基于层次分析法和熵权法的中小型沼气工程净化提纯技术筛选

文章构建了3层次13指标的沼气提纯技术综合评价体系,并运用层次分析法和熵权法从技术成熟度、产品气性能、设备适应性、环境指标和经济指标5个方面对13个指标进行了权重排序,得出最重要的3项指标分别为产品气纯度、甲烷回收率和对不同来源沼气的适应性,其权重分别为0.179 6,0.111 1和0.105 4。在该评价体系的基础上,采用模糊综合评价法对5种常用沼气提纯技术进行适合中小型沼气工程提纯系统应用的排序,得出其顺序为膜分离法、变压吸附法、化学吸收法、物理吸收法、深冷分离法。层次分析法和熵权法的综合使用,减弱了层次分析法的主观性影响,避免了熵权法偏离实际生产的可能,为沼气提纯技术的筛选提供了一种科学的方法。     

沼气净化技术处理酒厂废水的研究

分析和讨论了沼气净化技术处理酒厂废水的混合型工艺路线，它采用人工接种培养甲烷菌颗粒污泥，     

硫酸亚铁脱硫液和石灰乳净化沼气的实验研究

一、前言大中型沼气工程都存在着沼气脱硫问题,目前国内大多采用固体脱硫剂。以禽畜粪便作发酵原料所产沼气中的硫化氢含量一般在1mg/L以下,采用干法脱硫能取得较好的净化效果,但脱硫剂只能维持2～3月就需再生更换,利用率低,且脱硫设备笨重,再生更     

沼气净化技术处理生猪养殖场废水

介绍了实际运行的生猪养殖场沼气工程,根据生猪养殖场废水的特性,选择沼气净化技术处理生猪养殖场废水;采用厌氧好氧工艺,日平均处理COD浓度4 060 mg/L,SS 3 100 mg/L的有机废水80～100 t;COD去除率为99.8%,SS去除率为98%,达到国家规定的排放标准.     

基于模糊层次分析法的风电场优化选址决策

风电场选址时存在对多种备选方案进行选择的问题,文章从多角度出发,选取地理、技术、经济、环境因素,提出了基于模糊层次分析法的解决方案,构建风电场选址的递阶层次结构。以三角模糊数互补判断矩阵为基本的数学模型,构造因素的比较判别矩阵以及方案的优先矩阵;通过将三角模糊数互补判断矩阵转化为精确数矩阵,对其进行一致性的判定和改进,计算出各因素权重,对备选方案进行单因素排序以及综合排序。并通过实例分析,验证了该方法在风电场选址决策中的有效性和正确性。     

沼气电站工艺设计的研究

就沼气电站的工艺设计系统所涉及的特殊要求,从沼气电站设备选型及容量、沼气系统、通风系统、润滑油系统、冷却系统、排烟系统和机组起动及设备布置等方面进行了探讨研究,可为沼气电站工程的工艺设计提供参考;也可为建造其他燃气电站工程提供设计计算模式。     

高压水洗沼气净化吸收塔的模拟研究

运用Aspen Plus软件对沼气高压水洗净化工艺中的吸收塔进行了模拟计算。选用RadFrac单元操作模型,采用NRTL热力学性质计算方法,对吸收塔的填料高度和吸收剂用量进行了初步设计,在一定操作条件下考察了塔顶、塔底组成和塔内流量、温度及组成分布的情况、吸收过程中压强、吸收剂用量及吸收塔填料高度对净化后生物甲烷纯度的影响。模拟数据对实际应用具有指导意义。     

基于多目标模糊层次分析法的厂级负荷分配研究

文中以电厂节能减排为先导,结合目前国内600MW主流机组为研究对象,建立了基于经济性、快速性、环保性的多目标厂级负荷优化分配数学模型。结合现场数据获得了机组煤耗率与大气污染物排放特性曲线,进而利用模糊决策理论与模糊层次分析法进行多目标问题的建模。在此基础之上,以动态规划方法作为优化算法,借助MATLAB软件对多目标优化模型进行了算例仿真,并且对仅以最小煤耗率为目标的单目标优化方案与多目标优化方案进行了对比分析。仿真结果表明:采用模糊层次分析法的多目标优化方案在经济性与环保性方面优于单目标优化方案。     

城镇生活污水沼气净化技术的应用推广

中小城镇生活污水沼气厌氧净化是具有中国特色的小型分散化污水治理技术，具有投资少，效果好，运行无需能源支持等特点，经过不断完善，目前该技术已基本成熟，在一些省、市的试范推广应用中，其成效非常显著。文章通过对国内外生活污水净化技术的研究，结合安徽省几年推广普及该项技术的工作实践，阐述了该项技术推广应用遇到的一些问题和制约其发展的若干因素，提出发展对策。     

水电工程环境影响评价的系统层次分析模糊优化模型

以模糊集理论和系统分析的基本观点为基础，将环境系统分为若干层次，运用模糊优化理论，提出了水电工程环境影响评价的系统层次分析模糊优化模型，并以龙滩水电工程为实例进行了演算．计算成果与多级模糊综合法的评价结果相比较知前者更严谨、清晰．     

Production and purification of hydrogen by biogas combined reforming and steam-iron process

Cobalt ferrite and hematite with minor additives have been tested for production and purification of high purity hydrogen from a synthetic biogas by steam-iron process (SIP) in a fixed bed reactor. A catalyst based in nickel aluminate has been included in the bed of solids to enhance the rate of the reaction of methane dry reforming (MDR). The reductants resulting from MDR are responsible for reducing the oxides based on iron that will, in the following stage, be oxidized by steam to release hydrogen with less than 50 ppm of CO. Coke minimization along reduction stages forces to operate such reactors above 700 °C for reductions, and as low as 500 °C for oxidations to avoid coke gasification. To avoid problems such as reactor clogging by coke in reductions and/or contamination of hydrogen by gasification of coke along oxidations, steam in small proportions has been included in the feed with the aim of minimizing or even avoiding formation of carbonaceous depositions along the reduction stage of SIP. Since steam is an oxidant, it exerts an inhibiting effect upon reduction of the oxide, that slows down the efficiency of the process. It has been proved that co-feeding low proportions of steam with an equimolar mixture of CH₄ and CO₂ (simulating a poor heating value desulphurized biogas) is able to avoid coke deposition, allowing the operation of both, reductions and oxidations, in isothermal regime (700 °C). Empirical results have been contrasted with data found in literature for similar processes based in MDR and combined (or mixed) reforming process (CMR), concluding that the combination of MDR + SIP proposed in this work, taking apart economic aspects and complex engineering, shows similar yields towards hydrogen, but with the advantage of not requiring a subsequent purification process.     

基于GRNN的生物质真空热解液化过程优化研究

以油菜秸秆为原料,采用真空热解系统进行了制取生物油的正交试验研究,基于广义回归神经网络(GRNN)原理,建立了以热解终温、体系压力、升温速率和保温时间为输入变量,生物油产率和能量转化率为输出变量的预测模型,并以生物油产率和能量转化率为目标开展了系统参数的优化,对优化结果进行了试验验证。研究结果表明,经训练后的GRNN预测模型输出的生物油产率和能量转化率的预测值与试验值吻合较好;当热解终温为486.8℃、体系压力为5.0 kPa、升温速率为18.1℃/min、保温时间为55.0 min时,最高生物油产率和能量转化率分别为43.6%和35.5%。经试验验证,优化结果较为精确。     

Regulation and optimization of the biogas process: Propionate as a key parameter

The use of volatile fatty acids (VFA) as process indicators in biogas reactors treating manure together with industrial waste was studied. At a full-scale biogas plant, an online VFA sensor was installed in order to study VFA dynamics during stable and unstable operation. During stable operation acetate increased significantly during the feeding periods from a level of 2–4 to 12–17 mM, but the concentration generally dropped to about the same level as before feeding. The fluctuations in the propionate were more moderate than for acetate but the average level rose during 1 week of operation from 0.6 to 2.9 mM. A process disturbance caused by overloading with industrial waste was reflected by a significant increase in all VFA concentrations. During the recovery of the process, the return of propionate back to the steady-state level was 2–3 days slower than any other VFA and propionate could best describe the normalizing of the process. In a lab-scale continuously stirred tank reactor experiment, with manure as main substrate, the prospective of using either propionate concentration or methane production as single process indicators was studied. Propionate was found to be the best indicator. Thus, a process breakdown caused by organic overloading with meat and bone meal and lipids was indicated by changes in propionate concentration 12–18 days before a decrease in methane production was observed. Furthermore, a more efficient and stable utilization of the substrate was observed when propionate was used as process indicator.     

压力水洗法沼气脱碳的模拟研究

采用PRO II 8.0电解质模型模拟了压力水洗法沼气脱碳单元的运行成本和CH_4回收率,要求净化气CO_2浓度3.0%,CH_4收率96%。通过改变进口浓度、吸收塔理论板数、吸收压力、吸收温度、闪蒸压力和再生气-液比,模拟对运行成本和收率的影响。结果表明:高理论板数、低温、高压、高闪蒸压力有利于降低运行成本。吸收压力为0.8 MPa,吸收温度为5℃,闪蒸压力为0.35 MPa时,沼气压力水洗脱碳单元的运行成本为14.4分/m~3,CH_4回收率可以达到98.4%。     

甘氨酸钠溶液提纯沼气性能的试验研究

对新型有机胺-甘氨酸钠溶液吸收CO2提纯沼气的适宜条件进行了试验研究,并采用加热再生的方法对甘氨酸钠溶液的再生性能进行了研究。考察了不同浓度(0.5～3 mol/L)甘氨酸钠溶液对CO2吸收速率和吸收负荷随时间的变化关系,气流速度对于甘氨酸钠溶液对CO2吸收速率和吸收负荷的影响以及温度对于甘氨酸钠溶液对CO2吸收速率的影响。试验结果表明,甘氨酸钠溶液的浓度越高,吸收量也越大,但吸收负荷越小;气流速度对甘氨酸钠吸收CO2速率影响较为明显;温度对甘氨酸钠吸收CO2速率影响较小。另外,甘氨酸钠溶液具有稳定的再生性能,适宜的再生温度和再生时间分别为108℃和3 h。     

Cost-benefit analysis of different hydrogen production technologies using AHP and Fuzzy AHP

In this paper, cost-benefit analysis is performed to compare eight different hydrogen production technologies using the classical analytic hierarchy process (AHP) and the Fuzzy AHP. The technologies considered are steam methane reforming, coal gasification, partial oxidation of hydrocarbons, biomass gasification, photovoltaic-based electrolysis, wind-based electrolysis, hydro-based electrolysis, and water splitting by chemical looping. For each of the hydrogen production technologies, five criteria are used for evaluation: greenhouse gas emissions, raw material and utilities consumption, energy efficiency, scalability, as well as waste disposal and atmospheric emissions. The results obtained for benefits category using AHP and Fuzzy AHP are plotted against the normalized equivalent annual costs of each technology. It is concluded that the fossil fuel based processes appear to have less beneficial qualities including greater environmental impacts, but are more cost-effective. On the other hand, the renewable based processes appear to have more benefits as well as being more expensive for hydrogen production. However, the cost-benefit analysis results imply that the process of water splitting by chemical looping among the renewable approaches is the most promising new technology.     

Hydrogen purification layered bed optimization based on artificial neural network prediction of breakthrough curves

Artificial neural network has generally been used for a quantity of tasks such as classification, prediction, clustering and association analysis in different application fields. To the best of our knowledge, there are few researches on breakthrough curve used artificial neural network. In this paper, an artificial neural network model is established for breakthrough curves prediction in relation to a ternary components gas with a two-layered adsorbent bed piled up with activated carbon (AC) and zeolite, and an optimization is concluded by the artificial neural network. The performance data which acquired by Aspen model has been utilized for training artificial neural network (ANN) model. The ANN model trained has great competence for making prediction of hydrogen purification performance of PSA cycle with impressive speed and rational accuracy. On the strength of the ANN model, we implemented an optimization for seeking first-rank PSA cycle parameters. The optimization is concentrated on the effect of inlet flow rate, pressure and layer ratio of activated carbon height to zeolite height. Furthermore, this paper shows that the PSA cycle's optimal operation parameters can be obtained by use of ANN model and optimization algorithm, the ANN model has been trained according to the data generated by Aspen adsorption model.     

沼气物业化管理模式研究

随着农村沼气池和沼气用户数量的增多,实行沼气物业化管理服务成为主要发展趋势.文章概述了沼气物业化管理的内涵和特征,分析了现阶段沼气物业化管理模式的运行机制和存在问题,最后提出促进沼气物业化管理的思路、模式和建议,为指导当前沼气物业化管理提供了新的视角和依据.     

Simulative optimization of catalyst configuration for biogas dry reforming

Biogas dry reforming is a promising technology for converting biomass into high-value products and reducing greenhouse gas emissions. Recent improvements to biogas reforming have mainly focused on the preparation of functional catalysts; however, little attention has been paid to the effects of catalyst configuration in plug flow reactors. In this study, a Ni/MgO catalyst for biogas reforming was synthesized via the wet impregnation method. Parameters were optimized using an experimental rig and then simulations were performed using an Aspen HYSYS reaction simulator. We simulated loading the same amount of catalyst into 1, 2, 3, or 10 zones inside the reactor and compared performance parameters, including H₂ yield, CO yield, CH₄ conversion, and CO₂ conversion. The results of simulations showed that a 2-zone configuration with a catalyst ratio of 1:4 was optimal, with 88.2% H₂ yield, 83.5% CO yield, 96.4% CH₄ conversion, and 91.7% CO₂ conversion. Catalyst zone number, catalyst distribution, and catalyst zone position all had significant effects on catalytic behavior. The findings of this study provide new insights into the processes of biogas reforming and other heterogeneous catalysis reactions.     

基于改进AHP法的水闸安全性模糊综合评价

针对水闸安全评价体系中存在定性指标多、指标权重无固定标准及专家主观因素等问题,引进基于指标重要性分值和熵权理论相结合的改进层次分析法(AHP),利用中间型柯西分布确定隶属度函数,并结合模糊综合评价理论对水闸指标体系进行安全评价。实例表明,该方法合理、可行且易于操作。