To Clean Caustic Flakes Deposition Inside PFR

Your problem seems to occur from unreacted caustic in the reaction.

Possible undissolved or unreacted caustic flakes have the tendency to stick to the reacter walls.

How about going for caustic lye, which in liquid phase should be having minimum tendency to get deposited.

The other simple option to remove the caustic deposts ,is the use of hot DM water.You can add little amount of a surfactant to wet out caustic deposits.

I'm not an expert on this just taking a guess.

Have you looked into using clear chemical resistant piping. If you could find a suitable material, it would make checking it easy.

I used to use caustic flakes in another application. Is it possible to pre-dissolve the flakes in solution, before catalyzing takes place?

Hot DM water will dissolve it out. Passing a hot acidic solution such as citric acid will be even more effective. Remember to monitor the pH level carefully if you do this.

1. Check deposition with a borescope.

2. Scour caustic build up with an acidic agent, check again, flush with clean water when done. Beware of precipitate blockage during scouring.

Dear sir,

Thanks for valuable comment.

We make use of DM water after preheating it at a temperature of 90 Degree Centigrade .We also use sulfhaumic acid 0.01 concentration during circulation in reaction section.It is strong acid and our method is to neautralize the caustic by lowering down its pH to 7-8. In this course there is a use of huge quantity of DM water and time taken is approx 5-6 days. I wish to reduce the both.Boroscopy and pressure survey is performed at short and regular interval of time.Reactor capacity connected in series are of approx 80 Ton capacity.

Some method/arrangement/vendor if there is in your knowledge and you suggest will be highly appreciated.

Regards

So, you have an existing procedure

What are you trying to achieve?

We wish to reduce the time and use of DM water for cleaning by changing in our cleaning process/use of sulphaumic acid.

Use "normal" water for the bulk and then DM water at the end?

Is that 5-6 days the time it actually takes to do the clean or the service interval?

What about covering the inside of the pipes with a non-stick coating?

There are many questions you could answer that I could ask you, but you could save me a lot of time and effort if you dealt with it this way: assume I am competent in this field and tell me everything you think might be affecting the reaction, like what is the reaction, the reaction phases, the reagents, the catalysts,the solvents, if any, the desired reaction products, the side reactions, if any, with unwanted side products; and do not forget the range of temperatures for all parts of the system, including the starting temperature. The pressure is important also if it is not close to ambient.

Another important question is this: do you or can you disassemble the system to clear it? Also, what is the current clearing time used for, broken down into different processes? A mechanical description or the reactor system with identification of the wall compositions, especially a careful description of the shape of the fluid pathway through the reactor, connector, cooler, and receiver would be of great help. If you are ESL (English as a Second Language), I would suggest you write this out in your own language, then it be translated. You might find the answer yourself when you do this. May success be with you.

Thanks.

It worked and we got the solution for choking by side reactions due to change in Ethylene oxide composition.

Regards

Ashish prakash Vashishtha

Asst. Manager

India Glycols Limited

a.p.vashistha@indiaglycols.com

What worked? Summary please.

Sir,

As suggested/described by you to check the reaction kinetics and others, we get checked the Ethylene Oxide composition that is used in our reaction section and detailed data sheet was made covering past analysis and present.

We made some changes in columns running profile from where EO is recovered to match Past and present analysis.

Well that certainly clears it up...