秸秆沼气生产关键技术——秸秆能源化技术系列(一)

<正>通过厌氧消化可以把秸秆转化成沼气。秸秆高效厌氧消化生产沼气需要解决3个关键技术问题:1秸秆预处理技术秸秆的木质纤维素含量较高,不易被厌氧菌消化,厌氧发酵产气量低,经济效益差,这是导致秸秆不能被大规模用于沼气生产的主要原因之一。一个简单有效的解决方法就是在厌氧发酵前,对秸秆进行物理、化学或生物预处理,把秸秆预先转化成易于消化的"食料",以显著提高秸秆的生物消化性能、产气率和经济性。常用的预处理方法有物理、化学与生物方     

亚硫酸氢盐预处理对黄贮玉米秸秆产甲烷潜力机理研究

为了更好地解决东北寒区农作物秸秆环境污染、资源浪费、转化利用率低的问题,开展了亚硫酸氢盐与黄贮法联用处理玉米秸秆对其产气潜力影响的研究。结果表明：当预处理液中亚硫酸氢钠浓度为6.0%时,预处理后的玉米秸秆酶解糖化率达83.0%左右,甲烷日产量达131.3 mL·g^-1TS,甲烷累积产气量达1462.2 mL·g^-1TS。相对于单一黄贮预处理法,采用联合法预处理后玉米秸秆组分中木质素被大量降解,纤维素保留率,结构疏散,纤维素、半纤维素可生化性提高,产气效果较好,有利于后续资源化的利用,且在一定范围内较低的亚硫酸氢钠用量好于较高的亚硫酸氢钠用量,所以亚硫酸氢钠用量在4.0%～5.0%为宜。适用于寒区秸秆资源化处理与利用的工程前预处理,且能节约成本,具有较好的经济效益、环境效益、社会效益。     

木醋液对玉米秸秆厌氧发酵的促进作用研究

试验观察了玉米秸秆青贮和用木醋液对玉米秸秆厌氧发酵产沼气的促进作用.结果表明,利用木醋液预处理青贮玉米秸秆,活性污泥接种率20％,厌氧发酵原料总固体(TS)10％,在35℃下厌氧发酵,可以使玉米秸秆产气高峰提前4～5天,木醋液预处理的青贮玉米秸秆提高产气量提高54％,达到425.7 mL·g-1,厌氧发酵过程中pH值稳定在6.6～7.1之间,产气过程平稳,所产沼气中甲烷含量平均提高10％,甲烷含量最高达到56％.     

基于3,5-二硝基水杨酸法的水稻秸秆酶解工艺

为了提高汽爆水稻秸秆还原糖的转化率,采用纤维素酶对水稻秸秆进行酶解实验.还原糖的含量用3,5-二硝基水杨酸法进行测定.实验选用加酶量、酶解时长和反应温度作为考察因素,以原始水稻秸秆与蒸汽爆破预处理水稻秸秆作对比.结果表明纤维素酶用量占秸秆干物质质量的10％,酶解时长48 h,反应温度50℃是一个较为理想的反应条件;原始水稻秸秆最大酶解还原糖产量约为9.7％;蒸汽爆破水稻秸秆最大酶解还原糖产量约为34.3％;蒸汽爆破预处理能够显著提高水稻秸秆的酶解还原糖产量,并缩短酶解反应时间.     

秸秆纤维素生物转化预处理方法研究进展

秸秆预处理效果直接影响其进一步的合理有效利用.分析了影响秸秆生物转化效率的主要因素,综述了秸秆处理的不同方法与特点,展望了秸秆预处理技术研究的发展趋势.     

蒸汽爆破预处理玉米秸秆厌氧发酵实验研究

2.0 Mpa压力下,保留时间60 s,90s和120 s对玉米秸秆汽爆预处理后进行厌氧发酵生产沼气实验,研究汽爆预处理秸秆厌氧发酵规律,探讨提高秸秆厌氧发酵产气量的新工艺.结果表明:蒸汽爆破预处理后的秸秆比未经预处理秸秆中温厌氧发酵的产气量296.8 mL·g-1提高16.8％～63.2％,保压时间为120 s时,秸秆厌氧发酵沼气产量达到最大值428.5 mL·g-1干物质.汽爆处理玉米秸秆厌氧发酵沼气中CH4含量在60％以上,发酵第20d累积产气量达到总产气量的80％,未发生结壳现象,主发酵周期比未汽爆秸秆大大缩短.     

NaOH与超声联合预处理玉米秸秆实验条件优化研究

试验选用超声与NaOH法对玉米秸秆进行联合预处理,通过分析预处理后秸秆还原糖含量、组分变化量、厌氧发酵产气量等参数,对预处理的条件进行优化.试验结果表明:3％ NaOH浓度,浸泡时间为48 h,超声功率为80 W,超声温度为50℃的预处理条件下,还原糖含量较高,为0.0947 g·g-1.联合试验组产气量比单一超声处理...     

菌种添加量对生物预处理小麦秸秆厌氧发酵的影响

对小麦秸秆进行了氨-生物联合预处理,在实验室自制的小型厌氧发酵装置上,对预处理后的小麦秸秆进行了厌氧发酵制取沼气试验,探讨了氨-生物联合预处理中,菌种的添加量对小麦秸秆厌氧发酵产沼气的影响.结果表明,在氨预处理尿素溶液质量浓度为35 g/L,生物预处理pH值为4,黄孢原毛平革菌和里氏木霉的添加比例为1∶1(数量级为109)的条件下,小麦秸秆厌氧发酵过程中沼气总产气量最大,为7 968 mL,较空白组提高了23.11％.发酵过程终了pH值、VFA和甲烷的变化均在正常的范围内,甲烷最高体积分数为51.33％,较空白组提高了6.01％,整个发酵过程历时23 d.     

微生物预处理秸秆对沼气产量的影响研究

近几年,国家每年的农作物秸秆总产量大约达到年均数亿吨以上,这些秸秆的利用率往往低于50%,大量秸秆在秋末被焚烧殆尽。不仅从一定层面上带来空气污染,也造成农作物原始资源的过度浪费。秸秆的微生物预处理问题一直是人们关注的话题。在这样的大环境下,利用白腐菌和一些复合菌对玉米秸秆进行预处理,既可以避免一定程度的浪费,还能大幅度提高秸秆的利用率。实验表明,秸秆经微生物预处理后,能明显提高沼气中的产气量和产气效率;利用混合菌对沼气进行预处理的效果最好,产气量最高,产气高峰期明显提前。采用哪种微生物也对产生的沼气有明显影响。实验表明:单纯利用白腐菌进行秸秆预处理同样会有良好的效果,反之,利用木霉进行秸秆预处理对厌氧发酵的促进作用效果则并不明显。这充分说明,利用木质素降解菌株进行秸秆预处理对提高秸秆的厌氧发酵效率具有重要的作用。     

预处理方式对水稻秸秆厌氧发酵产气特性的影响

在中温(35℃)条件下,分析了不同预处理方式对水稻秸秆厌氧发酵过程中产气特性的影响,比较了厌氧发酵前、后水稻秸秆组分变化的情况,结果表明:氨化预处理的秸秆产气量最大,VS(挥发性固体)产气量达到356.80 mL/g,比对照组高11.70％;各组甲烷质量分数的最大值均达到了70％以上,甲烷含量差异不显著;水稻秸秆厌氧发酵后的木质纤维素含量均呈现下降的趋势,木质纤维素的降解率与产气量成正比,氨化后的水稻秸秆与原水稻秸秆相比,纤维素、半纤维素和木质素的降解率分别为28.49％、51.73％和7.13％.     

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.     

瓦房店市水果生产标准化发展研究

瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。     

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。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

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.     

和谐社会理论建设的几点哲学思考

在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。     

A European irrigation map for spatially distributed agricultural modelling

We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications.     

粉质仪和拉伸仪在面粉生产中的应用

在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。     

农村信息化服务的现状及建设措施

分析当前我国农村信息化服务的现状,提出加强农村信息化服务的新举措。     

车辆ABS控制算法的研究及探讨

对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。