@Grace of Thule I do something similar, which is fridge full of canola and shelf for chemfuel right next to the refinery

So, I have a small tip for you to solve the issue that you may be having. Create a shelf next to the biofuel refinery, which you fill with corn. Set the chemfuel production to 'drop at feet' in the bill menu, and the colonist will just create endless amounts of chemfuel quite rapidly. Your haulers will then take the chemfuel back to the stockpile at the end of the day.