生物质惰性颗粒混合物的混合分离特性

在D99mm×1000mm的圆柱流化床中,选用不同粒径的沙子／锯末、沙子／菜籽双组分混合物,研究了不同沉积组分含量,尤其是富沉积组分情形下床层表观气速、静床高度对流化床二组分混合物的混合与分离的影响．实验结果表明：静床高度对生物质惰性颗粒混合物分离指数无影响,沉积组分适宜的粒度及床层高和表观气速有利于生物质惰性颗粒混合物的混合．     

流化床生物质惰性颗粒混合分离特性①

在Φ99×1000mm的圆柱流化床中,选用不同粒径的沙子／锯末、沙子／菜籽体系,研究了不同沉积组分含量,尤其研究了生物质、惰性颗粒在富沉积组分情形下床层表观气速、静床高度对流化床二组分混合物的混合与分离的影响。结果表明静床高度对分高度无影响,沉积组分适宜的粒度及高表观气速有利于流化床二组分混合物的混合,可使混合度达到87％。     

流化床生物质惰性颗粒混合分离特性

在Φ99×1000mm的圆柱流化床中,选用不同粒径的沙子／锯末、沙子／菜籽体系,研究了不同沉积组分含量,尤其研究了生物质、惰性颗粒在富沉积组分情形下床层表观气速、静床高度对流化床二组分混合物的混合与分离的影响。结果表明静床高度对分高度无影响,沉积组分适宜的粒度及高表观气速有利于流化床二组分混合物的混合,可使混合度达到87％。     

灰熔聚冷模流化床中双组份体系颗粒分离特性的研究

本研究采用了等密度及不等密度的三种双组份混合体系，考察了不同分离气速及不同原始配比时沉积组份的分离效率和分离速率；给出了这两种分离特性的定量关联式；提供了达到高效分离（分离效率大于90％）的气速选择范围；得到的分离速率的定量方程能成功预测实际焦粉－灰球混合体系的实验结果，为实际灰熔聚气化炉中分离柱的高效稳定操作提供了依据     

双组分射流床中射流穿透深度的研究

使用多相流模型计算了灰熔聚流态化粉煤气化器中双组分的射流穿透深度。较科学地讨论了模拟计算中射流边界的定义；提出在工业气化器的操作条件下，用基于颗粒个数的算术平均法求混合物的平均直径，从而将双组分问题简化为单组分的计算，求出的射流穿透深度与实验值或文献值比较吻合，并发现床层表观气速的影响较大。     

氨—氢—氮—甲烷混合物气液平衡预测

利用改进的Ｌ－Ｌ二元互作用函数结合简单的ＲＫＳ立方状态方程关联氨－氢－甲烷混合物的６个组分二元系的相平衡实验数据,得到各组分二元系的二元系作用函数的各参数值,后者用来预测该混合物的气液平衡,预测结果和实验值吻合较好。     

生物质焦与煤焦混合物的共流化实验研究

生物质与煤流化床共气化,其混合物料的流化实际上是两者焦的共流化,对其共流化行为特性的研究是共气化工艺过程的基础.实验考察了三种粒径的煤焦分别与两种粒径的玉米芯焦和甘蔗渣焦在不同混合比例下的共流化特性.结果表明,煤焦的加入可以明显改善生物质焦的流化效果,煤焦与生物质焦粒径和密度的差异以及表观气速均影响着混合物的混合分离程度.在实验中,对煤焦与玉米芯焦的混合物,煤焦的粒径普遍小于玉米芯焦的粒径,混合物的最小流化速度随煤焦的质量分数增大而减小,反之,呈现分离状态的物料,其最小流化速度随煤焦的质量分数增加而增加.     

振动重介质流化床细粒焦渣混合物的分选

在间歇振动流化床中研究了细粒焦渣混合物的分离．通过考察细粒焦、细粒渣及细粒焦渣混合物的入选体积量对床层密度和分选效率的影响，得出适宜的操作条件．在此条件下对细粒焦渣混合物进行了分选实验，得到了较佳的分离效率。     

混合物分离单元操作之吸收和蒸馏

分离混合物的方法中,吸收是针对气体混合物的分离,根据混合气体中各组分溶解度的不同实现分离,应用于原料气的净化;回收有用组分;制取液体产品;废气治理等。蒸馏是针对液体均相混合物的分离,根据混合物中个组分挥发度的不同实现分离,应用于产品提纯等。本文通过对吸收和精馏操作的分析,对化工生产过程中实现分离提纯的目的提供一定的理论依据。     

Lee-Kesler状态方程在含极性组分物系粘度计算中的应用

将Ｌｅｅ Ｋｅｓｌｅｒ 状态方程用于Ｄｅａｎ Ｓｔｉｅｌ 粘度方程中求解密度值，计算了８ 组含极性组分的液体混合物粘度，得出较准确的计算结果。     

Particle mixing/segregation in gas-solid fluidized bed of ternary mixtures

The particle concentration profiles and minimum fluidizing velocity of ternary mixtures were investigated experimentally. All the experiments were carried out in an 88 mm I.D. transparent acrylic column containing fluidized beds of ternary particles of different sizes, densities and shape. Mixing/segregation patterns were visualized under different operating conditions. The experimental results are compared with empirical relationships for mixing index and take-off velocity. A new definition of the mixing index, including particle minimum fluidizing velocity and density predicted the mixing/segregation behaviour reliably. The proposed correlation of take-off velocity agrees with the experimental results very well.     

耦合反应器提升管段颗粒速度分布及约束特性

A large-scale cold model experimental setup of a riser-fluidized bed coupled reactor was established according to the olefin reduction technology with an auxiliary reactor for FCC naphtha upgrading.Distributions of particle velocity in the riser section were experimentally investigated in the setup.Furthermore,the restriction index of particle velocity was defined to quantitatively show the restriction effects of the riser outlet lotus-shaped distributor and the upper fluidized bed on the particle flow behavior in the riser.The experimental results showed that the riser could be divided into two regions in the longitudinal direction,i.e.,lower traditional transport region and upper restriction region.In the longitudinal direction,the averaged cross-sectional particle velocity in the traditional transport region increased firstly,and then tended to be smooth,while decreased in the restriction region.With the increase of static bed height in the upper fluidized bed,the local particle velocity decreased,and the tendency of change in the core region is more than that in the wall region.Restriction effects of the lotus-shaped distributor and the upper fluidized bed on particle flow behavior enhanced with the increases of superficial gas velocity,solids flux and static bed height in the upper fluidized bed.In the same cross-section,outlet restriction effects enhanced with the increase of the dimensionless radial position r/R,and would not change when r/R≥0.5.     

Laminar burning velocity and explosion index of LPG-air and propane-air mixtures

The determination of burning velocity is very important for the calculations used in hazardous waste explosion protection and fuel tank venting, which has a direct impact on environmental protection. The scope of the present study encompass an extensive study to map the variations of the laminar burning velocity and the explosion index of LPG-air and propane-air mixtures over wide ranges of equivalence ratio (Φ = 0.7-2.2) and initial temperature (T_i = 295-400 K) and pressure (P_i = 50-400 kPa). For this purpose a cylindrical combustion bomb was developed. The reliability and accuracy of the built up facility together with the calculation algorithm are confirmed by comparing the values of the laminar burning velocity obtained for a standard fuel (propane at normal pressure normal temperature conditions, NPT) with those available in the literature. The burning velocity was determined using different models depending on the pressure history (P-t) of the central ignition combustion process at the minimum ignition energy.The data obtained for the laminar burning velocity is correlated to S_L = S_L0(T/T₀)^α(P/P₀)^β where S_L0 is the burning velocity at NPT, α and β are the temperature and pressure exponents respectively. The value of β is observed to slightly vary with the equivalence ratio for both fuels. However, propane exhibits higher pressure dependency than that of LPG. The maximum laminar burning velocity found for propane is nearly 455 mm/s at Φ = 1.1, while that for LPG is nearly 432 mm/s at 4.5% fuel percent (Φ ≈ 1.5). The maximum explosion index, commonly called the “explosion severity parameter”, is calculated from the determined laminar burning velocity and is found to be 93 bar m/s for propane, and nearly 88 bar m/s for LPG.     

循环流化床提升管中颗粒速度的径向分布及其沿轴向的发展

采用5光纤速度探头对f100mm?5.1m循环床提升管8个高度截面上11个径向位置的局部颗粒速度进行了实验测试,并采用径向不均匀指数(RNI)对颗粒速度径向分布的不均匀性及其沿轴向的变化进行了定量描述。研究结果表明:在高气速、高颗粒循环量操作时,操作条件对颗粒上升速度和下降速度的径向分布的影响在加速段和充分发展段呈现出不同的规律;颗粒上升速度和下降速度沿轴向的变化在核心区和边壁区也表现出不同的趋势。当颗粒循环速率大于200 kgm-2s-1时,颗粒的加速段长度大大延长,以至于大于提升管的高度(15.1m)。颗粒速度径向分布的不均匀性沿轴向是逐渐增大的,并且与截面平均颗粒速度存在很强的相关性。     

Studies on miscibility of polyacrylamide/polyethylene glycol blends

Miscibility studies have been conducted on solutions of blends of polyacrylamide (PAAm) and polyethylene glycol (PEG) over an extended range of concentrations in water. The ultrasonic velocity, viscosity, density, and refractive index of the blends have been measured for different compositions viz., 0/100, 10/90, 20/80, 30/70, 40/60, 50/50, 60/40, 70/30, 80/30, 90/10, and 100/0 of PAAm/PEG blends at 30°C. The interaction parameters such as μ and α have been evaluated using the viscosity data to probe the miscibility. The obtained results have been confirmed by the ultrasonic velocity, density, and refractive index. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2048–2053, 2007     

Ultrasonic,refractometric, and viscosity studies of some polymer blends in solution

Miscibility studies of poly(vinyl pyrrolidone)–polystyrene and poly(vinyl pyrrolidone)–poly(methyl methacrylate) in mixed common solvent (dimethyl formamide + cyclohexanone) have been carried out in different percentages of the blend components. The ultrasonic velocity, viscosity, density, and refractive index have been measured at 30°C. The interaction parameters have been obtained using the viscosity data to probe the miscibility. The obtained results have been confirmed by the ultrasonic velocity, density, and refractive index. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1823–1827, 1998     

水处理絮凝效果综合控制指标研究进展

在分析絮凝相似原则的基础上,综合前人的基础理论和研究成果,对现有絮凝控制指标G、GT、GTRe-1/2、E1t/3T、Eu、Fr等进行了综合对比,阐述了各个指标产生的理论基础及优缺点,并指出现有的絮凝控制指标在一定程度上都存在很大的局限。随着混凝理论的发展和混凝动力学研究的深入,在大量试验的基础上,迫切要求出现更符合实际、更科学的新的参数。     

图像法用于流化床颗粒混合特性的研究

利用基于相关的图像法速度测量技术,测量了小型二维气固流化床密相区颗粒运动速度分布.并提出了用颗粒速度不均匀指数来衡量流化床内颗粒的速度波动与混合.速度波动对于物料扩散与对流混合均十分重要.在流化床下部,颗粒运动速度往往低于床层表面,但速度不均匀指数则高于床层表面.在床层底部颗粒速度不均匀指数随流化床气泡产生而变化.床层内部混合以对流及扩散为主,而在床层表面,混合以对流为主.床层下部速度波动有利于颗粒在床内的扩散及对流混合.流化风量的增加可以增强颗粒的混合.针对这些结论,在流化床垃圾焚烧炉的设计中,对不同的组分选用不同的给料方式,可以促进物料在床内的混合.     

带中心管的两股催化剂颗粒混合预提升结构中的流动特性

在一套大型冷模实验装置上,采用光纤测量系统考察了带中心管的两股催化剂颗粒混合预提升结构内固含率和颗粒速度的分布,以径向不均匀指数对固含率和颗粒速度径向分布进行定量描述,并与不同的预提升结构进行对比. 结果表明,带中心管的预提升结构沿轴向可分为底部、中心管和提升管区,各区固含率和颗粒速度径向分布均匀程度为提升管区>底部区>中心管区;提升管区内1.3~2.3 m间存在一固含率和颗粒速度分布均匀截面;与无中心管的预提升结构和传统预提升结构相比,本实验结构固含率径向分布更均匀,有利于油剂接触;确定了截面平均固含率的影响参数为终端固含率es', Froude数Fr和轴向高度/提升管直径h/Dr;由实验数据回归出预提升结构内截面平均固含率轴向分布的经验模型,计算值与实验值吻合较好.     

Miscibility of Polycarbonate/Polyvinylpyrrolidone and Polycarbonate/Polyethylene Oxide in Chloroform by Viscosity,Ultrasonic and Refractometric Methods

Abstract

Miscibility studies of polycarbonate/polyvinylpyrrolidone (PC/PVP) and polycarbonate/ polyethylene oxide (PC/PEO) in common solvent chloroform were carried out in different percentages of the blend compositions. The viscosity, ultrasonic velocity, refractive index and density were measured at 30[ddot]C. The interaction parameters were obtained using the viscosity data to probe the miscibility. The obtained results were confirmed by the ultrasonic velocity, density and refractive index measurements.