共查询到20条相似文献，搜索用时 515 毫秒
1.
首先综述了目前MTP工艺中循环烃的作用,然后从MTP反应的机理出发,对循环烃所起的作用进行了分析。结果表明,循环烃的加入对于MTP工艺丙烯选择性和丙烯收率的提高有着积极的影响,C2循环中乙烯含量的增加有益于提高丙烯收率,C4循环烃能够抑制反应向生成C4的方向进行,C5/C6循环烃有利于生成丙烯的前体或者有利于抑制副反应的进行。 相似文献
2.
3.
4.
哈尔滨石化分公司气柜丙烯回收系统始建于1994年,有一台处理能力为600立方米/小时的丙烯压缩机.近几年随着聚丙烯装置处理能力的扩大,原有的一台丙烯压缩机每天24小时不停机,有时带病运行,很难满足安全生产,同时由于存在处理能力瓶颈,会有大量丙烯低压气体并入到碳四柜中,影响了公司的经济效益.针对这一问题,通过对丙烯回收系统进行增容改造,将处理能力提高至1500立方米/小时,即解决了系统瓶颈,又消除了安全隐患,同时公司的丙烯回收量也有大幅度的增加. 相似文献
5.
6.
本篇文章着重针对气分装置所涉及到的化工工艺流程进行了全面深入的分析,同时对于其中其中导致丙烯收率被影响的因素加以研究,以期通过提升操作形式以及优化系统吸收稳定性的方式,来直接促使气分装置表现出的丙烯收率得以提升。 相似文献
7.
采用ADV微分浮阀对气分装置的脱丙烷塔、脱乙烷塔和精丙烯塔进行技术改造,在三塔的塔径、塔高和塔盘数不变的情况下,将气分装置的处理量由50Kt/a提高到100Kt/a,丙烯纯度达到99.5%以上。 相似文献
8.
9.
10.
11.
The chaos characteristics of melt index have been first explored, and the Hilbert–Huang transform method and time delay embedding method are applied to multiscale dynamic analysis on the time series of the melt index (MI) in the propylene polymerization industry. The research results show that the embedding delay is 2, the embedding dimension is 5, the correlation dimension D2 is 1.57, and the maximum Lyapunov exponent is 0.143 for the melt index series, which provide clear evidence of chaotic multiscale features in the propylene polymerization process. Three intrinsic mode functions (IMFs) are decomposed from the melt index time series; the presence of non-integer fractal correlation dimension and positive finite maximum Lyapunov exponent are found in some IMF components. The PP melt index series are divided into two chaotic signals, a determined signal and a random signal respectively, and its complexity is therefore reduced. Furthermore, the coupling of subscale structures of the propylene polymerization is explored with the dimension of interaction dynamics and a robust algorithm for detecting interdependence. It is found that IMF(2) is the main driver in the coupling system of IMF(1)and IMF(2). All these provide a guideline for studying propylene polymerization process with chaotic multiscale theory and may offer more candidate tools to model and control propylene polymerization system in the future. 相似文献
12.
We present facile strategies for the fabrication of two types of microfluidic devices made of hydrogels using the natural biopolymers, alginate, and gelatin as substrates. The processes presented include the molding-based preparation of hydrogel plates and their chemical bonding. To prepare calcium-alginate hydrogel microdevices, we suppressed the volume shrinkage of the alginate solution during gelation using propylene glycol alginate in the precursor solution along with sodium alginate. In addition, a chemical bonding method was developed using a polyelectrolyte membrane of poly-L-lysine as the electrostatic glue. To prepare gelatin-based microdevices, we used microbial transglutaminase to bond hydrogel plates chemically and to cross-link and stabilize the hydrogel matrix. As an application, mammalian cells (fibroblasts and vascular endothelial cells) were cultivated on the microchannel surface to form three-dimensional capillary-embedding tissue models for biological research and tissue engineering. 相似文献
13.
通过表面引发原子转移自由基聚合技术(SI-ATRP)使聚甲基丙烯酸甲酯(PMMA)接枝于有序介孔氧化硅(MCM41)粒子的孔道内外表面,制得表面PMMA接枝的MCM41复合粒子(MCM41-g-PM-MA)。进一步利用增塑剂碳酸丙烯酯(PC)与所得的MCM41-g-PMMA共同对PMMA基聚合物电解质膜进行改性,通过溶液浇铸工艺制得PMMA基复合型聚电解质膜。着重考察了MCM41-g-PMMA填充比例、MCM41表面PMMA接枝以及温度等因素对上述体系离子电导率的影响。红外光谱(FTIR)、热重(TGA)、高倍透射电镜(HRTEM)、小角X射线衍射(SAXRD)分析结果表明:PMMA已成功接枝于MCM41粒子的孔道内外表面。交流阻抗测试、差示扫描量热分析(DSC)表明:较改性前的MCM41填充体系,MCM41-g-PMMA填充的PMMA膜具有更优的离子电导率,同时具有更佳的热稳定性能。 相似文献
14.
不同药剂处理对低温逆境下烟草种子发芽和幼苗生长的影响 总被引：3，自引：0，他引：3
研究了不同药剂处理对低温逆境下不同耐寒力烟草品种种子发芽和幼苗生长的影响。采用不同浓度的外源脯氨酸、水杨酸、氯化钙、甘油、二甲基亚砜、乙二醇、聚乙二醇、丙二醇、烯效唑、脱落酸对不同耐寒力烟草品种种子浸种处理后,测定了低温逆境下不同烟草品种发芽及幼苗生长和生理生化指标变化。结果表明,脯氨酸、水杨酸、氯化钙、二甲基亚砜和聚乙二醇5种药剂浸种能显著促进烟草种子发芽,提高了低温逆境下幼苗根长、苗高、幼苗干鲜重以及超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性,其中10 g/L脯氨酸、120 mg/L水杨酸、15 mg/L氯化钙、30 ml/L二甲基亚砜和100 ml/L聚乙二醇综合效果较好,可以作为提高烟草种子及幼苗抗寒性的处理方法。 相似文献
15.
从分子水平研究了PEO-PPO-PEO嵌段共聚物聚集过程中分子基团微环境和构象的变化。FTIR光谱给出了温度、溶剂、嵌段共聚物组成等影响PEO-PPO-PEO嵌段共聚物胶团结构的定量信息。用无机盐和脂肪醇调控PEO-PPO-PEO嵌段共聚物聚集，荧光光谱技术提供了降低PPO链段与水的相互作用，推动嵌段共聚物在水中胶团化的证据。用水凝胶包埋PEO-PPO-PEO嵌段共聚物，实现了萃取水中低浓度多环芳烃的工艺循环。 相似文献
16.
《Electronic Journal of Biotechnology》2014,17(2):72-78
Background1,3-Propanodiol (1,3-PD), is used in the production of polytrimethylene terephthalate (PTT), an aromatic polyester that exhibits high elastic recoveries. It is also employed as a supplement with low solidification properties, a solvent and a lubricant in the formof propylene glycol. 1,3-PD is effectively synthesized by a microbiological way from crude glycerol. The main problem of this technology is using a high concentration of glycerol, which is a limiting factor for bacteria cells growth (especially in batch fermentation).ResultsIn this work, the influence of different glycerol concentration in batch fermentation on Clostridium butyricum DSP1 metabolism was investigated. The biomass was concentrated for two times with the use of membrane module (in case of increasing kinetic parameters). Increased optical density of bacteria cells six times increased the productivity of 1,3-PD in cultivation with 20 g/L of glycerol at the beginning of the process, and more than two times in cultivation with 60–80 g/L. Also the possibility of complete attenuation of 140 g/L of crude glycerol in the batch fermentation was investigated. During the cultivation, changes of protein profiles were analyzed. The most significant changes were observed in the cultivation in the medium supplemented with 80 g/L of glycerol. They related mainly to the DNA protein reconstructive systems, protective proteins (HSP), and also the enzymatic catalysts connected with glycerol metabolic pathway.ConclusionsThe application of filtration module in batch fermentation of crude glycerol by C. butyricum DSP1 significantly increased the productivity of the process. 相似文献
17.
草乌中有毒生物碱的提取分离 总被引：2，自引：0，他引：2
针对药材中乌头碱、中乌头碱、次乌头碱的提取分离方法进行了研究,本方法提取回收率与碱性苯溶液提取方法相似.方法中所用试剂成本低毒性小,适用于乌头碱、中乌头碱、次乌头碱的提取分离以及对照品的制备。 相似文献
18.
19.
松脂蒸馏的方法有滴水法、水蒸汽法、导热油法和CO2/N2循环活气法,从能量消耗、过程装备、产品质量以及"三废"排放等方面,对各种松脂蒸馏方法进行比较。结果表明,CO2/N2循环活气法比水蒸汽法节省能量消耗近一倍,减少冷却水用量13.23~16.18m3/t松香;CO2/N2循环活气法蒸馏松脂不需要油水分离器、盐滤器,又因为不需要带走活气的冷凝热,冷凝冷却器的换热面积也减少,也不需要建造大型过热水蒸汽锅炉;CO2/N2循环活气法蒸馏松脂所得的产品不含水份,松香无结晶现象,松节油透明无混浊;而且该法蒸馏松脂无三废产生,克服了水蒸汽法排放含松节油废水、废气和工业废盐的缺点,是一种清洁的生产方法。 相似文献
20.
提出一种研究高能点火互感电路过渡过程的新方法。通过对磁介质磁化曲线采用数理统计方法拟合，找出拟合函数，然后运用四阶龙格－库塔法求解微分方程。文中求出初级电流瞬态解，同时给出PSPICE软件仿真结果。 相似文献