Physical Simulation of Bubble Behaviors and Optimization …
145
0
1
2
3
4
5
6
0
20
40
60
80
100
120
140
Number of bubbles
Diameter(mean)/mm
h=2cm
h=3cm
h=4cm
Fig. 14 Bubble size distribution under different height of agitator. (Color figure online)
Since the conversion of phosphogypsum to ammonium sulfate also involves a gas–
liquid two-phase reaction, the optimal conditions for gas–liquid mixing obtained by
water simulation exploration are suitable for the experiment of converting phosphogypsum to ammonium sulfate. Other fixed factors in the experiment are: liquid–solid
ratio of 1:10, nitrogen-sulfur ratio of 2.5:1, temperature of 55 °C, reaction time of
60 min, eccentric stirring is 0.4, the inlet gas flow is 0.12 m
3 /h, and the height of
agitator is 3 cm. The effect of three different agitators on the conversion rate of
phosphogypsum was studied under different stirring speeds.
It can be seen from Fig. 15 that no matter which agitator is selected, the conversion rate of phosphogypsum increases with the increase of the stirring speed. This
is because the stirring speed can increase the gas–liquid-solid three-phase mixing
during the reaction. Which improve the gas–liquid contact area and promote the
reaction. When the stirring speed is 600 r/min, the conversion rates of CBY, SSB,
and SSB-D agitator are 87.2%, 88.9%, and 91.95%, respectively. This is because the
circular plastic plate on the SSB-D agitator hinders the rise of gas, it improves the
uniform mixing effect of gas–liquid-solid three-phase, and accelerates the formation
of CaCO 3 and (NH 4 ) 2 SO 4 .
Conclusion
(1) The difference in the height of agitator has little effect of micro-bubble in the
reactor, which can be ignored in the experiment of converting phosphogypsum
to ammonium sulfate.
145
0
1
2
3
4
5
6
0
20
40
60
80
100
120
140
Number of bubbles
Diameter(mean)/mm
h=2cm
h=3cm
h=4cm
Fig. 14 Bubble size distribution under different height of agitator. (Color figure online)
Since the conversion of phosphogypsum to ammonium sulfate also involves a gas–
liquid two-phase reaction, the optimal conditions for gas–liquid mixing obtained by
water simulation exploration are suitable for the experiment of converting phosphogypsum to ammonium sulfate. Other fixed factors in the experiment are: liquid–solid
ratio of 1:10, nitrogen-sulfur ratio of 2.5:1, temperature of 55 °C, reaction time of
60 min, eccentric stirring is 0.4, the inlet gas flow is 0.12 m
3 /h, and the height of
agitator is 3 cm. The effect of three different agitators on the conversion rate of
phosphogypsum was studied under different stirring speeds.
It can be seen from Fig. 15 that no matter which agitator is selected, the conversion rate of phosphogypsum increases with the increase of the stirring speed. This
is because the stirring speed can increase the gas–liquid-solid three-phase mixing
during the reaction. Which improve the gas–liquid contact area and promote the
reaction. When the stirring speed is 600 r/min, the conversion rates of CBY, SSB,
and SSB-D agitator are 87.2%, 88.9%, and 91.95%, respectively. This is because the
circular plastic plate on the SSB-D agitator hinders the rise of gas, it improves the
uniform mixing effect of gas–liquid-solid three-phase, and accelerates the formation
of CaCO 3 and (NH 4 ) 2 SO 4 .
Conclusion
(1) The difference in the height of agitator has little effect of micro-bubble in the
reactor, which can be ignored in the experiment of converting phosphogypsum
to ammonium sulfate.