Firing a Reidhammer Furnace with tar.

[op9]

I have been asked to look into the possibility of firing tar (heated to reduce its viscosity) in place of natural gas under the refractory hood of a Reidhammer furnace.

A Reidhammer furnace is used for baking carbon anodes to be used for subsequent aluminium production using electrolysis. The main source of heat is through many natural gas injection points into a high temp air flow which moves through the checker brickwork and up and under the refractory lined hood. The temperature is maintained >950deg C, well above the auto ignition temp of natural gas.

The tar is a byproduct (waste) of the furnace and the intention is to dispose of it through one burner(or injection point) which will fire under only one hood, replacing 5 gas inlets.

I realise that any fuel will burn as long as it is reduced in viscosity sufficiently, then atomised, and ignited, but I was wondering if anyone had specific experience on this type of furnace.

Thanks in advance,
Rod. [sig]<p>Rod Nissen<br><a href=mailto:nissenr@one.net.au>nissenr@one.net.au</a><br><a href= > </a><br> [/sig]

 

[easternequipment]

We have done some work on such furnaces earlier. Please advise the following :

1. Do you need to dry graphite electrodes ?
2. What is the type of burner you are using ?
It seems you now add natural gas at various stages in the flue / products of combustion stream. Where does it get the combustion air.

3. We have a lot of experience burning tar and tar like fuels which are predominantly used in India even for Billet Re-heating furances and aluminium melting.

4. You can use a single combustion chamber at one end to generate hot products of combustion / flue gases using tar like fuels. In your kind of furnaces, flue recirculation and recuperation of waste heat should also be seen. Preheated combustion air particularly useful when burning Low C.V. and Difficult to Burn fuels like Heated Tar in Liquid form.

Hope this was of assistance.

best regards,

VIKAS AGRAWAL.
easternequipment@vsnl.com

 

[jmw]

With heavy fuel oils, bunker C and other viscous fuels they are atomised by the burner nozzle. Viscosity is an important factor in optimising the atomisation process i.e. getting the right droplet size and dispersion. Usually the fuel is heated to a temperature which should ensure the viscosity is within the design limits for the nozzle. Depending on what this temperature typically is (and it will vary due to variation in tar quality) you can now use viscosity measurement to control the tar heaters. Try ViscoMaster at solartron.com