地下煤制气制取液化天然气和液氢工艺研究

目的脱除地下煤制气中的酸气,将地下煤制气中的CH₄和H₂分离出来并液化。 方法对常见的分离方法进行对比,确定采用低温精馏法对煤制气进行脱酸气、分离CH₄和H₂并液化。根据低温精馏法的原理,设计了一种全新的地下煤制气脱酸气、分离CH₄和H₂并液化的工艺流程,该工艺主要由两个精馏塔、一个两相分离器和三级氦膨胀制冷系统组成。同时利用HYSYS软件对其进行模拟分析,确定最优参数。 结果该工艺可以将地下煤制气中CO₂的摩尔分数脱除到0,H₂S的摩尔分数脱除到3.65×10-14,满足处理要求。同时可以实现CH₄回收率为99.97%,加压液化天然气(PLNG)的摩尔分数为99.97%,H₂的回收率为98.30%,液氢(LH₂)的摩尔分数为99.99%。 结论该工艺可以有效利用地下煤制气制取PLNG和LH₂,且所需能耗较传统工艺能耗降低了11.64％,具有较高的经济效益。      

超高效液相色谱串联质谱法测定牛奶中三氮脒残留

目的 本研究旨在结合超高效液相色谱－串联质谱(ultra performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS)技术,建立简便、快速的样品前处理方法,对牛奶中的痕量三氮脒残留进行检测。方法 用1%乙酸乙腈溶液振荡提取后,在-4℃条件下高速离心,取上清液旋转蒸干后,用10%乙腈水溶液复溶,用超高效液相色谱-串联质谱仪在正离子扫描及多反应监测(multiple reaction monitoring, MRM)模式下分析,外标法定量。结果 牛奶中三氮脒的检出限(limit of detection, LOD)为5 μg/kg,定量限(limit of quantification, LOQ)为15 μg/kg,在20~1000 μg/L浓度范围内线性良好,相关系数(r)为0.9993。将所研究的方法应用于实际牛奶样本中,其加标回收率在81.65%至85.49%之间,日内精密度分别在4.5%~5.5%,日间精密度在5.9%~8.2%之间。结论 本方法采用振荡提取加低温高速离心净化的前处理方法,简单快速,结合UPLC-MS/MS,可实现痕量水平残留的高灵敏度检测,适用于快速、高灵敏检测牛奶及其他动物源性食品中的三氮脒残留。     

井下防灭火中液态CO2应用分析

以井下防灭火中液态CO2应用为对象开展探究,在分析概述液态CO2防灭火技术的基础上,结合工程实际,对相关技术在煤矿井下生产中的具体应用做出分析探究,并对其应用效果进行总结.结果表明,该技术能够有效控制采空区火灾,对于提升矿井作业安全意义重大.     

硫酸钾尾液冷冻回收高硫钾比矿物工艺研究

以硫酸钾尾液为原料,研究低温冷冻回收高硫钾比矿物合理的工艺技术路线,探寻适宜的贮存条件,为加工车间夏季高温生产硫酸钾提供优质高硫钾比原料.在低温下进行冷冻试验,根据冷冻结晶矿物产率及其干基组分确定适宜的冷冻温度为-15～5℃,冷冻制得的结晶矿物硫钾比均在3.0～5.1,符合夏季生产硫酸钾所需原料硫钾比>2.5的要求.高...     

相对速度对磁流体液体动密封中界面稳定性的影响

推导了旋转轴液体密封中液-液界面由于相对运动引起的切应力,从相对速度角度对液体动密封界面稳定性问题进行了研究,并对结构进行了改进,将磁流体界面的稳定性问题转化为静态扩散处理.     

围挡式洁净区的单向流特性研究

通过实验分析围挡式洁净区的3个特性指标，即：流线平行度、乱流度和下限风速，并指出其应用价值和市场前景。     

Liquid Letters

Using the interfacial jamming of cellulose nanocrystal (CNC) surfactants, a new concept, termed all‐liquid molding, is introduced to produce all‐liquid objects that retain the shape and details of the mold with high fidelity, yet remain all liquid and are responsive to external stimuli. This simple process, where the viscosity of the CNC dispersion can range from that of water to a crosslinked gel, opens tremendous opportunities for encapsulation, delivery systems, and unique microfluidic devices. The process described is generally applicable to any functionalized nanoparticles dispersed in one liquid and polymer ligands having complementary functionality dissolved in a second immiscible liquid. Such sculpted liquids retain all the characteristics of the liquids but retain shape indefinitely, very much like a solid, and provide a new platform for next‐generation soft materials.     

液体炸药的发展及现状

以液体炸药的分类、制备、特性和应用等为切入点,较为详细地论述了液体炸药的现状和发展。指出混合液体炸药因具有原料来源广泛、制造简便、综合性能良好等许多独一无二的特性,而被广泛应用于军事和民用领域,并获得了长足的发展。同时警告液体炸药已成为恐怖分子实施爆炸恐怖活动的主要选择。建议加强液体炸药相关原料的管理。     

Simulating Retention in Gas–Liquid Chromatography: Benzene, Toluene, and Xylene Solutes

Accurate predictions of retention times, retention indices, and partition constants are a long sought-after goal for theoretical studies in chromatography. Although advances in computational chemistry have improved our understanding of molecular interactions, little attention has been focused on chromatography, let alone calculations of retention properties. Configurational-bias Monte Carlo simulations in the isobaric–isothermal Gibbs ensemble were used to investigate the partitioning of benzene, toluene, and the three xylene isomers between a squalane liquid phase and a helium vapor phase. The united-atom representation of the TraPPE (transferable potentials for phase equilibria) force field was used for all solutes and squalane. The Gibbs free energies of transfer and Kovats retention indices of the solutes were calculated directly from the partition constants (which were averaged over several independent simulations). While the calculated Kovats indices of benzene and toluene at T=403 K are significantly higher than their experimental counterparts, much better agreement is found for the xylene isomers at T=365 K.     

多室内环流反应器中液体循环量的试验验证与模拟

目的 对液相氧化脱硫多室内环流反应器液体循环量的影响因素进行模拟和验证。方法 采用CFD数值模拟,基于欧拉-欧拉多相流模型,对液相氧化脱硫多室内环流反应器进行气液两相流模拟,考查了酸气流量和空气流量对液体循环量的影响。结果 利用数值模拟得到的液体循环量与利用靶式流量计测得的液体循环量误差小于10%。当酸气中H₂S体积分数不超过3%时,液体循环量(z)与酸气流量(x)、空气流量(y)之间的关系式为：z=-474.996+0.358x+0.487 3y。结论 欧拉-欧拉两相流模型能够准确地预测液相氧化脱硫反应器内液体循环量。