Not sure of the actual connection points on the kettle, but you could pump a heat transfer fluid through the jacket which is heated electrically. Oils or glycol could be used to circulate through the jacket and heat. Dowfrost is good to 250* and the HD is good to 325* so boiling with those is a possibility.
Looking at the cut sheet the relief valve could be removed and a tee added to allow the relief to remain just in case and an outlet point for the fluid at the top of the jacket. and the "condensate out" port used to pump into the jacket.
Starting 18 gallons strike water at 50* with 2 5500W heaters you could get to 170* in 30 minutes and 140* to a boil in 18 minutes IF you have no heat losses, so it seems reasonable.
You could deep fry the wings in the oil and make beer at the same time!!!
Electric Hot Oil Tank - eHOT