You want to put the heat on the bottom so the chips can heat up. Spread the chips out on a baking tray, not to loose. You can soak the chips in water or fruit juice for half an hour. You can also use a wok to smoke your grains, probably easier if you have a small amount, you can control the...
Try filtering it first, so it doesnt keep fermenting in the keg. I have the same problem if I dont drink it for a while. Real big bubbles and alot of crap. I vent the keg and it is good to go in about 15 minutes