专业技术培训中现场教学的组织与实施

现场教学作为教学与实践相互促进、相互转化、有机结合的重要途径,包含了选择现场教学企业、设计教学内容、现场教学管理、现场讲解人员选择、教学研讨、信息保密等要素和环节。专业技术培训的现场教学对引导培训对象挖掘技术领域深层次问题具有良好的效果。现场教学实践活动有助于加深对现场教学规律的认识,使培训机构获得更多的企业培训经验。     

超高分子量聚丙烯酰胺在造纸中的应用

近些年来 ,超高分子量聚丙烯酰胺由于其在絮凝方面的优良性能正逐渐受到人们的重视。本文就超高分子量聚丙烯酰胺在造纸上的应用和价格分析作一简要介绍 ,并预测 ,超高分子量聚丙烯酰胺的发展前景相当广阔     

大牛地气田DK25井腐蚀分析与防治

通过对中国石油化工股份有限公司中原油田分公司大牛地气田DK25井水样和气样化验分析和电磁探伤分析,表明该井存在井下管柱腐蚀.通过对模拟试验的腐蚀产物和腐蚀因素进行分析,表明咪唑啉类复配缓蚀剂(C/D2)对该井具有较好的防护效果,其缓蚀率可达86 %左右.     

催化精馏合成丙烯酸乙酯研究

以阳离子交换树脂(Amberlyst-15wet)为催化剂,在自制精馏塔和精制塔内对催化精馏酯化合成丙烯酸乙酯工艺进行了研究。考虑到后续丙烯酸乙酯的纯化,实验过程中丙烯酸过量,保证乙醇尽可能转化。实验中以捆扎包作为催化剂装填方式,系统研究了空速、催化精馏塔回流比、进料酸醇摩尔比等因素对乙醇转化率和产品中丙烯酸乙酯含量的影响,获得的较佳工艺条件:空速为0.35m3/(m3.h),酸醇进料摩尔比为2∶1,催化精馏塔回流比为2。该工艺条件下,乙醇转化率为96.96%,产品中丙烯酸乙酯含量为97.08%。     

重油催化裂化反应系统结焦的治理

1　前　言荆门石油化工总厂 80 0 kt/a重油催化裂化装置 ,掺炼减压渣油 2 0 %～ 35%,加上丙烷脱沥青油实际掺渣量达 30 %～ 4 5%,其反应 -再生系统为两器高底并列、重叠式两段再生 ,自 1 996年投产以来几次发现在反应系统的沉降器和提升管等部位均有一定程度的结焦 ,经治理取得了明显的效果。2　结焦概况反应系统结焦的主要部位在提升管进料喷嘴的上方区域、反应沉降器的顶部区域、旋风分离器的内升气管和料腿翼阀、反应汽提段。2 .1　第一次结焦在 1 997年 1月第一次小修时发现 ,提升管进料下喷嘴油流切线方向有厚约 50 mm、宽约 30 0 mm的…     

催化重整装置扩能改造方案探讨

以一个炼油厂催化重整装置扩能改造的情况为例,对５种技术上可行的扩能改造方案进行了技术经济分析和对比,指出由于具体的装置规模,产品要求,现场条件及对下游生产装置影响的不同,投资及经济效益也不同。所需改造的装置不宜统一用一种改造方案。     

粘土矿物对砂岩储层损害的影响——回顾与展望

人们一开始就把地层损害与粘土矿物相联系,从20世纪30年代起,经历了发现水敏损害现象、确立分散／运移机制、探索分散／运移规律及防治技术三个阶段,80年代进入全面发展阶段,不断深化损害机理认识,损害诊断和控制技术取得实质性进展,在这一演变过程中分析技术的进步对揭示损害机理起到了重要的促进作用。指出应重视粘土矿物-水相互作用、结构粘土矿物学、粘土矿物-水-原油界面作用方向的研究工作。     

Synthesis and phase transition behavior of undoped VO2 with a strong nano-size effect

The phase transition process from monoclinic VO₂ (B) to monoclinic rutile-type VO₂ (M) nanorods under hydrothermal conditions was explored. VO₂ (M) nanorods were formed by nucleating nanobumps on the surface of VO₂ (B) nanorods and growing them until the VO₂ (B) transformed entirely to VO₂ (M). The metal-semiconductor transition temperature of VO₂ (M) nanobumps exhibited an extremely strong size effect. The critical size for the nano-size effect was determined to be <13.0 nm; below this size, phase transition temperatures were significantly reduced from 68.0 °C for bulk VO₂ (M) to 5.0—17.0 °C and from −14.5 to −11.0 °C for heating and cooling semicycles, respectively. These results are attractive because they indicate a new strategy to regulate the phase transition temperatures purely through the particle size.     

Formation and metal-to-insulator transition properties of VO2-ZrV2O7 composite films by polymer-assisted deposition

VO₂-ZrV₂O₇ composite films were prepared on silica glass substrates by polymer-assisted deposition using a V-Zr-O solution. The coexistence of ZrV₂O₇ and VO₂ was confirmed by Raman spectroscopy, glance angle X-ray diffraction, and X-ray photoelectron spectroscopy. The composite films with similar thickness of about 95 nm showed decreased particle sizes and significantly enhanced luminous transmittances (from 32.3% at Zr/V=0 to 53.4% at Zr/V=0.12) with increasing Zr/V rations. The enhancement in the luminous transmittance was ascribed to the absorption-edge changes in the composite films. This feature benefits the application of VO₂ to smart windows.     

A reduced mechanism for ethylene/methane mixtures with excessive NO enrichment

A detailed mechanism for methane–ethylene mixtures enriched with excessive amount of NO was systematically reduced for efficient numerical simulations of flames in arc-heated co-flowing air. Methane and ethylene were selected as the surrogate fuel in the present study due to their drastically different features of ignition and extinction properties and flame propagation speeds, such that the mixtures of them may be utilized to mimic practical hydrocarbon fuels with various kinetic properties in experiments. The recently released USC Mech-II for C1–C4 was grafted with the NO_x sub-mechanism in GRI-Mech 3.0 with updated reaction parameters for prompt NO formation. The resulting detailed mechanism with 129 species and 900 reactions was first validated against experiments involving NO_x enrichment and reasonably good agreements were observed. The detailed mechanism was then employed as the starting mechanism for the reduction. A skeletal mechanism with 44 species and 269 reactions was derived using the methods of directed relation graph (DRG) and DRG-aided sensitivity analysis (DRGASA); a 39-species reduced mechanism with 35 semi-global reaction steps was further obtained using the linearized quasi steady state approximations (LQSSA). Five species related to prompt NO were retained in the reduced mechanism because of their significant impacts on the fuel oxidation. The reduced mechanism closely agrees with the detailed mechanism for ignition and extinction of homogenous mixtures, as well as selected 1-D flames over a wide range of parameters with NO concentrations between 0% and 3%. The observed worst-case relative error of the reduction is approximately 20%. The reduced mechanism was further validated with experiments involving excessive NO_x enrichment.