched to Aspen that had that revolutionary graphics interfase.

 

I was a fan of simulators when I had my first "serious" assignment. We had an alkylate plant not running for several years because of lack of custormers. Commercial people were working on a deal with a refiner, and apart from a plant inspection, the company planned a test run before signing a firm contract.

 

I started by building a simulation of the alkylate unit based on drawings and original PFD. It took me about two weeks. My supervisor saw what I was doing but said nothing. Two weeks later, with ony two before the test run, he called me and asked several questions:

 

-¿What do you plan to see?

-¿What will be your criteria to determine that plant ir running fine, or is reaching a limit?

-¿How will you know that a particular equipment is running fine, specially the contactor?

-¿What is the important data to collect?

-¿Are you sure that Maintenance checked the instruments that are important to you?

-¿What lab analysis will you request?

 

The next two weeks were probably the most intense of my career with 70+ hours each week. I only used the simulator to verify the efficieny of one column that did not look right. That is, almost useless.

 

Now, 25 years later I can tell you that the best advice is the one that the previous poster gave to you. I've been there, done that, and failed. Please understand that simulators are just a sophisticated calculator and not much more. It will give you nothing if you don't know what you are looking for. So first, dedicate time to elaborate the right questions to feed to the simulator. I know that it is usual in undergraduate project assignents to request "a simulation of the process". Do it at some time if you need to comply, or if it is useful, but not at this point.

 

Now, going to your specific question:

 

You are lucky. Ethilbenzene nowadays is a nice process (35 years ago, with the aluminum chloride process it was a horrible one. Operators in the company I worked for called it "ethylvenom")

 

You can check in Ullmann's Encyclopedia. I've seen the abstract and all the major technologies are there. It will be a good starting point

http://onlinelibrary...10_035/abstract

 

If you seach in Google "ethylbenzene processes" you have also results to look at like these videos

 

www.youtube.com/watch?v=Ufy2IqDPGhk

www.youtube.com/watch?v=6rqrL87FZa4

 

They are not totally what you want but will give you an idea of what the process is about

 

This one that will help you when you decide to model

http://www.diquima.u...etilbenceno.pdf

 

Or you can search patents for flowsheets,like this one

https://www.google.c...tents/US7517506

 

 

You should seek to have an ansser to at least these questions:

 

- What catalyst do they use

- Is the kinetic available (probably not)

- Can I found a design criterion (like LHSV) to size my reactor?

- What are the main subproducts of the reaction?

- What do you do with them?

- Are the reactions reversible?

- Are the reactions endothermic or exothermic?

- Where do the impurities in the feed go?

- What are the typical pressure and temperatures? Why?

- What are the typical plant capacities being built in the last 10 years?

- Who are the technology suppliers?

- What are the pros and cos of each technology?

- What capacity and what technology shall I use for my plant?

- What are the raw materials and product specs.

 

You can start thinking in a simulation only when you have answered these questions, and already made a preliminary process diagram on paper to orient yourself. Then a simulator may tell you how much heat you need to remove and where, how many trays a certain column should have, or can be of help for sizing a valve or exhanger.

 

Regards

Edited by Saml, 13 May 2017 - 11:27 PM.

[Saintoluseyi]

Thanks to you guys,I will follow the advice and am sure I will get it done,am really grateful