制氮机空分膜组件综合使用效果测试平台设计

为优化制氮机空分膜组件的综合使用效果,设计了一个测试平台,通过该测试平台,确定最佳产氮效果对应的各位置参数,为膜空分制氮机的设计提供依据。

空分膜组件的使用效果与其联接方式间的关系

从串联与并联的角度 ,对不同联接方式下的空分膜组件的使用效果进行了比较 .在试验数据分析的基础上 ,发现复合型空分膜组件的使用效果跟其联接方式有关 ,在产氮纯度较高时 ,串联的效果明显优于并联的 ,但对于均质型空分膜则不成立 ;同时要求在采用串联时 ,须综合考虑温降和压降的影响 .

膜空分制氮过程稳定性影响因素试验研究

通过试验观察与分析,发现膜空分制氮过程的稳定性除受进气压力和进气温度的主要影响之外,还受膜的工作背压的影响,不过背压只有达到一定值时,才表现出其影响.另外工作过程的压力突然变化会导致产氮纯度的急剧变化,并对这种系统的设计提出一些建议.

液货船、化学品船防爆系统关键设备──膜空分制氮机的研制

本文概述了膜空分制氮原理和主要研究内容。着重对空气预处理技术、膜组件以及膜组件连接方式对整体使用效果的影响进行了试验研究，通过对试验数据的分析和处理，获得了膜组件各参数之间的关系及结论，为样机及以后的设计提供了试验数据和理论依据。最后完成了膜组件的选型、样机的设计和试制，样机的技术性能达到了专题合同规定的指标。

膜空分制氮系统在某补给船上的应用

本文详细介绍膜空分制氮系统在某补给船上的应用,主要包括惰性气体保护、液位测量、扫线功能的设计思路和设计方法.

膜空分制氮系统及其在船舶上的应用

本文从船舶惰性气体防爆系统在军/民用船舶上有很广阔的发展和应用前景出发,介绍了几种常用的制氮设备和方法,重点为先进的膜空分制氮技术及其自行开发的MKF膜空分制氮装置。

膜分离制注氮设备在采气厂的应用研究

近年来氮气在油气田的应用越来越广泛,主要应用于气体钻井、石油三采、油/气管道吹扫,气体钻井过程中,氮气用量特别大、用时长。与传统的液氮应用比较,膜分离制氮具有机动性好、可移动、连续供氮的特点。因此,特别适宜于气体钻井、油气三采、管道吹扫等,发展膜分离制注氮设备在采气厂的应用很有必要。基于此,本文在分析膜分离制氮的原理、流程基础上就膜分离制氮装置在采气厂的应用进行了阐述。

膜间差异和总气进出位置对其并联效果之影响

同一批空分膜组件性能也总有差异,平面式并联方式被广泛采用,为了弄清并联时总气进出口位置和膜组件间的性能差异对其使用效果有无影响,特展开试验研究.试验数据分析表明,不论空分膜组件间的性能有无差异,平面并联时总气进出位置对其产氮效果有影响,在膜组件之外的同一侧时产氮效果最好,浓度高时比在最差位置时的产氮效果提高10%以上,且其变化都会导致各膜组件的产氮浓度和流量的变化,但最终并联结果有的变而有的不变;立体(均布)并联并不比平面并联的好,工程设计上不必考虑这种方式;空分膜组件间的性能差异相对越大,优者被劣者性能抑制越严重,并联的实际结果离理想的越远,尤其是在产氮浓度高时更显著.

Scale-up of NaA zeolite membranes on α-Al_2O_3 hollow fibers by a secondary growth method with vacuum seeding

NaA zeolite membranes were prepared by secondary growth method on the outer surface of α-Al2O3 hollow fiber supports. Vacuum seeding method was used for planting zeolite seeds on the support surfaces. Hydrothermal crystallization was then carried out in a synthesis solution with molar ratio of Al2O3：SiO2：Na2O：H2O = 1：2：2：120 at 100 ℃ for 4 h. Effects of seeding conditions on preparation of hollow fiber NaA zeolite membranes were extensively investigated. Moreover, hollow fiber membrane modules with packing membrane areas of ca. 0.1 and 0.2 m2 were fabricated to separate ethanol/water mixture. It is found that the thickness of seed layer is obviously affected by seed suspension concentration, coating time and vacuum degree. Close-packing seed layer is required to obtain high-quality membranes. The optimized seeding conditions （seed suspension mass concentration of 0.5%-0.7% coating time of 5 s and vacuum degree of 10 kPa） lead to dense NaA zeolite layer with a thickness of 6-8 gin. Typically, an as-synthesized hollow fiber NaA zeolite membrane exhibits good pervaporation performance with a permeation flux of 7.02 kg· m^- 2· h^- 1 and separation factor 〉 10000 for sepa- ration of 90%; （by mass） ethanol/water mixture at 75 ℃ High reproducibility has been achieved for batch-scale production of hollow fiber NaA zeolite membranes by the hydrothermal synthesis approach.

CO2/CH4 separation using inside coated thin film composite hollow fiber membranes prepared by interfacial polymerization

Carbon dioxide(CO_2) is greenhouse gas which originates primarily as a main combustion product of biogas and landfill gas. To separate this gas, an inside coated thin film composite(TFC) hollow fiber membrane was developed by interfacial polymerization between 1,3–cyclohexanebis–methylamine(CHMA) and trimesoyl chloride(TMC). ATR-FTIR, SEM and AFM were used to characterize the active thin layer formed inside the PSf hollow fiber. The separation behavior of the CHMA-TMC/PSf membrane was scrutinized by studying various effects like feed gas pressure and temperature. Furthermore, the influence of CHMA concentration and TMC concentration on membrane morphology and performance were investigated. As a result, it was found that mutually the CHMA concentration and TMC concentration play key roles in determining membrane morphology and performance. Moreover, the CHMA-TMC/PSf composite membrane showed good CO_2/CH_4 separation performance. For CO_2/CH_4 mixture gas(30/70 by volume) test, the membrane(PD1 prepared by CHMA 1.0% and TMC 0.5%) showed a CO_2 permeance of 25 GPU and the best CO_2/CH_4 selectivity of 28 at stage cut of 0.1. The high CO_2/CH_4 separation performance of CHMA-TMC/PSf thin film composite membrane was mostly accredited to the thin film thickness and the properties of binary amino groups.

Synergistic action of non-solvent induced phase separation in preparation of poly(vinyl butyral) hollow fiber membrane via thermally induced phase separation

A systematic study of air gap distance effects on the structure and properties of poly(vinyl butyral)hollow fiber membrane via thermally induced phase separation(TIPS)has been carried out.The results show that the hollow fiber membrane prepared at air gap zero has no skin layer; the pore size near the outer surface is larger than that near the inner surface; and the special pore channel-like structure near the outer surface is formed,which is quite different with the typical sponge-like structure caused by TIPS and the finger-like structure caused by non-solvent induced phase separation(NIPS),because of the synergistic action of non-solvent induced phase separation at air gap zero.The pore size gradually decreases from outer surface layer to the intermediate layer,but increases gradually from intermediate layer to the inner surface layer.With the increase of air gap distance,the pore size near the outer surface gets smaller and a dense skin layer is formed,and the pore size gradually increases from the outer surface layer to the inner surface layer.Water permeability of the hollow fiber membrane decreases with air gap distance,the water permeability decreases sharply from 45.50×10-7 to 4.52×10-7 m3/(m2·s·kPa)as air gap increases from 0 to 10 mm at take-up speed of 0.236 m/s,further decreases from 4.52×10-7 to 1.00×10-8 m3/(m2·s·kPa)as the air gap increases from 10 to 40 mm.Both the breaking strength and the elongation increase with the increase of air gap distance.The breaking strength increases from 2.25 MPa to 4.19 MPa and the elongation increases from 33.9% to 132.6% as air gap increases from 0 mm to 40 mm at take-up speed 0.236 m/s.

Effects of F127 on Properties of PVB/F127 Blend Hollow Fiber Membrane via Thermally Induced Phase Separation

Hydrophilic poly(vinyl butyral)(PVB) /Pluronic F127(F127) blend hollow fiber membranes were prepared via thermally induced phase separation(TIPS) ,and the effects of blend composition on the performance of hydrophilic PVB/F127 blend hollow fiber membrane were investigated.The addition of F127 to PVB/polyethylene glycol(PEG) system decreases the cloud point temperature,while the cloud point temperature increases slightly with the addition of F127 to 20%(by mass) PVB/F127/PEG200 system when the concentration of F127 is not higher than 5%(by mass) .Light scattering results show that the initial inter-phase periodic distance formed from the phase separation of 20%(by mass) PVB/F127/PEG200 system decreases with the addition of F127,so does the growth rate during cooling process.The blend hollow fiber membrane prepared at air-gap 5mm,of which the water permeability increases and the rejection changes little with the increase of F127 concentration.For the membrane prepared at zero air-gap,both water permeability and rejection of the PVB/F127 blend membrane are greater than those of PVB membrane,while the tensile strength changes little.Elementary analysis shows that most F127 in the polymer solution can firmly exist in the polymer matrix,increasing the hydrophilicity of the blend membrane prepared at air-gap of 5mm.

Effect of Diluent on the Morphology and Performance of IPP Hollow Fiber Microporous Membrane via Thermally Induced Phase Separation

Isotactic polypropylene （iPP） hollow fiber microporous membranes were prepared using thermally induced phase separation （TIPS） method. Di-n-butyl phthalate （DBP）, dioctyl phthalate （DOP）, and the mixed solvent were used as diluents. The effect of α （DOP mass fraction in diluent） on the morphology and performance of the hollow fiber was investigated. With increasing α, the morphology of the resulting hollow fiber changes from typical cellular structure to mixed structure, and then to typical particulate structure. As a result, the permeability of the hollow fiber increases sharply, and the mechanical properties of the hollow fiber decrease obviously. It is suggested that the morphology and performances of iPP hollow fiber microporous membrane can be controlled via adjusting the compatibility between iPP and diluent.

Cluster Analysis of Differentially Expressed Heat Stress Genes in Rat Jejunal Mucosal

[Objective] The aim was to study the heat stress mechanism of differen tially expressed genes in rat jejunal mucosal.[Method] Variable cluster analysis and cluster analysis of samples on the differentially expressed heat stress genes in rat jejunal mucosal were carried out with SAS software,and statistics of distribution of the differentially expressed genes on chromosomes were conducted.[Result] The differentially expressed genes were divided into seven categories,of which,the upregulated genes included three categories （i.e.：Category A：Hspa1a,Hspa1b,Hspb1,Hsph1,Dnaja4,Ahsa2 and P4ha1; Category B：Cyp1a2,Zbtb16,Gucy2g,Fgb,Cyp4a3 and Etv2; and Category C：Cyp1a2,Chac1 and Cyp4b1） and the down-regulated genes included four categories （i.e.：Category D：Tlr2,Noxo1,LOC286989 and Aspg; Category E：RGD1560395,Alb and BQ194726; Category F：Ccl4,Gzmk,Al228153,Anxa10,S100a9 and Ascl5; and Category G：Reg1a and Slc13a1）.The classification,function and reasons of differential expression for each gene category were analyzed.[Conclusion] Most of the three categories of up-regulated genes were related to the heat shock proteins; and most of the four categories of down-regulated genes were related to the immunity,providing reference for discussion of the heat stress mechanism.

Separation performance of horizontal and vertical polyethersulfone hollow fiber UF modules

The effect of hollow fiber module positions （ horizontal and vertical） on separation performance for PVA solution by using polyethersulfone （PES） hollow fiber ultrafiltration （UF） membrane with the molecular weight cut-off （MWCO） 30 000 has been discussed. Experimental results illustrated that the suitable operation conditions for PVA solution were as follows： trans-membrane pressure 2.1 bar, solution temperature 75℃ and feed velocity 0.32 m/s. Under these suitable operation conditions, the permeate flux is from 36.8 L/（m^2 ·h·bar） to 42.9 L/（m^2 ·h·bar） for the horizontal module and from 39.8 L/（m^2 ·h·bar） to 66.6 L/（m^2 ·h·bar） for the vertical module. Besides, the Separation performance of PES hollow fiber UF membrane was better by using vertical hollow fiber module than by using horizontal hollow fiber module. When the trans-membrane pressure increased from 1 bar to 2.1 bar, solution temperature from 50 ℃ to 75 ℃, feed solution velocity from 0.16 m/s to 0.32 m/s, the PVA rejection would increase from 95.8% to 99.7%, 95.4 96 to 98.6 %, 95.8 96 to 99.2 96 for horizontal module respectively, and from 98.8 96 to 99.8 %, 98.6 96 to 99.4 96, 98.5 96 to 99.4 96 for vertical module respectively. Therefore, PVA rejection in PES hollow fiber UF process was more than 98.5 96 for vertical module, and it is suitable for PVA recovery from wastewater.

Evaluation of hollow fiber T-type zeolite membrane modules for ethanol dehydration

This work presents the design of hollow fiber T-type zeolite membrane modules with different geometric configurations. The module performances were evaluated by pervaporation dehydration of ethanol/water mixtures. Strong concentration polarization was found for the modules with big membrane bundles. The concentration polarization was enhanced at high temperature due to the higher water permeation flux. The increase of feed flow could improve water permeation flux for the membrane modules with small membrane bundle.Computational fluid dynamics was used to visualize the flow field distribution inside of the modules with different configurations. The membrane module with seven bundles exhibited highest separation efficiency due to the uniform distribution of flow rate. The packing density could be 10 times higher than that of the tubular membrane module. The hollow fiber membrane module exhibited good stability for ethanol dehydration.

Spacial Distribution Characteristics, Activity and Degradation Capability of the Biofilm in Integrated Vertical-flow Constructed Wetland

The spacial distribution characteristics, activity and degradation capability of the biofilm in integrated vertical-flow constructed wetland were investigated. Results showed that the biofilm widely distributed in the substrate of integrated vertical-flow constructed wetland and mainly in the 0-10 cm top layer where the activity ofdehydrogenase of the biofilm was also higher than that of other layers. The water quality could also affect the activity of the biofilm, for the TF（1,3,5-Triphenylformazan） amount reduced by the biofim incubated in water of the higher eutrophication was larger, too. The PCP （pentachlorophenol） removal rate by the substrate with biofilm was 1.5 times that without biofilm. In total, the biofilm of the down-flow chamber appeared larger biomass, higher dehydrogenase activity and stronger degradation capability of organic contamination than that in up-flow chamber and it was the major place for removal of the organic matters in waste water.

3000m^3／h氮气工艺选择及定价分析

本文对大化集团有限责任公司空分为某项目提供的3000m^3／h的氮气进行制氮工艺的选择及供氮价格的取值进行分析，为大化集团有限责任公司空分供氮价格设备的选型及双方的合作做好准备。

Surgery for posttraumatic syringomyelia:a retrospective study of seven patients

Objective： To analyze retrospectively the clinical symptoms, signs, radiological findings and results of treatment of posttraumatic syringomyelia. Methods： The data of 7 patients with posttraumatic syringomyelia confirmed by computerized tomography （CT） and magnetic resonance imaging （MRI） in our hospital between 1999 and 2004 were reviewed retrospectively. The patients underwent decompressive laminectomy or syringo-subarachnoid （S-S） shunting with microsurgery. Long-term follow-up was available （range： 13-65 months）. Results： The major dinical manifestations of posttraumatic syringomyelia usually included the onset of increasing signs and the development of new symptoms after an apparently stable period. The clinical symptoms included pain, sensory disturbance, weakness, and problems in autonomic nerves. Syrinx existed merely at the cervical level in 4 cases and extended downward to the thoracic levels in the other 3 cases. One case underwent decompressive laminectomy, 6 cases were treated by S-S shunting. During the early postoperative period, all the patients showed an improvement of symptoms of syrinx without major complication or death. The decreased size or collapse of the syrinx was demonstrated by postoperative MRI. Conclusions ： Posttraumatic syringomyelia is a disabling sequela of spinal cord injury, developing months to years after spinal injury. MRI is the standard diagnostic technique for syringomyelia. The patients with posttraunmtic syringomyelia combined with progressive neurological deterioration should be treated with operations. S-S shunting procedure is effective in some patients with posttraumatic syringomyelia. Decompressive procedure may be an alternative primary surgical treatment for patients with kyphosis and cord compression.