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14781.多避难所研究,以评估生长,季节和休眠,季烧伤的有效性来控制香蒲
[电力、热力、燃气及水生产和供应业] [2014-08-06]
Proliferation of invasive cattails (for example, Typha x glauca, T. angustifolia) is a concern of wetland managers across the country, and numerous methods have been used to control the spatial extent and density of the plant. To date, however, no single method has proven widely or consistently effective at reducing the long-term growth and spread of these species. We performed a multi-refuge study to evaluate the relative effects of growing-season and dormant-season prescribed burns on cattail production and to gain insight on variables such as soil moisture, groundwater, and biomass that affect the efficacy of burning as a control method. Results indicate total cattail cover recovers to pre-burn levels within 1 year regardless of whether the controlled burn was implemented during the growing season or dormant season. Growing-season burns, however, did result in lower aboveground and belowground cattail biomass 1-year post-burn, whereas no significant change in biomass was detected for dormant-season burns. Study results support the premise that burns implemented during the growing season should have a greater effect on nutrient reserves and cattail re-growth.
关键词:香蒲;植物生长;湿地;生物质能;作物;烧伤;地下水
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14782.技术简介:离网农村电气化中的太阳能利用
[电力、热力、燃气及水生产和供应业] [2014-08-06]
Photovoltaics is the most popular technology choice for off-grid rural electrification. In the Philippines, some major socio-economic programs of the government utilize photovoltaics to bring electric power and economic development in remote rural areas. The main advantage of PV over other renewable energy technologies is its virtually inexhaustible source of power, i.e., the sun. PV converts solar radiation directly into electricity. The geographical location of the Philippines enables it to harness solar energy because of high daily insolation, ranging from 3.5 to 5.2 kWh per square meter, and the low seasonal variation of solar radiation. The solar potential is greatest during the summer months of May to July when the sun is positioned over the Northern Hemisphere. Conversely, the months with the weakest sunlight are November to January.
关键词:农村,太阳能;电力;光伏电站;可再生能源;太阳辐射
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14783.生物基单体以生物质基糠醛为聚酯和它们的量碳指标评价合成
[电力、热力、燃气及水生产和供应业] [2014-08-06]
Commercially available furfural has been produced from hemicellulose derived from inedible-biomass-based resources, and furfural has been converted into commercially available furan by decarboxylation. These heterocyclic compounds are important chemicals for the production of biomass-based monomers. Oxidation of furfural gave a mixture of maleic acid and FA. These were hydrogenated to give succinic acid. Dimethyl succinate was synthesized from FA by esterification and hydrogenation. These chemicals are useful as biomass-based monomers for biomass-based plastics. Fully biomass-based poly(butylene succinate) (PBS) was obtained by polycondensation of biomass-based 1,4-butanediol and biomass-based succinic acid or dimethyl succinate. Succinic anhydride (SAn) and tetrahydrofuran (THF) were also synthesized from furfural. Fully biomass-based poly(butylene oxide-co-butylene succinate) was obtained by ring-opening polymerization of biomass-based SAn and THF. Partially biomass-based poly(butylene terephthalate) was obtained by polycondensation of biomass-based 1,4-butanediol and petroleum-based terephthalic acid. The biomass carbon ratio calculated from ~(14)C concentrations measured by accelerator mass spectroscopy verified that the PBS obtained in this study contained only biomass carbon. The polycondensation of biomass-based 1,4-butanediol and petroleum-based terephthalic acid or dimethyl terephthalate gave partially biomass-based poly(butylene terephthalate), which is an engineering plastic.
关键词:糠醛;半纤维素;生物质能;琥珀酸;氢化
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14784.海军生物燃料计划署的起源和国防能源的波动性问题
[电力、热力、燃气及水生产和供应业] [2014-08-06]
This thesis presents three catalysts for the origins of the Department of the Navy's biofuel initiative: (1) Section 526 of the Energy Independence and Security Act of 2007 effectively ended the Department of Defense s (DoD s) research program into synthetic fuels derived from fossil fuels; (2) the crude oil spot price reached a maximum daily price of $145.16 on July 14, 2008; and (3) the American Recovery and Reinvestment Act of 2009 appropriated over one billion dollars for biomass research and development. Although cost volatility has impacted the DoD s budget, the DoD already has used the Defense Working Capital Fund to make perceived oil prices less volatile to DoD users. Drop-in replaceable biofuels would not remove petroleum price volatility because biofuels act as close substitutes. The governments of other countries reduce cost volatility by managing fuel price risk using futures contracts; opinions differ on whether the DoD should pursue this option. To mitigate cost volatility, the Defense Business Board recommended exploring intragovernmental transfers between the DoD and Department of the Interior on two occasions. Long-term contracts could reduce volatility, but the DoD risks losing competitors in supply.
关键词:生物质能;防御系统;能源;原油
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14785.筛选常年暖季型草在干旱半亚热带环境的生物燃料原料的质量
[电力、热力、燃气及水生产和供应业] [2014-08-06]
A goal throughout much of the developed world is to replace a considerable portion of petroleum fuel with biofuels, including those from cellulosic biomass sources (U.S. Department of Energy, 2006). Plant species that are more water-use efficient are preferred, and biofuel crops will be needed for each specific environment. Cellulosic biomass crops have been identified for most agro-ecoregions as defined by temperature, rainfall, and soil types, but few have been identified for semiarid, subtropical regions, such as the Southern High Plains of the USA, which is dominated by short, mixed, and tallgrass prairie.
关键词:生物燃料;植物种类;纤维素生物燃料作物;作物
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14786.用于提高热回收的生物质锅炉
[电力、热力、燃气及水生产和供应业] [2014-08-06]
Combustion of biomass has been used by industry to produce steam and power for many years, but new technologies are being introduced to better recover the energy from biomass as well as to produce a synthetic gas (syngas) that can be used as a starting point in the production of automotive and diesel fuels as well as higher value chemicals. It is of significance that operating temperatures in combustion and gasification systems are often restricted by materials limitations resulting from the degradation of materials in the highest temperature areas. For systems recovering heat and/or generating steam, operating limits are often imposed by degradation of the superheater tubes that recover heat from the combustion gases at the highest temperatures. The steam temperature of biomass fueled boilers is limited by high temperature corrosion of superheater alloys in the ash deposit/flue gas environment. During visits with European researchers and boiler manufacturers and operators, it was learned that advanced European biomass boilers combine design modifications, process changes and corrosion resistant alloys to achieve substantially higher steam temperatures and efficiencies than U.S. biomass boilers. Design modifications to reduce superheater corrosion include adding an empty pass between the furnace and the superheater, installing cool tubes to trap low melting temperature chlorine deposits ahead of the superheater, heating the final superheater in the recirculated fluidizing medium of a circulating fluidized bed boiler, operating with a slagging superheater, designing superheaters for quick replacement, raising the superheater temperature above the dew point of the most corrosive deposits and installing an external superheater fired by a less-corrosive fuel. Process changes include diluting corrosive biomaterials with less-corrosive fuels, adding high sulfur fuels to convert alkali chlorides to lower melting temperature sulfates before they reach the superheater, washing chlorides out of agricultural residues and adding chemicals that convert alkali chlorides to aluminosilicates.
关键词:生物质能;锅炉;燃烧;耐腐蚀性;设计;流化床燃烧器
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14787.美国和俄罗斯白令海狭鳕陆架在2010年六月至八月的声拖网调查(DY1006)的结果
[电力、热力、燃气及水生产和供应业] [2014-08-06]
Eastern Bering Sea shelf walleye pollock (Theragra chalcogramma) abundance and distribution in midwater were assessed between 5 June and 7 August 2010 using acoustic-trawl techniques aboard the NOAA ship Oscar Dyson. The survey also assessed walleye pollock in the Cape Navarin area of Russia. Results showed that ocean surface temperatures were warmer in 2010 than in recent years (1.8DG 12.3DGC in 2010 vs. 0.7DG 8.3DGC in 2 0 and 0.9DG 8.9DGC in 2009). The majority of the pollock biomass in the U.S. Exclusive Economic Zone (EEZ) was located to the south and west of St. Matthew Island between the 100 m and 200 m isobaths. Estimated pollock abundance in midwater (between 16 m from the surface and 3 m off bottom) in the U.S. EEZ portion of the Bering Sea shelf was high compared to recent surveys. The 2010 pollock biomass estimate in the U.S. EEZ was 2.323 million metric tons (t). The 2009 biomass was 0.924 million t and the estimated 2008 biomass was 0.997 million t. East of 170DG W, the predominant length mode was 40 cm and most ages ranged between 3 and 6 years. In the U.S. west of 170DG W (87.4of total biomass), dominant modal lengths were 26, 16, and 39 cm, corresponding to pollock aged 2, 1, and 4, respectively. In Russia (5.3of total biomass), modal lengths and ages were generally similar to those in the U.S. west of 170DG W. Vertical distribution analyses indicated that 85of adult biomass was within 40 m of the seafloor. Juveniles were found both near the seafloor and higher in the water column; 65of juvenile biomass was within 40 m of the seafloor while 13was within 45 m of the surface. Finally, the first field tests of a non-extractive stereo camera-trawl system (Cam-Trawl) were successfully completed during the 2010 survey, and the multifrequency euphausiid backscatter index of abundance was successfully computed, indicating a reduced abundance of euphausiids compared with that in summer 2009.
关键词:狭鳕;海洋设备;生物质能;数据分析
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14788.浮游植物的粒子-一种新的赤潮建模方法
[电力、热力、燃气及水生产和供应业] [2014-08-06]
The authors investigate the hypothesis that phytoplankton blooms can be modeled by treating phytoplankton as discrete particles. A particle-tracking model is inserted into the CE-QUAL-ICM eutrophication model. Phytoplankton are quantified as carbonaceous biomass attached to the particles. Kinetics are adapted from CE-QUAL-ICM. The new model is operated along with existing hydrodynamic and watershed models of the Potomac River estuary. Initial application is to the winter-spring 1994 period. The new model is compared to observations and to a conventional model of the spring diatom bloom. The particle-based model successfully computes a subsurface chlorophyll maximum. The model characteristically displays heterogeneous spatial distribution of chlorophyll with high-amplitude oscillations at the semi-diurnal period. The characteristics and applicability of the particle approach are now established. The model requires optimization of parameter values to improve representation of the observed bloom in the Potomac.
关键词:时间序列分析;藻类;浮游植物;生物质能
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14789.使用ASPENPLUS模拟高温空气-蒸汽生物质气化的在吸式气化炉
[电力、热力、燃气及水生产和供应业] [2014-08-06]
A comprehensive process model is developed for high temperature air-steam biomass gasification in a downdraft gasifier using the ASPEN PLUS simulator.The simulation results are compared with the experimental data obtained through pilot scale downdraft gasifier.In this study,the model is used to investigate the effects of gasifying agent preheating,equivalence ratio (ER),and steam/biomass (S/B) on producer gas composition,high heating value (HHV),and cold gas efficiency (CGE).Results indicate that H2 and CO contents have increased when gasifying agent preheating is used,while gasifying agent preheating has no effect with H2 and CO at high ER.At high level of S/B,the concentrations of H2 and CO are related with water-gas shift reaction in significant.HHV and CGE depend on the concentrations of H2 and CO in producer gas,which can increase by preheated gasifying agent.However,gasifying agent preheating should apply with waste heat from the process because there is no additional cost of energy price.
关键词:下吸式气化炉; ASPEN PLUS;高温空气 - 蒸汽气化;生物质能
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14790.使用响应曲面法研究聚乙烯醇(PVA)-Collagen水凝胶的物理特性
[电力、热力、燃气及水生产和供应业] [2014-08-06]
A novel covalent bond cross-linked poly (vinyl alcohol) (PVA)-collagen hydrogel was prepared and the physical properties were studied.The carboxyl groups were introduced into PVA through the reaction with chloroacetic acid.The EDC and NHS were used as cross-linker.The hydrogels were prepared by repeated freezing and thawing.For a better understanding of the influence of the parameters and their interaction,three factors were investigated by a response surface methodology.The physical properties of the hydrogels were analyzed.The results indicated that the response surface models could significantly fit the response values.Moreover,comparing with the single factor,the interactions between factors had more obvious effects to the physical properties of PVA-Collagen hydrogels.After the analysis of factors' influences and investigation of the data and trends,the structure of the hydrogels might be the driving force of the different physical behaviors.
关键词:聚(乙烯醇);胶原蛋白;凝胶;物理性能;生物质能