Experimental investigation of diesel engine using EGR and fuelled with Karanja oil methyl ester

Karanja oil methyl ester (KOME), a biodiesel prepared from Karanja oil, a potential source of non-edible oil in India and a prospective alternative to the diesel fuel, shows comparable performance and considerable reduction in emissions except NO_x. Exhaust gas recirculation (EGR) is a popular method of reducing the NO_x emission. The aim of this experimental work was to study the potential of the cooled EGR in a direct injection compression ignition engine operating with the KOME and its blend. The study was conducted with the different EGR rates. Performance and emission parameters were compared by using diesel, KOME and its blend employing EGR and with the same fuels without EGR. The study also differentiates the effect of EGR on KOME and its blend with the neat diesel. The effect of EGR was found to be slightly higher for KOME biodiesel and its blend than for neat diesel. Increased NO_x emission using KOME biodiesel was also found to be reduced by using EGR.     

垃圾填埋场渗滤液回灌法处理技术探讨

回灌法用于垃圾渗滤液的处理已逐渐成为研究的热点。通过对回灌法处理垃圾渗滤液的原理、特点及研究现状和进展的介绍。指出回灌法能有效地去除垃圾渗滤液中的有机物和重金属离子。但仍有待进一步完善和深入研究。     

RESPONSE OF PHYSICAL AND CHEMICAL PARAMETERS TO ELIMINATING THERMAL STRATIFICATION IN A RESERVOIR1

ABSTRACT The effects of maintaining a 19 ha Colorado montane reservoir in a thermally destratified condition for one year were evaluated. Water temperatures were kept nearly vertically agd horizontally isothermal throughout the year. The weighted mean temperature of the lake was 1-4°C colder in winter and 1-2°C warmer in summer than normal. Deep water in summer was up to 6°C warmer than typical hypolimnion temperatures, but summer surface temperature was unaltered. Without destratification dissolved oxygen depletion develops in summer and winter, but by eliminating stratification, oxygen was kept near saturation throughout the year. Alkalinity, pH, conductivity, and total residue were not significantly affected. Seston decreased which was probably due to declines in planktonic diatom populations. Increases in iron and manganese did not occur in deep water during destratification. Calcium concentrations increased slightly. Magnesium and most anions (chloride, nitrate-N, and silica) were not greatly altered, but sulfate concentration was reduced. Artificial destratification, as a reservoir management tool, will be very useful in altering chemical problems; particularly increasing oxygen and decreasing iron and manganese concentrations.     

好氧堆肥反应器设计及实验研究

设计了具有气液固三相收集功能的强制通风自动搅拌好氧堆肥反应器,并对其进行了好氧堆肥性能试验,通过监测温度、p H、含水率、COD、BOD_5、重金属(Cu)、种子发芽率、热值等指标来判定堆肥效果。实验结果表明,反应器使堆肥周期大大缩短,COD、BOD_5及生物毒性降低明显,45 d后堆体基本腐熟且稳定,堆体减量30%,堆肥效果良好。独有的"耙形"搅拌有利于减少物料温度、湿度和氧气浓度的差异,加快了反应进程。底部二级过滤系统有利于改善渗滤液质量,方便渗滤液的收集及回灌。该反应器可为小型禽畜粪便堆肥反应器的研发和推广提供参考。     

新型高效生物反应器类型和应用

近年来高效生物反应器得到不断发展,出现了多种新型生物反应器.从厌氧升流式生物反应器发展的经验和反应器的特点出发,提出了升流式反应器的结构、三相分离器的形式和污泥颗粒化现象等3个新概念是高效新型反应器的基础,进而在广义升流式污泥床反应器概念的基础上,提出具有传质效率高、处理能力强、有机负荷高以及抗冲击负荷能力强等优点的第三代高效生物反应器概念.     

渗滤液循环对填埋气体产生量影响的实验研究

以上海市生活垃圾组成为依据,通过填埋模拟柱实验研究了不同渗滤液循环方式对新鲜垃圾填埋层填埋气体(LFG)产生的影响.渗滤液循环方式包括:原液循环、厌氧预处理后循环、好氧预处理后循环、原液与陈垃圾柱出水混合后循环.结果表明,原液循环抑制了甲烷化进程,产气速率小,产气期分散.渗滤液经适当预处理后循环均能改善LFG的各项气量指标,表现为产气速率显著提高、产气期集中(本实验条件下约1a);Qt(实际累积产气量)增加,Q有效 Qt值(甲烷浓度大于50%的填埋气体量与实际累积产气量的比值)大于0 80,Qt Qp值(实际累积产气量与计算总产气量的比值)大于0 4.但渗滤液经不同预处理后循环对LFG各项气量指标的优化效果不同,排序为厌氧预处理后循环>原液与陈垃圾柱出水混合后循环>好氧预处理后循环.优化LFG各项气量指标的关键是:①缩短填埋层进入稳定的甲烷化阶段的时间;②减少垃圾中有机物的场外去除量.而渗滤液的预处理程度和方式对这两个因素有直接影响.     

厌氧发酵生物制氢微生物及工艺开发的研究进展

厌氧发酵生物制氢在国内外受到了普遍关注,如何确保稳定、持续、高效的产氢率成为生物制氢研究的关键问题所在.本文在查阅国内外大量文献的基础上,重点介绍了产氢发酵微生物、产氢菌种的构建、产氢反应器及厌氧发酵产氢工艺的最新研究状况.同时,就两相循环高温氢/甲烷发酵工艺的进一步发展前景提出了建议.     

厌氧型生物反应器产CH4期水解动力学模型研究

为研究渗滤液回灌和温度对填埋垃圾产CH4的影响,在不同温度下,通过对3个已进入产CH4期的厌氧型生物反应器实施不同的回灌操作,并根据p(CODCr)和产CH4速率的监测数据,建立了厌氧型生物反应器固相垃圾的水解模型.产CH4速率的模型计算的模拟值与D1,D2和D3柱实测值的相关系数分别为0.895 5,0.809 1和0.915 6,具有较高的可靠性.其中保持较高的产CH4速率且恒定温度的D2柱的固相垃圾水解系数是D1柱的12倍左右;同时随着回灌频率的降低,D3柱水解速率系数从0.007 6降到0.002 7,与D1柱的相对差也逐渐增大,保持较高的温度(35℃左右)和较高回灌频率有利于固相垃圾的水解和厌氧型生物反应器的快速稳定.     

酱油废水混凝处理的特征及机理研究

将酱油废水混凝沉淀过程中产生的物化污泥 ,回流至混凝反应的前段 ,加以重复利用 .试验表明 ,回流污泥与PAC、石灰混合后适用于高浓度的老抽酱油废水的混凝预处理 .污泥回用量为 5 0mL·L-1,PAC与石灰的投药量为 4 8mL·L-1,3 6g·L-1,比没有污泥回流时的 8 0mL·L-1,6 0g·L-1,减少了 4 0 % ,预处理过程中的沉淀污泥总产量下降 2 8 4 % .在此条件下 ,COD和色度平均去除率分别为 4 4 2 %和 93 2 % .结合透射电镜图片的机理分析表明 :石灰中的CaO可与废水中的糖类等物质反应生成沉淀 ,在回流污泥吸附卷扫与PAC电性中和的共同作用下 ,色度和COD得到明显去除 .     

渗滤液回灌量对其特性及填埋场稳定化的影响

采用4座规模为42m³的模拟实验柱,1号、2号和3号实验柱每周分别回灌填埋垃圾量5.3%,2.7%和0.67%的渗滤液,4号实验柱每周回灌填埋垃圾量0.33%的清水作为控制柱进行对比研究回灌量对渗滤液特性和填埋场稳定化进程的影响.结果表明,5.3%的渗滤液回灌比能更大程度地加速填埋场的稳定化进程,使有机物在更短的时间内释放,减小产甲烷的迟滞时间.采用2.7%回灌比的实验柱能形成更好的微生物环境,反应器温度保持在35℃,对渗滤液有最好的处理效果,COD和BOD₅的去除率分别达到了77%和88%,同时还具有最好的抗冲击负荷能力.在实际工程中,应该根据填埋场设计的目标来选择合适的渗滤液回灌量.