Set point for injecting coal tar in blast furnace

[bmsg]

I am an instrumentation engineer.
We are doing the engineering for injection of coal tar into tuyeres of a big blast furnace. This is slated to bring down the coke rate in the furnace.
We know that about 30 to 50 kg of coal tar per tonne of hot metal is the norm.
But, the set-point for tar injection (in terms of flowrate) must vary with the blast-furnace parameters, somehow.
Or, should it to be at a constant rate?
Will anyone tell me what or suggest a link / reading material?

 

[dbuzz]

You might try your query at the Metal and Metallurgy engineering Forum.

 

[drgauf]

Can you elaborate on the material percentages?

 

[drgauf]

Remember that aluminum expands faster than SS under the same excitation

 

[drgauf]

Isuggest you refer to the "coke and smelters, a journeymans adventure", raed it, know it, then attempt to ask this again...

 

[tc002]

Please refer to AIST.org. This is the iron and steel technology association. Or contact the AISE the professional society for steel engineers. Coal tar addition has to be regulated specifically to the operating parameters of the BF, by the way.

 

[heieup]

We inject granular coal into our BFs (not coal tar ?) at about 200 kg/thm.

It varies based upon the current BF operation (stable or not and output rates desired, higher injection at higher output rates)

 

[tc002]

The conventional BF has operated using iron ore, limestone and coke for eons. Over the last decade or so there has been an attempt to replace the reducing fuel (coke), put into the top of the furnace, with a replacement fuel put into the tureyes, granulated coal, tar, coal fines, or any other fuel, most, I think have been tried, somewhere. The source depends on availability of what is laying around as cheap waste in most cases. Some add natural gas or propane or some other hydrocarbon. Since there is a requirement for specific amounts of a carbon or hydrocarbon to reduce the oxides in the iron the coke value is replaced by the addition of these fuels into the tureyes. A specific calcullation is made not only on the heating values but as well the carbon or hydrogen value, as added. Therefore the rate will vary depending on the throughput and types. This rate will also vary if the iron ore is changed or that rate. There is also an amount that must be provided as extra due to the requirement to keep the gaseous content reducing rather than oxidizing.