Comparative evaluation of energy and resource consumption for vacuum carbothermal reduction and Pidgeon process used in magnesium production

With the fast development of the application of magnesium based alloys,the demand for primary magnesium is increasing dramatically all over the world.The Pidgeon process is the most widely used process for producing magnesium in China,but suffers from problems such as high energy,resource consumption and environmental pollution.While the process of vacuum carbothermal reduction to produce magnesium(VCTRM)has attracted more and more attention as its advantages,but it has not been well-practiced in industrial applications and there also is no comprehensive and quantitative analysis of this process.This study quantified the flows of resource and energy for the Pidgeon process and the VCTRM process,then compared and analyzed these two processes with each other from three aspects.The VCTRM process results in 63.14%and 69.16%lower of non-renewable mineral resources and energy consumptions when compared to the Pidgeon process,respectively.Moreover,the low energy consumption(2.675 tce vs.8.681 tce)and material to magnesium ratio(2.953:1 vs.6.429:1)of the VCTRM process,which lead to lower greenhouse gas(GHG)emissions(8.777 t vs.26.337 t)and solid waste generation(0.522 t vs.5.465 t)with a decrease of 66.67%and 90.45%,respectively.Results indicate that the VCTRM process is a more environmentally friendly process for magnesium production with high efficiency but low cost and low pollution,and it shows a good potential to be industrialized in the future after solving the bottleneck problem of the reverse reaction.

Optimized algorithm in mine production planning, mined material destination, and ultimate pit limit

An integral connection exists among the mine production planning, the mined material destination, and the ultimate pit limit （UPL） in the mining engineering economy. This relation is reinforced by real information and the benefits it engenders in the mining economy. Hence, it is important to create optimizing algorithms to reduce the errors of economic calculations. In this work, a logical mathematical algorithm that considers the important designing parameters and the mining economy is proposed. This algorithm creates an optimizing repetitive process among different designing constituents and directs them into the maximum amount of the mine economical parameters. This process will produce the highest amount of ores and the highest degree of safety. The modeling produces a new relation between the concept of the cutoff grade, mine designing, and mine planning, and it provides the maximum benefit by calculating the destination of the ores. The proposed algorithm is evaluated in a real case study. The results show that the net present value of the mine production is increased by 3% compared to previous methods of production design and UPL.

A novel process integrating vacuum distillation with atmospheric chlorination reaction for flexible production of tetrachloroethane and pentachloroethane

In this paper, we developed a novel process integrating vacuum distillation with atmospheric chlorination reaction(VD-ACR) to realize the flexible production of tetrachloroethane(TeCA) and pentachloroethane(PCA)from 1,2-dichloroethane(DCA). During the simulation, the distillation column and reactors were operated for separation and chlorination respectively under variable pressures and temperatures. It is interesting to note that VD-ACR processes producing pure TeCA or PCA can exhibit the similar configuration parameters after optimization, which enables the flexible production of TeCA and PCA with different molar ratios via changing operating parameters. The molar ratio of TeC A/PCA can be fine-tuned within the range of 0.9:0.1-0.1:0.9 through adjusting the amount of chlorine pumped into side reactors, giving rise to the increase of the heat duty of reboiler by five times. A pilot-scale experiment was then operated based-upon this VD-ACR process and the result matched well with the simulation. Therefore, the VD-ACR model presented in this study will be beneficial for the industrial-scale flexible production of TeCA and PCA from DCA.

Electron-positron pair production in ultrastrong laser fields

Electronepositron pair production due to the decay of vacuum in ultrastrong laser fields is an interesting topic which is revived recently because of the rapid development of current laser technology.The theoretical and numerical research progress of this challenging topic is reviewed.Many new findings are presented by different approaches such as the worldline instantons,the S-matrix theory,the kinetic method by solving the quantum Vlasov equation or/and the real-time DiraceHeisenbergeWigner formalism,the computational quantum field theory by solving the Dirac equation and so on.In particular,the effects of electric field polarizations on pair production are unveiled with different patterns of created momentum spectra.The effects of polarizations on the number density of created particles and the nonperturbative signatures of multiphoton process are also presented.The competitive interplay between the multiphoton process and nonperturbation process plays a key role in these new findings.These newly discovered phenomena are valuable to deepen the understanding of pair production in complex fields and even have an implication to the study of strong-field ionization.More recent studies on the pair production in complex fields as well as beyond laser fields are briefly presented in the view point of perspective future.

Development and Application of a Production Data Analysis Model for a Shale Gas Production Well

This paper presents the development and application of a production data analysis software that can analyze and forecast the production performance and reservoir properties of shale gas wells.The theories used in the study were based on the analytical and empirical approaches.Its reliability has been confirmed through comparisons with a commercial software.Using transient data relating to multi-stage hydraulic fractured horizontal wells,it was confirmed that the accuracy of the modified hyperbolic method showed an error of approximately 4%compared to the actual estimated ultimate recovery(EUR).On the basis of the developed model,reliable productivity forecasts have been obtained by analyzing field production data relating to wells in Canada.The EUR was computed as 9.6 Bcf using the modified hyperbolic method.Employing the Pow Law Exponential method,the EUR would be 9.4 Bcf.The models developed in this study will allow in the future integration of new analytical and empirical theories in a relatively readily than commercial models.

Acetylene Vacuum Carburizing

Almost 30 years has passed since the publication of materials on vacuum carburizing technology, and is attracting a great deal of attention as a technology capable of being used as a substitute for gas carburizing technology. However, the technology was not popular except in specific fields. The main reason for this is due to a variety of harmful influences accompanying the sooting problems caused by CH4 or C3H8. We have succeeded in that the occurrence of sooting was suppressed by utilizing acetylene, at extremely low pressure for carburizing (below 1 kPa). This process is now showing the excellent quality and prospects for this technology in terms of quality, economy and safety. At present almost 70 practical mass production furnaces are used in production lines, in Japan and abroad. At this time, we will report summary of the present acetylene vacuum carburizing process and the actual results obtained by these acetylene vacuum carburizing furnaces for mass production.

Effect of microwave-vacuum drying(MVD)method on quality properties of agro-products

Microwave-vacuum drying is an accepted drying method for agro-products, which is nonetheless still relatively unknown to some. This paper attempted to give an overview of the most important aspects of microwaves-vacuum drying （MVD） and their relevance to agro-products processing. Some advantages on microwave-vacuum drying properties were discussed to provide a better insight into the reasons for the use of microwaves. Also the effects of the MVD on the quality of several agro-products and reasonable processing parameters were given, which develop the guidance to the application of MVD on the agro-products dehydration. As a potential drying technology, MVD will be broadly utilized for the other agro-products processing

Production of Dissimilar Metals Materials by the Method of Solid-State Joining

Mechanisms taking place while hot rolling in vacuum of dissimilar materials joined in solid phase are described. It is shown that at joining of materials in solid phase redistribution of atoms from one material into another occurs on the interface of joining. On the base of calculation and experimental results it is concluded that the ultimate strength of the interface of joint is always higher than the ultimate strength of less durable material. Pair zirconium-stainless steel SS (Type AISI 321) and carbon steel (Type C22E) those are used in nuclear power are investigated.

不同真空包装材料对酱肉产品理化及微生物性质的影响

为研究不同包装材料对酱肉贮藏期间品质的影响,以聚酯/铝/聚乙烯(PET/AL/PE)铝箔和聚酯/聚乙烯(PET/PE)透明薄膜为包装材料,对四川酱肉进行真空包装,测定酱肉在常温贮藏过程中水分活度、过氧化值、丙二醛含量、pH值、亚硝酸盐含量、色泽、质构特性及菌落总数的变化。结果表明,真空铝箔包装相较于真空透明包装可延缓酱肉脂质的氧化并加快亚硝酸盐的降解,对维持酱肉的硬度、弹性、咀嚼性和内聚性有显著效果,并对抑制微生物的繁殖有显著作用。

无损可动态监测的铁质文物真空脱盐装置设计及应用

设计并制作了一套无损可动态监测铁质文物的真空脱盐装置,采用去离子水为脱盐溶液,通过脱盐溶液电导率、氯离子含量动态监测其脱盐效率,同时通过对比铁质文物脱盐前后的外观、质量和表面组分变化,评价脱盐效果。结果表明:采用该装置进行脱盐可大幅度提升脱盐效率,溶出的氯离子主要为游离态,脱盐2 h时脱盐溶液中氯离子质量浓度达到88.11 mg/L,相当于同条件下浸泡脱盐法的5.32倍;在本试验条件下,真空脱盐法所得氯离子溶出总量始终大于浸泡脱盐法,真空脱盐第1轮的氯离子溶出量达798.94 mg,相当于浸泡脱盐法的3.18倍。同时,该真空脱盐装置不仅不会对铁质文物造成额外伤害,还可有效避免铁质文物在脱盐过程中的氧化。

大黄鱼鱼卵腌制品贮藏过程中的品质变化规律

为探究大黄鱼鱼卵腌制品贮藏过程中的品质变化规律,以大黄鱼鱼卵腌制品为研究对象,研究不同贮藏温度(5、25℃)以及包装方式(普通包装、真空包装)对大黄鱼鱼卵腌制品挥发性盐基氮(total volatile basic nitrogen,TVB-N)值、过氧化值(peroxide value,POV)、菌落总数、水分含量、汁液流失率、pH值、硬度、弹性和b*值的影响,并进行感官评价。结果表明,5℃真空包装可以显著抑制贮藏期间大黄鱼鱼卵腌制品TVB-N值、POV、菌落总数、水分含量和汁液流失率的增加,同时延缓大黄鱼鱼卵腌制品硬度和弹性的降低,并保持较高的感官评分,有利于保持大黄鱼鱼卵腌制品的质构特性和感官品质,但对pH值和b*值的影响不显著。

微波真空膨化加工等外枣工艺优化

以传统晾晒干制的等外枣作为原料,复水枣经过预干燥进行微波真空膨化加工。通过微波功率、微波时间、抽真空时间3个单因素试验筛选工艺参数条件,以膨化度、含水率、硬度和感官评分为考察指标,在单因素试验的基础上进行响应面试验,优化微波真空膨化等外枣的工艺条件。最佳膨化工艺条件为微波功率360 W、微波时间3.2 min、抽真空时间3.1 min,在此条件下膨化产品膨化度(151.25±2.15)%,含水率(3.524±0.856)%,硬度(2859.26±52.36)g。通过优化工艺的该膨化产品具有较高的膨化度,较低的含水率和适中的硬度。

白萝卜脆片真空油炸工艺研究

白萝卜富含多种营养成分,是贵州省主栽的冷凉蔬菜作物。以白萝卜为原料,通过单因素试验和正交试验研究切片厚度、油炸温度、油炸时间和离心时间等因素对白萝卜脆片质量的影响,确定真空油炸白萝卜脆片的最优生产工艺。结果表明,白萝卜脆片生产的最佳工艺条件为切片厚度6 mm、油炸温度90℃、油炸时间20 min、离心时间5 min。

机械蒸汽再压缩耦合中空纤维真空膜蒸馏系统试验

为了解决工业废水处理过程中分离效率低、运行能耗高的问题,设计搭建了一套新型的机械蒸汽再压缩(MVR)耦合中空纤维真空膜蒸馏系统,考察了耦合系统的运行特性,并开展了不同进料条件及长时间运行下系统对氯化铵溶液蒸发的试验研究。结果表明,当进料液氯化铵质量分数、进料液温度、进料液流量和真空侧压力分别为5%、75℃、10 m^(3)/h和24 kPa时,产水速率和产水电导率基本稳定在45.9 kg/h和11.9μS/cm,分离效率为99.9%,单位加热能耗(SHEC)为118.5 kW·h/t。随着进料液氯化铵质量分数的增加,产水速率减小,SHEC增加;而随着进料液温度和进料液流量增加,产水速率增加,SHEC减小。经过240 h运行试验,膜污染并未明显影响产水水质,但降低了产水速率,经膜清洗后,产水速率可恢复至原来的96.1%,该系统能够高效分离氯化铵溶液,回收能源,应用前景非常广阔。

面向批产化遥感卫星的热控系统研制优化与实践

文章针对批产化遥感卫星研制要求,探索了热控系统的优化策略,应用于“吉林一号”某批产卫星的研制过程。相较单星侧重于目标可行性验证的研制流程,批产卫星的研制重点为更低成本、更高效率的生产。文章遵循结构-热控一体化的思路,进行了低外热流敏感性、低控温功耗、低材料成本的热控设计;依托脉动式AIT生产线及自动化生产设备,细化热控实施流程,缩短准备工作时长,灵活安排人员工位,大幅提升卫星生产效率;依据批产卫星的热控设计特点及试验需求,采用基于等效热沉的外热流模拟方法,降低了真空热试验的复杂性。当前该型号批产遥感卫星已生产并发射54颗,卫星在轨状态良好,该热控批产化研制思路可为其他批产卫星的研制提供有效参考。

真空自耗电弧炉防爆设计与安全生产研究

真空自耗电弧炉是钛及钛合金制备的主要设备,但在熔炼过程中存在严重的爆炸风险。该文对钛及钛合金真空自耗熔炼爆炸机理进行研究,简要分析引发爆炸的几种情况,通过对爆炸威力的计算,研究包括水冷结晶器、真空熔炼室、X-Y调节机构等在内的设备主体方面,以及包括防爆墙、泄爆口和防爆门等在内的设备基础方面的防爆设计,在操作系统中设置防爆预警,并针对防范重点提出相应的安全生产建议措施,避免熔炼爆炸事故的发生。

基于沥青产品性质预测的全局资源优化模型研究

全局资源优化模型通常采用线性规划模型搭配二次非线性模块的数学模型表征炼油厂加工流程,能解决全厂超多变量最优化问题。优化模型中的常减压模块通常采用线性收率并固定原油品种,以约束各加工线路。模型表达能力有限,对于渣油组分生成沥青产品的优化能力较差,测算方案难以准确执行,无法做到全局资源最优化计算。该研究提出了一种针对沥青生产的建模优化方式:使用沥青生产数据训练线性回归模型表征沥青产品关键指标性质,并集成到资源优化模型中,转化为二次非线性约束项,实现全局优化。研究结果能帮助企业更精准地测算最佳原油调合配方以生产合格沥青产品,并完善渣油组分效益比较测算方式。采用该建模优化方式对某炼油企业进行了测算,结果表明,采用该研究中的沥青调合建模方法能进一步优化企业的原油资源配置,保证沥青产品质量。

冻干白茶甜橙块配方研究

【目的】目前,白茶主要以冲泡饮用为主,市场上可供选择的白茶食品有限。本研究以速溶白茶粉和甜橙为主要原料,研制一款具有独特风味的新型白茶食品。【方法】通过单因素实验和正交试验,结合感官评分考察了速溶白茶粉、甜橙果酱和甜橙香精对冻干白茶甜橙块感官品质的影响,优化了冻干白茶甜橙块的配方。【结果】冻干白茶甜橙块的最佳工艺配方为速溶白茶粉0.1 g、甜橙果酱5 g、甜橙香精0.5 g、冰糖5 g、白砂糖5 g、糊精5 g、果胶0.5 g和水72 g。【结论】在此配方条件下可制得茶香、橙香和柚香浓郁协调,酸甜可口的冻干白茶甜橙块。

微波真空干燥在农产品加工中的研究现状

干燥是食品工业中最古老的保鲜技术之一。微波真空干燥是一种结合微波和真空技术的先进干燥方法。近年来,微波真空干燥在提高农产品质量、减少能源消耗和保留营养成分方面取得了显著的研究进展。通过对相关文献的综述,深入探讨了微波真空干燥在农产品加工中的研究现状,包括技术原理、优势、应用领域以及存在的挑战与前景,可为农产品微波真空干燥的产业推广和理论研究提供依据。

制盐多效蒸发真空节能技术探讨与应用

多效蒸发制盐工艺中末效的真空度直接影响各效蒸发压力和温度,进而影响传热效率、二次蒸汽的冷凝和不凝气的排除,对产量和能耗造成影响。因此,提高末效真空系统效率对多效真空制盐的节能提效至关重要。本文通过对多效蒸发制盐过程的工作能力及真空度进行研究,得到实现末效真空及整个制盐过程节能降耗的指导思路,据此研究探讨一种多管喷射真空节能技术,供有相似情况的生产单位交流探讨。