3万t/a苯胺流化床反应器的设计

介绍了3万t/a苯胺流化床反应器整体结构,重点介绍了设备直径、高度的确定,内构件设计和分离段旋风分离器的设计,此设备已成功应用到生产中并稳定运行多年。     

高速气固流化床局部瞬态行为混沌分析

在内径 1 86mm、高 9m的提升管中 ,通过改变操作气速获得湍动流化床、快速流化床和稀相输送典型的操作状态 ,使用光纤密度探头在轴向不同截面的不同径向位置处测得密度脉动时间序列 ,以反映不同流型下 ,不同浓、稀相区的瞬态动力学行为 .利用确定性混沌理论分析了局部密度脉动信息 ,以Kolmogorov熵定量地表征系统的动力学特征 .实验结果表明 ,Kolmogorov熵随流型的变化能正确地反映相应流型的特点 ,可用来描述不同流型下的流动结构 .在忽略壁面附近行为的条件下 ,对 3种流型、不同的浓稀相区 ,局部熵值随局部固含率变化可分为两个区 :当局部固含率高于 0 0 5时 ,熵几乎不随局部固含率的变化而变化 ;当局部固含率低于 0 0 5时 ,熵随局部固含率的减小而急剧增大 .这说明系统的混沌特征与局部固含率关系密切 ,局部固含率对系统局部动态行为起控制作用 .     

大颗粒尿素技术与工艺流程比较

阐述了大颗粒尿素的特点及当今世界上生产大颗粒尿素的主要造粒工艺,对海德鲁、东洋工程公司造粒工艺与双转鼓流化工艺大颗粒尿素技术进行了比较,对大颗粒尿素的前景进行了展望。     

离心流化床初始流化状态的研究(Ⅰ)基本理论

通过简化求解离心流化床连续介质模型基本控制方程,获得了初始流化速度、压力、空隙率、空隙气速、床层膨胀和床层压降的计算方程式。理论预报的临界流化速度和床层压降与实验结果吻合得很好。揭示了离心流化床随流速增大由表面逐层初始流化;流化后各半径处流化程度不同。理论分析还表明气体压缩性的影响随着床体转速的增大而增大。     

大颗粒尿素技术与工艺流程比较

阐述了大颗粒尿素的特点及当今世界上生产大颗粒尿素的主要造粒工艺,对海德鲁、东洋工程公司造粒工艺与双转鼓流化工艺大颗粒尿素技术进行了比较,对大颗粒尿素的前景进行了展望。     

Mixing and combustion in a shallow coal-limestone fluidized bed combustor

A model based on the Monte Carlo approach was developed to simulate the mixing and combustion behavior of a shallow coal-limestone fluidized bed combustor. The model involved the coupling of two sub-models: a combustion sub-model based on the two-phase concept of fluidization and a mixing sub-model based on our previously developed dynamic mixing model. The combustion sub-model considered both the volatile and char combustion. It assumed that the combustor consisted of three distinct phases, i.e., jet, bubble and emulsion, with combustion occurring only in the emulsion phase. The mixing sub-model considered the upward or downward movement of a coal particle in the bed as being governed by certain probability laws; these laws were, in turn, affected by the bubbling hydrodynamics. In all, the combustor simulation model took into consideration the effects of coal feed rate, coal size distribution, limestone size, air flow rate and combustor temperature on the combustor behavior. The simulation results included the dynamic response of coal concentration profile, coal size distribution, coal particle elutriation rate as well as the mixing status between the coal and limestone particles.     

离心流化床初始流化状态的研究(Ⅱ)实验研究

对离心流化床初始流化状态进行了实验研究。结果表明,下行程床层压降流速曲线的规律一致,流化时床层压降趋于稳定;上行程曲线受床体结构、物料装填方式和运行状况的影响很大。实验测定初始流化速度应采用下行程曲线。可视性实验证实了离心流化床逐层初始流化,已流化部分的床层物料充分混合。     

气固固循环流化床密相床层压力脉动研究

在不同实验条件下研究了气固固循环流化床密相床层的压力脉动。压力脉动的情况表明：细颗粒的循环及循环量对粗颗粒的流体力学行为有很大影响。气速越低,影响程度越大。     

韶钢热电厂140 t/h流化床锅炉点火启动技术分析

初步分析了韶钢热电厂140t/h鼓泡流化床锅炉焦炉煤气床上整床点火失败的情况，详细介绍了木炭分床点火的成功方法。     

Studies on the effects of various design and operational parameters on solid circulation rate in a recirculating fluidized bed

Effects of various operational parameters, such as draft tube superficial air velocity and solid inventory and design parameters such as jet diameter and clearance between perforated plate and draft tube bottom on the solid circulation rate of a recirculating fluidized bed are studied. A simple butterfly valve arrangement was used for the direct measurement of the solid circulation rate.     

设有内置高温组合式旋涡分离器的循环流化床锅炉

开发了一种新型内置组合式高温旋涡分离器,其阻力低、体积小、耐磨损、结构简单、安装方便、材质要求低、烟气处理量大、性能稳定、且可按锅炉容量变化随意组合,易于大型化,尤其是具有分离、燃烧、燃烬的多重功能,可同时降低固体燃料的机械不完全燃烧损失与化学不完全燃烧损失,可满足不同容量循环流化床锅炉的要求。内置组合式高温旋涡分离器用于循环流化床锅炉的设计收到了满意的效果,目前多台不同容量和参数的设有内置高温组合式旋涡分离器的循环流化床锅炉已投入稳定的商业运行。     

新技术在100kt/a苯胺流化床反应器上的应用

采用清华大学多项专利专有技术,结合南化公司苯胺生产10多年经验,对苯胺行业传统的鼓泡床进行技术创新。新建成的利用国内技术最大直径的100 kt/a苯胺流化床,不仅实现了鼓泡床向湍动流化床的转变,而且具有产品质量满足MDI企业要求、断面负荷高、操作弹性大、催化剂寿命长等诸多优点。     

浅谈煤气化技术进展及选择

阐述了研究和开发煤气化技术的重要意义，详细介绍了目前国内外主流煤气化技术的进展及应用，比较了各种煤气化技术的优缺点，并对如何选择煤气化技术提出了自己的看法。     

Macroscopic properties of liquid-solid circulating fluidized bed with viscous liquid medium

Experiments were conducted in a liquid-solid circulating fluidized bed to study the effect of liquid viscosity and solids inventory on pressure gradient, critical transitional liquid velocity, onset average solids holdup, axial solids holdup distribution, average solids holdup and solids circulation rate in circulating fluidization regime with riser operated in fixed inventory mode. The results indicate that critical transitional liquid velocity decreases with increase in liquid viscosity. The onset average solids holdup, on the other hand, increases with increase in either auxiliary liquid velocity or solids inventory. The variation of axial solids holdup distribution, average solids holdup and solids circulation rate with liquid viscosity when solid inventory was 0.15 m was dissimilar with either 0.25 m or 0.35 m solid inventory. Correlations were proposed for estimating the average solids holdup and are satisfactorily compared with experimental values.     

Investigation into the viability of a liquid-film three-phase spouted bed biofilter

A variety of technologies exist for the treatment of malodorous air streams, including adsorption, absorption, catalytic combustion, biofiltration and bioscrubbing. Conventional packed bed biofiltration of malodorous substances from waste gas streams has the disadvantages of large unit surface area and relatively uncontrolled design principles. The large bed surface area leads to difficulties in maintaining even moisture and temperature profiles. In addition, the control of such biologically important parameters as pH is difficult. Novel fluidized/spouted beds were studied for biological treatment of gases because of their high specific gas flowrate and vigorous mixing which facilitates enhanced gas–biomass contact. Trials of a range of fluidized and spouted beds, with gas loadings of up to 14000 m³-gas m⁻²-bed h⁻¹, were carried out on various biofilm support media including glass ballotini, rice hulls, plastic discs and granules, silica gel, molecular sieves, vermiculite, perlite, activated carbon, cork, polystyrene and expanded clay. Severe aggregation and wall adhesion restricted the operational range of the reactors. Particle suitability was based on a combination of shape, density, size, porosity and wettability, with large, heavy clay particles performing best. Limited gas-phase bacterial studies on selected media with ammonia- and nitrite-oxidizing bacteria demonstrated the potential of fluidized/spouted beds for efficient biofiltration of ammonia (20–40 mg dm⁻³). © 1998 Society of Chemical Industry     

两种煤气化方式的比较

对两种气化工艺(Lurgi和GSP)从气化方法、煤种、进料要求、气化炉构造及国产化、生产能力、气化炉开车、废水处理方面进行了比较。通过比较,GSP气化比Lurgi气化具有气化煤种更广泛、煤种适应性更强、气化炉构造简单、维修量小、生产能力大、开车快、废水量少且处理系统简单的优点,Lurgi气化比GSP气化具有简单的进料要求、高的设备国产化率、低的氧气消耗、运行业绩较多的优点。为选择气化方式时提供参考。     

Development of a fluidized bed thermogravimetric analyzer

A new fluidized bed thermogravimetric analyzer (FB‐TGA) was developed that introduces two major particularities: the pseudo variation of the weight of the reactor and the special strategy for gas flow rate adjustment according to temperature. A momentum balance was performed on the reactor and the pseudo variation of the reactor weight was evaluated by measuring the pressure drop through the gas distributor and filter. The real weight loss of the reactor was obtained by subtracting the pseudo variation of the weight from the total weight loss measured by the load cell. In addition, a special program for the gas flow rate as a function of temperature was developed and used; so the minimum fluidization regime is maintained throughout all of the experiments. The validation test of the FB‐TGA was carried out on calcium hydroxide decomposition, and the results were compared with those obtained from the conventional TGA. Diffusion control was suppressed by the application of the FB‐TGA, which was confirmed by the x‐ray diffraction analysis on the treated samples. © 2014 American Institute of Chemical Engineers AIChE J, 61: 84–89, 2015     

Calcium sulphide formation in fluidized bed boilers

Analyses of samples of bed ash from a stationary fluidized bed boiler show the presence of calcium sulphide. In some samples, half of the total sulphur was present as sulphide. The samples containing CaS were obtained under unstaged conditions and with a high excess air ratio, 1.3 to 1.4. The samples were taken after a stop in the limestone addition, i.e. at high SO₂ emissions of about 1000 mL/m³ (ppm). No CaS was found during limestone addition when the SO₂ emission was 300–400 mL/m³. This indicates that formation of large amounts of CaS may be initiated as the SO₂ concentration exceeds some critical level.     

Cocurrent Downflow Fluidized Bed Dryer: Experimental Equipment and Modeling

ABSTRACT

Product damage, high energy consumption, and nonhomogeneous final properties are present in typical drying operations such as pneumatic drying, fluidized-bed dryers, and upward circulating fluidized-bed dryers. The downer bed has been shown to be a good technique for this processes. The objective of this work is to test an experimental downflow dryer and model its operation. The equipment consists of a 5-m-high stainless steel duct with 0.17 m i.d. Gas velocity was varied between 0.3 and 8 m/s in co-current solid flow varying between 0 and 50 kg/m²s. Drying rates, pressures, and total flux for solid and gas are determined. Temperature profiles for gas and solid along the radial and axial directions are determined and tested with model predictions. The solid particles were previously dried turnip (Brassica napus) seeds. The equipment shows good operational conditions and facilities for parameter determination, but must be complemented with better equipment for particle concentration determinations. The model's predictions of pressure, gas velocity, solid concentration, and temperature are compared with our experimental values or those reported in the literature.