TiO_(2) is a promising photocatalyst,but its practical use is restricted by its low catalytic efficiency caused by the large particle size and uneven size distribution,which arise from the limited contact area of the ...TiO_(2) is a promising photocatalyst,but its practical use is restricted by its low catalytic efficiency caused by the large particle size and uneven size distribution,which arise from the limited contact area of the liquid-liquid interface during synthesis.Impinging stream-rotating packed bed(IS-RPB)reactors,which are used for process intensification,overcome the mixing limitation of traditional stirred-tank reactors and provide a micromixing environment at the molecular scale for the two liquid phases,which can reduce the particle size and distribution range.Cu/N-TiO_(2) nanoparticles were prepared in an IS-RPB reactor by the one-step precipitation method using urea as the nitrogen source,titanyl sulfate as the titanium source,copper chloride as the copper source,and ammonium hydroxide as the precipitant.The particle size of the photocatalyst was about 11.40 nm with a narrow size distribution measured by scanning electron microscopy and transmission electron microscopy.X-ray photoelectron spectroscopy showed that N replaced some O and was uniformly dispersed in the TiO_(2) lattice as interstitial and substitutional N.Cu replaced some Ti and was present as Cu^(2+).The synergistic effects of these two elements formed a new impurity energy level and reduced the band gap energy of the TiO_(2) nanoparticles.The specific surface area of the Cu/N-TiO_(2) nanoparticles was 152.97 m^(2)/g.The effects of the main factors on the degradation rate were studied,and the removal efficiency reached 100%under the optimal operating conditions after 2 h ultraviolet irradiation.The electron paramagnetic resonance measurements showed that the superoxide radical played a main role in the degradation process,whereas the photogenerated holes and hydroxyl radicals had weak effects.展开更多
The removal of hydrogen sulfide from gas plays an important role in rational utilization of resources and environ- mental protection. In this paper, the process of hydrogen sulfide removal by wet oxidation method in a...The removal of hydrogen sulfide from gas plays an important role in rational utilization of resources and environ- mental protection. In this paper, the process of hydrogen sulfide removal by wet oxidation method in a rotating packed bed was investigated in a scale for treating 10 000 Nm3/h of gas. On the basis of studying the influence of the species and con- centration of alkali source, the liquid/gas volume ratio, the high gravity factor, and the hydrogen sulfide content in feed gas on the desulfurization effect, the suitable technological conditions were obtained. The hydrogen sulfide removal efficiency could reach 98.0% under these conditions. The results of continuous operation of process facilities showed that the high gravity method has many merits including higher desulfurization rate, good stability in operation, lower liquid/gas volume ratio, greater operation elasticity, and apparent energy saving effects.展开更多
Optimization of factors influencing the experiments on reactions involving 8 different chelating agents and soluble Fe(III)/Fe(II) salts was carried out to yield chelated iron complexes. A combination of optimized inf...Optimization of factors influencing the experiments on reactions involving 8 different chelating agents and soluble Fe(III)/Fe(II) salts was carried out to yield chelated iron complexes. A combination of optimized influencing factors has resulted in a Fe chelating capacity of the iron-based desulfurization solution to be equal to 6.83—13.56 g/L at a redox potential of 0.185—0.3. The desulfurization performance of Fe(III)/Fe(II) chelating agents was investigated on a simulated sulfur-containing industrial gas composed of H2 S and N2 in a cross-flow rotating packed bed. Test results have revealed that the proposed iron-based desulfurization solution showed a sulfur removal efficiency of over 99% along with a Fe chelating capacity exceeding 1.35 g/L. This desulfurization technology which has practical application prospect is currently in the phase of commercial scale-up study.展开更多
By using a mixture of N2 and H2S as the simulated APG(associated petroleum gas), the desulfurization experiment was performed in a cross-flow rotating packed bed(RPB) based on the chelated iron oxidation-reduction met...By using a mixture of N2 and H2S as the simulated APG(associated petroleum gas), the desulfurization experiment was performed in a cross-flow rotating packed bed(RPB) based on the chelated iron oxidation-reduction method. In order to determine the operating conditions of the system, the effects of the concentration of Fe3+ ions(ranging from 0.1 to 0.2 mol/L), the liquid-gas volume ratio(ranging from 15 to 25 L/m3) and the high gravity factor(ranging from 36 to 126) on the removal of H2 S were studied by means of the Box-Behnken design(BBD) under response surface methodology(RSM). The overall results have demonstrated that the BBD with an experimental design can be used effectively in the optimization of the desulfurization process. The optimal conditions based on both individualized and combined responses(at a Fe3+ ion concentration of 0.16 mol/L, a liquid-gas volume ratio of 20.67 L/m3 and a high gravity factor of 87) were found. Under this optimum condition, the desulfurization efficiency could reach 98.81% when the H2 S concentration was 7 g/m3 in APG. In this work, the sulfur product was analyzed by X-ray diffraction(XRD), scanning electron microscopy(SEM) and the energy dispersive X-ray spectrometer(EDX). The results of analysis show that the sulfur is made of the high-purity orthorhombic crystals, which are advantageous to environmental conservation.展开更多
The rotating packed bed(RPB), mainly including the countercurrent-flow RPB(Counter-RPB) and the crosscurrentflow RPB(Cross-RPB) that are classified from the perspective of gas-liquid contact style, is a novel process ...The rotating packed bed(RPB), mainly including the countercurrent-flow RPB(Counter-RPB) and the crosscurrentflow RPB(Cross-RPB) that are classified from the perspective of gas-liquid contact style, is a novel process intensification device. A significant measurement standard for evaluating the performance of RPB is the mass transfer effect. In order to compare the mass transfer characteristics of Counter-RPB and Cross-RPB with the same size, the liquid volumetric mass transfer coefficient(k_La_e) and effective interfacial area(a_e) were measured under identical operating conditions. Meanwhile, the comparison of comprehensive mass transfer performance was conducted using the ratio of ΔP(pressure drop) to kLae as the standard. Experimental results indicated that kLae and ae increased with the increase in liquid spray density q, gas velocity u, and high gravity factor β. Furthermore, compared with the Cross-RPB, the Counter-RPB has higher liquid volumetric mass transfer coefficient and slightly larger effective interfacial area. The experimental results of comprehensive mass transfer performance showed that the Counter-RPB had higher ΔP/k_La_e than the Cross-RPB with changes in liquid spray density and high gravity factor, and there exists a turning point at 0.71 m/s accompanied by a variation with gas velocity. Moreover, the relative error of experimental value to calculated value, which was computed by the correlative expressions of kLae, was less than 5 %. In conclusion, the mass transfer characteristics of RPB are deeply impacted by the manner in which the flows are established and the Cross-RPB would have a great potential for industrial scale-up applications.展开更多
基金supported by the Natural Science Foundation of Shanxi Province (201901D211222)the Natural Science Foundation of the Shanxi Province of China (201901D111173)the Scientific and Technological Innovation Programs of Higher Education Institution in Shanxi (2019L0515)
文摘TiO_(2) is a promising photocatalyst,but its practical use is restricted by its low catalytic efficiency caused by the large particle size and uneven size distribution,which arise from the limited contact area of the liquid-liquid interface during synthesis.Impinging stream-rotating packed bed(IS-RPB)reactors,which are used for process intensification,overcome the mixing limitation of traditional stirred-tank reactors and provide a micromixing environment at the molecular scale for the two liquid phases,which can reduce the particle size and distribution range.Cu/N-TiO_(2) nanoparticles were prepared in an IS-RPB reactor by the one-step precipitation method using urea as the nitrogen source,titanyl sulfate as the titanium source,copper chloride as the copper source,and ammonium hydroxide as the precipitant.The particle size of the photocatalyst was about 11.40 nm with a narrow size distribution measured by scanning electron microscopy and transmission electron microscopy.X-ray photoelectron spectroscopy showed that N replaced some O and was uniformly dispersed in the TiO_(2) lattice as interstitial and substitutional N.Cu replaced some Ti and was present as Cu^(2+).The synergistic effects of these two elements formed a new impurity energy level and reduced the band gap energy of the TiO_(2) nanoparticles.The specific surface area of the Cu/N-TiO_(2) nanoparticles was 152.97 m^(2)/g.The effects of the main factors on the degradation rate were studied,and the removal efficiency reached 100%under the optimal operating conditions after 2 h ultraviolet irradiation.The electron paramagnetic resonance measurements showed that the superoxide radical played a main role in the degradation process,whereas the photogenerated holes and hydroxyl radicals had weak effects.
基金the Shanxi Provin-cial Youth Science and Technology Research Fund (No.2008021009-2) for the financial support to this project
文摘The removal of hydrogen sulfide from gas plays an important role in rational utilization of resources and environ- mental protection. In this paper, the process of hydrogen sulfide removal by wet oxidation method in a rotating packed bed was investigated in a scale for treating 10 000 Nm3/h of gas. On the basis of studying the influence of the species and con- centration of alkali source, the liquid/gas volume ratio, the high gravity factor, and the hydrogen sulfide content in feed gas on the desulfurization effect, the suitable technological conditions were obtained. The hydrogen sulfide removal efficiency could reach 98.0% under these conditions. The results of continuous operation of process facilities showed that the high gravity method has many merits including higher desulfurization rate, good stability in operation, lower liquid/gas volume ratio, greater operation elasticity, and apparent energy saving effects.
基金financially supported by the Natural Science Fundation of China (No.21376229) the Science and Technology Development Plan of Shanxi Province,China (No.20130321035-02)
文摘Optimization of factors influencing the experiments on reactions involving 8 different chelating agents and soluble Fe(III)/Fe(II) salts was carried out to yield chelated iron complexes. A combination of optimized influencing factors has resulted in a Fe chelating capacity of the iron-based desulfurization solution to be equal to 6.83—13.56 g/L at a redox potential of 0.185—0.3. The desulfurization performance of Fe(III)/Fe(II) chelating agents was investigated on a simulated sulfur-containing industrial gas composed of H2 S and N2 in a cross-flow rotating packed bed. Test results have revealed that the proposed iron-based desulfurization solution showed a sulfur removal efficiency of over 99% along with a Fe chelating capacity exceeding 1.35 g/L. This desulfurization technology which has practical application prospect is currently in the phase of commercial scale-up study.
基金financially supported by the National Science Foundation of China (No. 21376229)the Science and Technology Development Plan of Shanxi Province (No. 20130321035-02)
文摘By using a mixture of N2 and H2S as the simulated APG(associated petroleum gas), the desulfurization experiment was performed in a cross-flow rotating packed bed(RPB) based on the chelated iron oxidation-reduction method. In order to determine the operating conditions of the system, the effects of the concentration of Fe3+ ions(ranging from 0.1 to 0.2 mol/L), the liquid-gas volume ratio(ranging from 15 to 25 L/m3) and the high gravity factor(ranging from 36 to 126) on the removal of H2 S were studied by means of the Box-Behnken design(BBD) under response surface methodology(RSM). The overall results have demonstrated that the BBD with an experimental design can be used effectively in the optimization of the desulfurization process. The optimal conditions based on both individualized and combined responses(at a Fe3+ ion concentration of 0.16 mol/L, a liquid-gas volume ratio of 20.67 L/m3 and a high gravity factor of 87) were found. Under this optimum condition, the desulfurization efficiency could reach 98.81% when the H2 S concentration was 7 g/m3 in APG. In this work, the sulfur product was analyzed by X-ray diffraction(XRD), scanning electron microscopy(SEM) and the energy dispersive X-ray spectrometer(EDX). The results of analysis show that the sulfur is made of the high-purity orthorhombic crystals, which are advantageous to environmental conservation.
基金supported by the National Key R&D Program of China:The ultra-low emission control technology for coal-fired industrial boilers(2016YFC0204103)the Provincial Key R&D Program of Shanxi:R&D of the coal-fired industrial boiler smoke ultra-low emission technology and equipment(201703D111018)
文摘The rotating packed bed(RPB), mainly including the countercurrent-flow RPB(Counter-RPB) and the crosscurrentflow RPB(Cross-RPB) that are classified from the perspective of gas-liquid contact style, is a novel process intensification device. A significant measurement standard for evaluating the performance of RPB is the mass transfer effect. In order to compare the mass transfer characteristics of Counter-RPB and Cross-RPB with the same size, the liquid volumetric mass transfer coefficient(k_La_e) and effective interfacial area(a_e) were measured under identical operating conditions. Meanwhile, the comparison of comprehensive mass transfer performance was conducted using the ratio of ΔP(pressure drop) to kLae as the standard. Experimental results indicated that kLae and ae increased with the increase in liquid spray density q, gas velocity u, and high gravity factor β. Furthermore, compared with the Cross-RPB, the Counter-RPB has higher liquid volumetric mass transfer coefficient and slightly larger effective interfacial area. The experimental results of comprehensive mass transfer performance showed that the Counter-RPB had higher ΔP/k_La_e than the Cross-RPB with changes in liquid spray density and high gravity factor, and there exists a turning point at 0.71 m/s accompanied by a variation with gas velocity. Moreover, the relative error of experimental value to calculated value, which was computed by the correlative expressions of kLae, was less than 5 %. In conclusion, the mass transfer characteristics of RPB are deeply impacted by the manner in which the flows are established and the Cross-RPB would have a great potential for industrial scale-up applications.
