Study on the Effective Mass Transfer Area and the Local Gas-Side Mass Transfer Coefficient in a Rotor–Stator Reactor

Abstract

To increase the applicability of a rotor−stator reactor (RSR) in gas−liquid mass transfer processes, the effective mass transfer area (a e ) and the local gas-side mass transfer coefficient (k G ) in the RSR were measured by employing a NaOH solution to absorb CO 2 and SO 2 , where gas radial velocity is required to be large enough to ignore the gas-side mass transfer resistance in determination of a e . The effects of operating conditions and stator rings on these mass transfer parameters were investigated. The experimental results showed that a e and k G in the RSR with stator rings were higher than those in the RSR without stator rings by 17−30 and 1−9%, respectively. a e in the RSR with stator rings was 3.4% lower than that in a rotating packed bed, but k G in such RSR was higher than that in the rotating packed bed by 78.6%, suggesting that the RSR has great potential for industrial applications in the processes controlled by gas-side mass transfer.

Selective Absorption of HCl from a Gas Mixture with CO2 by Alkali Solution in a Rotor–Stator Reactor

“…First, the high solubility of HCl in the aqueous solution, resulting in a low value of Henry’s constant ( H ) in eq , mitigates the sensitivity of K G to E HCl ( E of HCl is calculated by eq ), and thus the impact of c OH‑ on HCl absorption is diminished. Second, the high-gravity device demonstrates a significantly high liquid-side mass-transfer coefficient, which further attenuates the influence of c OH‑ on the HCl absorption process in the RSR. , E HCl = 1 + D OH − c OH − , normalL D HCl c HCl , normali …”

“…In this study, an RSR consisting of five layers of rotor rings and four layers of stator rings was employed, and the comprehensive specifications of the RSR configuration can be referred to in our previous works. , Comparison experiments were conducted by using a PC with Φ5 × 5 Dixon rings as packing. The specifications of the RSR and PC are shown in Table .…”

“…Second, the high-gravity device demonstrates a significantly high liquid-side masstransfer coefficient, which further attenuates the influence of c OH-on the HCl absorption process in the RSR. 13,20 = + A HCl mass-transfer model in our previous study 3 (which has been shown to describe HCl absorption in the RSR) was employed to investigate the effect of enhancement factors on K G at different k L . The calculation reveals that at the current operating condition in the RSR, k G is determined to be 3.7 mmol/(kPa m 2 s), and k L is 7.9 × 10 −4 m/s.…”

“…The RSR exhibits several advantages: (1) With its distinctive rotor and stator internals, the RSR demonstrates an outstanding selfcleaning effect; (2) the RSR features a straightforward structure and ease of operation, leading to reduced operating costs; (3) RSR has better gas-side mass-transfer performance and micromixing efficiency than RPB; (4) in comparison to traditional devices, the RSR offers the benefit of a compact size, contributing to a reduction in equipment investment. 11,20,21 Therefore, the RSRs have been applied to CO 2 absorption, nanomaterial preparation, and so forth. 11,22 This study presents an approach for the selective absorption of HCl using RSR to address the issue of excessive alkali consumption by CO 2 during the treatment of off-gas containing HCl and CO 2 in conventional columns.…”

“…The rotor–stator reactor (RSR) is an innovative high-gravity device, primarily composed of concentric rotor-rings and stator-rings arranged alternately in the radial direction. The RSR exhibits several advantages: (1) With its distinctive rotor and stator internals, the RSR demonstrates an outstanding self-cleaning effect; (2) the RSR features a straightforward structure and ease of operation, leading to reduced operating costs; (3) RSR has better gas-side mass-transfer performance and micromixing efficiency than RPB; (4) in comparison to traditional devices, the RSR offers the benefit of a compact size, contributing to a reduction in equipment investment. ,, Therefore, the RSRs have been applied to CO 2 absorption, nanomaterial preparation, and so forth. , …”