一体式沼气安全脱硫反应器的操作优化和运行性能

文章采用正交试验考察了曝气量、气液比、脱硫液碱度对一体式沼气安全脱硫反应器脱硫效能的影响.试验结果表明,操作条件对反应器脱硫效能的影响程度为:曝气量＞脱硫液碱度＞气液比.在反应器容积气体负荷为32.5 m3·m-3d-1,硫化氢浓度为10 g · m-3的条件下,最佳操作条件组合为曝气量72 m3·m-3d-1,脱硫液碱度为4000 mg·L-1,气液比为0.625.在反应器容积气体负荷为40 m3·m-3d-1,硫化氢浓度高达20 g·m-3的条件下,反应器的容积硫化物去除率为0.74 kg·m-3d-1,沼气脱硫率为93.8％.一体式沼气安全脱硫反应器脱硫成本为0.11元·m-3和6元·(kg-S)-1.     

沼气生物脱硫工艺的小试研究

对采用填料塔吸收和生物氧化工艺去除沼气中H2S进行小试研究,生物氧化采用生物膜工艺。研究了pH,气液体积比,吸收液温度和溶解氧浓度等因素对去除H2S的影响。沼气中H2S含量在3000~4000 mg.m-3,吸收液pH为7.8左右,气液体积比10∶1,吸收液温度25℃条件下,处理后H2S浓度低于200 mg.m-3,H2S去除率大于90%。H2S生物氧化主要产物为单质硫和SO42-,控制DO在1.0 mg.L-1左右,生成硫酸根比例小于5%。     

宁波大型餐厨垃圾厌氧发酵装置简介

针对餐厨垃圾处理过程中产生大量高浓度有机废水的现状,将该废水进行厌氧发酵,去除有机物同时回收生物质能(沼气)并加以应用.文章以宁波市某沼气工程为例介绍了餐厨垃圾废水通过厌氧发酵生产沼气的工艺技术.该工程废水pH 3.5～4.0,CODcr80～120 g·L-1,处理量为110 t·d-1,控制厌氧发酵温度为(35±3)℃,每去除1 kgCODcr,可产沼气0.6～0.7m3,产气率为3.0～4.0 m3·m-3d-1,CODcr去除率达到91%以上,年可产沼气260万m3,可发电450万kWh.     

户用沼气池建设对改善农村室内环境效果分析

文章通过定点采样,fi等方法,定量对比分析户用沼气池对农村室内环境改善效果。研究结果表明:沼气户室内空气中CO,NH_3,SO_2,PM_(10)等污染物浓度分别为5.64 mg·m~(-3),1.05 mg·m~(-3),0.38 mg·m~(-3),0.57mg·m~(-3),而非沼气户室内4种污染物浓度分别为144.76 mg·m~(-3),4.38 mg·m~(-3),0.73 mg·m~(-3),0.87 mg·m~(-3),沼气户明显低于非沼气户,且4种污染物浓度随季节而变化。另外,沼气户相对于非沼气户室内空气中四项污染物浓度贡献率分别为96.10%,76.03%,47.9%,34.48%。可见,户用沼气池建设对改善农村室内环境效果显著。     

UASB处理柠檬酸废水及其沼气的利用

利用UASB处理高浓度柠檬酸有机废水 ,COD的去除效率达到 90 %以上 ,去除COD的沼气产率为 0 .6m3 ·kgCOD-1,沼气中甲烷含量为 70 % (体积 ) ,沼气的热值为 2 5 .6MJ·m-3 ,沼气经脱硫后用于居民燃气、沼气锅炉和直燃机燃烧。     

沼气循环厌氧颗粒污泥床反应器的运行特性

以厌氧絮状污泥接种,投加少量颗粒活性炭(GAC),处理高浓度自配水的上流式厌氧生物反应器在无沼气循环下,经18天运行即实现了污泥颗粒化,按反应区容积计算的有机负荷(OLR)达到15 kgCOD·m-3d-1,COD去除率为87%;启动沼气循环,在气体上升流速约2.1 m·h-1的条件下,几乎所有颗粒污泥在2天内发生解体;但继续沼气循环,经过在OLR约为36 kgCOD·m-3d-1下连续运行49天反应器内又重新形成了颗粒污泥;随后,反应器的OLR迅速提高到并保持在90kgCOD·m-3d-1左右,稳定运行18天,COD去除率在95%以上;沼气循环可强化反应器内的混合程度,使其离散系数D达到0.368.     

基于生命周期分析的禽畜养殖厂沼气工程性能评价

为对比研究大型沼气工程不同沼液处理方式造成的综合性能差异,文章以某禽畜养殖厂沼气工程为例,以生命周期评价法为基础,对发酵出料直接排放及固液分离后排放两种情况进行对比,在此基础上从经济、能效和环境影响3个方面进行评价。设定情况一为发酵出料排放灌溉;情况二为固液分离后沼渣作为有机肥基质出售。结果表明,经济性方面,当沼渣售价为300元·m-3时,情况二下动态投资回收期9. 8年、自筹资金动态投资回收期3. 21年,明显优于情况一的无法在运行周期20年内收回成本、自筹资金投资回收期9. 7年;当沼渣售价低于90元·m-3时,情况一有更好的经济性。能效评价中可得情况一、情况二能量产出比分别为7. 75,17. 26,情况二较情况一单位能耗升高26. 2%,单位产能增加2. 8倍。环境影响分析结果表示环境一、情况二的综合环境影响潜力为0. 072,0. 067。综合考虑经济、能效及环境影响三方面因素,情况二是经济、节能、相对环境友好的沼气工程运行模式。     

化学促进剂对寒区猪粪沼气发酵的影响及其工程示范

为研究寒区猪粪厌氧发酵产沼气时化学促进剂对反应体系发酵产气的影响,文章进行了化学促进剂的筛选试验以及最佳组合的配比试验,最后进行现场工程投加示范。实验结果显示,除Mo外,添加微量元素和生长因子都改善了产气量,其中,以酵母粉与Fe,Co,Ni的组合最佳;在最佳组合的四因素中,对累计产气量影响程度依次为:酵母粉﹥Co﹥Fe﹥Ni;最优组合为Fe Cl2·4H2O∶Co Cl2·6H2O∶Ni Cl2·6H2O∶酵母粉=3∶1∶1∶1;工程现场投加0.01%化学促进剂后,在10天的沼气发酵观察中,容积产气率基本都维持在0.3 m3·m-3d-1以上,最高达0.37m3·m-3d-1。通过以上结果可知,添加化学促进剂(以酵母粉与Fe,Co,Ni的组合最佳),可以提高低温环境下厌氧发酵的沼气产量和产率,并具有经济可行性和实际效益。     

EGSB厌氧系统处理瓜尔豆胶生产废水的研究

用EGSB厌氧反应器处理了食品工业中用量最大的添加剂之一——瓜尔豆胶的生产废水。结果显示:本研究所用的EGSB厌氧系统处理瓜尔豆胶生产废水,在容积COD负荷达18kgCOD.m-3d-1(进水COD浓度为30000mg.L-1)时,去除率可稳定在80%以上;出水的pH稳定在7.5左右;容积产气率随容积负荷的提高而逐渐升高,COD负荷达到18kg.m-3d-1时,平均沼气产量为22L.0.5d-1,每公斤COD平均可产生0.54m3沼气;沼气中的甲烷含量最高可达到82%。     

秸秆启动的沼气发酵研究

本文报告了一九八三年用碳酸氢铵(NH_4HCO_3)为添加剂,秸秆启动的沼气发酵试验研究结果:在实验室和六口1m~3水压式沼气池小试基础上,采用两口8m~3水压式沼气池进行生产应用性试验所获得的数据,以及在生产上初步试行的效果。秸秆启动,始发酵期30天,总产沼气66.978m~3,平均日产沼气2.223m~3,产气率0.327m~3/m~3料液·天,0.279m~3/m~3池·天,0.167m~3/kg·TS,0.234m~3/kg·VS.运转150天,总产沼气250.967m~3,平均日产沼气1.673m~3,产气率0.246m~3/m~3料液·天,0.209m~3/m~3池·天,0.312m~3/kg·TS,0.428m~3/kg·VS。沼气中CH_4含量为54.9％。     

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。     

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.