6 replies to this topic

[Criss]

I am treating a gas (from coal combustion) which contains SO2, and I want to absorb this SO2 in order to reduce the emission value.
Up to now I have chosen NaOH as absorbent, but I am having some problems: gas temperature is too high (500ºC) for the absorption, so I need to reduce this temperature, but I cannot find any scientific document that can justify the reduced value for the temperature.

I want to ask for information about the optimum temperature for inlet gas.
If anyone has worked in something similar I would really appreciate any kind of recommendation

Thank you very much in advance

[Art Montemayor]

Criss:

I did this a lot a long time ago. I don't have the time right now to draw a schematic to show you, but perhaps you could do the job in order to specifically attack the problem. I scrubbed out the SO₂ from flue gas at 500 ^oF - not ^oC. But the Unit Operation is basically the same.

You can do what you propose with a packed tower. You don't give us any basic data, so I can't be specific. In order to give an engineering opinion, we need the usual, normal basic data: flows, temperatures, pressures, compositions, etc., etc.

You should circulate a caustic solution around the packed tower, quenching the hot flue gas stream, and absorbing the SO₂ - all in the tower. You recirculate the caustic through a heat exchange device where you remove the heat picked up in the tower. The process is a batch one that lasts for the duration of the caustic in the solution. You have to makeup the water vaporized in the quenching section.

I'll be back when you produce some basic data so we all can deal in specifics, and not just generalize.

[Criss]

The inlet gas is approx 400ºC, it is composed by: N2, O2, CO2, CO, SO2, HCl, NO2 and H2O
I am treating it with a liquid with NaOH and H2O.
I am in doubts, because I have been reading articles related to this topic, but I cannot find the reactions taken part in the absorption. (I want to know what components are formed to absorb SO2)(I have been reading an article which says that there are several reactions along the scrubber, and finally the components in the outlet liquid are H2O, NaHSO3, H22SO3 and SO2, but I thought that Na2SO3 was formed)

On the other hand, speaking about the temperature for the absorption, I have found that 50ºC is used in most of the articles I have read.

This is the information I need, right now, to start with the simulation.
If you need further information, please let me know.

Thank you very much

This is classically used technolgy in almost all NAPHTHA /GAS CRACKER PLANTS AS WELL AS CAN BE USED IN COAL-FIRED POWER PLANTS AND COAL-BASED STEEL PLANTS.

YOU MAY EVEN USE LIME SLURRY AS WELL. CAUSTIC SOLUTION THAT YOU ARE USING MUST BE OF ABOUT 10% STRENGTH.

THE END PRODUCT OF IT AFTER SCRUBING THRU THE NAOH 10% COLUMN MUST BE IN A COUNTER CURRENT FLOW. THE CLASSICAL TEMperature MUST BE BROUGHT DOWN TO ABOUT 150-200 DEG C. BEFORE THE GAS ENTERING THE NAOH COLUMN,

THE PRODCUTS THAT ARE FORMED IN THE OUTLET OF THE NAOH SOLUTION ARE Na₂SO₃, Na₂S,phenolic compounds from the inlet gas,and some oliy products like green oil.

should you require full length consultancy we can provide you on professional scale.

Thanks,

Kaushikk

[prateek1991]

hello criss

i am working on the same project now... and i have been asked to treat a flue gas whos composition has been provided to me... now what i have studied and have been told is that i shouldnt use a packed bed scrubber because due to the salt formation pores in the bed would get blocked.
so i am supposed to use a spray chamber scrubber rather than a packed bed.. could u help me in any way? i need a basic layout of the process... like what all would be the components in the entire process and how they would be arranged...

[Shivshankar]

Hi,


The topic can be found in below book

CONTROL OF POLLUTANTS IN FLUE GASES AND FUEL GASES
by Ron Zevenhoven & Pia Kilpinen

http://users.abo.fi/...ho/SulphOH1.PDF
http://users.abo.fi/...ho/SulphOH2.PDF

Regards
Shivshankar

[prateek1991]

hi shivshankar...

m glad that u r tryng to help me.. but i couldnt find what i was asking in the link that u have posted..
the above link describes the process for sulphur dioxide treatment using lime/limestone. it just has brief things aboutcaustic scrubbber technique... i would need more detailed data than this... if you could help me than it would be great...

thanks
prateek