Numerical Simulation of Pressurized Spouted Fluidized Bed for Coal Semi-Gasification

Numerical simulation study is conducted for a pressurized spouted fluidized bed coal carbonizer, in which hydrodynamics of pressurized spouted fluidized bed, chemical reactions and energy balance are taken into account. The effect of operating conditions such as bed pressure, air and steam mass flow ratio, temperature on product compositions in the bed is investigated. According to the calculated results, bed pressure and bed temperature have the key effects on coal semi gasification.

Analysis of Gas-Solid Flow Characteristics in a Spouted Fluidized Bed Dryer by Means of Computational Particle Fluid Dynamics

In order to grasp the particle flow characteristics and energy consumption of industrial fluidized spouted beds,we conduct numerical simulations on the basis of a Computational Particle Fluid Dynamics(CPFD)approach.In particular,the traction model of Wen-Yu-Ergun is used and different inlet conditions are considered.Using a low-speed fluidizing gas,the flow state of the particles is better and the amount of particles accumulated at the bottom of the bed wall becomes smaller.For the same air intake,the energy loss of a circular nozzle is larger than that of a square nozzle.

Catalytic Partial Oxidation of Methane with Air to Syngas in a Pilot-Plant-Scale Spouted Bed Reactor

On the basis of hydrodynamic and scaling-up studies, a pilot-plant-scale thermal spouted bed reactor (50 mm in ID and 1500 mm in height) was designed and fabricated by scaling-down cold simulators. It was tested for making syngas via catalytic partial oxidation (CPO) of methane by air. The effects of various operating conditions such as operating pressure and temperature, feed composition, and gas flowrate etc. on the CPO process were investigated. CH4 conversion of 92.2% and selectivity of 92.3% and 83.3% to CO and H2, respectively, were achieved at the pressure of 2.1 MPa. It was found that when the spouted bed reactor was operated within the stable spouting flow regime, the temperature profiles along the bed axis were much more uniform than those operated within the fixed-bed regime. The CH4 conversion and syngas selectivity were found to be close to thermodynamic equilibrium limits. The results of the present investigation showed that spouted bed could be considered as a potential type of chemical reactor for the CPO process of methane.

Comparison of numerical simulations and experiments in conical gas–solid spouted bed

Flow behavior of gas and particles in conical spouted beds is experimentally studied and simulated using the twofluid gas-solid model with the kinetic theory of granular flow.The bed pressure drop and fountain height are measured in a conical spouted bed of 100 mm I.D.at different gas velocities.The simulation results are compared with measurements of bed pressure drop and fountain height.The comparison shows that the drag coefficient model used in cylindrical beds under-predicted bed pressure drop and fountain height in conical spouted beds due to the partial weight of particles supported by the inclined side walls.It is found that the numerical results using the drag coefficient model proposed based on the conical spouted bed in this study are in good agreement with experimental data.The present study provides a useful basis for further works on the CFD simulation of conical spouted bed.

Prediction of Minimum Spouting Velocity at Elevated Pressures and Temperatures

Minimum spouting velocity （Ums） is one of the most important flow characteristics for proper design and operation of spouted bed reactors. Many correlations for Ums have been published since spouted bed technology was initiated in 1955. In this paper, a new correlation is developed for Ums based on 767 published experimental data covering both high pressure and high temperature conditions. The calculated and the measured results of Ums are in better agreement than other published correlations.

Progress in research of process intensification of spouted beds:A comprehensive review

The development of intensification technology for spouted beds has become a current research focus,and an effective way to improve the efficiency of spouted beds is to reform their structure.Although numerous studies have been conducted on conventional beds,there are few reviews on the comprehensive application of intensification technology for spouted beds.In this paper,we comprehensively review the role of intensification technology in spouted beds for use in hydrodynamics,drying,desulfurization,pyrolysis,coating,biomass and waste gasification,and biomass drying from the perspective of experiment and simulation.Finally,potential problems and challenges in current spouted-bed research are summarized.

Experiments and Modeling of the Preparation of Ultrafine Calcium Carbonate in Spouted Beds with Inert Particles

A novel reaction-drying process was carried out in a spouted bed reactor with inert particles and used to prepare ultrafine CaCO3 particles. Effects of concentrations of CO2 and Ca(OH)2, and reaction temperature on Ca(OH)2 conversion were experimentally investigated. The particle sizes and composition of CaCO3 produced were characterized with transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results indicated that ultrafine CaCO3 particles with mean size of 80 nm could be obtained with this novel process.By modifying the Arrhenius Equation and considering the Ca(OH)2 state, a kinetic model was established to describe the process in the spouted bed. The model parameters estimated from the reaction-drying experiments were found to fit well the experimental data, indicating the applicability of the proposed kinetic model.

Gas Residence Time Distributions in a Spouted Bed

In a spouted bed of 80mm in ID and 1700mm in height, the gas residence time distributions at different radial positions in both spout and annular area were measured with five different kinds of particles as spouting material, air as spouting gas, and hydrogen as tracer. The effects of superficial gas velocity, operating pressure, particle size and its category on gas residence time distribution were discussed. It was found that the gas velocity profile in spout was more uniform than that in annulus. It could be concluded that the gas flow in the spout could be treated as a plug-flow, while that in the annulus inhibited a strong non-ideal flow behavior. Increasing the superficial gas velocity and decreasing the operating pressure, the particle density and its size gave rise to spouting disturbance, thus the measured tracer concentrations vs. time curves fluctuated. The variances of residence time distribution curves could be taken as a measure of the gas fluctuation degree.

Optimization of Draft Tube Position in a Spouted Bed Reactor using Response Surface Methodology

Optimization of draft tube position in a spouted bed reactor used for treatment of wastewater containing low concentration of heavy metals is investigated in this paper. Response surface methodology is used to optimize the draft tube height, the draft tube width and the gap between the bottom of the draft tube and the inlet nozzle. It is observed that the draft tube with a height of 60 millimeter, width of 12 millimeter and the gap of 13 millimeter between its bottom and inlet nozzle, results in optimum value of minimum spouting velocity, measured 45 cubic centimeter per second (2.7 Liter per minute) .

碱回收炉溜槽冷却系统工艺安全研究

通过对碱回收炉溜槽冷却系统工艺安全的研究,分别从正常运行、非正常状态下,对溜槽存在的安全风险进行分析,重点探讨了多工况时,溜槽冷却系统的工艺安全设计,从而能够最大可能避免因溜槽冷却系统故障而造成的安全事故。

多组分气固射流床流动特性 Ⅰ.压力波动的测试装置与数据处理方法

开发了一套具有多路循环，现场显示功能的压力测试装置。在３００×５０ｍｍ二维气固射流床中采用多组分混合物，对带有喷口的气固流化床的三种流型：气泡串、射流、喷流进行了分段功率谱、压力波动的直方图和概率统计分析的研究。并报导了混合物的功率谱密度图及直方图。

基于Host Link通信的燃气炉自动控制系统

介绍了基于高速调温烧嘴燃气加热炉的全自动计算机智能控制系统的方案,实现自动点火、自动监测火焰、脉动式燃烧、自动控温、熄火报警保护、数据的显示与记录等功能,并采用CPM1AH的Host Link通信功能及智能PID控制技术,合理优化控制,使燃气在炉内能充分燃烧。采用燃气炉自动控制系统,既节省能源,又减少了大气的污染,同时保护了环境。

高铁车站室外消火栓系统分压供水探讨

为使高铁车站室外消火栓系统实现分压供水,同时满足相关规范的要求,对GB 50974-2014《消防给水及消火栓系统技术规范》、TB 10010-2016《铁路给水排水设计规范》和TB10063-2016《铁路工程设计防火规范》等规范进行了对比分析研究。明确了不同类型高铁车站室外消火栓系统的管网布置要求:无充实水柱要求的高铁车站室外消火栓系统可与客车给水系统合用管网,采用低压系统;有充实水柱要求的高铁车站室外消火栓系统应采用临时高压系统,并与室内消火栓系统合用管网;无室内消火栓系统的高铁车站供水站,室外消火栓系统应单独设置,采用临时高压系统。

飞机喷口滑油泵试验台液压系统的设计

分析了飞机喷口滑油泵液压试验台的设计要求与难点,提出了设计方案,有效地解决了大流量、高精度、高温的闭式液压系统设计以及复杂的油泵斜盘角度测量机构的设计难点,该试验台具有精度高、结构紧凑、操作使用方便、维护简易等优点。

大空间工业建筑不同送风方式下的空调系统能耗比较

针对上海某大空间工业建筑,运用EnergyPlus模拟软件,对两种不同送风方式下的空调系统建立模型。对比分析实测获得的空调系统能耗与相同室外气象参数和室内空气参数条件下的空调系统模拟能耗,验证了模型的准确性;并对两种送风方式下的空调系统进行了全年能耗的模拟比较,结果显示:整个夏季采用柱状下送风的空调系统能耗较喷口上侧送风节能20.2%,整个冬季柱状下送风较喷口上侧送风节能66.2%,全年柱状下送风较喷口送风节能27.3%。这为降低我国大空间工业建筑的空调系统能耗提供了一定的借鉴与参考。

浅海海底管线维修工作舱

浅海海底管线、电缆检测与维修装置是一种新型的海上装备,它能潜入海底自动探测跟踪海底油气管线,并能准确定位、坐底进行检测和维修。维修工作舱是该装置的重要组成部分,它能提供一个无水作业空间,使维修人员可以在水下对破损的管线、电缆进行维修更换。

CFD-DEM simulation of high density particles fluidization behaviors in 3D conical spouted beds

The spouted bed has been used in the coating process of high-density nuclear fuel particle.The particle fluidization behaviors in pseudo-2D and 3D spouted beds were simulated and validated.The effects of four independent variables(cone angle,particle density,inlet gas velocity,and particle loading)on particle fluidization behaviors in the 3D spouted bed were investigated systematically.The cone angle effect on fluidization mechanism was studied quantitatively first time.A new fluidization quality index was proposed based on the particle entrainment principle,and an extreme value was obtained when the cone angle was 60°,considered to be the optimum value for the 3D conical spouted bed.It was indicated the gas–solid contact efficiency can be kept up if the gas velocity was proportional to ρ_(p)^(0.65) and N_(p)^(0.78) when the particle density or loading was increased.These results will be useful for geometry and operation parameters design of the 3D conical spouted bed and helpful for developing the fluidization mechanism of high-density particles.

汽车转向臂轴环形喷油机及其控制系统设计

针对汽车转向臂轴喷油工序存在自动化程度低、喷油质量差等不足,设计了汽车转向臂轴环形喷油机及其控制系统。对汽车转向臂轴环形喷油机的机械系统进行了详细设计,包括自动喷油装置、动力环形滚筒线、回油盒等;采用可编程序控制器(PLC)作为控制系统的主控制器,实现多种规格汽车转向臂轴的自动喷油;依据汽车转向臂轴规格的不同,通过图形操作终端(GOT)设置和调整生产参数。该设备已投入实际生产使用,运行结果表明,整机性能稳定,运行状况良好,喷油周期为5 s,满足高柔性化、高效率、高质量的自动化生产要求。

室内湿式自动喷水灭火系统设计和施工实践

结合近年来对湿式自动喷水灭火系统的施工和调试经验 ,从管材的选用、流量检测孔板的设置、过滤器的设置等方面 ,提出了对目前高层建筑内湿式自动喷水灭火系统设计和施工中应注意的几个问题。