采用高斯模型分析输气管道泄漏后气体的扩散

在深入分析输气管道泄露气体扩散的基础上,根据天然气扩散本身的特征和研究问题的需要,采用高斯模型确定了泄漏源有效高度,天然气扩散系数,高度与风速的关系。指出：泄漏源抬升高度与扩散气体的初始速度和方向、初始温度、泄漏口直径、环境风速的关系;扩散系数的大小与大气湍流结构、离地面高度、地面粗糙度、泄漏持续时间、抽样时间间隔、风速以及离开泄漏源的距离等因数的关系;风压高度变化系数和高度的函数关系。     

Effect of Hydrocarbon and Non‐Hydrocarbon Gas Injection on the Interfacial Tension of a Gas Condensate System

Experimental results of interfacial tension (IFT) of condensate‐brine‐gas systems over a pressure range of 1000 to 8000 psi and a temperature range of 95 to 160 °C are presented. High‐pressure high‐temperature video‐enhanced pendent drop tensiometry was established to capture drop images for IFT measurements at various reservoir thermodynamic conditions. This paper serves as a building block to the essential practical understanding of the surface effects associated with improved condensate recovery from gas condensate reservoirs by gas injection. This understanding is critical for ascertaining gas injectivity, displacement and trapping in the pore spaces, and potential geological storage of CO₂.     

弓形降液管内的气含率分布

采用毛细管不我电检测技术，测定了弓形降液管内气含率的三维分布。实验结果表明，在降液管中心处的气含率高于两侧，在外侧的气含率高于内仙。沿高度方向气含率的分布分为三个区：第一区为高气含率区，第二区为气含率显著变化区，第三区为下层低气含率区。在每一区内，气含率都随液体流率的增加而增加。研究结果为设计更合理的降这提供了实验依据。实验还表明Ｈｏｆｈｕｉｓ关于乳化态的据是有局限性的。     

Thermodynamic Analysis of Solid Oxide Fuel Cell Gas Turbine Systems Operating with Various Biofuels

Solid oxide fuel cell–gas turbine (SOFC‐GT) systems provide a thermodynamically high efficiency alternative for power generation from biofuels. In this study biofuels namely methane, ethanol, methanol, hydrogen, and ammonia are evaluated exergetically with respect to their performance at system level and in system components like heat exchangers, fuel cell, gas turbine, combustor, compressor, and the stack. Further, the fuel cell losses are investigated in detail with respect to their dependence on operating parameters such as fuel utilization, Nernst voltage, etc. as well as fuel specific parameters like heat effects. It is found that the heat effects play a major role in setting up the flows in the system and hence, power levels attained in individual components. The per pass fuel utilization dictates the efficiency of the fuel cell itself, but the system efficiency is not entirely dependent on fuel cell efficiency alone, but depends on the split between the fuel cell and gas turbine powers which in turn depends highly on the nature of the fuel and its chemistry. Counter intuitively it is found that with recycle, the fuel cell efficiency of methane is less than that of hydrogen but the system efficiency of methane is higher.     

The Formulation Design and Performance Test of Gas Generators Based on Guanidinium Azotetrazolate

Six types of gas generators based on guanidinium azotetrazolate (GZT) were designed into six formulations having different oxidants: GZT‐LiNO₃ (1), GZT‐NaNO₃ (2), GZT‐KNO₃ (3), GZT‐Mg(NO₃)₂ (4), GZT‐Sr(NO₃)₂ (5) and GZT‐KMnO₄ (6), respectively. The properties of these formulations were investigated in terms from gas production, appropriate combustion temperature and nontoxic gaseous emission. REAL software calculation program [1] was used to calculate the combustion heat at constant pressure, combustion heat at constant volume and specific volume in standard state. It showed that gas generators based on GZT with nitrate salts as oxidant exhibited better performance. Thus its thermal behavior and combustion temperature were studied further and the experimental results were consistent with the theoretical calculation results. Therefore, it can be concluded that formulation 3 has comprehensive optimal performance: low moisture content, insensitivity to friction, heightened vacuum stability, high combustion heat and specific volume. Namely, formulation 3 exhibited the most promising indications of commercial application, such as using in air bags of motor vehicles.     

Further Studies of the Gas Penetration Process in Gas‐Assisted Injection Molding

Abstract

Gas‐assisted injection molding is one of the innovation injection‐molding processes recently developed. The solution of gas penetration thickness interface is the key problem in the simulation of gas‐assisted injection molding, but also the puzzle. By applying the matching asymptotic expansion method, an analytical solution of the gas penetration interface is deduced. First, the governing equations and boundary conditions are transformed to be dimensionless. And then matching asymptotic expansion method is applied to solve the dimensionless equations, where capillary number Ca and Ca ^2/3 are used as perturbation parameters. Compared with experimental results, the presented mathematical model and solving method are proved to be correct.     

Gas backmixing in the dense region of a circulating fluidized bed

The gas backmixing characteristics in a circulating fluidized bed (0.1 m-IDx5.3-m high) have been determined. The gas backmixing coefficient (D_ba) from the axial dispersion model in a low velocity fluidization region increases with increasing gas velocity. The effect of gas velocity onD _ba in the bubbling bed is more pronounced compared to that in the Circulating Fluidized Bed (CFB). In the dense region of a CFB, the two-phase model is proposed to calculate D_bc from the two-phase model and mass transfer coefficient (k) between the crowd phase and dispersed phase. The gas backmixing coefficient and the mass transfer coefficient between the two phases increase with increasing the ratio of average particle to gas velocities (U_p/U_g).     

磷肥生产中含氟废气吸收利用的途径

阐述了磷肥含氟废气的产生及危害,通过分析比较磷肥含氟废气吸收净化采用不同吸收剂得到的副产物,制备氟化物产品的工艺方法,提出了选择磷肥含氟废气吸收净化以稀氟化铵溶液、氨水为吸收剂,再制备氟化物产品的工艺技术路线,氟化物产品纯度高,生产装置简单,能耗低,费用低,是制备氟化物产品的有效途径。     

陶瓷业发生炉煤气脱硫探讨

简要介绍陶瓷业发生炉煤气的制备及煤气中的硫化氢和危害,重点探讨发生炉煤气的湿法脱硫和干法脱硫的工艺方法、技术路线,并简要分析不同工艺技术的特点和经济合理性。     

富县地区中生界浅层气主要成藏地质因素研究

富县研究区是鄂尔多斯盆地油气勘探程度相对较低的一个地区。通过对研究区浅层气烃源条件、储层特征、盖层、圈闭等主要成藏地质因素进行分析,认为研究区处于生烃中心,油源充足;储集空间发育;气藏类型主要为岩性、构造一岩性圈闭;受静压力、动压力、水动力作用、扩散作用、毛细管作用等的影响,研究区中生界浅层气运聚的主要通道为古侵蚀面、砂体、断层或微裂缝。     

气体辅助注塑成型技术

介绍一种新的塑料加工技术——气体辅助注塑成型技术的工艺过程和设备配置，分析了其成型特点和典型应用。根据气辅成型的不同工艺过程，可分为标准成型法、副腔成型法、熔体回流法和活动型芯法四种。气辅成型所用设备包括注塑机、气辅装置、进气喷嘴等。其特点是所需注射压力小、制品翘曲变形小、可消除缩痕，提高表面质量、适用于成型壁厚差异较大的制品、在不增加制品重量的情况下可增加制品的刚度和强度、对一般制品可通过气体的穿透，减轻重量，缩短成型周期。典型的应用是制作刷柄、扶手、方向盘等棒形或管形件，汽车仪表盘等大的板形件，厚薄不均的各种家电外壳和塑料家具等。     

长输天然气管道燃机热耗率计算与校正方法研究

以天然气为燃料的燃机作为压缩机驱动源在长输天然气管道行业中普遍使用,特别是性价比较高的航改型燃机。燃机的效能作为天然气管道优化运行的重要指标之一受到普遍关注,掌握燃机组在实际运行中的性能对天然气管道运行人员,特别是运行方案制定人员至关重要。针对长输天然气管道的燃机效能最重要指标--热耗率的计算与校正的一整套方法进行阐述和研究,并与厂家提供的效能图和实际运行数据进行了比较,证明该方法能使燃机的主要效能参数误差控制在5%以内,满足了实际生产人员和优化仿真人员的工作需要。     

Gas Fermentation Expands the Scope of a Process Network for Material Conversion

Biotechnological fermentation is a well-established process, however, it is far from being fully understood and exploited. A new area of fermentation technology that has evolved over the recent decades is gas fermentation. Many microorganisms have been reported in literature to be capable of utilizing a variety of gases such as CO, CO₂, H₂, and CH₄ under anaerobic or aerobic conditions as their main carbon and/or energy source. Mostly waste stream gases from industrial plants or those that can be produced via the gasification of solids are investigated. This review focuses on the currently available scientific knowledge about gas fermentation processes, particularly anaerobic syngas fermentation and aerobic methane fermentation. Gas fermentation processes are compared with aerobic and anaerobic fermentation processes based on dissolved solid substrates. Also, the potential of gas fermentation when integrated into a biotechnological network of processes is outlined.     

基于Taguchi方法优化气辅成型气体穿透深度

基于气体辅助注塑成型过程的三维数值模拟,利用Taguchi实验方法设计了L9(34)实验矩阵,采用标准方差分析方法,分析了预注射量、注射温度、气体压力和延迟时间等工艺因素对气体穿透深度的影响,预测了优化工艺组合下的气体穿透深度。研究表明:在所选择的工艺因素中,对气体穿透深度影响程度依次为预注射量(F=87.8%)、气体延迟时间(F=8.1%)、气体压力(F=3.5%)和注射温度(F=0.6%)(F为因子重要性)。在优化工艺组合下预测的气体相对穿透深度为87.1%,与模拟计算值符合较好。     

Gas film formation time and gas film life time during electrochemical discharge phenomenon

The formation of a gas film around an electrode is at the origin of the electrochemical discharges in aqueous solutions and in molten salts. The study of the electrochemical discharge phenomenon from the current signal point of view is conducted to identify the gas film formations and the following discharges. This is performed using the wavelet analysis as a denoising tool with the discrete Meyer wavelet as base function. The proposed algorithm allows to measure experimentally the gas film life time and its necessary building time prior to each series of discharges. The accuracy of the algorithm is evaluated using generated signals and its application to real data is demonstrated. From the experimental data, it is concluded that the gas film is more stable at high terminal voltages whereas its formation time decreases with it. Electrochemical and thermal interpretations for the measured statistics are proposed.     

Gas transport in tight porous media: Gas kinetic approach

We describe the flow of gas in a porous medium in the kinetic regime, where the viscous flow structure is not formed in separate pores. Special attention is paid to the dense kinetic regime, where the interactions within the gas are as important as the interaction with the porous medium. The transport law for this regime is derived by means of the gas kinetic theory, in the framework of the model of “heavy gas in light one”. The computations of the gas kinetic theory are confirmed by the dimension analysis and a simplified derivation revealing the considerations behind the kinetic derivation. The role of the thermal gradient in the transport law is clarified.     

煤制合成天然气发电系统技术和前景分析

对优质天然气资源需求的不断增加以及价格的高涨使得以煤为原料生产合成天然气技术引起了人们的普遍关注。笔者对典型的煤制合成天然气技术进行了分析,与高效发电技术相结合,提出了基于SNG的新型发电系统（包括SNG-电联产调峰系统和IGFC系统）,分析了SNG发电系统的特点和发展前景。     

Gas transport behavior of semicrystalline syndiotactic polystyrene containing α and β crystalline forms

Solid-state structure of syndiotactic polystyrene (s-PS) after crystallization from the melt and the glassy state was examined by differential scanning calorimetry, density and X-ray diffraction analysis (WAXS). It was possible to prepare semicrystalline s-PS containing pure α (α″ or α′ modifications) and pure β crystalline forms with different crystallinities (0-40%). The measurements confirmed the low density of both crystalline forms, which in the case of α crystalline form was smaller and in the case of β crystalline form was slightly larger than the density of the glassy amorphous s-PS. Oxygen and carbon dioxide gas permeability, diffusion and solubility of semicrystalline s-PS containing different crystalline forms were studied as a function of crystallinity. These measurements confirmed that more dense β crystalline form was impermeable for the transport of small gas molecules while less dense α crystalline form was highly gas permeable. Unusual gas transport behavior of the α crystalline form was attributed to porous crystalline structure containing the nanochannels. Despite the porous structure, α crystalline form showed very low oxygen and carbon dioxide solubility compared to gas solubility in the amorphous phase. The proposed diffusion model explained the characteristic features of the gas permeation behavior for chemically ‘inert’ small gas molecules in the permeation medium consisting of glassy amorphous polymer with dispersed porous crystalline phase containing the nanochannels. A new relaxation process with the maximum at about −35 °C was observed in semicrystalline s-PS containing the α crystals and was associated with the porous structure of this crystalline form.     

伊通岔路河西北缘凝析气藏体积压裂技术研究与应用

伊通地堑岔路河断陷西北缘为低孔低渗致密凝析气藏,勘探主力储层埋藏深(2 000~4 000 m)、闭合应力梯度高(0.018~0.024 MPa/m)、温度高(95~150℃);储层伊蒙混层粘土矿物含量高,喉道细小;存在水敏、反凝析及"水锁"伤害,制约产能。常规压裂技术压后返排率低、产能低或无效果。采用复合压裂体积改造技术,通过高排量大液量低表界面、高防膨性能滑溜水造缝增加孔隙压力,提高地层能量同时形成复杂裂缝网络,降低水敏、水锁、反凝析现象,提高气体由基质向裂缝渗流的通道;并集成组合支撑、套管压裂等多项技术进行高排量大液量体积改造技术研究,现场应用2口井2层,施工成功率100%,压后返排率80%。