Investigation on PEM water electrolysis cell design and components for a HyCon solar hydrogen generator

Hydrogen as a secondary energy carrier promises a large potential as a long term storage for fluctuating renewable energies. In this sense a highly efficient solar hydrogen generation is of great interest especially in southern countries having high solar irradiation. The patented Hydrogen Concentrator (HyCon) concept yields high efficiencies combining multi-junction solar cells with proton exchange (PEM) membrane water electrolysis. In this work, a special PEM electrolysis cell for the HyCon concept was developed and investigated. It is shown that the purpose-made PEM cell shows a high performance using a titanium hybrid fiber sinter function both as a porous transport layer and flow field. The electrolysis cell shows a high performance with 1.83 V at 1 A/cm² and 24 °C working under natural convection with a commercially available catalyst coated membrane. A theoretical examination predicts a total efficiency for the HyCon module from sunlight to hydrogen of approximately 19.5% according to the higher heating value.     

Oxy‐fuel combustion technology: current status,applications, and trends

The increased level of emissions of carbon dioxide into the atmosphere due to burning of fossil fuels represents one of the main barriers toward the reduction of greenhouse gases and the control of global warming. In the last decades, the use of renewable and clean sources of energies such as solar and wind energies has been increased extensively. However, due to the tremendously increasing world energy demand, fossil fuels would continue in use for decades which necessitates the integration of carbon capture technologies (CCTs) in power plants. These technologies include oxycombustion, pre‐combustion, and post‐combustion carbon capture. Oxycombustion technology is one of the most promising carbon capture technologies as it can be applied with slight modifications to existing power plants or to new power plants. In this technology, fuel is burned using an oxidizer mixture of pure oxygen plus recycled exhaust gases (consists mainly of CO₂). The oxycombustion process results in highly CO₂‐concentrated exhaust gases, which facilitates the capture process of CO₂ after H₂O condensation. The captured CO₂ can be used for industrial applications or can be sequestrated. The current work reviews the current status of oxycombustion technology and its applications in existing conventional combustion systems (including gas turbines and boilers) and novel oxygen transport reactors (OTRs). The review starts with an introduction to the available CCTs with emphasis on their different applications and limitations of use, followed by a review on oxycombustion applications in different combustion systems utilizing gaseous, liquid, and coal fuels. The current status and technology readiness level of oxycombustion technology is discussed. The novel application of oxycombustion technology in OTRs is analyzed in some details. The analyses of OTRs include oxygen permeation technique, fabrication of oxygen transport membranes (OTMs), calculation of oxygen permeation flux, and coupling between oxygen separation and oxycombustion of fuel within the same unit called OTR. The oxycombustion process inside OTR is analyzed considering coal and gaseous fuels. The future trends of oxycombustion technology are itemized and discussed in details in the present study including: (i) ITMs for syngas production; (ii) combustion utilizing liquid fuels in OTRs; (iii) oxy‐combustion integrated power plants and (iv) third generation technologies for CO₂ capture. Techno‐economic analysis of oxycombustion integrated systems is also discussed trying to assess the future prospects of this technology. Copyright © 2017 John Wiley & Sons, Ltd.     

A systematic study of photocatalytic H2 production from propionic acid solution over Pt/TiO2 photocatalyst

The propionic acid (HPr) is one of the main by‐products during fermentative H₂ process. To efficiently convert HPr to H₂ gas, photocatalytic H₂ production from HPr solution with the use of Pt/TiO₂ photocatalyst under ultraviolet light has been studied in this research. The Pt/TiO₂ photocatalyst has been prepared by the sol–gel method and further characterized by X‐ray diffraction, TEM and XPS. Effects of Pt loading amount, HPr concentration, initial pH value on photocatalytic H₂ production have been investigated in detail. From practical point of view, the H₂ evolution from HPr solution under UV irradiation for prolonged time has been studied as well. The Langmuir model can be able to describe the relationship between HPr concentration with the maximum rate of H₂ production. The apparent quantum efficiency and apparent energy conversion efficiency are found to 1.65 and 0.72%, respectively. To better understand the photocatalytic H₂ process over Pt/TiO₂, a possible mechanism for the degradation of HPr has been proposed as well. Based on our results, an efficient route for hydrogen production from renewable biomass can be established by coupling biological H₂ production process with photocatalytic H₂ production process. Copyright © 2010 John Wiley & Sons, Ltd.     

毛毛虫形粗旦仿毛锦纶6纤维的生产工艺

对毛毛虫形粗旦仿毛锦纶6的生产工艺进行了研究分析,发现合理控制纺丝速度、纺丝温度、侧吹风、热辊温度和拉伸比等工艺参数,改进上油方式,可以生产出物性指标良好,并具有较好仿毛手感的粗旦仿毛锦纶6FDY。试验表明:纺速在4000~4300m/min,拉伸比1.1~1.3,热拉伸温度150~170℃,侧吹风速0.10~0.18m/s,下调上油位置,延缓上油时间,可以生产出外观好、染色均匀、性能指标好、仿毛手感好的粗旦仿毛锦纶6全拉伸丝。     

Preconditioning approaches related to canonical correlation by use of cyclic form

There are many situations in engineering where we need to calculate the eigensystem of a matrix A which is given as a product of matrices, that is, A = A ₁ A ₂···A _p . Since, usually, we first perform the multiplication of the factors, the matrix A often becomes very ill-conditioned. Actually this happens even when A is a symmetric matrix, which will be our concern here. In this article we introduce a new approach to calculate the eigensystem of A without performing the indicated multiplication, or performing only partially the multiplication of the factors.     

宏远煤矿液压柔掩支架的技术应用

为了解决4.2 m柔掩工钢支架强度有限,在顶板压力大或地质变化时经常造成支架挤架、摞架、架斜等现象给安全生产带来的重大安全隐患。宏远煤矿大胆尝试采用ZRY36/45L型柔性液压支架采煤工艺,结果表明采用该液压支架后保证了工作面的安全生产,生产效率得到了较大的提高,促进了安全高效矿井的建设。     

发射药连续化生产模型研究

为研究发射药连续化生产技术,以发射药溶塑制造工艺为背景,建立发射药连续化生产模型.利用制造发射药的物料在工序中的流动速度,研究了发射药连续化生产各工序物流匹配关系和工艺设备匹配关系,通过对发射药连续化生产工艺单元物料流速进行分析,建立了发射药连续化生产线物料流速为特征的发射药连续化生产模型,并以某种发射药制造为例研究发射药连续化生产模型在该发射药连续化生产中的应用.结果表明:该模型可用于发射药连续化生产工艺优化,解决离散工序与连续工序的连续化结合问题.     

A reactive decision-making approach to reduce instability in a master production schedule

One of the primary factors that impact the master production scheduling performance is demand fluctuation, which leads to frequently updated decisions, thereby causing instability. Consequently, global cost deteriorates, and productivity decreases. A reactive approach based on parametric mixed-integer programming (MIP) is proposed that aims to provide a set of plans such that a compromise between production cost and production stability is ensured. Several stability measures and their corresponding MIP model are proposed. An experimental study is performed to highlight the effectiveness of the reactive approach with regard to the proposed performance measures. It is observed that an improvement in stability does not mean a significant increase in the total production cost. Furthermore, the procedure yields a set of plans that in practice would enable flexible management of production.     

Hydrogen production and End-Uses from combined heat,hydrogen and power system by using local resources

To address the problem of fossil fuel usage at the Missouri University of Science and Technology campus, using of alternative fuels and renewable energy sources can lower energy consumption and hydrogen use. Biogas, produced by anaerobic digestion of wastewater, organic waste, agricultural waste, industrial waste, and animal by-products is a potential source of renewable energy. In this work, we have discussed Hydrogen production and End-Uses from CHHP system for the campus using local resources. Following the resource assessment study, the team selects FuelCell Energy DFC1500™ unit as a molten carbonate fuel cell to study of combined heat, hydrogen and power (CHHP) system based on a molten carbonate fuel cell fed by biogas produced by anaerobic digestion. The CHHP system provides approximately 650 kg/day. The total hydrogen usage 123 kg/day on the university campus including personal transportation applications, backup power applications, portable power applications, and other mobility applications are 56, 16, 29, 17, and 5 respectively. The excess hydrogen could be sold to a gas retailer. In conclusion, the CHHP system will be able to reduce fossil fuel usage, greenhouse gas emissions and hydrogen generated is used to power different applications on the university campus.     

Block spatial scheduling modelling and application in shipbuilding

With the wide application of module-shipbuilding technology, problems related to block spatial scheduling occur in various working areas, and this restricts the productivity of shipbuilding. To address the problems and to obtain the optimum block sequence and spatial layout, typical block features and work plates were investigated. A heuristic spatial scheduling model was established based on the investigation and proposed strategies with the objective to minimise makespan. With the heuristic algorithm, a block spatial scheduling system was developed and implemented with real data from a large ship. Through the spatial scheduling system, visual results of daily block layouts and progress charts for all blocks can be easily obtained and work orders can also be created for site workers. Several other spatial scheduling methods are described and compared with the above-mentioned heuristic algorithm. The result shows that the heuristic algorithm is better than Cplex and a genetic algorithm in solving large-scale block scheduling, and the heuristic algorithm is better than a grid algorithm and manual scheduling in all aspects such as makespan, utilisation of work plates, runtime of scheduling and on-time delivery. The developed block spatial scheduling system is applied in a block production shop of a modern shipyard and shows good performance.