纳米颗粒强化胺法吸收CO2研究进展

碳捕集、利用与封存（CCUS）技术是缓解全球气候变化的重要措施之一。纳米颗粒因具有良好表面效应和体积效应,能够强化CO2捕集传质性能而备受青睐,其可增大胺法吸收CO2过程中的传质系数并减少溶剂再生所需的能量,有望进一步提高CO2捕集效率、降低能耗。本文从纳米颗粒强化胺法吸收CO2过程出发,讨论了纳米颗粒强化吸收的3种机理（抑制气泡聚并机理、传输机理、边界层混合机理）,总结了近年来国内外最新研究进展,论述了纳米颗粒强化CO2吸收过程中的主要影响因素,指出纳米颗粒对CO2吸收过程的强化是多重因素共同作用的结果,并对该技术的未来研究方向作了展望。     

稠油火驱二次点火主控因素及点火策略

为了实现火驱开发过程中熄火油层再次燃烧,保障火驱开发效果,通过一系列室内物理模拟实验和油藏数值模拟计算,开展包括点火温度、通风强度、地下含油饱和度分布、结焦带等影响二次点火的主控因素的研究,给出了合理的二次点火温度和通风强度的范围,同时结合注气井地下空气腔规模给出了不同条件下启动油层二次燃烧的点火策略.结果表明,电点火温度应控制在450 ℃以上,点火期间通风强度应维持在10 m³/(m²·h)以上,对于需要注燃料油进行二次点火的注气井,燃料油的用量不低于已燃区空气腔体积的2/7.     

基于流固耦合的闸板防喷器建模及有限元分析

为了更加准确地分析流体对闸板剪切力的影响规律,需要对闸板防喷器剪切钻杆进行流固耦合分析。以钻杆窜动和扭转2种动态工况为例,利用SolidWorks建立闸板防喷器三维模型,并对防喷器内部流体域进行有限元建模,输出到ANSYS Fluent进行有限元分析。结果表明:在闸板剪切钻杆过程中,流体达到稳态后,在钻杆窜动工况下,流体力随钻杆受载荷力增大而减小; 在钻杆扭转工况下,流体力随钻杆扭转角度而变化,在扭转90°时流体力最大。研究结果可为防喷器剪切闸板的剪切能力分析及结构设计提供参考。     

碳纳米纤维增强聚甲醛复合材料制备及性能

通过纳米碳纤维(CNFs)在聚甲醛(POM)基体中的均匀分散以及取向,制备了具有优异力学性能和热性能的POM/CNFs复合材料。利用扫描电子显微镜、透射电子显微镜、拉伸性能测试、热重分析、动态热机械分析测试表征了POM/CNFs复合材料的结构和力学、热学性能。结果表明,CNFs与POM分子链形成氢键相互作用,促进了CNFs在POM基体内分散,同时使POM/CNFs复合材料的结晶度显著提高。随着CNFs含量增加,POM/CNFs复合材料的拉伸强度、储能模量和损耗模量均得到提高。当添加0.5%的CNFs时,拉伸强度、储能模量及损耗模量分别提高了20.5%,127%和58%。进一步研究了高温拉伸对POM/CNFs复合材料性能的影响。结果表明,CNFs沿拉伸方向定向排列,同时复合材料拉伸后结晶度提高,拉伸强度显著增加。     

A compact cryogenic pump

A centrifugal cryogenic pump has been designed at Argonne National Laboratory to circulate liquid nitrogen (LN₂) in a closed circuit allowing the recovery of excess fluid. The pump can circulate LN₂ at rates of 2–10 L/min, into a head of 0.5–3 m. Over four years of laboratory use the pump has proven capable of operating continuously for 50–100 days without maintenance.     

Does moving towards renewable energy cause water and land inefficiency? An empirical investigation

This study investigates the effect of renewable energy production on water and land footprint in 58 developed and developing countries for the period of 1980–2009. Utilizing the ecological footprint as an indicator, the fixed effects, difference and system generalized method of moment (GMM) approaches were employed and eight different models were constructed to achieve robustness in the empirical outcomes. Despite the use of different methods and models, the outcome was the same whereby GDP growth, urbanization, and trade openness increase the water and land footprint. Moreover, renewable energy production increases the water and land inefficiency because of its positive effect on ecological footprint. Additionally, based on the square of GDP it is concluded that the EKC hypothesis does not exist while the square of renewable energy production indicates that renewable energy production will continue to increase water and land footprint in the future. From the outcome of this study, a number of recommendations were provided to the investigated countries.     

气藏采收率影响因素研究与启示——以靖边气田A井区为例

以鄂尔多斯盆地靖边气田A井区为例，采用单因素相关分析和数值模拟方法，对比研究了井网控制程度、储层物性及地层废弃压力对气藏采收率影响及其主次关系。结果表明，井网控制程度是影响采收率的首要因素，井网控制程度每增加10%，采收率提高8.5%；渗透率是影响采收率的重要因素，渗透率每增加10%，采收率平均增加6%；废弃压力对采收率亦有较大影响，废弃压力每降低10%，采收率可提高1.6%。三者对采收率影响综合排序为：井网控制程度>储层物性>废弃压力。分析认为，渗透率是储层固有属性，很难从根本改变；而废弃压力受井口外输压力和增压开采成本制约，降低幅度有限。因此，优化井网及增加井网控制程度是提高气藏采收率的有效途径。研究成果具有实践意义，可为改进气田开发方式和提高气藏采收率提供参考。     

Dynamic response of underground gas storage salt cavern under seismic loads

A dynamic elastoplastic damage constitutive model is proposed based on the failure characteristic of rock salt under seismic loads. The coding of the proposed model is achieved by the embedded FISH (short for FLACish) language of FLAC^3D (Fast Lagrangian Analysis of Continua). Numerical models of bedded salt cavern gas storage facilities in China are developed by using FLAC^3D, and the proposed constitutive model is used in the simulations. The effects of seismic input angle, seismic acceleration, seismic moment, types of seismic waves, and gas pressure on the dynamic response, stress, displacement, plastic zone, and safety factor (SF) of rock masses that surround salt cavern gas storage facilities are studied. Results show that the seismic wave perpendicular to the surface poses the greatest risk to the safety of the cavern. With an increase in seismic acceleration, the cavern’s SF decreases and that of the lower structure of the cavern decreases more than that of the upper section. Plastic zones propagate from the cavern’s internal surface to the pillar, and then to the pillar and floor along the right and left corners of the cavern bottom. Higher internal gas pressure improves cavern safety. The acceleration and duration of seismic waves are critical factors in ensuring the safety of the cavern. The SF of the cavern’s lower structure is more sensitive to changes in seismic parameters than that of the other locations, which makes the cavern bottom more likely to be destroyed during an earthquake. Therefore, the lower structure should be the study target in the seismic design for a salt cavern gas storage facility. Results have been used in the seismic design of salt cavern gas storage facilities in China.     

One-step fabrication of N-doped TiO2 inverse opal films with visible light photocatalytic activity

N-doped TiO₂ inverse opal films were fabricated by a novel method through one-step coassembly of polymer colloidal spheres and titania precursor. This coassembly approach removed the need of preassembled colloidal crystal for precursor solution infiltration and respective chemicals for titania formation and nitrogen doping. Less crack films with well ordered inverse opal structure could be produced by adding appropriate amount of TiBALDH (titanium(IV)-bis-lactato-bis-ammonium dihydroxide) into the precursor solution. The films prepared at the optimized condition showed enhanced visible light photocatalytic activity, which could be attributed to both the N doping effect and their unique inverse opal structure.