Simulation study on the gasification process of Ningdong coal with iron-based oxygen carrier

Chemical looping gasification (CLG) of Ningdong coal by using Fe₂O₃ as the oxygen carriers (OCs) was studied, and the gasification characteristics were obtained. A computation fluid dynamics (CFD) model based on Eulerian‐-Lagrangian multiphase framework was established, and a numerical simulation the coal chemical looping gasification processes in fuel reactor (FR) was investigated. In addition, the heterogeneous reactions, homogeneous reactions and Fe₂O₃ oxygen carriers' reduction reactions were considered in the gasification process. The characteristics of gas flow and gasification in the FR were analyzed and it was found that the experiment results were consistent with the simulation values. The results show that when the O/C mole rate was 0.5:1, the gasification temperature was 900 ℃ and the water vapor volume flow rate was 2.2 ml·min^-1, the mole fraction of syngas reached a maximum value of the experimental result and simulation value were 71.5% and 70.2%, respectively. When the O/C mole rate was 0.5:1, the gasification temperature was 900 ℃, and the water vapor volume flow was 1.8 ml·min^-1; the gasification efficiency reached the maximum value was 62.2%, and the maximum carbon conversion rate was 84.0%.     

Experimental determination of gas holdup and volumetric mass transfer coefficient in a jet bubbling reactor

The hydrodynamics and mass transfer characteristics of a lab-scale jet bubbling reactor(JBR) including the gas holdup, volumetric mass transfer coefficient and specific interfacial area were assessed experimentally investigating the influence of temperature, p H and superficial gas velocity. The reactor diameter and height were 11 and 30 cm,respectively. It was equipped with a single sparger, operating at atmospheric pressure, 20 and 40℃, and two p H values of 3 and 6. The height of the liquid was 23 cm, while the superficial gas velocity changed within 0.010–0.040 m·s~(-1) range. Experiments were conducted with pure oxygen as the gas phase and saturated lime solution as the liquid phase. The liquid-side volumetric mass transfer coefficient was determined under unsteady-state oxygen absorption in a saturated lime solution. The gas holdup was calculated based on the liquid height change, while the specific interfacial area was obtained by a physical method based on the bubble size distribution(BSD) in different superficial gas velocities. The results indicated that at the same temperature but different p H, the gas holdup variation was negligible, while the liquid-side volumetric mass transfer coefficient at the p H value of 6 was higher than that at the p H = 3. At a constant p H but different temperatures, the gas holdup and the liquid-side volumetric mass transfer coefficients at 40℃ were higher than that of the same at 20℃. A reasonable and appropriate estimation of the liquid-side volumetric mass transfer coefficient(kla) in a pilot-scale JBR was provided which can be applied to the design and scale-up of JBRs.     

Balanced multiple weighted linear discriminant analysis and its application to visual process monitoring

Visual process monitoring is important in complex chemical processes. To address the high state separation of industrial data, we propose a new criterion for feature extraction called balanced multiple weighted linear discriminant analysis(BMWLDA). Then, we combine BMWLDA with self-organizing map(SOM) for visual monitoring of industrial operation processes. BMWLDA can extract the discriminative feature vectors from the original industrial data and maximally separate industrial operation states in the space spanned by these discriminative feature vectors. When the discriminative feature vectors are used as the input to SOM, the training result of SOM can differentiate industrial operation states clearly.This function improves the performance of visual monitoring. Continuous stirred tank reactor is used to verify that the class separation performance of BMWLDA is more effective than that of traditional linear discriminant analysis, approximate pairwise accuracy criterion, max–min distance analysis, maximum margin criterion, and local Fisher discriminant analysis. In addition, the method that combines BMWLDA with SOM can effectively perform visual process monitoring in real time.     

中国的钛工业概况

对近年来轻水反应堆用锆合金材料的发展及其应用研究中一些主要技术问题和标准要求进行了综合述评。     

下喷式环流反应器环隙气含率影响因素

下喷式环流反应器是一种用于强化气-液两相反应过程的新型装置，虽然已在工业上有了较广泛的应用，但对其理论研究远未成熟，其工业装置的设计仍依赖于实验和经验。本文借助实验室自制实验装置，对下喷式环流反应器环隙气含率的影响规律进行了研究。首先，对喷射器的吸气量进行了测量，获得了不同条件下喷射器最大吸气量的性能曲线；在此基础上，分别研究了气相流量、液相流量以及喷射器安装位置对环隙气含率的影响规律。结果表明：气相流量和液相流量对气含率具有重要的影响，随着气相流量和液相流量的增大，气含率快速提高，而喷嘴位置对气含率的影响相对较小；考虑到增加气相流量和液相流量所需要的能耗和设备代价，通过增加液相流量来达到提高气含率的目的是优选方案。     

气液固三相床中合成甲醇与二甲醚

叙述了气液固三相催化反应技术的主要特点和应用领域，并着重介绍了三相床合成甲醇和二甲醚的试验研究内容和成果。     

基于导数分析的反应器网络综合方法

对反应器网络综合问题进行了研究，分析了瞬时选择性对关键组份组成的偏导数与最佳反应器类型之间的关系，给出了确定最优反应器的三条规则。对δS/δC符号不变的反应体系，用这些规则可获得最优反应器网络。对一般的反应体系，假设了五种典型S－CA曲线所对应的反应过程，分别对不同曲线类型给出了确定最优反应器网络的方法。此外，按本文方法所得的最优反应器网络结构是一个CSTR或PFR或由CSTR、PFR组成的串联结构。由dS/dCA的符号及其变化情况决定。给出了两个说明本文方法的例子，结果表明本文方法简单并可获得与文献相同或相似的结果。     

非冷冻碳化法工业化生产针状纳米碳酸钙

通过开发复合型结晶导向剂,在实验室试验和中试的基础上,实现了在非冷冻(高温35~75℃)、氢氧化钙高浓度(质量分数7%~12%)条件下碳化生产针状(晶须)纳米碳酸钙。将该方法应用在石家庄博达钙业有限公司2.5万T/A的轻质碳酸钙工业装置上,经扫描电镜、透射电镜、X射线衍射和比表面积测定分析表明,产品纳米碳酸钙的晶形为针状,粒度均匀、分布窄,粒径10~20 NM,长径比15~20,比表面积≥90 M2/G,总孔容≥0.26 ML/G。     

撞击流—旋转填料床反应器的微观混合性能研究

采用化学偶合法 ,对撞击流—旋转填料床反应器内微观混合进行了实验研究 ,得到了转速、喷嘴间距、射流速度及浓度等因素对离集指数Xs的影响规律 ,并对其进行了定性的分析。结果表明撞击流—旋转填料床反应器中微观混合能被极大地强化 ,可成为适合快速反应新型反应设备