Curious white powdery deposit

[Michael GilliganParticipant @michaelgilligan61133]

Forum members may recall that I had some ‘adventures’ a while back, with the Apollo oil-level gauge for my central heating.

Today, I removed it from the tank to check the internal battery, which appears to be fine … and I noticed a deposit accumulating on various plastic surfaces

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Any ideas what the substance might be ?

… presumably something is evaporating from the kerosene and then precipitating.

Having cleaned much of it off, I re-fitted the sender to the tank and the reading is unchanged.

Nothing important … just curious

MichaelG.

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Ref. __ there is a copy of the Apollo instruction leaflet in my Documents Gallery

 

[JAParticipant @ja]

We used to be plagued by this white deposit at work. It would get deposited on many surfaces including fuel sprayers and injectors. It never caused any problems.

Occasionally an engineer new to the job would get the labs, who had more important things to do, to find out what it was. It was always Calcium Carbonate, lime scale.

JA

[David JuppParticipant @davidjupp51506]

Could be a hangover from ‘Caustic Wash’ of the Kerosene during production, depending on the quality of water used in the wash, it can contain some dissolved CaCo3.

[Michael GilliganParticipant @michaelgilligan61133]

Thanks, both

MichaelG.

[Martin King 2Participant @martinking2]

Hi All,
I came across all sorts of curious white powdery deposits during my 25 odd years in the film industry doing music videos, and commercials late into the early hours, fortunately a good cup of tea kept me going! 😀

cheers, Martin

[Michael GilliganParticipant @michaelgilligan61133]

Ello, Ello, Sir … I understand you are in possession of certain substances … etc.

🙂 MichaelG.

[David Jupp]

On David Jupp Said:

Could be a hangover from ‘Caustic Wash’ of the Kerosene during production, depending on the quality of water used in the wash, it can contain some dissolved CaCo3.

I have often wondered how water came to be dissolved in paraffin/kerosene, domestic or aviation. What is the “caustic wash” used for? Is it part of the process to remove sulphur? I assume it is neutralising an acid. Also, is it used on petrol?

JA

[David JuppParticipant @davidjupp51506]

JA – I only found that snippet, by searching the web.  I came a cross a research paper looking at optimising the Caustic Wash process, which gave details including levels of CaCO3 in the wash water.

The Caustic Wash is used to meet acidity specifications.  It seems it is often used early in the refining process, so wouldn’t be a surprise to see the effects of it in any downstream products.

There are plenty of ways for water to get into fuel.  Crude oil can include ‘produced water’ direct from the well.  Water can be used in refinery processes, or in routine cleaning of equipment. Storage tanks ‘breathe’ and atmospheric water vapour will condense out.  Poor installation or poor maintenance for underground tanks can allow water ingress.

Now that petrol contains some ethanol, it will hold more water than was previously the case (bug growth in storage tanks has become much more of an issue since the routine addition of biofuels to petrol and diesel).

 

[Andy_GParticipant @andy_g]

I think it’s a given that there will be water in the kerosene – from run-down from condensed water vapour in the air space if nothing else – and there will be diurnal evaporation / condensation cycles for water vapour inside the tank.

However, even if the water contained residual CaOH or CaCO3, it’s still a mystery to me how either of these could make their way to the top of the tank from the kerosene.

Neither CaOH or CaCO3 can be carried by water vapour. If the deposit is indeed CaCO3, could there be some volatile calcium compound (organic?) that is also evaporating from the kerosene?

In theory, at least, this could re-dissolve in the condensation that forms at the top of the tank and possibly react with CO2 from the air to form the deposit, but I’ve no idea what such a compound could be.

[Author]

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