低密度循环流化床反应器床层截面平均颗粒速度的变化规律

本文在高8m,内径186mm 的循环流化床中采用 FCC 颗粒,利用 TSI 光纤激光多普勒测速仪测定了局部颗粒速度的径向分布,并获得了床层截面平均颗粒速度。实验结果表明:截面平均颗粒速度随操作气速的增大而增大,随固体循环速率的增大而略有减小。由实验数据回归得到了计算本实验条件下低密度速度的经验关联式。论文还从基本流体力学理论出发,在考虑颗粒加速运动的条件下,建立了一维气、固两相流模型,可以用于预测床层截面平均颗粒速度和空隙率的变化规律,模型计算结果和实验数据吻合较好。     

气相法聚乙烯流化床反应器冷凝模式操作工艺

综述了气相法聚乙烯流化床反应器冷凝模式操作工艺方面的最新专利技术动态。阐明了流化床聚合反应器中气液导流器和喷雾器的设计原理和方法，详细分析了操作工艺条件与产品质量和产率之间的关系。还进一步指出茂金属催化剂与冷凝工艺的结合是一条最优的技术路线。     

快速流化床截面平均空隙率轴向分布及其影响因素

根据在直径0.186m、高8m和直径0.14m、高12m两台快速流化床装置的实验结果，并综合文献研究报道，研究了操作气速、颗粒循环速率、颗粒物性、床层直径以及进口、出口结构等因素对床层截面平均空隙率轴向分布的影响。表明一般情况下，快速流化床截面平均空隙率轴向分布的基本形式是上部空隙率高、下部空隙率低的单调指数函数。在特定的床结构条件下，快速流化床截面平均空隙率轴向分布曲线可能发生变异，即在出口结构有强约束作用时，可能呈反C，在入口结构有弱约束作用时，可能呈S型。     

THE RADIAL DISTRIBUTION OF HEAT TRANSFER COEFFICIENT IN FAST FLUIDIZED BED

This paper presents an experimental study on the axial and radial distributions of heat transfer coefficients in a fastfluidized bed operated at ambient temperature.The following formula is recommended to correlate the local heat transfer coefficients in fast fluidized beds:where a,n_1 and n_2 are functions of radial positions.     

液固反应-再生循环流化系统连续合成十二烷基苯

在新型液固循环反应-再生流化系统中研究了十二烷基苯的合成。探讨了反应转化率、表观反应速率常数、催化剂活性因子等随接触及操作时间的变化规律。分析了新工艺中的产物分布。预测了具有工业意义转化率的反应器结构尺寸和操作条件。     

喷射环流三相流化床反应器轴向液速分布的研究

在喷射环流三相流化床反应器中，应用本文所开发的内热式热膜流体速率探头，获得了带有沉降分离区的夹套式环流反应器在不同压力、气量、流量条件下，不同轴向位置的液体速率分布规律。对于本文所述这类反应器，喷射区流体运动速率最大；自喷口向上，速率先是随距离的增大易急骤下降，然后逐渐向一渐近点逼近；当进入环隙转折口处时，由于气体的逸出及流道的变化液速急骤下降；凝固相进入环隙时，液速随距离的变化也存在渐近点。当采用变径结构时，流道面积突变处的液速变化率仅次于喷射入口区。在环流反应器中，液速主要取决于喷射动能及气提推动力，受液体进料量及压力的影响较小。     

THE PARTICLE VELOCITY DISTRIBUTION IN A RISER OF DILUTE CIRCULATING FLUIDIZED BED

This paper presents an experimental study on the radial and axial profiles of local particle velocity of flu-idized catalyst(FCC)particles in a circulating fluidized bed of 8000mm in height and 186mm in inside diameterwith a Fiber-Optic Probe Laser Doppler Velocimetry.It has been found that the radial profiles of local particlevelocity are parabolic,even in the centre region and steep in the region near the bed wall,and that the length ofparticle acceleration along the bed height is longer than expected.The following formula has been recommended to correlate the 1 ocal particle velocity with dilute gas-solidflow in the bed:where a,b,c and e are functions of radial positions.     

双射流流化床空隙率的分布

在 ３００ ｍｉｎ×５０ ｍｉｎ×２６００ ｍｍ的二维射流床中,采用内径为 １１ ｍｍ的对称双射流管,研究了等速射流条件下射流管间距、喷口射流气速、静床高度对床层空隙率分布的影响,发现射流管间距、喷口射流气速是双射流产生射流区合并的主要原因;并得到了具体实验条件下空隙率分布的数据．同时研究了双射流管不等速射流条件下空隙率分布的规律．     

DESIGN AND APPLICATION OF FLUIDIZED BED PHOTOCATALYTIC REACTOR

Ｐｈｏｔｏｃａｔａｌｙｔｉｃｄｅｇｒａｄａｔｉｏｎｏｆｏｒｇａｎｉｃｐｏｌｌｕｔａｎｔｉｓａｎｅｗａｎｄｐｏｔｅｎｔｉａｌｍｅｔｈｏｄｔｏｔｒａｎｓｆｏｒｍｉｔｔｏｈａｒｍｌｅｓｓｉｎｏｒｇａｎｉｃｍａｔｅｒｉａｌ,ｓｕｃｈａｓＣＯ2 ａｎｄＨ2 Ｏ .Ｓｏｆａｒ ,ｍｏｓｔｏｆｐｈｏｔｏｃａｔａｌｙｔｉｃｒｅａｃｔｏｒｓｗｅｒｅｃｙｌｉｎｄｅｒｏｒｔａｂｕｌａｔｅｐｈｏｔｏｒｅａｃｔｏｒ.ＴｈｅｒｅｌｅｖａｎｔｐｈｏｔｏｃａｔａｌｙｓｔｗａｓＴｉＯ2ｎａｎｏｍｅｔｅｒｐｏｗｄｅｒ .Ａｌｔｈｏｕｇｈａｆｅ…     

DESIGN AND APPLICATION OF FLUIDIZED BED PHOTOCATALYTIC REACTOR

Photocatalytic degradation of organic pollutant is a new and potential method to transform it to harmless inorganic material, such as CO2 and H2O. So far, most of photocatalytic reactors were cylinder or tabulate photoreactor. The relevant photocatalyst was TiO2 nanometer powder. Although a few investigators had aimed their research field to fluidized bed reactor, their reaction systems were of biphase, such as solid-liquid or solid-gas. Few people focused their research on the triphasic fluidized bed photocatalytic reactor［1］. Compared with traditional photoreactors, a triphasic fluidized bed photoreactor has more advantages［2］: (1) The solid photocatalyst can be separated easily. (2) Its configuration meets the requirement of higher surface area-to-volume ratio of photocatalytic, which is much lower in a fixed bed or a plate photoreactor. (3) The UV light can be used more efficiently. (4) The mass transfer conditions can be controlled and improved easily. (5) It suited to pilot-scale or large-scale operations. For the UV light penetration and photon efficiency should be considered, the photocatalytic reactor differed greatly from a typical fluidized bed reactor.     

流化床反应器气固传热面积模型

研究了流化床反应器内发生气固反应时间的传热机理,认为气固间的传热面积包括两部分,即气泡内所含颗粒的表面积与一气泡和泡晕间的有效传热面积 ,据此首次导出了气固传热面积模型A＝u0-umf/22.26db0.5-umf[4.5unf ρgCpg/db 5.85(λgρgCpg)0.5g^0.25/db^1.25]LmS/a将该模型 应用于半间歇的裂化催化剂烧炭再生过程,与实验数据的比较表明,模型预测是可靠的。     

生物质的流化床转化

综述了生物质的流态化特性及生物质的流化床利用,内容包括：生物质在流化床中燃烧,气化以及在流经床中的热解,并介绍了煤与生物质共气化燃烧的最新进展。     

THE ESTIMATION OF THE DENSE PHASE VOIDAGE OF A GAS FLUIDIZED BED

Dense phase voidage can be estimated by cutting gas flow and following the rate of bed collapse. Abrupt cessation of flow is not possible when excess gas in the windbox can only discharge through the bed. The magnitude of this problem is examined experimentally.     

气液固三相磁稳定流化床的操作状态对反应结果的影响

以氮气、水、铁粉为气液固三相研究了三相磁稳定流化床的床层操作状态；以重整生成油的烯烃饱和加氢过程为体系，研究了铁粉与大比表面非晶态合金催化剂混合颗粒为固相的磁稳定流化床中床层操作状态对反应结果的影响。找到了有利于气液固三相反应的磁稳定流化床床层操作状态     

A SIMPLE METHOD FOR STUDYING THE KINETICS OF GAS-SOLID REACTIONS IN A FLUIDIZED BED REACTOR

A methodology for studying the kinetics of gas-solid reactions in a fluidized bed reactor is presented. This procedure is based on the analysis of the response of the system (flue gases) when batches of solids of different weight are added to the reactor. The method has been applied to the study of limestone particle calcination. The calcination rate constants obtained are in good agreement with those found in the literature. The method offers the advantage of simplicity and avoids the use of model assumptions or empirical correlations.     

INVESTIGATIONS OF THE BUBBLE PHASE BEHAVIOR IN A HIGH TEMPERATURE FLUIDIZED BED REACTOR WITH COALCOMBUSTION

The properties of bubbles in a bench-scale fluidized bed reactor, 30 cm in diameter, during coal combustion were determined by means of a newly developed cooled bubble probe and a data processing system at temperatures up to 850°C and fluidization indexes up to 10 in axial and radial positions in the bed. The fluidization index above 4 and the temperature have only slight effect on the bubble properties. Their variation along the height above the gas distributor is dominant.

Oxygen and Co₂-concentration profiles were measured in the bed and in the freeboard, and the o₂-profiles were calculated by means of measured bubble data and bubble models. A comparison of measured and calculated o₂-profiles indicates that the mass transfer rates between the emulsion and bubble phases are larger than the ones calculated by the models.     

吸附床内气体浓度分布的测定

<正>1引言固定床内流体的轴向与径向混合作用对床层内的传质、传热和反应过程有很大的影响,研究固定床内流体的混合特性一直受到各国学者的重视。固定床中流体与固体颗粒间的传质与流体的混合作用是相互影响的。一些学者对吸附床中气体澎合特性进行了研究。l－3。,但他们所使用的固定床实验装置内径比较小（100mm以下）,一般都采用改变床层高度,在床层出口端收集气体样品进行分析,测定不同床层截面上气体浓度分布。这一检测气体浓度的方法对气、固间有较大传质速率的吸附床会产生较大的误差。为准确测定床层内气体浓度及变化,建立了气体浓度微机检测系统和内径为267nlm的气相吸附装置,催化燃烧式气体浓度传感器置于床层内,可连续检测和记录床层内历点浓度。应用该装置测定了甲烷－空气－SA分子筛物系在床层内不同横截面上甲烷浓度分布及随时间变化的数据。     

EFFECTS OF PARTICLE CHARACTERISTICS ON THE PERFORMANCE OF A FAST FLUIDIZED BED REACTOR

A heterogeneous model for the fast fluidized bed reactor which carries out a gas-solid non catalytic reaction is presented. The hydrodynamics of the fast fluidized bed is characterized by the model of Kwauk et al. (1985) which assumes the existence of two phases; a dense phase and a dilute pneumatic transport phase. For a given solid flowrate, the length of the reactor occupied by each phase depends on gas velocity, particle diameter and density and average voidage within the reactor. The gas-solid reaction is assumed to follow the shrinking core model. The solids are assumed to be completely backmixed in the dense phase and move in plug How in the dilute pneumatic transport phase. The gas phase is assumed to be in plug flow in both phases

For given gas and solid flowrates, the transition from the dense phase flow to the fast fluidized bed (containing two regions) as functions of particle size and density is determined using the model of Kwauk et al. (1985). The numerical solution of the governing mass balance equations show that for given solid and gas flowrates, (and average voidage) the gas phase conversion shows an unusual behavior with respect to particle diameter and density. Such behavior is resulted from the effects of particle diameter and density on the reactor volume occupied by each phase and the effect of particle diameter on the apparent reaction rate. The numerical results show that a fast fluidized bed gives the best conversion at large particle density and for the particle diameter which results the fast fluidized bed to be operated near the pure dense phase flow.     

厌氧流化床生物膜形成及稳定性的研究

在自行设计的厌氧流化床反应器上地厌氧流化床生物膜的形成及其稳定性进行了研究，考察了影响反应器内生物滞留量的因素（接种污泥，温度，ｐＨ，基质特性，有机质负荷）和影响生物膜构成的因素（微生物的品种及性质，生物化学反应，载体，水力特性）简述了生物膜的形成机理。     

厌氧流化床处理硫酸盐草浆废水的研究

本文研究了ＡＦＢ反应器在中温（３０±２）℃条件下处理硫酸盐草浆废水的性能，其达到的指标为：当进水ＣＯＤ浓度２０００～５０００ｍｇ／Ｌ，水力停留时间３～９ｈ，ＣＯＤ去除率为５０．１％～７０．２％，容积产气率１．４６～２．０ｍ３／ｍ３·ｄ，有机容积负荷达４３．２ｋｇＣＯＤ／ｍ３·ｄ；并初步研究了废水中ＳＯ２－４、Ｓ２－等物质对厌氧生物的抑制作用，提出了消除其影响的方法。