Studies on urethane–allophanate networks based on hydroxyl‐terminated polybutadiene: Modeling of network parameters and correlation to mechanical properties

Hydroxyl‐terminated polybutadiene (HTPB)‐based allophanate–urethane networks were prepared by reacting HTPB with di‐isocyanates, such as toluene–di‐isocyanate (TDI), isophorone–di‐isocyanate (IPDI), and 4,4′‐di(socyanatocyclohexyl)methane (H₁₂MDI) at stoichiometric ratios (r‐values) ranging from 1.0 to 1.5. The networks were characterized for mechanical and swell properties. The network parameters, such as “X,” which is the fraction of urethane groups involved in the allophanate formation, and effective chain length (L_x) were calculated from experimental crosslink density values determined from swell data, using α‐model equations developed by Marsh. Excellent linear correlations were obtained between mechanical properties and the calculated network parameters. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2986–2994, 2006     

Catalyst Design of Pt-Modified Ni/Al2O3 Catalyst with Flat Temperature Profile in Methane Reforming with CO2 and O2

Pt(0.3)/Ni(10)/Al₂O₃, prepared by a sequential impregnation method, exhibited a more excellent performance in methane reforming with CO₂ and O₂ in terms of the catalytic activity and the temperature profile of the catalyst bed than Pt(0.3) + Ni(10)/Al₂O₃ prepared by a coimpregnation method, Ni(10)/Al₂O₃, Pt(0.3)/Al₂O₃, and Pt(10)/Al₂O₃. It is thought that this is because the surface Pt atoms on Ni catalyst can contribute to the enhancement of the catalyst reducibility.     

Direct conversion of methane to higher hydrocarbons via an oxygen free,low-temperature route

The direct conversion of methane to higher hydrocarbons over a silica-supported Ru catalyst has been investigated via an oxygen free, two-step route. The reaction consists of decomposition of methane over a 3% silica-supp orted Ru catalyst at temperatures between 400 and 800 K to produce surface carbonaceous species followed by rehydrogenation of these species to higher hydrocarbons at of 368 K. It was found that the Ru/SiO₂ catalyst exhibits a trend similar to that for single-crystal Ru catalysts. However, the temperature at which a maximum in ethane selectivity occurs shifts toward a higher temperature. It was also found that the ethane yield can be optimized by changing the surface carbon coverage. Under optimum conditions a net ethane yield of about 13–15% has been realized. For this two-step reaction sequence, only a few reaction cycles could be operated without intermediate high temperature rehydrogenation and without significant loss in ethane yield. This is attributed to large amounts of inactive carbon that could not be hydrogenated at 368 K. Higher methane partial pressures were found to be desirable for this reaction. The activity of the catalyst could also be maintained at total pressures up to 10 atm.     

郑庄东大井区煤层含气量主控地质因素

以郑庄区块东大井区为主要研究对象,综合运用实验测试数据、煤田钻孔及煤层气井资料,并结合沉积、构造和地下水动力的原理和方法,深入分析了该区煤层含气量分布和主控地质因素。研究结果表明:研究区煤层含气量较高,总体呈自东向西逐渐增大的趋势,且主要受煤层埋藏深度、地质构造和水动力条件三个因素控制。即煤层埋深对含气量分布具有较好的控制作用,总体上含气量高值区大都位于北部深埋区域;地质构造对含气量的影响主要表现为次级构造叠加在煤层埋深影响的总体背景之上导致含气量展布复杂化;北部地区水动力条件对煤层气的运移和富集具有显著的控制作用,是影响煤层含气量展布的主要因素;而南部地区则由于埋深和断层等因素的影响,从而导致水动力条件与煤层含气量的相关性不太明显。     

沁水盆地郑庄煤层气储层裂隙的测井响应特征

煤层气储层的裂隙发育程度与储层的地球物理测井响应特征相关,通过对沁水盆地郑庄区块80余口井测井资料的分析,总结了地质构造作用及裂隙发育对测井特征的影响,认为研究区识别煤层气储层裂隙的敏感参数依次为体积密度（DEN）、深侧向电阻率（RD）、声波时差（AC）、井径（CAL）、自然伽马（GR）、中子孔隙度（CNL）等,通过判断深、中、浅三个电阻率值的差异识别裂隙发育程度,建立了夹矸层RD≥3000 Ω·m、3000Ω·m＞RD≥1000Ω·m、1000Ω·m＞RD≥500Ω·m、RD＜500Ω·m、及CNL＞ 45％等几种类型的测井响应参数,给出了相应的测井响应示例,为建立研究区的裂隙发育展布提供了参考.     

GJT25-09型煤层气专用固井半挂车研制

煤层气勘探开发井的钻井深度浅、固井作业压力低、水泥浆用量少,使用常规固井设备时操作复杂、经济性不高。采用一体化结构设计,实现固井车的混浆单元、泵送单元、供灰单元、供气单元的集成设计。利用“双泵合流-双马达串/并联切换”技术,实现设备全液压驱动,开发了煤层气专用固井半挂车,并介绍了该车的技术参数、技术与结构特点、测试应用情况。可对煤层气固井作业起到较好的降本增效作用,对煤层气的大力开发提供支持。     

Intensification of low-grade methane enrichment in nitrogen mixture by CH4/CO2 displacement

To solve the problem of CO₂ uncompleted desorption in the process of CO₂ displacement enhancing the adsorption separation of CH₄/N₂, a small amount of product gas CH₄ was used as purge gas to improve the CO₂ desorption. CH₄/CO₂ mixture gas obtained from desorption step was recycled as the displacement gas to enhance the enrichment of low-grade methane in nitrogen mixture. In this work, the research conducted the experiments for CH₄/N₂ separation using CH₄/CO₂ displacement intensification adsorption and the laboratory-made coconut shell activated carbon as sorbent. The mathematical models were built in gPROMS and the accuracy of models was verified by comparison of simulations and CH₄/N₂/CO₂ breakthrough experiments. The performance of enrichment of low-grade methane with displacement intensification using different displacer was compared. The result showed that the process with CH₄/CO₂ displacement had higher purity product than CO₂ displacement. The CH₄/ CO₂ mixed gas replacement enhanced vacuum pressure swing adsorption cycle experiment was carried out, which can jointly enrich 14% CH₄/ N₂ and 53% CH₄/CO₂ to 98.8%, and at the same time obtain a recovery rate of 77.8%.     

便携式多气体检测仪设计

介绍一种便携式多气体检测仪的设计方案,使用PIC18LF6620作为核心处理器,同时连续检测O2、CO、H2S、CH4四种气体的浓度。详细介绍了气体传感器工作原理及其信号处理电路。经过实际测试,该检测仪具有体积小、重量轻、灵敏度高、响应速度快、测量精确等优点。     

一种低功耗的无线瓦斯传感器节点设计

在对比常用瓦斯传感元件的基础上,选择了OPTOSENSE公司最新生产的红外吸收式甲烷气体传感器MIPEX,设计了无线瓦斯传感器节点硬件电路。在ZigBee协议栈的基础上,设计节点软件程序。节点处于周期约为10min的工作/休眠交替状态,在3节普通电池供电的情况下,从理论上估计其工作时间可超过10年之久,是采用传统低功耗瓦斯传感元件所远远不能达到的。