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关键词： Bubble Rising Velocity   Optical Probe   Internal   Bubbling Fluidized Beds   SIZE  

摘要： The hydrodynamic characteristics of bubbles in bubbling fluidized beds with internals were investigated. The signal range of the optical fiber probe was calibrated from 0.5 V (the bubble phase) to 4.5 V (the emulsion phase). Data sampling involved an optical probe at a rate of 903Hz for 725 s. To obtain improved bubble data, the data were analyzed by three processes: threshold determination, bubble analysis, and erroneous bubble elimination. The data on the bubble rise velocity and bubble frequency were measured and compared to the bed height (0.2-0.7 m), superficial gas velocity (4-7 U (mf) ), radial position r/R (0.22-0.95), number of distributor nozzles (2, 3, and 7), and the use of the internals with different hydraulic diameters of 0.19, 0.17, and 0.15 m. The experimental data were compared with several reported empirical correlations. Both the bubble rise velocity and bubble frequency increased with decreasing number of distributor nozzles. Furthermore, in the presence of internals, the bubble rise velocity decreased, whereas the bubble frequency increased with decreasing hydraulic diameter of the cross-sectional area divided by internals. Moreover, bubble breaking occurred at a specific position of r/R=0.7, not at the edge of the internals.

关键词： Inverse fluidized bed   Superficial air velocity   Biofilm   Hydrodynamics   Biodegradation   AIRLIFT SUSPENSION REACTOR   SMALL SUSPENDED PARTICLES   WASTE-WATER TREATMENT   BIOMASS CHARACTERISTICS   PSEUDOMONAS-FLUORESCENCE   DETACHMENT FORCES   AEROBIC BIOFILMS   MASS-TRANSFER   STEADY-STATE   BIODEGRADATION  

摘要： The influence of some hydrodynamic effects on the performance of biofilm in inverse fluidized bed biofilm reactor (IFBBR) was studied with low-density polystyrene support particles of various sizes (2.9, 3.5, and 3.8 mm) using Pseudomonas fluorescens for the degradation of phenol. The biofilm reactor was operated under different superficial air velocities for a fixed settled bed height of particles to study the effect of hydrodynamics on biofilm thickness, biofilm dry density, bioparticle density, and attached and suspended biomass concentrations for efficient biodegradation of phenol. There is evidence that the chemical oxygen demand reduction and phenol degradation efficiency were found to be high at the optimized superficial air velocity with controlled biofilm thickness and for a stable and dense biofilm dry density. The results of the study revealed that with increase in superficial air velocity, the biofilm thickness and bioparticle density decreases while the biofilm dry density and suspended biomass concentration increases. However, above a critical superficial velocity (optimal superficial velocity) the detachment force does not control the outgrowth of the biofilm anymore and the thickness increases rapidly with decreasing suspended biomass concentration. The optimal superficial velocity for better biodegradation of phenol was found to 0.240, 0.220, and 0.230 m/s for the particle sizes of 2.9, 3.5, and 3.8 mm, respectively. The particle size of 3.5 mm has been found to be the optimal particle size for efficient biodegradation of phenol in IFBBR with better hydrodynamic effects and biofilm morphology.

关键词： Supercritical pressure circulating fluidized bed boiler   Response characteristic   Flow sensitivity   Heat disturbance   Theoretical analysis   HEAT-TRANSFER   CFB BOILER   WALL  

摘要： Under the working conditions of 600 MW supercritical pressure circulating fluidized bed boiler, this paper conducted a theoretical analysis on the response characteristics of mass flow with respect to a heat disturbance within furnace. The main objective has focused on the effects of multiple factors on the variations of flow sensitivity coefficient and the corresponding mechanism was discussed in detail. It was found that the flow sensitivity coefficient decreases with increasing steam quality and increases with increasing heat flux, suggesting a stronger flow sensitivity within low quality range accompanied by a high heat flux. The flow sensitivity is more pronounced for the working condition with low mass velocity. There is a critical mass velocity that can be used as a demarcation line to distinguish the Positive Response Characteristic (PRC) and Negative Response Characteristic (NRC) of mass flow within vertical tube. The effects of pressure are mainly reflected in two aspects as the pressure varies, which are the variations of flow sensitivity coefficient and the critical mass velocity. The mass flow deviations at 40%, 50% and 75%THA are all greater than zero when the heat flux of vertical tube is increased by 30%. The steam deviations of SCFBB are much smaller than those of supercritical pressure coal-pulverized boiler under similar boiler loads, indicating that the SCFBB studied in this paper has distinct advantages in assuring good hydrodynamic performance of water wall. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： 膏体输送管道   压力监测   测压管   压阻式压力传感器  

摘要： 针对膏体材料泵送充填开采过程中输送管道容易出现堵塞、压力失稳等问题,研究开发了压力监测系统、测压管以及压阻式压力传感器,在1861工作面膏体输送管道设置6个压力监测点,实现了管道压力实时监测,及早发现管道堵塞故障和预警管道破损危险,得出管道堵塞压力报警值为4MPa。

关键词： 深空探测器   姿态规划   对数势函数   改进退步法  

摘要： 针对深空探测器姿态约束机动问题,提出一种基于对数势函数的多约束姿态机动规划方法。首先,定义了两种姿态指向约束,即禁止约束和强制约束,并利用禁止约束和强制约束的性质构建了对数势函数作为Lyapunov函数;在此基础上采用改进退步法设计了探测器姿态机动控制器。数值仿真结果表明:该方法不仅在多约束情况下能够自主求出安全的机动路径,而且在分析和求解上计算效率较快,对于星上资源有限的深空探测器具有实际运用价值。

关键词： 生物柴油   正丁醇   密度   黏度   表面张力  

摘要： 本文测量了常压下生物柴油及其与正丁醇混合物的密度、黏度和表面张力数据,温度范围分别为278-363K、313-363 K、293-353 K。对于密度测量,生物柴油的质量分数分别为80%、60%、50%、40%、20%;对于黏度测量,生物柴油的质量分数分别为80%、50%。同时采用不同模型对生物柴油及其与正丁醇二元混合物的密度、黏度、表面张力实验数据进行拟合,结果显示良好,拟合模型与实验数据的最大标准偏差分别为0.01%、1.56%、0.14%。

关键词： 泡排剂   表面张力   耐盐性   耐温性  

摘要： 随着延长气田的持续开发和储量动用程度的提高,气藏出水量和出水气井数不断增多,气井井筒积液和出水影响正常生产等问题逐步显现,针对延气2-延128井区的产水问题,优选出适合本区块的MF-1新型泡排剂,实验主要采用罗氏起泡法对该泡排剂的表面张力、耐盐性能、耐温性能以及现场使用进行评价,结果实验表明,该泡排剂MF-1有着较低的临界胶束浓度、较好的耐温、耐盐性能,且在延气2-延128井区三口气井的现场施工中,取得了较好的效果,达到了排水增产的目的。

关键词： 引嫩渠首工程   坝体渗流   监测   测压管   测设布置  

摘要： 坝体防渗设施设计合理,运行后效果好,工程质量良好。做好土石坝的监测工作,综合利用现代监测技术,剔除误差因素,计算数据的客观、合理,做好计算分析工作,预测危险源。利用渗流分析软件能够对土坝安全监测数据进行有效的处理,从而提高了监测数据的质量,结合利用小波分析可以判断土坝位移的稳定性,大坝安全监测的应用应走专业化的道路。

关键词： 稠油热采   高温复合驱油剂   表面张力  

摘要： 针对高升采油厂稠油热采自营区块多轮吞吐开采后蒸汽吞吐效果逐渐变差[1],高低渗透层矛盾突出;油层压力下降,地层驱动能量不足;油层孔隙内存在的大量剩余油无法有效驱替出来等问题[2],开展了高温复合驱油技术的研究与试验。