Yes mate that should do the trick providing it has a decent flame control.
On most of these you will find that the flame is rather wide so the applied heat is a tad spread.
The idea is to only heat the nut up so that it expands on the bolt so a commercial oxy/accy gun is always best but a regular blow torch should be up to the task.
Remember that you will also require a 14mm, 19mm and grips to stop the knuckle from turning when loosening the seized outer nuts.
Also please remember and take the necessary fire prevention precautions.
Good luck
Cheers,
Alex.