制约空压机长周期运行的因素及处理措施

通过对引进C150MX3型空压机近几年来的运行和故障情况的分析,得出制约空压机长周期运行的3个因素:冷却器结垢、扩压器腐蚀和二级振动值高。分析了引起故障的原因,并采取了相应措施,实现空压机长周期稳定运行。     

空压机叶轮结垢原因及处理措施

通过对新空分装置空压机近年来运行和故障的分析,得出造成空压机叶轮结垢的主要原因是机组进口过滤器的过滤效果差、空压机级间管道和冷却器内壁锈蚀。分析引起故障的原因,并采取相应的措施,实现空压机长周期稳定运行。     

保持空压机稳定运行的措施

通过介绍引进的3MSGEP-16/15型空压机近几年来的运行状况,浅析影响空压机稳定运行的因素:喘振、冷却器结垢及堵塞、二级振动值高。阐述为实现空压机长周期稳定运行而采取的措施。     

空压机的不稳定工况及对空分设备的影响

详细介绍了齐鲁石化公司第二化肥厂空压机组C/T-151发生的三次故障、处理措施及从中获得的经验和教训,分析了空压机不稳定故障的原因,最后分析了空压机不稳定运行对空分设备的不良影响。表3。     

60000m~3/h空分设备空压机停车故障分析与处理

由于60000 m3/h空分设备配套的VK200-3型空压机导叶开度偏差控制故障和一级导叶无规律窜动,导致空压机因一级轴振动超标而停车。通过改造空压机导叶控制和将二、三级导叶开度固定在100%而彻底排除了故障,确保了空分设备安全、稳定运行。简介VK200-3型空压机结构,详细介绍停车故障的分析和处理过程。     

离心空压机节能降噪改造

由于威钢动力厂10000 m3/h空分设备配套的DA1200-42型空压机没有可靠的备用转子,一旦空压机现用转子发生故障,将会造成较大的间接经济损失;而且空压机运行能耗高、气流噪声很大。为保证空压机可靠运行和降低能耗,对空压机进行了节能降噪改造。简介空压机运行现状及运行中存在的问题,介绍改造方案以及具体实施过程和效果,对比分析了改造前后空压机的运行参数。     

空压机二级振动异常的原因分析与处理

介绍一起空压机二级振动异常的故障,分析了故障原因,通过安装空压机叶轮在线清洗系统解决了叶轮结垢问题,保证空压机安全运行。     

一起5TYD/160型空压机进水故障分析

在6500m3/h空分设备正常运行过程中,DCS系统服务器失电使电脑黑屏后程序出错,空压机放空卸压时空压机出口至空冷塔排气阀没有联锁关闭止逆阀,使空压机卸压放空时产生虹吸现象,造成空压机进水。简介故障发生过程,阐述故障原因的分析和采取的处理措施。     

酸素“5000”空分出力不足分析及改造

本文介绍5000m3/h空分设备运行中的故障判断分析,以及对板翅式换热器、空压机空气过滤系统和油系统的改造,并就在空压机出口补加空气等项措施进行了分析和探讨。     

DH-90型空压机油泵互投逻辑控制的完善

2#14000m3/h空分设备DH-90型空压机在切换油泵操作中,因互投逻辑问题出现多次故障,致使空压机联锁停车,分析故障原因,逐步修改并完善油泵互投逻辑控制,实现空压机稳定运行。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...