Solar assisted biogas plants IV A: Experimental validation of a numerical model for slurry temperature in a glazed fixed-dome biogas plant

The paper presents a comparison between the theoretical and experimental temperatures of digester slurry in a glazed fixed-dome biogas plants. The agreement is within ±2.6°C except for an instance of 4.2°C in the month of April 1988.     

沼气发动机驱动的热泵能源利用率计算

沼气发动机驱动的热泵(BHP)是一种节能环保型装置,与电动压缩式热泵相比,其主要动力源不同.该装置能充分回收利用沼气发动机余热.通过对BHP系统的构建及一次能源利用率(PER)的计算,分析了BHP系统的经济性及其对环境保护的作用.结果表明:不论从节能还是从环保方面考虑,BHP系统都具有明显的经济价值和环保效益.     

用于生态工业园的冷热电联产系统

基于能的梯级利用原理,提出了一种用于生态工业园的冷热电联产系统。园区产生的生活垃圾通过厌氧消化产生沼气来发电,柴油机排放的烟气用于吸收式制冷和生活用热水,缸套水废热用于除湿。研究表明,新系统具有更优良的热力性能,化石能源的相对节能率达到34%,比原系统高14个百分点。沼气发电节省了1.5%的重油,低品位废热除湿提供了42%的冷负荷,节省了原系统中空调的电耗。能的梯级利用原理在液体除湿中的应用以及化石能源与可再生能源综合互补能够使生态工业园获得优良的节能效果。     

分散原料沼气集中供气运行分析

我国规模化沼气工程存在原料单一、产气率低、装备落后等技术瓶颈,西南地区沼气原料来源分散、成分复杂,因此需要开发新的多种原料混合发酵的新模式来提高沼气工程厌氧消化效率。本工程通过全混式厌氧发酵两级工艺共同厌氧消化如秸秆和畜禽粪便等分散原料,形成新的沼气和发酵剩余物利用模式。结果表明,在30 d稳定运行期间,600 m³厌氧发酵罐每天可消纳猪粪7.9 t、浓污水8.2 t及农作物秸秆0.2 t,日产气量为900 m³,混合原料发酵的容积产气率达1.5 m³/(m³∙d)。     

利用沼气技术治理大中型畜禽场污染

利用厌氧消化技术处理禽畜场有机废弃物是对废弃物进行减量化、资源化和无害化处理的一项重要措施。 沼气工程的环境效益体现在输入部分和输出部分两个方面,在输入部分,通过对畜禽粪便进行厌氧消化,减少了污染,承担了社会成本,应当得到一定的补偿。在输出部分,用沼气发电可以替代常规电力,减少有害气体排放,同样应该得到支持和鼓励。     

Comparative evaluation of batch and continuous process biogas production from animal wastes

The production of biogas, an alternative source of energy from animal wastes, was investigated in the laboratory scale using the simple single-state digesters. In this study, a comparison between two feed processes, a batch feeding process and a continuous feeding process, both within mesophilic temperature ranges was carried out. The digesters were fed with mixture of cow dung and poultry droppings and operated at ambient temperature of 30°C as baseline and temperatures of 32?45°C for 30 days. In this study, the optimum temperature for biogas production from the blends of the animal wastes was determined as controlled heat was supplied to the digester. Results obtained indicate maximum biogas yield of 3.603 litres from the digestion of the animal wastes at temperature of 370°C in the continuous process while maximum biogas yield of 2.685 litres was obtained at temperature of 400°C for the batch process.     

The feasibility of liquefied biomethane as alternative fuel: a comparison between European and Chinese markets

ABSTRACT

Natural gas is considered the alternative fuel that, in the short-medium term, can best substitute conventional fuels, in order to reduce their environmental impact. The purpose of this paper is to outline the feasibility of liquefied natural gas (LNG), especially from biogas (LBG), as vehicle fuel in Europe and in China. Firstly, the analysis presents the difficulty of methane supply in some regions and the need for feasible ways of producing LNG. For this purpose, biogas recovery and its upgrade are presented as an interesting source to produce such alternative vehicle fuel, being also a renewable source with a reduced environmental impact. Secondly, an economic analysis is performed for a specific European country (Italy): it takes into account technical aspects, costs, the foreseen market price for the new fuel and the necessary incentive policy. The latter aspect has been revealed to cover a major role for the feasibility of such projects.     

利用微生物技术改良泥炭土工程性质试验研究

提出利用微生物技术制备原生菌高浓度菌液,用来加快土中有机质分解速率,实现在较短时间内显著降低有机质含量、改善土的工程性质的目的。为验证其可行性,从昆明市2个场地采取了泥炭土样,研发了2套模型装置,分别模拟厌氧、好氧环境下泥炭土有机质分解过程,并测试分析了分解后泥炭土的烧失量、界限含水率及一维固结蠕变特性。试验结果表明:厌氧环境下,菌液浸泡的泥炭土生物气产量比纯水浸泡的有大幅度提高,其产气动力学特征符合修正Gompertz模型。好氧环境下,分解30 d左右时,2个场地泥炭土烧失量分别减少了10.3%和15.6%,减少量比厌氧环境下的大。界限含水率试验表明,泥炭土液限随微生物分解反应时间的增长有所降低,而塑限变化幅度不大。一维固结蠕变试验表明,有机质分解后的泥炭土次固结系数下降,分解时间越长,次固结系数下降越显著。对新技术的特点进行了分析,并对其理论及应用研究进行了展望;该技术有望发展为一项生态友好型的泥炭土地基新型处理方法,改良泥炭土有望成为微生物岩土技术一个潜在应用领域。     

Upgrading biogas into syngas via bi-reforming of model biogas over ruthenium-based nano-catalysts synthesized via mechanochemical method

The upgrading of biogas to value-added syngas via reforming of biogas is of great significance from the perspective of green carbon science. A series of Ru based nano-catalysts (Ru/MgO, Ru/La₂O₂CO₃, Ru/CeO₂) with relatively low Ru loading and high dispersion were successfully prepared by mechanochemical method, and applied in the bi-reforming of model biogas reaction. The representative catalysts were comprehensively characterized by XRD, N₂ physical adsorption, ICP-OES, SEM, XPS, H₂-TPR, CO₂-TPD, HRTEM, FTIR of CO adsorption, TPSR, TG, and Raman spectroscopy, etc. Ascribed to the appropriate basicity of MgO, homogeneous Ru dispersion with ultra-small particle size, and strong interaction between Ru ultra-small nano particles and MgO support, Ru/MgO exhibit higher CO₂ adsorption and activation, higher CH₄ activation and dissociation, compared with Ru/La₂O₂CO₃, Ru/CeO₂, which facilitate the formation of active oxygen species and intermediate coke removal, thus enhance the resistance to coke deposition and sintering. At reaction conditions of T = 750 °C and weight hourly space velocity = 32,400 mLg_Cat⁻¹ h⁻¹, 0.5Ru/MgO catalyst exhibit satisfying catalytic activity (initial CH₄/CO₂ conversation rate of 87/48%) and superior stability (stable for 150 h) with negligible deactivation rates.     

鄂尔多斯盆地乌审旗地区煤层气富集主控因素及其勘探方向

乌审旗地区是鄂尔多斯盆地的重要含煤区,也是近几年低煤阶煤层气勘探的热点地区。但该区前期煤层气钻探总体效果并不理想,迫切需要认清该区煤层气富集规律,以便有效开展煤层气勘探及开发利用。为此,对该区煤层分布特征、聚煤期沉积环境、煤岩特征及储层物性、煤层含气性等地质条件进行了分析,发现该区煤岩演化程度低,以低煤阶长焰煤为主,煤层厚5~30 m,大部分地区煤层埋深小于1 000 m且分布稳定,具有一定的煤层气勘探潜力。但煤层气钻井揭示该区煤层含气性变化大,煤层含气量介于0.19～6.7 m³/t,部分地区煤层气组成中CH₄含量小于25%,说明煤层早期成岩时生成吸附的甲烷已被破坏逸散。进一步分析影响该区煤层气富集的主控因素后认为：在煤层直接盖层为砂岩、保存条件差的地区,煤层含气性差,反之,则含气性好,如果有后期生物气的补充,则可以富集成藏。最后指出：该区北部的乌审召区块和南部的纳林河区块,煤层气保存条件好、含气量高、勘探潜力大,可作为下一步煤层气勘探的有利目标区。