Outbreathing of nitrobenzine, aniline and similar

[shvet]

Hello forum
Someone having relevant experience - please advise

We are in engineering stage of a tank farm. N-methylaniline, aniline, nitrobenzene, benzene and methanol are stored in nitrogen blanketed low pressure tanks. Preliminary numbers are 4x1'000 m3 tanks, every tank is designed for storing every chemical mentioned.

Q1: Inbreathing is by N2 with O2 <0.5%v. Do we need premixing N2 with air to control O2 in the blanket lets say 5% to provoke inhibitor?
Q2: Nitrobenzene is unstable, tank has a large volume. How should we detect and manage hot spots?
Q3: Recommend drying and inerting method before / after maintenance / inspection. Water displacement is not the best one as we are limited in wastwater capacity. Cold nitrogen is the same is we have no source of liquid nitrogen.
Q4: Should outbreathing be disperced? Or treated? We have an incinerator in process site nearby but engineering contractor refuses to take vapors if those are not separated. We have bad communication, they told that have had an explosion of NB caused by ingress of a some other chemical and do not want having one more. Unlikely they provide more details. They require each vapor line shall be routed directly to burner.
Q5: Should vapor relief be disperced?
Q6: Mobile tanks unloading / loading balacing line - should we provide such?

I have no experience with such chemicals excepting methanol. Any help will be appreciated.

 

[LittleInch]

I can't think of many nastier chemicals so you can't free vent these.

If the incinerator wants it in separate lines then so be it.

)2 levels I can't say - you would need a materials man, but what sort of inhibitor are we talking about? your item 5 doesn't seem to make sense.

A balancing line makes sense for this sort of stuff. Horrible fluids.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[georgeverghese]

Q2) Nitrobenzene is a chemically stable compound, more stable than benzene. Aniline and n-methyl aniline would be much more reactive than benzene. Why are you having to heat the nitrobenzene tank ?
Q4)You may have to install a dedicated thermal oxidiser or incinerator, I think. The other process site may be dealing with fluids that may react with one or more of these chemicals you have.
Use pilot operated regulators for inbreathing and outbreathing to minimise leaks and reduce N2 consumption. Install a local LN2 vaporiser unit so you dont run out of N2. Otherwise, install an PSA type (carbon bed) inert gas generation unit that should give you 95% N2, on the condition that you have good quality compressed dry air generated with oil free air compressors.

Given the toxicity / reactivity of some of these chemicals, may be better to use above ground vessels rather than leaky bottom low pressure tanks that often contaminate local groundwater ( n-methyl aniline, aniline, nitrobenzene).

 

[JStephen]

Some or all of those may fall more into chemical engineering- check if there's a forum for that.

 

[shvet]

Thank you gentelmen, I will check and be back

It is repost from

https://www.eng-tips.com/viewthread.cfm?qid=513934

As I understood environmental forum is dead.