京郊作物秸杆的利用现状

京郊作物秸杆的利用现状北京市农村能源办公室朱姝青一、秸杆的产量和资源价值１．农作物秸杆的产量：随着京郊农田生产力的提高而增加，其总量的多少，因种植结构的变化而变化，京郊作物秸杆总量１９８５年为２８３．２万吨，１９８９年为２３５．０７万吨，１９９４年为...     

京郊森林能源与环保建设在国民经济可持续发展战略中的作用

薪柴是人类最古老的能源，在我国有着悠久的经营利用历史。但长期以来，京郊农村能源和薪材资源严重缺乏，特别是边远山区群众生活艰难，森林过量采伐，造成严重的生态恶果，影响着京郊山区经济的发展。１京郊农村能源及新材消耗结构现状京郊农村能源分生产用能和生活用能两部分。主要能源有：煤、燃油、电力、秸秆、薪材和沼气等等。根据“八五”末对京郊农村能源需求调查结果，煤消耗量占第１位，占总耗能的３８．７％，第２位是秸秆，占２４．４％，第３位是薪材，占１８．９％，然后才是电、油、沼气及太阳能、地热等。京郊农村能源薪材…     

抚州市生态旅游资源的保护性开发

本文在介绍抚州市的生态旅游资源的基础上，分析了抚州市开发生态旅游的优势，提出了生态旅游资源开发中的保护与管理对策。     

京郊生物质能产业发展现状、存在问题与对策建议

近年来,在"三起来"工程等政府政策、资金、技术支持下,北京郊区生物质能产业发展已初具规模,改善了农村居民生活条件、能源消费结构和生态环境。但是,在生物质能产业的具体实践中,仍然存在一些问题制约其持续健康发展。文章对京郊生物质能产业发展现状,不同生物质能利用模式的共性问题、具体技术问题分别作了阐述,提出了促进京郊生物质能产业持续健康发展的对策建议。     

低碳技术在现代循环农业中的应用模式研究及案例分析

通过对低碳农业、现代循环农业的研究,提出了目前在低碳经济背景下的低碳技术及我国发展低碳循环农业的模式,即绿色有机模式、农业废弃物多级循环利用模式；以北京郊区某低碳循环农业示范园区为案例,分析了在传统模式下采用低碳技术及在CO2减排、节能、节水等方面的优势,明确了发展低碳农业的思路,提出了促进现代农业向低碳经济转型,实现农业的可持续发展的设想.     

"联丰"以技术创新拓展市场

浙江联丰集团公司以市场为导向，增强老产品科技含量，加快新产品开发步伐，２０００年１～４月产出的中央空调系列产品、压力容器等产品销量均超过了原先的主导产品──冷却塔，到２０００年４月底止，全公司实现销售收入 １４２５０万元，比去年同期增长 ２５％，利税 ２７５０万元，同比有较大幅度增长。 浙江联丰集团公司是以生产玻璃钢冷却塔为主导产品的国家级企业集团，是目前国内最大的冷却塔生产基地和技术开发中心。 为突出技术创新和技术进步，“联丰”专门成立了以技术发展部为龙头的省级技术开发中心，下设冷却塔、制冷机。压…     

"四位一体"三结合生产模式

“四位一体”三结合生产模式是在北方农村能源生态模式的基础上，在两栋北方农村能源生态模式之间搭建冷棚，种植以葡萄为主的果类作物而形成的一种生产模式。这种生产模式实现了种植与养殖相结合，有效利用物质循环，延长了生物链；实现了冷棚与暖棚相结合，充分利用土地资源，使劳动力得到合理分配；实现了果类生产与蔬菜类生产相结合，使价格得到互补，抵御了市场风险。１基本情况辽宁省喀左县羊角沟乡烧锅杖子村是有名的贫困村，全村５５５户，人口１７４６人，耕地总面积２３２hm２，为了摆脱贫困状况，通过省市县三级农村能源部门的帮…     

纸业基地循环经济发展模式

介绍某一纸业基地的循环经济发展模式。该纸业基地通过“七个集中”构建了因区的循环经济产业链，具体包括集中供热、集中供电、集中供冷、集中供水、集中治污、集中固废利用、集中物流。该纸业基地通过科学规划，将造纸和发电两大行业实现横向资源整合，提高能源利用率，减少污染物排放。     

自然保护区开展生态旅游及环境保护的探讨

在对自然保护区现存问题分析的基础上，提出在自然保护区开展生态旅游，并对其可行性进行分析，同时就如何在自然保护区内开展好生态旅游提出具体措施。     

农村能源"四位一体"模式应用及其效益

彭阳县自１９９８年实施国家生态农业建设项目之一的“四位一体”能源生态模式建造以来，共建成模式３３３座，其中已投产的３２１座。这种模式是依据生态学、经济学、系统工程学原理，以土地为基础，以太阳能为动力，以沼气为纽带，种植养殖相结合，通过生物能源转换技术，把沼气池、猪禽舍、厕所、太阳能温室融为一体的“两高一优”农业生产模式。应用该模式进行蔬菜生产，既可以保证蔬菜生长、猪禽育肥和沼气发酵所需的温度，又可为蔬菜生产提供优质的有机肥和氮肥，节约能源，降低成本。同时，还可以生产出无公害的优质蔬菜，提高蔬菜价…     

Natural-gas fueled spark-ignition (SI) and compression-ignition (CI) engine performance and emissions

Natural gas is a fossil fuel that has been used and investigated extensively for use in spark-ignition (SI) and compression-ignition (CI) engines. Compared with conventional gasoline engines, SI engines using natural gas can run at higher compression ratios, thus producing higher thermal efficiencies but also increased nitrogen oxide (NO_x) emissions, while producing lower emissions of carbon dioxide (CO₂), unburned hydrocarbons (HC) and carbon monoxide (CO). These engines also produce relatively less power than gasoline-fueled engines because of the convergence of one or more of three factors: a reduction in volumetric efficiency due to natural-gas injection in the intake manifold; the lower stoichiometric fuel/air ratio of natural gas compared to gasoline; and the lower equivalence ratio at which these engines may be run in order to reduce NO_x emissions. High NO_x emissions, especially at high loads, reduce with exhaust gas recirculation (EGR). However, EGR rates above a maximum value result in misfire and erratic engine operation. Hydrogen gas addition increases this EGR threshold significantly. In addition, hydrogen increases the flame speed of the natural gas-hydrogen mixture. Power levels can be increased with supercharging or turbocharging and intercooling. Natural gas is used to power CI engines via the dual-fuel mode, where a high-cetane fuel is injected along with the natural gas in order to provide a source of ignition for the charge. Thermal efficiency levels compared with normal diesel-fueled CI-engine operation are generally maintained with dual-fuel operation, and smoke levels are reduced significantly. At the same time, lower NO_x and CO₂ emissions, as well as higher HC and CO emissions compared with normal CI-engine operation at low and intermediate loads are recorded. These trends are caused by the low charge temperature and increased ignition delay, resulting in low combustion temperatures. Another factor is insufficient penetration and distribution of the pilot fuel in the charge, resulting in a lack of ignition centers. EGR admission at low and intermediate loads increases combustion temperatures, lowering unburned HC and CO emissions. Larger pilot fuel quantities at these load levels and hydrogen gas addition can also help increase combustion efficiency. Power output is lower at certain conditions than diesel-fueled engines, for reasons similar to those affecting power output of SI engines. In both cases the power output can be maintained with direct injection. Overall, natural gas can be used in both engine types; however further refinement and optimization of engines and fuel-injection systems is needed.     

Decomposition of limestone in a solar reactor

The thermal decomposition of limestone has been selected as a model reaction for developing and testing an atmospheric open solar reactor. The reactor consists of a cyclone gas/particle separator which has been modified to let the concentrated solar energy enter through a windowless aperture. The reacting particles are directly exposed to the solar irradiation. Experimentation with a 60 kW reactor prototype was conducted at PSI's 90m² parabolic solar concentrator, in a continuous mode of operation. A counter-current flow heat exchanger was employed to preheat the reactants. Eighty five percent degree of calcination was obtained for cement raw material and 15% of the solar input was converted into chemical energy (enthalpy).The technical feasibility of the solar thermal decomposition of limestone was experimentally demonstrated. The use of solar energy as a source for high-temperature process heat offers the potential of reducing significantly the CO₂ emissions from lime producing plants. Such a solar thermochemical process can find application in sunny rural areas for avoiding deforestation.     

Biohydrogen production by Anabaena sp. PCC 7120 wild-type and mutants under different conditions: Light, nickel, propane, carbon dioxide and nitrogen

Increasing awareness of environmental problems caused by the current use of fossil fuel-based energy, has led to the search for alternatives. Hydrogen is a good alternative and the cyanobacterium Anabaena sp. PCC 7120 is naturally able to produce molecular hydrogen, photosynthetically from water and light. However, this H₂ is rapidly consumed by the uptake hydrogenase.This study evaluated the hydrogen production of Anabaena sp. PCC 7120 wild-type and mutants: hupL⁻ (deficient in the uptake hydrogenase), hoxH⁻ (deficient in the bidirectional hydrogenase) and hupL⁻/hoxH⁻ (deficient in both hydrogenases) on several experimental conditions, such as gas atmosphere (argon and propane with or without N₂ and/or CO₂ addition), light intensity (54 and 152 ??Em⁻²s⁻¹), light regime (continuous and light/dark cycles 16 h/8 h) and nickel concentrations in the culture medium.In every assay, the hupL⁻ and hupL⁻/hoxH⁻ mutants stood out over wild-type cells and the hoxH⁻ mutant. Nevertheless, the hupL⁻ mutant showed the best hydrogen production except in an argon atmosphere under 16 h light/8 h dark cycles at 54 ??Em⁻²s⁻¹ in the light period, with 1 ??M of NiCl₂ supplementation in the culture medium, and under a propane atmosphere.In all strains, higher light intensity leads to higher hydrogen production and if there is a daily 1% of CO₂ addition in the gas atmosphere, hydrogen production could increase 5.8 times, related to the great increase in heterocysts differentiation (5 times more, approximately), whereas nickel supplementation in the culture medium was not shown to increase hydrogen production. The daily incorporation of 1% of CO₂ plus 1% of N₂ did not affect positively hydrogen production rate.     

Investigation of the thermodynamic and kinetic properties of La–Fe–B system hydrogen-storage alloys

La–Fe–B hydrogen-storage alloys were prepared using a vacuum induction-quenching furnace with a rotating copper wheel. The thermodynamic and kinetic properties of the La–Fe–B hydrogen-storage alloys were investigated in this work. The P–C–I curves of the La–Fe–B alloys were measured over a H₂ pressure range of 10⁻³ MPa to 2.0 MPa at temperatures of 313, 328, 343 and 353 K. The P–C–I curves revealed that the maximum hydrogen-storage capacity of the alloys exceeded 1.23 wt% at a pressure of approximately 1.0 MPa and temperature of 313 K. The standard enthalpy of formation ΔH and standard entropy of formation ΔS for the alloys' hydrides, obtained according to the van't Hoff equation, were consistent with their application as anode materials in alkaline media. The alloys also exhibited good absorption/desorption kinetics at room temperature.     

The Solar Office in context

The goal of sustainability in buildings can only hope to be realised if buildings are designed to both conserve and generate energy. The Solar Office at Doxford International is designed to minimise the use of energy while its external fabric is designed to replace such energy that is used. The recently completed building is now subject of a comprehensive monitoring programme. The programme covers both the performance of the 73 kW_p photovoltaic installation and the environmental conditions within the building as a whole. Hour by hour findings are posted on a dedicated web site. Photovoltaics could have the same impact on building form and layout as the invention of the passenger lift at the end of the last century.     

Hydrogen recovery from the photovoltaic electroflocculation-flotation process for harvesting Chlorella pyrenoidosa microalgae

In this paper, an integrated process using photovoltaic power to harvest microalgae by electro-flocculation (EF) and hydrogen recovery is presented. It is mainly favorable in regions with high solar radiation. The electro-flocculation efficiency (EFE) of Chlorella pyrenoidosa microalgae was investigated using various types of electrodes (aluminum, iron, zinc, copper and a non-sacrificial electrode of carbon). The best results regarding the EFE, and biomass contamination were achieved with aluminum and carbon electrodes where the electrical energy demand of the process for harvesting 1 kg of algae biomass was 0.28 and 0.34 kWh, respectively, while the energy yield of harvested hydrogen was 0.052 and 0.005 kWh kg^?1, respectively. The highest harvesting efficiency of 95.83 ± 0.87% was obtained with the aluminum electrode.The experimental hydrogen yields obtained were comparable with those calculated from theory. With a low net energy demand, microalgae EF may be a useful and low-cost technology.     

Electrochemical behavior of Mg–Li,Mg–Li–Al and Mg–Li–Al–Ce in sodium chloride solution

Mg–Li, Mg–Li–Al and Mg–Li–Al–Ce alloys were prepared and their electrochemical behavior in 0.7 M NaCl solutions was investigated by means of potentiodynamic polarization, potentiostatic current–time and electrochemical impedance spectroscopy measurements as well as by scanning electron microscopy examination. The effect of gallium oxide as an electrolyte additive on the potentiostatic discharge performance of these magnesium alloys was studied. The discharge activities and utilization efficiencies of these alloys increase in the order: Mg–Li < Mg–Li–Al < Mg–Li–Al–Ce, both in the absence and presence of Ga₂O₃. These alloys are more active than commercial magnesium alloy AZ31. The addition of Ga₂O₃ into NaCl electrolyte solution improved the discharging currents of the alloys by more than 4%, and enhanced the utilization efficiencies of the alloys by more than 6%. It also shortened the transition time for the discharge current to reach to a steady value. Electrochemical impedance spectroscopy measurements showed that the polarization resistance of the alloys decreases in the following order: Mg–Li > Mg–Li–Al > Mg–Li–Al–Ce. Mg–Li–Al–Ce exhibited the best performance in term of activity, utilization efficiency and activation time.     

Temperature dependence of the enthalpy of formation of metal hydrides characterized by an excess volume

A universal framework to calculate the temperature dependence of the excess enthalpy present in regions characterized by an excess volume is calculated for metals and metal hydrides. At high temperatures, the different contributions from the pressure–volume, heat capacity, entropy and work associated with the thermal expansion are studied separately and their magnitudes and signs are compared. It is found that the pressure–volume contribution opposes and dominates the other three contributions at both high temperature and excess volume, and it is thus found that this contribution becomes the leading temperature dependent contribution to the enthalpy of a material. The conditions under which a temperature change will reduce the enthalpy of formation of metal hydrides are also given and the Mg/MgH₂ system is studied as an example. Excluding the heat capacity contribution, an increase in temperature tends to offset the effect of the excess volume on the enthalpy of formation. It is also demonstrated that the impact of temperature will be more favorable to a reduction of the enthalpy of formation if a large fraction of the metal hydride is in a state of small excess volume compared to a small fraction of the hydride in a state of high excess volume.     

The effect of electrode infiltration on the performance of tubular solid oxide fuel cells under electrolysis and fuel cell modes

The electrochemical performance of two different anode supported tubular cells (50:50 wt% NiO:YSZ (yttria stabilized zirconia) or 34:66 vol.% Ni:YSZ) as the fuel electrode and YSZ as the electrolyte) under SOFC (solid oxide fuel cell) and SOEC (solid oxide electrolysis cell) modes were studied in this research. LSM (La_0.80Sr_0.20MnO_3−δ) was infiltrated into a thin porous YSZ layer to form the oxygen electrode of both cells and, in addition, SDC (Sm_0.2Ce_0.8O_1.9) was infiltrated into the fuel electrode of one of the cells. The microstructure of the infiltrated fuel cells showed a suitable distribution of fine LSM and SDC particles (50–100 nm) near the interface of electrodes and electrolyte and throughout the bulk of the electrodes. The results show that SDC infiltration not only enhances the electrochemical reaction in SOFC mode but improves the performance even more in SOEC mode. In addition, LSM infiltrated electrodes also boost the SOEC performance in comparison with standard LSM–YSZ composite electrodes, due to the well-dispersed LSM nanoparticles (favouring the electrochemical reactions) within the YSZ porous matrix.     

Tailored solar optics for maximal optical tolerance and concentration

Recently identified fundamental classes of dual-mirror double-tailored nonimaging optics have the potential to satisfy the pragmatic exigencies of concentrator photovoltaics. Via a comprehensive survey of their parameter space, including raytrace verification, we identify champion high-concentration high-efficiency designs that offer unprecedented optical tolerance (i.e., sensitivity to off-axis orientation) - a pivotal figure-of-merit with a basic bound that depends on concentration, exit angle, and effective solar angular radius. For comparison, results for the best corresponding dual-mirror aplanatic concentrators are also presented.