Bonnema on mon 6 mar 00
I want to add our experience with liquid propane firing to the discussion.
For several reasons, two of which were to get rid of the 1000 gallon above
ground tank in our backyard, and to extend the life of the burners we are
using that were designed to draw liquid propane, but which we have been
using for a year and a half drawing vapor, we decided to go to a 500 gallon
buried tank and have a liquid feed line installed. I was assured by the
owner of the company who supplies our propane that this would be the way to
go, power in reserve, and no worry about freeze-ups in these Maine winters.
He estimated that the cost would be 1 days work for two of his men, the
cost of the materials, and whatever the excavator cost. That was in early
October 1999. We still do not have a workable liquid system. Fortunately,
we have been able to fire on vapor by keeping the tank almost full before
starting any firing in the winter.
I am sure that using liquid draw is a great system, and it is possible that
we may be able to fix the problems that we are having, although we are
thinking that it may be best for us to just cut our losses and tell the
propane people that we don't want to mess with it any longer and we will
stick with the vapor system and keeping the tank full.
I suggest that anyone looking into switching to liquid propane do some
research. Find out how much experience your supplier has with liquid feed
systems. I found that what they said they knew and what they knew were
different. Ask what the local codes are for liquid feed. In Maine there are
much stricter regulations for liquid than vapor. The pipe is special black
iron pipe, the valves are special, and there are more of them, like back
check valves and excess flow valves. Things that I had no experience with
in 29 years of firing kilns with vapor. Also, the way that you fire your
kiln is important. We use a long slow firing with only half the pressure
that is recommended for the burners. That seems to make a big difference on
how they perform with liquid. We had such extreme surging when firing with
liquid that I couldn't control the reduction and had to switch back in the
middle of the firing to vapor. It seems to be important what the ambient
conditions are around the pipes and hoses that feed the burners. All things
that I should have researched better before we started the installation.
I would be very glad for any feedback.
Garret Bonnema
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Garret Bonnema
Bethel, Maine
bonnema@megalink.net
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