Guangwen Chu

Process Intensification of VOC Removal from High Viscous Media by Rotating Packed Bed

Abstract The removal of a volatile organic compound (VOC) from high viscous liquid was carried out in a rotating packed bed (RPB) in this study. The mixed liquid of syrup and acetone was used as simulated high viscous polymer solution with acetone as the volatile compound. The influence of the rotating speed of RPB, liquid viscosity, liquid flow rate, vacuum degree, and initial acetone content in the liquid on acetone removal efficiency was investigated. The experimental results indicated that the removal efficiency increased with increasing rotating speed and initial acetone content in the viscous liquid and decreased with increasing liquid viscosity and flow rate. It was also observed that acetone removal efficiency increased with an increasing vacuum degree and reached 58% at a vacuum degree of 0.1 MPa. By the comparison with a flash tank devolatilizer, it was found that acetone removal efficiency in RPB increased by about 67%.

Micromixing Efficiency of Viscous Media in Micro-channel Reactor

Micromixing efficiency of viscous media in Y-type micro-channel reactor was studied by using iodide-iodate test reaction as working system. Experiments were carried out in water-glycerin mixtures with 7 different viscosities. The experimental results showed that segregation index of the micro-channel reactor increases with the decrease of volumetric flow rate and the increase of solution viscosity. Based on the incorporation model, the micromixing time tm of the micro-channel reactor was estimated in the range of 10^(-4)-10^(-3)s at different viscosities, which indicated that the micro-channel reactor possesses a much better micromixing performance compared to the stirred tank(t(subscript m)=0.02-0.2s).

Synthesis of Petroleum Sulfonate Surfactant by Different Sulfonating Agent with Application of HIGEE Technology

With the application of HIGEE process intensification technology, petroleum sulfonate surfactant used for enhanced oil recovery was synthesized from petroleum fraction of Shengli crude oil with three sulfonating agents, including diluted liquid sulfur trioxide, diluted gaseous sulfur trioxide and fuming sulfuric acid. For each sulfonating agent, different operation modes (liquid-liquid or gas-liquid reaction with semi-continuous or continuous operation) were applied. The effects of various experimental conditions, such as solvent/oil mass ratio, sulfonating agent/oil mass ratio, gas/liquid ratio, gas concentration, reaction temperature, rotating speed, circulation ratio, reaction time and aging time, on the content of active matter and unsulfonated oil were investigated. Under relatively optimal reaction conditions, the target product was prepared with high mass content of active matter (up to 45.3%) and extremely low oil/water interfacial tension (4.5×10−3 mN·m−1). The product quality and process efficiency are higher compared with traditional sulfonation technology.

Modeling of the Precipitation Process in a Rotating Packed Bed and Its Experimental Validation

Abstract A mixing-precipitation model based on the modified coalescence-redispersion model was presented to describe the flow, mixing, nucleation and growth in a rotating packed bed (RPB). The model was coupled with population balance, mass balance and crystallization kinetics. It predicted well the influence of coalescence probability, which represents the mixing intensity among droplets, on the particle number density, supersaturation and mean particle size of the produced precipitates. The effects of the radial thickness of packing, liquid flow rate and rotating speed on the product particle size were also investigated. The results indicate that the needed radial length of packing is short for sparingly soluble substance precipitation (about 40-50 mm in this work), and the mean particle size of precipitates decreases with the increase of rotating speed and liquid flow rate, respectively. The validity of this model was verified by experiment on BaSO4 precipitation in RPB.

A Mass Transfer Model for Devolatilization of Highly Viscous Media in Rotating Packed Bed

Abstract A mass transfer model for devolatilization process of highly viscous media in rotating packed bed (RPB) was developed based on penetration theory and mass conservation. Before establishing the model, some mass transfer experiments of thin film were conducted in a designed diffusion cell including vacuum and feeding system. In this study, acetone was used as the volatile organic compound (VOC) and syrup as the highly viscous media. The thickness of thin film was changed by using different liquid distributor. It was found that bubbling played an important role in the devolatilization. The correlation of diffusion coefficient of acetone in highly viscous dilute solution was proposed. The relative error between predicted and experimental data was within the range of ±30% for diffusion coefficient of acetone in syrup. A comparison of experimental data of RPB with model indicated that the relative error was within ±30% for efficiency of acetone removal.

Effects of Assistant Solvents and Mixing Intensity on the Bromination Process of Butyl Rubber

Abstract A slow bromination process of butyl rubber (IIR) suffers from low efficiency and low selectivity (S) of target-product. To obtain suitable approach to intensify the process, effects of assistant solvents and mixing intensity on the bromination process were systemically studied in this paper. The reaction process was found constantly accelerated with the increasing dosage and polarity of assistant solvent. Hexane with 30% (by volume) dichloromethane was found as the suitable solvent component, where the stable conversion of 1,4-isoprene transferring to target product ( x A1s ) of 80.2% and the corresponding S of 91.2% were obtained in 5 min. The accelerated reaction process was demonstrated being remarkably affected by mixing intensity until the optimal stirring rate of 1100 r·min −1 in a stirred tank reactor. With better mixing condition, a further intensification of the process was achieved in a rotating packed bed (RPB) reactor, where x A1s of 82.6% and S of 91.9% were obtained in 2 min. The usage of the suitable solvent component and RPB has potential application in the industrial bromination process intensification.

Treatment of wastewater containing o-phenylenediamine by ozone in a rotor-stator reactor

This work employed a novel rotor-stator reactor (RSR) to intensify the degradation process of o-phenylenediamine (o-PDA) by ozone. The effects of different operating parameters including initial pH, temperature, rotation speed, liquid volumetric flow rate and inlet ozone concentration on the removal efficiency of o-PDA were investigated in an attempt to establish the optimum conditions. The removal efficiency was evaluated in terms of degradation ratio and chemical oxygen demand (COD) reduction ratio of the o-PDA wastewater. Results indicate that the removal efficiency decreased with increasing liquid volumetric flow rate but increased with an increase in pH and inlet ozone concentration. Also, the removal efficiency increased up to a certain level with an increase in rotation speed and temperature. Additionally, a comparison experiment was carried out in a stirred tank reactor (STR), and the results show that the degradation and COD reduction ratios reached a maximum of 94.6% and 61.2% in the RSR as compared to 45.3% and 28.6% in the STR, respectively. This work demonstrates that ozone oxidation carried out in RSR may be a promising alternative for pre-treatment of o-PDA wastewater.