Life improvement programme of producer gas–biodiesel operated dual fuel engines

Biomass fuels have attracted an increase in interest due to the alarming rise in global greenhouse gases and the rapid rise of petroleum prices. Energy security on a sustainable basis can come only with the responsible use of home-sourced resources and not from imported fossil fuels such as coal or crude petroleum products. Partial combustion of biomass in the downdraft gasifier generates producer gas that can be used as the sole fuel or as a supplementary fuel for internal combustion engines. A dual fuel mode of operation, in which producer gas is used as a supplementary inducted fuel along with injected pilot fuels of Honge or Jatropha biodiesels, can be a promising alternative to diesel only usage. Two different carburettors were designed and fabricated to facilitate gas entry at 45° and 90° to the engine cylinder. The engine was experimentally optimised using Honge or Jatropha biodiesels–producer gas combinations with respect to maximum pilot fuel savings in the dual fuel mode operation, optimum air and gas mixing with different tested carburettors. The performance, combustion and emission characteristics of these dual fuel combinations were compared at different load conditions. The results showed that biodiesels of Honge or Jatropha oils–Producer gas combinations with carburettor of 90° gas entry resulted in better performance.     

Effect of mixing chamber venturi,injection timing,compression ratio and EGR on the performance of dual-fuel engine operated with HOME and CNG

Stringent environmental policies and the ever increasing demand for energy have triggered interest in novel combustion technologies that use alternative fuels as energy sources. Of these, pilot-ignited compressed natural gas (CNG) engines that employ small biodiesel pilot to ignite a premixed natural gas–air mixture have received considerable attention. This paper discusses the effect of mixing chamber venturi, injection timing, compression ratio and exhaust gas recirculation (EGR) on the performance of dual-fuel engine operated on biodiesel derived from honge oil and is called honge oil methyl ester (HOME) and CNG. The proposed study mainly focuses on the manifold induction of CNG along with HOME injection. However, CNG can also be injected using port or direct gas injector (Lakshmanan and Nagarajan 2010, Energy 35, pp. 3172–3178). The future study will involve these methods of CNG injection. From this study, it is concluded that an advanced injection timing and an increased compression ratio resulted in increased brake thermal efficiency and reduced smoke, hydrocarbons and carbon monoxide emissions. However, nitrogen oxides (NO _x ) emission increased significantly. The increased NO _x emission was effectively reduced with EGR method. A mixing chamber venturi of 3 mm size, injection timing of 27° before top dead centre (BTDC), compression ratio of 17.5 and 10% EGR were found to be optimum for the modified compression ignition engine that was operated on CNG–HOME dual-fuel mode.     

Development of Indicators to Assess Economic Vulnerabilities to Changes in Ecosystem Services: Case Study of Counties in Maryland,USA

We develop indicators showing the relative environmental burdens that human activities place on locales for a given level of economic benefits. The main purpose is to develop tools that allow us to examine the potential vulnerabilities within economies to changes in resource conditions. The indicators of pollution emission or resource consumption per job can be used to identify potential challenges to resource and industry managers and to compare areas in terms of their ability to adapt to change. For example, if a large number of area jobs are dependent on abundant water, this indicates a vulnerability to a reduction in water availability for industrial use. We develop a case study for 23 counties and 1 city in Maryland to examine the usefulness and limitations of the indicators. Our case study demonstrates that the indicators provide an informative view into patterns of local economic activity and use of an area’s environmental goods and services. In contrast to patterns for total environmental burdens (e.g., total SO₂ emissions) that are typically reported, the rates of environmental burden per job are not simply correlated with high or low economic output. Thus, the indicators represent distinct patterns of environmental burdens per job that reflect reliance on environmental services. The indicators have some limitations when used at this fine scale because they can misrepresent conditions in counties in which economic sectors are dominated by one or a few businesses. For this reason, the indicators are best used as a regional screening tool.     

Greenhouse gas emission reductions in the post-Kyoto period: Emission intensity changes required under the 'contraction and convergence' approach

Various approaches have been proposed for allocating commitments to countries regarding the mitigation of greenhouse gas emissions. One of these methods is the ‘contraction and convergence’ approach, which defines emission permits on the basis of converging per capita emissions under a contracting global emission profile. The approach is unique in its simplicity. Only two major issues need to be negotiated and agreed upon: the target atmospheric concentration of CO₂ and the date when the entitlements are to converge at equal per capita allocations. According to the contraction and convergence approach, developing countries can continue their current emission trends, whereas industrialized countries should reduce their emissions quite dramatically. This regime represents a shift away from the current approach towards defining commitments for all parties and their evolution over the long term. This article analyses how allocation schemes determined by the contraction and convergence approach might affect certain OECD and non‐OECD countries. Results for eleven countries selected for analysis (United States, United Kingdom, Germany, France, Japan, China, Venezuela, Thailand, Brazil, India and Indonesia) reveal that trends observed in the past few decades in most industrialized countries will lead to the contraction and convergence target.     

Nutrient-Balance Modeling as a Tool for Environmental Management in Aquaculture: The Case of Trout Farming in France

The control and prevention of nutrient pollution from fish farming plays an essential role in the French regulatory framework. Assessing nutrient emissions from fish farms is important in terms of farm authorization, taxation, and monitoring. Currently employed strategies involve both water sampling and empirical modeling. This article reports the work and outcomes of an expert panel that evaluated existing methodologies and their possible alternatives. The development and evaluation of a nutrient-balance approach was assessed as a potential alternative to currently used methodologies. A previously described nutrient-balance model was suggested and parameterized using expert choice, and its validity and applicability were assessed. The results stress that the nutrient-balance model provides more robust and relatively conservative waste estimates compared to the currently used methodologies. Sensitivity of the approach to the uneven data quality available at farm level, difficulties of on-farm measurements, as well as model requirements and limitations are discussed.     

Can China control the side effects of motor vehicle growth?

Motor vehicle growth in China is the fastest in the world. This is placing great strain on the urban environment and causing a rapid increase in oil imports and motor vehicle carbon dioxide emissions. To deal with the environmental and health effects of air pollution, China has adopted a strong motor vehicle pollution control programme and imposed limits on fuel consumption of new light duty vehicles. The article will review these problems and programmes. Special focus will be given to the need to reduce sulphur levels in both gasoline and diesel fuel.     

Processing National CO2 Inventory Emissions Data and their Total Uncertainty Estimates

The uncertainty of reported greenhouse gases emission inventories obtained by the aggregation of partial emissions from all sources and estimated to date for several countries is very high in comparison with the countries’ emissions limitation and reduction commitments under the Kyoto Protocol. Independent calculation of the estimates could confirm or question the undertainty estimates values obtained thus far. One of the aims of this paper is to propose statistical signal processing methods to enable calculation of the inventory variances. The annual reported emissions are used and temporal smoothness of the emissions curve is assumed. The methods considered are: a spline-function-smoothing procedure; a time-varying parameter model; and the geometric Brownian motion model. These are validated on historical observations of the CO₂ emissions from fossil fuel combustion. The estimates of variances obtained are in a similar range to those obtained from national inventories using TIER1 or TIER2. Additionally, some regularities in the observed curves were noticed.     

1991～2000年中国森林火灾直接释放碳量估算

目前的研究表明生物圈的燃烧产物对大气有短期和长期的影响,植被燃烧会直接排放对环境有显著影响的气体,包括CO2和CH4等影响全球变化的温室气体,燃烧产生的固体颗粒物也会引起空气污染和影响天气。该文根据1991－2000的森林火灾统计数据和生物量研究结果,计算出我国森林火灾年均消耗森林地上生物量5Tg-7Tg,直接排放碳20.24Tg-28.56Tg,释放CO2和CH4分别为74.2Tg-104.7Tg和1.797Tg-2.536Tg,排放烟雾颗粒物0.999Tg-1.410Tg。1991－2000年森林火灾每年平均排放CO2量占我国总排放量（按2000年计算）的2.7-3.9%,CH4排放量占总排放量的3.3-4.7%。     

Towards global climate change mitigation: assessment of an afforestation option for Nigeria

This paper assesses the potential of an intensive afforestation program as a measure of reducing the atmospheric concentration of carbon in Nigeria. The results presented are based on the recently completed Nigerian Country Studies Program on Climate Change Mitigation. A comprehensive mitigation analysis process (COMAP) model was employed to carry out detailed cost/benefit evaluation of the mitigation option. The end-use based scenario adopted was considered the most appropriate strategy to sustainably implement the mitigation option in Nigeria.The analyses showed that the country could significantly reduce net carbon emission while at the same time meet all her essential domestic wood needs, if approximately 7.5×10⁶ ha of wasteland could be committed to an afforestation program over the 40 year period of projection. The initial cost of establishing such forest plantations, taking cognisance of the opportunity cost of land averaged at about US$500/ha, or in carbon terms, a unit cost of about $13 per tonne of carbon. In terms of carbon flow, if all the end-product based plantations considered (i.e. fuelwood, poles, pulpwood, sawlogs and veneer) were fully established and maintained, it was estimated that by the year 2030, the total carbon stored in the afforested land would be about 638.0×10⁶ t of carbon with an annual incremental rate of 16.0×10⁶ t of carbon. Other economic indicators (i.e. net present value of benefits, present value of costs and benefit for reduced atmospheric carbon) when evaluated showed that the afforestation option could be economically viable even when the investment capital was discounted at rates ranging from 9 to 33 percent for different wood products. It should be noted, however that implementation of such a program would require huge sums of money and a high degree of commitment on the part of Federal, State and Local governments if the associated financial, social and environmental benefits were to be derived.     

The Appalachian Mountains' Copper Basin and the concept of environmental susceptibility

The Copper Basin is located within the southern Appalachian Mountains primarily in extreme southeastern Tennessee, USA. It has long been known for its copper mining/smelting and associated chemical industry, as well as its severely injured environment. Virtually all previous commentary on the environmental degradation at this location have focused on human activities and their destructive impact. This article approaches the subject from a different angle, one that emphasizes the interaction between man and nature. The site's physical setting, industrial history, and environmental history are briefly reviewed. The theory then presented here is that certain of the Copper Basin's natural features made its environment unusually vulnerable to the negative impact of copper mining and smelting, especially as practiced around the turn of the century. These features are identified. This reasoning provides the basis for the concept of environmental susceptibility, which is defined and discussed. A few of its applications are mentioned. This study offers a new perspective on the Copper Basin, as well as insights for those whose work involves investigating the man/nature relationship—both past and present.