粉体消石灰在双层滤料床中烟气脱硫试验

在模型试验台上进行了消石灰粉体在双层滤料床中的脱硫试验.研究了床温、SO2浓度、吸附剂有效钙含量、吸附剂加入量等多种因素对消石灰粉体在双层滤料床中的脱硫影响.结果表明：床温影响最为显著,床层脱硫穿透时间随温度升高而明显增加,床温400℃时,穿透时间为17min,温度600℃时,穿透时间为25min.床温400℃时,消石灰粉体在双层滤料床中重复吸附8次,钙利用率为30%-32%,为提高钙利用率,尚需进一步提高床温.     

A Novel Production Route for Nylon-6:. Aspects of Catalysis and Process Development

Summary: A novel production route for nylon-6 out of 6-aminocapronitrile has been investigated. Hydrolysis of 6-aminocapronitrile using a solid porous ZrO₂ catalyst is the key step in this novel route. Nylon-6 with a number average molecular weight of 10 · 10³ g · mol⁻¹ can be produced from the hydrolyzed 6-aminocapronitrile. The reactor set up for the polycondensation can in broad outline be the same as the continuously operated reactor used for the ε-caprolactam based production of nylon-6. For the hydrolysis of 6-aminocapronitrile a number of parallel batchwise operated loop reactors is recommended. A fixed bed of catalyst particles is part of each recirculation loop. Intraparticle mass transport limitation can be avoided by using catalyst particles made of a shell of active ZrO₂ and a massive inert core. An annual production of 50 · 10⁶ kg nylon-6 demands for 5.3 m³ zirconia.     

纳米硫化锌的制备及光谱分析

采用超重力反应结晶法制备了纳米硫化锌粒子,并通过透射电子显微镜(TEM)、X射线粉末衍射仪(XRD)、X射线光电子能谱仪(XPS)、傅里叶红外光谱仪(FTIR)、紫外-可见光分光光度计(UV-Vis)和X射线能谱仪(EDX)对纳米硫化锌的形貌、结构、组成和光谱性能进行了细致分析。结果表明：超重力反应结晶法制备的纳米硫化锌粒子为球形,平均粒径为42 nm;XRD图谱表明纳米硫化锌呈现较好的闪锌矿晶型; XPS能谱表明纳米硫化锌的S(2p)的电子结合能为162.6 eV,Zn的2p_3/2,2p_1/2的电子结合能分别为1021.4, 1044.6eV。红外光谱研究表明纳米硫化锌在400～4 000cm-1范围内具有良好的红外透过率。紫外-可见光谱研究发现纳米硫化锌在200～340nm的紫外区域有较强的吸收,其禁带宽度为3.57eV。EDX能谱表明该法制备的纳米硫化锌具有较高的纯度。     

非驻定过滤燃烧的均相模拟

基于一维层流反应流模型,构建了新的准稳态均相模型,并对堆积床内充分发展后的低速过滤贫燃过程进行数值模拟.将计算结果与传统双相模型进行比较,分析弥散效应和化学反应机理等对计算结果的影响,并开展输运项分析;将均相模型的数值结果与准稳态和瞬态的理论结果进行比较,验证理论方法.     

不同惰性填料复极性固定床电解槽处理对硝基酚钠废水行为比较

分别以磺化煤、果壳、PVC塑料、回收旧塑料等4种密度与活性炭相当的惰性填料替代工程上广泛使用的石英砂,结合适当的反冲洗解决复极性固定床电解槽(BPBC,b ipolar packed bed cell)存在的电极污染及填料分层问题.并以含有对硝基酚钠的废水降解实验考察其应用的可行性.结果表明,以回收旧塑料及磺化煤作为填料的BPBC处理效果优于石英砂的,而果壳、PVC塑料的与石英砂的处理效果相当.反冲洗后,以磺化煤、果壳、PVC塑料和回收旧塑料作填料的电解槽再生率均大于石英砂的.     

Euler-Lagrange/DEM simulation of wood gasification in a bubbling fluidized bed reactor

We present an Euler–Lagrange method for the simulation of wood gasification in a bubbling fluidized bed. The gas phase is modeled as a continuum using the 2D Navier–Stokes equations and the solid phase is modeled by a Discrete Element Method(DEM)using a soft-sphere approach for the particle collision dynamic. Turbulence is included via a Large-Eddy approach using the Smagorinsky sub-grid model.The model takes into account detailed gas phase chemistry,zero-dimensional modeling of the pyrolysis and gasification of each individual particle,particle shrinkage,and heat and mass transfer between the gas phase and the particulate phase.We investigate the influence of wood feeding rate and compare exhaust gas compositions and temperature results obtained with the model against experimental data of a laboratory scale bubbling fluidized bed reactor.     

Drag models for simulating gas–solid flow in the turbulent fluidization of FCC particles

This paper examines the suitability of various drag models for predicting the hydrodynamics of the turbulent fluidization of FCC particles on the Fluent V6.2 platform. The drag models included those of Syamlal–O’Brien, Gidaspow, modified Syamlal–O’Brien, and McKeen. Comparison between experimental data and simulated results showed that the Syamlal–O’Brien, Gidaspow, and modified Syamlal–O’Brien drag models highly overestimated gas–solid momentum exchange and could not predict the formation of dense phase in the fluidized bed, while the McKeen drag model could not capture the dilute characteristics due to underestimation of drag force. The standard Gidaspow drag model was then modified by adopting the effective particle cluster diameter to account for particle clusters, which was, however, proved inapplicable for FCC particle turbulent fluidization. A four-zone drag model (dense phase, sub-dense phase, sub-dilute phase and dilute phase) was finally proposed to calculate the gas–solid exchange coefficient in the turbulent fluidization of FCC particles, and was validated by satisfactory agreement between prediction and experiment.     

Experimental investigation on flow asymmetry in solid entrance region of a square circulating fluidized bed

To study the influence of back feeding particles on gas-solid flow in the riser, this paper investigated the flow asymmetry in the solid entrance region of a fluidized bed by particle concentration/velocity measurements in a cold square circulating fluidized beds （CFB）. The pressure drop distribution along the riser and the saturation carrying capacity of gas for Geldart-B type particles were first analyzed. Under the condition of u0 = 4 m/s and Gs = 21 kg/（m^2 s）, the back feeding particles were found to penetrate the lean gas-solid flow near the entrance （rear） wall before reaching the opposite （front） wall, thus leading to a relatively denser region near the front wall in the bottom bed. Higher solid circulation rate （u0 =4 m/s, Gs = 33 kg/（m^2 s）） resulted in a higher particle concentration in the riser. However the back feeding particles with higher momentum increased the asymmetry of the particle concentration/velocity profile in the solid entrance region. Lower air velocity （u0 =3.2 m/s） and Gs =21 kg/（m2 s）, beyond the saturation carrying capacity of gas, induced an S-shaped axial solid distribution with a denser bottom zone. This limited the penetration of the back feeding particles and forced the flnidizing air to flow in the central region, thus leading to a higher solid holdup near the rear wall. Under the conditions of uo = 4 m/s and Gs = 21 kg/（m^2 s）, addition of coarse particles （dp= 1145 μm） into the bed made the radial distribution of solids more symmetrical.     

流化床条件下煤的一次爆裂特性的实验研究

流化床锅炉中煤的爆裂特性对锅炉运行的炉内传热、碳转化率和细微颗粒的排放等许多方面有重要影响。本文在一台小型常压流化床反应器中研究了了种烟煤的一次爆裂烟煤的。对此烟煤不同宏观煤岩类型（亮煤和暗煤）的一次爆裂特性进行了比较研究。实验发现颗粒的一次爆裂率和爆裂程度很大程度上取决于颗粒粒径以及煤颗粒的组成,亮煤具有与暗煤不同的一次爆裂特性,同一粒径的煤颗粒爆裂后形成具有一定特点的粒径分布。针对不同煤岩类型     

Design and performance of a fibrous bed bioreactor for odor treatment

Biological processes have become popular for odor treatment. In this study, a novel fibrous bed bioreactor was applied for treatment of odorous gas. The column reactor was packed with spirally wound fibrous sheet material on which a consortium of microorganisms selected from activated sludge was immobilized. The first stage of this work comprised a preliminary study that aimed at investigating the feasibility of the fibrous bed bioreactor for treatment of odorous volatile fatty acids (VFAs). In this stage, the performance of a fibrous bed bioreactor at increasing mass loadings ranging from 9.7 to 104.2 g/(m³·h) was studied. VFA removal efficiencies above 90% were achieved at mass loadings up to 50.3 g/(m³·h). At a mass loading of 104.2 g/(m³·h), removal efficiency was found to be 87.7%. In the second stage of the work, the process was scaled up with design and operational considerations, namely, packing medium, process condition, and configuration selections. A trickling biofilter with synthetic fibrous packing medium was selected. It was operated under countercurrent flow of gas and liquid streams. The effects of inlet concentration and empty bed retention time on bioreactor performance were studied. The bioreactor was effective in treating odorous VFAs at mass loadings up to 32g/(m³·h), at which VFAs started to accumulate in the recirculation liquid, indicating that the biofilm was unable to degradeall the VFAs introduced. Although VFAs accumulated in the liquid phase, the removal efficency remained above 99%, implying that the biochemical reaction rate, rather than gas-to-liquid mass transfer rate, was the limiting factor of this process. The bioreactor was stable for longterm operation; no clogging and degeneration of the packing medium was observed during the 4-mo operation.