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SO2 removal from gases

SO2 removal from gases

SO2 removal from gases

(OP)
We are working in the design of a lead recycling plant in uruguay (from scrap batteries).
To design the gas treatment operations, we are facing some difficulties regarding SO2 removal.
As using NaOH is proving too expensive, we have been offered a dry sistem, by injection of lime (CaO? Ca(OH)2?) to the gases, and then remove them in cyclone or filter (which would be there anyway).
How do we calculate lime consumption?
To what extent should we consider CO2 and CO competing?
What is the particulate size of products of reaction (CaSO4? etc)?
Can anyone send some process description?
Thanks,
Pablo

RE: SO2 removal from gases

Very common to use dry Ca(OH)2 upstream of a baghouse for SO2 removal.  Gas temp should be as low as possible (325F?)without causing corrosion and material handling problems with ash.

Expect to use a lot of lime - suggest NSR= 4-6 to get 75% reduction.

RE: SO2 removal from gases

Sulphuric acid production from SO2 laden flue gases is a matter of economics: investment, cost of plant operation, concentration of SOx in the flues, and, of course, possibility of marketing the acid.

pabasolo's idea of using a dry throwaway system seems right. Although it has fewer corrosion problems, less scaling difficulties and it appears to be easier in handling and disposal of the waste product, combination wet-dry, or wet lime systems are also in use. Either CaO or limestone (mainly CaCO3) could be used. NaCO3H or Na2CO3 are more effective but more expensive.

9741411 is absolutely right in saying you need much more CaO than stoichiometrically estimated. This is due, in particular, to the fact that gas-solid reactions are not so efficient and depend on the surface area of contact between both reacting phases. The size of the collected particles also depend on the size of the ground neutralizer used.

CO or CO2 do not compete much at the prevailing conditions with lime or limestone; they would, however, with NaOH wet systems, because of the higher pH.

Particle collection devices are often shake-deflate parallel bag houses, or of pulse-jet design, but can also be ESP.

Con augurios de exito.

ESP: Electrostatic precipitators.

RE: SO2 removal from gases

(OP)
Thanks to all
You have been extremely helpful!
bye

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