Can 2 9v batteries heat an electric range heating element
That is a 240V (or thereabouts) 2100W element, meaning it draws about 8.75A. You could conceivably use 65 or 70 16850 batteries in series, which would weigh about 3.5kg for the batteries alone. Some batteries allow discharge current in that range. Many do not allow it safely. 

If you get 70% of, say, 2.5Ah then it might run for 10 or 15 minutes, enough to boil your tea and prepare some dehydrated food if it doesn't explode and take whatever structure it's in plus your face with it. 

240VDC with so much current and charge capacity is also potentially lethal, more so even than 240VAC out of the wall. 



As far as PP3 9V batteries, it would take quite a few of them in series-parallel to run that for any length of time and again, would be dangerous for shock at a minimum.