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Effect of bed size on the gas-solid flow characterized by pressure fluctuations in bubbling fluidized beds

Particuology 2019年第6期17卷 1-9页

作者： Jie Xiang yanguo zhang Qinghai Li Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University-University of Waterloo Joint Research Center for Micro/Nano Energy&1 Environment TechnologyDepartment of Energy and Power EngineeringTsinghua UniversityBeijing 100084China

Pressure fluctuations in four bubbling fluidized beds having different bed sizes (three square cross-sections of 5, 10, and 15 cm in side length, and one rectangular cross-section of 2 × 10 cm2) were measured at four axial positions (P1, P2, P3, and P4). Several characteristic indicators of the flow specifically of the pressure were calculated. In terms of these characteristic indicators, the effect of bed size on flow behavior was investigated. The results show that in the fully fluidized state, the pressure drop is slightly higher in smaller beds, but the pressure drops in the 10- and 15-cm beds are close. The 15-cm bed has the lowest pressure-fluctuation amplitude. The amplitudes at P1 and P2 in the lower part of the bed are very close for bed sizes below 10 cm, but the amplitude at P3 near the bed surface increases with decreasing bed size. No general trend was observed regarding the effect of bed size on skewness and kurtosis of the pressure for all four axial heights. For the average, standard deviation, skewness, and kurtosis of the pressure at P4, the values are close for the two small beds (2 × 10 and 5 × 5 cm2) and the two large beds (10 × 10 and 15 × 15 cm2), and hence the effect of bed size separates the beds into two groups. In the fully fluidized state, for P1, P2, and P3, the Kolmogorov entropy and the dominant frequency both increase with increasing bed size, but in the pseudo-2D bed both are between the values for the 5- and 10-cm beds.

关键词： Bubbling fluidized bed Pressure fluctuation Bed size Time-series analysis Dominant frequency Kolmogorov entropy

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Breaking the temperature limit of hydrothermal carbonization of lignocellulosic biomass by decoupling temperature and pressure

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Green Energy & Environment 2023年第4期8卷 1216-1227页

作者： Shijie Yu Xiaoxiao Yang Qinghai Li yanguo zhang Hui Zhou Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Beijing Key Laboratory of CO_(2) Utilization and Reduction TechnologyDepartment of Energy and Power EngineeringTsinghua UniversityBeijing100084China

Hydrothermal carbonization(HTC) of lignocellulosic biomass is a promising technology for the production of carbon materials with negative carbon emissions. However, the high reaction temperature and energy consumption have limited the development of HTC technology. In conventional batch reactors, the temperature and pressure are typically coupled at saturated states. In this study, a decoupled temperature and pressure hydrothermal(DTPH) reaction system was developed to decrease the temperature of the HTC reaction of lignocellulosic biomass(rice straw and poplar leaves). The properties of hydrochars were analyzed by scanning electron microscopy(SEM), Fourier transform infrared(FTIR) spectroscopy, X-ray photoelectron spectroscopy(XPS), Raman spectroscopy, X-ray diffraction(XRD), thermogravimetric analyzer(TGA), etc. to propose the reaction mechanism. The results showed that the HTC reaction of lignocellulosic biomass could be realized at a low temperature of 200℃ in the DTPH process, breaking the temperature limit(230℃) in the conventional process. The DTPH method could break the barrier of the crystalline structure of cellulose in the lignocellulosic biomass with high cellulose content, realizing the carbonization of cellulose and hemicellulose with the dehydration, unsaturated bond formation, and aromatization. The produced hydrochar had an appearance of carbon microspheres, with high calorific values, abundant oxygen-containing functional groups, a certain degree of graphitization, and good thermal stability. Cellulose acts not only as a barrier to protect itself and hemicellulose from decomposition, but also as a key precursor for the formation of carbon microspheres. This study shows a promising method for synthesizing carbon materials from lignocellulosic biomass with a carbon-negative effect.

关键词： Biomass Lignocellulose Hydrothermal treatment Hydrochar Carbon materials

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Selective hydrodeoxygenation of guaiacol to cyclohexanol using activated hydrochar-supported Ru catalysts

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Frontiers of Chemical Science and Engineering 2024年第5期18卷 13-22页

作者： Kaile Li Shijie Yu Qinghai Li yanguo zhang Hui Zhou Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Beijing Key Laboratory of CO_(2) Utilization and Reduction TechnologyDepartment of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Department of Chemical and Biomolecular Engineering National University of SingaporeSingapore117585Singapore

Lignin,an abundant aromatic polymer in nature,has received significant attention for its potential in the production of bio-oils and chemicals owing to increased resource availability and environmental *** hydrodeoxygenation of guaiacol,a lignin-derived monomer,can produce cyclohexanol,a nylon precursor,in a carbon-negative and environmentally friendly *** study explored the porous properties and the effects of activation methods on the Ru-based catalyst supported by environmentally friendly and cost-effective *** selective cleavage of C_(ary)-O bonds was achieved under mild conditions(160°C,0.2 MPa H_(2),and 4 h),and alkali activation further improved the catalytic *** characterization methods revealedthat hydrothermal treatment and alkali activation relatively contributed to the excellent performance of the catalysts and influenced their porous structure and Ru dispersion.X-ray photoelectron spectroscopy results revealed an increased formation of metallic ruthenium,indicating the effective regulation of interaction between active sites and *** synergistic approach used in this study,involving the valorization of cellulose-derived hydrochar and the selective production of nylon precursors from lignin-derived guaiacol,indicated the comprehensive and sustainable utilization of biomass resources.

关键词： hydrochar guaiacol cyclohexanol activation full-component utilization

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New possibility for PET plastic recycling by a tailored hydrolytic enzyme

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Green Energy & Environment 2024年第2期9卷 163-165页

作者： Shijie Yu Qinghai Li yanguo zhang Hui Zhou Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Beijing Key Laboratory of CO_(2)Utilization and Reduction TechnologyDepartment of Energy and Power EngineeringTsinghua UniversityBeijing 100084China

Plastic waste puts a huge burden on the ecosystem due to the current lack of mature recycling ***(ethylene terephthalate)(PET)is one of the most produced plastics in the *** decomposition holds the promise of recovering monomers from PET plastic,and the monomers can be used to regenerate new PET ***,there are still limitations in the activity and thermal stability of the existing PET *** recent study by Lu et *** a novel PET hydrolase via machine learning-aided *** obtained PET hydrolase showed excellent activity and thermal stability in the hydrolysis of PET and is capable of directly degrading large amounts of postconsumer PET *** approach provides an effective method for recycling PET waste and is expected to improve the current state of plastic pollution worldwide.

关键词： Plastic waste Poly(ethylene terephthalate) Hydrolysis Machine learning Enzymatic depolymerization Hydrolases

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Study on drying and combustion process in grate-CFB incinerator

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Science China(Technological Sciences) 2009年第5期52卷 1153-1160页

作者： QingHai Li yanguo zhang MeiQian Chen AiHong Meng ChangHe Chen Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University Beijing 100084 China School of Mechanical Electronical and Control Engineering Beijing Jiaotong University Beijing 100044 China

The drying and combustion process in the combined grate and circulating fluidized bed (grate-CFB) municipal solid waste (MSW) incinerator was investigated experimentally and mathematically. The drying grate bed was simulated by a muffle furnace, which could be controlled at a constant temperature level. The kind of wastes, thickness of waste layer fed and temperature were chosen as the adjustable parameters to study their effect on the drying process. The experimental results indicated that the hydrophilic wastes were more difficult to be dried than the hydrophobic wastes. The higher the temperature is the easier the waste is to be dried. The thinner waste layer is favorable to drying the waste. The pyrolysis experiment in the furnace showed that the higher temperature level could reduce the conversion rate of carbon to carbon monoxide. The semi-empirical mathematical model that included the bed material distribution submodel, volatile matter release submodel, carbon particle combustion submodel and so on was proposed. A 260 t/d grate-CFB incinerator was modeled and the model predicted bulk density agreed with the measured value from industrial field test. The predicted flue gas (e.g. CO2, CO) concentration deviated slightly from the industrial test data. The parameters and variables used in the model were determined by the experiments or practical field test. This model can be used to design the grate-CFB incinerator and guide its operation.

关键词： drying waste incineration grate-CFB combustion model

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Aerosol containment by airflow in biosafety laboratories

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Journal of Biosafety and Biosecurity 2019年第1期1卷 63-67页

作者： Xin Feng yanguo zhang Zhonglin Xu Donglin Song Guoqing Cao Lei Liang China Academy of Building Research Co. Ltd.30 North 3rd Ring East Rd.Beijing 100013China Wuhan Institute of Virology China Academy of Science44 Xiao Hong Shan Middle DistrictWu Han 430071China

In this paper,the progress and research related to aerosol containment by airflow in containment environments,e.g.,biosafety laboratories,are introduced from a mechanical engineering view.A good airdistribution strategy in the room,a reasonable and stable pressure gradient in the containment area,and a necessary buffer room comprise the integral parts for regulating the air flow and providing the necessary *** optimal air-distribution strategy would reduce the residence time of the bioaerosol in the lab room and lower the exposure risk of the work *** pressure difference between adjacent rooms provides sufficient isolation protection when the door is ***,an unfavorable air exchange would occur when the door is open,owing to door movement,passing people,or a tiny temperature difference.A buffer room is therefore necessary to offset the negative impact and maintain the containment effect.

关键词： Aerosol Containment Biosafety

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Glycerolipid Profiling of Yellow Sarson Seeds Using Ultra High Performance Liquid Chromatography Coupled to Triple Time-of-Flight Mass Spectrometry

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Horticultural Plant Journal 2017年第4期3卷 141-150页

作者： ZHENG Shuning zhang yanguo LIU Guangyang LV Jun LIU Zhongxiao XU Xiaomin LI Lingyun XU Donghui Institute of Vegetables and Flowers Chinese Academy of Agricultural Sciences Risk Assessment Laboratory for Vegetables Quality and SafetyMinistry of Agriculture (Beijing) Key Laboratory of Horticultural Crop Biology and Germplasm Creation of Ministry of Agriculture

Yellow sarson(Brassica rapa ssp. trillocularis) is an important rapeseed-mustard species of Brassica rapa due to its high seed oil content. Glycerolipids and fatty acid composition affect seed germination and determine the quality of seed oil. To date, no information is available on the composition of individual glycerolipids in this species. Therefore, in this study the glycerolipid profiling of yellow sarson seeds was performed using ultra high performance liquid chromatography coupled to triple time-of-flight mass spectrometry(UPLC-Triple-TOF-MS).A fast and efficient chromatographic separation of glycerolipids was accomplished based on an UPLCTMBEH C8 column within 22 *** ESI positive ion mode, TOF-MS scan-information dependent acquisition-product ion scan was carried out to acquire both high resolution MS and MS/MS information from one injection. According to MS/MS spectra, predominant fragmentation patterns of glycerolipids were elucidated in detail. Based on retention time, accurate mass, isotopic distribution, and fragmentation patterns, the composition of 144 glycerolipids and fatty acids were finally identified in yellow sarson seeds, including 77 triacylglycerols, 32 diacylglycerols, 18sulfoquinovosyl-diacylglycerols, 5 monogalactosyl-diaclyglycerols, and 12 digalactosyl-diacylglycerols. Of them, the most abundant glycerolipids in yellow sarson seeds were triacylglycerols, the major storage form of seed oil in plants. In addition, diacylglycerols were found as a minor component of glycerolipids. The lowest amounts of glycerolipids detected in seeds were glycosyl-acylglycerols. The results revealed the composition and relative content of glycerolipids in yellow sarson seeds, which will provide a more comprehensive assessment of the quality of seed oil and also help to select functional cultivars with higher beneficial glycerolipids. This profiling method has the advantages of high throughput, high sensitivity and good accuracy, which will provide a relia

关键词： yellow sarson seed glycerolipid profiling UPLC-triple-TOF-MS fragmentation pattern

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Investigation of heavy metal partitioning influenced by flue gas moisture and chlorine content during waste incineration

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Journal of Environmental Sciences 2010年第5期22卷 760-768页

作者： Qinghai Li,Aihong Meng,Jinyan Jia,yanguo zhang Department of Thermal Engineering,Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education of China,Tsinghua University,Beijing 100084,China. Department of Thermal Engineering Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education of China Tsinghua University Beijing 100084 China

The impact of moisture on the partitioning of the heavy metals including Pb,Zn,Cu and Cd in municipal solid waste （MSW） was studied in a laboratory tubular furnace.A thermodynamic investigation using CHEMKIN software was performed to compare the experimental *** waste,representative of typical MSW with and without chlorine compounds,was burned at the background temperature of 700 and 950°C,*** the absence of chlorine,the moisture content has no evident effect on the volatility of Pb,Zn and Cu at either 700 or 950°C,however,as flue gas moisture increasing the Cd distribution in the bottom ash increased at 700°C and reduced at 950°C,*** the presence of chlorine,the flue gas moisture reduced the volatility of Pb,Zn and Cu due to the transformation of the more volatile metal chlorides into less volatile metal oxides,and the reduction became significant as chlorine content *** Cd,the chlorine promotes its volatility through the formation of more volatile CdCl *** a result,the increased moisture content increases the Pb,Zn,Cu and Cd concentrations in the bottom ash,which limits the utilization of the bottom ash as a construction ***,in order to accumulate heavy metals into the fly ash,MSW should be dried before incineration.

关键词： heavy metals partitioning moisture chlorine municipal solid waste incineration

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Light collection of the POLAR detector

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Science China(Physics,Mechanics & Astronomy) 2010年第S1期53卷 43-46页

作者： DONG YongWei,LI yanguo,WU BoBing,zhang YongJie & zhang ShuangNan Key Laboratory of Particle Astrophysics,Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China

POLAR is a compact polarimeter dedicated to measuring the polarization of GRBs between 50-350 *** light collection of 200 mm×6 mm×6 mm plastic bars has been simulated and optimized in order to get uniform response to X-rays at different points along one single *** to the Monte Carlo results,the amplitude uniformity strongly depends on the level of polishing of the scintillator surface and the covering.A uniformity of 89% is achieved with a prototype constructed by a non position-sensitive PMT and an array of 4×4 bars.

关键词： plastic scintillator light collection gamma-ray burst polarimeter

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SVOM gamma ray monitor

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Science China(Physics,Mechanics & Astronomy) 2010年第S1期53卷 40-42页

作者： DONG YongWei,WU BoBing,LI yanguo,zhang YongJie & zhang ShuangNan Key Laboratory of Particle Astrophysics,Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China

The space-based multi-band astronomical Variable Object Monitor(SVOM) mission is dedicated to the detection,localization and broad-band study of gamma-ray bursts(GRBs) and other high-energy transient *** gamma ray monitor(GRM) onboard is designed to observe GRBs up to 5 *** this instrument,one of the key GRB parameters,Epeak,can be easily measured in the hard X-ray *** can achieve a detection rate of 100 GRBs per year which ensures the scientific output of SVOM.

关键词： gamma-ray burst Epeak triple phoswich

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