Improving photoreduction of CO2 with water to CH4 in a novel concentrated solar reactor

COphotoreduction is an attractive process which allows the storage of solar energy and synthesis of solar fuels. Many different photocatalytic systems have been developed, while the alternative photo-reactors are still insufficiently investigated. In this work, photoreduction of COwith HO into CHwas investigated in a modified concentrating solar reactor, using TiOand Pt/TiOas the catalysts. The TiOand Pt/TiOsamples were extensively characterized by different techniques including powder X-ray diffraction（XRD）, Nadsorption/desorption and UV–vis absorption. The catalytic performance of the TiOand Pt/TiOsamples in the gas phase was evaluated under unconcentrated and concentrated Xe-lamp light and nature solar light with different concentrating ratios. Various parameters of the reaction system and the catalysts were investigated and optimized to maximize the catalytic performance of COreduction system. Compared with the normal light irradiation, the TiOand Pt/TiOsamples show higher photocatalytic activity（about 6–7 times） for reducing COinto CHunder concentrated Xe-lamp light and nature solar light. In the range of experimental light intensity, it is found that the concentration of the light makes it suitable for the catalytic reaction, and increases the utilization efficiency of the TiOand Pt/TiOsamples while does not decrease the quantum efficiency.

A solar reactor for bio-diesel production from Pongamia oil: Studies on transesterfication process parameters and energy efficiency

Over exploitation of non-renewable energy reserves will lead to increase in price of petroleum fuels.Therefore there is a need for suitable and sustainable substitutes(renewable resource) for conventional fuels.In this study,an efficient and environmental friendly method for production of bio-diesel from Pongamia(Karanja) oil has been developed using a solar reactor.During the experimental study,the maximum temperature attained by the pongamia oil during the transesterification process was 64.1℃.The transesterification reaction was studied by varying different parameters such as reactant flow rate(5-20 L·h^(-1)),stirring speed(150-450 r·min^(-1)),catalyst mass loading(0.5%-2%) and methanol to oil ratio(3:1 to15:1).The maximum biodiesel yield was 83.11% at a flow rate of 5 L·h^(-1),stirring speed of 350 r·min^(-1),a methanol to oil ratio of 15:1,catalyst mass loading of 1% and reaction time of 270 min.The physical and chemical properties of biodiesel was analyzed as per American Society for Testing Materials(ASTM) standards and it had density of 938 kg·m^(-3),viscosity(28.7×10^(-6) m~2·s^(-1)),acid value(9.45 mg KOH·(g oil)^(-1))and flash point(215℃).The energy efficiency of solar heating process was determined by comparing the net energy ratio of direct heating process and solar heating process.For solar heating the net energy ratio(NER) was found to be 31.85 against 5.73 for direct heating.Similarly,net energy efficiency index was calculated for 10 kg production scale and was found to be increasing when scaled up which means that the solar heating process is more effective even in scaled up production.

Natural gas pyrolysis in double-walled reactor tubes using thermal plasma or concentrated solar radiation as external heating source

The thermal pyrolysis of natural gas as a clean hydrogen production route is examined. The concept of a double-walled reactor tube is proposed and implemented. Preliminary experiments using an external plasma heating source are carried out to validate this concept. The results point out the efficient CH4 dissociation above 1850 K （CH4 conversion over 90%） and the key influence of the gas residence time. Simulations are performed to predict the conversion rate of CH4 at the reactor outlet, and are consistent with experimental tendencies. A solar reactor prototype featuring four independent double-walled tubes is then developed. The heat in high temperature process required for the endothermic reaction of natural gas pyrolysis is supplied by concentrated solar energy. The tubes are heated uniformly by radiation using the blackbody effect of a cavity-receiver absorbing the concentrated solar irradiation through a quartz window. The gas composition at the reactor outlet, the chemical conversion of CH4, and the yield to H2 are determined with respect to reaction temperature, inlet gas flow-rates, and feed gas composition. The longer the gas residence time, the higher the CH4 conversion and H2 yield, whereas the lower the amount of acetylene. A CH4 conversion of 99% and H2 yield of about 85% are measured at 1880 K with 30% CH4 in the feed gas （6 L/min injected and residence time of 18 ms）, A temperature increase from 1870 K to 1970 K does not improve the H2 yield.

Numerical Study of Methane Dry Reforming Reaction in a Disk Reactor with Focused Solar Simulator

Heat transfer and thermochemical energy storage process of methane dry reforming in a disk reactor with focused solar simulator was modeled and analyzed. The results showed that thermochemical energy storage efficiency of disk reactor can reach 28.4%, and that is higher than that of tubular reactor.?The maximum reaction rate occurs at catalyst bed corner near the baffle, because the corner has high temperature and high reactant molar fraction. As reactant flow increases, methane conversion and thermochemical energy storage efficiency decrease as catalyst bed temperature and heat loss decrease.?The?thermochemical energy storage efficiency increased first and then decreased with methane molar ratio increasing, while?methane conversion?and the?thermochemical energy storage efficiency increased with reactant temperature increasing.?As catalyst bed porosity rises,?methane conversion?and?thermochemical energy storage efficiency increased first and then decreased, and optimum porosity is 0.31.

Solar System. Angular Momentum. Dark Matter Reactors

The developed Hypersphere World-Universe Model (WUM) is consistent with all Concepts of the World [1]. In WUM, we postulate the principal role of Angular Momentum and Dark Matter in Cosmological theories of the World. The most widely accepted model of Solar System formation, known as the Nebular hypothesis, does not solve the Angular Momentum problem—why is the orbital momentum of Jupiter larger than rotational momentum of the Sun? WUM is the only cosmological model in existence that is consistent with this Fundamental Law. The Nebular hypothesis does not solve Internal Heating and Diversity problems for all Planets and Moons in Solar system—why the actual mean surface temperature of them is higher than their effective temperature calculated based on the Sun’s heat for them and how could each one be so different if all of them came from the same nebula? The proposed concept of Dark Matter Reactors in Cores of all gravitationally-rounded Macroobjects successfully resolves these problems.

太阳能热化学转化技术研究进展

利用热化学反应将太阳能转化为易存储的化学产品,是实现太阳能大规模连续利用的有效方式。聚光器和反应器是太阳能热化学转化系统的核心设备。该文首先基于热化学反应进行温度的不同,对典型的低、中、高温太阳能热化学转化系统进行介绍,并对不同温度段系统中常用的聚光器类型进行总结,同时简要评述不同太阳能热化学转化系统的优缺点和发展趋势;然后基于太阳能热化学转化过程中传热方式的差异,对直接辐射加热型和间接辐射加热型太阳能反应器的种类、结构、工作原理和研究进展进行阐述。

生物质秸秆在聚光太阳能驱动下的动态热解特性实验

太阳能驱动生物质热解是重要的热化学互补技术,可将太阳能转化为高品质合成气中的化学能,并实现高效化学存储。为探究太阳能热解过程中的能量及化学转化特性,该文设计搭建了太阳能驱动生物质热解实验平台,并开展了太阳能驱动小麦秸秆热解实验研究。结果表明太阳能模拟器可提供平均能流密度为757 kW/m^(2)的高温焦斑,热解反应的最高温度和最大瞬时加热速率分别达到870℃和25℃/s。太阳能模拟器输入电功率由1.5 kW提升至6.0 kW,反应气体产物的质量百分比由24.7%上升至54.4%,对应的H_(2)动态浓度峰值(体积百分比)将由1.49%增加至11.48%,CO动态浓度峰值(体积百分比)由1.59%增加至11.61%,增大入射光能流密度有效促进了H_(2)、CO等燃料气体的生成,并能提高反应速率。研究结果将为太阳能驱动秸秆生物质的高效热解转化和太阳能反应器设计提供参考。

太阳能驱动甲烷干重整Ni泡沫反应器的设计与优化

太阳能驱动甲烷干重整转化技术可将CO_(2)和CH_(4)协同转化为燃料,是实现太阳能储存和CO_(2)减排的有效途径。多孔泡沫反应器因具有良好的热导率、较高的机械强度和气体渗透性,而成为太阳能驱动甲烷干重整转化技术规模化应用的研究热点。通过计算流体动力学模拟(CFD)研究了入口条件对反应器反应性能的影响。结果表明,入射总辐射量为130.8 W、入口流速为0.85 L/min时反应器反应性能最好,CH_(4)、CO_(2)转化率和光-燃料效率分别为79.73%、87.53%和37.03%。通过CFD耦合遗传算法(GA)对均匀多孔Ni泡沫反应器(简称“Ni泡沫反应器”)的孔结构与反应性能之间的关系进行了研究。结果表明,增大孔隙率可以在一定程度内提高Ni泡沫反应器的反应性能,而随着孔径的增大,反应性能先提高后降低,其中当孔隙率为0.93、孔径为1.72 mm时获得的Ni泡沫反应器(结构3)具有最优的反应性能,其CH_(4)、CO_(2)转化率和光-燃料效率分别为83.55%、89.53%和46.47%。之后提出两种双梯度渐变孔径Ni泡沫反应器的设计优化策略(分别为孔径轴向上由大变小、径向上由小变大渐变(结构1)和孔径轴向、径向上都由大到小渐变(结构2))。与结构3相比,结构1有助于辐射深入的同时保证中心区域温度更高,光-燃料效率为55.00%;结构2有助于太阳能的逐步吸收,进而提高温度均匀性,光-燃料效率为52.20%。

Life Origin in the Milky Way Galaxy: I. The Stellar Nucleogenesis of Elements Necessary for the Life Origin

Chemical elements in space can be synthesized by stellar nuclear reactors. Studying the dynamics of processes occurring in the stars introduces a concept of the ensemble-averaged stellar reactor. For future interstellar missions, the terrestrial and solar abundances were compared with considerable number of stars allocated in the ~200 pc solar neighborhood. According to the value of the effective temperature, four stellar classes are distinguished, for which the correlation coefficients and standard deviation are calculated. The statement about the possibility of transferring heavy elements synthesized by stars over long distances in space has been completely refuted. There is no immutability of the distribution of elements on neighboring stars and in the Solar System. It is shown that chemical elements are mainly synthesized inside each stellar reactor. The theory of the buoyancy of elements is generalized to stars. It has been suggested that stars overheat due to a shift in the parameters of nuclear processes occurring inside stars, which leads to the synthesis of heavy elements.

Solar System. Angular Momentum. New Physics

The most widely accepted model of Solar System formation, known as the Nebular hypothesis, does not solve the Angular Momentum problem—why is the orbital momentum of Jupiter larger than rotational momentum of the Sun? The present manuscript introduces a Rotational Fission model of creation and evolution of Macrostructures of the World (Superclusters, Galaxies, Extrasolar Systems), based on Overspinning Cores of the World’s Macroobjects, and the Law of Conservation of Angular Momentum. The Hypersphere World-Universe model is the only cosmological model in existence that is consistent with this Fundamental Law.

Solving the Solar Neutrino Problem

A new theoretical prediction that a plasma can produce antineutrinos is used to solve the solar neutrino problem. The difference between electron-positron induced fusion, and inertial fusion experiments that have been unsuccessful so far as commercial fusion reactors is also discussed.

Design of a multi-inlet solar thermochemical reactor for steam methane reforming with improved performance

Reactor structure design plays an important role in the performance of solar-thermal methane reforming reactors.Based on a conventional preheating reactor,this study proposed a cylindrical solar methane reforming reactor with multiple inlets to vary the temperature field distribution,which improved the temperature of the reaction region in the reactor,thereby improving the reactor performance.A multi-physical model that considers mass,momentum,species,energy conservation,as well as thermochemical reaction kinetics of methane reforming,was applied to numerically investigate the reactor performance and analyze the factors that affect performance improvement.It was found that compared with a conventional preheating reactor,the proposed cylindrical reac-tor with inner and external inlets for gas feeding enhanced heat recovery from the exhausted gas and provided a more suitable temperature field for the reaction in the reactor.Under different operating conditions,the methane conversion in the cylindrical reactor with multi-inlet increased by 9.5%to 19.1%,and the hydrogen production was enhanced by 12.1%to 40.3%in comparison with the conventional design,even though the total reaction catalyst volume was reduced.

几种新式太阳能光催化反应器的探讨

本文综述了几种新式的太阳能光催化反应器 ,对其结构和处理效果进行了比较 ,并对该法处理水的经济性进行简单的概述 ,指出光催化法是一种可以充分利用太阳能。

中低温太阳热能与甲醇重整互补制氢实验研究

本文提出一种利用150-300℃中低温太阳能驱动的甲醇-水重整反应制氢的新方法,该方法操作温度远低于其他太阳能热化学制氢方式。在5 kW抛物槽式太阳能集热器、吸收/反应器上对制氢关键过程进行了实验研究。实验结果表明:甲醇转化率可达90%以上,产物氢气浓度为66%-74%;1 mol甲醇制氢量可达2.90 mol,接近理想状态3 mol;基于能量品位的概念,深入分析了这一过程的能量转换机理;并对制氢成本进行了初步分析。本文的研究成果为高效利用中低温太阳热能与低能耗、低成本制氢提供一条新途径。

太阳能光催化反应器的研究进展与前景

通过对电光源反应器 ,使用太阳能的抛物槽反应器、平板型反应器、复合抛物面反应器性能的比较 ,提出复合抛物面反应器最具应用潜力。总结了光催化反应器研发中存在的问题 ,指出了实用型太阳能反应器向固定相、非聚光型反应器发展的趋势。剖析了太阳能光催化技术在饮用水深度处理中的应用前景。

不同作物秸秆生物反应堆对日光温室樱桃番茄生长、生育环境及其产量的影响

针对目前秸秆生物反应堆秸秆种类使用较为杂乱的问题,筛选适用于日光温室樱桃番茄种植的生物反应堆的秸秆作物种类,为日光温室樱桃番茄生产应用秸秆生物反应堆技术提供依据。试验选取常见的小麦、水稻、玉米、油葵4种作物秸秆,通过应用秸秆生物反应堆技术,测定秸秆生物反应堆对日光温室环境、樱桃番茄农艺性状、抗病性和产量等指标的影响,以常规栽培为对照,对其效果进行综合评价。结果表明,与对照相比,4个不同秸秆处理的生物反应堆均能提高温室土壤温度和CO2体积分数,促进樱桃番茄生长,提高产量,降低晚疫病的发病率。其中小麦秸秆反应堆处理下土壤温度分别较对照提高3.2℃,温室内湿度较对照下降21.1%,番茄晚疫病发病率较对照降低56.6%,番茄产量较对照增幅达19.5%。因此,在日光温室樱桃番茄栽培中,应用小麦秸秆生物反应堆技术的综合效应最好。

浅池型太阳能光催化反应动力学研究

研究了浅池型太阳能反应器中亚甲基蓝一级降解动力学常数与光辐射强度、反应器A/V值的关系 .当A/V与光照I均为变量时 ,提出了一个修正的动力学方程 :k =1 6 2 7× 10 -5I0 871(A/V) 1 3 57.同时 ,还建立了一个新的表观量子产率模型 :k =5 2 3CI0 871(A/V) 1 3 57.计算表观量子产率值为 0 17%— 0 30 % ,随着A/V、初始浓度的增大或光强的减小 。

内置秸秆反应堆和菌剂对日光温室土壤温度及越冬番茄生长的影响

以日光温室越冬番茄为试材,研究了内置秸秆反应堆和菌剂对日光温室土壤温度及越冬番茄生长的影响。结果表明:施用微生物菌剂、内置式秸秆反应堆技术及两者共用后平均分别增加土壤温度0.28、0.85、1.23℃;内置式秸秆反应堆技术及两者共用能够显著加快越冬番茄植株的生长速率,使番茄前期产量增加10.7%和11.8%。

太阳能光催化反应器的研究进展

为促进太阳能光催化反应器的研究和开发,从反应器中催化剂的存在形态、反应器的聚光形式以及应用3个方面对太阳能光催化反应器的研究现状进行了系统的综述,对催化剂悬浮型和固定膜型反应器以及聚光型和非聚光型反应器进行了比较,并分析了反应器在实际废水处理或者大批量处理中应用的可行性。