60000m~3/h空分设备快速变工况生产的操作探讨与实践

为降低60000m~3/h空分设备的氧气放散率,武钢氧气公司实施了空分设备的手动快速变工况生产。分析了空分设备运行工况不稳定和自动变工况系统难以实施的原因,介绍了手动快速变工况的理论依据、前期准备工作和实施过程,阐述了手动快速变工况实施进程中应注意的事项。     

空分设备手动变负荷失败的分析与处理

介绍30000 m3/h空分设备手动变负荷操作时出现失误后的运行工况变化情况和原因,阐述正确的手动变负荷操作步骤,最后总结为使空分设备运行工况恢复正常而采取的措施。     

减少钢铁企业氧气放散量的措施总结

针对钢铁企业空分设备氧气放散量大的情况,从空分设备流程的选择、加装液化装置、向主冷返充液体、变工况操作以及液体直接汽化等方面,分析了减少氧气放散量的措施和可行性,以达到空分设备经济运行的目的。     

空分设备变负荷调节主要参数的关系及计算

提高空分设备变负荷调节能力是解决钢铁企业氧气放散率高的主要措施之一．以KDON-18000／18000型空分设备为例，对变更空气量的变负荷调节进行了理论推演和试验研究．得出了变更空气量负荷变化时，空分设备各主要参数（空气量、氧气量、粗氩流量、膨胀空气量、膨胀空气旁通量、氩馏分量、空压机排气压力和下塔阻力等）的变化规律，建立了部分变负荷时的数学模型及试验关联式。根据关联式和数学模型，对空分设备在73％～106％负荷间的12个工况进行了各主要参数计算。对空分设备各部机进行综合分析，空分设备的综合变负荷能力比各单机要小。     

15000m~3/h内压缩流程空分设备手动变负荷调节实践

简介柳钢15000m~3/h内压缩流程空分设备的流程,介绍手动变负荷调节的实施情况,分析影响手动变负荷调节范围的因素,从保持氩馏分组分含量稳定、控制中抽气体温度和快速操作三方面详细叙述了手动变负荷调节的操作要点。     

6000m~3/h空分设备经济运行的实施

为实现6000m3/h空分设备节能降耗的目标,制定了具体的工况调整措施:精细化操作,保证空分设备在最佳状态下运行;严格按照调度指令进行变工况调整;氧气供需量不均衡时,进行变工况调整。取得了较好的经济效益。     

3~#23500m~3/h空分设备增产氧气操作实践

介绍空分设备由标准工况转变到最大氧气工况的操作过程、操作依据和注意事项,考核了空分设备的生产能力、精馏潜力和氧压机压氧能力。通过操作实践,进一步熟悉了机组性能,并为其他变工况操作积累了操作经验。     

气液联产空分设备放空气氧回流循环的工艺优化

气态氧的存储量受限于氧气管网,当管网压力达到上限后,虽由氧气球罐储存和变工况生产来降低氧气放散量,但还是有大量气氧被迫排空,降低了空分设备的有效产量,增加了运行成本。为减少气氧放空量,实施了放空气氧回流循环的工艺优化。简介KDON-500Y(500)/460Y型空分设备精馏系统的工艺流程,阐述放空气氧回流循环流程的设计、施工及实施效果。     

首钢新建35000m^3／h空分设备的流程及特点

简介了首钢氧气厂新建35000m^3／h空分设备的工艺流程及技术参数，详细分析了常规变负荷和快速变负荷调节时空分设备的运行工况以及快速变负荷调节时的工艺特点。     

空分设备变负荷调节主要参数的关系及计算

提高空分设备变负荷调节能力是解决钢铁企业氧气放散率高的主要措施之一,以KDON-18000/18000型空分设备为例,对变更空气量的变负荷调节进行了理论推演和试验研究,得出了变更空气量负荷变化时,空分设备各主要参数(空气量、氧气量、粗氩流量、膨胀空气量、膨胀空气旁通量、氩馏分量、空压机排气压力和下塔阻力等)的变化规律,建立了部分变负荷时的数学模型及试验关联式。根据关联式和数学模型,对空分设备在73%~106%负荷间的12个工况进行了各主要参数计算。对空分设备各部机进行综合分析,空分设备的综合变负荷能力比各单机要小。     

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.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

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.……     

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.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

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.……     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.