卧式双轴搅拌床反应器混合特性研究

本文对卧式双轴气相聚合搅拌床反应器的混合特性进行了实验研究。以三氧化二铝粉体和氯化钾粉体分别为主体物料和示踪物料,用电导法考察了搅拌转速、器内物料的装料高度及通气速率对该搅拌床反应器的混合特性的影响并获得了相应的关联式。结果表明,弗鲁德数、无因次装料高度及通气速率对混合特性有明显的影响。     

麦秸快速热解的试验研究

介绍了喷动流化床(喷动床)快速热解试验装置及方法,研究了主要影响因素———热解温度对麦秸热解气、液、固三种产品的产率和热解气成分的影响,采用色-质谱联用仪(GC-MS)分析了热解液成分。结果表明,热解温度为460~520℃时热解油产率最大,主要有醋酸、羟基乙醛、羟基丙酮、左旋葡聚糖、糠醛,油热值为17.0MJ.kg-1;热解气主要为CO2和CO,还含有少量H2、CH4和C2~C4的烯烃。     

搅拌釜中自浮颗粒三相体系的混合时间

液相混合时间是搅拌过程中的重要内容。在釜径３８６ｍｍ的搅拌釜内,采用热电偶温差法考察了搅拌桨型、挡板、等操作因素对自浮颗粒三相搅拌混合的液相混合时间的影响。     

Influence of Operating Conditions for Fast Pyrolysis and Pyrolysis Oil Production in a Conical Spouted‐Bed Reactor

Fast pyrolysis experiments of larch sawdust were conducted in a conical spouted‐bed reactor to study the influences of reaction temperature, inlet gas velocity, feeding rate, and particle size on the product yield and pyrolysis oil quality. For the first time, the optimal conditions were determined for various pyrolysis operations of such reactor to increase the yield and quality of pyrolysis oil. The results demonstrate that the biomass particle size, reaction temperature, biomass feeding rate, and inlet gas velocity all affected the quality and yield of the pyrolysis oil, in this order.     

Positron Emission Particle Tracking for Liquid-Solid Mixing in Stirred Tanks

Mixing in stirred tanks is vital to a wide range of industrial processes, typically requiring solids to be fully suspended and evenly distributed. The quality of suspension and mixing is typically measured visually. Such measurements are thus subject to human interpretation and can only feasibly be conducted in transparent systems – an uncommon condition in industrial systems. Visual measurements of homogeneity must also infer full 3D distributions of particles solely from the observation of a limited section thereof. This work details methods by which a system's homogeneity and state of suspension may be measured and quantified with no human interpretation, which can extract information from opaque systems and consider full 3D data acquired throughout the interior of a given system.     

Particle Separation in Moving Bed Biofilm Reactor: Applications and Opportunities

Different solid/liquid separation techniques for particle separation after a moving bed biofilm reactor are discussed. Conventional technologies such as sedimentation, floatation, and depth filtration are reviewed based on reports and articles in the literature. Optimal operating parameters that lead to satisfactory solids removal rates were given for each technology. Disc and membrane filtration are also discussed as relatively new technologies that offer advanced solids separation process. The potential of membrane separation, especially submerged membrane reactors (sMBR), were found and they are therefore proposed as a good alternative to conventional solid/liquid separation technologies. The nature and characteristics of the biofilm process also opens for a variety of possible configurations of submerged MBR that could be employed for advanced treatment of effluent from a moving bed biofilm process.     

生物质热解反应装置研究现状及展望

生物质热解是实现生物质能源化利用的重要途径,对解决日益严重的能源问题有着重要意义。着重介绍了几种典型的生物质热解反应器的研究现状,并列举了近期开发出的几种新型热解反应装置,总结了不同种类的热解反应器的工作原理及各自优缺点和适用情况。对催化热解和生物质原料预处理及反应器进行了综述,指出开发新型高效、高活性热解催化剂和加大对原料预处理技术的基础理论探索力度是未来生物质热解研究的发展方向。     

The Use of Positron Emission Particle Tracking in the Study of Multiphase Stirred Tank Reactor Hydrodynamics

This paper describes the use of positron emission particle Tracking (PEPT) in the analysis of local particle and fluid velocities in solid‐liquid stirred tank reactors agitated with a Rushton turbine and an upward‐pumping pitched blade turbine. PEPT captures the full three‐dimensional characteristics of hydrodynamics and mixing in stirred vessels, allowing the analysis of the two‐phase flow fields. Furthermore, by comparing the liquid and particle velocities, the spatial and temporal variation of the relative particle‐liquid velocity can be estimated. Such information reveals considerable heterogeneity in the vessel and facilitates the evaluation of impeller design, particularly with the aim of minimizing mass transfer limitations.     

喷动-载流床中粒径对内蒙霍林河褐煤快速热解产物的影响

在喷动–载流床内对霍林河褐煤进行了快速热解，考察了0.125~0.28 mm范围内煤粉颗粒粒径对煤热解总失重、热解产物产率以及气体和液体产物具体组成的影响. 气体和液体产物的组成分别利用气相色谱和色质联用仪分析. 实验表明, 随颗粒粒径增大，煤中挥发份脱出率略有降低，半焦产率略有升高，气体总产率增大，CH4，无机气体，C2H6，C3H8等呈现上升趋势. 而随颗粒粒径增大，液体产率降低，其中沥青质的降低较为显著. 正己烷可溶物产率随颗粒粒径增加有少许降低. 热解水产率随着颗粒粒径的增大而增加. 颗粒粒径对正己烷可溶物中的各类组份的含量也有一定的影响.     

Pyrolysis of Softwood Carbohydrates in a Fluidized Bed Reactor

In the present work pyrolysis of pure pine wood and softwood carbohydrates, namely cellulose and galactoglucomannan (the major hemicellulose in coniferous wood), was conducted in a batch mode operated fluidized bed reactor. Temperature ramping (5 °C/min) was applied to the heating until a reactor temperature of 460 °C was reached. Thereafter the temperature was kept until the release of non-condensable gases stopped. The different raw materials gave significantly different bio-oils. Levoglucosan was the dominant product in the cellulose pyrolysis oil. Acetic acid was found in the highest concentrations in both the galactoglucomannan and in the pine wood pyrolysis oils. Acetic acid is most likely formed by removal of O-acetyl groups from mannose units present in GGM structure.     

不同粒度分布高硫焦颗粒在强混燃烧器内的流动特性

利用一套新型强混燃烧器,对3种不同粒度分布的高硫焦颗粒的流动特性进行了较为详尽的考察. 反应器主要由预混段和提升段组成,两部分结构尺寸分别为f240 mm′3000 mm和f70 mm′9000 mm. 实验操作条件为：提升管表观气速8~18 m/s,颗粒循环速率60~200 kg/(m2×s). 通过对3种不同粒度分布的颗粒在强混燃烧器内颗粒固含率、颗粒速度轴径向分布的测定,发现随掺入细颗粒比例的增加,截面平均颗粒速度降低;在较粗的高硫焦颗粒中适当掺入细粉,可使床层内颗粒固含率增加,返混加剧,停留时间延长,有利于高硫焦的充分燃烧.     

The Operating Performance of Stirred Column Reactor

A theoretical analysis of the effects of flow and mixing on the operating features of astirred column reactor(SCR)with multistage mixers and cooling partition plates was conducted.Amethod for calculating the concentration reduction for a second order chemical reaction in a SCRwas proposed.The reactants concerned were pre-mixed before feeding into the SCR.The SCR wascomposed of a number of stages with interstage backmixing.Experimental investigation with variousreaction media were carried out in order to study the effect of mixing on the operational performanceof the SCR.The experimental data were compared with the theoretical results.     

Experimental Study on Hydrogenation of SiCl_4 to SiHCl_3 in a Stirred Bed Reactor

The hydrogenation of SiCl_4 to SiHCl_3 was studied in a stirred bed reactor with CuCl catalyst.The properties of the CuCl catalysts and silicon particles before and after the reaction were characterized by SEM,XRD and XPS.The XRD showed that the active component of Cu3Si was formed during the reaction,and the EDX proved the molar ratio of Cu and Si on the region of apertures.The valent of Cu was discussed by XPS before and after the hydrogen reaction.Then the effects of the reaction temperature,pressure,molar ratio of H2 to SiC l4,weight hourly space velocity(WHSV),and catalyst loading were studied.The results showed that the conversion rate of Si Cl4 was about 38%at WHSV of 190 Nm3/(t·h),temperature of 540℃,pressure of 1.8 MPa,catalyst loading of 0.9%(ω),and molar ratio of H2 to Si Cl4 1.7:1.Based on the experemental results,a reaction mechanism was proposed,which involved the continuous consumption of silicon(many apertures was showed on SEM image)and formation of new Cu3Si active component during the hydrogenation reaction.     

搅拌鼓泡塔的实验模拟研究

利用CFD软件对搅拌鼓泡反应器内4种不同表观气速下的内部流场的流体力学行为进行了模拟。并对其计算结果进行了分析。研究发现:气速为2 m/s时反应器的流体特性效果比其它气速情况下的结果来说较佳。由于导流筒的作用,流体沿器壁向上和向下都具有对称的旋流,漩涡中心处出现了滞留区域没有速度。     

Coal Gasification in Moving Bed Reactor with a Draft Tube

1 INTRODUCTIONMany different types of reactors,for example,fixed bed,moving bed,fluidized bed and spoutedbed,have been used in industrial production and laboratory in research studies.Althougheach of these coal gasifiers has its own specific advantages,there exists,generally speaking,certainwaste gas in product gas because of the direct burning of coal with oxygen or air to provide heatneeded in the endothermic process of coal gasification in gasifiers.A new type of moving bed     

垂直立管中颗粒移动床蠕动流动特性的实验研究

在无负压差的环境下,采用PV6D型颗粒速度测量仪,考察了垂直立管中FCC催化剂颗粒移动床的蠕动流动特性. 结果表明,颗粒质量流率较小时立管中颗粒流动具有明显的蠕动流动特性,可划分为两种流态,拟气固雷诺数Re<500时为间歇式蠕动流动,5004000时颗粒的蠕动流动转变为密相流化流动. 立管中颗粒的蠕动流动主要是出口区颗粒成拱与崩塌交替进行产生的,其次为颗粒与器壁滑动摩擦力的不稳定性变化起作用. 微观上颗粒流动的蠕动行为是颗粒之间力链作用变化的结果.     

固定床热解紫茎泽兰茎干的研究

考察了热解温度、停留时间、粒径、升温速率等因素对紫茎泽兰茎干在固定床内热解燃气特性的影响。结果表明,H₂含量随着热解温度的升高、停留时间的延长、粒径的减小、升温速率的下降而上升,最高可达70%左右,远高于目前几种生物质热解所产生的H₂量; CO含量随着热解温度的升高而升高,本实验条件下其他因素对它的影响不大; CH₄含量随着热解温度的升高、停留时间的延长、升温速率的下降而下降。燃气热值在10000～13500 kJ/m³左右,属于中热值燃气,随着热解温度的上升、停留时间的延长、粒径的增大而下降,随升温速率的增加先上升后下降。     

无序环流混合器的流体力学特性和颗粒混合特性

在内径为Φ286 mm的无序环流混合器装置中,研究了无序环流混合器的流体力学特性和颗粒混合特性。以催化裂化(FCC)平衡剂为颗粒相,在中心区表观气速为0.3~0.5 m/s,边壁区表观气速为0.1 m/s,系统循环强度为0.25~1.00 kg/s的操作条件下,采用PV-6D型颗粒速度密度测量仪测量了混合器内床层各截面密度,并给出不同操作条件下的截面不均匀指数(RNI);采用热颗粒示踪技术给出了混合器内各测量截面的无因次温度分布,并引入混合指数用来定量描述不同操作条件下的颗粒混合程度,同时对比了传统环流混合器与无序环流混合器的混合能力。结果表明,无序环流混合器内部床层密度呈现中心低,边壁高的分布模式。随着循环强度的增加,RNI先减小后增大,随着表观气速的增加,RNI增大。预混合区混合指数为0.7~0.9,在高循环量,低中心区表观气速条件下(G_s为1.00 kg/s,u_(gd)为0.3 m/s),下料管进料影响区的截面混合指数低于其他操作条件。另外,无序环流混合器混合能力优于传统环流混合器。     

外循环撞击流反应器混和时间实验研究

在容积为160L的冷模装置上,以水为介质、KCl水溶液为示踪剂,测定了外循环撞击流反应器（ECISR）的混和时间,采用正交试验法和单因素试验法考察了撞击段结构、进料位置、循环位置、循环流量对ECISR混和时间的影响。结果表明：实验范围内,循环位置对混和时间影响最大,进料位置次之,循环流量越大混和时间越短,撞击段结构Ⅰ的混和时间略低于结构Ⅱ。     

床层与颗粒直径比小的固定床反应器径向空隙率分布

采用旋转法测定了床径比小的固定床反应器中的径向空隙率分布。填充颗粒为球形、圆柱形。填充形式为紧密填充。通过对实际数据的拟合建立了描述其径向空隙率分布的数学模型。