Selectivity enhancement in catalytic purification reactions by poisons

This work investigates the moderating influence of poisons on the selectivity for consecutive catalytic purification reactions such as removal of acetylene from ethylene streams. It is shown that poisons, which compete for unadsorbed sites, may cause a significant enhancement of the selectivity by reducing the deleterious impact of diffusional limitations. A numerical example is used to examine the influence of the catalytic activity and concentration of the impurity on the desirable level of the poison in the reaction mixture.     

液化天然气工厂天然气净化工艺的选择

介绍了天然气中水分、硫化氢、二氧化碳、重烃、汞及氮气等杂质对LNG工厂液化的影响,以及天然气的净化工艺.根据某公司液化天然气工厂天然气来源变化,说明天然气的组成对天然气净化工艺选择的影响.     

Selectivity in the Oxidation of Aliphatic Ketones by thallic sulphate in aqueous medium

The effects of temperature, structure and sulphuric acid concentration on the selectivity of the oxidation of aliphatic ketones (R¹COR²) ( 1a – g ) by thallic sulphate have been investigated. With increasing temperature the quantity of internal α-hydroxyketone ( 3a – d ) decreases and the quantity of 1-hydroxyketone ( 2a – d ) increases in the oxidation of methyl alkyl ketones (R²>CH₃) ( 1a – d ). The same concerns to the oxidation products of hexan-3-one ( 1e ): 2-hydroxy-hexan-3-one ( 2e ) and 4-hydroxy-hexan-3-one ( 3e ), respectively. “The inverse selectivity temperature” (IST) for oxidation of linear methyl alkyl ketones ( 1a – c ) and hexan-3-one ( 1e ) has been found. With the use of the linear free-energy relationship it has been found that the selectivity of the reaction decreases with increasing the polar and steric effects of substituents R¹, R². With increasing the sulphuric acid concentration the selectivity of the oxidation of methyl alkyl ketones ( 1a , 1d ) increases.     

Anodic film on lead-arsenic alloy in sulphuric acid medium

The phase composition, anodic behaviour and semiconducting properties of the anodic film on Pb-6 at % As alloy have been investigated. The linear relationship between i and t ^–1/2 shows that the anodic film growth is controlled by a diffusion mechanism. The experimental results show that the anodic film contains t-PbO, PbO · PbSO₄, 3PbO · PbSO₄ and some arsenic compounds. The dielectric constant of the film is 2.8 × 10² obtained from the capacitance-time relationship measured at 2500 Hz. The Mott-Schottky plot shows that the film is an n-type semiconductor. The flat-band potential is –0.56 V vs Hg/Hg₂SO₄, and the donor density is 7.2 × 10¹⁵ cm^–3 for the film obtained at 0.9 V vs Hg/Hg₂SO₄ for 2 h on a Pb-6 at % As electrode.     

膜吸收在烟气净化中的应用

膜吸收法是膜分离技术与气体吸收技术相结合的一种新型烟气净化技术,具有传统吸收法和膜分离技术的共同优点。介绍膜吸收法净化烟气的基本原理、常用的膜材料,阐述烟气脱硫/脱硝、脱碳的研究进展。通过膜吸收技术与传统烟气吸收技术对比,表明膜吸收技术在经济性能和环保方面具有优势,应用前景广阔。     

Mykrolis buys Aeronex to expand in gas purification

Semiconductor component supplier Mykrolis Corp has acquired the assets of privately held Aeronex, a maker of gas purification products. The terms of the transaction were not disclosed.     

气膜熄焦在焦化生产中的应用

针对新疆炼焦煤焦炭热态性能较差的现状,开展了气膜熄焦试验,在降低5％主焦煤用量的情况下．仍能保证焦炭的冷热强度。使用气膜熄焦后还可降低焦炭含水量．减少蒸汽排放及改善环境。     

气体膜分离的原理及其应用于酸性气体净化的研究进展

介绍了膜分离气体的原理以及对膜的选择原则,讨论和展望了该技术在酸性气体净化方面的应用前景,并根据膜分离法的特点,介绍了膜分离法与胺法技术集成,进行含酸性气体的深度净化的方法。     

以低温甲醇与聚醇醚为溶剂的工业气净化工艺对比

介绍了低温甲醇洗流程和聚醇醚流程的应用现状,评述了低温甲醇洗流程和聚醇醚流程的工艺特点,分析比较了2种工艺的主要技术指标,着重比较了2种工艺的关键运行参数如溶液消耗、冷量消耗、消耗指标、设备以及投资费用等,并对2种工艺流程的适应性进行了分析。分析和比较后认为:酸性气体吸收流程的选择需综合考虑能耗、装置规模、投资、可操作性、装置稳定性等因素;低温甲醇洗适用于净化度要求高、高压、大规模的工业化装置;聚醇醚工艺适用于净化度要求较低的装置,如IGCC多联产装置,可降低能耗,节省投资。     

Options available in the Solinox vent gas purification process

Vent gases from different operations may contain a wide variety of compounds. Environmental considerations require they be removed down to different levels. To optimize this task a variety of processes has to be applied, or, alternatively, Solinox.     

Multilevel screening of computation-ready,experimental metal-organic frameworks for natural gas purification

In this study, traditional Monte Carlo simulation and density functional theory-based structural optimization methods were combined to screen computation-ready experimental metal-organic framework (MOF) database for the application of natural gas purification. Our results show that about half of the good performing computation-ready experimental MOF structures displayed various degrees of deformation (even collapse) after the structure optimization. This phenomenon attributed to the strong attraction of unsaturated metals which attract nearby organic components. For some materials with deformation, unsaturated metals form new bonds with the adjacent organic linkers creating distortions that would be unrealistic in the experimental materials. For the remaining relatively stable materials whose structural characteristics did not change too much, we further studied the adsorption performance of their optimized structures. Finally, 12 good-performing MOF materials with high stability were found which could greatly improve the possibility for constructing robust MOFs that could hold open metal sites by experiments.     

Numerical modeling of gas hydrate decomposition in gas injection into a porous medium

The decomposition of gas hydrates during the injection of gas into a porous medium is studied in planar one-dimensional and axisymmetric self-similar formulations. The effect of the parameters of the porous medium and the pressure and temperature of an injected gas on the length of the region of gas hydrate decomposition in a porous stratum is analyzed.     

Thin film graphene oxide membrane: Challenges and gas separation potential

Graphene oxide membranes were prepared by vacuum and pressurized ultrafiltration methods on the 12% modified Polyacrylonitrile (12mPAN) substrate to specify challenges, salient features, future directions, and potential of GO membrane for separation fields using characterization techniques and gas separation test (studied gases are CO₂, He and N2), which is an efficient tool for better understanding of GO membrane behavior. GO membrane structure was examined over a wide range of parameters, such as pore size range of substrate and its surface properties, pH of GO dispersion, GO content, synthesis pressure, operating pressure and temperature. The results show that the GO content does not hold a linear relationship with the permeance and selectivity. Film thickness, aggregates, synthesis pressure defects and interlayer spacing have significant effects on the gas separation performance of GO membranes which originate from the synthesis method and its conditions.     

Stabilized gas combustion wave in an inert porous medium

A stabilized gas combustion wave in an inert porous medium with intense internal interphase heat exchange (at low velocities) is considered to elucidate the mechanism underlying the increase in the burning velocity of the homogeneous gas mixture due to the porous medium. It is shown that the major factor of the increase in the burning velocity is conductive heat recuperation from the postflame zone to the region of the fresh mixture through the solid skeleton of the porous medium. Analytical dependences of the degree of increase in the burning velocity of the mixture in the stabilized wave on the determining parameters are obtained. The possibilities and restrictions of the use of the results to analyze the operation of porous burners are discussed. __________ Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 5, pp. 8–15, September–October, 2008.     

Towards a cleaner natural gas production: recent developments on purification technologies

ABSTRACT

The development of new, efficient and cost-effective technologies for acid gases (CO₂ and H₂S) removal from natural gas is pertinent for cleaner energy productions. The removal of acid gases from natural gas can be carried out using different techniques (chemical, physical or hybrid). Although the widely employed techniques are generally effective, they have some ascribed drawbacks such as process efficiency and high-energy cost. Emerging techniques are being considered to reduce or eliminate these limitations but their deployment on an industrial scale may require that certain scientific and technological criteria, such as higher selectivity and gas separation kinetics, be met. Unprecedented and lacking in previous appraisals, this review has focused on the emerging and sustainable developments on acid gases removal from natural gas, but not without a critical evaluation of the existing technologies to provide a better background on the subject, ascertain the status-quo and identify gaps for further improvements. Efficiency of these emerging technologies are analysed with focus on ionic liquids and their blends, binding organic liquids, enzyme-based separation technologies and others. This review also features the brief contribution of the authors towards the development of low-cost materials for CO₂/natural gas separation. This article is expected to serve as an in-depth requisite background for further research on carbon capture processes with respect to natural gas purification.     

板式换热器在天然气净化装置中的应用

板式换热器具有体积小、重量轻、换热效率高等特点,可大大降低装置的能耗、操作费用,取得了较好的经济效益。本文结合工厂实际,比较了管壳式换热器和板式换热器的优缺点,主要介绍了新型板式换热器在天然气净化装置中的应用。     

甲醇装置（以煤焦或重油为原料）的原料气净化

简要介绍国内外甲醇生产原料气净化的现状，综述以煤焦或重油为原料的甲醇装置原料气脱碳、脱硫及脱除其他有害组分的方法，并对我国甲醇生产原料气净化方法的选择提出某些看法和建议．