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Topic: dissolution of gases in mineral oils  (Read 2172 times)

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Offline andymarin53

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dissolution of gases in mineral oils
« on: October 12, 2015, 11:05:38 PM »
Hi buddies,  :)

I'm working on the dissolution of some hydrocarbon gases in mineral oils. I understand that one of the mechanisms involved in the dissolution of gases in liquids is the Henry's law. The situation is that I am designing the experiment for dissolving acetylene. I have a very simple idea for doing this, I am planning to introduce 25 ml of mineral oil and 25 cc of acetylene in a 50 cc glass syringe. Once having this arrangement, I want to subject the plunger syringe to a pressure for 24 hrs in order to dissolve the acetylene in the oil. Then, I will drain the no dissolved gas in the oil, and by using degassing methods and gas chromatography, I pretend to find that the acetylene in the chromatogram
I would like to have some opinions about if my experiment will work.  ;D

Offline mjc123

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Re: dissolution of gases in mineral oils
« Reply #1 on: October 13, 2015, 05:18:21 AM »
You are aware of the dangers of using acetylene under pressure? E.g. from https://en.wikipedia.org/wiki/Acetylene:
"Acetylene is not especially toxic but, when generated from calcium carbide, it can contain toxic impurities such as traces of phosphine and arsine, which give it a distinct garlic-like smell. It is also highly flammable, as most light hydrocarbons, hence its use in welding. Its most singular hazard is associated with its intrinsic instability, especially when it is pressurized: under certain conditions acetylene can react in an exothermic addition-type reaction to form a number of products, typically benzene and/or vinylacetylene, possibly in addition to carbon and hydrogen. Consequently, acetylene, if initiated by intense heat or a shockwave, can decompose explosively if the absolute pressure of the gas exceeds about 200 kPa (29 psi). Most regulators and pressure gauges on equipment report gauge pressure and the safe limit for acetylene therefore is 101 kPagage or 15 psig.[34][35] It is therefore supplied and stored dissolved in acetone or dimethylformamide (DMF),[36] contained in a gas cylinder with a porous filling (Agamassan), which renders it safe to transport and use, given proper handling. Copper catalyses the decomposition of acetylene and as a result acetylene should not be transported in copper pipes. Brass pipe fittings should also be avoided."
25cc doesn't sound much, but where's it coming from?

Offline andymarin53

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Re: dissolution of gases in mineral oils
« Reply #2 on: October 13, 2015, 12:13:10 PM »
Thanks mjc123, for the opinion about of the potential dangers of using acetylene, it is really helpful. However, I am thinking about to get the gas from a cylinder because it seems the easier source, besides I don't need too much gas so that it is possible to request for a bit to one of the chemistry labs at my university. On the other hand, the pressure I want to apply is about 2 ATM, because the aim of doing all of this is to simulate the conditions in which some gases dissolve in mineral oils used as dielectric fluids in power transformers. This gas, among others, are generated and dissolved in the insulating oil, that is why the DGA analysis is used to diagnosticate the operative status of the transformer.

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