purging lines when converting from lp to natural?

[RoBoTeq]

I have heard in the past that many gases may be introduced to natural gas systems during peak demand to maintain supply.

I don't doubt it. Any of the "anes" would boost natural gas. But LP is so abundant, being a byproduct of oil production. Also, BGE (Baltimore Gas & Electric) actually has large LP storage tanks and caves. Ironically, BGE has been the major promoter that LP gas is some sort of dangerous monster in its quests over the years to expand it's service areas.

[MicahWes]

I seriously doubt LPG is ever stored in caves (unless it is in a steel vessel). Natural gas is very often stored in caves and other underground structures (and sometimes in pressurized vessels at low temperatures), but LPG is always stored as a liquid under pressure.

[RoBoTeq]

I seriously doubt LPG is ever stored in caves (unless it is in a steel vessel). Natural gas is very often stored in caves and other underground structures (and sometimes in pressurized vessels at low temperatures), but LPG is always stored as a liquid under pressure.

Doubt it all you want, but it's true. LP is heavier than air, so caves are a perfect place to store it. In Cub Hill, MD, BGE has a cave storage facility that has been there for decades. I can't find it online, but I've been to the facility enough times in my youth, and the sign on the security fence clearly states that there are caves being used for LP storage for BGE.

[MicahWes]

If LPG stored there, it must be in pressurized vessels in liquid form?

[RoBoTeq]

If LPG stored there, it must be in pressurized vessels in liquid form?

From what I have been led to believe, the LP is simply pumped into the caves and pumped out when needed. As long as a cavern has all entrances and exits controlled, it makes a perfect, temperature stable storage area for the heavier than air LP gas. For safety, LP stored in caves would be pressurized and liquified after removing it from cavern storage facilities. At least that is what I have been told by BGE personnel who claim to have worked at the Cub Hill facility.

[RoBoTeq]

Here's something to read about LPG storage caves;

Liquefied Petroleum Gas (LPG), is a compressed by-product of petroleum
distillation. While Iowa is not a producer of petroleum or natural gas, it does
store large volumes of liquefied butane, propane, and ethane in excavated
"caverns" deep beneath the land surface. LPG products arrive in Iowa via
pipeline from Wyoming, Utah, and Canada and are injected into these underground
facilities, which provide safety, economy, and operating flexibility.

The storage caverns were excavated from shale or shaly limestone into rooms
about 20 ft wide and 20 ft high with 45 ft-wide pillars left for support. Two
LPG storage caverns are located in southeast Johnson County at depths of 490 ft
and 770 ft. They both began operation in the 1960's. In Polk County, three
storage caverns were excavated at depths of 375 ft, 595 ft, and 1,410 ft beneath
a single tract of land at the southeast edge of Des Moines. These became
operational between 1967 and 1970.

http://www.igsb.uiowa.edu/Browse/storegas/storegas.htm

[just robert]

Just a follow up to bring my saga to a conclusion.
The gas utility company tied into the building and I converted all the units from propane back to natural(they were ordered 5 years as nat. gas and were converted to propane at that time in anticipation of nat. gas coming one day).
Everything went well.
Upon startup a few of the hot air furnaces clearly had a "hotter" flame for a second or two but other than that no discernible issues were noted.
It's been about a month now and the first set of gas bills are starting to trickle in,with noticeably lower costs vs.propane.
The tenants are happy!
Thanks again for everyone's help!
Bob

[RoBoTeq]

Just a follow up to bring my saga to a conclusion.
The gas utility company tied into the building and I converted all the units from propane back to natural(they were ordered 5 years as nat. gas and were converted to propane at that time in anticipation of nat. gas coming one day).
Everything went well.
Upon startup a few of the hot air furnaces clearly had a "hotter" flame for a second or two but other than that no discernible issues were noted.
It's been about a month now and the first set of gas bills are starting to trickle in,with noticeably lower costs vs.propane.
The tenants are happy!
Thanks again for everyone's help!
Bob

Always good to know when things work out.

[koolkahuna]

The worse that would happen is the burners would burn a little hot for a minute or so until the LP gas is burned off. Up to 20% of LP is mixed with natural gas during really cold weather in some areas.

You've got class Robo. No "I told you so".
WDGAFS.

[OldSchoolMech]

I wanna see proof that propane is mixed with Natural gas to bump up demand. I have never heard or read this and I am in a cold climate with NG

I got a new idea NG furnace propane kit gives it a shot of propane on those colder days extra BTU when you need em like a NOS kit for your car.

[RoBoTeq]

You've got class Robo. No "I told you so".
WDGAFS.

Hell, I just forgot what we were originally discussing....

Thanks for taking notice..