Yes it is as long as it is a bottom tap king keg, or you could just get a pressure barrel as its cheaper than a king keg, take the existing tap out it is a 3/4 thread and rig your own fitting up with an isolation valve. I put my beer in different sized pressure barrels so I don't have to drink 40 pints in a couple of days, got hold of some 10 pints ones which I have yet to fill, 2gallon/ 20 pint ones are available from the-home-brew-shop.co.uk