Hydrogen storage and distribution systems

Hydrogen storage and transportation or distribution is closely linked together. Hydrogen can be distributed continuously in pipelines or batch wise by ships, trucks, railway or airplanes. All batch transportation requires a storage system but also pipelines can be used as pressure storage system. Hydrogen exhibits the highest heating value per weight of all chemical fuels. Furthermore, hydrogen is regenerative and environment friendly. There are two reasons why hydrogen is not the major fuel of toady’s energy consumption: First of all, hydrogen is just an energy carrier. And, although it is the most abundant element in the universe, it has to be produced, since on earth it only occurs in the form of water. This implies that we have to pay for this energy, which results in a difficult economic task, because since the industrialization we are used to consuming energy for free. The second difficulty with hydrogen as an energy carrier is the low critical temperature of 33 K, i.e. hydrogen is a gas at room temperature. For mobile and in many cases also for stationary applications the volumetric and gravimetric density of hydrogen in a storage system is crucial. Hydrogen can be stored by six different methods and phenomena: high pressure gas cylinders (up to 800 bar), liquid hydrogen in cryogenic tanks (at 21 K), adsorbed hydrogen on materials with a large specific surface area (at T < 100 K), absorbed on interstitial sites in a host metal (at ambient pressure and temperature), chemically bond in covalent and ionic compounds (at ambient pressure), oxidation of reactive metals e.g. Li, Na, Mg, Al, Zn with water. These metals easily react with water to the corresponding hydroxide and liberate the hydrogen from the water. Finally, the metal hydroxides can be thermally reduced to the metals in a solar furnace.     

多级A/O工艺在国内的应用现状

多级A/O工艺目前在国内市政和部分工业污水处理领域应用较多,具有预处理和污泥处理系统简单,污泥负荷低、处理效果好且稳定,投资低,曝气系统效率高、运行成本较低,维护管理简便等特点,但是在实际运行中也发现存在一些问题,如土池结构不适合地下水位高的地区的局限性,沉淀池效果较差、稳定池多余占地且污泥淤积难以清除,关键设备国产质量有待提高,工业污水处理少数水质指标偏高,需要设计人员选择适合其条件的场合应用,并进一步总结、改进和完善.     

基于Maplnfo的项目排污可行性论证的研究与实践

Maplnfo是一种桌面GIS,功能非常强大。主要包括：地图输入、处理能力;关系型数据库功能;数据查询分析功能;多样化数据表达能力;功能齐全的系统开发工具;精美的地图输出功能;支持多种硬件操作平台;高精度的地图数据产品。该文重点运用Maplnfo的SQL查询功能,进行了建设项目排污可行性论证研究和实践,并实现了建设项目排污可行性论证的具体对象和可视化。     

2-Chlorophenol oxidation kinetic by photo-assisted Fenton process

Experimental data are presented to test and validate a kinetic model for the oxidation of 2-chlorophenol wastewater by photo-assisted Fenton process. The data showed that this process had produced good effects under acidic conductions. Up to 90% 2-chlorophenol was removed after 90-minute reaction time with H2O2 of 25% CODCr. in, while in UV/H2O2 system ordy 16.8% 2-chlorophenol was removed after one hour treatment. The optimal pH in this reaction occurred between pH 3.0 and pH 4.0. The reaction kinetics for photo-assisted Fenton process experimented in this research was investigated. Kinetic models were proposed for the treatment of 2-chlorophenol wastewater. The reaction was found to follow the 2nd order. The equations of reaction kinetics are as follows:-d[RH]/dt=KRH[RH][H2O2]0exp(-KH2o2t);-d[CODCr]/dt=KCODCr[CODCr][H2O2]0exp(-K′t).The prediction of the models was found to be in a good agreement with experimental results, thus confimfing the proposed reaction mechanism.     

重庆市近郊蔬菜基地土壤和蔬菜中重金属的质量现状

通过对重庆市近郊蔬菜基地土壤和蔬菜中重金属的监测和评价得出：重庆市近郊蔬菜基地部分土壤受到 Ｃｄ和Ｈｇ的污染；部分蔬菜受到Ｐｂ和Ｃｄ的污染。     

Environmental input-output model and its analysis with a focus on the solid waste management sectors

ＩｎｔｒｏｄｕｃｔｉｏｎＳｉｎｃｅｔｈｅｆｉｒｓｔｅｎｖｉｒｏｎｍｅｎｔａｌｉｎｐｕｔｏｕｔｐｕｔｍｏｄｅｌ(ＥＩＯＭ)(Ｃｕｍｂｅｒｌａｎｄ,1966)ｗａｓｅｓｔａｂｌｉｓｈｅｄｂｙｉｎｃｏｒｐｏｒａｔｉｎｇｅｎｖｉｒｏｎｍｅｎｔａｌｆａｃｔｏｒｓｉｎｔ?..     

从含酸废水中回收醋酸的方法

介绍各种从含酸废水中回收醋酸的工艺，对萃取法和吸附法回收醋酸工艺的主要工艺过程、应用范围和效果进行比较。     

环境因素对芦苇湿地CH4排放的影响

用封闭式箱法对辽河三角洲芦苇湿地温室气体CH4 排放进行了长期观测 .结果表明 ,CH4 排放有明显的季节变化规律 ,平均通量为 52 0 μg·m- 2 ·h- 1.土壤产CH4 活性主要发生在 0～ 5cm土层中 ,并随土层深度的增加而显著下降 .CH4 排放受环境因素影响很大 ,土壤氧化还原电位在 -1 1 0mV时就有CH4 排放 ,其排放量随氧化还原电位的下降而增加 .另外 ,随着淹水深度的增加 ,CH4 排放反而减少 .在测定期内 ,CH4 排放与温度呈明显的正相关 (R2 =0 1 96,n =2 1 ,P <0 .0 5) .     

炼铁高炉净环水高pH碱性运行的阻垢缓蚀研究

以某炼铁高炉妆环水为对象，对循环冷却水高ＰＨ碱性运行阻垢缓蚀进行了研究，筛选出了一复合配方。工业应用试验结果表明，此配方对Ａ３钢的污垢附着速率，腐蚀速率和污垢热阻均低于国家规定的指标要求，说明该配方具有良好的阻垢缓蚀性能。     

氧化塘离散数的研究

对模型氧化塘离散数d进行了相似分析,结果表明,模型塘的离散数d可以推广到原型中去.在试验资料基础上,提出了计算氧化塘离散数d值的经验公式,该公式反映了氧化塘内的极慢流动特征.应用该公式预测了有横向导流墙时氧化塘内的离散数,与试验结果符合较好.