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1.
The greenhouse gases (GHG) emissions from land-use change are of particular concern for land-based biofuels. Emissions avoided by substituting fossil fuels with biofuels may be offset by emissions from direct and indirect land-use changes (LUC). There is an urgent need to investigate what impact land-use change emissions may have on the expansion of bioenergy and biofuels, in the context of EU mitigation policies. This paper focuses on Ireland, which faces a number of challenges in delivering its renewable energy and GHG reduction targets. The Irish TIMES energy systems model was used to assess the impact of a range of land-use change emissions’ levels on the evolution of Ireland’s low-carbon energy system. A reference scenario was developed where LUC is ignored and Ireland achieves a least-cost low-carbon energy system by 2050. If high indirect land-use change (ILUC) emissions are included, this results in a decrease by 30 % in bioenergy and a 68 % increase in marginal abatement costs by 2050. Hydrogen is used instead of bioenergy in the freight sector in this scenario, while private cars are fuelled by renewable electricity. If GHG emissions from ILUC were considered less severe, indigenous grass biomethane becomes the key biofuel representing 31 % of total bioenergy consumption. This is in line with recent research in Ireland of the key role that grass biomethane can play.  相似文献   

2.
In Taiwan, due to the limited capacity of waste cooking oil, palm oil has been viewed as the potential low-cost imported feedstock for producing biodiesel, in the way of obtaining oil feedstock in Malaysia and producing biodiesel in Taiwan. This study aims to evaluate the cradle-to-grave life cycle environmental performance of palm biodiesel within two different Asian countries, Malaysia and Taiwan. The phases of the life cycle such as direct land-use-change impact, plantation and milling are investigated based on the Malaysia case and those of refining, and fuel production as well as engine combustion is based on Taiwan case. The greenhouse gas (GHG) emission and energy consumption for the whole life cycle were calculated as ?28.29 kg CO2-equiv. and +23.71 MJ/kg of palm-derived biodiesel. We also analyze the impacts of global warming potential (GWP) and the payback time for recovering the GHG emissions when producing and using biodiesel. Various scenarios include (1) clearing rainforest or peat-forest; (2) treating or discharging palm-oil-milling effluent (POME) are further developed to examine the effectiveness of improving the environmental impacts  相似文献   

3.
Biofuels are considered as eco-friendly fuels and can readily replace fossil fuels while helping to reduce greenhouse gas emissions and promoting sustainable rural development. Although Algeria is an oil producer and exporter, the development of renewable energies is a strategic goal for public authorities, which are giving new impetus to this sector to replace the fossil energy resources of which are becoming increasingly scarce. In this context, the life-cycle assessment (LCA) of a second-generation biodiesel derived from Ricinus communis feedstock is undertaken. LCA is a tool that can be used effectively in evaluating various renewable energy sources for their sustainability and can help policy makers to choose the optimal energy source for specific purpose. The life cycle of Castor bean-based biodiesel production includes the stages of cultivation, oil extraction, and biodiesel production. The impact categories studied were global warming, Energy return-on-energy investment (EROEI), human health, and ecosystem. We have used the impact 2002 + evaluation method which is implemented in the SimaPro© software package. Moreover, it is the most useful method for identifying and measuring the impact of industrial products on the environment. Results show that among all the production stages, the cultivation process of Ricinus communis and the conversion of oil to biodiesel are the largest contributors to most of environmental impact categories. Life-cycle analysis revealed that the use of castor for biodiesel production could have many advantages like an energy return-on-energy investment (EROEI) of 2.60 and a positive contribution to climate-change reduction as revealed by a positive carbon balance.  相似文献   

4.
The European Union recognizes the priority of new bio-based industrial pathways, such as bio-based succinic acid (bio-SA). This study has investigated, through a life cycle method, the cradle-to-factory gate greenhouse gas (GHG) emissions and non-renewable energy use (NREU) of bio-SA from lignocellulosic giant reed (GR) feedstock grown on marginal lands in Southern Italy (GR bio-SA). The aims were to: (1) evaluate the environmental performance of the GR bio-SA and (2) discuss the GR bio-SA profile with respect to its fossil counterparts and alternative bio-SA routes. For 1 kg of GR bio-SA, the gross GHG emissions amounted to 3.9 kg CO2 eq, while through the inclusion of the biogenic C potentially stored in SA molecule (1.47 kg CO2 eq) and soil organic matter (0.44 kg CO2 eq), the final net global warming potential would be nearly halved. Similarly to current starch-based SA supply chains, the GR bio-SA showed: (1) better gross GHG profile compared to the fossil adipic acid (GHG emissions reduced by 55%) and (2) comparable net GHG emissions in comparison with petrochemicals SA and maleic acid. The total NREU for 1 kg of GR bio-SA amounted to 26.6 MJ, with reduced energy consumption by about 55–79% relative to fossil counterparts, thanks to the on-site energetic valorization of lignin and holocellulose residues with relatively high heating values. The soy protein concentrate and the inorganic chemicals used in the co-fermentation showed up the prevailing contributions to the GHG and NREU profiles of the GR bio-SA, suggesting the need to optimize nitrogen and carbon sources of the growth medium.  相似文献   

5.
Among various clean energy technologies, one innovative option for reducing the emission of greenhouse gases (GHGs) and criteria pollutants involves pairing carbon capture and storage (CCS) with the production of synthetic fuels and electricity from a combination of coal and sustainably sourced biomass. With a relatively pure CO2 stream as an inherent byproduct of the process, most of the resulting GHG emissions can be eliminated by simply compressing the CO2 for pipeline transport. Subsequent storage of the CO2 output in underground reservoirs can result in very low—perhaps even near-zero—net GHG emissions, depending on the fraction of biomass as input and its CO2 signature. To examine the potential market penetration and environmental impact of coal-and-biomass-to-liquids-and-electricity (CBtLE), a system-wide sensitivity analysis was performed using the MARKet ALlocation energy model. CBtLE was found to be most competitive in scenarios with a combination of high oil prices, low CCS costs, and, unexpectedly, non-stringent carbon policies. In the scheme considered here (30 % biomass input on an energy basis and 85 % carbon capture), CBtLE fails to achieve significant market share in deep decarbonization scenarios, regardless of oil prices and CCS costs. Such facilities would likely require higher fractions of biomass feedstock and captured CO2 to successfully compete in a carbon-constrained energy system.  相似文献   

6.
Biodiesel derived from algae is considered as a sustainable fuel, but proper downstream processing is necessary to minimize the environmental footprint of this process. Algae is grown in dilute liquid cultures, and achieving the low water contents required for extraction represents one of the greatest challenges for the production of algae derived biodiesel. An analysis of the life cycle emissions associated with harvesting, dewatering, extraction, reaction, and product purification stages for algae biodiesel were performed. This “base case” found 10,500 kg of total emissions per t of biodiesel with 96 % of those attributed to the spray dryer used for dewatering. Alternative cases were evaluated for various sequences of mechanical and thermal dewatering techniques. The best case, consisted of a disk-stack centrifuge, followed by the chamber filter press, and a heat integrated dryer. This resulted in 875 kg emissions/t of biodiesel, a 91 % reduction from the base case. Significant reductions in life cycle emissions were achieved for all mechanical dewatering alternatives compared to the base case, but further improvements using these existing technologies were limited. Additional improvements will require the development of new techniques for water removal or wet extractions.  相似文献   

7.
With the increasing attention to the environmental impact of discharging greenhouses gases, there has been a growing public pressure to reduce the carbon footprint associated with the use of fossil fuels. In this context, one of the key strategies is the substitution of fossil fuels with biofuels such as biodiesel. The design of biodiesel production facilities has traditionally been carried out based on technical and economic criteria. Greenhouse gas (GHG) policies (e.g., carbon tax, subsidy) have the potential to significantly alter the design of these facilities, the selection of the feedstocks, and the scheduling of multiple feedstocks. The objective of this article is to develop a systematic approach to the design and scheduling of biodiesel production processes while accounting for the effect of GHG policies in addition to the technical, economic, and environmental aspects. An optimization formulation is developed to maximize the profit of the process subject to flowsheet synthesis and performance modeling equations. Furthermore, the carbon footprint is accounted for with the help of a life cycle analysis (LCA). The objective function includes a term which reflects the impact of the LCA of a feedstock and its processing to biodiesel. A multiperiod approach is used to discretize the decision-making horizon into time periods. During each period, decisions are made on the type and flowrate of the feedstocks, as well as the associated design and operating variables. A case study is solved with several scenarios of feedstocks and GHG policies.  相似文献   

8.
Fruit processing industries generate tremendous amount of solid wastes which is almost 35-40% dry weight of the total produce used for the manufacturing of juices. These solid wastes, referred to as, “pomace” contain high moisture content (70-75%) and biodegradable organic load (high BOD and COD values) so that their management is an important issue. During the management of these pomace wastes by different strategies comprising incineration, landfill, composting, solid-state fermentation to produce high-value enzymes and animal feed, there is production of greenhouse gases (GHG) which must be taken into account. In this perspective, this study is unique that discusses the GHG emission analysis of agro-industrial waste management strategies, especially apple pomace waste management and repercussions of value-addition of these wastes in terms of their sustainability using life cycle assessment (LCA) model. The results of the analysis indicated that, among all the apple pomace management sub-models for a functional unit, solid-state fermentation to produce enzymes was the most effective method for reducing GHG emissions (906.81 tons CO2 eq. per year), while apple pomace landfill resulted in higher GHG emissions (1841.00 tons CO2 eq. per year). The assessment and inventory of GHG emissions during solid-state fermentation gave positive indications of environmental sustainability for the use of this strategy to manage apple pomace and other agricultural wastes, particularly in Quebec and also extended to other countries. The analysis and use of parameters in this study were drawn from various analytical approaches and data sources. There was absence of some data in the literature which led to consideration of some assumptions in order to calculate GHG emissions. Hence, supplementary experimental studies will be very important to calculate the GHG emissions coefficients during agro-industrial waste management.  相似文献   

9.
Remanufacturing can reduce the energy intensity and associated greenhouse gas (GHG) emissions significantly and increase the eco-efficiency of product systems by utilizing recovered end-of-life parts. This paper presents the GHG mitigation potential of technically feasible remanufactured alternators in Indonesian small- and medium-sized enterprizes. Life cycle assessment approach and Weibull ++8 software have been used to calculate environmental and quality parameters. Since existing remanufactured alternators have not been found to meet the technical criterion for customers’ satisfaction, a number of alternative remanufacturing strategies have been explored to identify an option that has not only reduced GHG emissions but also has satisfied reliability, durability and warranty period criterion. Three improvement scenarios involving three different remanufacturing strategies were investigated in this case study, and yielded useful insights in order to come up with a technically feasible remanufacturing strategy for reducing a significant amount of GHG emissions. The improvement scenario III, which maximizes the use of used components, was found to offer technically and environmentally feasible remanufacturing solutions. Overall, this research has found that about 7207 t of CO2 -eq GHG emissions and 111.7 TJ embodied energy consumption could potentially be avoided if 10 % of alternators in Indonesian automobile sector are remanufactured using technically feasible remanufacturing strategy.  相似文献   

10.
Wastewater treatment plants (WWTPs) are one of the important sources of greenhouse gas (GHG) emission. There is a need for systematical tool that can be used to analyze GHG emission from WWTPs, and to evaluate the associated reduction strategies. In this paper, a systematic analysis methodology, called the greenhouse emission pinch analysis (GEPA), is developed for this purpose. GEPA is graphical in nature, and can be used to analyze the on-site and off-site GHG emissions of the WWTP. Furthermore, three GHG reduction strategies, i.e., increased aeration capacity, external carbon source controller, and reuse of biogas, are evaluated for their environmental load and operational cost reduction using the GEPA. A case study is used to elucidate the proposed method. In this study, the third strategy which reuses biogas from anaerobic digestion shows the largest reduction of GHG emissions.  相似文献   

11.
In the present study, attempts were made to synthesize Mg–Al hydrotalcite-like materials with bifunctional properties from flyash and flyash-based zeolite by coprecipitation method. The synthesized hydrotalcite and their corresponding Mg–Al mixed oxides obtained after calcination were characterized for their structural, compositional, thermal, and morphological properties. The synthesized hydrotalcite had Mg/Al ranging from 1.3 to 2.3. The activity of the synthesized catalyst was estimated in transesterification of mustard oil, and the effects of reaction time, catalyst concentration, and methanol-to-oil molar ratio on biodiesel production were also investigated. A maximum yield of 93.4 % was obtained with methanol-to-oil molar ratio of 12:1, 7 wt% catalyst concentration for 6 h of reaction at 65 °C. The average value of activation energy of biodiesel in the conversion range of 0.2 < X < 0.9 was 130.5 kJ mol?1. This study showed the potential application of flyash and its use in modified Mg–Al hydrotalcite materials as heterogeneous catalysts in biodiesel production.  相似文献   

12.
In this study, the microstructure of AA 2195 T81 metal-cutting chips formed during a turning operation were characterized using microscopy and diffraction techniques. At a constant strain of 2, the resulting strain rate imposed on the metal was varied from 0.8 × 104 to 2.6 × 105 s?1. At strain rate of 0.8 × 104 s?1, the resulting microstructure contained regions of 100 nm ultrafine grains. At the highest strain rate of 2.6 × 105 s?1, 150–200 nm ultrafine grains were observed plus overaged precipitates. The grain size increment and appearance of overaged precipitates with the higher strain rate is conjectured to be a result of temperature increment and not of direct strain rate.  相似文献   

13.
The Sm-doped MeWO4 (Me = Ba, Sr, Ca, and Mg) phosphors were synthesized with a sol–gel method and studied for their microstructures and photoluminescence efficiencies. The hosts of the phosphors show very weak blue emissions except for the MgWO4. The Sm3+ cation in the all hosts shows red emissions. Significantly, the photoluminescence efficiency of Sm3+ in CaWO4 and BaWO4 was largest as the calcination temperature equals 600 and 700 °C, respectively. The BaWO4 may be a new potential host of rare earth-doped phosphors.  相似文献   

14.
Emission of CO2, CH4, and NO x is among the main sources of greenhouse gases (GHGs) emitted through human activities such as fossil fuels combustion for power, heat and transportation, industrial processes, and land-use change. Low-carbon emission has become synonymous with GHG emission, which is often expressed in t CO2 eq. as derived from the major GHG. However, CO2 emission from fossil fuel constitutes just about 2/3 of GHGs. Low-carbon emission has received high publicity in recent years as a major reason for the potential mitigation of climate change. Achieving low GHG emission targets while decoupling the economic growth from high emissions, pollution, and resource use is desirable. This paper reviews the low-carbon emissions initiatives to develop resilient growth strategies to reduce GHG emissions in Asia and beyond. Four major initiatives, including the modelling of GHG emission and mitigation initiative; sustainable energy systems; sustainable waste management; and education and community outreach, are reviewed for mobilising the potential towards low-carbon emissions societies in Asia. Cooperation from major stakeholders, e.g. government, policy makers, financial institutions, private investors, industrial, commercial sector, residential, has been needed towards realising the goal.  相似文献   

15.
The samples with nominal composition of Bi16Pb0.4Sr2Ca2?x Eu x Cu3O y where x=0.000, 0.025, 0.050, 0.100, and 0.200 prepared by co-precipitation method (COP) have been investigated. They were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), electrical and resistivity measurement using the four-probe method. The temperature dependency on electrical resistance showed the superconducting behavior for all the samples. The critical current density (J c ) and superconductivity transition temperature (T c?zero) of Eu substituted were found to be lower than those of the pure sample. T c?zero varied between 100 and 73 K towards Eu concentration with the highest T c?zero in the Eu substitution was found at 98 K for x=0.025 and decreased gradually for further substitution of Eu corresponding to a small change in the carrier concentration. J c decreased with increasing Eu substitution, and it was measured to be at 5.7512 A/cm2 in the Eu free sample and at 2.1223 A/cm2 for the x=0.025 sample at 77 K. XRD analyses showed the decrease of the volume fraction of Bi-2223/Bi-2212 (%) which were estimated from 78.13/21.87 for x=0.000 to 23.18/76.82 for x=0.200. The crystallographic structure was found to change slightly from tetragonal to orthorhombic in Eu substituted samples. The lattice parameter c of the Eu samples decreased due to the incorporation of Eu3+ (0.95 Å) with smaller ionic size at the Ca2+ (0.99 Å) site. From the SEM investigation, the grain connectivity became weak and the porosity increased with the increment of Eu concentration, resulting in the decrease of J c .  相似文献   

16.
Accurate measurements of enthalpy increment (H T ? H 298.15) values have been made on a Ti–5 mass% Ta–1.8 mass% Nb alloy using the inverse drop calorimetry technique in the temperature range from 463 K to 1457 K. The measured enthalpy increment values show a steady increase with temperature in both α-hcp and β-bcc solid solution regions. It is found that both the onset as well the completion of the αβ phase change are demonstrated by a marked deviation of the enthalpy increment behavior from the otherwise smooth variation encountered in the respective low-temperature α- and high-temperature β-phase domains. The transformation start (T s) and finish (T f) temperatures of the αβ phase change are found to be (1072±10) K and (1156±10) K, respectively. In the actual αβ phase transformation region, the variation of the enthalpy with the progress of transformation is found to follow a sigmoidal shape which is in line with the diffusive nature of the phase transformation. An estimation of the total enthalpy change associated with the αβ phase transformation (Δ°H tr) has been made by assuming a simple diffusion limited kinetic model for the phase change. The net enthalpy change for the αβ transformation is found to be 76 J · g?1. The measured temperature variation of the enthalpy increment in both α- and β-phase regimes are fitted to simple analytical functional forms to obtain temperature-dependent estimates of the specific heat, C P . The total specific heat change associated with the αβ phase transformation ${\Delta^{\circ}{C_{P}^{\alpha}}^{\rightarrow{\beta}}}$ is estimated to be 904 J · kg?1 · K?1.  相似文献   

17.
大气中温室气体浓度的增加引起的全球气候变化是世界关注的焦点问题。在所有的排放源中,固定排放源排放的二氧化碳气体是温室效应的主要因素。政府间气候变化专门委员会(IPCC)将直接测量排放量方法列为温室气体排放清单统计的最高等级,以提高数据统计精度。为了实现排放量的精确测量,固定排放源浓度直接测量至关重要。基于分析吸收光谱建立了相对于纯气体的测量方法,通过多次反射直接吸收光谱技术,建立了精确测量二氧化碳浓度的相对法装置,测量了293 K和0~13 kPa下二氧化碳在6 362.5 cm-1的(30012)←(00001)R20e跃迁谱线,通过与纯二氧化碳吸收面积的比较得到15%,35%,50%和75%二氧化碳混合物的浓度。结果表明与天平称重法得到的结果具有很好的一致性,相对扩展测量不确定度在0.7%以下(k=2)。  相似文献   

18.
In this paper, the influence on the system performance and greenhouse gas (GHG) emissions of different biomass pretreatment methods before gasification and Fischer–Tropsch (FT) crude production was evaluated. Entrained flow gasification has the benefit of producing a practically tar-free synthesis gas with nearly complete carbon conversion. This gasifier type requires a relatively dry fuel, with small particle size, at high pressure. The size can be acquired by milling, which is energy intensive and feeding is challenging. Torrefaction of biomass facilitates milling; it thus requires less electricity, however, the torrefaction process requires heat. Pyrolysis decomposes the biomass into gaseous, liquid, and solid parts, respectively. This further makes feeding easier, but comes with a greater heat demand than torrefaction. The impact of the different pretreatment methods on the overall energy system has been evaluated using process integration methodology. The results show that the excess heat from an FT process with a biomass input of 300 MWHHV can replace the bark boiler in a large chemical pulp and paper mill, producing 350,000 tonnes of bleached paperboard annually. With the preconditions given for this study, thermal pretreatment of biomass may be beneficial in terms of wood-to-FT crude efficiency, with efficiencies up to 68 %, assuming 40 % electrical efficiency. Pretreatment using pyrolysis performed the best in regards to GHG emissions, if CO2 from acid gas removal was vented, while milling, with an annual reduction of around 700,000 tonnes of CO2,eq, had the best results if the CO2 was captured and sequestrated.  相似文献   

19.
The application of strippable coatings is an innovative technology for decontamination of nuclear plants and for any decontamination project aiming at removing surface contamination. An adhesive plastic coating is applied on the contaminated surface. The strippable coating is allowed to cure for up to 24 h, after which it can be easily peeled. The coating traps the contaminants in the polymer matrix. Strippable coatings are non-toxic and do not contain volatile compounds or heavy metals. Since the coating constitutes a solid waste, disposal is easier than treating contaminated liquid wastes, produced by the baseline technology: steam vacuum cleaning, based upon superheated pressurized water in order to remove contaminants from floors and walls. A life cycle assessment (LCA) has been carried out with the purpose of comparing the strippable coating with the steam vacuum technology. The functional unit of the study is represented by a surface of 1 m2 to be decontaminated. The results of LCA achieved using Sima Pro 5.0® software confirm the good environmental performances of strippable coatings. Taking into account both LCA and environmental costs for liquid wastes, the advantages of strippable coatings will be more and more evident.  相似文献   

20.
Realizing a sustainable development of our planet requires a reduction of waste production, harmful emissions, and higher energy efficiency as well as utilization of renewable energy sources. One pathway to this end is the design of sustainable biorefinery concepts. Utilizing waste streams as raw material is gaining great importance in this respect. This reduces environmental burden and may at the same time contribute to economic performance of biorefineries. This paper investigates the utilization of slaughtering waste to produce biodegradable polyesters, polyhydroxyalkanoates (PHA), via bioconversion. PHA are the target product while production of high quality biodiesel along with meat and bone meal (MBM) as by-products improves the economic performance of the process. The paper focuses on ecological comparison of different production scenarios and the effect of geographical location of production plants taking different energy production technologies and resources into account; ecological footprint evaluation using Sustainable Process Index methodology was applied. Keeping in mind that the carbon source for PHA production is produced from waste by energy intensive rendering process, the effect of available energy mixes in different countries becomes significant. Ecological footprint results from the current study show a bandwidth from 372,950 to 956,060 m2/t PHA production, depending on the energy mix used in the process which is compared to 2,508,409 m2/t for low density polyethylene.  相似文献   

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