and Kiln Firing
Natural Gas vs L.P. GasNatural gas kilns will easily
reach stoneware temperatures
Theoretical flame temperatures between these gasses are actually similar
but this is not the important point in this case. The heating value
of the gasses are different however, allowing more heat to be liberated
per volume of L.P. gas than natural gas. L.P. Gas has a heating value
of 95.5 MJ/m3 (2500 BTU/ft3) and natural gas liberates approx. 38
MJ/m3 (1000 BTU/ft3). All this really means is that we must ensure
that the burners, valves and the gas piping for natural gas firing
are sized to allow sufficient volume of gas to heat the kiln efficiently.
Luckily the costs of the gas are based on the heating value and not
the volume consumed. Although it depends on local pricing, generally
it is possible to obtain natural gas for about half the cost of bottled
Converting L.P. Gas Burners
To successfully modify existing L.P. Gas burners to operate on natural
gas, the gas pressure would need to be about the same. Usually the
town gas supply is reticulated at low pressure and it is therefore
not possible to convert the burners. Natural gas burners have larger
valves and burner parts to enable sufficient heat to be liberated.
If the gas pressures are the same, a simple jet size change should
Matching Natural Gas Burners To Your Kiln
Generally for a given kiln volume we would use more natural gas
burners than L.P. Gas burners to obtain the required heat input.
This can repay the owner with more even firings. Smaller kilns have
successful firings with a single burner provided a large preheat
pilot is fitted to assist with a low, steaming rate.
Advantages Of Natural Gas To L.P. Gas
Disadvantages Of Natural Gas To L.P. Gas
- Natural gas is "on tap". Consequently there are no worries about
empty or freezing gas cylinders or gas leaks during changeover.
- Natural gas is lighter than air and if a leak occurs the escaping
gas will rise, is rapidly diluted with air and easily dispersed.
In contrast L.P. Gas is heavier than air and tends to sink to
ground level, will accumulate and may cause an explosion. It is
important to treat all gasses with utmost caution.
- The burners are essentially large bunsen type units and if the
gas pressure is low are virtually noiseless in operation. Although
the venturi L.P. Gas burners are renowned as much quieter burners
than others, there is a noticeable difference with natural gas
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