Applications of high-gravity technologies in gas purifications: A review

The traditional gas purification techniques such as wet gas desulfurization, with their advantages of large-scale implementation and maturity, have still been widely used. However, the main drawback of these techniques is the low transfer efficiency, which normally needs towers as tall as tens of meters to remove the pollutants. Therefore, new technologies which could enhance the mass transfer efficiency and are less energy-intensive are highly desirable. As a process intensification technology, high-gravity technology, which is carried out in a rotating packed bed(RPB), has recently demonstrated great potential for industrial applications due to its high mass transfer efficiency, energy-saving, and smaller volume. This consequently provides higher efficiency in toxic gas removal, and can significantly reduce the investment and operation costs. In this review, the mechanism,characteristics, recent developments, and the industry applications of high-gravity technologies in gas purifications, such as hydrogen sulfide, nitrogen oxide, carbon dioxide, sulfur dioxide, volatile organic compounds and nanoparticle removal are discussed, most of the demonstration projects and practical application examples in gas purification come from China. The perspective and prospective of this technology in gas purification and other fields are also briefly discussed.

Isolation and Purification of Unstable Iridoid Glucosides from Traditional Chinese Medicine by Preparative High Performance Liquid Chromatography Coupled with Solid-phase Extraction

An efficient preparative method was successfully developed for isolation and purification of unstable components from medicinal plant extracts, using a combined method of preparative high performance liquid chro-matography(HPLC) and solid-phase extraction(SPE). The aim of this study was to obtain an effective method with high preparative efficiency and importantly to avoid the transformation of unstable compounds. The preparative HPLC system was based on an LC/MS controlled four-channel autopurification system. The SPE method was performed with a C18 packing material to trap the target compounds and to remove the acidic additive derived from the mobile phase. Using this method, the unstable iridoid glucosides(IGs) as model compounds were successfully isolated and purified from the extract of Hedyotis diffusa Willd. Six IGs(including one new minor IG) and one nucleotide compound were simultaneously obtained, each with a purity of 91% as determined by HPLC. The structures of the isolated compounds were identified by UPLC/Q-TOF MS, UV, 1D and/or 2D NMR. It was demonstrated that the combination of preparative HPLC with SPE is a versatile tool for preparative purification of unstable compounds from complex natural products.

Numerical simulation and experimental verification of axial-directional crystallization purification process for high-purity gallium

A transient numerical model was applied to simulating the axial-directional crystallization purification(ADCP) process of gallium(Ga) raw material at different coolant temperatures(Tc), and the evolutions of melt/crystal(m/c) interface shape, temperature distribution and thermal stresses were simulated and analyzed. The results showed that the m/c interface shape, temperature distribution, and thermal stress in the Ga material were determined by the Tc in the crystallizer during the ADCP process. The temperature gradient and thermal stress in the grown Ga crystal increased with decreasing Tc. At Tc=15 ℃, the m/c interface shape was flat, and the temperature gradient was ideal. Therefore, the Ga materials with lower thermal stresses and suitable m/c interface shape, and an ideal efficiency of impurity removal were obtained. The purity of Ga reached 6 N standard by using ADCP process repeated 6 times at Tc of 15 ℃. The results of the simulation showed good agreement with the experimental results.

KAOLIN CLAY PURIFICATION BY DRY HIGH GRADIENT MAGNETIC SEPARATION

A new method-dry High Gradient Magnetic Separation （HGMS）-to remove iron from ultrafine kaolin powder is described. A new kind of disperser, which breaks down the particle clusters in the powder by high speed gas flow from an air compressor, is used to completely disperse the powders. The dispersed particles are passed through vibrating HGMS by a vacuum pump to remove the iron. The magnetic and nonmagnetic fractions are separately collected by cloth collectors. Dry HGMS laboratory experiments are carried out. A product containing 0.90％ Fe2O3 was obtained, and the recovery was 70％.

High-speed countercurrent chromatography for purification of single-walled carbon nanotubes

A new chromatographic purification of single-walled carbon nanotubes using high-speed countercurrent chromatography is reported. The purification was accomplished on the basis of experiment that dispersed the single-walled carbon nanotubes with sodium dodecyl sulfate, and the result mixture was separated using the two phase system composed of n-butanol/water = 1/1 （v/v）. The sizes of SWNTs separated were observed by scanning electron microscopy. The results demonstrated that the high-speed countercurrent chromatography possessed a good efficency for purification of single-walled carbon nanotubes.

Hydrometallurgical Purification of Some Clay Deposits for High Temperature Applications

The characterization of five different Nigerian clay deposits has been carried out by employing three different characterization techniques (X-ray Diffraction, X-ray Fluorescence and Scanning Electron Microscopy/EDX). The clays obtained from the various deposits were carefully prepared for the analyses and the results obtained were compared to confirm the consistency and reliability of the different methods employed. The results revealed the various desirable (SiO2 and Al2O3) and deleterious (Fe3O4, K2O, MgO, MnO and Na2O) elements and compounds contained in the clay samples in the various proportions and the appropriate purification technique required for preparing the clays for high temperature applications. Consequent upon the identification of the deleterious impurities, oxalic acid at different concentrations was used to leach the impurities out of the various clays. However, three out of the five deposits were chosen for purification because they possess the least quantities of the most deleterious (Fe2O3) of the impurities.

Integrated development and industrial application of high sour natural gas purification technology

Aiming at acute characteristics of flammability,explosibility,causticity and leakiness of high sour natural gas,giving full consideration to local natural conditions in Sichuan Province and starting with purification process,the paper analyzed process configurations,energy utilization and conservation,safety and environment protection measures. The integrated technology and engineering scheme for high sour natural gas purification was established and successfully used in industrial application.

Optimization of High-Performance Liquid Chromatography Parameters for Purification of Oligonucleotide-A

The modification of high-performance liquid chromatography parameters leads to a more effective oligonucleotide-A purification process. Using various experimental parameters such as buffer, concentration, and pH, a method for optimizing the purification of an oligonucleotide-A on a reverse-phase C18 column was created. To purify oligonucleotide-A, High-Performance Liquid Chromatography (HPLC), Ultraviolet-Visible Spectrophotometry (UV-Vis), Liquid Chromatography-Mass Spectrometry (LC-MS), and lyophilization were used. Chromatographic data were collected with a semi-prep HPLC system, quantified with the UV-Vis technique, and validated with the LC-MS method. The most optimized parameters found to obtain the purity of 93.0% are 40 mM triethylammonium bicarbonate (TEAB) buffer with pH 7, which is approximately 6.0% higher than the reported method of which the purity is 87.0%. However, the yield under these conditions was reduced by about 5%. The worst possible optimized settings that resulted in the lowest purity (84.0%) and yield (69.0%) are 10 mM ammonium acetate (NH4CH3CO2) with pH 7.

The Purification and Rejuvenation and Breeding Technology of Rice Variety Yunjing 29 with Fragrant and Soft Rice

Yunjing 29 bred by Institute of Food Crops of Yunnan Academy of Agricultural Sciences is a new conventional japonica rice variety with fragrant and sof rice, it was examined and approved by Yunnan Provincial Variety Examination and Approval Committee in March of 2011. The variety is early-maturing, high-yield and good-quality, and has resistances to lodging, blast and bacterial leaf blight, its rice is sweet soft, goluptious and lucidus as well as not coarse when it is cold, so it is a good commodity. To further promote the popularization and cultivation of the variety, maintain its characteristics of high quality and high yield, and prevent commingling and degeneration, the purification and rejuvenation as well as breeding technology of high-quality seeds were proposed after continuous exploration and study.

CO2 residual concentration of potassium-promoted hydrotalcite for deep CO/CO2 purification in H2-rich gas

Elevated-temperature pressure swing adsorption is a promising technique for producing high purity hydrogen and controlling greenhouse gas emissions. Thermodynamic analysis indicated that the CO in H-rich gas could be controlled to trace levels of below 10 ppm by in situ reduction of the COconcentration to less than 100 ppm via the aforementioned process. The COadsorption capacity of potassiumpromoted hydrotalcite at elevated temperatures under different adsorption（mole fraction, working pressure） and desorption（flow rate, desorption time, steam effects） conditions was systematically investigated using a fixed bed reactor. It was found that the COresidual concentration before the breakthrough of COmainly depended on the total amount of purge gas and the COmole fraction in the inlet syngas.The residual COconcentration and uptake achieved for the inlet gas comprising CO（9.7 mL/min） and He（277.6 mL/min） at a working pressure of 3 MPa after 1 h of Ar purging at 300 mL/min were 12.3 ppm and0.341 mmol/g, respectively. Steam purge could greatly improve the cyclic adsorption working capacity, but had no obvious benefit for the recovery of the residual COconcentration compared to purging with an inert gas. The residual COconcentration obtained with the adsorbent could be reduced to 3.2 ppm after 12 h of temperature swing at 450 °C. A new concept based on an adsorption/desorption process, comprising adsorption, steam rinse, depressurization, steam purge, pressurization, and high-temperature steam purge, was proposed for reducing the steam consumption during CO/COpurification.

Using expansion units to improve CO_(2) absorption for natural gas purification——A study on the hydrodynamics and mass transfer

The usage of capillary tubes for CO_(2) absorption suffers from small re sidence time,which leads to reduced performance for large throughput.This work presents a method of connecting expansion units to capillary tubes to serve as a residence time delayer.The effect of the expansion unit on gas-liquid hydrodynamics,pressure drop and mass transfer coefficient(k_(L)a) are investigated under various operating pressures up to 4.0 MPa,for both physical and chemical absorption.A novel periodic jetting flow is found in the expansion unit,which can intensify the CO_(2) absorption.Experimental results show that the strategy can significantly decrease the pressure drop while maintaining the absorption performance to a large extent.The overall k_(L)a for physical and chemical absorption are correlated to pressure drop,respectively.Besides,CO_(2) loading in rich absorbents increases dramatically compared to literature studies with only micromixers or capillary tubes,which is bene ficial to regenerate solvent.The study verifies the concept that pre-treatment with water can largely reduce the usage of amine s,and can also provide a guide for process design in natural gas purification such as biogas recovery.

SYNTHESIS AND PURIFICATION OF MODIFIED ANTISENSE OLIGODEOXYRIBONUCLEOTIDES

The synthesis and purification of modified antisense of igodeoxyriboucleotides (MAO ) are des cribed. A new oligonucleotide purification method and a novel activating agent, dimethyl sulfoxide, for thecondensation reaction are used. EDTA has been attached covalently to the 5’ end of the oligodeoxyribonucleotides sequence via an ethylenediamine linker in basic triethylammonium solution, then chelated withthe metal ions such as Fe(Ⅱ), Co(Ⅱ) or Cu(Ⅱ). High performance liquid chromatorgaphy is used to separate and purify this kind of MAO, using double mobile phase, triethylammonium acetate and acetonitrile. Byusing this routine chemical synthesis method, EDTA can be linked to the 5’ terminus of oligodeoxyribonucleotedes of any desired length and sequence, forming chimeric MAOs.

高含硫天然气净化装置腐蚀特征与典型腐蚀案例分析

相关高含硫天然气净化装置的工程建设、设备制造、材料选型等标准规范较少,多采用或借鉴石油炼制行业标准。普光气田天然气净化厂自2009年投产至今,因高酸性气体腐蚀,以及酸性气体、制造缺欠、材料缺陷等多因素耦合腐蚀,引发装置设备或设施多次泄漏,成为制约工厂安全、高效、长周期运行的主要问题。通过统计分析历年异常事件、设备检维修台账、压力容器管道检测台账等,归纳了高含硫净化装置重点腐蚀区域、影响因素、腐蚀机理,得出湿硫化氢腐蚀、高温硫腐蚀、二氧化硫腐蚀、垢下腐蚀为主要腐蚀形式;从区域、类别、诱因等不同角度归纳了腐蚀分布规律,脱硫、硫磺回收系统腐蚀占比达80%以上;重点剖析了基于硫化氢、液硫、制造缺欠等因素的典型腐蚀案例,提出了高含硫天然气净化装置腐蚀防控措施,为同类酸性气田装置、设备腐蚀监检测和防控提供了借鉴。

高纯铜制备方法及研究进展

高纯铜因其优良的物理化学性质,在集成电路、半导体、航空航天等领域发挥重要作用。我国是铜生产与消费第一大国,但99.999%及以上高纯铜高效制备技术的缺乏制约着铜产业竞争力的提升,如何高效制备高纯铜是行业研究的重点。本文从高纯铜的制备方法及生产工艺出发,综述了电解、萃取、离子交换、真空蒸馏、区域熔炼等高纯铜制备工艺的研究现状,主要包括纯化机理、制备效率及提纯效果,着重归纳了添加剂、温度梯度、电流密度、保温时间等因素对制备高纯铜的影响。最后,通过对比湿法工艺与火法工艺的优缺点,重点探讨了火法真空蒸馏制备高纯铜的现状,并根据目前高纯铜制备的研究进展,展望了未来高纯铜制备的发展方向。

五硫化二磷应用开发研究进展

研究了五硫化二磷的应用开发趋势和特点。详细论述了五硫化二磷下游产品的应用、开发及市场前景。加强以高纯五硫化二磷为原料的下游产品的应用开发,以扩大对五硫化二磷的需求,并提高其附加值,促进五硫化二磷行业发展。

五硫化二磷制备润滑油添加剂研究

润滑油添加剂是一种非常重要的五硫化二磷下游产品,对五硫化二磷行业发展具有重要作用。为了促进五硫化二磷行业发展,开展了五硫化二磷制备润滑油添加剂的研究。研究表明:在五硫化二磷下游产品中,润滑油添加剂是对五硫化二磷需求量较大的高端产品,占五硫化二磷总需求量的比重较大,且对五硫化二磷的产品质量要求较高。以五硫化二磷为原料制备的润滑油添加剂主要具有摩擦改善、黏度指数改进、抗磨、分散和抗氧化等功能,按功能可分为单功能润滑油添加剂和多种功能润滑油添加剂。单功能润滑油添加剂可显著改进润滑油在一定方面功能,但若需改进润滑油多方面功能时,需添加多种具有单功能的添加剂,添加剂使用量大,使用不便,成本较高;多功能润滑油添加剂可以单一添加剂实现对润滑油在多方面功能的改进,添加剂使用量小,使用简便,成本较低。多功能添加剂是润滑油添加剂未来发展的趋势和热点,应着重利用五硫化二磷制备多功能润滑油添加剂的应用开发。

“DNA粗提取和鉴定”实验设计与改进

对DNA粗提取与鉴定实验进行优化,探究植物组织的多种破碎方法对DNA粗提取的影响,并用氯仿等有机物对DNA粗提取物进一步纯化,分析DNA未纯化与纯化后的纯度差异。结果显示,相较于破壁机破碎、加液氮研钵研磨以及玻璃匀浆器研磨,不添加液氮用研钵研磨效果更好。DNA粗提液经纯化后纯度显著提高,蛋白质及盐类等污染明显减少。

高含硫天然气净化装置胺液系统阻泡技术研究与应用

为防止天然气净化装置胺液发泡,进而引起拦液、冲塔、产品质量不合格等事故的发生,对发泡机理、发泡物的组分以及发泡物性质等进行分析,总结发泡物对胺液的影响,开展胺液系统阻泡技术研究并进行了工业化应用。新技术应用后,消泡效率提高了约35%、发泡频率降低约71%,保障了企业安全平稳生产,经济效益显著,为同类化工企业提供了技术借鉴。

高含硫天然气净化装置过滤器液位计引管失效分析

介绍了某大型净化厂脱硫单元原料气过滤器失效的问题,对过滤器液位计引管直管段及焊接法兰进行化学成分、金相组织、断口形貌等分析,探讨失效的主要原因。结果表明,原料气过滤器失效的原因是过滤器的材质不符合要求,长期处于偏低温度和酸性介质环境中导致原料气过滤器氯化物应力腐蚀失效。准确掌握设备失效成因,有针对性地采取防护措施,对于确保装置长周期安全运行具有重要的意义。

江西某脉石英制备4N5级高纯石英砂试验研究

利用江西某脉石英岩心矿石制备高纯石英砂,探究了磨矿时间、磁选、擦洗、矿浆pH值对高纯石英砂纯度的影响,确定最佳试验条件,采用4段磁选-2段擦洗-2段水洗-2段浮选-2段脱药-焙烧-水淬-酸浸工艺,得到的最终产品石英砂SiO_(2)含量(质量分数,下同)达到4N5级,总杂质含量为54.84μg/g,其中Al元素含量为16.76μg/g,Na元素含量为5.83μg/g,K元素含量为6.46μg/g,Fe元素含量为17.50μg/g。该工艺对对脉石英矿物制备高纯石英砂具有一定指导意义。