Methanol Storage 304SS vs Carbon Steel

[67prostreet]

Hello, my company currently incorporates a methanol injection system into our process lines during the winter time to keep them from freezing. Our current design incorporates a 55 gallon drum as the storage tank for methanol. This is a weak point in our refinery and we would like to use something stronger. from what i understand, Methanol is extremely corrosive to Aluminum making it a bad choice to use. 304 Stainless Steel is the preffered metal to be used, but its cost is far higher than a carbon steel. Do any of you have any information in dealing with methanol being stored in a carbon steel tank? Are there any coatings that the tank can be lined with to reduce corrosion, and what would its cost be? If at all possible, we would like to stick with a carbon steel body due to its low cost, but if this is not a feasible option, then 304 SS would be used. Thanks in advance for your help and knowledge!

 

[dcasto]

we use methane or nitrogen to blanket our methanol tanks made of carbon steel.

 

[EngAbdelkader]

Hi prostreet,
I don't think that carbon steel suffers any corrosion problem with methanol! in a previous post I've attached a file with a list of material/environment compatibilities you can take a look at it:

http://www.eng-tips.com/viewthread.cfm?qid=217762

the aluminum alloys on the other hand can suffer corrosion problem when in contact with methanol.

That's all my friend!

dcasto has already highlighted the safety issue regarding the storage of such a material! knowing that the low and high explosion limits for methanol are 6% and 36% respectively you should provide your tank with a blanketing system (even though using methane is a cheaper solution because of its availability in the refinery I would prefer nitrogen! but it's only a personal choice)

kader

 

[HEBERTJL]

Hi Prostreet,

We are every day buying tank transport equipment, and the choice of carbon steel versus SS is not only a question of initial buying price but also maintenance and reusability.

Even the lower grades SS offer much more advantages
than Carbon S. ie :

- no external paint
- better corrosion resistance
- better chemical compatibility
- easy cleaning
- easy welding ( in case of modification )

regards
Jean-Luc

 

[EdStainless]

Look into using a lean duplex stainless, like LDX2101. They are very strong so you can use much thinner walls than with 304. It is one less thing to maintain.
You can go CS, but you need zero moisture and zero oxygen (well very close to zero).

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