生物质成型燃料及其发电技术

概括了生物质冷成型、热成型和常成型等成型技术的原理和种类.结合生物质成型燃料技术与生物质发电技术,阐述了生物质成型燃料直燃发电、混烧发电和气化发电等技术特点,指出了生物质成型燃料发电技术存在的问题和解决方案,展望了生物质成型燃料及其发电技术在中国的发展前景,总结了其在经济、环境和社会方面带来的效益,旨在为生物质资源的高效综合利用提供参考.     

生物质致密成型燃料制造技术研究现状

生物质能源转换方式有生物质气化、生物质固化和生物质液化3种方式,生物质固化后形成生物质致密成型燃料,其主要目的是将低密度的生物质转变为高密度的生物质燃料.为此,综述了生物质致密成型燃料制造技术在国内外的研究现状.同时,介绍了生物质致密成型工艺的研究现状,重点对当前国内外生物质致密成型燃料制造设备的研究和应用状况进行了总结和评述,最后讨论了我国生物质致密成型技术存在的薄弱环节及发展前景.     

生物质固体成型燃料成型工艺进展研究

介绍了生物质固体成型燃料技术和工艺的概念,回顾了国内外产业现状,提出生物质固体成型燃料的生产工艺分类方法,比较研究颗粒和压块成型工艺,分析了生物质固体成型设备和工艺配套设备现状,指出了生物质固体成型的设备与工艺存在的主要问题,并提出我国生物质成型工艺的发展方向,为生产中设备和工艺优化指以方向。     

生物质成型燃料品质影响因素及成型模型研究

生物质成型燃料是煤和天然气优秀的清洁替代能源,其技术的研究得到世界越来越多的关注和重视。在生物质成型过程中,生物质化学成分的含量与其成型质量有着密切关系,不同的生物质由于化学成分含量不同,决定了要采用不同的加工参数才能形成高品质的成型燃料。为此,首先介绍了生物质成型燃料的整个加工过程,并全面分析各主要的加工参数(原料含水量、颗粒粒径、温度和压力)对成型燃料品质的影响。同时,介绍了目前被广泛运用于生物质颗粒成型研究的3个成型模型,为进一步探究不同生物质的成型规律及成型条件,优化最佳加工参数提供理论依据。     

生物质燃料压缩成型技术的研究

介绍生物质燃料压缩成型原理和压缩成型工艺,论述了生物质燃料压缩成型技术的研究意义,综述了国内外研究现状,对常见的几种压缩工艺进行了探讨,最后总结了生物质燃料压缩成型技术的发展前景。     

生物质成型燃料加工方法与设备研究

生物质是一种取之不尽、用之不竭可再生的清洁能源。生物质成型燃料可以克服生物质热值低、容积密度小和物理形状不规则等缺点,成为生物质能源化利用的重要途径之一。为此,介绍了国内外生物质成型燃料的主要加工方法及其设备,对不同类型的制粒机和压块机的组成及其工作原理进行了全面的介绍,并对其工作条件和工作性能进行了对比分析,旨在为我国生物质成型设备的开发和研制提供参考,促进我国生物质成型燃料产业的进一步发展。     

生物质固体成型燃料层燃燃烧模型研究现状

介绍了生物质固体成型燃料层燃燃烧的数学模型,从挥发分析和燃烧模型、焦炭燃烧模型、辐射换热模型以及离散相模型几个方面阐述了国内外对生物质燃烧模型的研究。同时,分析了国内外生物质固体成型燃料燃烧数学模型研究存在的问题,并根据我国生物质固体成型燃料的特点,提出了我国固体生物质成型燃料燃烧模型今后的研究方向。     

生物质成型燃料加工技术分析研究

阐述了生物质成型燃料国内外发展现状、生物质成型燃料加工技术与装备的特点与使用对象;重点分析了现有的生物质成型燃料加工技术和装备在实际应用中的优缺点,得出目前我国的生物质固化成型装备在设备的实用性、系列化、规模化上还很不足,距国际先进水平还有不小的差距;这一问题以成型机最为突出,表现在生产率低、成型能耗高、主要工作部件寿命短、机器故障率多、费用高等方面;并依据生物质成型燃料发展趋势,提出目前我国生物质成型燃料加工设备的设计要点为：一是加工设备的原料适应性,二是加工设备的先进性与性价比。     

生物质固体成型燃料的关键技术及可行性

生物质固体成型燃料技术是生物质能开发利用的一项重要技术,具有广阔的发展前景。在介绍生物质成型燃料技术研究发展现状及比较分析国内外几种成型燃料生产技术的基础上,讨论并总结了生物质固体成型燃料的关键技术,分析了该项技术在我国推广应用的可行性。     

生物质压缩成型技术的研究与发展

我国有丰富的生物质资源,利用压缩成型技术对生物质进行压缩处理后,可以用作饲草料,也可以用作生物质能源。本文介绍生物质压缩成型机械的类型和特点,简述国内外生物质压缩成型技术的研究情况,剖析我国生物质压缩成型技术发展中存在的主要问题,提出发展对策及建议,为我国生物质压缩成型技术的研究与发展提供参考。     

Review of the Egyptian experience in implementing land drainage projects

About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.     

Agricultural drainage: Towards an integrated approach

Drainage needs to reclaim its rightful position as an indispensable element in the integrated management of land and water. An integrated approach to drainage can be developed by means of systematic mapping of the functions of natural resources systems (goods and services) and the values attributed to these functions by people. This mapping allows the exploration of the implications of particular drainage interventions. In that sense an analytical tool for understanding a drainage situation is proposed. The process dimension of the functions and values evaluation and assessment is participatory planning, modelled on co-management approaches to natural resources management. This provides a framework for discussion and negotiation of trade-offs related to the different functions and values related to drainage. In that sense the approach is a communication, planning and decision-making tool. The tool is called DRAINFRAME, which stands for Drainage Integrated Analytical Framework. The implementation of an integrated approach posits challenges for the governance, management and finance of drainage, as well as for research and design of drainage infrastructure and operation. Both have to be rethought from the perspective of multi-functionality. The paper concludes with five main policy messages.     

Overland water and salt flows in a set of rice paddies

Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m⁻¹) and an infiltration rate of 5.8 mm day⁻¹. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day⁻¹), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day⁻¹ was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.     

Maize ethanol feedstock production and net energy value as affected by climate variability and crop management practices

Ethanol from various plant resources, especially maize, is increasingly being used as a substitute for fossil fuels. The production potential of ethanol from maize varies with weather and climatic conditions and crop management practices. The merits and prospects of ethanol production have been evaluated based on its impact on greenhouse gas emissions, economic viability and national energy security. The net energy value (NEV), i.e. the output energy after all non-renewable energy inputs have been accounted for, is a measure of energy gain. At the same time, the NEV can be an indicator for the long-term sustainability of bio-ethanol production, regardless of other conditions e.g. climate change scenarios, global trade restrictions, or local variability in natural resources such as water availability. Crop management practices directly affect the NEV of ethanol. Moreover, both crop management practices and climate variability affect the NEV through the grain yield. The objective of this study was to assess the impact of crop management practices and climate variability on grain yield of maize for ethanol production and ethanol NEV for conditions that represent the southeastern USA. Maize grain yield was simulated with the dynamic crop growth model CSM–CERES–Maize and ethanol NEV was calculated using the simulated yield levels and crop management practices. The simulations were conducted for conditions representing Mitchell County, Georgia, USA, using weather data from 1939 to 2006 and local soil profile information. The impact of irrigation, nitrogen fertilizer, planting date and El Niño Southern Oscillation (ENSO) phases were determined for the maize cultivars DeKalb DKC 61-72 (RR2), Pioneer 31D58 and Pioneer 31G98. Crop management practices and ENSO phase had a significant impact on ethanol feedstock production and NEV. The NEV of ethanol produced from irrigated maize was more than two times higher and varied less than the NEV of ethanol from rainfed maize. NEV of ethanol produced from maize grown during La Niña years was significantly higher than maize grown during El Niño years, both under rainfed and irrigated conditions. This study showed the importance of crop management practices and climate variability on ethanol feedstock productivity and long-term energy sustainability as assessed by the NEV. We discuss methods of implementing the findings of this study in practical farming e.g. through market mechanisms and governmental initiatives.     

金谷子耐旱TG118引种试种及推广应用

对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。     

Quantifying the sustainability of agriculture

The rural sustainability index is a scientifically based tool to quantify the performance of agriculture. The sustainability of crop production is quantified from three perspectives; people, planet and profit. Within each perspective, one condition was selected that must be met to warrant agriculture. These are: No hazardous work should be used within the crop production chain; agricultural crops should not be grown on land allocated to nature by national law or regulations and, when a GM-crop is present or is introduced in a region, it should not harm development opportunities of other farmers. If these excluding conditions are met, the sustainability of agriculture is assessed through five performance indicators on school attendance, water use and consumption, fertilizer use, pesticide use, and farm income. For each of the five indicators, critical values and target values have been given that limit the transition range between non-sustainable and sustainable production. The five indicators are combined into a sustainability index. The index aims at improving the socio-economic position of farmers while protecting the environment.

热风,远红外和微波干燥香菇,蘑菇方程研究

通过一系列干燥试验，得到热风、远红外和微波对香菇的干燥方程，其形式分别为ＭＲ＝Ｂｅ￣（－ｒｔ），ＭＲ＝Ｂｅ￣（－ｒｔ）（单项扩散模型）和ＭＲ＝ｅ（Ｐａｇｅ方程）；并与干燥蘑菇（切片）的方程比较，结果是：热风、微波干燥时方程形式一样，远红外干燥时则不同。     

丹东地区玉米及水稻品种的优化选择

品种选择是农作物生产的第1步,不同品种在生育期、抗病性、抗倒性、区域适应性等方面存在较大的差异。选择适合本地区种植条件的优良品种与种子对农业生产和农民增收至关重要。结合丹东地区的实际情况,阐述在玉米、水稻品种的优化选择上应把握的原则和注意的问题,并提出相应的解决措施。     

河北石家庄市典型地区有机农业模式研究

在对河北石家庄辛集新绿科技发展有限公司和藁城大众肥业有限公司两个典型公司详细调查访谈的基础上,分析了有机鸡蛋和有机肥产品生产的相关模式,确定它们分别为公司+合作社+农户+基地和公司+基地的有机农业发展模式。研究认为河北存在企业主体力量的趋势不明显、营销网络体系不健全、销售渠道不畅、农户有机生产热情不高、认证方面混乱度高和缺乏有机生产合作社等问题,阻碍了有机农业的进一步发展,最后从经验吸取、技术创新、市场规范等方面提出了对策建议。     

农业纤维物料压缩流变研究现状

分析了国内外农业纤维物料压缩研究的现状,指出了存在问题;（１）多属“闭式”小模型压缩试验研究。（２）理论研究与实际脱节。（３）在压缩过程中的影响因素考虑的不够全面。（４）对压缩过程被压缩物料的流变特性研究不够;（５）同时要求给出被压缩物料施加恒应力（或恒应变）,并指出应加强以下几个方面的研究;（１）不同喂入量以不同压缩频率压缩时的蠕变和应力缓弛问题,（２）压缩室内草片和草捆在不同位置的蠕变和应力松