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Impact of individual acid flue gas components on mercury capture by heat-treated activated carbon

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第9期13卷 700-708页

作者： Jian-ming ZHENG Jin-song ZHOU zhong-yang luo Ke-fa CEN State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou 310027China School of Mechanical Engineering Jimei UniversityXiamen 361021China

Elemental mercury capture on heat-treated activated carbon （TAC） was studied using a laboratory-scale fixed bed reactor. The capability of TAC to perform Hg0 capture under both N2 and baseline gas atmospheres was studied and the effects of common acid gas constituents were evaluated individually to avoid complications resulting from the coexistence of multiple components. The results suggest that surface functional groups （SFGs） on activated carbon （AC） are vital to Hg0 capture in the absence of acid gases. Meanwhile, the presence of acid gas components coupled with defective graphitic lattices on TAC plays an important role in effective Hg0 capture. The presence of HC1, NO2, and NO individually in basic gases markedly enhances Hg0 capture on TAC due to the heterogeneous oxidation of Hg0 on acidic sites created on the carbon surface and catalysis by the defective graphitic lattices on TAC. Similarly, the presence of SO2 improves Hg0 capture by about 20%. This improvement likely results from the deposition of sulfur groups on the AC surface and oxidation of the elemental mercury by SO2 due to catalysis on the carbon surface. Furthermore, O2 exhibits a synergistic effect on Hg0 oxidation and capture when acid gases are present in the flue gases.

关键词： Flue gases Mercury Activated carbon (AC)

Influence of ash composition on the sintering behavior during pressurized combustion and gasification process

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第3期13卷 230-238页

作者： Ni-jie JING Qin-hui WANG Yu-kun yang Le-ming CHENG zhong-yang luo Ke-fa CEN State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou 310027 China

To determine the ash characteristics during fluidized bed combustion and gasification purposes, the investigation of the impacts of chemical composition of Jincheng coal ash on the sintering temperature was conducted. A series of experiments on the sintering behavior at 0.5 MPa was performed using the pressurized pressure-drop technique in the combustion and gasification atmospheres. Meanwhile, the mineral transformations of sintered ash pellets were observed using X-ray diffractometer （XRD） analyzer to better understand the experimental results. In addition, quantitative XRD and field emission scanning electron microscope/energy dispersive X-ray spectrometer （FE-SEM/EDS） analyses of ash samples were used for clarifying the detailed ash melting mechanism. These results show that the addition of Fe203 can obviously reduce the sintering temperatures under gasification atmospheres, and only affect a little the sintering temperature under combustion atmosphere. This may be due to the presence of iron-bearing minerals, which will react with other ash compositions to produce low-melting-point eutectics. The FE-SEM/EDS analyses of ash samples with Fe203 additive show consistent results with the XRD measurements. The CaO and Na20 can reduce the sintering temperatures under both the combustion and gasification atmospheres. This can be also contributed to the formation of low-melting-point eutectics, decreasing the sintering temperature. Moreover, the fluxing minerals, such as magnetite, anhydrite, muscovite, albite and nepheline, contribute mostly to the reduction of the sintering temperature while the feldspar minerals, such as anorthite, gehlenite and sanidine, can react with other minerals to produce low-melting-point eutectics, and thereby reduce the sintering temperatures.

关键词： Ash composition Sintering temperature X-ray diffractometer (XRD) Field emission scanning electron microscope/energy dispersive X-ray spectrometer (FE-SEM/EDS)

Development of non-premixed porous inserted regenerative thermal oxidizer

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第9期14卷 671-678页

作者： Jun-chun ZHANG Le-ming CHENG Cheng-hang ZHENG zhong-yang luo Ming-jiang NI State Key Laboratory of Clean Energy Utilization Zhejiang University

In this study, a porous inserted regenerative thermal oxidizer （PRTO） system was developed for a 125 kW industrial copper-melting furnace, due to its advantages of low NOr emissions and high radiant efficiency. Zirconium dioxide （ZrOz） ce- ramic foams were placed into the combustion zone of a regenerative thermal oxidizer （RTO）. Different performance characteris- tics of the RTO and PRTO systems, including pressure drop, temperature distribution, emissions, and energy efficiency, were evaluated to study the effects of the porous inserts on non-premixed CH4 combustion. It was found that the PRTO system achieved a significant reduction in the NOx emission level and a fuel saving of approximately 30% compared to the RTO system. It is most suitable for a lean combustion process at an equivalence ratio 〈0.4 with NOx and CO emission levels within 0.002%~）.003% and 0.001%q3.002%, respectively.

关键词： Porous media Regenerative thermal oxidizer (RTO) Non-premixed CH4 combustion

Absorption of NO_2 into Na_2S solution in a stirred tank reactor

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第3期10卷 434-438页

作者： Xiang GAO Rui-tang GUO Hong-lei DING zhong-yang luo Ke-fa CEN State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou 310027 China School of Energy Source and Environmental Engineering Shanghai University of Electric Power Shanghai 200090 China

To understand the absorption mechanism of nitrogen dioxide into a sodium sulfide solution, a stirred tank reactor with a plane gas-liquid interface was used to measure the chemical absorption rate of diluted nitrogen dioxide into sodium sulfide solution. The absorption rates under various experimental conditions were measured and the effects of experimental conditions on nitrogen dioxide absorption rate were discussed. The results show that, in the range of this study, nitrogen dioxide absorption rate increases with increasing sodium sulfide concentration, nitrogen dioxide inlet concentration, and flue gas flow rate, but decreases with increasing reaction temperature and oxygen content in flue gas.

关键词： Nitrogen dioxide Gas-liquid reaction Kinetics Absorption

Experimental study on the spatial distribution of particle rotation in the upper dilute zone of a cold CFB riser

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第7期9卷 922-931页

作者： Xue-cheng WU Qin-hui WANG Chen TIAN zhong-yang luo Meng-xiang FANG Ke-fa CEN State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou 310027 China

Particle rotation plays an important role in gas-solid flows. This paper presents an experimental investigation on the spatial distribution of average rotation speed for glass beads in the upper dilute zone of a cold circulating fluidized bed(CFB) riser. It is shown that in the horizontal direction,the average rotation speed in the near-wall area is larger than that in the center area,while in the vertical direction,it decreases as the height increases. The reason resulting in this distribution is analyzed by considering several factors including particle size,particle shape,particle number density,particle collision behavior,and the surrounding flow field,etc. The effects of CFB operation conditions on the spatial distribution of average rotation speed are also studied. The results show that the increasing superficial gas velocity increases the average rotation speed of particles in the near wall area but takes nearly no effect on that in the center area. The external solids mass flux,however,takes the opposite effect. It is found that the average rotation speeds of particles in both areas are increased as the total amount of bed material increases.

关键词： Particle rotation Gas-solid two-phase flow Circulating fluidized bed (CFB)

Behavior of alkali minerals in oxyfuel co-combustion of biomass and coal at elevated pressure

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2021年第2期22卷 116-129页

作者： Oris CHANSA zhong-yang luo Wen-nan ZHANG Chun-jiang YU The State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou 310027China Department of Chemical Engineering Mid Sweden University85170 SundsvallSweden

Combustion of biomass or coal is known to yield aerosols and condensed alkali minerals that affect boiler heat transfer *** this work,alkali behavior in the pressurized oxyfuel co-combustion of coal and biomass is predicted by thermodynamic and chemical kinetic *** of solid minerals is evaluated by X-ray diffraction(XRD)analysis of ashes from pressure thermogravimetric *** indicate that a rise in pressure affects solid alkali minerals negligibly,but increases their contents in the liquid phase and decreases them in the gas phase,especially below 900℃.Thus,less KCl will condense on the boiler heat transfer surfaces leading to reduced *** the blend ratio of biomass to coal will raise the content of potassium-based minerals but reduce the sodium-based *** alkali-associated slagging in the boiler can be minimized by the synergistic effect of co-combustion of sulphur-rich coal and potassium-rich biomass,forming stable solid K2SO4 at typical fluidized bed combustion *** modelling based on reaction mechanisms shows that oxidation of SO2 to SO3 plays a major role in K2SO4 formation but that the contribution of this oxidation decreases with increase in pressure.

关键词： Oxyfuel co-combustion Equilibrium calculations Chemical kinetic reactions Mineral’s identifications Thermogravimetric combustion

Production of Functional Materials Derived from Regenerated Silk Fibroin by Utilizing 3D Printing and Biomimetic Enzyme-induced Mineralization

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Chinese Journal of Polymer Science 2024年第3期42卷 299-310,I0005页

作者： Ni Chen Fei-Yu luo Gong-Wen yang Jin-Rong Yao Xin Chen Zheng-zhong Shao State Key Laboratory of Molecular Engineering of Polymers Laboratory of Advanced Materials and Department of Macromolecular ScienceFudan UniversityShanghai 200433China

Critical-sized bone defects, commonly encountered in clinical orthopedic surgery, present a significant challenge. One of the promising solutions is to prepare synthetic bone substitute materials with precise structural control, mechanical compatibility, and enhanced osteogenic induction performance, nevertheless the successful preparation of such materials remains difficult. In this study, a two-step technique,integrating an extrusion-based printing process with biomimetic mineralization induced by alkaline phosphatase(ALP), was developed. Initially,a pre-cured hydrogel of regenerated silk fibroin(RSF) with a small quantity of hydroxypropyl cellulose(HPC) and ALP was prepared through heating the mixed aqueous solution. This pre-cured hydrogel demonstrated thixotropic property and could be directly extruded into predetermined structures through a 3D-printer. Subsequently, the 3D-printed RSF-based materials with ALP underwent biomimetic in situ mineralization in calcium glycerophosphate(Ca-GP) mineralizing solution, utilizing the polymer chains of RSF as templates and ALP as a trigger for cleaving phosphate bonds of Ca-GP. The resulting 3D-printed RSF-mineral composites including hydrogel and sponge possessed adjustable compression modulus of megapascal grade and variable hydroxyapatite content, which could be controlled by manipulating the duration of the mineralization ***, these 3D-printed RSF-mineral composites demonstrated non-cytotoxicity towards rat bone marrow mesenchymal stem cells. Therefore, they may hold great potential for applications involving the replacement of tissues characterized by osteoinductivity and intricate structures.

关键词： Silk protein Alkaline phosphatase Extrusion-based printing Biomineralization

Migration and transformation of Pb,Cu,and Zn during co-combustion of high-chlorine-alkaline coal and Si/Al dominated coal

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Journal of Environmental Sciences 2024年第7期141卷 26-39页

作者： Jiangze luo Qiwei yang Jianqiao Wang Boxiong Shen Zhuozhi Wang Qiqi Shi zhong Zhao Chao Huang Jie Xu Tianjin Key Laboratory of Clean Energy and Pollution Control School of Energy and Environmental EngineeringHebei University of TechnologyTianjin 300103China School of Chemical Engineering Hebei University of TechnologyTianjin 300103China

Shaerhu(SEH)coal is abundant in Xinjiang,*** utilization of SEH suffers from severe ash deposition,slagging,and fouling problems due to its high-chlorine-alkaline *** co-combustion of high-alkaline coal and other type coals containing high Si/Al oxides has been proven to be a simple and effective method that will alleviate ash-related problems,but the risk of heavy metals(HMs)contamination in this process is ***,the volatilization rates and chemical speciation of Pb,Cu,and Zn in co-combusting SEH and a high Si/Al oxides coal,i.e.,Yuanbaoshan(YBS)coal were investigated in this *** results showed that the addition of SEH increased the volatilization rates of Pb,Cu,and Zn during the co-combustion at 800℃from 23.70%,23.97%,and 34.98%to 82.31%,30.01%,and 44.03%,respectively,and promoted the extractable state of Cu and *** addition,the interaction between SEH and YBS inhibited the formation of the Pb residue ***-EDS mapping results showed that compared to Zn and Cu,the signal intensity of Pb was extremely weak in regions where some of the Si and Al signal distributions *** DFT results indicated that the O atoms of the metakaolin(Al_(2)O_(3)·2SiO_(2))(001)surface were better bound to the Zn and Cu than Pb atoms after adsorption of the chlorinated *** results contribute to a better understanding of the effects of high-alkaline coal blending combustion on Pb,Cu,and Zn migration and transformation.

关键词： Heavy metals High-chlorine-alkaline coal Coal blending combustion Density functional theory

Study of the pressure transient behavior of directional wells considering the effect of non-uniform flux distribution

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Petroleum Science 2024年第3期21卷 1765-1779页

作者： Yan-zhong Liang Bai-Lu Teng Wan-Jing luo School of Energy Resources China University of Geosciences(Beijing)Beijing100083China

During the production,the fluid in the vicinity of the directional well enters the wellbore with different rates,leading to non-uniform flux distribution along the directional ***,in all existing studies,it is oversimplified to a uniform flux distribution,which can result in inaccurate results for field ***,this paper proposes a semi-analytical model of a directional well based on the assumption of non-uniform flux ***,the direction well is discretized into a carefully chosen series of linear sources,such that the complex well trajectory can be captured and the nonuniform flux distribution along the wellbore can be considered to model the three-dimensional flow *** using the finite difference method,we can obtain the numerical solutions of the transient flow within the *** the aid of Green's function method,we can obtain the analytical solutions of the transient flow from the matrix to the *** complete flow behavior of a directional well is perfectly represented by coupling the above two types of transient ***,on the basis of the proposed model,we conduct a comprehensive analysis of the pressure transient behavior of a directional *** computation results show that the flux variation along the direction well has a significant effect on pressure *** addition,the directional well in an infinite reservoir may exhibit the following flow regimes:wellbore afterflow,transition flow,inclined radial flow,elliptical flow,horizontal linear flow,and horizontal radial *** horizontal linear flow can be observed only if the formation thickness is much smaller than the well ***,a dip region that appears on the pressure derivative curve indicates the three-dimensional flow behavior near the wellbore.

关键词： Directional well Pressure transient behavior Semi-analytical model Non-uniform flux