一种新型小流量计量泵——气动调频注液泵的研究

本文对用于石化行业中的气动调频注液泵的工作原理和结构进行了探讨,对该泵吸液和注液过程中活塞的运行状态进行了理论分析,提出了有关“残余压力”的理论,通过实验对该部分理论进行了验证,同时对注液泵运动系统质量选择与该泵的频响匹配做了定性研究,为实施最佳结构设计提供了依据。     

谐波对电表计量的影响分析

基于感应式电表与全电子式电表的工作原理,推导出各自在谐波下的数学表达式,并分析出电表计量误差的影响因素,结合理论计算与仿真分析,得到谐波对电表计量影响的结论。     

隧道钢架开孔施工超前小导管的研究与设计

超前小导管是隧道工程施工的一种工艺方法,主要用于不良地质地段的预支护。设计有超前小导管支护的地段,初期支护常以工字钢钢架为主,施工单位常在工字钢腹板中部开小孔来定位超前小导管,以满足间距和角度的要求,特别是当钢架间距较小、作业空间狭小时,都会采取开孔措施方便施工节约时间。开孔后工字钢的支护性能必然下降,监理单位往往不会要求施工单位对开孔后的工字钢架采取补强措施。本文就开孔后工字钢架与未开孔工字钢架做比较,采用力学理论和试验相结合的方法,研究开孔后对工字钢的影响,并探讨其补强措施。     

浅谈高职《高等数学》的教改

在分析现状的基础上,指出了目前在高职院校的高等数学教学中存在的不足,并提出了教学改革的一些设想：以“必需、够用”为原则,修订教材;改革传统的教学方法,淡化系统性和严密性,加强实践教学环节,利用数学软件,充分发挥其在高职人才培养中的作用。     

煤气计量和检测仪表的合理选择

文中对目前焦化企业使用的检测仪表进行了分类与比较，并对适用于焦化厂煤气计量的常用孔板流量计及新式内藏式双文丘里管计量仪表作了详述。     

Abatement of Organic Pollutant Concentrations in Residual Treatment Sludges: A Review of Selected Treatment Technologies Including Drying

As a result of increasing population, industrialization, and effluent quality, sludge production has increased worldwide. Organic micropollutants in sludge have become a more critical environmental health concern compared to heavy metals. New sludge disposal regulations limit persistent organic pollutants (POPs) in addition to conventional organic indicators like total and dissolved organic carbon. This study aims at providing a brief review on POP concentration in the sludge in different regions of the world, sludge regulations, assessment of conventional biological sludge stabilization methods according to their ability to remove POPs, and discussions on alternative sludge treatment methods. The impact of sludge treatment unit operations including conditioning, thickening, mechanical and thermal dewatering, and biological and thermal stabilization on sludge management is also discussed in the context of organics. The occurrence and removal of micropollutants such as absorbable organic halogen compounds (AOX), nonylphenol and nonylphenol ethoxylates (NPE), di-2-(ethyl-hexyl)-phthalate (DEHP), dibenzo-p-dioxins and furans (PCDD/F), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) are also evaluated specifically for sludge treatment unit operations. A concise discussion is also included on different drying technologies suitable for drying of sludge.     

Treatment of 4-chlorobenzoic acid by plasma-based advanced oxidation processes

Studies show that oxidation resistant pollutants are present after conventional water treatment systems. Nowadays a new class of oxidation processes is studied: advanced oxidation processes. Our process is based on the use of an electrical discharge (Glidarc and DBD) to produce HO, which is generated on the surface of a thin film of water. The first results show that the DBD is more efficient than the Glidarc with a degradation efficiency of the target pollutant (4-chlorobenzoic acid (pCBA)) of about 0.87 g kWh⁻¹ for DBD and 0.16 g kWh⁻¹ for gliding arc discharge. However, it appears that secondary reactions due to corrosion of the metallic micro-structured plate cause slower degradation of the pollutant. Moreover, the presence of nitrates in solution after treatment indicates the formation of NO_x in the discharge and the possible formation of nitrogenous oxidation by-products.     

Pilot Plant Results with Three Different Types of UV Lamps for Advanced Oxidation

Three different types of ultraviolet lamps were tested for the advanced oxidation process application on pre-treated surface water in a pilot plant. The pilot setup consisted of three parallel reactors with either medium pressure, low pressure or dielectric barrier discharge UV lamps. Four model compounds (atrazine, bromacil, ibuprofen and N-nitroso-dimethylamine (NDMA)) and 0, 5 or 10 ppm hydrogen peroxide were dosed. Low pressure lamps were shown to have the lowest energy demand, calculated as electrical energy per order, followed by dielectric barrier discharge lamps and then medium pressure lamps. Medium pressure lamps gave the highest formation of genotoxic activity and nitrite formation, whereas no formation of genotoxic activity was observed for either of the other lamp types.     

Multiphase catalytic reactors: a perspective on current knowledge and future trends

ABSTRACT

Conventional and emerging processes that require the application of multiphase reactors are reviewed with an emphasis on catalytic processes. In the past, catalyst discovery and development preceded and drove the selection and development of an appropriate multiphase reactor type. This sequential approach is increasingly being replaced by a parallel approach to catalyst and reactor selection. Either approach requires quantitative models for the flow patterns, phase contacting, and transport in various multiphase reactor types. This review focuses on these physical parameters for various multiphase reactors. First, fixed-bed reactors are reviewed for gas-phase catalyzed processes with an emphasis on unsteady state operation. Fixed-bed reactors with two-phase flow are treated next. The similarities and differences are outlined between trickle beds with cocurrent gas–liquid downflow, trickle-beds with countercurrent gas–liquid flow, and packed-bubble columns where gas and liquid are contacted in cocurrent upflow. The advantages of cyclic operation are also outlined. This is followed by a discussion on conventional reactors with mobile catalysts, such as slurry bubble columns, ebullated beds, and agitated reactors. Several unconventional reactor types are reviewed also, such as monoliths for two-phase flow processing, membrane reactors, reactors with circulating solids, rotating packed beds, catalytic distillation, and moving-bed chromatographic reactors.

Numerous references are cited throughout the review, and the state-of-the-art is also summarized. Measurements and experimental characterization methods for multiphase systems as well as the role of computational fluid dynamics are not covered in a comprehensive manner due to other recent reviews in these areas. While it is evident that numerous studies have been conducted to elucidate the behavior of multiphase reactors, a key conclusion is that the current level of understanding can be improved further by the increased use of fundamentals.     

蒸汽计量系统的改造及实施方案

通过对一个蒸汽计量系统的实施方案的简单介绍 ,为老企业蒸汽计量系统的改造提供了一种新的经济可行的思路。同时简单介绍了软件开发相关的两个关键控件 :Timer控件和MSComm控件。