Oxygen Enrichment for Combustion of Producer Gas

The latter.

The latter as #1↑, but also consider that as you add oxygen to a combustion air stream and reduce the overall mass of air required for stoichiometric combustion the actual combustion temperatures will begin to increase proportionately due to the lower absorption mass. This may be negligible though, even including the actual % of air required over stoichiometry for complete combustion.

Why you are doing Oxygen Enrichment?

You missed the main REASON WHY!

Your Initial designer wanted Augmenting the Flame temperature- to get increased Radiant heating.

Good that you practiced first and questioning NOW

I have not implemented it. I am just making sure of all the things goes in the right direction. This is only the start. Depending upon the percentile of Oxygen the whole system has to be revamped and then comes the inoculation.

Enhanced Flames are good for Billet reheating

But all things need be under Control!

There is one more element which has to be considered, i.e. the rate of oxidation of the billets. As, any extra loss of steel to oxidation would be counter productive. What do you say?

There is always some "scale" of oxidized metal on the surface of re-heated, or re-melted metal. I do not suppose that there will be a noticeable increase in the oxidation of the billets. I do suppose you will reach the intended temperature target somewhat faster, so in fact, could there be less oxidation?

Also, none of the metal is lost to you. It remains present as an oxide that can be sent back into the beginning of the process.

The huge extra Radiation power brought in by the O2 Augmented flame-- and Re -radiation from Refractory roof hastens the heating of the billets to rolling Temp.

This is the net aim: minimum transit time through the Furnace .

Scale is already there. Any extra Scale buildup is effect of time in/through furnace .

It is going to be Productive -Not Counter Productive .

At 0% air excess - Producer gas flame Temp=1780C

At 40% air excess - Producer gas flame Temp= 1400C

With O2 augmentation and less than Stoichiometric air - Temp could go to 1850+

And increased Radiation Energy to Billets from H2O,CO2 AND refractory goes up at 4th powers!

Would you please share with us the equation (Planck equation?) for blackbody radiant energy as a function of temperature? I seem to have misplaced this in the back corner of my brain.

ALL IN:

http://en.wikipedia.org/wiki/Black-body_radiation#cite_note-Rybicki_1979_22-27

AND THIS IS A GOOD SUMMARY :

http://www1.eere.energy.gov/manufacturing/tech_deployment/pdfs/oxygen_enriched_combustion_process_htgts3.pdf

Of course, as you say the flame temperature would go up considerably, however, I feel Thermal Conductivity of the steel determines the rate at which the heat transfer is taking place, irrespective of the temperature of the flame. Therefore, number of billets in the furnace could be increased but cannot change the rate of heat transfer. Am I right?

No- that rate is proportionate, therefore as the ΔT goes up so does the actual rate of transfer in unit value. Therefore, you could be better with a hotter flame (allowing shorter residence time) whereas increasing the BTU value of your existing system would simply allow you to put more billets in.

Could you please elaborate it.

You need revisiting First year Science at Junior College:

Conduction,Convection,Radiation!!

Mukul,

I am a Mechanical Engineer, specialized in manufacturing of Machines and Machine Tools for the past 35 years!!!. I have just strayed into Thermal Engineering quite recently. Not that I do not know anything about Thermal Engineering but it makes difference in time. As you said, its regarding Radiation Conduction and Covection. It is more than that. It is the activation energy required to kick off the reaction. Since you are a GURU, I need not explain to you

You strayed on to the right Track-keep to Thermal -Energy Saving-Basic Engineering --Excellence.

Machine design and Building is fun no more.

CNC has ousted you and me .

Happy Heat transferring!

Thank you Mukul, looking forward for help from you and from the Senior members of the forum to keep myself on the track.

Got it JNB. no need to explain

Dear Mukul,

I have downloaded PHAST Version 3.0 recently. I find on the oxygen enrichment ,it says that the flue gas temperature should be more than the combustion air temperature. I am not able to understand. Can you help? Please try it ,if you have the software.

Govind Rao

If not so - how will there be a draft ?

Hot "air" is Lighter than cold -- will have to go up the chimney.

If I am not wrong, the flue gas temperature has to kept somewhere in the region of 200 degrees Celsius. The combustion air picks up heat from the recuperator ( Heat Exchanger) in the region of 500 degrees Celsius before it is fed into to the reheating furnace for combustion.

200 degC is the norm

See these -- Good material

http://www1.eere.energy.gov/manufacturing/resources/steel/pdfs/thermochemical_recuperation.pd

www.undpgefsteel.gov.in/LinkClick.aspx?fileticket...tabid=234