高温空气气化生物质的平衡模型研究

在考虑气化过程中碳的部分转化及系统散热的基础上,对甲烷反应的平衡常数进行修正,建立了基于物料平衡、化学平衡及能量平衡的高温空气气化生物质的平衡模型,模型计算结果与文献试验数据相符。利用该修正模型研究了林木废弃物在下吸式固定床、高温空气气化条件下,空气预热温度、原料含水量及空气当量比对产气组成、气体热值和气化效率的影响。结果表明:提高空气预热温度有利于产气,而原料含水量应尽量降低;空气当量比为0.34时,气化效果最理想。     

小型生物质气化炉HEGF-2的设计及实验研究

针对目前小型生物质气化炉结构存在的缺陷,设计了一种小型生物质气化炉,并以其为研究对象,自行搭建了实验台,进行了实验研究。实验中,通过改变气化剂空气流量,分析了气化剂空气流量对气化炉性能的影响,并通过改变燃气配风量得到了配风量对气化炉烟气排放的影响。实验结果表明,HEGF-2型生物质气化炉具有结构简单、成本低、运行稳定、换热充分、产气品质和热值高、节能环保等优点。     

下吸式气化炉木屑高温蒸汽气化制取富H2实验

设计了生物质高温蒸汽气化实验平台,主反应器为高温蒸汽发生系统和带有喉口的下吸式气化炉。利用该实验平台对木屑进行高温蒸汽气化研究,气化过程通入的蒸汽温度控制在600~1 000℃。实验结果表明:高温蒸汽既是气化过程的气化剂又是部分热载体,能有效提高气化效率,并维持炉内温度场的稳定。实验条件下,气化气可燃组分体积分数达到77%以上,当蒸汽温度为(948±4)℃时,气化气中H2体积分数达到(51.83±0.12)%,气体热值为9.81 MJ/m3,H2/CO组分比达到2.17,气化气可持续稳定燃烧,气化性能较为理想。     

木块气化过程焦油联合脱除工况优化

基于松木块气化试验数据,建立了燃气焦油炉内、炉外联合脱除过程最小二乘支持向量机模型（LS—SVM）。在燃气焦油炉内脱除工况优化基础上,针对催化剂活性进一步拟合了燃气焦油炉外催化裂解脱除过程多目标优化模型,优化计算得到气化燃气焦油联合脱除工况的Pareto最优解集。寻优结果表明,气化炉出口燃气焦油质量浓度低于2g/m3,满足焦油催化裂解器对入口燃气焦油含量要求;焦油催化裂解器出口燃气焦油质量浓度降低至0.126~0.340g/m3之间,同时满足燃气热值大于4MJ/m3的工程要求,燃气总体品质明显优于试验结果。     

松木屑成型颗粒制备富氢产品气试验研究

基于生物质气化技术,采用下吸式气化炉为反应器,以高温水蒸气作为气化剂,选取温度和S/B(水蒸气流量与生物质气化量比)作为影响因素,炉体温度的变化范围700~950℃,S/B取值范围0.3~1.0,对产品气的组分变化规律进行分析,探讨了炉内的气化反应特性。试验结果表明,下吸式气化炉碳层内的水蒸气气化反应及焦油裂解反应对制取富氢燃气有重要作用,H2和CO的产率随温度的升高而增加,在温度增加到一定值后,H2体积分数达到峰值,继续升高温度导致H2的体积分数有所下降。S/B的增加有利于产品气中的H2含量的提升,但吸热反应造成炉内床体的反应温度下降,抑制H2体积分数的增加。在本试验条件下,H2的体积分数最大达到47.67%,对应的工况S/B为1.0,温度为900℃。     

下吸式固定床生物质气化温度场和组分场分布特性

首先采用多维数值模拟方法解析了下吸式固定床反应器生物质气化反应的发展过程,并通过主动配气下吸式固定床的气化试验结果验证了该数值解析方法的可行性。在此基础上,解析了气化过程中炉内温度场和组分场的分布特性。结果表明,空气当量比RER是影响下吸式固定床气化过程气化特性的重要因素,并且对于炉内温度场分布和气化产气组分场的最优取值范围为0.24～0.28。     

草浆黑液半焦直接苛化水蒸气气化特性研究

采用管式炉在750~900℃内进行了草浆黑液半焦水蒸气气化实验,考察了温度、苛化剂TiO2对气体产物及固体产物的影响;采用热重分析仪在850℃下进行了半焦的水蒸气气化实验,探究了TiO2对半焦热失重特性的影响。结果表明:在750~900℃内,TiO2的添加使得气体产物中CO2增加约5%、H2减少约5%,碳转化率上升约10%,产气热值下降约7%;TiO2可避免气化过程中熔融物的生成;随着温度的升高,固体产物中无机盐的种类未发生变化;TiO2与半焦中的Na2CO3反应生成Na2O·nTiO2,与Na2SiO3结合生成Na2TiSiO5,改变了元素Na与Si的存在形态。     

林木废弃物固定床气化试验研究

以生物质气化理论为依据,设计了一套小型下吸式气化系统,以大粒径的林木废弃物为原料进行气化试验研究。通过调节空气的流量,研究了当量比对产气组成、气体热值、气化效率、气体产量和木炭产量的影响。结果表明：大粒径的林木废弃物在气化炉内气化稳定,能产出优质的燃气及木炭;空气当量比存在一个最优值0．30。此时,气体组成如下：CO为21．6％,H2为11．3％,CH4为2．74％,C02为12．0％,02为1．44％,N2为51．0％,气体热值为4913kJ／m^3,气化效率为62．1％,产气量为112m^3／h,木炭产量为15．6kg。     

梯度链条式生物质气化炉数值模拟

梯度链条式生物质气化炉按照气化规律从空间上将生物质气化过程分为4个阶段,可实现对各气化阶段气化条件进行控制。为此,对梯度链条式生物质气化炉进行数值模拟,通过改变ER,计算出不同ER下床层顶部各组分的温度和浓度分布及炉膛气相的气化特性。模拟结果显示:气化合成气出口温度622.24℃;气化合成气中CO为13.81%、CH4为3.26%、C2H4为0.601%、C2H6为0.002%、CnHm为10.936%、H2为3.82%;碳转化效率为75.1%,低位热值为5 501k J/Nm3,气化效率为57.56%。该气化效果比下吸式固定床气化炉、固定床气化炉及鼓泡床气化炉空气气化效果好。     

生物质秸秆气化炉的设计与试验

根据相关指标设计上吸式生物质秸秆气化炉,并进行大量热解气化试验,试验结果表明:气化剂量对炉内温度、炉内温度对产气成分含量以及秸秆种类对产气的热值均有较大的影响,玉米秆热解可燃气热值13.13MJ/m3,桃仁壳热解可燃气热值16.18MJ/m3,烟秆(压缩颗粒)热解可燃气热值12.90MJ/m3,油菜秆热解可燃气热值14.62MJ/m3     

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.     

车用发动机润滑油失效规律与更换周期研究

研究在正常使用条件下１０Ｗ／３０－ＱＣ级润滑油用于某型车用发动机时所表现的失效规律,确认期服从两参数Ｗｅｉｂｕｌｌ分布,并给出分布的尺度参数η和形状参数ｍ之最佳线性无偏估计（ＢＬＵＥ）同时,还为定量分析,计算车用发动机润滑油的使用可靠性和合理确定其更换周期提供了一套可供借鉴的方法,并给出了具体的计算实例。     

农村剩余劳动力就业问题的探讨

论述了我国农村剩余劳动力就业的意义,并针对我国农村剩余劳动力的现状,提出多渠道促进农村剩余劳动力就业的途径和办法。     

乡（镇）农业技术推广体系存在的问题及对策

乡（镇）农技推广体系是农业发展的关键。介绍朝阳市农业技术推广体系的现状,针对目前体制及运行机制、服务手段等方面存在的问题,提出适合朝阳市乡（镇）农技推广体系改革与发展的对策,以期对全省农技推广体系改革和发展起到一些借鉴作用。     

草莓的采收与贮藏

草莓果味酸甜爽口,营养价值高,为人们所喜爱的应市鲜果之一。由于草莓易受损伤和微生物侵染,因此其采收、贮藏过程极为重要。介绍草莓采收过程中的注意事项以及11种贮藏保鲜技术的实施步骤和操作方法,推介9种加工方式,为草莓产业化提供技术支持。     

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。     

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。     

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。     

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.