Effect of temperature and retention period on biogas production from lignocellulosic material

The extensive utilization of biogas for energy needs of rural dwellers would reduce their dependence on fossil fuels and fuelwoods and henoe camplement Government afforestation programes. In this investigation, effect of temperature and retention period on biogas production from lignooellulosic material, hereafter referred to as cow dung were studied. Maximum gas production was dotained at thermophilic temperature. The results of the effect of retention period shows that gas production was qotimum at 4th and 7th weeks of production.     

Modelling of multicomponent gas separation with asymmetric hollow fibre membranes—methane enrichment from biogas

A mathematical model for the dynamic performance of gas separation with high flux, asymmetric hollow fibre membranes was developed considering the permeate pressure build‐up inside the fibre bore and cross flow pattern with respect to the membrane skin. The solution technique provides reliable examination of pressure and concentration profiles along the permeator length (both residue/permeate streams) with minimal effort. The proposed simulation model and scheme were validated with experimental data of gas separation from literature. The model and solution technique were applied to investigate dynamic performance of several membrane module configurations for methane recovery from biogas (landfill gas or digester gas), considering biogas as a mixture of CO₂, N₂ and CH₄. Recycle ratio plays a crucial role, and optimum recycle ratio vital for the retentate recycle to permeate and permeate recycle to feed operation was found. From the concept of two recycle operations, complexities involved in the design and operation of continuous membrane column were simplified. Membrane permselectivity required for a targeted separation to produce pipeline quality natural gas by methane‐selective or nitrogen‐selective membranes was calculated. © 2012 Canadian Society for Chemical Engineering     

高温高压条件下微生物驱油微观机理研究

采用微观透明可视仿真刻蚀储层模型,研究了3株产表面活性剂较多的好氧菌W18、DM-2和SH-1,2株产生物气较多的厌氧菌L1、4F,在高温高压条件下(65℃,10 MPa)驱油时形成的残余油状态,结合大量微观照相图讨论了驱油机理。5株菌在高温高压油藏中均能存活,驱油性能较好。生物气驱机理包括:气驱,气液界面滑动,原油膨胀降黏,气泡贾敏效应扩大水驱波及体积及气体进入盲端驱油。生物表面活性剂驱油机理包括:乳化分散剩余油,降低油水界面张力,剥离油膜。微生物降解原油也是驱油机理之一。图28表1参4。     

松辽盆地滨北地区生物气资源量预测

松辽盆地滨北大部分地区中浅层的烃源岩有机质成熟度较低，常规油气资源将相当有限，生物气是通过微生物食物链反应而成气，在埋藏很浅的时候就开始形成生物气，因此成熟度较低恰好是适合生物气的生成条件。文章对源岩的发育、分布、埋深、地层温度、母质输入类型、稳定碳同位素组成等特征进行分析后认为，滨北地区有形成生物气的良好条件，应用同柴达木盆地和莺琼盆地进行类比的方法，确定生化甲烷产气率和生物气聚集系数，通过对滨北地区生物气资源量的计算，认为滨北地区不仅具有生物气的生成条件，而且具有一定的资源潜力。     

沼气压缩罐装技术的试验研究

通过采取沼气净化技术,去除沼气中无效组分,提高沼气热值,最大化满足沼气乐缩技术要求.通过采用多级压缩技术,实现沼气的压缩罐装,为进一步开展沼气罐装技术的深层次研究提供参考.     

The kinetics of anaerobic digestion of farm wastes

The conversion of animal excreta and similar feedstocks to biogas in single-stage, continuous-flow anaerobic digesters running in steady-state conditions can be described in terms of undegradable material and hydrolysis and fermentation of two solid components plus conversion of acid and hydrogen plus carbon dioxide to methane. These reactions, while linked in provision of substrates for the different bacterial groups, can be regarded as separate continuous-cultures, each with one limiting substrate, but with nitrogen in excess. The substrate utilisations can then be described by simple kinetic equations applicable to bacterial growth in pure-culture chemostats. The degradation of solids is the overall rate-limiting reaction and the use of two biodegradable solids, distinguished more by particle size than by chemical composition, explains some apparent anomalies in solids degradation and gas production at different retention times. While the general principles apply to any waste, the values of constants used in the equations depend on the solids in a particular feedstock. Temperature effects on digestion are explained by using a recently-suggested formula for modification of the maximum growth rates of the bacteria with temperature. This distinguishes between mesophilic and thermophilic digestions. Inhibitory effects of ammonia and high input solids concentrations can also be described by modification of maximum bacterial growth rates.     

Solar assisted biogas plant IIA: Experimental validation of the mathematical models for floating drum type biogas plant

The theoretical predictions presented in an earlier paper for the performance of solar assisted biogas plants are compared with experimental measurements made on four separate systems. There is good agreement between the results and the theoretical predictions.     

去除牛粪厌氧生物转化过程中的H2S

The main aim of this research was the experimental study at lab scale to check the absorption technology for the in situ removal of H2S from biogas during anaerobic digestion process. The reagent FeCl3 was used to check the removal efficiency of H2S produced from dairy manure during anaerobic bioconversion process. The experiments were conducted under mesophilic conditions. The composition of biogas was analyzed by gas chromatography analyzer equipped with flame photometer and thermal conductivity detectors. Experimental results under the same conditions demonstrate that high concentration of H2S in the form of FeS can be removed totally from the biogas using FeCl3 dosing with in anaerobic batch digester.     

太阳能甲烷重整反应的研究进展

太阳能甲烷重整反应是天然气、沼气和太阳能综合开发、合理高效利用的有效途径。从能量存输系统、太阳能重整器和催化活性吸收体三方面简述了太阳能甲烷重整反应系统的研究现状,并对其发展前景进行了展望。