改性高岭土抑爆剂对瓦斯煤尘复合爆炸压力的影响

瓦斯煤尘复合爆炸严重影响了煤矿的安全生产,造成了大量的生产损失与人员伤亡。研发能应用在煤矿中高湿低温等复杂环境中的抑爆剂成为了研究的难点与热点。为研发出新型改性高岭土瓦斯煤尘抑爆剂,通过插层改性的方法制备了3种改性高岭土抑爆剂,采用热重分析、扫描电镜和红外光谱分析对样品的热稳定性、表面结构以及官能团变化进行了研究。选用重庆南桐煤样,通过标准筛对煤样进行筛分,通过粒径扫描与扫描电镜观测了煤粉的粒径分布与表面形貌。使用20 L球型爆炸系统对抑制剂抑制瓦斯煤尘爆炸的特性进行了研究,探究改性后高岭土对爆炸最大压力、最大压力上升速率及爆炸峰值时间等爆炸特征参数的影响;基于粉体表征结果及抑爆数据对改性高岭土抑制作用下的瓦斯煤尘爆炸的抑爆机理进行了分析。结果表明:改性高岭土抑爆剂兼具高岭土及插层粒子的双重抑爆效果,改善了高岭土的团聚现象,同时氨基磺酸铵粒子提升了高岭土的热解与抑爆性能。对瓦斯煤尘复合爆炸的抑制性能明显优于改性前粉体,且抑爆效果随着抑制剂质量浓度增加而增大,存在临界质量浓度,试验表明,当改性高岭土与煤尘比例为2∶3,且质量浓度为0.175 g/L时,最大爆炸压力的降幅达到了32.6%,爆炸峰值时间延缓了0.45 s,展现出最佳的抑爆效果。     

丙烯腈废催化剂中铋和镍的浸出分离研究

探讨了酸浸-水解法分离提取丙烯腈废催化剂中铋、镍的工艺条件, 采用先酸浸后水解的方法, 利用硝酸铋的水解特性实现酸浸液中铋、镍的分离。研究结果表明, 在温度80 ℃、反应时间1.5 h、酸浓度3 mol/L、液固比5的最优酸浸条件下, 铋、镍浸出率分别为97.49%和81.81%; 在温度80 ℃、水解时间60 min、液液比8的最优水解条件下, 水解沉淀中铋提取率为89.57%, 水解液中镍提取率为94.86%; 铋、镍的总回收率均可达75%以上。水解沉淀的Bi/Ni值从原料的0.297增大到136.76, 水解液的Ni/Bi值从原料的3.37降低到0.007, 有效实现了铋与镍的分离。     

基于实验设计的L-谷氨酸连续结晶过程优化

对于采用连续振荡挡板式结晶器进行β型L-谷氨酸的冷却结晶,提出一种基于实验设计的晶体产品尺寸分布预测模型和过程操作条件优化方法。将连续管式结晶器的振荡频率、2个区段的降温速率作为操作变量,设计一个包含3因素3水平的响应面实验方案。通过检测不同实验条件下的晶体产品弦长分布,构建一个基于双层基函数的晶体产品尺寸分布预测模型。然后引入一个关于目标晶体尺寸分布和产品收率的目标函数,并且利用上述预测模型,建立一个优化过程操作条件的方法。通过对β型L-谷氨酸冷却结晶过程的仿真和实验,验证了该方法的有效性和优点。     

区间二型模糊免疫PID在环己烷无催化氧化温度控制系统中的应用

环己烷无催化氧化过程具有非线性、多变量耦合、大时滞等特点,使用常规比例积分微分(PID)控制方案无法达到理想的控制性能。提出了一种区间二型模糊免疫PID控制器,其本质上是一种基于免疫PID的非线性控制器,利用区间二型模糊逻辑系统来逼近免疫反馈律中的非线性函数,以提升控制器处理和逼近复杂不确定非线性系统的能力。将所提出的控制器应用于环己烷无催化氧化温度控制系统,仿真结果表明该方法是有效的。     

Incorporating setting information for maintenance‐free quality modeling of batch processes

Typically, the operation condition of the batch process is changed frequently, following different recipes or manufacturing various production grades. For quality prediction purpose, the prediction model should also be updated or rebuilt, which leads to a significant model maintenance effort, especially for those processes which have various phases. To reduce such effort, a maintenance‐free method is proposed in this article, which incorporates the setting information of the batch process for modeling. The whole process variations are separated into two parts: setting information related and other quality related variations. By constructing a relationship between setting variables and other process variables, the data variations explained by the setting information can be efficiently removed. Then, a robust regression model connecting process variables to the quality variable is developed in different phases of the batch process. The feasibility and effectiveness of the proposed method is evaluated through an industrial injection molding process. © 2012 American Institute of Chemical Engineers AIChE J, 59: 772–779, 2013     

Guaranteed cost distributed fuzzy observer‐based control for a class of nonlinear spatially distributed processes

The guaranteed cost distributed fuzzy (GCDF) observer‐based control design is proposed for a class of nonlinear spatially distributed processes described by first‐order hyperbolic partial differential equations (PDEs). Initially, a T–S fuzzy hyperbolic PDE model is proposed to accurately represent the nonlinear PDE system. Then, based on the fuzzy PDE model, the GCDF observer‐based control design is developed in terms of a set of space‐dependent linear matrix inequalities. In the proposed control scheme, a distributed fuzzy observer is used to estimate the state of the PDE system. The designed fuzzy controller can not only ensure the exponential stability of the closed‐loop PDE system but also provide an upper bound of quadratic cost function. Moreover, a suboptimal fuzzy control design is addressed in the sense of minimizing an upper bound of the cost function. The finite difference method in space and the existing linear matrix inequality optimization techniques are used to approximately solve the suboptimal control design problem. Finally, the proposed design method is applied to the control of a nonisothermal plug‐flow reactor. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2366–2378, 2013     

柴油机颗粒捕集器内颗粒沉积结构的实验研究

基于可视化单通道实验系统,采用激光位移测量方法,对柴油机颗粒在陶瓷捕集器内的沉积过程进行了在线测量.研究结果发现,颗粒沉积过程分为4个阶段:深床期、长树期、搭桥期和颗粒层期;颗粒层厚度的增加在长树期迅速增长,而后在颗粒层期呈缓慢增加的趋势.颗粒层过滤期颗粒层的孔隙结构受过滤速度的影响,过滤速度增大,颗粒层的渗透系数和孔隙率减小,形成的颗粒层致密.实验结果证实了当Pe<1时,渗透系数和孔隙率随Pe的增大而减小,且变化显著;当Pe>1时,渗透系数和孔隙率随Pe数的变化趋于平坦.     

基于暂态电流故障分量的直流配电网单极故障选线方法

基于两电平电压源换流器(voltage sourced converter,VSC)的中压柔性直流配电网适合风能、太阳能等分布式能源的接入,但发生单极接地故障时,其故障电流会迅速增大,保护装置必须快速识别出发生故障的线路.针对该问题,分析VSC端的单极接地故障时的暂态特征,对暂态故障电流的变化特征进行理论分析计算.根据...     

Chemical looping glycerol reforming for hydrogen production by Ni@ZrO2 nanocomposite oxygen carriers

The research describes the synthesis of nanocomposite Ni@ZrO₂ oxygen carriers (OCs) and lanthanide doping effect on maintaining the platelet-structure of the nanocomposite OCs. The prepared OCs were tested in chemical looping reforming of glycerol (CLR) process and sorption enhanced chemical looping reforming of glycerol (SE-CLR) process. A series of characterization techniques including N₂ adsorption-desorption, X-ray diffraction (XRD), inductively coupled plasma optical emission spectrometry (ICP-OES), high resolution transmission electron microscopy (HRTEM), H₂ temperature-programmed reduction (H₂-TPR), H₂ pulse chemisorption and O₂ temperature-programmed desorption (O₂-TPD) were used to investigate the physical properties of the fresh and used OCs. The results show that the platelet-stack structure of nanocomposite OCs could significantly improve the metal support interaction (MSI), thus enhancing the sintering resistance. The effect of lanthanide promotion on maintaining this platelet-stack structure increased with the lanthanide radius, namely, La³⁺ > Ce³⁺ > Pr³⁺ > Yb³⁺. Additionally, the oxygen mobility was also enhanced because of the coordination of oxygen transfer channel size by doping small radius lanthanide ions. The CeNi@ZrO₂ showed a moderate ‘dead time’ of 220 s, a high H₂ selectivity of 94% and a nearly complete glycerol conversion throughout a 50-cycle CLR test. In a 50-cycle SE-CLR stability test, the CeNi@ZrO₂CaO showed high H₂ purity of 96.3%, and an average CaCO₃ decomposition percentage of 53% without external heating was achieved.     

在线自适应波长选择方法及其在汽油调和过程中的应用

近红外光谱分析技术作为一种非侵入性的分析手段在工业上得到了广泛应用。然而,大多数近红外模型的波长选择方法是离线建立的,无法有效跟踪过程特性的变化。提出了一种新的在线自适应波长选择方法——在线自适应区间高斯过程回归波长选择方法（adaptive interval Gaussian process regression, AIGPR）,并用于汽油调和过程中的近红外模型的建立。该方法可以根据待测样本的特性对波长结构进行调整。为了降低在线应用的计算成本,该方法分为离线和在线两个部分,离线部分将光谱分割成若干个波长区间,并在每个波长区间上建立局部模型,为在线应用做准备;在线部分中根据划分规则将采样得到待测样本光谱进行分割并代入相应的局部模型中计算波长区间重要性指标,获得最优波长区间。在汽油辛烷值的光谱数据上证明了该方法的有效性。与重要变量投影法和改进的相关系数法相比,该方法具有更好的性能。