降低催化裂化干气的几点措施

介绍了影响催化裂化装置干气产率的原因,分析总结了国内外炼厂为降低催化干气产率而采取的几种技术措施。     

CHP-Ⅰ型裂解催化剂的研制

开发的以较小孔径和较高硅铝比的五元环族分子筛为活性组分的 CHP—1型裂解催化剂,用于大庆蜡油或大港直馏柴油的催化裂解制取低碳烯烃具有优良的水热稳定性、优越的低碳烯烃选择性及较高的低碳烯烃产率。从小试到工业试生产证实催化剂制备工艺可行,重复性好,催化剂物化性能亦能满足流化床操作要求。     

±100 Mvar高压STATCOM直接电流分相谐振控制参数整定方法及RTDS仿真实验

高压直流输电换流站采用的是±100 Mvar等级高压STATCOM,对可靠性要求较高,控制系统设计需要较高的响应速度来应对金属性接地故障等极限工况。提出了基于直接电流的分相谐振控制策略,并首次完整地提出了适用于高压STATCOM的参数整定方法。按照该方法设计了南网富宁-广西直流换流站±100 Mvar的控制参数,并通过RTDS硬件在环试验,验证了该参数整定方法的动态响应速度和金属性接地故障穿越。实验结果表明,所提出的直接电流分相谐振控制参数整定方法完全满足±100 Mvar等级高压STATCOM的工程需要。     

DCC装置和丙烯腈装置一体化技术方案

提出DCC装置和丙烯腈装置一体化技术方案,对该技术方案的物料直供、蒸汽综合利用以及酸性气处理技术进行了具体的分析。通过物料互供分析,可以适当减少丙烯的中间储存罐容,提高丙烯从气分装置进丙烯腈装置的温度约5℃,降低装置运行能耗;通过蒸汽综合利用分析,可省去一台4.0 MPa的中压蒸汽锅炉,同时还能提高蒸汽的利用效率;通过对DCC装置酸性气处理技术的分析,发现该技术方案可省去一套与DCC装置配套的LO-CAT硫黄装置。分析表明该组合技术方案有很好的经济效益,省去的一台4.0 MPa中压蒸汽锅炉和一套LO-CAT硫黄装置可为企业节约工程投资1.39×108RMB$;酸性气转化为合格硫酸产品和提高丙烯直供温度,每年可增创效益约3.67×106RMB$。     

DCC／DMAP 催化制备乙酰阿魏酸乙酯

以4－羟基－3－甲氧基苯甲醛为起始原料,合成了中间产物乙酰阿魏酸,再以N,N－二环己基碳二亚胺（ DCC）和4－二甲胺基吡啶（ DMAP）为催化剂,通过酯化反应制备了乙酰阿魏酸乙酯,各步产物通过红外光谱、质谱和元素分析对其结构进行表征确认。实验结果表明：在室温下,催化剂用量为乙酰阿魏酸用量的3％,反应时间为4 h的条件下,产率达到75％,为最优条件。     

一种基于组合外密钥和明文的离散混沌密码算法

利用混沌信号的特性提出了一种新的对称密钥块加密算法。该算法具有如下特点,不直接使用混沌系统参数和初始条件作为密钥,而这些参数由外部密钥和明文字符通过位置加权运算得到,且外部密钥由长度可变的字符串和一正整数组合,密钥空间很大。明文的每一块加密都依赖于密钥和整个明文。仿真结果表明,密文对明文或初始密钥的任何微小变化均有强烈敏感性;密文分布均匀。故该密码系统具有强壮的抵抗攻击的能力。     

直流标准电阻器功率变差的精密测量研究

文中提出了一种精密测量直流标准电阻器功率变差(或电流依赖性)的方法。在直流电流比较仪电阻电桥被测电阻的电流部分增加另外一个1:1直流比较仪量程扩展器,实现被测电阻器测量电流的高准确度倍增;通过与按双电桥内臂串联的两只参考标准电阻的三次比较测量,可以测量倍增电流(功率四倍增加)引起的被测电阻的变化。循环倍增电流,实现对被测电阻功率变差或者电流依赖性的精密测量。实际测量了一只商用10Ω标准电阻的功率变差。结果表明电阻功率变差是二次曲线,与阻值温度曲线具有相似性。     

基于DCC+OSPF协议的光网络组网技术研究

提出了一种基于DCC+OSPF协议的光网络组网技术方案,分析了该方案的关键技术并给出了实现方法,最后对该组网技术进行了验证,试验结果表明该技术方案是正确可行的。     

Modeling and Full Decoupling Control of a Grid-Connected Five-Level Diode-Clamped Converter

This paper presents a novel approach to deal with the regulation of the dc-link capacitor voltages and ac-side currents in a grid-connected five-level diode-clamped converter. Due to the controllability problems of this topology, guaranteeing a solid current control and, mainly, a correct dc-link voltage sharing, represents a complex technical challenge. With the purpose of coping with it, an averaged model that describes the system dynamics at both sides of the converter is presented, assuming that a modulation strategy is integrated in the system to generate the switching sequence. In order to derive the proposed model, no restriction concerning the use of only the three nearest vectors to the desired voltage reference is taken into account. Then, several changes of variables are carried out in the model equations to obtain control input decoupling for control purposes, while reducing the complexity of the model as well. Finally, the voltage and current controllers are designed separately using different control inputs in a straightforward way. Neither auxiliary hardware nor complicated mathematical calculations are required to achieve the control objectives. The effectiveness and good performance of the system under the proposed control approach are validated by simulation results, suggesting that the five-level diode-clamped converter can be a solid solution as an interfacing system connected to the utility grid for, e.g., industrial drives or renewable energy applications.     

Gas-cooled reactor thermal hydraulic analyses with MELCOR

Pursuant to the Energy Policy Act of 2005, the High Temperature Gas-Cooled Reactor (HTGR) has been selected as the reference design for the Next Generation Nuclear Plant (NGNP). Stemming from a U.S. Nuclear Regulatory Commission (NRC) HTGR research initiative, a need was identified for validation of systems-level computer code modeling capabilities in anticipation of the eventual need to perform licensing analyses. Because the NRC has used MELCOR for light water reactors (LWR) in the past and because MELCOR was recently updated to include gas-cooled reactor (GCR) physics models, MELCOR is among the system codes of interest to the NRC. This paper describes MELCOR modeling of the General Atomics' Modular High Temperature Gas-Cooled Reactor (MHTGR). The MHGTR is a suitable design for demonstration of MELCOR GCR modeling competency for two reasons: 1) the MHTGR is a predecessor to the more advanced General Atomics’ Gas-Turbine Modular High Temperature Reactor (GTMHR), and 2) experimental data useful for benchmark calculations may soon become available. Using the most complete literature references available for the MHTGR design, researchers at Texas A&M University (TAMU) constructed a MELCOR input deck for the MHTGR to partially validate MELCOR GCR modeling capabilities. Normal and off-normal system operating conditions were modeled with appropriate boundary and initial conditions. MELCOR predictions of system response were obtained for steady-state, pressurized conduction cool-down (PCC), and depressurized conduction cool-down (DCC) scenarios. Code results were checked against nominal MHTGR design parameters, physical intuition, and anticipated GCR thermal hydraulic response. No inherent deficiencies in MELCOR modeling capability were observed, suggesting that the newly-implemented GCR models are adequate for systems-level analysis. If and when experimental benchmark data becomes available, further validation activities may proceed given the modeling efforts discussed herein.