Hello,

I would like to get in contact with people simulating pulverised coal combustion using Fluent v5.

I am currently simulating a full-scale PC boiler, and I would like to discuss solution procedures, submodels, parameter values etc. with experts in the area.

Sincerely, Anders Jungar Åbo Akademi University, Finland

Hi,

This is Esther Hontanon, from CIEMAT (public research center in Madrid,Spain). Actually, I belong to the Fossil Fuel Department. We've simulated combustion in a coal-fired power station 550 MW (it's a full-scale swirling flow type furnace) with FLUENT 5.4. If you are interested in it I can send you by e_mail a poster on that we presented at the First Meeting of the Spanish FLUENT Users held in Barcelona on October 6th, 2000.

Best Regards. Esther

Dear Anders Jungar

How can I say "I am an expert" ? However, I have several experience for PC combustion by Fluent 4.x and 5.x. If you need any information, do not hesitate contact me.

Sincerely, Jinwook

Dear Jin-Wook LEE and Dr Esther Hontanon,

Before I go to my questions, I shall briefly explain the case I'm currently running. It's a 250 MW coal-fired, Benson type (once through) boiler operating in Lahti, Finland. The boiler is equipped with 12 swirling burners (low_NOx) and has the following dimensions 12 (depth), 7 (width) and 50 (height). All units in meters.

I would like to know what submodel you have been using for surface char combustion? Diffusion, kinetics/duffusion limited or the intrinsic? Or possibly a UDF? If so , have you used Fluent's default parameter settings for the models?

My two(2) major problems are as follows:

1.

Char burnout is in my case modeled using a Kinetic/Diffusion Surface Reaction Rate Model, i.e. char combustion rate is determined either by kinetics or by the diffusion of O2, using Fluent's default parameters for the model. The oxygen and temperature profiles (both should be largely affected by char burnout, shouldn't they?) do -not- fit together with the char burnout profile, i.e. despite char burnout, no major changes in O2 and temperature can be observed. Char burnout occurs close to the burners, after all volatiles have emerged. That's OK. But what is striking is that I get a char burnout in the upper part of the boiler also, i.e. I have burnout in two completely different regions.

2.

What under-relaxation factors (URF) have you been using? I started the calculations by patching a temperature of 1600 K on the whole flow field and using URF of 0.2 for turbulence and viscosity, and 0.5 for all others (energy, density etc.). Slowly I have -decreased- the others from 0.5 to 0.3. The strange thing is that every time a Discrete Phase iteration takes place (I have to use a coupled iteration procedure, of course), the residuals jump up, so the residuals get a so called "saw-teeth" alike profile. I would also be interested to hear what parameter settings you have been using for the Discrete Phase when modeling coal combustion.

Sincerely, Anders Jungar Åbo Akademi University, Finland

[bharath]

Dear Dr. Esther Hontanon,
am doing a 660MW furnace simulation.for that am doing single burner simulation to get BC profile in CFX12.but am having some convergence difficulties.i don't know how to setup the simulation in fluent.could you send some presentation or the materials you have to my mail id bharath102015@yahoo.co.in.

[chandrasekhar.gullapalli]

Can u guide me how to model furnace for 300MWe. I have boiler dimensions...

Now I would like to model it in fluent... Can u please guide me briefly... How to start?

[Nikolopoulos]

1. About the first issue, I don't believe that your problem is the model used for char burnout, but your boundary conditions. Perhaps your oxygen flux in the boiler is too small.
Try checking the flow rates through fluent -> Report -> fluxes.

What is your λ (stoichiometric ratio)?

As far as char combustion is concerned latter you can check the model of Hurt (variable order of reaction). We have tried that one with good results. However you will need a UDF.

2. This "Saw - teeth" is expected. No problem. To test your convergence calculate the overall energy balance of the plant. For a 300 MW plant it should be less than 300KW. About URF and solution procedure strictly follow Fluent's respective tutorial.


Keep up the good work in Åbo Akademi,

Nikolopoulos Aristeidis
CERTH/ISFTA

[bharath]

Hi chandrasekhar.gullapalli,
Sorry for the delay.have you finished your project?tell me more

[chandrasekhar.gullapalli]

Hi Esther Hontanon,

can you please forward the poster that you presented regarding pulverised fuel combustion in boilers. I am interested to see it...

mail id: chandrasekhar.gullapalli@gmail.com

Regards,

chandrasekhar G.

[chandrasekhar.gullapalli]

No Bharat,

Not yet started... Would like to see the gas simulation and steam simulation inside fluids simultaneously... Is it possible to do so, both at same time...

[bharath]

sorry i don't understand what you are telling? are you trying to model coal combustion first.

[anawana]

Originally Posted by Dr. Esther Hontanon
;95293

Hi,

This is Esther Hontanon, from CIEMAT (public research center in Madrid,Spain). Actually, I belong to the Fossil Fuel Department. We've simulated combustion in a coal-fired power station 550 MW (it's a full-scale swirling flow type furnace) with FLUENT 5.4. If you are interested in it I can send you by e_mail a poster on that we presented at the First Meeting of the Spanish FLUENT Users held in Barcelona on October 6th, 2000.

Best Regards. Esther

I am very interested in your research field, in fact my master project is Coal Gasification simulation, which is very similar to your object.Could you please send me your research paper presented at the first meeting ?My email:chenlongwhhit1989@gmail.com