Propane Tanks IF you have pulled one, Ups, Downs r just good Advice? Thanks

If you look close at a transport trailer you will see at the botton of the tank you have your internal valve, and right after that it bolts to the 4" blackmer pump. Then if you look at the path the LIQUID takes, it flows thru a short pipe and then you have your liquid line. So the liquid propane essentially gravity feeds thru the bottom internal valve into the pump and then thru your hose to your recieving tank. Another words liquid propane does get pumped thru the pump. Just saying, ive been doing it for years.

 

You used the same set up as me Pcpirate. I hauled LPG for 6 years on the gulf coast everyone had the blacker pump used to pump liquid, then suddenly Lonestar NGL shows up with a different setup using a compressor instead of a pump. It drew vapor from the tank and pressurized the trailer with it forcing liquid to move toward the tank. This whole argument between these two gents was entertaining for me because I knew they in fact were both right. Well, except for the gent who called the compressor on his truck a pump, that's inaccurate and creates confusion.
About the relief valves on top of the trailer, mine was set at 250 and 265. When it reached 250 you would hear the valve seeping gas but when it hit 265, it sounded like an explosion and looks like a gyser, the vapor blowing out so rapidly it actually liquifies blowing out then vaporizes again before hitting the ground. Let me also add that I can't imagine why steam would be used to unload propane. It would mix with the propane and contaminate it. I've seen plant use compressors to unload us, natural gas, and even nitrogen but using steam is hard for me to believe.

 

What does a compressor do? I was relating to the guy asking the question with my experience with the equipment that I used and how it works. I have never pumped liquid propane through a pump. I also said that I thought the smaller trucks did. Now I do have a question about how you deliver all the product possible ( vapor is product or turns into product when it cools) and the customers we went to would lose their minds if we left without pumping out vapor pressure down in our tanks.

And yes,, I had a top relief valve fail one morning as I was getting loaded.. sounded like a bomb going off! kind of ruins your day.. and the companies day... The relief valves kind of look like an industrial strength pogo stick..

 

The vapor stays with the trailer. It was their before you loaded and is there after you unload. The only time we pulled pressure was when we needed to load butane. We would unload raw mix and have 200 psi on the trailer when finished. We would weigh out pull under rack and hook up a vapor recovery hose and pull pressure down to 60 psi. Then we would weigh back in to load butane. Doing that we would loose roughly 800# of product. But if we were just hauling propane then the trailer always stayed at the normal vp depending on temp.
The blackmer pumps we use can only move liquid. Trying to push vapor with it simply will overheat the pump and if not caught soon enough, will overheat the pump causing the grease in the pump bearings to run out of the weep holes, melt the sliding vanes in the pump, and possibly cause a shaft seal failure.

Im curious how you pull pressure into customers tank without over pressuring their tank and setting off their relief valves in the heat of summer?

 

Hmm.. that's strange. We used to haul butane also and there really was no vapor pressure involved.. it was light and like hauling water. We would sometimes haul butane to propane tanks to lower the vapor pressure. Not sure the customers would ever know really. But we did unload butane into propane tanks

It was a pain in the rear at took forever to unload. Your pressure and their pressure were roughly the same and HIGH! over 200 PSI.. so you'd still have to pull pressure off your tanks until the product started moving and there were times were you could here the relief valves rattling... a bit unnerving to say the least.. most of the time there though it was pointless to try and pump the vapor down to 60 on your tank as it would take forever and be a colossal waste of time as when the outside air temp was 110+.. its not like the tank would cool much.

 

Some facilities required no more than 50psi to load butane because their pumps couldn't buck the pressure. And some required at least 50psi to load propane or it would set off the check valve. I know all about those check valves rattling, on location in Alabama would check once your pressures equalized and vapor started returning to the truck. I went there enough to learn u only open the ball valve on the vapor line 3/4 of a turn on a valve that took about 3 full turns to open. It would slowly pressure up the tank and would usually check when u were down to about 30%. Then I'd upen the other tank and finish the load off in it. Otherwise I would have to stop pumping and wait for presume to equalize.

 

I am thinking about hauling propane. Any companies around Atlanta hiring owner ops

 

The only one I can think of is maybe Abston Transport, now out of Petal, Ms. Used to they were in Gilbertown, AL but recently moved. Not sure if they operate in that area but I know they have a few trucks that pull out of Opelika, AL and the Carolina's.

 

Check PTI. Propane transporters I believe. They hire O/o's seasonally. Hauling propane is easy in wintertime due to the pressure issues minimized. It's easy and straight forward.