Self-ignition tendency of solid fuels: A gas emissions approach for early detection

Self-ignition of solid fuels storage is one of the main causes of human and economic losses. Additionally, each fire caused by this phenomenon emits an amount of toxic gases that contributes on the development of climate change. Nowadays, several methodologies are used in order to detect the self-ignition tendency of solid fuels, but they have as main disadvantages the amount of money and time that they require. The aim of this study is to propose a methodology of detection of incipient self-ignition of solid fuels through the measurement of gas emissions. This study compares existing methodologies to detect self-ignition tendency, such as TG, DSC or susceptibility, and to combustion related gas emission results. Different methods have been used to evaluate the results from the gas emission test, showing that interval and inflexion methods provide early detection of the self-heating process. With this methodology, it is possible to determine this process in advance with the equipment currently available in every industrial facility, reducing costs and improving efficiency.     

Modeling and simulation of biogas-fueled power system

The main objective of this paper is to develop a complete model that fully simulate a biogas-fueled power plant which can be used to supply a rural farm with sufficient electricity. The reactor is fed with animal manure of the farm. The proposed model consists of three main parts; a biogas reactor, a microturbine (MT) coupled to a permanent magnet synchronous generator, and a storage system. The model describes the dynamics of an MT and it is suitable for both steady state and transient simulation and analysis. The volume of biogas output delivered from the Anaerobic Digester depends on the reactor volume, reactor temperature, and animal manure type. The storage system is used to store the excess value of biogas if any. It is composed of two parts: a comparator and a storage tank. The comparator compares the volume of biogas produced by the reactor with that needed to supply the load. An adaptive controller is developed to withstand the system against any transient condition such as suddenly load increase/decrease. The proposed model is implemented for chemical and physical behaviors of the biogas production process, as well as for different variables of MT-generator operations. The model is implemented in Matlab/Simulink environment and tested under different operating conditions in both steady state and transient status to study the impacts of different variables on the system output. The output results prove its applicability and effectiveness under different operating conditions.     

水生植物生物能在苏州市CO2减排中的作用

苏州市的CO2排放量在逐年上升,CO2减排工作任务艰巨。开发无污染的新能源替代化石燃料是CO2减排的一种思路。苏州作为一个江南水乡城市,水资源丰富,水生植物生长旺盛。主要探讨了水生植物(包括藻类和水葫芦)生物能在苏州市CO2减排中的作用。通过粗略估算,藻类和水葫芦产生的年生物能(折算为标准煤)1 200.35万t,大约占苏州年总能耗的四分之一,即可以减少大约四分之一的CO2排放。因此,水生植物生物能在苏州市CO2减排中具有重要的作用。     

Production of boundary layer ozone from tropical American Savannah biomass burning emissions

Boundary layer ozone and carbon monoxide were measured at a savannah site in the Orinoco river basin, during the dry and wet seasons. CO and O₃ concentrations recorded around noontime show a good linear correlation, suggesting that the higher ozone levels observed during the dry season are photochemically produced during the oxidation of reactive hydrocarbons in the presence of NO_x both emitted by biomass burning. The rate of photochemical ozone production in the boundary layer ozone by biomass burning calculated from the production ratio ΔO₃/ΔCO (0.17±0.01 v : v) and the amount of CO produced by fires (0.26–1.3 mole m⁻² dry season⁻¹), ranges from 0.6 to 2.6 ppbv h⁻¹ for 8 h of daylight. This O₃ production rate is in fairly good agreement with the value derived from RO₂ radical measurements made in the Venezuelan savannah during the dry season. The net boundary layer production of O₃ from all tropical America savannah fires is estimated to range between 0.28 and 0.36 Tmol O₃ per year, which is about 3 times higher than the O₃ produced from pollution sources in the eastern United States during the summer. An extrapolation to all of the world's savannah would indicate a net boundary layer ozone production of about 1.2 Tmol yr⁻¹. This is discussed in the context of the overall global budget of tropospheric ozone.     

Interannual fluctuations in acoustic biomass estimates and in landings of small pelagic fish populations in relation to hydrology in the Strait of Sicily

The main results of research work carried out since 1998 with regard to the application of hydro-acoustic technologies for the evaluation of biomass and distribution of small pelagic fish species off the southern coast of Sicily are presented, taking into account information from hydrology and from ecology of the fish populations targeted. The biomass estimates and the population‐density charts presented concern the two main species, i.e. sardine Sardina pilchardus (Walbaum, 1792) and anchovy Engraulis encrasicolus (Linnaeus, 1758). Both the sardine and anchovy populations experienced large inter-annual fluctuations, with biomass estimates ranging from 6000 to over 36,000 tonnes (t) (sardine) and from about 7000 to 23,000 t (anchovy). Acoustic estimates are largely consistent with landings recorded in Sciacca (the main fishing port for small pelagic species in the study area) during the year following the evaluation surveys. In addition, trends in sardine and anchovy biomass estimates appears to be negatively correlated with the mean sea surface temperature calculated over the time intervals January–September (sardine) and June–November (anchovy) of the preceding year, which correspond to larval and juvenile growth periods of target species. Observed patterns would suggest the importance of enrichment processes relevant to the survival of early stages, so determining recruitment success and finally higher population sizes.     

提高碳汇潜力：量化树种和造林模式对碳储量的影响

全球气候变化背景下,造林再造林固定的碳可以抵消温室气体减限排量。通过造林再造林增加森林面积可以增加林业碳汇,在土地面积有限的情况下,提高造林质量——在有限的造林面积上固定更多的碳是十分必要的。树种和造林模式的选择是增加森林生态系统碳汇的重要管理决策。文章综述了树种和造林模式对生态系统的碳储量的影响。树种从生物量的积累,凋落物和土壤碳储存,以及木材密度、碳贮存量等几个方面探讨其对生态系统碳库的影响。混交林能充分利用立地条件、改善树木营养状况,并且可以减少病虫害和森林火灾。同时分析了我国在森林经营方面存在的问题和改善途径,以期为该领域的研究提供参考。     

Biorefinery study of availability of agriculture residues and wastes for integrated biorefineries in Brazil

Brazil has a great potential for use renewable raw materials in biorefineries. It is one of the largest producers of agricultural and animal commodities, which produce large amounts of residues and wastes. These agricultural residues and animal waste can be effectively transformed to energy and other products in systems similar to a ethanol refinery where an integrated process involves conversion for biomass into fuel, energy and chemicals, integrated in the context of a biorefinery. The objective of this work is the determination of the actual availability of main agricultural residues and animal wastes generated in Brazil and of their generation potential index and their prospects for 2020. The results indicate that the sugarcane has the highest agronomic availability, reaching 157 million tons of fresh material and an estimated reuse potential of 19.6 million tons (dry basis), followed by soybeans, rice, maize, orange, wheat, cotton, cassava and tobacco.     

Biomass Based Sorption Cooling Systems for Cold Storage Applications

Controlled atmospheric storage is a widely popular technique for storage of fruits and vegetables. In this paper, the experimental studies on biomass powered absorption systems for cold storage applications using ammonia water as a working fluid pair is presented. The heat input to the absorption system is supplied by a producer gas obtained from a downdraft gasifier, using firewood as fuel. The system is designed and fabricated to store about 15 MT of fruits and vegetables, having a cooling capacity of 3 TR. The effect of sink temperature, solution flow rate, cooling water flow rate and biomass consumption on the performance of the system has been analyzed. It is found that the real co-efficient of performance of the system is around 0.35 - 0.2, considering the source-site factor for auxiliary power consumption. The operating Cost/h for the biomass based cold storage system is lower than the presently available conventional compression based units.     

生物质材料在重金属废水处理中的应用

可再生、低成本、有效且易从环境获取的生物质材料越来越多地用于去除废水中的重金属离子。本文着重介绍三大类生物质材料：Ⅰ、动物类（主要是甲壳素和壳聚糖衍生物）;Ⅱ、植物类（包括木质素、活性炭、竹炭、富含单宁的物质、农林废弃物等）;Ⅲ、微生物类（各种茵类等）,及其改性产物在处理有毒重金属废水方面的应用研究进展。     

Recovery of biomass wastes by hydrolysis in sub-critical water

The recovery of waste substances is important not only for the prevention of environmental issues, but also for the rational utilization of natural resources. Hydrolysis reaction in sub-critical water is a promising method for the treatment of organic wastes and has been attracting worldwide attention. In this paper, sub-critical water hydrolysis was employed as a method for producing amino acids, reducing sugars, bio-oil and gas fuels from biomass wastes. The current statuses of these useful chemicals production from biomass wastes by hydrolysis in sub-critical water were reviewed. The review indicates that sub-critical water hydrolysis can be an efficient process for recovering useful chemicals from biomass wastes. This method is renewable, sustainable, efficient, and safe for the environment.