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Effects of Magnesium and Ferric Ions on Crystallization of Calcium Sulfate Dihydrate Under the Simulated Conditions of Wet Flue-gas Desulfurization

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Chemical Research in Chinese Universities 2008年第6期24卷 688-693页

作者： GAO Xiang HUO Wang ZHONG Yi LUO Zhong-yang CEN Ke-fa ni ming-jiang CHEN Le-ming State Key Laboratory of Clean Energy Utilization Institute of Thermal Energy and Power Engineering Zhejiang University Hangzhou 310027 P. R. China

The influences of magnesium and ferric ions in their different ratios on the rate of gypsum crystallization were studied under the conditions similar to those of wet flue-gas desulfurization（WFGD）. The results show that addition of both Mg^2＋ and Fe^3＋ increased induction time and decreased the growth efficiency up to 50% compared with the baseline（without impurities） depending on the concentration and the type of impurity. The effects of Mg^2＋ and Fe^3＋ on the surface energy and the rate of nucleation were estimated by employing the classical nucleation theory. The surface energy decreased by 8% and 14% with the addition of 0.02 mol/L magnesium or ferric ions, respectively, compared to the baseline. Mg^2＋ and Fe^3＋ made the growth rate of the （020）, （021） and （040） faces of gypsum crystal a much greater reduction, which leads to the formation of needle crystals compared to the baseline which favors the formation of plate or flakes. Furthermore, an edge detection program was developed to quantify the effects of impurities on the filtration rate of gypsum product. The results show that the inhibition efficiency of the presence of 0.02 mol/L Mg^2＋ and Fe^3＋ on the filtration rate of gypsum crystal ranges from 22% to 39%.

关键词： Calcium sulfate dihydrate Morphology Wet flue-gas desulfurization Filtration rate

Effects of inorganic chlorine source on dioxin formation using fly ash from a fluidized bed incinerator

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Journal of Environmental Sciences 2007年第6期19卷 756-761页

作者： LU Sheng-yong YAN Jian-hua LI Xiao-dong ni ming-jiang CEN Ke-fa DAI Hui-fen State Key Laboratory of Clean Energy Utilization Institute for Thermal Power Engineering Zhejiang University Hangzhou 310027 China School of Medicine Zhejiang University Hangzhou 310058 China

Chlorine source is indispensable for polychlorinated dibenzo-p-dioxin and furan （PCDD/F） formation during municipal solid waste （MSW） incineration. Inorganic chlorine compounds were employed in this study to investigate their effects on PCDD/F formation through heterogeneous synthesis on fly ash surfaces. A fly ash sample obtained from a fluidized bed incinerator was sieved to different size fractions which served as the PCDD/F formation sources. The capability of different metal chlorides which facilitate the formation of PCDDs/Fs was found to follow the trends： Na 〈 Mg 〈 K 〈 AI 〈 Ca, when two particle fractions of 〉177 μm and 104-125 μm were used in the experiments. However, the capability of NaCI, MgCl2 and KCI did not seem much different from each other, whereas CaCl2 and AlCl3 were much more active in PCDD/F formation. NaCl and MgCl2 were relatively effective to produce more PCDDs, while KC1, AICl3 and CaCl2 generated more PCDFs during heterogeneous reactions occurring on fly ash. 2,3,7,8-TCDF was the most significant contributor to the toxicity of the PCDDs/Fs formed from inorganic chlorine sources. Decreasing the sizes of fly ash particles led to more active formation of PCDDs/Fs when NaCl was used as inorganic chlorine in the experiment. The highest PCDDs/Fs produced from particles with size 〈37 μm, while the lowest PCDDs/Fs produced from particles with size 〉177μm. The toxicity generally increased with decreasing size of the fly ash particles. The formation of PCDDs was mainly facilitated by the two size fractions, 104-125 μm and 〈37μm, while the formation of PCDFs was favored by the two other size fractions, 〉177 μm and 53-104 μm.

关键词： fly ash inorganic chlorine source PCDDs/Fs heterogeneous synthesis

Study on pyrolysis and gasification of wood in MSW

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Journal of Environmental Sciences 2006年第2期18卷 407-415页

作者： ni ming-jiang XIAO Gang CHI Yong YAN Jian-hua MIAO Qi ZHU Wen-li CEN Ke-fa Institute for Thermal Power Engineering State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou 310027 China

In order to develop municipal solid waste（MSW） pyrolysis/gasification and melting technology with low emission and high efficiency, it was planed that all the main components in MSW and some typical kinds of MSW were pyrolyzed/gasified to propose an expert system for raw MSW. In this paper, wood, which was a prevalent component in MSW, was pyrolyzed and gasified in fluidized-bed reactors at different apparent excess air ratios （EARs）, temperatures and fluidizing velocities. For pyrolysis, with tem- perature increasing from 400℃ to 700℃, the yield of pyrolysis char decreased while that of pyrolysis gas increased （in this paper respectively from 28% to 20% and from 10% to 35%）, and when temperature was 500℃, the yield of pyrolysis tar reached the highest, up to 38% in this paper. It was the optimum for gasification when temperature was 600℃ and apparent EAR was 0.4. Under the experimental conditions of this paper, gasification efficiency achieved 73%, lower heat value（LHV） reached 5800 kJ/（Nm^3） and yield of syngas was 2.01 Nm^3/kg. Lower fluidizing velocity was useful to upgrade gasification efficiency and LHV of syngas for wood gasification. Based on the results, the reactive courses and mechanism were analyzed respectively for wood pyrolysis and gasification.

关键词： wood pyrolysis gasification municipal solid waste(MSW)

Fluidized-bed pyrolysis of waste bamboo

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第9期8卷 1495-1499页

作者： XIAO Gang ni ming-jiang HUANG He CHI Yong XIAO Rui ZHONG Zhao-ping CEN Ke-fa Key Lab. on Clean Coal Power Generation and Combustion Technology of Ministry of Education School of Energ3＂ and Environment Southeast University Nanjing 210096. China State Key Lab. of Clean Energy Utilization College of Mechanical and Energy Engineering Zhejiang University Hangzhou 310027 China College of Lfe Science and Pharmaceutical Engineering Nanjing University of Technology Nanjing 210009 China

Bamboo was a popular material substituting for wood, especially for one-off commodity in China. In order to recover energy and materials from waste bamboo, the basic characteristics of bamboo pyrolysis were studied by a thermogravimetric analyzer. It implied that the reaction began at 190-210℃, and the percentage of solid product deceased from about 25% to 17% when temperature ranged from 400℃ to 700℃. A lab-scale fluidized-bed furnace was setup to research the detailed properties of gaseous, liquid and solid products respectively. When temperature increased from 400℃ to 700℃, the mass percent of solid product decreased from 27% to 17% approximately, while that of syngas rose up from 19% to 35%. When temperature was about 500℃, the percentage of tar reached the top, about 31%. The mass balance of these experiments was about 93%-95%. It indicated that three reactions involved in the process： pyrolysis of exterior bamboo, pyrolysis of interior bamboo and secondary pyrolysis of heavy tar.

关键词： Bamboo Pyrolysis Fluidized beds Syngas Tar

Destruction of PCDD/Fs by gliding arc discharges

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Journal of Environmental Sciences 2007年第11期19卷 1404-1408页

作者： YAN Jian-hua PENG Zheng LU Sheng-yong DU Chang-ming LI Xiao-dong CHEN Tong ni ming-jiang CEN Ke-fa State Key Laboratory of Clean Energy Utilization Institute for Thermal Power Engineering Zhejiang University Hangzhou 310027 China Environmental Science and Engineering Sun Yat-Sen University Guangzhou 510275 China

PCDD/Fs have been become a serious issue because of their toxicological effects and associated adverse health implications. In this study, the gliding arc plasma was tested for treatment of polychlorinated dibenzo-p-dioxins （PCDDs） and polychlorinated dibenzofurans （PCDFs）, which was synthesized from pentachlorophenol in atmospheric condition at 350℃ with or without the catalysis of CuCl2. From the experiment, we found that the destruction efficiency of PCDD/F homologues after gliding was discharge ranged from 25% to 79%. This result demonstrates that gliding arc plasma is an effective technology to decompose PCDDs/Fs in flue gas. A plausible degradation mechanism for PCDD/Fs by gliding arc was discussed. Finally, a multistage reactor structure of gliding arc was proposed to upgrade removal efficiency for PCDD/Fs.

关键词： PCDD/Fs destruction gliding arc discharges, multistage reactor

Experimental study on MSW gasification and melting technology

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Journal of Environmental Sciences 2007年第11期19卷 1398-1403页

作者： XIAO Gang JIN Bao-sheng ZHONG Zhao-ping CHI Yong ni ming-jiang CEN Ke-fa XIAO Rui HUANG Ya-ji HUANG He Key Laboratory of Clean Coal Power Generation and Combustion Technology of Ministry of Education School of Energy and Environment Southeast University Nanjing 210096 China State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou 310027 China College of Life Science and Pharmaceutical Engineering Nanjing University of Technology Nanjing 210009 China

In order to develop municipal solid waste （MSW） gasification and melting technology, two preliminary experiments and a principle integrated experiment were fulfilled respectively. The gasification characteristics of MSW were studied at 500-750℃ when equivalence ratio （ER） was 0.2--0.5 using a fluidized-bed gasifier. When temperature was 550-700℃ and ER was 0.2--0.4, low heat value （LHV） of syngas reaches 4000-12000 kJ/Nm^3. The melting characteristics of fly ash were investigated at 1100-1460℃ using a fixed-bed furnace. It was proved that over 99.9% of dioxins could be decomposed and most heavy-metals could be solidified when temperature was 1100-1300℃. The principle integrated experiment was carried out in a fluidized-bed gasification and swirl-melting system. MSW was gasified etticiently at 550-650℃, swirl-melting furnace maintains at 1200-1300℃ stably and over 95% of fly ash could be caught by the swirl-melting furnace. The results provided much practical experience and basic data to develop MSW gasification and melting technology.

关键词： municipal solid waste (MSW) fluidized-bed gasification swirl-melting characteristics

Modern phenomics to empower holistic crop science, agronomy, and breeding research

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Journal of Genetics and Genomics 2024年第8期51卷 790-800页

作者： ni jiang Xin-Guang Zhu Institute of Genetics and Developmental Biology Chinese Academy of SciencesBeijing 100101China Center of Excellence for Molecular Plant Sciences Chinese Academy of SciencesShanghai 200032China

Crop phenomics enables the collection of diverse plant traits for a large number of samples along different time scales,representing a greater data collection throughput compared with traditional *** modern crop phenomics use different sensors to collect reflective,emitted,and fluorescence signals,etc.,from plant organs at different spatial and temporal *** multi-modal,high-dimensional data not only accelerates basic research on crop physiology,genetics,and whole plant systems modeling,but also supports the optimization of field agronomic practices,internal environments of plant factories,and ultimately crop *** challenges and opportunities facing the current crop phenomics research community include developing community consensus or standards for data collection,management,sharing,and processing,developing capabilities to measure physiological parameters,and enabling farmers and breeders to effectively use phenomics in the field to directly support agricultural production.

关键词： Crop phenomics High-throughput phenotyping Traits Crop designer breeding Agronomy

An improved initial rotor position estimation method using high-frequency pulsating voltage injection for PMSM

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Defence Technology（防务技术） 2024年第3期33卷 19-29页

作者： Yang jiang ming Cheng School of Electrical Engineering Southeast UniversityNanjing 210096China

High frequency pulsating voltage injection method is a good candidate for detecting the initial rotor position of permanent magnet synchronous ***,traditional methods require a large number of filters,which leads to the deterioration of system stability and dynamic *** order to solve these problems,a new signal demodulation method is proposed in this *** proposed new method can directly obtain the amplitude of high-frequency current,thus eliminating the use of filters,improving system stability and dynamic performance and saving the work of adjusting filter *** addition,a new magnetic polarity detection method is proposed,which is robust to current measurement ***,experiments verify the effectiveness of the method.

关键词： Initial position detection Signal demodulation algorithm Magnetic polarity detection Filter elimination

A Dielectric Multilayer Filter for Combining Photovoltaics with a Stirling Engine for Improvement of the Efficiency of Solar Electricity Generation

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Chinese Physics Letters 2011年第12期28卷 289-292页

作者： SHOU Chun-Hui LUO Zhong-Yang WANG Tao SHEN Wei-Dong ROSENGARTEN Gary WANG Cheng ni ming-jiang CEN Ke-Fa State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou 310027 State Key Laboratory of Modern Optical Instrumentation Zhejiang UniversityHangzhou 310027 School of Mechanical and Manufacturing Engineering University of New South WalesSydney 2052

In this Letter we outline a dielectric multilayer spectrally selective filter designed for solar energy *** optical performance of this 78-layer interference filter constructed by TiOx and SiO_(2) is presented.A hybrid system combining photovoltaic cells with a solar-powered Stirling engine using the designed filter is *** calculated results show the advantages of this spectrally selective method for solar power generation.

关键词： Engine Efficiency Solar