2 replies to this topic

[renato.dick]

First post here...

I need to estimate the mass flow of exhaust gases and the particulate material concentration in this stream for a biomass boiler (sugarcane bagasse).

I think i have all the data needed like the composition of the biomass, the usual %excess air rate, boiler thermal efficiency but i dont know the route to estimate the total gases and the particulate material.

Need this info to especify a scrubber for this gas and later a water treatment station for the resulting waste water.

Hope u guys can help.
TY

[PingPong]

You need to know the exact composition of the biomass, including its water content, to calculate the flue gas it will yield.

Water will obviously appear as H2O vapor in the flue gas.

C atoms from biomass will appear as CO2 in the flue gas,

H atoms from biomass will appears as H2O in the flue gas,

S atoms from biomass will appear as SO2 in the flue gas,

N atoms from biomass will appear as N2 in the flue gas,

Based on that you calculate required O2 from air,

N2 from air will obviously appear as N2 in flue gas.

 

How much particulates will appear in the flue gas depends on the whole design of the biomass boiler. Biomass also contains ash. Does the boiler remove part of that ash? Otherwise all ash will be carried into the flue gas.

Is there soot produced in the boiler? If so you can not calculate that but need typical operating data from similar boilers.

[renato.dick]

Thank you very much for your answer.

 

I did the math to estimate the flue gas flow with your tips and worked perfectly.

 

Now, about the particulate content i´m still working on it.

 

I did a lot of research about this and have a lot of info to share that might help.

 

I found in some literatures, values from 8.000 mg/Nm³ to 10.000 mg/Nm³, but i don´t know how accurate is that and there were no major details about it so... i´m still needing help in this case.

 

Adicional informations:

 

Boiler type of my case: Two cases: 1-Monodrum Fixed grate type and 2-Monodrum Bubbling fluidized bed;

Ash content: is being removed in the grate openings and carried with water, or for case 2, being mixed with the sand in the bed (i´m assuming that none of the ash is going to be carried by the gas);

Soot: I´m assuming that for case one, 1-3% of the fuel will be carried by the flue gas as soot, and for case 2 - 0,5%;