对国外一种氨制冷系统的改造

分析了将氨液分离器设计安装于低温冷库内的氨制冷系统的缺点，提出将氨液分离器及相关阀门搬迁至库外，改变热氨冲霜回液管设计的解决方法；并提供了氨液分离器安装高度的一种计算方法。     

液混式膨化硝铵炸药生产安全性研究

文章研究了液混式膨化硝铵炸药生产工艺的安全性。将86％-94％的氧化剂硝酸铵与可燃剂复合油相于100-125℃在液态状态下进行混合,得到悬浮状混合分散体系,再采用连续真空喷雾干燥工艺,脱除体系中的水分,制得了高性能粉状膨化硝铵炸药。该文讨论了液混式膨化硝铵炸药产品的组分相容性、机械感度、热感度和静电感度,分析了液混式工艺生产过程中的安全性,这对指导膨化硝铵炸药生产线的技术改造和安全生产,具有重要的现实意义。     

液混式膨化硝铵炸药生产技术研究

文章研究液混式生产工艺制备膨化硝铵炸药。将86%-94%的氧化剂硝酸铵与可燃剂复合油相于100-120℃,在液态状态下进行混合,得到悬浮状混合分散体系,再采用连续真空干燥工艺,脱除体系中的水分,制得了高性能膨化硝铵炸药。论文讨论了年产2万吨液混式膨化硝铵炸药生产线的工艺流程、设备设计和生产过程控制,这对指导生产线建设和生产过程产品质量控制具有重要的现实意义。     

Prediction of Transport Properties of Liquid Ammonia and Its Binary Mixture with Methanol by Molecular Simulation

Transport properties of ammonia and of the binary mixture ammonia + methanol are predicted for a broad range of liquid states by molecular dynamics (MD) simulation on the basis of rigid, non-polarizable molecular models of the united-atom type. These models were parameterized in preceding work using only experimental vapor-liquid equilibrium data. The self- and the Maxwell-Stefan (MS) diffusion coefficients as well as the shear viscosity are obtained by equilibrium MD and the Green-Kubo formalism. Non-equilibrium MD is used for the thermal conductivity. The transport properties of liquid ammonia are predicted for temperatures between 223 K and 473 K up to pressures of 200 MPa and are compared to experimental data and correlations thereof. Generally, good agreement is achieved. The predicted self-diffusion coefficient as well as the shear viscosity deviates on average by less than 15 % from the experiment and the thermal conductivity by less than 6 %. Furthermore, the self- and the MS transport diffusion coefficients as well as the shear viscosity of the liquid mixture ammonia + methanol are studied at different compositions and compared to the available experimental data.     

饱和液态制冷剂氨的热物理性质的分子动力学模拟

运用分子动力学方法模拟了制冷剂氨的饱和液态热物理性质。采用典型的site-site势能模型模拟了制冷剂氨的饱和液态密度和比焓,将模拟结果与美国国家标准研究所(NIST)数据库的值进行了对比,最大相对偏差分别在1.5%(密度)以内和3.2%(比焓)以内。对比结果表明:采用合理的势能模型和参数,运用该模拟方法预测单一组分工质的热物理性质是可行的。     

棉麻纤维液氨改性成套装备上下物料系统设计

目前棉麻纤维液氨改性系统的上下料采用人工方式进行,存在工作效率低、工人劳动强度大的缺点,基于发明问题解决理论(TRIZ)对液氨改性成套装备物料输送系统进行了创新设计,采用对心曲柄齿轮齿条机构和电磁铁来实现物料箱在小空间长行程的上下料,采用欧姆龙公司的CP1L型PLC来实现整个系统的控制,可实现棉麻纤维液氨改性成套装备物料包装输送系统的自动化。     

Equations for Thermal Conductivity of Natural Refrigerants

Experimental results for the thermal conductivity of ammonia, propane, butane, isobutane, and propylene are reviewed, with special attention given to the liquid phase. New equations for the thermal conductivity of these five substances applicable for practical use over wide ranges of temperature and pressure including the critical region are proposed based on the experimental data. The present equations as well as the existing equations are compared with the experimental data. Compared with existing equations for ammonia, isobutane, and propylene, which are not reliable in the liquid phase, the behavior of the thermal conductivity for these substances is much improved using the present equations.     

Synthesis and characterization of CuO nanoparticles from liquid ammonia

A new type of CuO nanoparticles were synthesized in liquid ammonia in the presence of sodium metal. First, Cu nanoparticles were obtained by reducing copper nitrate with the alkali metal in liquid ammonia, then, CuO nanoparticles were formed in the ambient conditions. The morphology and structure of as-prepared CuO nanoparticles were characterized by TEM and XRD, and the reason of aggregation of CuO nanoparticles was supposed.     

苎麻纤维改性研究进展

综述了苎麻纤维的改性原理以及苎麻纤维碱法、液氨、乙酰化、烷基化、磺化、氰乙基化、离子液体、阳离子、纳米粒子等改性工艺的最新进展,探讨了超临界流体苎麻纤维的改性.     

Optimal fan speed and compression ratio of an air-condensed vapor-compression ammonia recycling system

In the technology of liquid ammonia modification, the ammonia is recycled by compression and condensation. To minimize the energy-consumption of ammonia recycling system, compression ratio and fan speed are optimized. Thermodynamic models for the compressor and evaporative condenser are developed respectively. Mathematical equations are given to determine the optimal compression ratio and the corresponding fan speed ratio. To solve the equations, a numerical algorithm is proposed. By controlling the fan speed, the matching of ammonia mass flow rate and air flow rate can be optimized, which brings about the minimal energy-consumption. When the wet-bulb temperature is 22 °C, the system energy-consumption could be saved by 10.8–12.9% under optimal compression ratio and fan speed.     

氨制冷技术在天然气水合物中试中的特殊应用

本文具体分析了氨制冷技术在天然气水合物中试试验中的两个特殊应用:一是氨液分离器压力控制;二是氨压缩机出口热源应用.从实际运用看,效果良好.     

液氮洗冷箱的设计

液氮洗冷箱是合成氨的主要设备,是合成氨工艺的重要环节之一,由冷箱骨架、设备支架、阀架、管架、管道、平台梯子、设备(氮洗塔、板翅式换热器、分离罐等)、调节阀、仪表等组成.根据国内液氮洗冷箱工作压力的不同(2.0～3.0、5.0～6.0、7.0～8.0 MPa),出冷箱合成气总量主要是30万t/a和40万t/a.为提高液氮...     

制冷压力容器用材在液氨中应力腐蚀研究

本文通过慢应变速度应力腐蚀试验，研究制冷压力容器用材16MnR、Q235-C、20R三种材料焊接接头在液氨中的应力腐蚀行为，评定其在液氨中发生应力腐蚀开裂的敏感性。     

液氨泄漏范围影响因素的研究

液氨是一种常见的化工原料,由于具有腐蚀性且易挥发,通常储存于耐压储罐中。以液氨泄漏后几种事故情况中的毒气扩散为研究重点,运用ALOHA软件对立式储罐的泄漏情况进行模拟,对泄漏点的孔径大小和高度这两个因素展开分析,分别改变泄漏点的孔径和高度,结合数据和效果图中泄漏范围变化的趋势,比较泄漏结果。分析结果表明,氨气扩散范围随着泄漏点孔径的增大而增大,在孔径达到一定值后保持不变,并随泄漏点距地面高度的上升而降低。     

含有液体微胶囊的复合电沉积铜镀层性能的研究

研究了含有有机硅树脂为囊心的液体微胶囊复合镀铜层的性能.通过进行25%氨水溶液腐蚀试验、10%硝酸溶液腐蚀试验和耐磨试验,测定了这种复合镀层的耐蚀性和耐磨性.结果表明,由于复合镀铜层中含有液体微胶囊,其耐腐蚀性和耐磨性能都得到很大提高.     

Liquefied Sunshine: Transforming Renewables into Fertilizers and Energy Carriers with Electromaterials

It has become apparent that renewable energy sources are plentiful in many, often remote, parts of the world, such that storing and transporting that energy has become the key challenge. For long-distance transportation by pipeline and bulk tanker, a liquid form of energy carrier is ideal, focusing attention on liquid hydrogen and ammonia. Development of high-activity and selectivity electrocatalyst materials to produce these energy carriers by reductive electrochemistry has therefore become an important area of research. Here, recent developments and challenges in the field of electrocatalytic materials for these processes are discussed, including the hydrogen evolution reaction (HER), the oxygen evolution reaction (OER), and the nitrogen reduction reaction (NRR). Some of the mis-steps currently plaguing the nitrogen reduction to ammonia field are highlighted. The rapidly growing roles that in situ/operando and quantum chemical studies can play in new electromaterials discovery are also surveyed.     

Effect of solute mixing in the liquid propellant of a pulsed plasma thruster

Sodium chloride or ammonia was dissolved in the water propellant of pulsed plasma thrusters to improve the performance. Pulsed plasma thrusters using liquid propellant utilize water as attractive alternative instead of Teflon. Water propellant enables in controlling propellant mass flow and leads to high specific impulse. However, liquid propellant pulsed plasma thrusters have larger plasma resistance and lower thrust power ratio than the common Teflon propellant thruster. Here, sodium chloride and ammonia solution of water were examined to decrease that plasma resistance. As a result, emission lines attributed from the solute were observed using sodium chloride aqueous solution propellant, and a 5% reduction of the plasma resistance was shown, and the thrust to power was increased. However, ammonia aqueous solution decreased the thruster performance.     

制冷设备中Q345R制氨贮存容器须焊后热处理的原因探讨

分析了制冷设备中Q345R制氨贮存容器须焊后热处理的原因,并提出了防止液氨压力容器应力腐蚀开裂的措施。     

Viscosity Measurements of Ammonia, R32, and R134a. Vapor Buoyancy and Radial Acceleration in Capillary Viscometers

The saturated liquid viscosity of ammonia (NH₃) and of the hydrofluorocarbons, difluoromethane (CH₂F₂, R32) and 1,1,1,2-tetrafluoroethane (CF₃–CH₂F, R134a), was measured in a sealed gravitational viscometer with a straight vertical capillary. The combined temperature range was from 250 to 350 K. The estimated uncertainty of the ammonia measurements is ±3.3 and ±2 to 2.4% for the hydrofluorocarbons with a coverage factor of two. The results are compared with literature data which have been measured with capillary viscometers of different design. Agreement within the combined experimental uncertainty is achieved when some of the literature data sets are corrected for the vapor buoyancy effect and when a revised radial acceleration correction is applied to data which were obtained in viscometers with coiled capillaries. An improved correction for the radial acceleration is proposed. It is necessary to extend inter-national viscometry standards to sealed gravitational capillary instruments because the apparent inconsistencies between refrigerant viscosity data from different laboratories cannot be explained by contaminated samples.     

Fundamental principles for sizing and design of gravity separators for industrial refrigeration

Throughout the past decades, the industrial refrigeration industry has developed various “rule of thumb” methods for sizing gravity liquid separators for ammonia and other common refrigerants. However, to date a uniform systematic approach or an agreeable standard has not been established. For commonly used refrigerants such as ammonia, the large installed base of separators can be used as a benchmark for sizing separators. But, when using a less common refrigerant such as CO₂, the designer faces new challenges. In this paper, a systematic approach is presented for sizing horizontal and vertical gravity liquid separators for industrial refrigeration applications. To compute separation velocities and separation distances, a theoretical model is presented. The model is used as a basis for comparison with observations from 85 operating gravity separators surveyed in the field. Criteria and formulas are presented for estimating the required liquid volume for storage. An example is provided demonstrating the use of the methods presented in this paper.