Specializing liquid electrolytes and carbon-based materials in EDLCs for low-temperature applications

Electric double-layer capacitors(EDLCs) are emerging technologies to meet the ever-increasing demand for sustainable energy storage devices and systems in the 21 st Century owing to their advantages such as long lifetime, fast charging speed and environmentally-friendly nature, which play a critical part in satisfying the demand of electronic devices and systems. Although it is generally accepted that EDLCs are suitable for working at low temperatures down to-40℃, there is a lack of comprehensive review to summarize the quantified performance of EDLCs when they are subjected to low-temperature environments. The rapid and growing demand for high-performance EDLCs for auxiliary power systems in the aeronautic and aerospace industries has triggered the urge to extend their operating temperature range,especially at temperatures below-40℃. This article presents an overview of EDLC’s performance and their challenges at extremely low temperatures including the capability of storing a considerable amount of electrical energy and maintaining long-term stability. The selection of electrolytes and electrode materials is crucial to the performance of EDLCs operating at a desired low-temperature range. Strategies to improve EDLC’s performance at extremely low temperatures are discussed, followed by the future perspectives to motivate more future studies to be conducted in this area.

Removal of Nitrogen Compounds from Shale Diesel Fraction Using Ionic Liquid [C_4mim]HSO_4

Ionic liquid(IL) 1-butyl-3-methylimidazolium hydrosulphate([C_4mim]HSO_4) was synthesized and its denitrogenation performance was investigated for diesel fraction with high content of nitride from oil shale. The effects of the temperature, the mass ratio of oil to IL, the mass ratio of water to IL, the extraction time, the settling time and the regeneration of IL on the N-removal efficiency were studied. Experimental results showed that the ionic liquid [C_4mim]HSO_4 exhibited excellent denitrogenation performance, and about a 90% basic N-extraction efficiency and a 71% total N-extraction efficiency were achieved under the conditions covering a temperature of 30 ℃, an oil/IL mass ratio of 7:1, a H_2O/ IL mass ratio of 2:1, an extraction time of 20 min and a settling time of 120 min. In addition, the basic N-removal efficiency can still reach 74% during five recycles of the ionic liquid.

Desulfurization of Diesel Fuel by Extraction with [BF4]^--based Ionic Liquids

The extractive removal of sulfur compounds （S-compounds） from Dongying and Liaohe diesel fuels with [BF4]^--based ionic liquids were systematically investigated. The results show that the absorption capacity of an ionic liquid for the S-compounds in diesel fuels relies on its structure and its size. In the case of the two examined diesel fuels, both elongating the cation tail length and increasing the mass ratio of ionic liquid/diesel fuel promote the desulfurization ability of the examined ionic liquids. The results also show that imidazolium-based ionic liquids display higher extraction efficiencies than pyridinium-based ionic liquids, presumably owing to the fact that the rings of the S-compounds are similar to the imidazolium head ring. With the 1 ： 1 mass ratio of ionic liquid/diesel fuel, the rates of the first desulfurization of Dongying and Liaohe diesel fuels using [C8mim][BF4] amount to 29.96% and 39.76%, suggesting that [C8mim][BF4] is a promising extractant for desulfurization of these diesel fuels.

Removal of Nitride from Shale Diesel Fraction with FeCl3-Based Ionic Liquids

FeCl3-based ionic liquid [Bmim]Br/FeCl3 with lower viscosity was synthesized and its structure was character-ized with FT-IR spectroscopy. The denitrogenation performance of the ionic liquid was investigated using the Fushun shale diesel fraction with high nitrogen content. Experimental results showed that the ionic liquid presented good denitrogenation performance and the basic N and total N removal efficiency can reach 95.29% and 89.77% under conditions covering a tem-perature of 30 ℃, an IL/oil mass ratio of 1:1, an extraction time of 30 min, and a settling time of 2 h. Correspondingly, the basic N and total N contents in shale diesel fraction dropped from the original 5454 μg/g and 9832 μg/g to 257 μg/g and 1006 μg/g, respectively. In addition, the basic-N removal efficiency can still reach 60% at an IL/oil mass ratio of 1:7 during four recycles of the ionic liquid.

Removal of Basic Nitrogen Compounds from Diesel Fraction with NMP-0.5ZnCl_(2) Coordinated Ionic Liquid

An inexpensive coordinated ionic liquid NMP-0.5ZnCl_(2) was synthesized by reacting N-methyl-pyrrolidone with anhydrous ZnCl_(2),and its structure was characterized with FT-IR spectroscopy.The performance of IL for removing basic nitrogen compounds from model oil containing quinoline and actual coker diesel was studied.Experimental results showed that the IL,NMP-0.5ZnCl_(2),exhibited a good denitrogenation performance,which can be attributed to its low viscosity and unoccupied orbitals of Zn ion,while obtaining a 99.68%quinoline removal efficiency under conditions covering a temperature of 50℃,an IL/model oil mass ratio of 1:2,and a reaction time of 30 min.In the case of coker diesel,above a 91%basic N-removal efficiency(with N-content reduced from 536μg/g to 47μg/g)was realized by the IL after 5-stage extraction.Moreover,the quinoline extraction efficiency could still reach 96.73%during four recycles of the IL.

Removal of Basic Nitrogen Compounds from Coker Diesel by Eutectic Ionic Liquid

The eutectic ionic liquid （EIL） tetraethyl ammonium bromide-malonic acid （TEAB-Mal） was synthesized, with its structure characterized by the FT-IR spectroscopy and the 1H NMR spectrometry. The performance for removal of basic nitrogen compounds by EIL was studied using coker diesel as the feedstock. Experimental results showed that the EIL （TEAB-Mal） exhibited a good denitrogenation performance, leading to a 93.6% of basic N-removal efficiency under reaction conditions covering： a temperature of 30 ℃, an EIL to oil mass ratio of 1：1, an extraction time of 30 min, and a settling time of 120 min, while the basic nitrogen content in diesel dropped from 580 μg/g to 37 gg/g. In addition, the efficiency for extraction of basic N-compounds could still reach 62.9% at am EIL/oil mass ratio of 1：7 after four recycles of the EIL.

Controllable synthesis of polyoxymethylene dimethyl ethers by ionic liquids encapsulated in mesoporous SBA-16

The promising combustion and emission properties of polyoxymethylene dimethyl ethers(PODEn)are of significant interest.However,the synthesis of PODEn products with desired chain lengths is still a problem facing synthetic PODEn.Herein,a series of unique IL@SBA16Cx solid catalysts are prepared by encapsulation of ionic liquids(ILs)within the nanocage of SBA16 through a silylation method.The structure of the encapsulated catalyst was characterized by UVvis spectra,Fourier transform infrared(FTIR),N2 adsorptiondesorption isotherms,Powder Xray diffraction(XRD),Transmission electron microscopy(TEM)and Elemental analysis.The encapsulated catalysts show similar catalytic activity to the homogeneous counterparts and display higher selectivity to the targeted PODE35 products than their homogeneous counterparts in the synthesis of PODEn from methanol(MeOH)and trioxymethylene(TOM).The encapsulated catalysts exhibit a superior PODE35 selectivity and could be the promising catalysts for PODEn synthetic reaction.

Experimental Investigation on Diesel Engine Performance Using Nano Air-Bubbles Mixed into Gas Oil

The authors studied diesel combustion improvement with a reformed fuel that mixed nano air-bubbles by using an EMNB （ejector-type micro-nano bubbler）. The EMNB performs adequately and is smaller （20 mm diameter, 34 mm length） than other micro-nano bubblers. It is quite possible to install it in an actual engine. An experiment was performed using a single cylinder engine with a dish or square shaped combustion chamber cavity, and in order to compare the engine speed change, we also used a four cylinder engine with a turbo-charger. The results showed that an improvement in specific fuel consumption, a decrease in the density of the exhaust smoke and an improvement in charging efficiency etc. were achieved by mixing nano bubbles into gas oil under most conditions. It is confirmed that combustion was promoted and improved by a physical and chemical action through mixing the nano bubbles into gas oil.

Non-haloaluminate ionic liquids for low-temperature electrodeposition of rare-earth metals—A review

The inherent advantages of ionic liquids （ILs） in electrochemistry have received extensive attention in recent two decades. As a new generation of ILs, non-haloaluminate ILs exhibit better benefits and fewer drawbacks compared to haloaluminate based ILs, which are more qualified for metal electrodeposition, especially reactive metals. In this brief review, the recent developments regard- ing the application of non-haloaluminate ILs as solvents for low-temperature electrodeposition of rare-earth （RE） metals are outlined. In addition, the current problems and an outlook on future research are presented.

液相色谱在柴油多环芳烃分析中的应用

本文旨在应用高效液相色谱(HPLC)技术对柴油中的多环芳烃(PAHs)进行定性和定量分析。PAHs是一类具有高毒性和致癌性的有机化合物,对环境和人体健康构成严重威胁。实验中,通过液液萃取法提取柴油样品中的PAHs,使用氰基键合硅胶固定相进行色谱分析。结果表明,所采用的HPLC方法能够有效分离和检测柴油中的多种PAHs,具有较高的分辨率和灵敏度。主要检测的PAHs包括双环芳烃(DAHs)和三环芳烃(T+AHs)。实验结果显示,不同PAHs在柴油中的浓度分布反映了其燃烧特性和污染来源。该方法的有效性和可靠性在实验中得到了验证,但样品前处理和色谱条件的优化仍有改进空间。本文的研究为柴油中PAHs的分析提供了一个有效的技术手段,对环境监测和污染控制具有重要意义。

上行式双区复合液相柴油加氢技术的开发及应用

通过分析发现影响液相柴油加氢技术超深度脱硫效果的主要原因是油品中溶解有反应副产物硫化氢。以真实油品模拟计算了硫化氢在柴油中的溶解规律和分布情况,发现补入少量的氢气就可以实现液相工艺进行超深度加氢脱硫,由此开发了上行式双区复合液相柴油加氢技术(SLHT Dr)。中型试验结果表明,在设置的第二反应区中按照氢油体积比为30~50补入氢气,就能够克服加氢过程中硫化氢对深度脱硫反应的抑制作用,可在缓和的工艺条件下(反应温度305℃、体积空速6.0 h^(-1))获得硫质量分数小于10μg/g的精制柴油。SLHT Dr工业应用结果表明,装置能耗比同类技术降低11.9%,实现了低能耗生产,减少了生产环节的碳排放,可为未来柴油质量进一步升级及减少碳排放提供技术支撑。

柴油加氢催化剂级配技术研究及其在SLHT工艺中的应用

以高终馏点、高硫含量、高芳烃含量的混合柴油为原料,在固定床连续加氢反应器上研究了NiMo型催化剂和CoMo型催化剂的反应性能特点,并在此基础上研究了催化剂的三种级配方案。实验结果表明,当NiMo型催化剂和CoMo型催化剂的体积比为1∶1时,加工劣质原料时该级配催化剂具有较强的脱硫活性,还能降低氢耗。与优化级配接近的催化剂体系应用在2.2 Mt/a中国石化连续液相柴油加氢精制工艺装置上,在平均氢油体积比(简称氢油比)为144.2,平均液时空速高达1.37 h-1时,原料二次油质量分数平均为15%、总芳烃质量分数为26%~36%、溴价(100 g原料油)平均值为15.3 g、95%馏出温度基本在360~385℃,第一周期运行1245 d,产品硫含量稳定低于10μg/g,装置平均氢耗率仅为0.74%。

低排温条件下混合器本体温度对尿素雾化效果的影响

为了改善柴油机低排温(200℃)下尿素雾化效果不好的问题,本文研究了柴油机低排温条件下混合器本体温度对SCR系统的影响。基于云内4102柴油机,在1200 r·min^(-1)、20%负荷条件下,运用计算流体动力学(CFD)技术进行数值模拟。通过对比2种混合器的压降、迹线、混合器上壁面液膜分布情况,选取更适合的混合器类型。通过改变混合器的本体温度,来对比分析不同温度的混合器对壁面液膜和催化器前端NH 3均匀性系数的影响。研究结果表明:混合器本体温度的变化对于液膜的形成影响较大,混合器本体温度从100℃升高到200℃时,混合器上液膜区域明显减少。混合器本体温度的升高对NH 3均匀性系数有显著影响。随着混合器本体温度升高,NH 3均匀性系数明显升高,且随着温度的不断升高,NH 3均匀性系数越来越接近1。使混合器保持合适的温度,能够有效提高尿素的雾化效果和NH 3均匀性系数。

Hydrogen-bonded organic framework-ionic liquid composite quasisolid electrolyte for high-performance lithium battery

Ionic liquids(ILs)hold great promise as highperformance electrolyte material due to their unique advantages including nonvolatility,high thermal stability and high ionic conductivity.However,the IL-based electrolytes always suffer from serious ion aggregation and high viscosity at low temperatures,leading to significantly decline in ionic conductivity.Here,hydrogen-bonded organic framework-ionic liquid composite quasi-solid electrolyte(high temperature treatment(HT)-HOF-IL CQSE)was prepared through confining the IL electrolytes(ILEs)into the pore of HOF lamellar framework.The weak hydrogen bonding interactions within HOF nanosheets,together with the generated interactions between ILE and HOF,enable uniform and continuous distribution of ILE in HOF lamellar framework.This effectively inhibits the ion migration of ILE,which meanwhile serves as Li+transfer sites,affording high ionic conductivity of 5.7×10^(-5)S·cm-1 at-60 ℃,with high lithium-ion transference number of 0.69,whereas ILEs usually lose ionic conduction ability at such low temperatures.The assembled Li symmetrical cell can stably cycle at 0.2 mA·cm^(-2)and^(-2)0 ℃ for more than 1500 h.The LiFePO_(4)|HT-HOF-IL CQSE|Li cell shows excellent cycling performance at 0.5 C at a wide temperature range of^(-2)0 to 60 ℃.This work may pave a new avenue for the development of high-performance IL-based composite electrolytes.

示差折光检测器高效液相色谱法测定中间馏分芳烃含量的不确定度分析

采用示差折光检测器高效液相色谱法测定中间馏分芳烃含量,使用不确定度评估方法来建立数学模型,对不确定性来源进行分析,计算各个不确定度分量的结果,然后评估合成标准不确定度和扩展不确定度。评定结果表明,标准溶液配制过程产生的不确定度分量最大,其中以质量称量过程中的不确定度最大,其次是定容和标准物质纯度引入的不确定度;标准曲线拟合引入的不确定度次之。此外,值得关注的还有数值修约和测量重复性引入的不确定度。取置信区间为95%,包含因子k=2,总多环芳烃质量分数测定结果为10.4%±1.1%,总芳烃质量分数测定结果为23.9%±2.7%。

喷油特性对F-T煤制油压力振荡影响规律研究

为了减小燃烧噪声,确定影响柴油机高频压力振荡的关键因素,在某型电控高压共轨柴油发动机上燃用的清洁代用燃料Fischer-Tropsch(F-T)煤制油,选取柴油机典型运行工况,研究不同喷油特性条件下柴油机燃烧压力振荡的时域和频域特性。结果表明:推后主喷提前角和提前预喷提前角会使放热率降低,压力振荡幅值减小,气缸压力级也有明显减小的趋势;减小预喷油量会使压力升高率和放热率降低,气缸声压级减小,压力振荡现象减缓,使燃烧更加柔和;提高喷射压力,会使喷油速率增大,燃油雾化效果增强,混合气放热率提升,放热率曲线也随之上升,气缸声压级增大,发动机缸内燃烧压力振荡幅值增大。喷射压力是影响压力振荡的最显著的参数,喷射压力从85MPa上升至115MPa时,压力振荡幅值增加一倍以上;预喷油量对F-T煤制油发动机的燃烧压力振荡影响不显著;同时压力振荡的产生与放热率的变化呈现出较强的相关性。

液相柴油加氢反应器内件损坏原因分析与对策研究

SLHT液相柴油加氢装置取消了复杂的高压循环氢系统,代之以简单的循环油系统,采用上流式反应器,反应器内全液相操作,反应器的长径比、床层高度不受双相流动模型的限制,内构件少,能耗降低显著,比传统的滴流床技术低40%以上。不同于传统的滴流床加氢反应器,上流式反应器在压降升高后无法进行催化剂撇头,使得反应器压降成为制约装置长周期安全平稳运行的主要瓶颈。本文对因反应器压降高造成内件损坏的原因进行分析总结,提出改进压板层约翰逊网安装方式、完善操作工况、降低反应循环比、优化催化剂装填方案等措施,取得显著效果,对同类液相柴油加氢装置具有较好的借鉴和推广价值。

离子液体萃取脱硫的探索性研究

用不同性质的离子液体(IL)萃取脱除模拟油品(二苯并噻吩和萘的正己烷溶液)中的含硫有机化合物,考察了离子液体的离子类型、用量对脱硫效果的影响。结果表明,离子液体萃取脱硫可以在10 min内达到萃取平衡;随着离子液体与油相体积比的增大,脱硫效果明显改善;离子液体中的阳离子和阴离子对脱硫效果影响很大,疏水性离子液体1-丁基-3-甲基咪唑六氟磷酸盐([BMIM]PF6)对硫化物的萃取量远远大于亲水性离子液体1-丁基-3-甲基咪唑四氟硼酸盐([BMIM]BF4)的萃取量;当V(IL)/V(Oil)=1时,[BMIM]PF6和[BMIM]BF4萃取实际柴油中的硫化物,硫质量分数从5.43%分别下降至2.91%和4.10%。

功能化酸性离子液体催化柴油氧化脱硫的研究

以功能化酸性离子液体为催化剂,30%双氧水为氧化剂,将加氢柴油中的含硫化合物氧化为相应的砜类物质,并用N-甲基吡咯烷酮(NMP)萃取一次。同时考察了反应温度、反应时间和催化剂用量等因素对氧化脱硫反应的影响,得出最佳反应条件为,3 mL油样(硫的质量分数为200×10-6)、1.5 g酸性离子液体、0.3 mL H2O2、25℃,3.5 h、VNMP/Vdiesel=1∶1,脱硫率可达到86.7%,柴油硫的质量分数仅为25×10-6左右,反应结束后,可通过简单的倾倒将油样和催化剂分离,重复使用5次,其催化活性变化不大。

乙醇-柴油混合燃料对柴油机性能及排放的影响

通过对乙醇含量分别为500、1000、1500和2000的混合燃料及纯柴油5种油品的对比实验,研究了燃用乙醇 柴油混合燃料时,柴油机燃油经济性、功率及排放特性的变化规律.实验结果表明,燃用乙醇 柴油混合燃料,柴油机的能量消耗率在乙醇含量为1500时最佳,功率有所下降,但由于乙醇添加量较小,总体来说对发动机性能影响不大.在排放特性方面,NOx的比排放量基本随着乙醇掺烧比例的增加而减少;HC、CO的比排放量基本上随着乙醇掺烧比例的增加而增加;随着乙醇掺入比例的增加,发动机的可见烟度和滤纸式烟度均有显著的降低,干碳烟(DS)的比排放量也呈下降趋势.