污泥厌氧发酵产沼气抑制物影响的研究进展

厌氧发酵产沼气作为污泥处置的重要技术,不仅能够解决生成量见长的污泥所造成的环境问题,而且能够缓解当前日益紧张的能源供需矛盾。氨、硫化物、金属离子、氢、短链及长链脂肪酸等物质可抑制厌氧发酵菌群的活性,从而显著降低污泥厌氧发酵产沼气效率。本文围绕影响污泥厌氧发酵产沼气过程的氨、硫化物、金属离子、氢、短链及长链脂肪酸等抑制物的研究进展进行了阐述及分析,以期为高效污泥厌氧发酵产沼气技术的研发提供参考。     

温度对污泥厌氧发酵产酸过程的影响

污泥厌氧发酵不仅可以产生短链脂肪酸补充污水脱氮除磷【l】工艺中碳源的不足,还可以实现污泥的减量化和资源化。该文综述了温度对污泥厌氧发酵产酸影响的研究进展,着重讨论了温度对污泥厌氧发酵过程中水解、短链脂肪酸（scFAs）累积、甲烷的产生和污泥减量化等方面的影响,并对今后的研究方向进行了展望。     

不同预处理方法促进初沉/剩余污泥厌氧发酵产沼气研究进展

系统地归纳了近年来促进污水厂初沉/剩余污泥厌氧发酵产沼气的主要处理方式,包括物理预处理方式（热预处理、超声波预处理、微波预处理、机械预处理）,化学预处理方式（臭氧预处理、碱预处理）以及生物预处理方式（酶预处理）等综合应用物理、化学和生物方法的预处理方式。并指出臭氧及碱的投加对于促进初沉/剩余污泥中有机物质水解的效果和促进产沼气量、微波的非热效应提高初沉/剩余污泥产沼气效能的影响以及多种预处理方式的联合应用是未来在促进初沉/剩余污泥产沼气领域值得研究的新方向。     

外源添加剂强化剩余污泥厌氧发酵产酸的影响研究

挥发性脂肪酸（VFA）是污水生物处理中反硝化脱氮和厌氧释磷过程必需的碳源,还能作为底物生产高附加值的产品,而利用剩余污泥进行厌氧发酵是产VFA的重要途径之一。为了提高污泥产酸效率,利用外源添加剂促进和强化污泥厌氧发酵产酸的研究逐渐引起重视。文章总结了抗生素、表面活性剂、植物化学物质和盐类四类外源添加剂对污泥厌氧发酵产酸过程的影响,分别从外源添加剂对污泥的增溶、水解、产酸和产甲烷四个过程进行了分析,同时阐述了外源添加剂在污泥中的降解、残留状况,最后提出对两种或两种以上的外源添加剂联用促进产酸和寻找能促进污泥产酸的共发酵基质也是今后的研究重点。     

污泥厌氧发酵产酸机理及应用研究进展

为了实现污水中污泥减量化和资源化,对其进行厌氧消化是目前国际上应用最广泛的处理方法。酸化阶段的重要产物——挥发性脂肪酸（VFAs）不仅可以作为污水脱氮除磷的碳源,还是合成生物质塑料聚羟基脂肪酸酯（PHAs）的理想底物。简单介绍了污泥厌氧发酵产酸的代谢机理和微生物机理,对近年来污泥厌氧发酵产酸的研究成果进行了梳理,重点论述了底物种类、预处理技术、pH值、发酵温度等因素对污泥厌氧发酵产酸的影响及研究进展,总结并对比了不同底物类型、发酵温度、酸性和碱性条件下都可影响发酵产酸的产量及酸种类分布,而污泥预处理技术则倾向于提高酸的产量,对酸种类分布影响不大。介绍了污泥厌氧发酵产酸在合成PHAs、生物能源和污水的脱氮除磷等方面的应用情况。最后,针对污泥厌氧发酵产酸会因底物有机成分不同,导致酸化效率有所差异,同时控制底物种类、pH值和温度等因素不仅影响产酸量,还会影响产酸类型和产物种类。提出了今后的研究方向主要是深入分析不同底物的酸化效率差异原因、污泥定向发酵产酸,实现总VFAs中各种酸比例调控。     

高浓度酒糟废水厌氧发酵产沼气条件研究

为验证利用酒糟厌氧发酵产沼气项目的可行性,并在小试的过程中收集相关数据,为今后的中试提供数据参考,在中温(30～40℃),pH为7.0～7.5条件下,采用一种自制的厌氧发酵装置对米酒酒糟厌氧发酵产沼气进行了小试。结果表明,米酒酒糟极易酸化形成大量挥发性脂肪酸(VFA),是产生沼气的原料。在进料COD为26000～68000 mg/L情况下,所产沼气中甲烷百分含量在34%～62%之间,沼气中甲烷含量随进料COD和COD去除率的升高而升高。酒糟发酵过程中需严格控制温度和pH。所产沼气中酸性阻燃气体含量很低,可用作工业燃料,利用高COD酒糟进行厌氧发酵产沼气可行。     

青岛海泊河污水处理厂沼气热电联产系统研究

对比了国内外污泥厌氧消化、沼气利用和生物质内燃机的研究和应用情况,我国污水处理厂污泥通过厌氧发酵热电联产仅占2%。介绍了海泊河污水处理厂污水和污泥的处理规模、处理工艺,分析了该厂沼气热电联产运行工艺和包括厌氧发酵系统、沼气热电联产系统及余热回收系统3部分的中温消化-热电联产流程的运行原理、运行参数和运行情况。2016年实际运行结果表明,热电联产运行稳定、收益较高,固定费用389.38万元/年,沼气发电收入593万元/年,净利润203.62万元/年。     

流速对垃圾渗滤液EGSB发酵产氢的影响

以生活垃圾堆肥厂初期渗滤液为对象,以厌氧颗粒污泥为接种物,研究了液体上升流速(Vup)对EGSB反应器厌氧发酵制氢系统的影响。分析了进、出水中CODCr、p H值、挥发性脂肪酸(VFAs)的变化及产气量和成分。结果表明在中温(35±1)℃,p H值为5.0~5.5,水力停留时间为24 h的条件下,液体上升速度的变化对系统的产氢能力有所影响,在Vup为3.7 m/h时,系统的CODCr去除率、氢气产生速率分别为49.6%~51.6%、1 996~2 183m L/(L·d),两者值均高于其它阶段,液相末端发酵产物中乙醇和乙酸总量占VFAs总量的80%以上,发酵类型以乙醇型发酵为主。     

厌氧发酵产氢污泥的驯化技术

以糖蜜废水为发酵底物,以污水处理厂剩余污泥为反应器启动污泥,污泥采用曝气氧化预处理方法,从而达到厌氧发酵产氢目的并提高其发酵产氢能力.试验表明,经曝气氧化预处理后的污泥可作为厌氧发酵生物制氢的接种污泥,且具有较高的产氢能力,在实验条件下,反应器稳定运行时产气量为3 L,发酵产气中氢气浓度为75.77%,液相末端发酵产物主要为乙醇、乙酸.     

污泥厌氧发酵产酸技术研究进展

阐述了污泥厌氧发酵产酸的机理;归纳了污泥厌氧发酵产酸的影响因素：C/N、温度、pH、污泥停留时间、污染物等,并指明控制污泥厌氧发酵体系C/N比为20～30,温度为25～40℃,pH为10,污泥停留时间为5～10 d以及合适的污染物浓度有利于SCFAs积累;综述了共发酵和联合预处理这两种污泥厌氧发酵产酸技术的最新研究进展,两种产酸技术均可显著提高SCFAs产量;最后提出了当前研究存在的不足,并对未来的研究方向做出了展望,旨在为污泥处理与处置、厌氧消化实现资源最大化提供参考。     

典型碳氢化合物水蒸气重整制氢研究进展

  烃水蒸气重整是目前获取氢能源的重要方法之一,而甲烷、汽油和柴油作为典型烃类原料可满足于不同规模氢能源的需求。本文重点从催化剂、反应工艺和反应机理及动力学三个方面对甲烷、汽油和柴油蒸汽重整制氢进行介绍和评述。指出甲烷重整制氢镍基催化剂的改性和反应器设计以及反应条件的优化是其必然的发展趋势,汽油和柴油重整制氢催化剂未来设计必须具备高抗硫性和抗积炭性。此外,需加强甲烷、汽油和柴油蒸气重整制氢的机理和动力学研究。     

A study of the hydrogen production from a small plasma converter

In this paper, the hydrogen production characteristics of a purpose-designed and built small scale plasma converter for small engines was investigated. Hydrogen was produced through the reformation of ionised hydrocarbon fuel and air mixture by means of a spark discharge.The experimental results showed that a suitable size of the reaction chamber can increase the concentration of the produced hydrogen and that under a given methane supply rate, a low O₂/C ratio resulted in high hydrogen production concentration as well as high hydrogen volume flow rate. As the methane supply rate was increased, however, the hydrogen concentration reduced while the hydrogen volume flow rate increased. Hydrogen concentration was also improved when the intake gas mixture resided longer in the reaction channel, although the hydrogen volume flow rate revealed an inversed trend. It was also shown that by combining an intake air swirl with an appropriate O₂/C ratio and methane supply rate, both the methane conversion efficiency and the hydrogen production concentration were improved. In general, under the optimal operating condition, the plasma converter produced a maximum hydrogen concentration of 48% and a hydrogen volume flow rate of 70 mL/min.     

甲烷化炉超温原因分析及对策

大型合成氨装置设置甲烷化炉的主要目的是把进入合成工序的氢氮气中的CO、CO2除去,以防造成合成塔催化剂中毒,导致催化剂活性下降无法满足合成工序生产要求。甲烷化炉运行状况直接关系到后续系统的安全稳定运行。     

Hydrogen production by decomposition of ethane-containing methane over carbon black catalysts

Mixtures of methane and small amounts of ethane were decomposed in the presence of carbon black (CB) catalysts at 1,073–1,223 K for hydrogen production. Although most of the added ethane was first decomposed to ethylene and hydrogen predominantly by non-catalytic reaction, subsequent decomposition of ethylene was effectively facilitated by the CB catalysts. Because some methane was produced from ethane, the net methane conversion decreased as the added ethane increased. The rate of hydrogen production from methane was decreased by the added ethane. A reason for this is that adsorption of methane on the active sites is inhibited by more easily adsorbing ethylene. In spite of this, the hydrogen yield increased with an increase of the added ethane because the contribution of ethane and ethylene decomposition to the hydrogen production was dominant over methane decomposition. A higher hydrogen yield was obtained in the presence of a higher-surface-area CB catalyst.     

Enhancement of Hydrogen Production by Fluidization in Industrial-Scale Steam Reformers

In this paper, the effect of the fluidization concept on the performance of methane steam reforming has been investigated by comparing a fluidized-bed steam reformer (FBSR) with an industrial-scale conventional steam reformer (CSR). Also, a fluidized-bed thermally coupled steam reformer (TCFBSR) and a fixed-bed thermally coupled steam reformer (TCSR) have been compared. In thermally coupled reactors, the hydrogenation of nitrobenzene to aniline exothermic reaction is employed. A steady state one dimensional heterogeneous model is applied to analyze methane conversion and hydrogen production for steam reforming of methane in different reactors (CSR, FBSR, TCSR, and TCFBSR). The modeling results show that, in FBSR, hydrogen production and methane conversion are increased by 2.13 and 0.52%, respectively, in comparison with CSR. Also, by using fluidized catalysts instead of fixed ones in TCSR, methane conversion and hydrogen yield are increased from 0.2776 to 0.2934 and from 0.9649 to 0.9836, respectively. These improvements represent the appropriate effect of the fluidization concept on the enhancement of hydrogen production in different steam reformers.     

Catalytic conversion of methane to more useful chemicals and fuels: a challenge for the 21st century

The very large reserves of methane, which often are found in remote regions, could serve as a feedstock for the production of chemicals and as a source of energy well into the 21st century. Although methane currently is being used in such important applications as the heating of homes and the generation of hydrogen for ammonia synthesis, its potential for the production of ethylene or liquid hydrocarbon fuels has not been fully realized. A number of strategies are being explored at levels that range from fundamental science to engineering technology. These include: (a) stream and carbon dioxide reforming or partial oxidation of methane to form carbon monoxide and hydrogen, followed by Fischer–Tropsch chemistry, (b) the direct oxidation of methane to methanol and formaldehyde, (c) oxidative coupling of methane to ethylene, and (d) direct conversion to aromatics and hydrogen in the absence of oxygen. Each alternative has its own set of limitations; however, economical separation is common to all with the most important issues being the separation of oxygen from air and the separation of hydrogen or hydrocarbons from dilute product streams. Extensive utilization of methane for the production of fuels and chemicals appears to be near, but current economic uncertainties limit the amount of research activity and the implementation of emerging technologies.     

加氢处理装置循环氢中甲烷含量变化分析及应对措施

针对加氢处理装置脱硫后循环氢中甲烷含量变化原因进行了分析。结果表明,加氢处理装置补充新氢中甲烷含量增大,反应温度升高,反应器新加入较高活性催化剂FF-24,均会引起脱硫后循环氢中甲烷含量增大。当原料油密度892～909kg/m3时,组分变化较小,对脱硫后循环氢甲烷含量影响不大。为了控制脱硫后循环氢甲烷含量,可以适当增大排废氢量以减少甲烷积累;在满足生产条件情况下,适当提高新氢纯度和降低反应温度;控制冷高分温度在40～50℃,以保持甲烷在冷高分液中一定的溶解度。     

Biohydrogen Production Through Dark Fermentation

Waste organic biomass is regarded as the most suitable renewable source for conversion to produce biofuels and biochemicals. Owing to its high-energy potential and abundancy, lignocellulosic biomass can be utilized to produce alternative energy in the form of gaseous and liquid biofuels. Microbial conversion of waste biomass is the most successful technology for the generation of biohydrogen through dark fermentation. Different biological hydrogen production technologies along with process parameters are described in this review paper with the focus on dark fermentation. The production of biohydrogen from various substrates is summarized along with the integrated mode of dark fermentation and photofermentation. Hydrogen generation through biological water-gas shift reaction is also highlighted.     

甲烷催化裂解制氢和碳纳米材料研究进展

甲烷通过催化裂解反应可生成不含碳氧化合物（CO_x）的高纯氢和碳纳米材料（如碳纤维或碳纳米管等）,对我国能源结构的调整及新材料的应用具有重要意义。与其他制氢工艺相比,甲烷催化裂解制氢工艺具有反应过程简单、产物清洁无污染、反应成本低等优点,因此该工艺具有重要的工业应用前景。本文重点阐述了催化剂（活性组分、催化剂载体、制备方法等）以及反应条件（催化剂还原条件、空速、反应温度等）对甲烷转化率、氢气产率和碳纳米材料（形貌和产量）的影响并对甲烷催化裂解反应机理、催化剂的失活与再生进行了概述。甲烷催化裂解反应目前仍处于实验室研究阶段,高效催化剂的研制以及流化床反应器的优化是该反应实现工业化应用的必要前提。     

Dry anaerobic batch digestion of the organic fraction of municipal solid waste

Anaerobic digestion at high solid concentrations (dry anaerobic digestion) is an attractive method for the stabilization of solid organic wastes. A new concept for dry anaerobic batch digestion (BIOCEL) of the organic fraction of municipal solid waste is presented. The start up of a BIOCEL reactor was studied with several methods of process set up and operation. Dry anaerobic digestion of the pure undiluted organic fraction obtained from a shredding/separation process was not accelerated by partial spatial separation of substrate and methanogenic inoculum (granular sludge) or leachate recycle, or both. With these three methods after 30 days the high organic acids concentration and low pH in the reactor indicated a sour reactor, unable to establish significant methane production. When the organic fraction was digested in combination with compost addition (40% (w/w) of the initial solids) and leachate recycle, the stabilization rate increased significantly. Leachate recycling in combination with partial spatial separation of the substrate/compost mixture and the inoculum showed the shortest lag phase in the methane production and the shortest digestion time. When the digested residue of a completed digestion was applied as the methanogenic inoculum (40% (w/w) of the initial total solids) the digestion time was slightly shorter. It is concluded that dilution with compost had a positive effect on the start up of the dry anaerobic digestion and compensated for a suboptimal amount of initial methanogenic biomass. During the start up of dry anaerobic batch digestion of municipal solid waste the rapid recovery of methane formation from an initial overloading was observed and was found to be the result of a population shift in the methanogenic biomass and the existence of zones in the reactor with more optimal conditions (higher p H, lower organic acids concentration). The observed digestion time was 36 days. Recommendations are given to shorten the period needed, for complete digestion.