A prospective customer of mine has a used oil recycling plant. Part of the initial process is to heat the collected oil to about 105deg C and boil off mainly the water. Obviously light oil fractions are simultaneously released. He has a system to condense most of the released water vapour but there is an odour problem with the remainig gases vented to atmosphere. Others have suggested ducting these gases into the intakes of his steam generator burner combustion air fan. I am not keen on this as apart from the tricky situation of ignitable volatiles in the air stream these off gases will over a period of time cause unwanted deposits probably ignitable on the fan and air passages.

I realise a separate furnace and burner dedicated to fume incineration is a clear cut solution, but as he has no additional heating requirements the heat would be lost. My idea is to construct a plenum chamber around the existing generator burner and supply this from an extraction fan with the fumes so that they are introduced into the flame itself. Obviously we need to keep flow velocities high and install flame arrestors in the supply ductwork. I am only considering concepts at this stage because I have not been to site yet or know the volume flows and oxygen content of the fume stream etc, relative to the burner capacity.

By the way the burner fuel is waste oil and they are quite small, being only about 125KW on each steam generator. The present flue temps are quite high, around 280deg C so as long as they are kept high, dew point deposition/ corrosion should not be a problem.

Would appreciate knowing of anyones experience with a similar application.

Rod

Rod Nissen.
Combustion & Engineering Diagnostics
nissenr@iprimus.com.au
http://www.canded.com.au