中型生物质气化发电CDM项目案例分析

以广东省生物质气化发电技术应用为清洁发展机制(CDM)项目案例,基于3个基准线,应用增量成本分析方法,计算了中型生物质气化发电作为CDM项目的单位碳减排成本,并对其进行了敏感性分析。结果表明,CDM项目的单位碳减排成本在10-36美元/tCO2之间,且年处理生物质量为0.99-2.97万t时能实现年CO2减排量在1705-6038 tCO2/a之间。     

清洁发展机制(CDM)对促进生物质气化发电技术的作用分析

生物质气化发电产生的温室气体减排效果是十分明显的，但该技术的发电成本还高于常规能源发电，缺乏市场竞争力。该文分析了生物质气化发电系统的温室气体减排能力，探讨了执行清洁发展机制，交易CO2减排指标可以带给项目的额外经济收益以及对项目内部经济性的改善。分析表明，利用清洁发展机制可以对规模化发展生物质气化发电技术起到良好的促进作用。     

Energy and exergy performance of residential heating systems with separate mechanical ventilation

The paper brings new evidence on the impact of separate mechanical ventilation system on the annual energy and exergy performance of several design alternatives of residential heating systems, when they are designed for a house in Montreal. Mathematical models of residential heating, ventilation and domestic hot water (HVAC–DHW) systems, which are needed for this purpose, are developed and furthermore implemented in the Engineering Equation Solver (EES) environment. The Coefficient of Performance and the exergy efficiency are estimated as well as the entropy generation and exergy destruction of the overall system. The equivalent greenhouse gas emissions due to the on-site and off-site use of primary energy sources are also estimated. The addition of a mechanical ventilation system with heat recovery to any HVAC–DHW system discussed in the paper increases the energy efficiency; however, it decreases the exergy efficiency, which indicates a potential long-term damaging impact on the natural environment. Therefore, the use of a separate mechanical ventilation system in a house should be considered with caution, and recommended only when other means for controlling the indoor air quality cannot be applied.     

A Fuel Economy Study in Heavy Duty Diesel Engine Lubricants

Internal combustion engines′ fuel economy is an important role for engine designers,engine manufacturers over the past 30 years,especially passenger car motor oils.In heavy duty diesel engine,over the past 20 years,fuel economy has in some cases been sacrificed for exhaust gas emission optimizations.Now,Heavy Duty Automotive and the related industries have strong interest in fuel economy and the lubricants.It is driven by competitive market forces as well as government mandates and new emission regulations.Japan was the first country in the world to establish and implement heavy duty trucks and buses fuel economy standards.Other countries also have followed either by establishing direct fuel economy standards or greenhouse gas(GHG) emissions standards which are directly tied to fuel economy.This paper is discussing that heavy duty diesel engine lubricants can contribute on fuel economy.The contribution of various aspects of engine oil formulations on fuel economy will be discussed such as lubricant viscosity grade,lubricant additives and friction modifiers.In this paper,the evaluation discussions are based on fuel economy measurements in some bench tests,standardized laboratory engine tests and field tests.     

《京都议定书》动态评述

由于俄罗斯最终的批准,《京都议定书》将于2005年2月16日生效,标志着国际社会深化减缓气候变化行动的新时代的开始。但如何实施和实现《京都议定书》规定的减排目标,附件1缔约方面临不同的国情和挑战。其中欧盟的温室气体排放量在2008年至2012年间有望比1990年时的水平减少8.6％,完全有可能实现《京都议定书》目标。而日本和加拿大等国家将面临比较大的困难。《京都议定书》只是人类社会应对全球气候变化挑战的第一步。国际社会将不迟于2005年开始讨论2012年以后(即后京都)的气候政策问题。如何促使美国回到国际气候进程中来,以及促使发展中国家参与,将是谈判的重点。     

Assessing sustainable forest biomass potential and bioenergy implications for the northern Lake States region,USA

Forestlands in the United States have tremendous potential for providing feedstocks necessary to meet emerging renewable energy standards. The Lake States region is one area recognized for its high potential of supplying forest-derived biomass; however, the long-term availability of roundwood harvests and associated residues from this region has not been fully explored. Better distribution and temporal availability estimates are needed to formulate emerging state policies regarding renewable energy development. We used a novel predictive methodology to quantify sustainable biomass availability and likely harvest levels over a 100-year period in the Lake States region. USDA Forest Inventory and Analysis estimates of timberland were combined with published growth and yield models, and historic harvest data using the Forest Age Class Change Simulator (FACCS) to generate availability estimates. Monte-Carlo simulation was used to develop probability distributions of biomass harvests and to incorporate the uncertainty of future harvest levels. Our results indicate that 11.27–15.71 Mt y⁻¹ dry roundwood could be sustainably harvested from the Lake States. Assuming 65% collection rate, 1.87–2.62 Mt y⁻¹ residue could be removed, which if substituted for coal would generate 2.12–2.99 GW h of electricity on equivalent energy basis while reducing GHG (CO₂e) emission by 1.91–2.69 Mt annually. In addition to promoting energy security and reducing GHG emissions, forest residues for energy may create additional revenues and employment opportunities in a region historically dependent on forest-based industries.     

Long-term greenhouse gas emission reductions—what's possible,what's necessary?

Climate is changing (WMO, Press release No. 695, 2003) and there is increasing evidence that this is due to human activity (IPCC, Climate Change 2001—The Scientific Basis, Cambridge University Press, Cambridge, 2001). One way to react is to reduce greenhouse gas emissions into the atmosphere. Although this approach generally does not cause much objection, disagreements do occur when concrete emission targets are to be set. Against this background, the following article provides an arithmetic approach for the determination of long-term emission targets where the US and the EU are studied as examples.     

Floc-based sequential partial nitritation and anammox at full scale with contrasting N2O emissions

New Activated Sludge (NAS^®) is a hybrid, floc-based nitrogen removal process without carbon addition, based on the control of sludge retention times (SRT) and dissolved oxygen (DO) levels. The aim of this study was to examine the performance of a retrofitted four-stage NAS^® plant, including on-line measurements of greenhouse gas emissions (N₂O and CH₄). The plant treated anaerobically digested industrial wastewater, containing 264 mg N L⁻¹, 1154 mg chemical oxygen demand (COD) L⁻¹ and an inorganic carbon alkalinity of 34 meq L⁻¹. The batch-fed partial nitritation step received an overall nitrogen loading rate of 0.18-0.22 kg N m⁻³ d⁻¹, thereby oxidized nitrogen to nitrite (45-47%) and some nitrate (13-15%), but also to N₂O (5.1-6.6%). This was achieved at a SRT of 1.7 d and DO around 1.0 mg O₂ L⁻¹. Subsequently, anammox, denitrification and nitrification compartments were followed by a final settler, at an overall SRT of 46 d. None of the latter three reactors emitted N₂O. In the anammox step, 0.26 kg N m⁻³ d⁻¹ was removed, with an estimated contribution of 71% by the genus Kuenenia, which constituted 3.1% of the biomass. Overall, a nitrogen removal efficiency of 95% was obtained, yielding a dischargeable effluent. Retrofitting floc-based nitrification/denitrification with carbon addition to NAS^® allowed to save 40% of the operational wastewater treatment costs. Yet, a decrease of the N₂O emissions by about 50% is necessary in order to obtain a CO₂ neutral footprint. The impact of emitted CH₄ was 20 times lower.     

The GWP-Chart: An environmental tool for guiding urban planning processes. Application to concrete sidewalks

The systematized study of urban morphology has led to the development of integrated tools based on the knowledge of the relation between physical density and urban form. These tools do help planners and decision makers; however, environmental data is rarely included in them.This paper presents the GWP-Chart, a method that combines urban planning tools with environmental data, obtained through the use of the life cycle assessment (LCA) results. In order to explain its use, three urban fabrics have been selected. According to their morphology and their ground space index (GSI) and public space ratio (PSR) values, the contribution of the sidewalk subsystem to the global impact per square meter of urban development can be quantified and communicated.The GWP-Chart is applicable to all types of urban fabrics and scales (street or square, island, fabric or district), as well as adaptable to any urban infrastructure or subsystem and can be extended to other environmental impacts. Its advantages lie in its accurateness, adaptability and ease of interpretation.     

Influence of anaerobic digestion on the carbon footprint of various sewage sludge treatment options

This paper describes the results of a model set up to determine carbon footprints for sludge treatment solutions with and without standard or advanced anaerobic digestion. Complete and 'gate' (up to the point the sludge leaves the sewage works gate) footprints were calculated. The lowest carbon footprints corresponded with advanced digestion options, which reduced downstream energy and transport (hence carbon) requirements regardless of the endpoint of the sludge. The lowest complete carbon footprint solution coincided with advanced digestion, followed by drying with energy recovery. However, this option had the highest gate carbon footprint. In terms of gate carbon footprint, land application of an advanced digested sludge cake had the smallest footprint, followed by land application of dried pellets and finally incineration.