Removal of Oil from Condensate

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Anne from Little Britan
Anne from Little Britan
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Removal of Oil from Condensate

Post by csonics » Wed Nov 18, 2009 4:58 pm

Posted on behalf of fredrosse:

fredrosse
Just Starting Out


Joined: 26 Sep 2007
Posts: 19
Location: Philadelphia, PA USA
Posted: Fri Sep 28, 2007 6:22 pm Post subject: Removal of Oil from Condensate
Keeping Engine Oil out of the boiler is required, and there are several filtering schemes. It is my understanding that several of the newer "Oil Spill Cleanup" media is effective in capturing oil from condensate, but I have no direct experience with this.

Has anyone had good experience with filtering oil out of condensate, especially compounded steam oils which tend to emulsify with the condensate.

Thanks in advance for any help
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Maltelec
Site Admin


Joined: 23 Sep 2007
Posts: 156
Location: Cumbria, UK
Posted: Sat Sep 29, 2007 12:47 am Post subject:
When my dads boat was condensing we used some oil absorbing material. It worked very well despite only making a a temporary setup.

The best design I can think of would be to force the water from the condenser through the material (its a bit like cotton wool only not quite as soft) and then force the water to go down under a gate, so any oil which does escape will find it difficult to pass under the gate (like a traditional oil seperator).

This material would have to be changed when it is spent, so a good design would have this in mind.

I would have thought having 3 chambers where the water is made to pass through the material and then under a gate would clean as much oil out as you are going to get.

I am certainly thinking about the design I've stated above, the only problem I can see is if the material is permiable enough to allow enough water through without the differenticla being too great. If you require a 2" head of water to be able to force enough water through, that is 6" after the 3rd filter which reduces the hotwell capacity by a fair bit.

The material its self will make oil stick to it like it does to polystyrene, or like solder does to a metal braid.

I believe the other widly used type is effectively straw incased in porous material, so the water/oil will soak into the straw, the oil sticks to the straw and the water is then oil free. You could make a device which can hold straw in the path of the water, and even make it easy to remove to change the straw (which is then good for lighting the fire). As to its effectiveness in a hotwell, you can but try. A similar gate system would possibly help as well to catch any loose bits of oil.

Food for thought anyway.
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Edward
Lighting the Boiler


Joined: 01 Oct 2007
Posts: 39
Location: Ambleside, Cumbria, UK
Posted: Mon Oct 01, 2007 3:38 pm Post subject:
A system which I've had recommended is as follows: Imagine a chamber, it can be any shape but within reason the taller the better. Mounted in the centre is a mesh/strong chicken-wire cylinder around which is wrapped towelling. From the centre bottom of this cylinder is an outlet pipe either to the hotwell or to another similar chamber (but entering the second similar chamber outside the mesh cylinder). Oil and water enter the first chamber outside the central mesh cylinder and flow through the towelling which acts as a filter. As water is taken from the hotwell the level drops and water flows through the pipe in the bottom of the mesh cylinder to the next chamber or the hotwell.
I've been told that this system works well. The one seen by the person who recommended it to me (who is definitely a Very experienced steamboater) had three chambers and used kitchen paper towelling/tissue which went into the firebox when dirty. At the end of a longish days steaming the filter in the first chamber was filthy, in the second chamber it was slightly dirty, in the third chamber absolutely clean.
The advantages of this system are that it is relatively easy and cheap to make (even I managed it) The filter towelling/paper is cheap and it is easy to clean the filter or change the filter medium.
I'll try to let you know if mine works towards the end of next year!
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SLPegasus
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Joined: 09 Oct 2007
Posts: 2

Posted: Wed Oct 10, 2007 3:07 am Post subject: Removal of Oil From Condensate
This can be overcomplicated and need not be! My circuit has a feed water preheater which I stuff with cotton stockinette bought from a hardware shop on a 5m roll. Simply cut off what you need and allow the exhaust steam to pass through it-we have very little oil which manages to get past this! Then rig up a second filter (we use an empty extension lead cartridge which you fill will the bilge sock material) for cleaning any residual oil from feedwater-this just sits in the bottom of the hotwell and is obviously attached to the feedwater outlet. All you need then is a sheet of newpaper to float on top of the hotwel to keep things clean and tidy!
We change the stockinette every trip out and clean the secondary filter about once a month.
It is worth pointing out that we use Pegasus very much as a workboat and is in the water at all times working very hard, as a result you probably wouldn't need to give the secindary filter as much attention as us!!

Matthew O'Crowley
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