10 November 2008
Has anyone got any experience of using oxygen and/or acetylene
generators for use on an offshore drilling rig?
Are there any specific regulations that apply to the use of these
The reason for this is to minimise the use of gas bottles, and the
associated hazards with transportation and storage on the rig.
In remote or poor quality supply areas, the use of oxygen/acetylene
generators would have many benefits.
Mixing calcium carbide with water and compressing the acetylene gas
may sound simple, yet the associated; cooling, drying, filtering,
compressing, etc...apparrently is not. Given the relatively small
amounts we use offshore vs the space constraints we've tended to opt
As alternatives, colleagues recommend:
1) a plasma-arc cutter (available to cut steel to at least 4"
thick). Training requirements are minimal and apparently it operates
like a normal oxy-acetylene cutter except there's no continual
flame. The only consumable is electricity.
2) Propylene gas for cutting. The primary reason that you can get
much bigger bottles, and they last nearly twice as long as acetylene
so less bottle handling and fewer logistical problems. Propylene is
fine for cutting although it takes a little longer to get the cut
heated up. Once you do it actually cuts faster. Many cutters prefer
it because it is cleaner than acetylene so you don´t have to clean
the tips as much...You need new hoses, regulators and tips to make
No direct experience, however...
Acetylene is widely scorned by production facilities, particularly
UKCS. Reason given is primarly safety related due to the wide
combustion range, LEL-HEL, of acetylene. Oxy-propane is the usual
alternative found on these installations. My understanding (not
guaranteed) is welders don't like oxy-propane because is the mix
needs to be finely tuned to get the peroframce needed (probably
because propane is much more stable with a narrower combustion
range !). If acetylene storage is the issue, perhaps propane
(bottled or piped) might help.
Nigel D. Bradley
Senior Drilling Engineer