Have I got this wrong? I have read several times that when a natural
gas stove is converted to propane that it puts out less heat. Looking
in Machinery's Handbook it says that propane has more heat per volume
and a higher flame temperature. So how can the stoves burn cooler?
Thanks,
Eric

Eric R Snow wrote:

Have I got this wrong? I have read several times that when a natural
gas stove is converted to propane that it puts out less heat. Looking
in Machinery's Handbook it says that propane has more heat per volume
and a higher flame temperature. So how can the stoves burn cooler?
Thanks,
Eric

Well, you use less propane -- the orifice is MUCH smaller. But I always
thought a gas stove with 12kbtu burners had 12kbtu burners whether it
was hooked to NG or propane. Go figger.

Grant

SNIP

Well, you use less propane -- the orifice is MUCH smaller. But I always
thought a gas stove with 12kbtu burners had 12kbtu burners whether it
was hooked to NG or propane. Go figger.

Grant

Yes, Grant, the orfices are much smaller for CNG. I've been looking for
a long time to find out those sizes as I want to convert a nice little BBQ
to natural gas and nobody can give me a size for the new hole. I'd
think there's a formula or chart to use to go from a given size propane
orfice to go to natural gas....

can anybody help?

TIA.... bILL

In article JYuud.4297$ve.1261@fed1read06, "Bill P"
wrote:

SNIP

Well, you use less propane -- the orifice is MUCH smaller. But I always
thought a gas stove with 12kbtu burners had 12kbtu burners whether it
was hooked to NG or propane. Go figger.

Grant

Yes, Grant, the orfices are much smaller for CNG. I've been looking for
a long time to find out those sizes as I want to convert a nice little BBQ
to natural gas and nobody can give me a size for the new hole. I'd
think there's a formula or chart to use to go from a given size propane
orfice to go to natural gas....

can anybody help?

TIA.... bILL



Try going to your local stove repair shop and look at orfices for
propane and NG for the same stove. Bring your own drill set to measure
the holes and establish the ratio.

--
Free men own guns, slaves don't
www.geocities.com/CapitolHill/5357/

On Fri, 10 Dec 2004 21:46:40 -0700, "Bill P" wrote:

SNIP

Well, you use less propane -- the orifice is MUCH smaller. But I always
thought a gas stove with 12kbtu burners had 12kbtu burners whether it
was hooked to NG or propane. Go figger.

Grant

Yes, Grant, the orfices are much smaller for CNG. I've been looking for
a long time to find out those sizes as I want to convert a nice little BBQ
to natural gas and nobody can give me a size for the new hole. I'd
think there's a formula or chart to use to go from a given size propane
orfice to go to natural gas....

can anybody help?

TIA.... bILL

Just take out your set of #60 to #80 drills and start with the
smallest until the flame looks right. I did this for a camp stove that
was made to run on propane at the tank pressure. With a regulator
between the tank and stove the flame was quite small. Just going up
one drill at a time it took about 30 minutes to get the right flame.
ERS

On Fri, 10 Dec 2004 21:46:40 -0700, "Bill P" calmly
ranted:

SNIP

Well, you use less propane -- the orifice is MUCH smaller. But I always
thought a gas stove with 12kbtu burners had 12kbtu burners whether it
was hooked to NG or propane. Go figger.

Grant

Yes, Grant, the orfices are much smaller for CNG. I've been looking for
a long time to find out those sizes as I want to convert a nice little BBQ
to natural gas and nobody can give me a size for the new hole. I'd
think there's a formula or chart to use to go from a given size propane
orfice to go to natural gas....

can anybody help?

Call your local gas company or a conversion supplier and ask one of
their technicians. Or google for an answer:
http://www.google.com/search?num=100...ane+to+natural


================================================== ============
Like peace and quiet? Buy a phoneless cord.
http://www/diversify.com/stees.html Hilarious T-shirts online
================================================== ============

This is about the best packet of info for this type conversion I've seen
after a hours' cramming from the Google link. It relates back to other
sites and info as well as a link on how to make a simple water column
pressure guage. There is also a link to a chart to cross reference for
orifice sizes as compared to WC pressures. There is even reference to
multiple orifices and hybrid burners.
THIS is an EXCELLENT SITE.

http://www.komar.org/bbq/mm/convert/dannos.html


Thx again, guys!.... Bill

On Sat, 11 Dec 2004 07:23:09 -0800, Eric R Snow
wrote:

On Fri, 10 Dec 2004 21:46:40 -0700, "Bill P" wrote:

SNIP

Well, you use less propane -- the orifice is MUCH smaller. But I always
thought a gas stove with 12kbtu burners had 12kbtu burners whether it
was hooked to NG or propane. Go figger.

Grant

Yes, Grant, the orfices are much smaller for CNG. I've been looking for
a long time to find out those sizes as I want to convert a nice little BBQ
to natural gas and nobody can give me a size for the new hole. I'd
think there's a formula or chart to use to go from a given size propane
orfice to go to natural gas....

can anybody help?

TIA.... bILL

Just take out your set of #60 to #80 drills and start with the
smallest until the flame looks right. I did this for a camp stove that
was made to run on propane at the tank pressure. With a regulator
between the tank and stove the flame was quite small. Just going up
one drill at a time it took about 30 minutes to get the right flame.
ERS

I like this plan. Since the above question was how to go from propane
to NG, it should work well. Going the other way, it is easy to reach a
point where the amount of air you can get into the burner and mixed
with the gas limits how much you can increase the orifice size.

Pure methane (the major component of NG) has a stoichiometric air-gas
ratio of 9.53 to 1 on a volume basis (the weight ratio is 17.2 to 1).
For air-propane, you need 23.82 to 1 by volume, or 15.25 to 1 by
weight.
http://www.process-heating.com/CDA/ArticleInformation/Energy_Notes_Item/0,3271,84749,00.html

The BTU/cuft for NG is 1012, and for propane is 2516, so you need only
40% as much propane by volume for the same output. Taking 40% * 23.82
/ 9.53 gives almost exactly 1 - theoretically the same amount of air
through the burner, with 40% as much propane, should give the same
output.
http://www.altenergy.com/propaned.htm

Somehow in real life I've never found that to be true. NG is lighter
than air and mixes well with it, but propane is heavier than air and
doesn't want to flow up and out of the burner. Even though propane is
delivered at much higher pressure, it doesn't seem to encourage
airflow as well. The sizes of the holes where the mixture actually
emerges at the base of the flame are as critical as the orifice - too
small and the flame lifts off the burner and goes out; too large and
the flame pops back through the holes and burns at the orifice making
enough black soot to clog the burner.

Not only have I never reached equal heat output converting from NG to
propane, I've usually run into serious usability issues that forced me
to back off to even lower than maximum possible output.

Anybody out there understand why?

Loren

Somehow in real life I've never found that to be true. NG is lighter
than air and mixes well with it, but propane is heavier than air and
doesn't want to flow up and out of the burner.

Loren... Isn't NG a bit heavier than air (N+O2)? Why does it collect
in missle silos (sp) rather than float up and out when the doors and
vents are open?
Just wondering...
Bill

Yes, Grant, the orfices are much smaller for CNG. I've been looking for
a long time to find out those sizes as I want to convert a nice little BBQ
to natural gas and nobody can give me a size for the new hole. I'd
think there's a formula or chart to use to go from a given size propane
orfice to go to natural gas....



Bill
There appears to be too many variables to give you an answer.
From:
http://www.iccsafe.org/cs/codes/2004...es/FuelGas.pdf

"To select correct orifice size for rated burner
input. The selection of a fixed orifice size for any rated
burner input is affected by many variables, including orifice
coefficient, and it is recommended that the appliance
manufacturer be consulted for that purpose. Where the
correct orifice size cannot be readily determined, the orifice
flow rates, as stated in the tables in this appendix, can be
used to select a fixed orifice size with a flow rate to
approximately equal the required rated burner input."

But I think that there is enough information in that PDF file that you could
get pretty close by comparing your existing orifice size. There are 32 pages
of information and table for your perusal.

Hope this helps.

Lane

On Sat, 11 Dec 2004 13:35:42 -0800, Loren Amelang
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email


Pure methane (the major component of NG) has a stoichiometric air-gas
ratio of 9.53 to 1 on a volume basis (the weight ratio is 17.2 to 1).
For air-propane, you need 23.82 to 1 by volume, or 15.25 to 1 by
weight.
http://www.process-heating.com/CDA/ArticleInformation/Energy_Notes_Item/0,3271,84749,00.html

The BTU/cuft for NG is 1012, and for propane is 2516, so you need only
40% as much propane by volume for the same output. Taking 40% * 23.82
/ 9.53 gives almost exactly 1 - theoretically the same amount of air
through the burner, with 40% as much propane, should give the same
output.
http://www.altenergy.com/propaned.htm

makes sense, and it saved me the trouble....G

Not only have I never reached equal heat output converting from NG to
propane, I've usually run into serious usability issues that forced me
to back off to even lower than maximum possible output.

Anybody out there understand why?

I wonder if it's because propane is _not_ delivered at much higher
pressures. BBQs etc have that regulator that really throttles things
down. You get a propane heating torh that comes straight off the
bottle and it has no trouble with burnback or blowout, and really
belts out the heat. Also I have a propane-based instant gas water
system, and it roars with gas and produces enormous amounts of heat.
Again at a higher pressure, largely letting the orifice do the work.
---
Only worry about the things you can control.

Then you have stuff all to worry about!

One reason for the non match is Propane is very often Not Propane.

Liquefied Petroleum gas or LPG - is a mixture of a number of gases
to make a general heat content of real Propane.

In warm states Butane is the word and they switch to LPG / Propane
in the winter as it won't liquefy like Butane will.

My bet is the mixture.

Martin
Loren Amelang wrote:

snip

I like this plan. Since the above question was how to go from propane
to NG, it should work well. Going the other way, it is easy to reach a
point where the amount of air you can get into the burner and mixed
with the gas limits how much you can increase the orifice size.

Pure methane (the major component of NG) has a stoichiometric air-gas
ratio of 9.53 to 1 on a volume basis (the weight ratio is 17.2 to 1).
For air-propane, you need 23.82 to 1 by volume, or 15.25 to 1 by
weight.
http://www.process-heating.com/CDA/ArticleInformation/Energy_Notes_Item/0,3271,84749,00.html

The BTU/cuft for NG is 1012, and for propane is 2516, so you need only
40% as much propane by volume for the same output. Taking 40% * 23.82
/ 9.53 gives almost exactly 1 - theoretically the same amount of air
through the burner, with 40% as much propane, should give the same
output.
http://www.altenergy.com/propaned.htm

Somehow in real life I've never found that to be true. NG is lighter
than air and mixes well with it, but propane is heavier than air and
doesn't want to flow up and out of the burner. Even though propane is
delivered at much higher pressure, it doesn't seem to encourage
airflow as well. The sizes of the holes where the mixture actually
emerges at the base of the flame are as critical as the orifice - too
small and the flame lifts off the burner and goes out; too large and
the flame pops back through the holes and burns at the orifice making
enough black soot to clog the burner.

Not only have I never reached equal heat output converting from NG to
propane, I've usually run into serious usability issues that forced me
to back off to even lower than maximum possible output.

Anybody out there understand why?

Loren


--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

On Sat, 11 Dec 2004 17:37:59 -0700, "Bill P" wrote:

Somehow in real life I've never found that to be true. NG is lighter
than air and mixes well with it, but propane is heavier than air and
doesn't want to flow up and out of the burner.

Loren... Isn't NG a bit heavier than air (N+O2)? Why does it collect
in missle silos (sp) rather than float up and out when the doors and
vents are open?
Just wondering...
Bill

Well, I hadn't _really_ checked the exact numbers, so...
http://www.engineeringtoolbox.com/22_334.html

Air 1.000
Butane - C4H10 2.067
Ethane - C2H6 1.049
Ethylene (Ethene) - C2H4 0.975
Methane - CH4 0.554
Natural Gas (typical) 0.660

I think the answer to your question is similar to one of the comments
about propane - "natural gas" can include a lot of heavier components
along with the methane. For sure, the methane will rise out of the
silo, but just about any other flammable component will stay down.

Loren

On Sun, 12 Dec 2004 09:59:17 +0800, Old Nick
wrote:

On Sat, 11 Dec 2004 13:35:42 -0800, Loren Amelang
vaguely proposed a theory
....
- theoretically the same amount of air
through the burner, with 40% as much propane, should give the same
output.
http://www.altenergy.com/propaned.htm

makes sense, and it saved me the trouble....G

Not only have I never reached equal heat output converting from NG to
propane, I've usually run into serious usability issues that forced me
to back off to even lower than maximum possible output.

Anybody out there understand why?

I wonder if it's because propane is _not_ delivered at much higher
pressures. BBQs etc have that regulator that really throttles things
down. You get a propane heating torh that comes straight off the
bottle and it has no trouble with burnback or blowout, and really
belts out the heat. Also I have a propane-based instant gas water
system, and it roars with gas and produces enormous amounts of heat.
Again at a higher pressure, largely letting the orifice do the work.

Standard pressure around here for regulated and piped propane service
is 11" WC. The natural gas service I'm familiar with was between 4"
and 5" WC. Other parts of the world may be completely different...

With a burner designed for propane, it is no problem to get a roaring
fire. And you're right, they tend to make more noise than NG.

Loren

On Sun, 12 Dec 2004 04:47:13 GMT, "Martin H. Eastburn"
wrote:

One reason for the non match is Propane is very often Not Propane.

Liquefied Petroleum gas or LPG - is a mixture of a number of gases
to make a general heat content of real Propane.

In warm states Butane is the word and they switch to LPG / Propane
in the winter as it won't liquefy like Butane will.

My bet is the mixture.

Now that you mention it, I have noticed the usability of my converted
gas range changing with the seasons. At my home here in California it
rarely gets too cold even for pure butane, but I guess my gas company
delivers on the other side of the mountain with the same trucks, so
they proably are changing mixtures.

Loren

"Loren Amelang" wrote in message
...
On Sat, 11 Dec 2004 17:37:59 -0700, "Bill P" wrote:

Somehow in real life I've never found that to be true. NG is lighter
than air and mixes well with it, but propane is heavier than air and
doesn't want to flow up and out of the burner.

Loren... Isn't NG a bit heavier than air (N+O2)? Why does it collect
in missle silos (sp) rather than float up and out when the doors and
vents are open?
Just wondering...
Bill

Well, I hadn't _really_ checked the exact numbers, so...
http://www.engineeringtoolbox.com/22_334.html

Air 1.000
Butane - C4H10 2.067
Ethane - C2H6 1.049
Ethylene (Ethene) - C2H4 0.975
Methane - CH4 0.554
Natural Gas (typical) 0.660

I think the answer to your question is similar to one of the comments
about propane - "natural gas" can include a lot of heavier components
along with the methane. For sure, the methane will rise out of the
silo, but just about any other flammable component will stay down.

Loren

Appreciate the info! I guess for the sake of limited paper space in
the article I read some time ago, the author was either ignorant him
self or had to cut down on article size hence making the statement
'methane gas collected in copious quantities missle silos and detection
devices were mandatory....'

thx again Loren!!

Bill

Loren Amelang wrote:

On Sun, 12 Dec 2004 04:47:13 GMT, "Martin H. Eastburn"
wrote:


One reason for the non match is Propane is very often Not Propane.

Liquefied Petroleum gas or LPG - is a mixture of a number of gases
to make a general heat content of real Propane.

In warm states Butane is the word and they switch to LPG / Propane
in the winter as it won't liquefy like Butane will.

My bet is the mixture.


Now that you mention it, I have noticed the usability of my converted
gas range changing with the seasons. At my home here in California it
rarely gets too cold even for pure butane, but I guess my gas company
delivers on the other side of the mountain with the same trucks, so
they proably are changing mixtures.

Loren
I first got wind of it in Texas - Dallas area - winter gas and summer gas.
The company name changed from xxxx Propane to xxxx LPG and that started the
questions. Someone called them on the Summer gas that was weaker than
the winter gas - non house use.

Martin [ bought his first 20 gallon tank there and now have a 30 for furnace ]

--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

On Sun, 12 Dec 2004 18:07:26 -0800, Loren Amelang
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

Standard pressure around here for regulated and piped propane service
is 11" WC. The natural gas service I'm familiar with was between 4"
and 5" WC. Other parts of the world may be completely different...

OK. But I have a torch that runs straight off the gas tank, no
regulator. I can't see why BBQ burners cannot be allowed to run LPG at
a pressure that allows them to be as good as NG.


With a burner designed for propane, it is no problem to get a roaring
fire. And you're right, they tend to make more noise than NG.

hmmm....I wonder if the burner design is the problem, and that's why
LPG will either suck back or blow otself out. I was really supposing
(am still) from limited experience. I look at the "ring" and "strip"
burners that run from the tank via a regfulator and they are every
slow.
---
Only worry about the things you can control.

Then you have stuff all to worry about!