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-   -   Propane oil? (https://www.irv2.com/forums/f59/propane-oil-471029.html)

PSOUZA 12-20-2019 04:05 PM

Quote:

Originally Posted by StorminNorma (Post 5080699)
We had to load a syrupy liquid called mercaptan into the flow when filling the transport. :D




The mercaptan is actually a light liquid,with a density of .8, thinner than water. It becomes a gas at about 95* F so it is mixed in a carrier liquid to bind the mercaptan and make it more easily handled. This carrier is readily dissolved in the propane and becomes part of the heavy ends distillate.


Phil

remusr 12-20-2019 06:44 PM

Normal to find some oil in a propane tank and is not a problem with refrig or furnace orifices. It can foul the tiny orifices and regulators used in our small bbq's though.

A small amount of low viscosity oil is injected in the propane after processing to lube valves & orings etc that would otherwise be dessicated, since Propane is dried out to at least -40F/C at bubblepoint pressure so it can be used in the winter and also not rust the carbon steel containers it is stored in, like your bottle. If you blow out the tank the oil will be blown out too.


Mercaptan is a sulfurous stench used to...stench the otherwise odourless propane and natural gas fuels to make leaks obvious. A safety measure.

mgnorris 12-21-2019 06:32 AM

I keep seeing posts on here to ďblow the propane out of the tankĒ. I donít think you people realize the extreme danger in doing that. Liquified petroleum gas, LP. For short, expands by 240 times its compressed volume when released into an atmospheric pressure area. One gallon will create a cloud with enough explosive force to level a house. I have, while working in this industry, witnessed a very large explosion caused by negligence. Itís not something that anyone would ever want to see firsthand. NEVER release the contents of an l tank into the atmosphere unless you are qualified to do so. And never release the tank inverted. Liquid propane boils at -34 f. Itís heavier than air, so it will lie on the ground, seep into cracks, and be there for longer than you realize.

lwmcguire 12-21-2019 07:19 AM

This has been interesting to follow

Since most of the applications discussed use vapor taken off the tanks instead of liquid from a low point or tube it is quite notable the amount of oil mentioned

We ran propane trucks and tractors back when we paid 5 cents per gallon for semi load deliveries for many years

Liquid with heated vaporization on vehicles

All buildings and cooking was in LP as well

Never an oil problem ever

Motors did have propane filters and of course just like natural gas installation all drip legs were in place

PSOUZA 12-21-2019 10:38 AM

Quote:

Originally Posted by lwmcguire (Post 5081796)
This has been interesting to follow

Since most of the applications discussed use vapor taken off the tanks instead of liquid from a low point or tube it is quite notable the amount of oil mentioned

We ran propane trucks and tractors back when we paid 5 cents per gallon for semi load deliveries for many years

Liquid with heated vaporization on vehicles

All buildings and cooking was in LP as well

Never an oil problem ever

Motors did have propane filters and of course just like natural gas installation all drip legs were in place




These discussions tend to amplify the oil and contamination problems in propane out of proportion to what is actually occurring because most of those concerned have not even the minimal preventive measures in place.


A drip leg, properly positioned and maintained, would eliminate most all the problems.

Lots of distractions and inaccurate speculation on things that are not remotely understood by those participating in the discussions, on a problem that can not be removed from the system, but can be managed by proper means.

More emphasis on the management methods should be introduced to the discussions, and less fantasy.





Phil

PSOUZA 12-21-2019 11:23 AM

Quote:

Originally Posted by lwmcguire (Post 5081796)
This has been interesting to follow

Since most of the applications discussed use vapor taken off the tanks instead of liquid from a low point or tube it is quite notable the amount of oil mentioned

Liquid with heated vaporization on vehicles

All buildings and cooking was in LP as well

Never an oil problem ever

Motors did have propane filters and of course just like natural gas installation all drip legs were in place




The oil problems are variable, by region, and possibly by season. Caused largely by the shipping methods, after refining.


Reliable observations on actual amounts of oil recovered are scarce.


Drip legs don't seem to be common on RV's.
https://www.irv2.com/forums/attachmen...1&d=1576901943

Combination drip leg and external LP source for grill or whatever.

Externally heated propane generators, such as fork lifts, are a special case, and very sensitive to oils that tend to turn to sludge. Can't use commercial grade propane there.


Commercial grade propane is what we burn in the RV's, so it is not the cleanest available.




Phil

mgnorris 12-21-2019 11:50 AM

Quote:

Originally Posted by PSOUZA (Post 5082091)
The oil problems are variable, by region, and possibly by season. Caused largely by the shipping methods, after refining.


Reliable observations on actual amounts of oil recovered are scarce.


Drip legs don't seem to be common on RV's.


Externally heated propane generators, such as fork lifts, are a special case, and very sensitive to oils that tend to turn to sludge. Can't use commercial grade propane there.


Commercial grade propane is what we burn in the RV's, so it is not the cleanest available.




Phil

Spec HD5 propane. Itís the only LP that is used in northern tier states. You may see some other content in southern regions, more butane content. I have never heard of commercial grade, or any other grade of LP. It all comes through a pipeline to a terminal, then into either a truck tanker or rail tanker, to a dealer who delivers it to the end user, be it residential, commercial, or retail outlets in small prefilled tanks. Same gas in all applications. Been that way for at least 60 years with little change other than driver license requirements.

PSOUZA 12-21-2019 12:08 PM

Quote:

Originally Posted by mgnorris (Post 5082108)
Spec HD5 propane. It’s the only LP that is used in northern tier states. You may see some other content in southern regions, more butane content. I have never heard of commercial grade, or any other grade of LP. It all comes through a pipeline to a terminal, then into either a truck tanker or rail tanker, to a dealer who delivers it to the end user, be it residential, commercial, or retail outlets in small prefilled tanks. Same gas in all applications. Been that way for at least 60 years with little change other than driver license requirements.




Be nice if that were so.


https://www.propane101.com/propanegradesandquality.htm

There are other, lesser known flavors also such as medical and food grade, but not relevant here as they are special order.


Phil

grindstone01 12-21-2019 12:12 PM

It still does not make sense that oil is coming out of a propane tank. As many other post stated the oil would not turn into vapor at -34F to be able to get out through the valves.
If there were oil in a propane tank, the only way to get it out would be to empty the tank first then turn it upside down and open/remove the valve.
Pictured below is a full 20lb tank and the liquid propane should not make contact with the valve.

https://encrypted-tbn0.gstatic.com/i...Yni4B5rxMTazzd

AnotherMike 12-21-2019 12:56 PM

Quote trimmed for brevity...

Quote:

Originally Posted by mgnorris (Post 5081768)
Liquid propane boils at -34 f. It’s heavier than air, so it will lie on the ground, seep into cracks, and be there for longer than you realize.

I remember my dad telling a story about a car show he was taking photos of... he closed his photo studio in 1981, so this incident was probably in the mid 1970s... it was a parked-on-the-street auto show on a windless day, and one of the cars was propane-fueled and apparently had a slight leak in the propane system... my memory of him telling the story says Stanley Steamer... and the driver forgot to shut off the propane tank after parking the car...

The propane seeped along the ground, into the gutter, down the slope of the street, found a storm drain grate, and descended into the sewer system. Somehow it was ignited and the resulting explosion blew a half-dozen manhole covers into the air.

One manhole cover was slammed into the bottom of a pickup truck hard enough to tip the truck onto it's side.

There's a LOT of energy in a half-dozen gallons of LPG...

Mike

PSOUZA 12-21-2019 01:01 PM

Quote:

Originally Posted by grindstone01 (Post 5082138)
It still does not make sense that oil is coming out of a propane tank. As many other post stated the oil would not turn into vapor at -34F to be able to get out through the valves.
If there were oil in a propane tank, the only way to get it out would be to empty the tank first then turn it upside down and open/remove the valve.
Pictured below is a full 20lb tank and the liquid propane should not make contact with the valve.

https://encrypted-tbn0.gstatic.com/i...Yni4B5rxMTazzd



What you have read and heard is wrong. The oil, does indeed, become vapor if it is miscible.


Propane physics can be complicated, but here we go.


Propane is a solvent. It dissolves most oils . The oil molecules bind to the propane molecules in the empty spaces. The propane will dissolve oil until it is saturated. That is a lot of oil. Under normal conditions, there will not be any oil left in the bottom of the tank. More on those conditions later. Where the propane vapor goes, so goes the oil.


Think of gasoline and oil in a premix 2 stroke engine. How would you separate the oil from the gas?? You would evaporate the gasoline and the oil would remain. Or you could run the two stroker, where the gas would be vaporized by the carburetor and the oils would fall out of the vapor and condense in the crank case. Some would be burned immediately and the rest would be eventually be swept up and out by the turbulence and leave thru the exhaust. Some similarities to our propane model.


The propane will hold the oil in suspension indefinitely, or until it undergoes a state change. Until it evaporates into a gas. At that point, in the regulator, the oil will drop out of suspension and coat the surfaces of the regulator and hoses, coalesce and become a liquid.


The special conditions where oil may remain in the tank are:


1. The oil is not miscible (Can't be dissolved in propane). It got there from a severely contaminated source. You're screwed and must clean out the tank. The good thing is, that oil can't leave the tank and cause trouble. It can only reduce the amount of propane the tank can contain.



2. The oil dropped out of suspension because the propane was near saturation and the temperature dropped. Cold propane holds less oil than hot propane. The good news is that any miscible oil remaining in the tank, will be dissolved back into the propane when the temperature rises or when a fresh, clean load of propane is pumped into your tank.


Phil

grindstone01 12-21-2019 01:25 PM

Hi Phil - Thanks for the reply. Two issues I see is that gasoline in a engine situation does not go to a true gas state but becomes small droplets through the carb or injector system. Therefor the mixed oil also remains in a liquid droplet form.
The second issue is when propane liquid turns into a true gas, it should (engineer here, not a chemist) drop out the oil much like a osmosis system would to purify water. Only the propane gas would exit the tank valve drawn off from the top 20% of the tank. In other words, the propane liquid would never enter the regulator, only the propane gas at high pressure from the tank which is then reduced to a lower pressure in through the regulator.

PSOUZA 12-21-2019 02:01 PM

Quote:

Originally Posted by grindstone01 (Post 5082242)
Hi Phil - Thanks for the reply. Two issues I see is that gasoline in a engine situation does not go to a true gas state but becomes small droplets through the carb or injector system. Therefor the mixed oil also remains in a liquid droplet form.
The second issue is when propane liquid turns into a true gas, it should (engineer here, not a chemist) drop out the oil much like a osmosis system would to purify water. Only the propane gas would exit the tank valve drawn off from the top 20% of the tank. In other words, the propane liquid would never enter the regulator, only the propane gas at high pressure from the tank which is then reduced to a lower pressure in through the regulator.


Glad you brought this up as it reflects a bit on the previous post.


Propane is a bit of a rogue when it comes to the states of matter. We have all been conditioned to think of gas and vapor as the same state. In propane, and butane, this does not work. I can't cite all of it off the top of my head, but it has to do with state and equilibrium. Propane liquid and vapor can both exist at the same temperature and pressure at the same time.


Propane vapor is really both liquid and gas where the liquid has yet to fully change state.



The result is that the vapor contains the same miscible materials as the liquid, and in the same proportions.


Look at it another way. If the propane were to change state to a gas while still in the tank, the miscible materials would never leave it.


Must not confuse the visible white cloud of released propane to the air with the true vapor (in the tank). The true vapor is invisible.


This is hard information to get in a lay-man digestible form. Three years ago Google threatened me with terms of use because of the intensity of my searches :eek:


The conflict in the two stroke engine is a result of our conditioning in the sloppy use of the gas/vapor thing.

Another way to look at it. This is a still (short cracking tower) Where the progressively lighter fractions are drawn off.



Propane recovery of crude products in the ground where propane injected and pumped back to the surface where the propane is removed and the crude allowed to fall out.


OR in the food industry where butane and propane are used to extract oils that contain flavor compounds.


OR the illegal drug hash oil labs that use similar processes.


I think we may want to clarify our positions a bit more, but I have just been called away for bit. and the edit window is closing.


Phil

PSOUZA 12-21-2019 03:28 PM

Apologize if this becomes repetitious...too many balls in play...





Quote:

Originally Posted by grindstone01 (Post 5082242)
Hi Phil gasoline in a engine situation does not go to a true gas state but becomes small droplets through the carb or injector system. Therefor the mixed oil also remains in a liquid droplet form.


The second issue is when propane liquid turns into a true gas, it should (engineer here, not a chemist) drop out the oil much like a osmosis system would to purify water. Only the propane gas would exit the tank valve drawn off from the top 20% of the tank. In other words, the propane liquid would never enter the regulator, only the propane gas at high pressure from the tank which is then reduced to a lower pressure in through the regulator.




1. The gasoline is atomized by the carburetor into small liquid droplets, which in this case contain oil dissolved in the gasoline. The heat in the air helps to vaporize the fuel droplets, which turn into vapor. Without the liquid gasoline to carry it, the oil drops out. Remember liquid gasoline does not burn directly, it must be vaporized. The conventions we must observe do not let us use the term gas for gasoline that has vaporized, but in this case it is a distinction without a difference.



2. Indeed, the liquid propane should never touch the regulator (in an ideal world).
The propane vapor contains all the miscible materials, in the original proportions, as the liquid. It has not changed state yet, nor has the pressure dropped. Remember propane exists in stable form (equilibrium) in both vapor form and liquid form. Only when the pressure drops to near atmospheric, does the state change to gas. Then the oil drops.

This duality of simultaneous existence in two separate forms is the source of all the confusion and fantasy tales associated with the use of this fuel.



Another point to understand is the frost that forms on the regulator during hard usage and certain other conditions is not because liquid propane is entering the regulator. It is because the propane vapor from the tank is under the exact same pressure as the tank interior and has not yet began to expand to change to a gas. This expansion inside the regulator takes energy and that has to come from the outside air. The air dumps it's heat into the regulator to fuel the final expansion of the vapor into gas. The frost is the result.

busting a lot of bubbles today, :D



phil


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