I have a 300 gallon waste motor oil tote on the side of the shop. I'm always thinking about a waste oil furnace although the Fisher stove works very well. It would be a nice secondary heat source if I leased the entire 40x60 building and not just half. A friend in the oil business came by and asked if I could use this set up, well sure I'll give it a go. I can't sleep sometimes with all ideas rolling around in my gray matter.
Dad used to heat his shop with a furnace that was designed to use straight drain oil...and we did, right out of the drain pan sometimes. Worked great! I wonder what ever happened to that thing?
Yes this oil will need to be filtered, the pump would transfer it to another container higher up in the shop for gravity filtering.
Here's a guy on another forum that converts oil furnaces to burn waste motor oil This requires filtered oil and better yet if its gone through a centrifuge. A costly turn key commercial waste oil furnace would only need minimal filtering but cost $5K plus. I really want a centrifuge because I like to clean stuff.