合成氨一段炉炉顶烧嘴偏烧原因分析

公司合成氨装置一段炉近几年存在严重的超温、偏烧和温度波动现象。经过长期深入分析,从烧嘴类型、配风系统、炉型结构、燃烧介质、触媒以及设备方面逐一进行原因排查、处理,最终有效解决了这一长期困扰工艺生产的难题。对该过程进行分析总结,为今后一段炉的进一步优化拓展思路。     

天然气制乙炔生产PVC工艺简介

简介了我国首条以天然气为原料生产PVC树脂装置的基本情况,并从工艺先进性、工艺运行稳定性及装置的经济性3方面评价了天然气制乙炔工艺路线。     

CFD simulations of quenching process for partial oxidation of methane:Comparison of jet-in-cross-flow and impinging flow configurations

A new quenching process using the cold pyrolysis gas has been proposed for the partial oxidation (POX) of methane to recover the heat.The mixing of hot product gas and cold pyrolysis gas in milliseconds is critical to this new approach.Two most widely-used rapid mixing configurations,i.e.the jet-in-cross-flow (JICF) and impinging flow configurations,are compared in terms of mixing and quenching performances using computational fluid dynamics (CFD) coupled with detailed reaction mechanism Leeds 1.5.The mixedness,residence time distribution,temperature decreasing rate and loss ratio of acetylene during the quenching are systematically studied.The results show that the impinging flow has a more uniform mixing and narrower residence time distribution than the JICF.However,the temperature decreasing rate of the mainstream is faster in the JICF than in the impinging flow.The loss ratio of acetylene in the quenching process is 2.89％ for the JICF and 1.45％ for the impinging flow,showing that the impinging flow configuration is better and feasible for the quenching of POX of methane.     

Enhanced process comprehension and quality analysis based on subspace separation for multiphase batch processes

Phase‐based subpartial least squares (subPLS) modeling algorithm has been used for online quality prediction in multiphase batches. It strictly assumes that the X – Y correlations are identical within the same phase so that they can be defined by a uniform regression model. However, the accuracy of this precondition has not been theoretically checked when put into practical application. Actually it does not always agree well with the real case and may have to be rejected for some practical processes. In the present work, it corrects the “absolute similarity” of subPLS modeling by a more general recognition that only one part of the underlying correlations are time‐wise common within the same phase while the other part are time‐specific, which is referred to as “partial similarity” here. Correspondingly, a two‐step phase division strategy is developed, which separates the original phase measurement space into two different parts, the common subspace and uncommon subspace. It is only in the common subspace where the underlying X – Y correlations are similar, a phase‐unified regression model can be extracted for online quality prediction. Moreover, based on the subspace separation, offline quality analyses are conducted in both subspaces to explore their respective cumulative manner and contribution in quality prediction. The strength and efficiency of the proposed algorithm are verified on a typical multiphase batch process, injection molding. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

Local power of likelihood‐based tests for cointegrating rank: Comparative analysis of full and partial systems

This note investigates local power properties of likelihood‐based cointegrating rank tests for partial and full vector autoregressive systems. The asymptotic distributions of partial likelihood‐based tests under local alternatives are derived, depending on various specifications of deterministic terms. A simulation study is then performed using both the full and partial systems. It is demonstrated that the rank tests based on the partial system, if a required parametric condition is fulfilled, can be more powerful than those based on the full system. This finding encourages testing cointegrating rank using a partial system as well as a full system, in such circumstances as the parametric condition could be satisfied.     

FBMC-OQAM系统中一种改进的OPTS算法

针对采用重叠部分传输序列(overlapping partial transmit sequence,OPTS)算法来抑制滤波器组多载波-偏移正交幅度调制(filter bank multicarrier-offset quadrature amplitude modulation,FBMC-OQAM)信号的峰均比(p...     

一种使用区块链保护车联网数据隐私的方法

随着物联网的快速发展和成熟,汽车工业领域的应用正经历着从早期的车辆Ad-Hoc网络到车联网的快速转变,数以万计的车辆及其搭载的各种车载设备都将通过车联网实现车辆或驾驶数据的共享和交互,而这些海量的数据的存储以及其中的大量用户隐私和数据安全问题带来巨大的挑战,尤其是访问控制、信任和密钥托管问题.针对该问题提出了一种基于区...     

证券市场中庄家与散户间的确定性微分博弈

基于确定性微分博弈理论,建立了一种庄家与散户间的连续时间的博弈模型.首先将所有散户作为一个整体与庄家进行博弈,以博弈双方持股率的动态关系作为动态系统方程,并以此构建了一个确定性微分博弈模型; 然后运用开环纳什均衡和反馈纳什均衡分别求解出满足共态函数的常微分方程组和满足价值函数的Issacs - Bellman偏微分方程,以此得到庄家与散户博弈的开环纳什均衡策略和反馈纳什均衡策略.该结果可为金融监管部门监管证券市场和证券市场投资者买卖股票提供参考.     

游离氨对活性污泥系统中硝化性能和硝化群落结构的影响

建立了4个平行的SBR处理合成废水,游离氨(FA)浓度分别为0.5、5、10、15 mg/L,命名为S0.5、S5、S10和S15,4个系统的脱氮性能在整个实验过程中均很好(平均值为98.7％),利用FA对亚硝酸氧化细菌(NOB)的抑制作用,结合过程控制,成功在S10和S15系统中实现短程硝化.在建立短程硝化途径的过程...     

一类广义 KdV 方程孤立子解的传播及其性质

利用行波方法研究了一类广义的Ｋｏｒｔｅｗｅｇ－ｄｅＶｒｉｅｓ（ＧＫｄＶ）方程的孤立子解及其性质，给出了含有一个参数的孤立子解族，研究了当参数发生变化时孤立子解的变化规律及其全部过程．所得结果很好地揭示了非线性系统中非线性因素的作用，即无论非线性因素多么小，它总会导致孤立子现象的出现．同时利用数字方法研究了该类广义ＧＫｄＶ方程的多个孤立子共存并相互作用的现象．