岩盐溶解速率的研究

在岩盐溶解速率及其影响因素的实验研究基础上,建立了岩盐溶解速率的计算公式。研究的结果可为岩盐开采和其他水溶法矿物开采提供参考。     

提高聚丙烯酰胺溶解速率的技术措施

聚丙烯酰胺是是油田驱油过程中应用最为广泛的一种聚合物,本文简单阐述了聚丙烯酰胺的物理特性,并且从聚丙烯酰胺的溶剂、聚丙烯酰胺的溶解速率等两个方面综述了溶解特点和速溶问题,又总结了加快聚丙烯酰胺溶解的3个技术途径.     

添加剂对农用硫酸钾溶解速率的影响

选择了16种添加剂考察其含量、组分的不同组合以及溶液温度和酸碱度对农用硫酸钾溶解速率的影响。试验结果表明:在硫酸钾溶液中加入1. 0%～1. 5%的磷酸氢二钠、磷酸氢二钠/乙二胺四乙酸二钠、磷酸氢二钠/乙二胺四乙酸二钠/聚乙烯醇磷酸铵等单一组分添加剂或多组分添加剂可将农用硫酸钾的溶解速率提高2～3倍;溶液温度升高和p H降低均能有效加快硫酸钾的溶解速率。     

CO_2微细气泡在NaOH溶液中吸收速率研究

以喷气机械搅拌精炼过程为背景,研究了搅拌方式、喷气流量、搅拌转速等因素对气体吸收速率的影响,通过测定NaOH吸收CO2的速率研究气泡微细化过程,探讨了各种因素对容积传质系数和CO2利用率的影响规律.结果表明,中心搅拌情况下传质系数和气体利用率按单向、间歇和双向模式增加;容积传质系数无论在何种搅拌模式下均随着气体流量的增加而增加,但气体利用率则随着气体流量的增加而呈现先减小后增大的趋势:中心单向搅拌模式下容积传质系数和气体利用率均随着搅拌速率的增加而变小.在实验基础上,应用因次分析原理关联了容积传质系数与相关数群的准数方程,为高温实验的气泡微细化了提供科学和实验依据.     

基于灰度形态学和区域生长的轮胎气泡图像分割

针对轮胎气泡图像复杂的背景斑点纹理,提出基于灰度图像的形态学处理和区域生长的气泡图像分割方法。利用腐蚀后的灰度图像与原图像叠加,增强气泡与背景的对比度,有效地去除了图像中的斑点纹理,在此基础上选取种子点,并通过区域生长法将气泡有效分割。该方法分割出来的气泡位置和面积准确。     

刚性池壁和试验支架对水中爆炸气泡脉动周期的影响

分析了有限水域中气泡的运动状态与无限水域中的差异及刚性池壁对气泡脉动的影响。通过水中爆炸试验,测得了距刚性池壁不同距离处Pentolite的气泡脉动周期。在有试验支架和无试验支架两种条件下,测量了Pentolite和两种RDX基含铝炸药的气泡脉动周期。结果表明,随爆心距刚性池壁距离的减小,气泡周期逐渐变大;试验支架的影响也会使气泡周期变大。     

表面活性物质影响下单个自由上升微气泡传质过程的直接数值模拟

2017年,国际标准化组织将直径介于1～100 μm之间的气泡定义为微气泡,本研究参照上述定义,针对微气泡容易受到表面活性物质影响的特点,通过直接数值模拟对不同尺寸单个自由上升微气泡在表面活性物质影响下的传质速率进行研究.通过与模拟结果对比发现,微气泡的运动速度及传质速率均可用Clift等总结的爬流范围内的理论进行较为...     

同步拉伸速率对双向拉伸聚乙烯薄膜结晶结构及性能的影响

实验采用双向拉伸聚乙烯(BOPE)原料线型低密度聚乙烯(LLDPE),用同步双向拉伸的方法制备BOPE薄膜,研究了双向拉伸过程中拉伸速率对薄膜结构和性能的影响。使用偏光显微镜(PLM)和差示扫描量热法(DSC)对未拉伸聚乙烯流延片的结晶形貌和热性能进行了研究。研究了不同拉伸速率下机器方向(MD)拉伸力的实时变化趋势,用DSC表征了不同BOPE薄膜样品的热性能。发现拉伸速率影响拉伸过程中聚乙烯晶体和分子结构及最终样品的结晶度和晶片厚度分布。实验研究了BOPE薄膜的力学和光学性能,分析了薄膜的宏观性能和分子结构之间的关系。实验结果表明,较高的拉伸速率有利于薄膜性能的提高。     

磷石膏-氨-水固碳反应体系氨浓度对石膏颗粒溶解速率的影响

磷石膏-氨-水固碳反应体系中石膏颗粒的溶解,是三相流化矿化反应系统的控制性步骤。在氨水溶液中石膏颗粒能与氨分子形成N—H…O氢键,导致石膏溶解速率受氨浓度影响。基于已知粒度分布的石膏颗粒群在不同氨浓度下的溶解实验数据,采用种群平衡模型与物料衡算相结合的方法,探究了氨浓度对石膏颗粒群溶解特性的影响规律。结果表明:氨浓度的增加会降低石膏溶解速率,随着溶解的进行,氨对溶解的抑制作用会减弱。此外,随着氨浓度的增大,增加单位氨浓度石膏溶解速率的降幅将变小。结合实验数据拟合关联溶解动力学参数,构建了氨浓度影响下石膏的溶解速率模型,预测了三相流化矿化反应系统中两个串联回路石膏料浆所需的停留时间,为磷石膏-氨-水固碳反应体系矿化烟气CO₂的放大设计提供了理论依据。     

降低湿固化聚氨酯弹性体涂层气泡的技术途径

评述了降低高固体分聚氯酯湿固化弹性涂层气泡的常用技术途径,提出应用硅氧烷封端技术制备聚氨酯弹性体,得到光洁无泡的并具有一定机械性能的厚涂聚氨酯弹性材料.     

Increasing nano‐particle dispersion ratio in the bubble stretching‐based technique

We present a new method to increase nano‐particle migration rate in bubble stretching‐based technique. Vibration created by the inflation and shrinking process of bubbles is used. Process parameters can be adjusted to increase the probability of collision between the nano‐particles and the bubble wall. In effect, particles sufficiently migrate to the bubble wall, increasing both particle migration rate and dispersion ratio. Our measurement show that: (1) particle diameter, initial bubble radius, and initial bubble pressure strongly influence the migration of particles; (2) with appropriate parameters, nano‐particles can quickly and efficiently migrate to the bubble wall through this new method. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

水溶性聚酯合成及其溶解特性研究

研究了SIPM用量和聚合反应条件对酯交换反应速度、产物分子质量的影响,考察了合成产物的结构和碱溶解特性。结果表明:SIPM用量增加,酯交换反应速度下降,当SIPM质量分数由8%增加到12%时,反应速度明显下降,产物分子质量随聚合反应体系余压减小和SIPM用量降低而增大,得到的水溶性聚酯有很好的碱可溶性,减量率随NaOH浓度增加,碱解时间延长,温度提高而增大。     

Rates of drainage-water evaporite salt dissolution in water

Solar evaporators are an important component of systems for managing salts in agricultural drainage water. In California, solar evaporators have been integrated into on-farm drainage management (IFDM) systems as the final stage concentration process following sequential use of drainage water on increasingly salt tolerant crops. In most cases, salts are accumulated in the evaporator basins over a number of years. During months of high precipitation, dry salts redissolve in collected rainwater. Rates of dissolution are important to the design and management of the evaporator to avoid excessive salt concentrations in water displaced from the basin during storm events. The rate at which a solid, dehydrated evaporite salt redissolves in water was simulated and also tested experimentally to validate model predictions. Both model and experimental results show that rain water collecting in an evaporator basin can become saturated within 60 min at 24°C and within 90 min at 10°C with a 0.01 m water depth over solid salt. The thickness of the diffusion layer above the solid surface was calculated in the range of 8.3 × 10^− 5 and 1.25 × 10^− 4 m. For a mostly sodium sulfate evaporite salt, pH increased up to 9 from 5.5 in 5 min, and then decreased slowly converging to about 8.7 due to likely absorption of CO₂ from the atmosphere.     

Effect of resistance internal on hydrodynamic behaviours and bubble characteristics in a laboratory-scale bubble column

A novel resistance internal is proposed to optimize the flow field and improve the gas–liquid contact in a co-hydrogenation reactor of coal and vacuum residuum. Local gas holdup, local liquid velocity, and characteristics of the bubble were investigated in a scaled-down laboratory model. The quantitative results showed that the resistance internals could reduce the thickness of the liquid reflux layer by a percentage up to 32% and reduce the difference in the local gas holdup at cross-sections of up to 44%. The Sauter mean diameter of the bubble decreased from 20.30 to 16.00 mm, which aroused the increase in bubble surface area by a percentage of up to 71.9%. The resistance internal promoted the breakup of the bubble with multiple mechanisms and provided diversion to fluid. In this work, improvement at multiple scales was realized, and the technical support for industrial application was provided.     

铝酸钙粉矿物相红外光谱及铝溶出率分析

铝酸钙粉的结构会受到原料变化的强烈影响。对加入活化剂与未加入活化剂生产的铝酸钙粉进行了相关的结构鉴定与溶出率测定。X射线衍射及热重分析证实,加入活化剂的铝酸钙粉矿物相中含有卤化物,其中矿物相CaAl₃XO₇可能部分水解形成类弗雷德盐的双羟合结构体,这种铝酸钙粉存在2 116 cm^-1及1 981 cm-1两个红外光谱特征峰。矿物相不同,铝酸钙粉的三氧化二铝溶出率有较大差异。     

气水流动中气泡生成体积计算模型的改进

In order to address the bubble formation and movement in air-water two-phase flow,single bubble rising in stagnant water is experimentally studied by digital image processing.Bubbles are released individually from the submerged orifices with different diameters(1.81 mm,2.07 mm,2.98 mm,3.92 mm)at different detachment frequency.Images are recorded by a high-speed video camera and processed by digital image processing technique. The factors impacting the formed volume of bubble are discussed.The experimental results showed that a threshold of gas flow rate(400 mm 3 ·s- 1)divides the bubble formation into two regimes:the constant volume regime and the growing volume regime.Especially for the growing volume regime,the surface tension is taken into account.The bubble volume is consisted of two parts:the surface tension impacting part and the gas volume flow rate impacting part.An improved correlation for bubble volume prediction is developed for the two regimes and better coincidence with the experiment data than the previous models is obtained.     

拟塑性非牛顿流体中在线气泡聚并规律

以拟塑性羧甲基纤维素钠(CMC)水溶液作为非牛顿流体,对在线上升气泡的聚并规律进行了研究。利用光电信号采集系统测定了不同高度的气泡聚并分布规律,分析了气体速度及流体性质等因素对聚并规律的影响。结果表明,在测量高度和实验气速范围内,随着高度升高,在高气速下,气泡聚并率减小,在低气速下,则先增大后减小。2种情况下,达到一定高度后均趋于恒定;在一定高度下,达到一定气速后,气泡聚并率变化较小;中低气速下,聚并率随CMC质量分数增大而减小,而在高气速下,CMC质量分数变化对聚并率影响较小。     

Effect of cooling rate and alumina dissolution on the determination of temperature of critical viscosity of molten slag

In slagging gasifiers with crystalline slag, the fluctuation in temperature near the temperature of critical viscosity (T_cv) can rapidly increase the molten slag viscosity and cause an accumulation of slag inside the gasifier. In order to prevent operational problems caused by the slag, one therefore needs to obtain an accurate measurement of T_cv. The effects of cooling profile and the extent of alumina dissolution on the experimentally determined T_cv were investigated. A synthetic slag was prepared using a composition of Alaskan Usibelli ash, which exhibited crystalline slag behavior, and T_cv was determined under constant cooling and equilibrium conditions. The T_cv measured under 2°C/min of constant cooling was 33°C lower than the T_cv under equilibrium conditions. The effect of alumina dissolution was determined using a platinum (Pt) lined crucible. At a 2°C/min cooling rate, the T_cv measured using a bare alumina crucible was 23°C higher than that from the Pt-lined crucible, offsetting the difference caused by constant cooling. In order to determine a safe gasification temperature range, however, the measurement of T_cv under constant cooling conditions should be avoided.     

一种硅钙钾肥中硅溶出行为的研究

利用单因素法和正交设计法,研究pH、振荡温度和振荡时间对新型硅钙钾肥中硅溶出的影响,并模拟植物吸收养分,测定硅的累积溶出率,验证了其中硅的缓释性。     

基于径向力平衡的鼓泡塔二维流体力学模型

提出了一种鼓泡塔二维轴对称流体力学模型,模型中将气泡所受的升力以及湍动扩散力作为形成塔内气含率稳定分布的主要机制.采用Fluent 6.3流体力学软件求解模型,能得到稳定的二维流场,气含率与液速分布与实验值吻合良好,模型能准确反映表观气速(0.12～0.62 m·s^-1)以及塔径(ø200 mm、ø500 mm、ø800 mm)对流型的影响.利用该模型对更大直径鼓泡塔的流动参数进行了预测,结果与文献给出的经验关联式相符.