间歇法氯乙酸生产技术改造

针对间歇法氯乙酸生产装置存在的问题,对氯化工艺、结晶系统、尾气吸收系统、空气净化及真空系统进行了技术改造。改造后,提高了氯乙酸的质量及产量,降低了生产成本,并改善了操作环境。     

盛元聚酯380 t/d扩容技改

针对盛元聚酯厂运行的实际情况,剖析了300 t/d单线聚酯生产装置进一步提产存在的问题,提出技术改造方案。主要通过在线更换或增加配料系统、输送系统等部分关键设备,并对真空系统进行改造,调整生产工艺参数,从而使产能由300 t/d提高到380 t/d。改造后的设备运行稳定,大幅度降低了生产成本,产品品质达到增容前的水平,取得了明显的经济效益。     

真空干燥釜的改进

针对真空干燥釜产品干燥后水分超标的问题,结合真空干燥釜的工作原理,分析产品干燥不合格的原因,并提出技术改造措施。改造后,达到了预期的干燥效果。     

间歇聚合试验反应釜热媒系统及真空管线改造

为适应工艺试验需要,针对研究院中试装置PU150和PU300两套间歇聚合反应釜的热媒系统进行技术改造,对新增热媒系统做校核计算,同时对真空系统管线进行了局部调整改造。     

湿法磷酸装置工艺优化改造

介绍青海云天化国际化肥有限公司针对120 kt/a湿法磷酸装置在运行过程中存在的问题,对循环水冷却塔、磷酸浓缩真空系统、反应闪冷系统进行的一系列优化技术改造,改造后节能降耗的效果明显,总节能效益达到852.8万元。     

缩聚真空喷淋水的改造

剖析了裕华聚酯切片三厂缩聚真空喷淋水系统存在的问题,提出了技术改造方案,方案在系统上实施后效果明显。实践证明,该技术改造是成功的,同时为其它同类装置的技术改造提供了借鉴的经验。     

聚酯装置真空系统运行稳定性探讨

就聚酯连续生产中怎样提高真空系统运行稳定性进行了探讨，对工艺进行技术改造，重点介绍运行中的真空系统清洗情况以及实施后效果     

PET缩聚真空喷啉水系统的改造

剖析了裕华聚酯切片三厂缩聚真空喷呆水系统存在的问题,提出了技术改造方案。实践证明,该技术改造效果明显,同时为其它同类装置的技术改造提供了有益的借鉴。     

论我国硫酸法钛白生产厂的技术改造

从生产装置设计角度，提出了我国中小型硫酸法钛白生产厂技术改造的可行方案。采用真空结晶、常压水解、高位水洗等工艺技术，以及偏钛酸洗涤技术改进，煅烧窑改造和洗水的循环使用等措施，以达到提高TiO2产品档次和收率，以及降低能耗的目的。     

硫酸法生产钛白粉水洗工艺真空系统的设计改造

从硫酸法钛白粉生产中的水洗工艺的推动力——真空系统出发,研究了真空系统对水洗工艺的影响．提出了水洗工艺真空系统改造原则,并对改造思路和方案进行了详细的探讨和分析,通过设计改造,能够达到降能、提产的目的。     

轮胎生产工艺节能技术改造效益分析

对半钢子午线轮胎生产企业实施的炼胶隔离剂热风加温系统节能技术改造、动力循环水系统节能技术改造、硫化工序外排废蒸汽余热回收3个项目的技术原理和节能效益进行分析。3个项目分别采用额定功率小的活塞式压缩机代替功率大的螺杆式空气压缩机、矢量控制型变频器进行负荷调节及由溴化锂制冷机组替代4台电制冷机组等措施,每年可分别节约标准煤505.2,637.2和1 694.8t,节能效果显著;单位产品(每吨轮胎)综合能耗由2010年的428kg标准煤下降到2013年的376kg标准煤,达到了半钢子午线轮胎单位产品能耗先进值。     

三聚氰胺装置废水处理系统技术改造

对废水处理系统的技改原因、技改方案进行了论述,通过技术改造,实现了装置的正常稳定运行和节能减排,并对系统操作优化提出建议。     

Free energy of conformational change in a single chain of polyvinylidene fluoride using molecular simulations

Polyvinylidene fluoride (PVDF) has several crystal forms of which the α-form is nonpolar, while the β-form is polar and has the highest piezoelectric constant. α PVDF, when stretched, transforms into the β form, which has wide applications in sensors and actuators. Steered molecular dynamics simulations are used to study the transformation of a single chain of PVDF from a trans–gauche conformation to an all trans one. The Helmholtz free energy change (∆F) is estimated using Jarzynski's equality. The transformation starts at the chain ends followed by the transformation of the remaining chain. The free energy change for the transformation is found to be always positive, indicating that the TGTG' form has higher thermodynamic stability than the all trans form throughout the studied temperature range. With increasing temperature, free energy change for the transformation increases monotonically.     

煤化工装置的能量转化率研究

根据能量转化率的定义,讨论能量转化率数据的作用与价值,提出选择产品的原则是国家的需求和技术的成熟度.     

330MW供热机组低压缸近零出力热力性能分析

阐述了汽轮机低压缸切缸供热系统工作机理,结合某330MW空冷供热机组,应用Ebsilon软件搭建切缸供热改造前后机组变工况计算模型,基于热力学定律,对比分析改造前后机组能耗分布和供热能力。绘制了纯凝运行、抽汽供热和切缸供热工况能流图,获得机组在不同供热方式下能量流动方向和各部分损失变化。探讨影响机组调峰范围的因素,利用工况图分析低压缸近零出力改造后电热负荷特性及其调峰能力的变化。并结合电力辅助服务市场运营规则进行了调峰补偿收益核算。结果表明：较抽凝运行工况,案例机组完成低压缸近零出力改造后,最大供热能力增加37.1%;额定供热工况电负荷调节能力提高34.8%;发电标准煤耗率降低54.5g/(kW·h), 调峰能力增加的同时热经济性提高。本文从理论上,对低压缸近零出力改造技术的应用提供了定量依据和工程适用范围,为热电联产机组灵活性改造技术应用提供理论支撑。     

“双碳”目标下能源安全定量评价方法

为应对全球气候变化,中国提出了“2030年前实现碳达峰,2060年前实现碳中和”的“双碳”目标。在“双碳”目标下,中国的能源消费结构由传统化石能源为主向可再生能源为主转变,能源结构的转变导致能源安全的内涵发生了改变,能源安全评价方法也将随之发生变化。本文主要总结了各类能源安全的定量评价方法,对比和分析了这些方法的优缺点以及适用范围,详细阐述了基于能源供应安全评价和基于国家或区域能源安全评价方法。在“双碳”目标下,能源安全指标参数与以往化石能源供应安全的评价指标不同,在参数选择上更加关注二氧化碳、二氧化硫、颗粒物的排放等环境指标,以及与之相关的水、粮食等也作为重要的评价指标纳入到能源安全定量评价体系中。在“双碳”目标下,特别是能源结构转型的过渡期,建立合理的能源安全定量评价体系具有重要的现实意义。     

Investigation of structural transformation and residual stress under single femtosecond laser pulse irradiation of 4H–SiC

Silicon carbide (SiC) is an attractive semiconductor material for devices that operate under extreme conditions. However, its high hardness and chemical stability hinder micromachining. Femtosecond laser has been proposed extensively as an effective micromachining tool for SiC. However, the fundamental mechanisms of laser-material interaction during femtosecond laser irradiation process remain elusive. This paper presents a comprehensive study of the structural transformation and residual stress induced by irradiating a 4H–SiC target with a single-pulse femtosecond laser. The energy dependence of the structural characteristics at the spot center and the spatial distribution across the laser spot were determined using optical microscopy and micro-Raman spectroscopy. The effect of the laser fluence on the residual stress was discussed. The obtained results showed that no structural changes occurred at low energy, whereas bond breaking occurred among crystalline SiC (c-SiC) at high energy. A central disk with no structural transformation and no residual stress was formed for the fluence of 22.2 J/cm², owing to phase explosion-induced spluttering. Meanwhile, an inhomogeneous distribution of the structural transformation was generated from the spot centre to the edge. Based on this, threshold fluences for modification and structural transformation were proposed and calculated. The fundamental mechanisms for different laser-fluence regimes are discussed, and some suggestions for improving the surface quality are put forward. This study provides deep insights into the laser-material interaction mechanisms and is beneficial for optimising the utilisation of femtosecond laser for 4H–SiC micromachining.     

Liquid-Phase-Assisted Transformation of Seeded γ-Alumina

α-Al₂O₃-seeded, boehmite-derived γ-Al₂O₃ was transformed in the presence of V₂O₅, resulting in a 205°C decrease in the α-Al₂O₃ transformation temperature and a 74% reduction in the apparent activation energy for the γ- to α-Al₂O₃ transformation at temperatures greater than 850°C. These changes are attributed to the lowered energy barrier for nucleation by seeding and the lowered activation energy for material transport through the liquid relative to the unseeded, solid-state transformation. Growth of the transforming alumina yielded fine-grained α-Al₂O₃ particles which exhibited a highly faceted morphology. It is proposed that the combined control of both nucleation and growth during liquid-phase-assisted transformation provides a potentially powerful technique for tailoring powder characteristics in many material systems which undergo nucleation and growth processes.     

全球能源资源版图变化趋势及启示

全球能源资源版图正在发生深刻调整,美国凭借着页岩油气产量的大幅增加,将成为与中东、俄罗斯并重的油气出口国,全球油气供应也将持续宽松。与此同时,全球能源绿色转型提速,煤炭需求量持续下降,可再生能源将快速发展。这些变化启示我们,在常规情况下,我国能源安全有保障,一方面,应抓住供求宽松契机,优化油气合作布局,同时补齐能源储备短板应对不确定性风险。另一方面,应保持战略定力,继续大力促进新能源产业发展、加快化石能源特别是煤炭及其相关产业转型步伐,积极推进绿色“一带一路”建设,引领区域能源转型。     

Power-to-X im Kontext der Energiewende und des Klimaschutzes in Deutschland

In order to examine the impact of different Power-to-X technologies on the transformation of the German energy system and meeting the climate change mitigation goals, a cross-sectoral energy system model was developed. The results show that Power-to-X will be essential for a successful energy transition. Especially in applications where high energy densities are required and only few other options for defossilization exist, Power-to-X technologies become essential.