变频调节技术对空压机能耗的影响

介绍了变频调节技术对空压机机组输入比功率(能耗)的影响,通过试验数据分析了用气量占空压机额定排气量不同比例时,变频调节技术与容调阀调节、加卸载调节技术的能耗情况,体现变频调节技术的节能效果。     

关于丙烷制冷螺杆压缩机V_i值设定的探讨

天然气处理厂丙烷制冷系统是影响整个工艺装置的丙烷收率的重要系统,系统中额定功率298kW的丙烷制冷螺杆压缩机是全厂设备中能耗最大的用电设备。工况、气体处理量、操作等众多因素均有可能影响压缩机能耗,从丙烷制冷螺杆压缩机Vi值(内容积比)的角度来探讨机组的经济运行。     

PBT/纳米高分子复合材料微细发泡注射成型机械和热性能探讨

主要研究聚丁烯对苯二甲酸酯(Polybutylene Terephthalate,PBT)/纳米黏土复合材料的传统注塑成型,以及以氮气(N2)作为发泡剂的微孔注射成型的加工质量。考虑了纳米颗粒尺寸、纳米材料含量、混炼螺杆转速对制品机械性能与热性能的影响。PBT/纳米黏土复合材料用双螺杆挤出机混炼方式制备,试片依据ASTM D638和D256标准进行了测试。根据实验结果,发现:传统注塑制品的拉伸强度,35μm纳米颗粒结果大于8μm的,且混炼中螺杆转速快,抗拉强度有升高的趋势。抗拉强度从纳米比例0~1.0%(wt)随着纳米比例含量增加而增强的趋势,纳米比例含量超过1.0%后,抗拉强度就有下降的趋势。通过热性能实验,发现加入适量的纳米黏土确能提高材料的热稳定性与结晶度,但是过量的黏土反而造成性能下降,与力学性能实验结果吻合。     

三螺杆动态混炼挤出HDPE/Mg(OH)_2填充体系的力学性能

从加工工艺和设备改进入手改善Mg(OH)2在高密度聚乙烯(HDPE)中的分散性。将电磁振动技术和三螺杆挤出机结合起来,用三螺杆动态混炼挤出机挤出HDPE/Mg(OH)2,通过对挤出物料中Mg(OH)2的分散性研究,得出三螺杆动态混炼对Mg(OH)2的分散性和HDPE/Mg(OH)2力学性能的影响规律,并对在不同振动参数(振幅、频率)下制取标准力学性能测试试样与稳态挤出时试样力学性能的比较获取最优的振动参数范围,解决了因Mg(OH)2填充量过高而严重影响复合材料力学性能的问题。     

混炼参数对短纤维-橡胶复合材料性能的影响

混炼参数是短纤维-橡胶复合材料制备过程中重要的工艺参数,直接影响着短纤维的补强性能。通过实验对比分析了填充系数、上顶栓压力、冷却水温度、转子转速和短纤维添加份数5个混炼参数对短纤维-橡胶复合材料混炼过程和硫化胶物理机械性能的影响。结果表明随着填充系数、上顶栓压力等参数的增加,混炼过程中消耗的最大功率、单位能耗等不断增加,而硫化胶的物理机械性能则有最佳值。当填充系数为0.6,上顶栓压力为0.6MPa,冷却水温度为40℃,转子转速为70r/min,短纤维添加份数为3份时,短纤维-橡胶复合材料的物理机械性能最佳。     

动态塑化混炼技术对PP/硅灰石力学性能影响的研究

以硅灰石填充聚丙烯作为研究对象,经三螺杆动态塑化混炼加工后制成试样并进行SEM断面分析和力学性能测试.研究了在不同振动参数条件下对PP/硅灰石力学性能的影响.研究表明:与稳态相比,动态(引入振动力场后)加工条件下试样的冲击强度、拉伸强度、断裂伸长率和弯曲强度都有显著的提高.     

动态塑化混炼技术对PP/硅灰石力学性能影响的研究EI

以硅灰石填充聚丙烯作为研究对象,经三螺杆动态塑化混炼加工后制成试样并进行SEM断面分析和力学性能测试.研究了在不同振动参数条件下对PP/硅灰石力学性能的影响.研究表明:与稳态相比,动态(引入振动力场后)加工条件下试样的冲击强度、拉伸强度、断裂伸长率和弯曲强度都有显著的提高.     

封闭通道后数据中心的PUE分析

封闭通道是解决数据中心中高热密度机柜冷却问题的有效办法。封闭冷通道后室内风机送风量可减少30％,室内风机可省电约2／3,封闭热通道后室内风机送风量可减少12．5％,室内风机可省电约1／3;封闭冷通道后制冷系统的能耗在数据中心整体能耗中所占比例由38％减为35．4％,封闭热通道后制冷系统的能耗在数据中心整体能耗中所占比例由38％减低为36．7％;数据中心封闭冷通道比封闭热通道节能2％,比不封闭通道节能4％。一个典型的数据中心的PUE计算实例表明：封闭冷通道后数据中心的PUE值降低0．04,封闭热通道后数据中心的PUE值降低0.02。     

螺旋盘端面混炼挤出机混炼效果的理论研究

通过对螺旋盘式端面同机进行建模和计算机数值分析,研究了螺盘槽深、槽宽和螺盘转速对混炼过程的均匀程度和分散程度的影响,从而对合理设计混炼主选择工艺参数提供依据。     

阻尼板材干法混炼工艺研究

采用干法混炼工艺生产阻尼板材，研究了加工设备、温度、时间、投料顺序对产品性能的影响。实验证明，干法混炼工艺比乳液法生产具有操作简便、过程简单、生产成本低等优点。     

Concrete Mixing Methods and Concrete Mixers: State of the Art

As for all materials, the performance of concrete is determined by its microstructure. Its microstructure is determined by its composition, its curing conditions, and also by the mixing method and mixer conditions used to process the concrete. This paper gives an overview of the various types of mixing methods and concrete mixers commercially available used by the concrete industry. There are two main types of mixers used: batch mixers and continuous mixers. Batch mixers are the most common. To determine the mixing method best suited for a specific application, factors to be considered include: location of the construction site (distance from the batching plant), the amount of concrete needed, the construction schedule (volume of concrete needed per hour), and the cost. Ultimately, the quality of the concrete produced determines its performance after placement. An important measure of the quality is the homogeneity of the material after mixing. This paper will review mixing methods in regards to the quality of the concrete produced. Some procedures used to determine the effectiveness of the mixing will be examined.     

Modelling and simulation of energy consumption of ceramic production chains with mixed flows using hybrid Petri nets

Ceramic production chain consisting of discrete flow and continuous flow energy-intensive processes consumes substantial amounts of energy. This study aims to evaluate energy consumption performance and energy-saving potentials of the ceramic production chain. According to the energy consumption characteristics of manufacturing processes and process interaction constraints in a ceramic production chain, an approach integrating the first-order hybrid Petri net (FOHPN) model, an objective linear programming model and a sensitivity analysis is proposed. The FOHPN model will simulate the energy consumption patterns of the ceramic production chain. Meanwhile, multi-objective linear programming model and sensitivity analysis will suggest the optimal specific energy consumption (SEC) of the production chain and identify the influences of input parameters (i.e. production rate of a process) on the SEC in the optimal production scheme. Finally, a real case study from bathroom ceramic plant validates the approach. It provides a tool for modelling and simulation of energy consumption of ceramic production chains with mixed flows and helps operators to perform energy-saving actions in the ceramic enterprise.     

从设计原理及运行工况特性分析置换通风的节能

通过对置换通风设计原理及运行状况特性的分析,比较了置换通风和混合通风的能耗,认为置换通风在整体上是节能的.     

Experimental technique to analyze the influence of cutting conditions on specific energy consumption during abrasive metal cutting with thin discs

Specific energy consumption is an important indicator for a better understanding of the machinability of materials. The present study aims to estimate the specific energy consumption for abrasive metal cutting with ultra-thin discs at comparatively low and medium feed rates. Using an experimental technique, the cutting power was measured at four predefined feed rates for S235JR, intermetallic Fe-Al(40%), and C45K with different thermal treatments. The variation in the specific energy consumption with the material removal rate was analyzed through an empirical model, which enabled us to distinguish three phenomena of energy dissipation during material removal. The thermal treatment and mechanical properties of materials have a significant impact on the energy consumption pattern, its corresponding components, and cutting power. Ductile materials consume more specific cutting energy than brittle materials. The specific cutting energy is the minimum energy required to remove the material, and plowing energy is found to be the most significant phenomenon of energy dissipation.The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00361-2     

氢液化流程设计和优化方法研究进展

随着全球能源消耗和环保形势日益严峻,氢能利用逐年增加,而氢低温液化是一个流程复杂、能耗高、效率较低的低温热力学过程,降低氢液化过程的能耗以及提高流程效率是研究的目标。本文总结了近年来氢液化流程设计和优化的研究进展,介绍并对比了预冷氢液化流程和级联氢液化流程,讨论了这些流程的单位能耗、火用效率和性能系数,并对核心设备进行了简单介绍,总结了文献中的氢液化流程的最新技术发展及未来的发展方向。     

Three‐dimensional viscous flow over rotating periodic structures

The three‐dimensional Stokes flow in a periodic domain is examined in this study. The problem corresponds closely to the flow inside internal mixers, where the flow is driven by the movement of a rotating screw; the outer barrel remaining at rest. A hybrid spectral/finite‐difference approach is proposed for the general expansion of the flow field and the solution of the expansion coefficients. The method is used to determine the flow field between the screw and barrel. The regions of elongation and shear are closely examined. These are the two mechanisms responsible for mixing. Besides its practical importance, the study also allows the assessment of the validity of the various assumptions usually adopted in mixing and lubrication problems. Copyright © 2003 John Wiley & Sons, Ltd.     

消费领域用能特征探究

根据使用过程特征,可以将用能行为分成生产领域用能与消费领域用能。前者提供产品,后者提供服务。消费领域与生产领域用能存在不同特征,其评价方法、节能途径、战略政策等也存在差别。考虑到这一领域能耗可能是我国下一阶段能耗增长点,在节能领域需要对其给予足够的重视。本文在分析消费领域用能特征的基础上,提出对其的衡量方式和节能途径,并针对我国目前消费领域用能的现状给出建议。     

Design and modelling of a self-dispersing twisted pipe to mitigate settling in coal water suspension

The hydrotransport of the industrial powders and bulk solids such as minerals, mineral tailings, coal and ash is considered to be an efficient mode of transportation. The pipelines ranging from a few meters to few kilometers in length are used for such transportation purposes. If not well addressed, the issue of particle settling in such pipelines can lead to blockage and even bursting of the pipeline due to the continued deposition of the solids. The present study proposes the introduction of a twisted pipe section of a suitable length and geometry, that produces enough turbulence in the flow, sufficient for the re-dispersion of the already settled particles and check their further deposition. To achieve this objective, 5 different geometries (each having 4 different lengths) of twisted pipes are designed and used to model the dynamics of the particles’ flow through them and in their downstream region. A low influx velocity (where particle settling is expected) of 0.5 m/s is selected for all the cases and the influx solids’ mass concentration ranges from 40 to 60%. The results generated by the commercial CFD software are in good agreement with the experimental data. The parameters viz. mixing index, pressure loss, and specific energy consumption are evaluated to choose the best design of the twisted pipe section. The 0.2 m long 3 lobes twisted pipe section is found to deliver the suspension of highest homogeneity at the cost of a slight increase in pressure loss and specific energy consumption. The present solution ensures the mitigation of particles’ settling and the other related issues.     

膨化硝酸铵炸药连续碾混系统的设计和应用

经过对多种可能混合途径的分析和比较,论述了以卧式连续碾混机和随动定量配料系统为基本技术的混合系统的设计、结构和应用,获得了膨化硝铵炸药连续混合新工艺,形成了稳定的工业化生产的规模和能力.     

Green polypropylene/waste paper composites with superior modulus and crystallization behavior: Optimizing specific energy in solid-state shear pulverization for filler size reduction and dispersion

Solid-state shear pulverization (SSSP) is a continuous process that overcomes challenges in producing well-dispersed polymer composites that cannot be made by twin-screw melt extrusion. We use SSSP to produce 85/15 wt% polypropylene/waste paper biocomposites with polypropylene pellets and 2-cm-square waste paper pieces as starting material. Single-pass SSSP achieves effective filler size reduction and dispersion within the polypropylene matrix. We determine how waste paper size reduction and composite properties are functions of specific energy input and tune specific energy input by SSSP screw design and throughput. Composites made at moderate to high specific energy input (14–35 kJ/g) have 25 to nearly 50% of filler particles at sub-micron size; relative to neat polypropylene, composites exhibit a 70% increase in Young’s modulus, retention of neat polypropylene yield strength, and a ∼50% reduction in crystallization half-time. Estimates indicate that the cost of such biocomposite materials made by SSSP is less than that of virgin polypropylene.