Sulfur Reduction in FCC Gasoline with a Commercial Additive: A Microactivity Study

The use of advanced FCC catalysts and additives to reduce sulfur in gasoline remains the preferred option to refiners because of its economic and operation incentives. The performance of a commercial sulfur-reducing additive blended with a fresh RE-USY catalyst was assessed in a microactivity (MAT) unit using Arabian Light vacuum gas oil (VGO). The additive was evaluated at different concentrations (0-15 wt%) in terms of sulfur reduction capability and its effect on product yield structure, mainly gasoline. At 5 wt% additive, the results showed a 14 wt% reduction in total gasoline sulfur with minor effect on catalytic activity and product selectivity. Minimal reduction capability was observed towards benzothiophene (BT), which is difficult to crack and remove under cracking conditions. Upon increasing additive concentration to 10 wt%, total sulfur was reduced to 21 wt% compared to 27 wt% reduction at 15 wt% additive. At this additive concentration, aromatic sulfur compounds mainly C4-thiophenes and a portion of BT were cracked to tetrahydrothiophene, or thiophene, which were subsequently cracked to H₂S and light gases.     

Modeling and real‐time simulation of UPFC

We have developed a digital real‐time simulator of Power Electronics Controllers, so‐called FACTS (Flexible AC Transmission Systems) Controllers and/or Custom Power by using MATLAB^TM/SIMULINK^TM and dSPACE^TM System. This paper describes the modeling and the calculation accuracy of a UPFC (Unified Power Flow Controller) model. Hence, the developed simulator operates at a large time step, in order to improve simulation accuracy, a correction processing of the switching delay is implemented into the UPFC model. Calculation accuracy of the real‐time UPFC model is at the same level as EMTDC^TM results. We confirm stable operation of the developed UPFC model by connecting a commercial real‐time digital simulator (RTDS^TM). © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(1): 19–26, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20200     

Sulfur Reduction in FCC Gasoline with a Commercial Additive: A Microactivity Study

Abstract

The use of advanced FCC catalysts and additives to reduce sulfur in gasoline remains the preferred option to refiners because of its economic and operation incentives. The performance of a commercial sulfur-reducing additive blended with a fresh RE-USY catalyst was assessed in a microactivity (MAT) unit using Arabian Light vacuum gas oil (VGO). The additive was evaluated at different concentrations (0–15 wt%) in terms of sulfur reduction capability and its effect on product yield structure, mainly gasoline. At 5 wt% additive, the results showed a 14 wt% reduction in total gasoline sulfur with minor effect on catalytic activity and product selectivity. Minimal reduction capability was observed towards benzothiophene (BT), which is difficult to crack and remove under cracking conditions. Upon increasing additive concentration to 10 wt%, total sulfur was reduced to 21 wt% compared to 27 wt% reduction at 15 wt% additive. At this additive concentration, aromatic sulfur compounds mainly C4-thiophenes and a portion of BT were cracked to tetrahydrothiophene, or thiophene, which were subsequently cracked to H₂S and light gases.     

高产虫草素的蛹虫草新品种选育

虫草素(3'-脱氧腺苷)具有抗肿瘤、抗菌、抗病毒、增强免疫力等多种生物活性功能,是蛹虫草(Cordyceps militaris)的核心生物活性物质.目前,蛹虫草中虫草素含量还偏低,且蛹虫草菌株易退化,急需选育高产优质的蛹虫草新菌株.作者以高产虫草素的蛹虫草CM17菌株和高产子实体的蛹虫草ZGCM菌株为亲本,从ZGCM...     

稀土离子半径对Y分子筛抗Ni性能的影响

采用液相离子交换法制备了CeY、NdY、HoY 分子筛,并通过Mitchell等体积浸渍法对其进行Ni污染。运用氨气程序升温脱附(NH3-TPD)和原位吡啶红外光谱技术(InsituPy-FTIR)对其酸性质进行表征,采用微反应活性评价装置考察其抗Ni性能。结果表明,随着稀土离子半径的减小,稀土改性Y 型分子筛抑制Ni破坏其B酸中心能力逐渐增强。进一步将酸性关联活性后发现,经Ni污染后REY 分子筛的催化裂化微反应活性亦随着稀土离子半径的减小而逐渐增强,且反应液相产物中汽油质量分数随Ni/REY分子筛催化剂中RE离子半径的减小而逐渐增加。RE离子半径越小的REY分子筛抗Ni性能越好。     

基于VPN的MAT900型质谱仪远程共享系统

在X Window system基础上,提出了一种结合VPN与SSH技术的科学仪器远程共享解决方案。在远程客户端建立X server服务,实现测控软件输入输出重定向功能。利用VPN与SSH网络技术构建三层网络结构,控制系统访问权限,保护数据安全传送。提供文件、图像、语音等协同服务。通过远程操作测控软件,实现科学仪器的远程控制。应用该方案成功实现了MAT900型质谱仪的远程共享。该方案也适用于UNIX/Linux平台下各类科学仪器测控软件的远程操控。     

A divide and conquer algorithm for medial surface calculation of planar polyhedra

The Medial Axis Transform surface, (or MAT or MS) is proving to be a useful tool for several applications and geometric reasoning tasks. However, calculation of the MAT is a time-consuming task and the benefits of the mathematical-based tool are offset by the cost of the calculation. This paper presents a method for medial surface calculation which uses subdivision to simplify the problem and hence speed up the calculation, a so-called ‘divide-and-conquer’ approach. The basis for this is a modification of the dual structure of the original object. As the calculation proceeds this structure is broken up into sub-pieces each representing a simpler sub-part of the MAT. Perhaps more importantly, this method creates a correct node decomposition of the dual structure. The paper goes on to demonstrate some applications of the results for geometric tasks, specifically offsetting and model subdivision, which are normally expensive but are simpler based on the MAT calculation results.     

MATLAB软件在锅炉水位模糊控制系统中的应用

利用模糊控制理论设计锅炉水位控制系统 ,并应用MATLAB软件对该模糊控制系统进行验证和仿真 ,以实现对锅炉水位的最佳实时控制。     

A subband coding approach to control under limited data rates and message losses

For the design of networked control systems, we employ a subband coding technique to efficiently use the available data rate. Such coding schemes have widely been used in signal processing for data compression. We take an approach suitable from the control perspective in that frequency characteristics of a controller are directly used. In particular, we propose a three-step design procedure for the overall controller having the following features: On the coder side, it uses a controller consisting of a filter bank whose outputs are subband signals of the control input. On the decoder side is another filter bank for reconstruction of the subband signals. This decoder is capable to account for random message losses that occur in communication and is designed via an H^∞-type method. For the quantizers in the coder, an efficient bit allocation scheme is also developed.     

面向HPC互连网络的低延迟前向纠错编码研究与实现

当前主流高性能互连网络的端口速率已达到100~400 Gbps,其单通道速率已达到25~50 Gbps。在这种高速率的网络上传输数据,前向纠错编码是提高其可靠性的必要技术。以太网国际规范IEEE 802.3采用的前向纠错编码为RS(528,514)和RS(544,514),但是这2种码型难以满足高性能互连网络在低延迟方面的性能需求。首先,分析了RS的编码和译码结构,并定量研究了RS码型参数与编解码延迟之间的关系。接着,提出了一种面向当前高性能互连网络的新型低延迟编码—RS(271,257),并比较了该码型在占用带宽和纠错能力等方面的优缺点。最后,实现了基于RS(271,257)的低延迟网络编码子层,并对其进行了资源消耗评估和延迟性能模拟。综合考虑资源消耗、纠错能力和延迟性能3方面因素,RS(271,257)是一种理想的低延迟前向纠错码型,可满足当前面向HPC的低延迟高性能互连网络的编码子层的设计需求。