Biomass最新文献

Dramatic gains in tree growth can be achieved by today's breeding techniques. However, much of these gains may be lost due to pathogen-caused diseases and insect attack. The use of pesticides in energy plantations is undersirable because of their possible ecological impacts and public concern regarding their harmful side effects. Conventional breeding programmes, geared to produce pest-resistant trees, are slow and require a large number of plants and space. Therefore, alternative techniques which use more powerful tools have to be employed to accelerate the processes that produce effective methods of pest control. Biotechnology, employing cell and tissue culture, cell fusion, recombinant DNA technology for cell cloning, and genetic engineering, is a new and rapidly developing field/science. Moreover, it seems ideally suited for the development of pest-resistant plant material for energy plantations.

Because of the timeliness of this technology in developing pest-resistant plant material, the International Energy Agency (IEA) Bioenergy Agreement initiated a special project to examine this proposal. The present paper summarizes the results of several workshops held by the representatives of the IEA member countries on this topic. Different techniques of biotechnology, their beneficial effects as well as some of their weaknesses, are discussed.

During the 3 years from 1986 to 1988, two International Energy Agency projects, CPD 2 (Pretreatment of Lignocellulosics) and CPD 5 (Conversion of C5, Sugars to Ethanol), were combined to form Task IV — Bioconversion of Lignocellulosics. Two meetings were held, the first in Graz, Austria in 1986 and the second in Ottawa, Canada in 1988. Proceedings from each of these meetings were distributed among the participants. Round-robin tests on the chemical analysis of pretreated lignocellulosic substrates and the enzymatic hydrolysis of these substrates were carried out by the network participants. Industrial groups from member countries were invited to participate at the Ottawa meeting. Various economic models were presented to determine the technoeconomic factors influencing the commercial viability of a bioconversion process. The success of the network was reflected in the attendance at the meetings, the excellent rapport of the participants and the useful information arising from the round-robin comparisons.

Nicotiana glauca R. C. Graham is a member of the Solanaceae, naturalized in the areas of warm-arid climates of the Iberian Peninsula. This species could have a great importance as a possible energy crop, because of its drought hardiness, sprouting capacity, large biomass productivity and high content of non-structural carbohydrates. In this work the production of the above-ground biomass of Nicotiana glauca was studied in relation to the irrigation regime in a cycle of cultivation. Primary values — leaf area, leaf dry weight and stem dry weight — were determined by non-destructive methods, in order to follow individually the development of each plant. From these primary values, growth indexes were calculated, and the behaviour of the species is discussed in relation to the environment. From the results obtained, it is deduced that Nicotiana glauca is a species adapted to conditions of water deficit and high temperatures. It is concluded that Nicotiana glauca could be cultivated in marginal lands of warm-arid climates; and a production of above-ground biomass of 3·9 t d.m. ha⁻¹ year⁻¹ was estimated, from which it would be possible to extract about 900 kg of easily fermentable carbohydrates.

An indirect-fired biomass furnace was used to determine the thermal energy available from rice straw, Dallis bermudagrass and sugarcane bagasse. Bomb calorimetry was used to determine the energy content of the agricultural biomass. Temperature, airflow and relative humidity measurements were made to determine the heat utilized for drying. Three batches of rough rice were dried from 21 to 12·7% moisture with average furnace efficiency of 41% for rice straw and bermudagrass bales. Drying efficiency of over 60% was achieved with air temperature rise of at least 5°C.

Conventional harvesting operations currently collect large quantities of biomass used for energy generation in the form of hog fuel and black liquor produced as by-products at sawmills and pulpmills. An increase in this quantity will be obtained from integrated systems when components of existing harvesting tasks are improved, in particular delimbing by processing trees in bulk. Methods to improve profitability by the optimum allocation of the various portions of a tree to the different products, including energy wood, are being successfully implemented through the use of computer-based bucking algorithms.

This paper reports on the authors' efforts to improve the small farm community welfare in Kenya by promoting biogas technology. The survey showed that fuel was used in Kenyan farms mainly for cooking and lighting, and wood, crop residue, and charcoal were the predominant fuel sources. Mostly women collected firewood, fetched water, and cooked. Building a fire with these fuels was time-consuming, and smoke from these fires was damaging to the living environment. Hence, applying biogas technology to Kenyan small farms not only guarantees a reliable, renewable energy source, but also provides other benefits, such as cleaner household environments, better working conditions for housewives,