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Removal of SO2 using ammonium bicarbonate aqueous solution as absorbent in a bubble column reactor
Received date: 21 Jan 2013
Accepted date: 25 Mar 2013
Published date: 05 Jun 2013
Copyright
In this work, the removal of SO2 from gas mixture with air and SO2 by ammonium bicarbonate aqueous solution as absorbent was investigated experimentally in a bubble column reactor. The effects of the concentration of ammonium bicarbonate, the SO2 inlet concentration of gas phase and the gas flow rate on the removal rate of SO2 were studied. The results showed that the higher the SO2 inlet concentration and the gas flow rate, the shorter the lasting time of SO2 completely removed in gas outlet, and then the faster the decrease in the removal rate of SO2. The lasting time of SO2 completely removed in gas outlet increased with increasing ammonium bicarbonate concentration. During the process of SO2 absorption, there was a critical pH of solution. When the solution pH was less than the critical pH, it would sharply fall, resulting in a rapid decrease of the SO2 removal rate. A theoretical model for predicting the SO2 removal rate has been developed by taking the chemical enhancement and the sulfite concentration in the liquid phase into account simultaneously.
Key words: SO2 removal; bubble column reactor; removal rate; ammonium bicarbonate; absorbent
Xiaolei LI , Chunying ZHU , Youguang MA . Removal of SO2 using ammonium bicarbonate aqueous solution as absorbent in a bubble column reactor[J]. Frontiers of Chemical Science and Engineering, 2013 , 7(2) : 185 -191 . DOI: 10.1007/s11705-013-1326-5
a | Specific interfacial area per unit volume, m2·m-3 |
A | Liquid-phase concentration of A, mol·m-3 |
Ai | i = 1, 2, 3, 4, 5, 6 parameters in Eq. (16) |
Ar | Debye-Hückel parameters in Eq. (15) |
Br | Debye-Hückel parameters in Eq. (15) |
CAL | Concentration of the component A in the liquid bulk, mol·L-1 |
CAG | Concentration of the component A in the gas phase, mg·m-3 |
db | Average gas bubble diameter, m |
d0 | Orifice diameter, m |
dR | Bubble column reactor diameter, m |
D | Diffusion coefficient, m2·s-1 |
E | Eenhancement factor |
G | Gravitational constant, m·s-2 |
H | Henry’s law coefficient |
Ha | Hatta number |
I | Ionic strength, kmol·m–3 |
ki | i = 1, 2, 3, 4, 5, 6 reaction rate constant |
kG | Gas side mass transfer coefficient, m·s-1 |
kL | Liquid side mass transfer coefficient, m·s-1 |
kmn | Reaction rate constant in Eq. (28) |
Ki | i = 1, 2, 3, 4, 5, 6 equilibrium constant |
KL | Total mass transfer coefficient of SO2, m·s-1 |
KC | Total mass transfer coefficient of CO2, m·s-1 |
Q | Volume flow rate of gas, L·min-1 |
Re0 | The orifice Reynolds number |
ub | Bubble rise velocity, m·s-1 |
ϵG | Gas hold-up |
μG | Viscosity of gas phase, kg·m-1·s-1 |
μL | Viscosity of liquid phase, kg·m-1·s-1 |
ρG | Gas density, kg·m-3 |
ρL | Liquid density, kg·m-3 |
σL | Surface tension of liquid, N·m-1 |
Activity coefficient |
C | Carbon dioxide |
G | Gas phase |
L | Liquid phase |
S | Sulfur dioxide |
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