5 results on '"Hongru Pang"'
Search Results
2. Thermal and non-thermal mechanism of microwave irradiation on moisture content reduction of municipal sludge
- Author
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Binqi Rao, Jiangge Su, Shengjun Xu, Hongru Pang, Peng Xu, Yan Zhang, Jianwei Zhu, and Houde Tu
- Subjects
Environmental Engineering ,Sewage ,Ecological Modeling ,Myocardial Infarction ,Humans ,Water ,Microwaves ,Pollution ,Waste Management and Disposal ,Waste Disposal, Fluid ,Water Science and Technology ,Civil and Structural Engineering - Abstract
Both huge volume and high moisture content of municipal sludge have brought great troubles and attracted extensive concerns in the world. The bound water of sludge and pore clogging in the process of pressure filtration dewatering are two key factors influencing the deep-dewatering effect of municipal sludge. The results of this study suggest that microwave irradiation (MI) can be used to synchronously evaporate water, reduce the bound water of sludge and solve the blockage of sludge pore channels during the process filtration dewatering, which can greatly reduce the moisture content of municipal sludge. Low-field nuclear magnetic resonance, carbon dioxide gas absorption and desorption, and scanning electron microscope were synthetically used to detect the pore structure of sludge cakes. Thermogravimetric differential scanning calorimetry was used to detect binding energy to calculate moisture distribution. Thermal mechanism was revealed by dielectric constant, thermal conductivity, fractal dimensions, water saturation and porosity in different layers of sludge cake. The results showed that the bound water in sludge samples after MI was reduced by 19.4%, the pore fractal dimension was reduced from 2.955 to 2.867, the surface fractal dimension increased from 2.099 to 2.362 with the conditions of microwave power (700 w) and treat time (5 min). When the water saturation was close to 1, the dielectric constant of middle and outer layers was the main factor of heating, while the water saturation was close to 0, the main factor became the difference of thermal conductivity in middle and outer layers. Moreover, after MI, moisture content of sludge was greatly reduced from 68.4% to 40.1% for its thermal effect, further reduced to 34.1% by the continuous mechanical dewatering for its non-thermal effect which change the pore structure and moisture distribution. These conclusions are helpful to understand microwave thermal and non-thermal mechanism and shed light on new dewatering-drying integrated techniques of municipal sludge.
- Published
- 2022
3. Coupling mechanism and parameter optimization of sewage sludge dewatering jointly assisted by electric field and mechanical pressure
- Author
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Binqi Rao, Jiangge Su, Jing Xu, Shengjun Xu, Hongru Pang, Yan Zhang, Peng Xu, Boran Wu, Jiadi Lian, and Long Deng
- Subjects
Environmental Engineering ,Electricity ,Sewage ,Pressure ,Environmental Chemistry ,Water ,Pollution ,Waste Management and Disposal ,Waste Disposal, Fluid - Abstract
Pressurized electro-dewatering technology is considered to be one of the most effective methods for improving dewatering performance of sewage sludge. In this paper, four dewatering protocols were developed to further explore the coupling mechanism of sludge dewatering through mechanical pressure, electric field and their joint. The results showed that the dewatering performance of the four dewatering protocols were as follows: pressurized electro-dewatering with constant voltage gradient mode (G-PEDW) first mechanical dewatering then electro-dewatering mechanical dewatering electro-dewatering. The coupling mechanism was revealed from the perspectives of pore structure and moisture distribution of sludge cakes. The pore structure was discussed in detail from the whole pore size distribution and fractal dimension. The fractal dimension could quantitatively describe the change of pore structure. The moisture distribution was analyzed by the thermogravimetric differential scanning calorimetry test. The results showed that the electric field could reduce bound strength of moisture and produce new micro-pores to build more water flow paths, the water was discharged through interior capillary channels, and mechanical pressure could accelerate the water removing process. Response surface method was used to establish an empirical prediction model of G-PEDW, and discussed the selection of optimal parameters. The R-square values of mathematical models of moisture content and energy consumption were as high as 0.9863 and 0.9838, respectively, which was more advanced than other mathematical models. Experiments showed that G-PEDW could reduce the time to 20 min or reduce the energy consumption to 7.1 Wh/kg
- Published
- 2021
4. Multiphysics Simulation Research on Microwave Drying of Municipal Sludge
- Author
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Xu Shengjun, Gongqin Wang, Jiadi Lian, Long Deng, Hongru Pang, and Binqi Rao
- Subjects
Materials science ,Computer simulation ,Field (physics) ,Multiphysics ,Electric field ,Nuclear engineering ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Water content ,Intensity (heat transfer) ,Microwave ,Microwave cavity - Abstract
The COMSOL Multiphysics software was used to perform numerical simulation analysis on the microwave drying process of pressurized sludge, and the influence of sludge thickness, moisture content, microwave power and sludge position on the electric field and sludge temperature field in the microwave cavity was studied. The results show that the microwave power has a great influence on the electric field and temperature field, while the sludge thickness, moisture content and position of the sludge does little. With the increase of the microwave power, the intensity of the electric field in the microwave cavity and the heating rate of the sludge increases. The optimal process conditions for the microwave drying of the pressurized sludge after numerical simulation are the microwave power of 1000 W, and the sludge is in the center of the cavity.
- Published
- 2021
5. Pore-scale model and dewatering performance of municipal sludge by ultrahigh pressurized electro-dewatering with constant voltage gradient
- Author
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Feibiao Fan, Shuxia Qiu, Peng Xu, Xu Wu, Binqi Rao, Jiangge Su, Gongqin Wang, Jicheng Zhang, Jianwei Zhu, Xilong Lu, and Hongru Pang
- Subjects
Work (thermodynamics) ,Capillary pressure ,Environmental Engineering ,Materials science ,0208 environmental biotechnology ,02 engineering and technology ,010501 environmental sciences ,Wastewater ,01 natural sciences ,Waste Disposal, Fluid ,Differential scanning calorimetry ,Electricity ,Electric field ,Waste Management and Disposal ,Water content ,0105 earth and related environmental sciences ,Water Science and Technology ,Civil and Structural Engineering ,Moisture ,Petroleum engineering ,Sewage ,Ecological Modeling ,Water ,Energy consumption ,Pollution ,Dewatering ,020801 environmental engineering - Abstract
The disposal of huge municipal sludge with high moisture content has led to numerous energy consumption and brought extensive concerns in the world. In this paper, three dewatering modes, ultrahigh-pressure mechanical dewatering mode (UMDW), pressurized electro-dewatering (PEDW) with constant voltage mode (U-PEDW) and constant voltage gradient mode (G-PEDW) were performed on a self-designed pressurized electro-dewatering apparatus for municipal sludge. The pore structures and moisture distributions were detected by low-field nuclear magnetic resonance technology. Meanwhile, the moisture distributions and quantitative bound strength were analyzed by the thermogravimetric differential scanning calorimetry test. Moreover, a pore-scale electro-osmosis model was accordingly developed based on the fractal characteristics of pore size distribution. Finally, the effect of dewatering modes and operating parameters on moisture content and energy consumption were examined in detail. The results indicate that the pore-scale electro-osmosis model show good consistency with experimental data. The electric field can drive the middle-layers-water to overcome the capillary pressure, and make G-PEDW removing more water than UMDW. The moisture content of dewatered municipal sludge by G-PEDW and U-PEDW reaches to 28.41% and 27.33%, respectively. Furthermore, the energy consumption of G-PEDW is 189.62Wh/kg.H2O, it is much lower than that of U-PEDW. Therefore, the G-PEDW mode with low moisture content and less energy consumption indicates best dewatering performance compared with UMDW and U-PEDW modes. The present work is helpful to understand the dewatering mechanisms of G-PEDW and provides useful guidelines for G-PEDW dewatering technology.
- Published
- 2020
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