Search

Fast pyrolysis of biomass and upgrading techniques for the high chemical value bio-oil production have been investigated widely in recent decades. A variety of upgrading techniques are applied in industrial manufacture process, while the production efficiency and sustainability of those techniques have their own merits and demerits, which emphasizes the importance of the evaluation systems for those techniques. Several evaluation methods, such as energy analysis, exergy analysis, and emergy analysis, have been developed to evaluate the fast pyrolysis of biomass and upgrading techniques. Based on different emergy flows, the methods chosen for the thermodynamic analysis lead to various outcomes. All the input and output energies in an industrial production system are considered in energy analysis, while exergy analysis takes the additional available energy into account. In emergy analysis, all kinds of emergy flows are taken into consideration, including monetary flow, information flow and energy flow. Emergy analysis is derived from the viewpoint that the sun provides the energy for everything on the earth so it is reasonable to convert all kinds of energy to the solar energy. It is so efficient and comprehensive that it has been applied to evaluate the fast pyrolysis of biomass and upgrading techniques. Based on the input-output framework and emergy indices, with the consideration of environment elements, emergy analysis method was applied to comprehensively evaluate two schemes in this paper, achieving upgraded bio-oil from pinus sylvestris by fast pyrolysis and catalytic hydrogenation (Scheme I) and supercritical ethanol upgrading technique (Scheme II), respectively. Meanwhile, the effects of different schemes were compared from three aspects, including production efficiency, environmental support and sustainability. As the results indicated, Scheme II consumed less solar energy and enjoyed higher efficiency when the same amount of fuel was produced. For the input of economic emergy and total emergy, Scheme I were 4.58×1020 and 4.64×1020 sej/a while Scheme II were 5.82×1020 and 5.88×1020 sej/a respectively, which showed that Scheme I needed less economic emergy input and total emergy input by contrast with Scheme II. For the renewable ratio, Scheme I was 49.57 while Scheme II was 39.12, which showed that renewable emergy input occupied higher percent of the total emergy input in Scheme I. For the environment sustainable index, Scheme I was 0.99 while Scheme II was 0.65, which showed that Scheme I had less stress on the environment and got more support from it. In brief, Scheme I achieves larger renewable ratio, less environment stress, better sustainability and greater environmental support. The optimal direction for both Scheme I and Scheme II is to reduce the emergy input. Scheme I focuses on improving the efficiency of emergy conversion, while Scheme II emphasizes on adjusting the process to reduce the dependency on external support. Compared with the results of energy analysis and exergy analysis, Scheme II needs more total inputs and total energy consumptions, while Scheme I has higher exergy efficiency. Scheme I and Scheme II shared the same emergy yield ratio, which indicated emergy analysis could provide a more comprehensive and deeper evaluation. In sum, theoretical foundations on improving the integrated performance of fast pyrolysis of biomass and upgrading techniques for the bio-oil production are achieved in this paper. [ABSTRACT FROM AUTHOR]

Protected agriculture was one of the highest forms of modern agriculture, which had been the focus of world agricultural development in each country. The demand for organic fruit and vegetables accounted for around 30%-40% of the global demand, but the total area for organic vegetable production was only 0.5% of the total area of vegetables grown in the world. Although it was generally considered that the output of organic agriculture was 10%-20% lower than that of conventional agriculture, it exceeded conventional agriculture in terms of economic benefits, environmental impact, and social benefits. It also had a positive performance in providing nutrition, adapting to climate change, promoting soil health, protecting biodiversity, increasing employment and creating new economic model. In the face of rapid population growth, climate change and environmental degradation in the 21st century, new organic greenhouse horticulture was the major force for sustainable agricultural development. The total area for organic greenhouse horticulture was estimated to be over 8302 hm2 (1.8% of total vegetable greenhouse area). There were 5236 hm2 in European Union and 3066 hm2 in Non-European Union. With the rapid development of agriculture in the world, the organic greenhouse horticulture had been shown to be sustainable, productive and profitable in foreign countries, but the standards of organic greenhouse horticulture were still a blank in China. This paper introduced the background, definition, origin, objectives, area of organic certification, yield and profitability, the basic forms of organic greenhouse horticulture and the rules of certification, and analyzed the feasibility and problems on the organic greenhouse horticulture in China: 1) Certification standards of organic greenhouse horticulture were lacked. 2) Greenhouse ecological environment had been deteriorated. 3) Plant varieties for greenhouse were scarce. 4) There were only a few studies on organic greenhouse horticulture. The feasibility of the development of organic greenhouse horticulture in China was further analyzed. It was suggested that organic greenhouse horticulture should be actively developed in China, but organic greenhouse horticulture cannot be simply equivalent to “greenhouse + organic planting”. It should be an integration with sustainable development, which consisted of greenhouse climate control, planting material, soil fertility, water management, disease and pest management, energy conservation and sustainability. However, to promote the development of organic greenhouse horticulture in China, we need to implement it based on national conditions and learn the rules of the foreign organic greenhouse horticulture. Moreover, the basic research of the biological agriculture in our country should be strengthened: 1) Strengthen the formulation of organic farming laws and industry standards in China, and point out the development goals and technical requirements of organic greenhouse horticulture. 2) Strengthen basic research in bio-agriculture to propose novel theories, technologies and equipment for protected agriculture. 3) Strengthen the development of agricultural machinery for organic greenhouse horticulture. The aim was to compensate for the lack of manpower, increase production efficiency and transform people’s bias that organic agriculture has low yield and inefficiency. 4) Strengthen the demonstration and promotion of organic facilities horticultural technology integration. We need to construct a diversified organic facility horticultural extension service system with national public welfare promotion institutions as the main body, scientific research units, colleges and universities, agriculture-related enterprises, professional cooperative organizations and consumers participating in it. The system can provide information and technical services for farmers and consumers, which can ensure the sustainable development of the protected agriculture industry in China. [ABSTRACT FROM AUTHOR]

With the rapid development of bioenergy, the sustainability issue of bioenergy has aroused more and more attention globally. China is also highly concerned about the sustainable development of bioenergy. But, there are only sustainable principles emphasized by government with no specific criteria and indicators, e.g., avoiding bioenergy competition for food crops and land. Therefore, it is necessary to establish systematic criteria and indicators to provide clear and executable guidelines for the sustainable development of bioenergy in China. Several regions in the world have promulgated regulation framework or certification standard to assure the sustainable production and utilization of bioenergy. Also some international institutions, such as Global Bioenergy Partnership (GBEP) and International Organization for Standardization (ISO), have published voluntary sustainable standard for decision makers. Therefore, to learn the global experience is a good option to promote the establishment of sustainable requirements in China. The typical sustainable bioenergy initiatives in the world are introduced in the paper, including regulation frameworks, certification standards and voluntary standards without threshold. The key criteria and indicators are reviewed. It is found that although the principles of sustainable development are the same for diverse initiatives, their focuses on environmental, social or economic aspects are different due to their different starting points and goals. The importance of involving greenhouse gas (GHG) emission as a key indicator is analyzed, and the challenges on how to quantify GHG emission are also discussed, such as, the allocation of byproduct’s emission and the impact of direct land use change & indirect land use change. The requirements on GHG emission reduction of bioenergy compared to fossil fuel are also reviewed. The supporting role of bioenergy sustainability initiatives for the bioenergy industrial policies is elaborated based on the practices of the EU (European Union) and the United States. And finally, related policy suggestions in China are proposed. The suggestions include: 1) Sustainability requirement (criteria or indicators) of bioenergy should be proposed in Renewable Energy Law and Bioenergy Development Planning in China to guide the direction of industrial development; 2) the criteria and indicators of sustainable bioenergy should be both scientific and implementable with clear goals and focus, and should be selected based on domestic situation; 3) GHG emissions counting methodology of different kinds of bioenergy should be provided by government to facilitate industries to meet the sustainability requirement, and the threshold of life cycle GHG emission reduction of bioenergy needs to be fully discussed with stakeholders and strengthened gradually; 4) priority should be given to aviation biofuels, bioenergy derived from residues and wastes, and systematic sustainability criteria and indictors should be established for other biofuels for transportation use in the near term; and, 5) the industrial policies and research and development funding of bioenergy should be linked with the sustainability requirements, and the policy support should be inclined to the sustainable production and utilization of bioenergy which can meet the requirements. [ABSTRACT FROM AUTHOR]