Performance evaluation of a solarized gas turbine system integrated to a high temperature electrolyzer for hydrogen production

In this paper, the performance of a solar gas turbine (SGT) system integrated to a high temperature electrolyzer (HTE) to generate hybrid electrical power and hydrogen fuel is analyzed. The idea behind this design is to mitigate the losses in the electrical power transmission and use the enthalpy of exhaust gases released from the gas turbine (GT) to make steam for the HTE. In this context, a GT system is coupled with a solar tower including heliostat solar field and central receiver to generate electrical power. To make steam for the HTE, a flameless boiler is integrated to the SGT system applying the SGT extremely high temperature exhaust gases as the oxidizer. The results indicate that by increasing the solar receiver outlet temperature from 800 K to 1300 K, the solar share increases from 22.1% to 42.38% and the overall fuel consumption of the plant reduces from 7 kg/s to 2.7 kg/s. Furthermore, flameless mode is achievable in the boiler while the turbine inlet temperature (TIT) is maintained at the temperatures higher than 1314 K. Using constant amounts of the SGT electrical power, the HTE voltage decreases by enhancing the HTE steam temperature which result in the augmentation of the overall hydrogen production. To increase the HTE steam temperature from 950 K to 1350 K, the rate of fuel consumption in the flameless boiler increases from 0.1 m/s to 0.8 m/s; however, since the HTE hydrogen production increases from 4.24 mol/s to 16 mol/s it can be interpreted that the higher steam temperatures would be affordable. The presented hybrid system in this paper can be employed to perform more thermochemical analyses to achieve insightful understanding of the hybrid electrical power-hydrogen production systems.     

燃料电池空气电极的孔道结构调控

燃料电池是将化学能转化成电能的装置，其空气电极催化层的设计，既要包含丰富的、易于接近的反应活性位，也要具备高度连通的电子、质子以及反应物、产物传质通道，因此电极必须具有特定三维几何结构形貌和有序分布的各功能化孔道，确保催化活性位得以充分利用以及反应可以连续进行。针对催化剂孔道的几何结构调控，本文调研了最近报道的一系列研究工作，从模板法、高温相变法、模板/相变复合方法以及基于金属有机框架材料进行孔道设计等四种主要方法出发，综述了该领域的最新研究进展。     

水泥联合（半终）粉磨系统管磨机一仓仓长的探讨

在水泥管磨机前应用高效率料床粉磨设备辊压机或外循环立磨预处理工艺的前提下,根据配置不同分级机分级后的入磨物料颗粒粒径、易磨性、综合水分及熟料温度等工艺参数,后续管磨机必须选择相对科学合理的仓位比例,以实现磨内磨细与水泥颗粒的整形。磨内各仓有效长度参数能否合理选取,对管磨机段产量、质量与系统粉磨电耗影响较大,这个具有普遍性的问题,在生产过程中往往容易被忽视。由于一仓粗粉碎(磨)能力是决定管磨机系统产量的重要因素之一,而系统产量与粉磨电耗关系密切,故一仓有效长度L1的选择极其重要。在被磨材料特性、磨前预处理工艺及磨内配置与研磨体级配、水泥成品细度相对稳定的条件下,若管磨机一仓选用的有效仓长L1比例参数不合理,在系统运行过程中,一般都会出现共性问题:磨头进料端"冒灰"、"溢料"及磨内一仓"饱磨"现象,主电机运行电流明显下降,不得不采取减料或止料或调整运行参数,使系统长期处于低产量状态运行,粉磨电耗居高不下。实践中,应根据系统不同分级设备、不同工艺等因素科学确定管磨机一仓有效长度。     

Preparation of hydrophobic flat sheet membranes from PVDF-HFP copolymer for enhancing the oxygen permeance in nitrogen/oxygen gas mixture

In this study, poly(vinilydene fluoride-co-hexafluoropropylene)(PVDF-HFP) was used for preparation of hydrophobic membranes using non-solvent induced phase inversion(NIPS) technique. PVDF-HFP copolymer with concentrations of 10 wt% and 12 wt% was prepared to investigate the effect of polymer concentration on pore structure,morphology, hydrophobicity and performance of prepared membranes. Besides, the use of two coagulation baths with the effects of parameters such as coagulant time, polymer type and concentration, and the amount of nonsolvent were studied. The performance of prepared membranes was evaluated based on the permeability and selectivity of oxygen and nitrogen from a gas mixture of nitrogen/oxygen under operating conditions of feed flow rate(1–5 L·min~(-1)), inlet pressure to membrane module(0.1–0.5 MPa) and temperatures between 25 and 45 °C. The results showed that the use of two coagulation baths with different compositions of distillated water and isopropanol,coagulant time, polymer type and concentration, and the amount of non-solvent additive have the most effect on pore structure, morphology, thickness, roughness and crystallinity of fabricated membranes. Porosity ranges for the three fabricated membranes were determined, where the maximum porosity was 73.889% and the minimum value was 56.837%. Also, the maximum and minimum average thicknesses of membrane were 320.85 μm and115 μm. Besides, the values of 4.7504 × 10~(-7) mol· m~(-2)· s~(-1)· Pa~(-1), 0.525 and 902.126 nm were achieved for maximum oxygen permeance, O_2/N_2 selectivity and roughness, respectively.     

煤磨热风管道改造的效果

中联万基水泥有限公司4500t/d熟料生产线采用SCLW4-12×13.4第四代篦冷机,煤磨热风取风口和余热发电AQC热风取风口在篦冷机同一对称位置,煤磨与余热发电系统存在争风现象,开停煤磨对余热发电系统影响较大。通过从废气管道处开孔,加装管道和电动阀,与热风管道汇合通往煤磨沉降室,调整相应阀门开度,可以控制入煤磨烟气温度,这样不但提高了余热发电量,而且提高了煤磨产量,同时也降低了窑头排风机的负荷,降低了熟料生产电耗。     

Improving outdoor air quality based on building morphology: Numerical investigation

Due to rapid urbanization around the world, high concentrations of vehicular pollutants have deteriorated the outdoor air quality, which can affect the physical and psychological well-being of humans. Numerous strategies have been proposed to overcome these harmful impacts by improving the dispersion of air pollutants. Consequently, a question arises regarding the potential effects of building morphology on the dispersion of pollutants. Subsequently, transient three-dimensional Computational Fluid Dynamics (CFD) simulations are performed to examine the effect of building morphology on PM₁₀ dispersion. Eleven cases with various prototypes and morphological methods are compared with a simple building form to identify the patterns of PM₁₀ dispersion within a given time sequence under a prevailing inflow condition. The results indicate that the different designs of building morphology with varying Relative compactness (R_C) indicator highlight the importance of considering morphological factors to improve outdoor air quality. In addition, the proposed prototypes can reduce PM₁₀ concentrations by approximately 30%–90% at specific points in the studied time sequence. In particular, the vertical, horizontal, and grid folded prototypes can be considered more effective as an approximate decrease between 70% and 90% in PM₁₀ concentrations is observed, which reflects the influence of building morphology on improving outdoor air quality.     

基于永磁涡流传动的长距离带式输送机启动特性研究

针对矿用带式输送机启动过程易出现打滑、淤带和断带等问题,基于永磁涡流传动技术,将双盘式磁力耦合器作为带式输送机的驱动装置,建立双盘式磁力耦合器动态数学模型,运用AMEsim软件搭建带式输送机系统仿真模型,设置启动时间分别为60、80和100 s,采用Harrison控制曲线启动时,研究带式输送机满载启动时机头、机尾部输送带的速度特性和张力特性,张紧装置位移特性以及双盘式磁力耦合器调速气隙特性,仿真结果表明:当启动时间为60 s时,带式输送机输送带速度波动大,动张力明显,尾部输送带最大张力达到29 kN,启动过程不平稳;双盘式磁力耦合器调速时,气隙变化与带式输送机启动速度变化趋势相反,启动过程气隙从22 mm减小到4 mm;当启动时间为80 s和100 s时,带式输送机启动过程相对平稳,速度和张紧装置位移波动小,尾部输送带张力波动幅度分别为5 kN和3 kN;带式输送机启动过程存在最佳启动时间,继续延长时间,对带式输送机启动特性影响越来越小,80 s可作为合理启动时间。     

特种车辆舱室送风系统布局仿真优化

特种车辆由于其功能特殊性和封闭性，无法像民用车辆一样利用窗户的开闭来控制舱室通风，长时间驾驶特种车辆，驾驶舱面临空间小、冷源少、热负荷大、缺乏新鲜空气等问题，且外部环境条件复杂。这就要求特种车辆舱室送风系统精细设计，满足人员和多个装置的热舒适和热控需求，因此有必要基于特殊车辆的驾驶舱特点，合理布局并优化通风系统，保证整舱热要求。为了让座舱送风与舱内热源热交换尽量完全，带出更多的热量，首先针对某型特种车辆，建立了典型舱室和乘员的三维物理模型和仿真模型。针对10种送风模式进行了详细的气流组织仿真优化分析，获得了特种车辆舱室多物理场。气流组织优化是从风口形式和送风口位置两方面进行，风口形式优化中提出多种风口组合形式，分别进行仿真。以设备温控、人员热舒适和空气龄等为目标，利用评价函数对仿真结果进行评价，对10种类型的送风工况进行了仿真。从仿真结果中，以上述多优化目标为依据，进一步开展了针对初步优选的送风形式的风口位置优化。在风口形式优化结果的基础上，采用遗传算法，将位置参数设为优化参数，选取两个评估函数作为优化的目标函数，并将头足温差等约束条件设置到优化模型中，对仿真结果进行筛选和逆优化研究，最终得到最优风口位置，完成气流组织优化。研究对于全密封特种车辆的有限空间热舒适性和空气质量研究具有一定意义。     

Associations between evaporative cooling and dust‐mite allergens,endotoxins, and β‐(1 → 3)‐d‐glucans in house dust: A study of low‐income homes

Recent work suggests that evaporative coolers increase the level and diversity of bioaerosols, but this association remains understudied in low‐income homes. We conducted a cross‐sectional study of metropolitan, low‐income homes in Utah with evaporative coolers (n = 20) and central air conditioners (n = 28). Dust samples (N = 147) were collected from four locations in each home and analyzed for dust‐mite allergens Der p1 and Der f1, endotoxins, and β‐(1 → 3)‐d ‐glucans. In all sample locations combined, Der p1 or Der f1 was significantly higher in evaporative cooler versus central air conditioning homes (OR = 2.29, 95% CI = 1.05‐4.98). Endotoxin concentration was significantly higher in evaporative cooler versus central air conditioning homes in furniture (geometric mean (GM) = 8.05 vs 2.85 EU/mg, P < .01) and all samples combined (GM = 3.60 vs 1.29 EU/mg, P = .03). β‐(1 → 3)‐d ‐glucan concentration and surface loads were significantly higher in evaporative cooler versus central air conditioning homes in all four sample locations and all samples combined (P < .01). Our study suggests that low‐income, evaporative cooled homes have higher levels of immunologically important bioaerosols than central air‐conditioned homes in dry climates, warranting studies on health implications and other exposed populations.