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Gas–liquid mass-transfer behaviors in aqueous alcohol solutions were studied in an internal-loop airlift reactor of 5-m height and 0.28-m i.d. in the superficial gas velocity (U g) range from 2.0 to 10.0 cm/s. Air and aqueous n-butanol solutions were used as the gas and liquid phases, respectively. It was found that the volumetric mass-transfer coefficient decreased with increasing n-butanol concentration (C A) below a critical C A value of 0.5 wt % and increased with increasing C A above this concentration. To confirm this result, further experiments were also carried out in a bubble column of 0.12-m i.d. at U g = 6 cm/s, and similar results were obtained. Further analysis showed that the value of k l a/αg was independent of the superficial gas velocity and equal to 0.21 1/s in the air–water system; however, it decreased with increasing C A up to 0.25 wt % in n-butanol solutions, and further addition of n-butanol had no effect on k l a/αg. A critical C A value of 0.5 wt % was also found for the liquid-side mass-transfer coefficient (k l). Below this concentration, k l decreased with increasing C A, whereas above this concentration, further addition of n-butanol had no effect on k l.

SO42− anchors to a NiMo/γ-Al2O3 catalyst, weakening the metal–support interactions, inhibiting MoS2 aggregation, increasing the number of Ni–Mo–S sites, and thus improving its activity and stability.

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