利用微生物好气性分解产生热能

生物质(Biomass)作为能源利用的转换技术有许多种,沼气发酵可使生物物质转换成气体燃料(沼气);酒精发酵可使生物物质转换成液体燃料(酒精)。这两种发酵都是微生物在厌氧的条件下进行的。参与作用的微生物,主要是厌氧性微生物或兼性厌氧性微     

玉米秸秆与猪粪混合发酵产沼气及其细菌解析

以总固体1∶1的玉米秸秆和猪粪为混合原料,采用10 L厌氧反应器进行批式全混中温沼气发酵,并利用454焦磷酸测序法测定混合发酵过程中细菌群落变化。结果表明:预处理玉米秸秆和猪粪混合沼气发酵启动迅速,在第4天达到产气高峰,容积产气率为1.17 L/(L·d),46 d原料沼气产率为356.55 m L/g VS。该混合发酵系统中共有23~27门细菌,其中优势菌群为拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)和变形菌门(Proteobacteria)。发酵期内的Shannon指数在4.88~5.53之间,说明发酵期内细菌多样性比较稳定。     

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)。     

葡萄籽提油前后发酵产沼气潜力研究

在恒温25℃条件下,采取批量发酵工艺,研究了葡萄籽提油前后产沼气潜力。结果表明:葡萄籽TS,VS发酵产沼气的潜力分别为473.65 mL/g和484.55 mL/g,能源转换效率为37.25%;葡萄籽油枯TS,VS发酵产沼气的潜力分别为450.03 mL/g和460.44 mL/g,能源转换效率为36.43%。     

浅谈沼气发酵

一前言沼气发酵又称厌氧消化,是在厌氧环境中微生物分解有机物最终生成沼气的过程,其产品是沼气和发酵残留物(高效的有机肥)。沼气发酵是生物质能转化最重要的技术之一,它不仅能有效处理有机废物,降低化学需氧量(COD),还有杀灭致病菌,减少蚊蝇孳生的功能。此外,沼气发酵作为废物处理的手段,不仅能耗省,还能产生优质的燃料沼气和肥料。     

多元原料混合发酵制备沼气技术研究进展

目前,我国沼气的发酵原料主要是禽畜粪便和农作物秸秆,随着厌氧发酵技术的发展,更多种类废弃物也逐步受到人们的关注。有机废弃物沼气化利用在我国生态文明建设中有着重大意义。论文综述了我国生物质资源,如禽畜粪便、农作物秸秆、农产品加工废弃物、市政有机废弃物和能源作物的特性和作为沼气发酵原料的优缺点,比较了这些原料的沼气生产潜力,探讨了混合原料发酵技术及重要的几种沼气发酵外源添加剂。     

农村秸秆与粪便发酵产氢的研究

选取10种常见的农业有机废弃物:稻草、玉米秆、小麦秆、大麦秆、蚕豆秆、黄豆秆等秸秆以及猪粪、牛粪、鸡粪、马粪等粪便作为原料,采用批量发酵工艺,控制发酵料液的pH值在适宜范围内,进行厌氧发酵产氢的研究.试验结果表明,在厌氧条件下,采用批量发酵工艺,控制发酵温度为25℃左右,以农作物秸秆、畜禽粪便为原料,以沼气发酵后的厌氧活性污泥为天然产氢菌种的来源,以乳酸调控发酵料液pH值为4.5～5.5,可以获得洁净能源--氢气.     

木薯酒精废醪产氢潜力的试验以及对产氢产甲烷联合发酵的研究

以木薯酒精废醪为原料,通过调节pH值至5.0,在(35±1)℃的中温条件下进行批量式沼气发酵实验,发酵料液的TS浓度设为6%。实验结果表明,氢气发酵试验的运行时间为11 d,净产气量为1615 mL,产氢潜力为92.13 mL/g(TS)、97.58 mL/g(VS),能源转换效率为1.58%。针对产氢发酵和产甲烷发酵能源转换效率低这一问题,对产氢、产甲烷联合发酵进行了分析,讨论了原料种类、接种量、温度、pH值、发酵浓度、氢气分压等参数对联合厌氧发酵的影响以及对发酵过程中动力学和菌群的探讨,并对以厌氧产氢产甲烷联合发酵的方法处理木薯酒精废醪进行了讨论。研究结果可为以后木薯酒精废醪的能源高效利用提供参考。     

从废水中回收能源--微生物燃料电池和发酵生物制氢技术

利用微生物在废水处理的同时获得能量主要有3种方式,分别是厌氧产沼气,发酵生物制氢和微生物燃料电池技术.利用厌氧微生物处理污水,在去除COD的同时获得沼气是比较成熟的技术,而后两种的研究开展较晚,仍处于实验室研究阶段.但微生物燃料电池和发酵生物制氢技术发展迅速,而且可以有机结合.文中对两者的基本原理和最新研究进展进行了介绍,并对其发展前景进行了展望.     

沼气

沼气,顾名思义就是沼泽里的气体。沼气是有机物质在厌氧条件下,经过微生物的发酵作用而生成的一种可燃气体。由于这种气体最先是在沼泽中发现的,所以称为沼气。人畜粪便、秸秆、污水等各种有机物在密闭的沼气池内,在厌氧（没有氧气）条件下发酵,     

生物质电厂节能降耗改造能值分析

以某生物质电厂为研究对象,应用能值理论,借助能值转换率η_(Tr)、能值产出率η_(EYR)、环境负载率η_(ELR)、能值可持续指数η_(ESI)等指标,对企业主要耗能设备降耗改造进行能值分析。研究结果表明:烟气余热回收技术改造后的能值转换率最低,但是环境负载率也最高,所有的改造技术都能提高能值产出率,除了烟气余热回收技术,其余节能技术在能源可持续指标上都有良好的表现。综合考虑经济效益和污染等问题,烟气余热回收虽然有很好的节能效果,但是会对环境造成一定的污染,而光伏水泵发电和变频改造技术则具有较为平衡的效果。     

太阳能烟囱发电新技术

介绍了一种太阳能烟囱发电新技术。太阳光辐射透过太阳能集热棚，加热集热棚下面的地面，被加热的地面与集热棚内的空气进行热量交换，使其温度上升，被加热的空气上升并进入与集热棚中部相连的烟囱，在烟囱内上升气流推动涡轮发电机旋转、发电。整个太阳能烟囱发电技术的能量转化以及效率可以从三个部分来分析：通过集热棚太阳能转化为空气热能，通过烟囱将热能转化为动能，通过涡轮发电机将动能转化为电能。另外，总结了太阳能烟囱发电技术的优缺点，指出它是一种适合于我国西部地区的一种能源开发新途径。     

千瓦级小型液压式波浪能装置能量转换系统研究

针对小型海洋观测仪器用电需求,研究高效、可靠的小型液压式波浪能装置能量转换系统。在实验室建立一套3 kW的液压式波浪能能量转换系统,进行不同电阻负载、不同蓄能体积以及不同控制策略的液压系统试验,获得PTO效率曲线及各发电过程的特性曲线,详细分析不同控制策略的能量转换特性,得到PTO效率随阻值的增大趋于平稳、蓄能体积基本不影响PTO转换效率的结论,验证有蓄能器无控制器型直冲式能量转换系统的可行性。     

Assessing the impacts of technology improvements on the deployment of marine energy in Europe with an energy system perspective

Marine energy could play a significant role in the long-term energy system in Europe, and substantial resources have been allocated to research and development in this field. The main objective of this paper is to assess how technology improvements affect the deployment of marine energy in the EU. To do so the linear optimization, technology-rich model JRC-EU-TIMES is used. A sensitivity analysis is performed, varying technology costs and conversion efficiency under two different carbon-emissions paths for Europe: a current policy initiative scenario and a scenario with long-term overall CO₂ emission reductions. We conclude that, within the range of technology improvements explored, wave energy does not become cost-competitive in the modelled horizon. For tidal energy, although costs are important in determining its deployment, conversion efficiency also plays a crucial role. Ensuring the cost-effectiveness of tidal power by 2030 requires efficiency improvements by 40% above current expectations or cost reductions by 50%. High carbon prices are also needed to improve the competitiveness of marine energy. Finally, our results indicate that investing 0.1–1.1 BEuro₂₀₁₀ per year in R&D and innovation for the marine power industry could be cost-effective in the EU, if leading to cost reduction or efficiency improvements in the range explored.     

钢铁企业智能电网建设

降低配电网损耗、提高电能转换效率及提高资源综合利用率是钢铁企业节电重点,构建钢铁企业智能电网的根本目的是提高企业的电能利用率。钢铁企业智能配电网的关键技术有配电网节电技术、电能转换节电技术、需求侧发电技术、电能管理节电技术及智能电网管理信息技术等。     

海洋热能利用进展

海洋热能储量巨大,随时间变化相对稳定,具有广阔的开发利用前景。当前,海洋热能利用技术主要包括海洋温差能发电技术、海洋温差能制淡技术以及海水源热泵技术。发电技术要求海水温差不小于20℃,制淡技术要求海水温差不小于10℃,海水源热泵技术则在不同纬度地区、不同季节均能应用。本文重点分析了海洋温差能发电技术的3种循环方式,针对低温差导致低发电效率的问题,提出了利用太阳辐射加热温海水以提高温差和利用波浪能驱动泵以降低系统能耗两种提高发电效率的方法。     

Techno‐economic assessment for energy generation using bagasse: case study

Bagasse is selected as the biomass source that is studied because of its annual significant rate production in Iran and potential for energy generation. Bagasse has been as an energy source for the production of energy required to run the sugar factory. The energy needed by factories was supplied by burning bagasse directly inside furnaces, which had an exceptionally low output. To this end, today, a secondary use for this waste product is in combined heat and power plants where its use as a fuel source provides both heat and power. In addition, low efficiency of traditional methods was caused to increase the use of modern methods such as anaerobic digestion, gasification and pyrolysis for the production of bio‐fuels. In this paper, the energy conversion technologies are compared and ranked for the first time in Iran. Therefore, the most fundamental innovation of this research is the choice of the best energy conversion technology for the fuel production with a higher efficiency. To assess the feasibility application and economic benefit of biogas CHP plant, a design for a typical biogas unit is programmed. The results show the acceptable payback period; therefore, economically and technically, biogas CHP plant appears to be an attractive proposition in Iran. Copyright © 2012 John Wiley & Sons, Ltd.     

Optimal dispatch of multi energy system using power-to-gas technology considering flexible load on user side

The relation between power-to-gas technology (P2G) and energy interconnection becomes increasingly close. Meanwhile, the participation of flexible load on user side in system optimization has attracted much attention as an efficient approach to relieve the contradiction between energy supply and energy demand. Based on the concept of energy hub, according to its series characteristic, this paper established a generic multi-energy system model using the P2G technology. The characteristic of flexible load on user side was considered and optimal dispatch analysis was made, so as to reduce the cost, to reasonably dispatch the flexible load, to reduce the discharge, to enhance the new energy output, and to increase the power-to-gas conversion efficiency. Finally, a concrete analysis was made on the optimal dispatch result of the multi-energy system using the P2G technology considering flexible load on user side in the calculating example, and optimal dispatch of the system was verified via four different scenarios. The results indicate that cooperative dispatch of multi-energy system using the P2G technology considering flexible load on user side is the most economic, and can make a contribution to absorption of new energy and P2G conversion. In this way, environmental effects and safe and stable operation of the system can be guaranteed.     

A review on development of offshore wind energy conversion system

Wind energy conversion system, aiming to convert mechanical energy of air flow into electrical energy has been widely concerned in recent decades. According to the installation sites, the wind energy conversion system can be divided into land-based wind conversion system and offshore wind energy conversion (OWEC) system. Compared to land-based wind energy technology, although OWEC started later, it has attracted more attentions due to its significant advantages in sufficient wind energy, low wind shear, high power output and low land occupancy rate. In this paper, the principle of wind energy conversion and the development status of offshore wind power in the world are briefly introduced at first. And then, the advantages and disadvantages of several offshore wind energy device (OWED), such as horizontal axis OWED, vertical axis OWED and cross axis OWED are compared. Subsequently, several major constraints, such as complex marine environment, deep-sea power transmission and expensive cost of equipment installation faced by offshore wind conversion technology are presented and comprehensively analysed. Finally, based on the summary and analysis of some emerging technologies and the current situation of offshore wind energy utilization, the development trend of offshore wind power is envisioned. In the future, it is expected to witness multi-energy complementary, key component optimization and intelligent control strategy for smooth energy generation of offshore wind power systems.     

Hydrogen-based systems for integration of renewable energy in power systems: Achievements and perspectives

This paper is a critical review of selected real-world energy storage systems based on hydrogen, ranging from lab-scale systems to full-scale systems in continuous operation. 15 projects are presented with a critical overview of their concept and performance. A review of research related to power electronics, control systems and energy management strategies has been added to integrate the findings with outlooks usually described in separate literature. Results show that while hydrogen energy storage systems are technically feasible, they still require large cost reductions to become commercially attractive. A challenge that affects the cost per unit of energy is the low energy efficiency of some of the system components in real-world operating conditions. Due to losses in the conversion and storage processes, hydrogen energy storage systems lose anywhere between 60 and 85% of the incoming electricity with current technology. However, there are currently very few alternatives for long-term storage of electricity in power systems so the interest in hydrogen for this application remains high from both industry and academia. Additionally, it is expected that the share of intermittent renewable energy in power systems will increase in the coming decades. This could lead to technology development and cost reductions within hydrogen technology if this technology is needed to store excess renewable energy. Results from the reviewed projects indicate that the best solution from a technical viewpoint consists in hybrid systems where hydrogen is combined with short-term energy storage technologies like batteries and supercapacitors. In these hybrid systems the advantages with each storage technology can be fully exploited to maximize efficiency if the system is specifically tailored to the given situation. The disadvantage is that this will obviously increase the complexity and total cost of the energy system. Therefore, control systems and energy management strategies are important factors to achieve optimal results, both in terms of efficiency and cost. By considering the reviewed projects and evaluating operation modes and control systems, new hybrid energy systems could be tailored to fit each situation and to reduce energy losses.