Does the production of Belgian bioethanol fit with European requirements on GHG emissions? Case of wheat

This paper undertakes an environmental evaluation of bioethanol production, using wheat cultivated in Belgium. Cultivation steps are modelled using Belgian specific data. Wheat transformation in ethanol relies on industrial data. GHG emissions of the whole life cycle are calculated and compared with the default values given by the European Renewable Energy Directive. Belgian wheat bioethanol achieves a 5% higher GHG reduction than the one mentioned in the European directive but impact repartition is different with a higher importance of cultivation step in our case. Belgian wheat bioethanol complies with the current sustainability criteria but is also able to conform to further ones. Sensitivity analyses are performed on the importance of N fertilizers and associated emissions known as main important parameters. These analyses reveal non negligible variations and then a range of available GHG reduction when using wheat bioethanol.     

Top-k-size keyword search on tree structured data

Keyword search is the most popular technique for querying large tree-structured datasets, often of unknown structure, in the web. Recent keyword search approaches return lowest common ancestors (LCAs) of the keyword matches ranked with respect to their relevance to the keyword query. A major challenge of a ranking approach is the efficiency of its algorithms as the number of keywords and the size and complexity of the data increase. To face this challenge most of the known approaches restrict their ranking to a subset of the LCAs (e.g., SLCAs, ELCAs), missing relevant results.In this work, we design novel top-k-size stack-based algorithms on tree-structured data. Our algorithms implement ranking semantics for keyword queries which is based on the concept of LCA size. Similar to metric selection in information retrieval, LCA size reflects the proximity of keyword matches in the data tree. This semantics does not rank a predefined subset of LCAs and through a layered presentation of results, it demonstrates improved effectiveness compared to previous relevant approaches. To address performance challenges our algorithms exploit a lattice of the partitions of the keyword set, which empowers a linear time performance. This result is obtained without the support of auxiliary precomputed data structures. An extensive experimental study on various and large datasets confirms the theoretical analysis. The results show that, in contrast to other approaches, our algorithms scale smoothly when the size of the dataset and the number of keywords increase.     

Optimization of environmental impact reduction and economic feasibility of solvent waste recovery using a new software tool

The environmental impact reduction and operating costs savings associated with the purification and recovery of solvent waste in the manufacture of active pharmaceutical ingredients (API's) were investigated. A software toolbox has been developed that combines Aspen Plus^® process simulation with SimaPro^® and Ecosolvent life cycle assessment (LCA) databases. A LCA approach was used in order to consider the environmental impact beyond pharmaceutical production plant boundaries. The feasibility of a relatively small flexible equipment-skid capable of recovering multiple solvent waste streams was evaluated. Distillation and pervaporation were considered to separate binary waste solvent mixtures. Optimum distillation reflux ratio and feed stage were determined to maximize the environmental impact reductions and operating cost savings. The optimum reflux ratio was significantly higher than 1.2 times the minimum reflux ratio suggested by traditional heuristics. The emissions and cost reductions obtained were as much as 49% and 56% higher, respectively, as compared to using the conventional optimum reflux ratio. A comprehensive cash flow analysis showed that the recovery of low volume solvent waste streams is economically feasible, despite traditional thinking. Three case studies from Pfizer are presented to show how our software tool can aid in green engineering decision making.     

OEM汽车涂装车间技术的环境生命周期评价（一）

生命周期评价（LCA）是一种评价产品系统的环境影响和环境权衡的标准化方法。伊士曼化工公司完成了一项＂从涂料到成品车涂装＂的LCA研究,在该研究中,比较了5种有代表性的OEM汽车涂装车间工艺配置的温室气体（GHG）影响和挥发性有机化合物（VOC）排放性能。涂装车间数据由IHS提供。这些工艺配置包括：1）三涂两烘（3C2B）水性（WB）底色漆和1K罩光清漆;2）3C2B WB底色漆和2K罩光清漆;3）3C2B低固含溶剂型底色漆和1K罩光清漆;4）三涂一烘（3C1B）高固含溶剂型底色漆和1K罩光清漆;5）3C1B WB底色漆和1K罩光清漆。本研究的目标是通过比较通用工艺技术类别来帮助理解差异和制定决策。本研究的结论是,3C1B高固含溶剂型工艺可以实现最低的GHG释放量,同时达到欧洲现行的VOC排放限值35 g/m2。但是,如果世界上某些地区的OEM选择不采用VOC减排技术,那么为了达到排放限值35g/m2,需要采用WB技术。这项LCA研究表明,高固含溶剂型技术是对环境影响最小,有利于可持续性发展的技术,建议政策制定者和利益相关者予以考虑。     

建设项目施工阶段环境影响评价研究

LCA(Life-Cycle Assessment)是评价产品从“摇篮到坟墓”(Cradle to Grave)的生命周期内对环境影响的一种评价方法。随着环境问题的日益严重,目前世界许多国家都在深入研究LCA在产品环境影响评价中的应用,并根据各自情况制定相应的评价模式和标准。本文按照LCA的评估原理,从评价的目标与范围界定、清单分析、影响评价和解释说明等四个环节,讨论如何运用LCA工具评估建设项目施工阶段的环境影响,建立具有可操作性的环境评价指标模型,对项目施工的环境友好性进行系统评价,从而改进建设项目环境管理,促进建筑业可持续发展。     

粉煤灰再生混凝土生命周期评价初探

本文使用生命周期评价(LCA)方法对掺与不掺粉煤灰的再生混凝土的环境影响进行评价。研究表明，再生混凝土是一种很好的环境材料(ecomaterial)。粉煤灰的掺入可以提高再生混凝土的绿色度。不掺粉煤灰的再生混凝土可以有效的减少油耗、CO、CxHy以及废弃物的排放，但并不能有效的减少混凝土的煤耗、CO2、NOx以及SO2排放置；而通过掺入粉煤灰可使再生混凝土的各项污染指标均得到有效的降低。     

Effects of increased wood energy consumption on global warming potential,primary energy demand and particulate matter emissions on regional level based on the case study area Bavaria (Southeast Germany)

Wood energy use has strongly increased in Europe in the last decade entailing enhanced resource competition between the wood energy sector and the material-based wood sector. We applied the basket of benefit method for the forestry and wood cluster of the study area Bavaria to evaluate the impact of increased wood energy use and decreased material-based wood use on global warming potential, primary energy demand and particulate matter emissions. A baseline and a wood energy scenario were developed until 2035 and wood utilization in both scenarios was assessed via a Life Cycle Assessment of prevalent wood products, imported timber and conventional alternatives of use. The study reveals that, according to the modelled scenarios and the average substitution factors used, a demand shift towards more wood energy leads to a minor increase in global warming potential and to a reduction in primary energy demand. Increase in particulate matter emissions from wood energy use is strong, but definite conclusions cannot be drawn due to lack in data for material-based wood use. Moreover, the study results vary strongly depending on the products used for the comparative analysis. Through our approach, the ecological impact of increased wood energy use becomes visible for a whole region, taking into account the effect of a demand shift and of interdependent substitution effects.     

Life cycle assessment of domestic fuel cell micro combined heat and power generation: Exploring influential factors

Residential Fuel Cell micro combined heat and power (FC-μCHP) systems can help decarburizing the energy system. In the European ene.field project, the environmental performance of FC-μCHP under different conditions was therefore evaluated by means of a comprehensive Life Cycle Assessment (LCA). Important influential factors were explored, i.e. heating demands, full load hours (FLHs) and electricity replacement mixes (ERMs). The systems were compared with a stand-alone Gas Condensing Boiler (GCB) and a heat pump (HP, only in single family homes, SFHs). For the initially assumed FLHs and the current ENTSO-E ERM, relevant environmental impacts including climate change are generally smaller for the FC-μCHPs than for the HP and the stand-alone GCB. In the setting “existing SFHs in central climate” with the highest deployment potential, GHG emission savings are higher the more carbon-intensive the ERM is and/or higher the net electricity export into the grid is. The results are discussed and put into perspective. Further research demands as well as product development opportunities are outlined. The importance of a green hydrogen economy is emphasized.     

Evaluation of the environmental impacts of rare earth elements production

This study aims to estimate the emissions and evaluate the environmental impacts from the production of rare earth elements (REEs). The life cycle assessment method was used to evaluate the environmental load from the production of each metal. To understand the environmental impacts of REEs production, they were compared with the impacts from the production of base metals and precious metals. The findings of this study should present a scientific baseline for the environmental profile for producing these REEs, which might help lessen their impacts and improve production processes and technologies.     

Greenhouse gas and energyassessment of the biogas from co-digestion injected into the natural gas grid: A Swedish case-study including effects on soil properties

In this study, a large, farm-based, co-digestion plant in southern Sweden, using manure and various food industry wastes is investigated concerning its use of energy and its emissions of greenhouse gases from a life cycle perspective based on measured, site-specific data. The biogas is upgraded and utilized as a vehicle fuel, distributed via the natural gas grid. The case-study also includes a novel approach in which potential changes in soil compaction and soil carbon levels are assessed, based on farm-specific conditions, when digestate replaces mineral fertilizer. An additional objective is to identify potential technical improvements leading to further GHG reductions, and the cost of such measures. According to this case-study, biogas produced from food industry waste and manure in a modern co-digestion plant could reduce GHG emissions by approximately 90% compared to conventional fossil fuels. The corresponding energy input:output ratio is calculated to be about 25%, where the use of electricity in the biogas process, upgrading and pressurisation is the dominating energy input. Finally, several possible technical improvements to further reduce GHG emissions were identified. The economic prerequisites of the specific improvements varied, from profitable from a business perspective to unprofitable from a socio-economic point-of-view.