Search

Absorption of carbon dioxide into sodium hydroxide solution has been extensively used for mass transfer investigation in gas–liquid contacting reactors. To obtain a reliable value of effective mass transfer area (A), the selection of fundamental parameters, such as reaction rate constant, diffusion coefficient, and solubility data, is significant for data processing, and very little literature has been reported on the selection of these parameters. Therefore, an evaluation of the sources of fundamental parameters needs to be given. In this work, six parameter sources, including classic literature and newly published papers, were evaluated for effective mass transfer area measurement in a rotating packed bed. Quantitative comparisons demonstrated that using different reaction kinetics models will cause a large deviation in the values of the effective mass transfer area. Further, the inconsistency between the sources of kinetics models and physical properties can also cause a large deviation, which should b...

Coal still has a vital role in power generation, and coal-fired power plants are considered to be a main source of CO2 emission. This work proposed a process intensification (PI) technology, combining the highly efficient diethylenetriamine (DETA) solvent for CO2 absorption and the PI device of rotating packed bed (RPB) for enhancing gas-liquid mass transfer, to improve CO2 capture performance. Experimental study was conducted in a lab-scale RPB, and the dependences of CO2 removal performance on various operation conditions were systematically investigated. It was founded that CO2 loading has a vital effect on removal efficiency, and increasing rotation speed and solvent flow rate is beneficial to CO2 removal. The comparison of mass transfer performance between RPB and packed column (PC) demonstrated that the gas retention time in RPB with a value of 1.5 s is far shorter than that in PC under the similar operation conditions, which means RPB possesses a great advantage of shrinking mass-transfer device’s size for the CO2 capture process. Additionally, a Back-Propagation Neural Network (BPNN) model was developed for predicting the value of overall volumetric mass-transfer coefficient (KGav), and the predicted values agree well with experimental data with a satisfactory average absolute relative derivation (AARD) of 7.85%. These results demonstrated that this PI technology is expected to be a competitive candidate for improving CO2 capture performance from flue gas.

A novel rotating packed bed (RPB) reactor is first adopted to intensify the reaction of isobutane alkylation with 2-butene catalyzed by H2SO4. This work investigated reaction performance, and reaction conditions were optimized. Under the optimal conditions, the research octane number (RON) reached 98.85. Meanwhile, the yields of C8 and trimethylpentanes were 90.65% and 85.47%, respectively. The reaction efficiency was tremendously improved by using RPB due to its high efficiencies of mass transfer and micromixing. More importantly, the inner mole ratio of isobutane to 2-butene was dramatically decreased in RPB, which means the energy cost of material cycling in the alkylation process could be extremely reduced. Moreover, an empirical correlation model was proposed to predict the multiproduct yields and RON with a deviation within ±10%. In conclusion, RPB reactor is a highly promising industrial platform for the process of H2SO4 alkylation.

This study employed a rotating packed bed (RPB) to enhance the absorption performance of nitrogen oxides (NOx) into sodium hydroxide (NaOH) solution with the preoxidation of NO by ozone. The absorption performance of NOx was evaluated in terms of its removal efficiency (η) from a gas stream under various operating conditions including O3/NOx molar ratio (MR), rotation speed of the RPB (N), liquid flow rate (L), NaOH concentration (CNaOH), inlet NOx concentration (CNOx), and using time (t). Also, the corresponding effect of adding oxidants (NaClO, H2O2, and KMnO4) and a reductant (CO(NH2)2) into the NaOH solution on NOx removal efficiency was investigated. Results indicated that preoxidation of NO by O3 significantly improved NOx removal efficiency and the removal efficiency increased with increasing O3/NOx molar ratio, NaOH concentration, and liquid flow rate but decreased with increase in inlet NOx concentration and using time. Additionally, NOx removal efficiency first increased and then decreased with ...

The shortage of low-sulfur coking coal will bring about an increasingly high hydrogen sulfide (H2S) in the coke oven gas (COG) in the near future. This work investigated the removal of hydrogen sulfide (H2S) from a simulated coke oven gas (COG) by catalytic oxidative absorption in a rotating packed bed (RPB). Sodium carbonate (Na2CO3) solution doped with 20 mg L−1 of a commercial “888” catalyst was used as the absorbent. The removal efficiency of H2S was evaluated under various operating conditions including rotation speed of the RPB (N), liquid-gas ratio (L/G), inlet H2S concentration ( c H 2 S,in ), temperature (T) and Na2CO3 concentration ( c Na 2 CO 3 ) in an attempt to optimize the conditions. The results were validated by comparison with those of separate experiments conducted in a packed column comprising a high-efficiency laboratory packing of Dixon rings. The comparison results reveal that the RPB exhibited higher H2S removal efficiency than the packed column, indicating it as an efficient gas-liquid contactor with a greater potential to remove H2S from COG.

This study investigated the absorption performance of CO2 into a diethylenetriamine (DETA)-based solution containing piperazine (PZ) or 1-(2-aminoethyl)piperazine (AEPZ) as an activator in a packed column with Dixon rings. The effects of various operation conditions such as the activator concentration, gas flow rate, liquid flow rate, CO2 partial pressure, and solution temperature on overall gas-phase volumetric mass-transfer coefficient (KGav) were explored. Results indicate that the presence of PZ in DETA solution yields a better enhancement effect on KGav than AEPZ, and, thus, a combination of 5%PZ+25%DETA solution is expected to be a promising absorbent for CO2 absorption. The results further show that KGav increases with an increase in the liquid flow rate and a decrease in CO2 partial pressure and first increases and then decreases with an increase in solution temperature. On the other hand, the gas flow rate has an insignificant effect on KGav. A simplified empirical correlation for KGav as a funct...

This article presents systematic investigations on the mass-transfer characteristics, including the overall gas-phase volumetric mass-transfer coefficient (KGa) and the height of mass-transfer unit (HTU), of the CO2 absorption process into a mixture of diethylenetriamine (DETA) and piperazine (PZ) solution in a rotating packed bed (RPB). The effects of operating conditions, including PZ concentration, rotation speed, liquid volumetric flow rate, gas volumetric flow rate, gas treatment capacity of packing, inlet CO2 mole fraction, temperature, CO2 loading of lean solution, and distributor specification on KGa and HTU in the RPB, were systematically studied. Also, a comparison of CO2 absorption performance between the packed column with Dixon rings packing and the RPB is presented. Results indicate that both KGa and HTU were significantly affected by rotation speed, liquid volumetric flow rate, gas volumetric flow rate, temperature, and lean CO2 loading while the PZ concentration, inlet CO2 mole fraction, a...