Hydrogen production from food wastes and gas post-treatment by CO2 adsorption

The production of H₂ by biological means, although still far from being a commercially viable proposition, offers great promise for the future. Purification of the biogas obtained may lead to the production of highly concentrated H₂ streams appropriate for industrial application. This research work evaluates the dark fermentation of food wastes and assesses the possibility of adsorbing CO₂ from the gas stream by means of a low cost biomass-based adsorbent. The reactor used was a completely stirred tank reactor run at different hydraulic retention times (HRTs) while the concentration of solids of the feeding stream was kept constant. The results obtained demonstrate that the H₂ yields from the fermentation of food wastes were affected by modifications in the hydraulic retention time (HRT) due to incomplete hydrolysis. The decrease in the duration of fermentation had a negative effect on the conversion of the substrate into soluble products. This resulted in a lower amount of soluble substrate being available for metabolisation by H₂ producing microflora leading to a reduction in specific H₂ production.Adsorption of CO₂ from a gas stream generated from the dark fermentation process was successfully carried out. The data obtained demonstrate that the column filled with biomass-derived activated carbon resulted in a high degree of hydrogen purification. Co-adsorption of H₂S onto the activated carbon also took place, there being no evidence of H₂S present in the bio-H₂ exiting the column. Nevertheless, the concentration of H₂S was very low, and this co-adsorption did not affect the CO₂ capture capacity of the activated carbon.     

氢气爆炸特性研究

本文研究、总结了氢气与空气(氢气与氧气)的混合物的爆炸特性.即氢气在空气中,在比较低燃烧界限的情况下,只有向上的传播和非常少的超压可以观测得到.正因为氢气的这种特性,将氢应用于科技将极大地推进社会进步,氢燃料将成为一种主要的能源.然而,氢技术应用的成功与否主要取决于氢使用的安全性.所以,必须掌握实际使用时氢气燃烧的性能.本文在日本过去十年实验数据的基础上,通过实验研究了氢气与空气混合物的燃点.研究了氢气、氧气混合物经氮气稀释后,按化学当量比例将不同浓度的氢气与空气进行混合,并得出了低温下的爆炸压力特性.随后,分别讨论了在初始压力下一致的情况下,试管直径相同的状况下,氢气与空气混合浓度相同的情况下,这三种爆轰传播限制之间的关系.得出了在空气中直接点燃的发生爆轰的最小试管直径,最小的装药量之间的关系,进行了爆轰危险性分级.最后,文章概括比较了氢与其他燃料的燃烧特性,评估了氢气燃烧过程中的危险与安全因素.     

STABLE HYDROGEN AND OXYGEN ISOTOPE COMPOSITION OF PRECIPITATION IN NORTHEASTERN COLORADO1

ABSTRACT: Where data are available, hydrologic studies may use precipitation's stable oxygen and hydrogen isotope composition to investigate streamflow, ground water/surface water interaction, and ground water recharge. Paleoclimate studies utilize the δ¹⁸O_{precipitation}‐T_air relationship, in conjunction with lake sediments, fossils, or old ground waters, for example, to estimate pale‐otemperatures. Ecological studies utilize precipitation and soil water isotope composition to track moisture uptake in plants, and to trace species migration patterns. Such studies require that the isotopic composition of precipitation be known. Oxygen‐18 (δ¹⁸O) and deuterium (δ²H) data for precipitation are lacking in the semi‐arid portion of the north‐central U.S. Great Plains, and thus there is a need to establish additional meteoric water lines as isotope input functions across the region, as well as to develop better understanding of the isotopic climate linkages that control oxygen and hydrogen isotope ratios in precipitation. This study determined the δ¹⁸O and δ²H composition of precipitation in the Pawnee Grasslands of northeastern Colorado from 1994 through 1998 using archived National Atmospheric Deposition Program samples. The resulting local water line follows the relationship δ²H = 7.86 δ¹⁸O‐7.66, and the data show a δ¹⁸O_weekly ‐ T_weekly relationship of δ¹⁸O = 0.560‐T (°C)‐18.8.     

废铁屑—H2O2法处理炼油厂含酚废水

用废铁屑作催化剂，Ｈ２Ｏ２作氧化剂，对炼厂汽提后含硫废水进行了除酚试验研究，考察了初始ＰＨ、Ｈ２Ｏ２投加量、废铁屑投加量对酚去除率的影响。对含酚量为３３１．５ｍｇ／Ｌ的废水，将其初始ＰＨ调至７．２，３０％Ｈ２Ｏ２的投加量为７．５ｍＬ／Ｌ，废铁屑的投加量为３－８ｇ／Ｌ，经２ｈ反应后，酚的脱除率可达９９．９％。     

玻璃纸生产废气中的CS_2和H_2S的治理

阐述了玻璃纸生产中CS2和H2S废气产生的原理,介绍了该废气处理的现状,总结了目前普遍采用的冷凝法、活性炭吸附法、活性碳纤维吸附法、改性活性炭吸附法、螯合铁氧化法、吸收—吸附法等处理方法的特点和效果。介绍了一种先采用螯合铁氧化法、再采用冷凝法、最后采用活性炭吸附法的综合处理工艺,可使废气达标排放。     

液化气球罐应力腐蚀开裂试验研究

由于炼制进口高硫原油,在炼油球罐检验中发现越来越多的内表面应力腐蚀裂纹。对球罐应力腐蚀开裂的原因和主要影响因素进行分析。从液化石油气球罐的安全性出发,采用线弹性断裂力学方法,针对16MnR和SPV50Q球罐所用钢材,在分析湿硫化氢环境下应力腐蚀开裂形式的基础上,通过改进的WOL预裂纹试样的应力腐蚀开裂试验,对不同球罐所用钢材、不同硫化氢浓度、不同焊接状态条件下的应力腐蚀开裂进行研究,并对设备所采用的材料、所处的介质浓度、材料的热处理状况等进行分析,并提出了防止对策。该方法也适用于液化石油气球罐应力腐蚀开裂,以预测事故的发生。     

生物絮凝吸附有机物降解动力学模型研究

生物絮凝吸附强化一级处理对于解决中小城镇污水处理问题有较大意义,在生物絮凝吸附后串联生物接触氧化法构成强化生物絮凝＋生物接触氧化一体化工艺,利用高负荷段的生物絮凝吸附强化一级处理提高SS、COD的去除率来降低后续生物膜的处理负荷,从而形成一种高效、低耗的新型处理工艺。探讨了生物絮凝吸附段的有机物降解动力学模型,并对模型进行了检验。     

碳氮源对光合细菌混合菌群产氢性能的影响

碳源和氮源是产氢光合细菌生长发育过程中不可缺少的营养物质,与光合细菌菌株产氢能力相关。以从花园土壤中富集分离出来的光合细菌混合菌群为研究对象,在血清瓶中于30℃下采用厌氧培养方式间歇培养8天,分别考察不同的碳源、氮源、碳氮源组合及其浓度变化对光合细菌产氢行为的影响。结果表明,碳氮源种类对光合细菌产氢能力有显著影响,与氮源相比,碳源对产氢量的影响更为显著,最佳碳源为葡萄糖,最佳氮源为草酸铵。最佳碳氮源组合为葡萄糖和谷氨酸钠组合,葡萄糖和谷氨酸钠浓度分别为3g/L和1g/L时,产氢量和最大产氢速率分别达41.35mLH2/(L-培养基)和0.328mLH2/(L-培养基·h)。研究结果为进一步探索产氢光合细菌生长的营养生理奠定了基础,对大规模培养条件的优化提供了依据。     

微生物电解产氢新技术研究现状与进展

微生物电解产氢是在微生物燃料电池的基础上发展而来的一种新的有潜力的产氢技术。将原有的微生物燃料电池进行适当改装,使其处于厌氧环境中,另外再加一个外加电压,从而使电池的阴极反应变成电子与质子的反应,产生氢气。微生物电解产氢技术的外加电压远低于电解水产氢技术所需的电压,产氢效率也比微生物发酵产氢高,且能将有机物彻底氧化,极大地提高了能源利用率。目前,国外已有研究将该技术应用于城市生活污水、养猪废水等,实现了废水的资源化利用。文章简述了微生物电解产氢的机理,归纳了其系统构成,并结合该技术在微生物、阳极、阴极和膜等方面的发展现状对其应用前景及发展方向进行了探讨。     

农业固体废弃物发酵产氢的研究

为了探索不同农业废弃物发酵产氢的能力,研究选取了10种农业生产中的主要固体废弃物:稻草、玉米秆、小麦秆、大麦秆、蚕豆秆、黄豆秆以及猪粪、牛粪、鸡粪、马粪作为原料,采用批量发酵工艺,进行厌氧发酵产氢的研究。结果表明,以乳酸调控发酵料液pH值在4.7～5.5之间,控制体系温度在(25±1)℃可以产生氢气。其中,各原料产氢能力顺序为:猪粪>大麦秆>玉米秆>稻草>蚕豆秆>鸡粪>牛粪>马粪>黄豆秆>小麦秆。