聚酰亚胺中空纤维膜的脱湿性能以及在乙醇气相脱水过程中的应 …

采用聚酰亚胺和碘化聚芳醚砜共混改性的中空纤维膜,研究了在不同操作条件下对压缩空气的脱湿性能,并以此作为吹扫气源,研究了在气流吹扫操作方式下蒸汽渗透法乙醇气相脱水过程,实验结果表明,膜的脱水性能与膜材料的亲水性有关,控制共混比例可以得到综合性能优良的气体脱湿膜。     

聚酰亚胺、聚砜、聚醚砜及其共混改性中空纤维膜用于醇/醚气相分离的研究

甲醇／ 甲基叔丁基醚的分离是目前具有实用意义的重要研究课题之一,采用气流吹扫式操作,研究了聚酰亚胺、不同结构的聚砜中空纤维膜在不同操作条件下,对甲醇／ 甲基叔丁基醚气相混合体系的分离性能,也研究共混改性对分离膜性能的影响。结果表明,各种材料的膜具有相近的分离行为,即随着气相中甲醇含量的增加,透过通量逐渐增大而分离系数逐渐减小,聚酰亚胺膜具有适中的透过通量,但具有很高的分离系数,在甲醇浓度低于２０ ％ 时,分离系数可达数千。采用聚醚砜共混改性的聚酰亚胺膜在未明显降低透过通量的条件下,使醇／ 醚分离系数大幅度提高,有很好的应用前景。     

共混改性聚酰亚胺中空纤维膜的压缩空气除湿性能研究

采用干／湿相转换法制备了共混聚酰亚胺中空纤维膜,并对其与聚酢亚胺(PI)中空纤维膜的除湿性能进行了比较,结果表明：在不同压力、不同流量和不同吹扫比例的情况下,共混膜的除湿性能均优于PI膜,特别是增大吹扫比例时,共混膜的优越性更为明显,虽然在抽真空的条件下,共混膜的除湿性能不如采用吹扫操作方式的,但是,同PI膜相比脱湿性能仍然好于PI膜。     

聚酰亚胺,聚砜,聚醚砜及其共混改性中空纤维膜用于醇／醚气？…

甲醇／甲基叔丁基醚的分离是目前具有实用意义的重要研究课题之一,采用气流哆扫式操作,研究了聚酰亚胺、不同结构的聚砜中空纤维膜在不同操作条件下,对甲醇／甲基叔丁基醚气相混合体系的分离性能,也研究共混改性对分离膜性能的影响。结果表明,各种材料的膜具有相近的分离行为,即随着气相中甲醇含量的增加,透过通量逐渐增大而分离系数逐渐减小,聚酰亚胺膜具有适中的透过通量,但具有很高的分离系数,在甲醇浓度低于２０％时,     

聚酰亚胺6FDA-mPDA及其非对称中空纤维膜的气体渗透性能

用两步法制备了聚酰亚胺2,2＇-双（3,4-二羧酸苯基）六氟丙烷二酐（6FDA）-1,3-苯二胺（mPDA）．测定了聚合物致密膜的密度、自由体积分率和玻璃化转变温度．制备了不同干纺距离下具有超薄致密皮层的聚酰亚胺中空纤维膜．制备的中空纤维膜在25℃,0．5MPa下,O2的渗透速率为19．10GPU,O2／N2分离系数为5．99,CO2的渗透速率为106．34GPU,CO2／CH4的分离系数为82．00．致密皮层的厚度约为96nm．考察了操作温度对膜性能的影响,结果表明,随着温度的升高,膜的渗透速率增大,分离系数减小．物理老化对膜性能的实验结果表明,随着老化时间的增加,膜的渗透速率减小,分离系数增大．膜的致密层厚度影响膜的老化性能．     

Matrimid5218/PSf双层非对称中空纤维膜的制备及其气体分离性能研究

以商业化聚酰亚胺Matrimid5218作为功能层材料,聚砜作为支撑层材料,采用共挤出法制备双层非对称中空纤维气体分离膜.所制备的双层非对称中空纤维膜具有致密无缺陷的超薄皮层,致密皮层厚度约为0.21μm.在25℃,0.5 MPa下,CO2/CH4的选择性系数达51.39,CO2的渗透系数为46.29 GPU,O2/N2的选择性系数达到7.13,O2的渗透速率为6.38 GPU.考察了温度和压力对膜的渗透系数和选择性系数的影响,并考察了物理老化对膜性能的影响.     

Matrimid®5218/PSf双层非对称中空纤维膜的制备及其气体分离性能研究

以商业化聚酰亚胺Matrimid®5218作为功能层材料, 聚砜作为支撑层材料, 采用共挤出法制备双层非对称中空纤维气体分离膜. 所制备的双层非对称中空纤维膜具有致密无缺陷的超薄皮层, 致密皮层厚度约为0.21 μm. 在25 ℃, 0.5 MPa下, CO2/CH4的选择性系数达51.39, CO2的渗透系数为46.29 GPU, O2/N2的选择性系数达到7.13, O2的渗透速率为6.38 GPU. 考察了温度和压力对膜的渗透系数和选择性系数的影响, 并考察了物理老化对膜性能的影响.     

添加PVP和涂覆聚合物对PAN基中空纤维炭膜性能的影响

研究了用ＰＡＮ基中空纤维膜为基质制备气体分离用中空纤维炭膜的过程。考察了添加剂ＰＶＰ对炭膜的Ｈ２，Ｎ２气体渗透速率，分离系九和柔韧性的影响。同时，研究了用丙烯腈共聚物对中空纤维炭膜涂覆改性后Ｈ２，Ｎ２气体的渗透速率和分离系数。     

季胺盐对共混聚酰亚胺膜气体除湿性能的影响

季胺盐对共混聚酰亚胺膜气体除湿性能的影响;共混改性;聚酰亚胺;季胺盐;亲水性;除湿     

芳香聚酰亚胺气体分离膜

芳香聚酰亚胺一直在电子、复合材料及粘接剂等领域广泛地应用。最近,聚酰亚胺膜已用于气体的分离过程。这是因为芳香聚酰亚胺是具有高玻璃化温度的玻璃态聚合物,它对小分子比大分子有更大的选择透过性,高选择性是与玻璃态聚合物的僵硬主链,对不同尺寸的分子提供筛分作用相连系的。新开发的芳香聚酰亚胺膜是用联苯四甲酸二酐与芳香二胺缩聚制备的聚酰亚胺溶液制造的。这种中空纤维状的膜是由一个多孔结构支撑的一个很薄的外表面组成的。它可通过聚合物溶液采用干——湿法过程纺丝而成,经溶剂交换干燥,外层的致密部分由计算可知厚度低于0.1μm。它对H_2与CO、CH_4.N_2及其它气体的分离有高度的选择性。由于它具有聚酰亚胺特有的耐高温性能,所以可以在很广的气体加工条件下使用。这种膜对水蒸气有很高的透过性,因而也可用于有机蒸气的脱水,或空气干燥。此膜对水蒸气的透过速度为乙醇的100～200倍。30%的乙醇水溶液,经一次膜分离,浓度可提高到99%。空气干燥系统可产出达到-50℃露点的空气。     

Quantitation of chromatographic peaks in the 0.1 to 1.0% range

Summary This report was conceived as a source for the relations between five pneumatic parameters of carrier gas-inlet and outlet pressure, inlet and outlet velocity, and average velocity. Any pair of these parameters can be independent while the remaining three can be expressed as functions of the independent pair. As the total number of the independent pairs is ten, thirty different functions describing relations between arbitrary independent pairs and dependent parameters can be identified. All thirty were derived below together with the complete set of bounds for variations of independent parameters. To derive some relations, a third order rational equation had to be solved. Some properties of that solution are discussed. A simple case of vacuum operations with zero outlet pressure has also been considered.     

Relations between pneumatic parameters of ideal gas in a column with uniform permeability

Summary This report was conceived as a source for the relations between five pneumatic parameters of carrier gas — inlet and outlet pressure, inlet and outlet velocity, and average velocity. Any pair of these parameters can be independent while the remaining three can be expressed as functions of the independent pair. As the total number of the independent pairs is ten, thirty different functions describing relations between arbitrary independent pairs and dependent parameters can be identified. All thirty were derived below together with the complete set of bounds for variations of independent parameters. To derive some relations, a third order rational equation had to be solved. Some properties of that solution are discussed. A simple case of vacuum operations with zero outlet pressure has also been considered.     

对离子反应发生条件中“放出气体”的再认识

离子反应发生条件中的“放出气体”,与其他资料中对生成物的描述不一致,也与有关反应事实不符。“放出气体”的出现,使教材中对气体生成物的描述时此时彼,没有时序性、规律性。对其与化学反应的关系及其与“生成气体”的区别进行了论述,并提出了修改的建议。     

标准气浓度对定量误差影响的探讨

In the trace gas analysis,experimental results show that the relative error can be kept in the range of±10% even in case where the difference in concentration between the standard mixture and sample gas is up to100 times.When the exponential dilution is used for calibration,the standard mixtures of higher concentra-tion with less period of time in the dilution procedure give quite accurate data.     

Critical evaluation of gas standards based on hydrogen

Summary Six commercial hydrogen standards containing helium, oxygen, nitrogen, methane and carbon dioxide at trace levels were analyzed by gas chromatography, for periods up to 105 days. The concentrations, in the range of 0–120 μmol mol⁻¹, were stable (with the exception of oxygen) but often significantly different from the certified values provided by the suppliers, especially for helium, oxygen and nitrogen. Concurrently, some experiments were carried out to verify the stability of gas mixtures based on hydrogen stored in cylinders submitted to different chemical and physical treatments. The causes that led to the deviations observed, as well as the decreases in oxygen, are discussed. Presented at the 21^st ISC held in Stuttgart, Germany, 15^th–20^th September, 1996.     

Flow of the carrier gas in open-tubular capillary columns in temperature-programmed gas chromatography

A second-order non-linear partial different equation was derived to describe the dependence of carrier gas pressure in the column on the column distance and the time under temperature programmed conditions. This equation was solved numerically by the modified finite difference method for various column parameters. Constant inlet and outlet pressures were used as boundary conditions. The retention times calculated on assumption of a constant pressure profile along the column. Significant differences between retention times of corresponding solutes calculated by the two methods were found, especially when relatively long columns(L>50m) with small internal diameter(d<0.3mm)and high temperature program rates (r>5°/min)are used.     

Theoretical Prediction on the New Types of Noble Gas Containing Anions OBONgO− and OCNNgO− (Ng=He,Ar, Kr and Xe)

The fluorine-less noble gas containing anions OBONgO⁻ and OCNNgO⁻ have been studied by correlated electronic structure calculation and density functional theory. The obtained energetics indicates that for Ng=Kr and Xe, these anions should be kinetically stable at low temperature. The molecular structures and electron density distribution suggests that these anions are stabilized by ion-induced dipole interactions with charges concentrated on the electronegative OBO and OCN groups. The current study shows that in addition to the fluoride ion, polyatomic groups with strong electronic affinities can also form stable noble gas containing anions of the type Y⁻…NgO.     

城市生活垃圾低温热解产气特性的实验研究

用直径200 mm的外热式固定床反应器,以城市生活垃圾中9种典型成分的混合物为实验物料,在300 ℃～700 ℃对其进行了低温热解的实验研究。结果表明,在其他条件相同的情况下,随着热解温度的提高,热解反应所需时间缩短;热解气的总产率、最大瞬时产率均增加;热解气的各成分随温度的升高呈现出不同的变化趋势;热解气的热值在600 ℃达到最大值,为15.13 MJ/m3,可满足民用燃气的要求。     

中日合作废气处理项目分析实验室管理的几点经验

为顺利开展中日合作废气处理项目，中国石油化工股份有限公司环境监测总站建立了废气分析实验室，并完善了质量控制、质量保证体系，这些管理体系包括实验室物资设备的管理，实验室环境，质量保证体系，废气样品采集及实验室分析手段等。为废气处理项目的实施提供了有力的技术支持，并实现了实验室管理的科学化、标准化、规范化。     

Characteristics of Carbon Isotopes of Alkane Components and Identification Marks of Biogenic Gases in China

The carbon isotope composition of alkane component in biogenic gases of China has the following characteristics:with the increase of carbon number of the alkane molecules in biogenic gases, (i) the distribution range of the δ13C values and their main frequency sections become narrower, and both the heaviest and the lightest δ13C boundary values shift to their heavier end; (ii) the δ13C values of ethane and propane in biogenic gases present a positive linear relationship and (iii) the values of δ13C1, δ13C2 and δ13C3 tend to become heavier with the increase of heavy alkane component (C2+3) in biogenic gases. The authors studied the relationship between the δ13C values and the amount of heavy alkane components in biogenic gases (δ13C1 -C2+3(%). δ13C2 -C2+3(%) ,δ13C3-C2+3(%) for the first time and set up the interrelated regression equations between δ13C and C2+3 content (C2+3%), and advance that δ13C1< -55‰ and C2+3<0. 5% are two fine marks for identification of biogenic gases of China. δ13C