Effect of rotor speed on CO2 capture

https://doi.org/10.1016/j.ijggc.2013.12.005

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Fig. 4, Fig. 5 show effects of varying rotor speed on CO₂ capture level for 56 wt% and 75 wt% lean MEA concentrations at 20.9 °C and 39.5 °C lean MEA temperatures. The results show that CO₂ capture level increases with increase in rotor speed for both 20.9 °C and 39.5 °C lean MEA temperatures due to enhanced mass transfer. Rotation of the absorber enhances mass transfer by stimulating combined droplet and film flow (Burns et al., 2000). This behaviour increases with rotor speed. Also, at higher rotor speed the problem of liquid mal-distribution is overcome leading to higher wetted area which subsequently contributes to improving mass transfer.

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Fig. 4. Effect of rotor speed on CO₂ capture level at 56 wt% MEA.

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Fig. 5. Effect of rotor speed on CO₂ capture level at 75 wt% MEA.

Fig. 4, Fig. 5 also show that CO₂ capture levels at different rotor speed are affected by the lean MEA temperatures. At 20.9 °C lean MEA temperature, CO₂ capture level increases more significantly with increase in rotor speed than at 39.5 °C lean MEA temperature even though actual capture level is higher at 39.5 °C lean MEA temperature. The capture level at 39.5 °C lean MEA temperature is close to 100% and as such increasing rotor speed has less effect on it. Again, comparing Fig. 4, Fig. 5 for 20.9 °C lean MEA temperatures in Fig. 4 the capture level increases from 81.61% to 84.93% as rotor speed increases, but in Fig. 5, capture level increase from 83.06% to 90.40% which is more significant than in Fig. 4. The reason for this behaviour is that CO₂ capture level is higher at 75 wt% MEA concentration than at 56 wt% MEA concentration since reaction rate is a function of concentration.

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