I have problem with the word 'parts' here. I don't know if 'layers' would have more sense, but I am not sure that the author is talking about layers.

Parts in the oil in the form of an emulsion are separated by breaking the emulsion by both, deemulgator and the procedures of draining and desalting. For neutralization of the oil acids, after desalting devices, a dissolution of sodium base (Na2CO3 or NaOH) is added.
The two parts of the emulsion are technically called 'phases'. There will be water and oil mixed together which forms an emulsion. After treatment it hopefully settles out into two separate layers which can be separated by draining the bottom layer (which will be the water) away carefully to just leave the oil in the tank.

So :
The oil in the form of an emulsion is separated ino its two phases by adding both deemulsifier and salt. The aqueous phase is then separated off by draining. Subsequently the acids in the oil are neutralised by the addition of an alkaline sodium solution.

Two additional notes -
1. I've never heard of a deemulgator and it only comes up on a Google search in notes on what I assume are from Eastern European scientific reports of a similar process. I would use the term deemulsifier but if your sources indicate that this term will not be recognised by potential readers of your translation, you'd better stick with deemulgator.

2.I've changed the word 'base' to 'alkali' . It means the same, more or less, in Chemistry and it's more appropriate here.
Thank you Alan very much.

What would be the correct term for base oil then?
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Context again!!! It can mean lots of things just as two words.

By the way I've misspelled 'into' as 'ino' in the text above.

Sorry, it wasn't base oil, but 'base petrol':

Alkylation process (1941) enabled the production of airplane petrol. Further development of the technological processes enabled qualitative and quantative satisfaction of the present demand for petrol and diesel fuel, as well as for base petrol and gas-like hydrocarbons as raw materials for petrochemical industry.
Quantitative!!! not quantative

'Base petrol' in that sentence doesn't make a lot of sense.

I guess that the author means:-

- for both liquid and gaseous hydrocarbons as raw materials -

or more technical .-

- for low-molecular weight hydrocarbons as raw materials-
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Dear Alan,

I don't know - I've translated it (base petrol) literally. I'll have to ask the author.

Thank you very much for your help.