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1.
Energy and carbon balances of wood cascade chains   总被引:1,自引:0,他引:1  
In this study we analyze the energy and carbon balances of various cascade chains for recovered wood lumber. Post-recovery options include reuse as lumber, reprocessing as particleboard, pulping to form paper products, and burning for energy recovery. We compare energy and carbon balances of chains of cascaded products to the balances of products obtained from virgin wood fiber or from non-wood material. We describe and quantify several mechanisms through which cascading can affect the energy and carbon balances: direct cascade effects due to different properties and logistics of virgin and recovered materials, substitution effects due to the reduced demand for non-wood materials when wood is cascaded, and land use effects due to alternative possible land uses when less timber harvest is needed because of wood cascading. In some analyses we assume the forest is a limiting resource, and in others we include a fixed amount of forest land from which biomass can be harvested for use as material or biofuel. Energy and carbon balances take into account manufacturing processes, recovery and transportation energy, material recovery losses, and forest processes. We find that land use effects have the greatest impact on energy and carbon balances, followed by substitution effects, while direct cascade effects are relatively minor.  相似文献   

2.
This paper presents results from a gate-to-gate analysis of the energy balance, greenhouse gas (GHG) emissions and economic efficiency of biochar production from palm oil empty fruit bunches (EFB). The analysis is based on data obtained from EFB combustion in a slow pyrolysis plant in Selangor, Malaysia. The outputs of the slow pyrolysis plant are biochar, syngas, bio-oil and water vapor. The net energy yield of the biochar produced in the Selangor plant is 11.47 MJ kg−1 EFB. The energy content of the biochar produced is higher than the energy required for producing the biochar, i.e. the energy balance of biochar production is positive. The combustion of EFB using diesel fuel has the largest energy demand of 2.31 MJ kg−1 EFB in the pyrolysis process. Comparatively smaller amounts of energy are required as electricity (0.39 MJ kg−1 EFB) and for transportation of biochar to the warehouse and the field (0.13 MJ kg−1 EFB). The net greenhouse gas emissions of the studied biochar production account for 0.046 kg CO2-equiv. kg−1 EFB yr−1 without considering fertilizer substitution effects and carbon accumulation from biochar in the soil. The studied biochar production is profitable where biochar can be sold for at least 533 US-$ t−1. Potential measures for improvement are discussed, including higher productivity of biochar production, reduced energy consumption and efficient use of the byproducts from the slow pyrolysis.  相似文献   

3.
This article presents the evaluation of a pilot project where four decision-making tools were applied in a municipal energy-planning process in a Swedish municipality. The tested tools were citizens' panel, a scenario method, life cycle assessment and qualitative checklists for environmental assessment (EA). The results presented are based on two focus group discussions with the participants from the project: one with the municipal workgroup and one with the researchers that were responsible for the application of the decision-making tools. The results show that energy planning is a process of learning and dialogue, and workshop methodology was found to be favourable for open dialogue. This test also shows that public involvement can contribute to a valuable dialogue in the visionary work and suggestions of actions and strategies. Another conclusion is that energy planning needs to be iterative, even in the scoping. This test also shows that there is a need to develop simplified tools that include EA and a broad systems approach in local energy planning.  相似文献   

4.

Alternative energy balances aimed to mitigate greenhouse gas (GHG) emissions are developed as alternatives to the baseline energy balance. The section of mitigation options is based on the results of the GHG emission inventory for the 1987–1992 period. The energy sector is the main contributor to the total CO2 emissions of Bulgaria. Stationary combustion for heat and electricity production as well as direct end-use combustion amounts to 80% of the total emissions. The parts of the energy network that could have the biggest influence on GHG emission reduction are identified. The potential effects of the following mitigation measures are discussed: rehabilitation of the combustion facilities currently in operation; repowering to natural gas; reduction of losses in thermal and electrical transmission and distribution networks; penetration of new combustion technologies; tariff structure improvement; renewable sources for electricity and heat production; wasteheat utilization; and supply of households with natural gas to substitute for electricity in space heating and cooking. The total available and the achievable potentials are estimated and the implementation barriers are discussed.

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5.
The combination of synthetic thermoplastic polymers and wood is normally problematic because wood surfaces are hydrophilic while typical thermoplastic polymers are hydrophobic. A possible solution is to use block copolymer coupling agents. In this work we show the use of a potentially useful synthetic method of producing hydrophilic-hydrophobic block copolymers as hydrophobic coatings and coupling agents in polystyrene/wood flour composites. In particular, wood veneers are coated with water-based emulsions of hydrophilic-hydrophobic block copolymers from styrene and methacrylic acid. Dried coated surfaces are shown to become hydrophobic through dynamic contact angle measurements. When wood flour is coated with the hydrophilic-hydrophobic block copolymer based on styrene and acrylic acid, significant improvement in the ultimate tensile properties of composites formed from coated wood flour/polystyrene mixtures is realized. Since no volatile organic compounds (VOCs) are used in coating wood surfaces and subsequent composite production, improvement in mechanical properties of thermoplastic/wood flour composites are shown to occur in environmentally responsible formulations.  相似文献   

6.
Carbon and N losses reduce the agronomic value of compost and contribute to greenhouse gas (GHG) emissions. This study investigated GHG emissions during composting of straw-bedded manure (SBM) and wood chip-bedded manure (WBM). For SBM, dry matter (DM) loss was 301 kg Mg(-1), total carbon (TC) loss was 174 kg Mg(-1), and total nitrogen (TN) loss was 8.3 kg Mg(-1). These correspond to 30.1% of initial DM, 52.8% of initial TC, and 41.6% of initial TN. For WBM, DM loss was 268 kg Mg(-1), TC loss was 154 kg Mg(-1), and TN loss was 1.40 kg Mg(-1), corresponding to 26.5, 34.5, and 11.8% of initial amounts. Most C was lost as CO2 with CH4 accounting for <6%. However, the net contribution to greenhouse gas emissions was greater for CH4 since it is 21 times more effective at trapping heat than CO2. Nitrous oxide (N2O) emissions were 0.077 kg N Mg(-1) for SBM and 0.084 kg N Mg(-1) for WBM, accounting for 1 to 6% of total N loss. Total GHG emissions as CO2-C equivalent were not significantly different between SBM (368.4 +/- 18.5 kg Mg(-1)) and WBM (349.2 +/- 24.3 kg Mg(-1)). However, emission of 368.4 kg C Mg(-1) (CO2-C equivalent) was greater than the initial TC content (330.5 kg Mg(-1)) of SBM, raising the question of the net benefits of composting on C sequestration. Further study is needed to evaluate the impact of composting on overall GHG emissions and C sequestration and to fully investigate livestock manure management options.  相似文献   

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In the Netherlands various fields of policy planning and decision making are related to the environment, of which physical land use planning and environmental planning are the most important. In the last 20 years the environmental effects of production, mobility and consumption in this densely populated country have increased. The location and land use of economic activities have therefore become a main concern for environmental policy which has as its aim the improvement and conservation of the quality of the natural and human environment. The prospects for a better co‐ordination and integration of the two policy ‘tracks’ have become a matter of political, scientific and public concern. In some regions the government has started experiments with more integrated environmental policy and management. This paper discusses some of the possibilities and limitations of this regionally oriented policy against the background of a more effective environmental policy, especially in two cases—a rural area in the province of Gelderland and the region of Schiphol Airport.  相似文献   

9.
This article examines the potential contribution of analytical philosophy to planning theory. In contrast to some recent discussions it takes as its starting point town planning as actually practised, and recognises the ideological framework within which, for the most part, twentieth century analytical philosophy has been conducted. It concludes that knowledge of philosophy may be of some limited use to the planning theorist.  相似文献   

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Abstract

The design aspects of energy selection and energy efficiency are described. These topics are key components of Design for Environment, and thus are important considerations in industrial ecology. In the article, background material is presented on energy forms, sources, carriers and conversion technologies. Then, energy use in countries, regions and sectors is discussed, and the impact of energy use on the environment described. Efficiencies and other measures of merit for energy use are presented, and design for energy selection and for energy efficiency are described, highlighting energy-related design factors for pollution prevention. Finally sustainable development and its relation to energy and efficiency are discussed, and a case study is presented.  相似文献   

13.
This article presents a research project on mobility management in Danish municipalities aimed at creating more sustainable mobilities. The project, called Formula M (2011–2014), worked within sciences, public and private sectors, and civil society. Often contemporary projects in both planning and designing sustainable mobilities fall short when it comes to changing praxis to limit CO2 emissions, where they just concentrate on technocratic elements. They often neglect the ‘why’ and ‘for what’ which is needed in order to drive such change. In the Formula M project, focus has been on supporting the planners involved in the project on their ‘why’ and ‘for what’. Based on a theoretical understanding of relational and collaborative planning the article contributes to an understanding of which approaches and methods can be used to facilitate the relationships and dialogues between many actors. Methodologically, this has been sought through a specific focus on the role of utopias as a tool for storytelling.  相似文献   

14.
《The Environmentalist》1981,1(3):246-246
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15.
Disposal of discarded chromated copper arsenate (CCA)-treated wood in landfills raises concerns with respect to leaching of preservative compounds. When unweathered CCA-treated wood is leached using the toxicity characteristic leaching procedure (TCLP), arsenic concentrations exceed the toxicity characteristic (TC) limit of 5mg/L in most cases. The majority of discarded CCA-treated wood, however, results from demolition activities, where the wood has typically been subjected to weathering. Since preservatives do migrate from the wood during its normal use, leaching characteristics of weathered and aged CCA-treated wood may differ from unweathered wood. To evaluate this, CCA-treated wood removed from service after various degrees of weathering was collected from multiple sources and leached with the TCLP, the synthetic precipitation leaching procedure (SPLP) and California's waste extraction test (WET). Five to seven individual pieces of wood were analyzed from each source. The average TCLP arsenic concentration for the 14 sources ranged from 3.2 to 13 mg/L. The average TCLP concentrations of the 100 wood pieces tested were 6.4, 5.9 and 3.2 mg/L for arsenic, copper and chromium, respectively. Overall, in 60 out of 100 samples tested by the TCLP, arsenic concentrations exceeded 5 mg/L (the TC regulatory value). SPLP leachate concentrations were similar to TCLP concentrations, although copper leached somewhat more with the TCLP. WET leachate concentrations were approximately a factor of 10 higher than TCLP concentrations. Discarded CCA-treated wood, even after exposure to years of weathering, often exceeds the TC limit for arsenic and without the current regulatory exemption would possibly require management as a TC hazardous waste in the US.  相似文献   

16.
The resurgence in the use of wood in the United States for residential heating has been accompanied by a dramatic increase in deaths and injuries from residential fires. Toxic materials present in woodsmoke also appear to present a significant public health hazard. As a result of these factors, production of residential wood heat can be up to two orders of magnitude more hazardous than generation of an equivalent amount of electric energy at a coal-fired power plant. Proper care in installation and operation of wood stoves, as well as technological innovations that control wood-stove emissions, can greatly reduce the health and safety hazards of residential heating with wood.  相似文献   

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18.
The coastal tourist areas of Spain have seen open conflict between planners and the public over the flood of tourist developments. The Costa Brava in the region of Catalonia is chosen for the purpose of this study which looks at the effects of the Land Use law of 1976 requiring all municipalities to prepare General Plans. The failure of plans which attempted to severely restrict tourist growth, and this paper's conclusions, that the expansion of tourist pressure into new areas may create new conditions, suggest a regional approach to policy.  相似文献   

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The country estate has a particular place in the English countryside and its contribution to the landscape scene is distinct and valuable. The paper describes an approach to planning a large country estate of parkland, woodland and estate villages in Cheshire. A Reconnaissance Survey led to the Outline Strategy for six ‘landscape types’ discovered on the estate. The Landscape Conservation Plan is described and the crucial importance of conservation measures is emphasised.  相似文献   

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