Brown rot fungal early stage decay mechanism as a biological pretreatment for softwood biomass in biofuel production

A current barrier to the large-scale production of lignocellulosic biofuels is the cost associated with the energy and chemical inputs required for feedstock pretreatment and hydrolysis. The use of controlled partial biological degradation to replace elements of the current pretreatment technologies would offer tangible energy and cost benefits to the whole biofuel process. It has been known for some time from studies of wood decay that, in the early stages of growth in wood, brown rot fungi utilise a mechanism that causes rapid and extensive depolymerisation of the carbohydrate polymers of the wood cell wall. The brown rot hyphae act as delivery vectors to the plant cell wall for what is thought to be a combination of a localised acid pretreatment and a hydroxyl radical based depolymerisation of the cell wall carbohydrate polymers. It is this quality that we have exploited in the present work to enhance the saccharification potential of softwood forest residues for biofuel production. Here we show that after restricted exposure of pine sapwood to brown rot fungi, glucose yields following enzymatic saccharification are significantly increased. Our results demonstrate the potential of using brown rot fungi as a biological pretreatment for biofuel production.     

Price relationships and market integration in the Swedish wood fuel market

Cointegration analysis is applied to the prices of three different wood fuel assortments in the Swedish market: refined wood fuels, forest chips and industrial by-products. For the latter two, the price series are separated according to two consumer categories: district heating (DH) plants and industrial consumers. Two types of analyses are performed. The first concerns whether the fuels within each consumer group can be bundled together as belonging to the same market in terms of product homogeneity. The second involves analysis of the prices of homogeneous fuels in the two consumer categories. It is found that in the DH sector, refined wood fuels should be observed as a separate market because their prices do not share a common trend with the prices of any of the other fuels. This lack of a common trend is likely due to the highly internationalized nature of the wood pellet market. The DH prices of forest chips and industrial by-products follow a common trend, as do the prices paid for industrial by-products by DH plants and industrial consumers. The prices of forest chips paid by industrial consumers and DH plants do not share a common trend. The prices paid by industrial consumers for industrial by-products and forest chips also do not share a common trend. These results highlight both the differences between the markets for unrefined and refined wood fuels and the presence of inefficiencies in the Swedish wood fuel market.     

Availability and conversion to energy potentials of wood-based industry residues in Cameroon

The importance of biomass as the most accessible primary energy source in Cameroon is presented. The valorization of wood wastes and residues is seen as a way of implementing the sustainable use of biomass resources. A recent survey of wood-based industries in Cameroon reveals that large volumes of industrial wood residues are generated in the rain forest areas and are unefficiently used. Important quantities are lost in the form of burning in the four main forestry provinces, while other parts of the country suffer from fuelwood shortage. With the exception of the plywood factories, the wood industry is essentially dependent on commercial energy. An analysis made to show the economic and environmental benefits of converting wood residues to energy for industrial and domestic use is presented.     

Biomass cofiring: economics, policy and opportunities

The US Department of Energy (DOE), Electric Power Research Institute (EPRI) and utilities are evaluating, testing and applying technology that can give a new, and potentially profitable, mission to existing coal-fired power plants. The oldest of all fuels, wood, and the old original fuel of the industrial revolution, coal, are key to this move to a new mission. Technical issues that can lead to doubt about, or outright rejection of, wood (or biomass) cofiring are, in fact, being resolved through testing and experience. DOE, EPRI and utilities have joined to cosponsor tests in full-sized boilers and design/cost/supply studies related to these tests. Economic calculations, based on the measured performance and on cost estimates confirmed in purchases for the tests, are presented in this paper. The technical feasibility is proved. The constraints are identified. So far, the profits are in the future. Policy changes that produce stronger economic incentives could make profit possible today, and enable this low-cost form of renewable power to be deployed. But, without the policy, or market, change, the economic barrier is a strong one, when biomass cofiring must compete with low-cost coal at low fuel cost and with low-capital-cost gas turbine combined cycle power plants. The economics would not be a barrier at all if biomass cofiring were in competition against moderate-velocity wind power or solar PV power.     

Solar-thermal driven drying technologies for large-scale industrial applications: State of the art,gaps, and opportunities

Research and Innovation (R&I) on Large-scale Industrial Solar-thermal driven Drying technologies (LISDs) is one of the strategies required to transition to a low-carbon energy future. The objective for this work is to guide future R&I on LISDs by defining the state of the art, gaps, and opportunities. To provide a high-level perspective on the current state of solar drying research, results are presented from an analysis of the content relevant to LISDs found in 45 solar drying Review Articles published in journals over the past 25 years. A conclusion is that most of the existing solar drying research is not focused on LISDs. To build-on these existing 45 solar drying Review Articles, results are presented from an analysis of 30 Original Research Articles with significant content relevant to LISDs published over the past 5 years. A gap is identified in coupling existing or slightly modified solar thermal collectors with existing or slightly modified industrial drying technologies to create indirect LISDs. To facilitate formulating new coupling strategies, the drying characteristics most relevant to this coupling are described and four fundamental classes of industrial dryer technologies are defined based on the underlying heat transfer mechanism, which then impacts the appropriate collector choice. At their most fundamental level, many of the technologies needed to couple solar collectors and industrial dryers to create novel indirect LISDs are not unique to indirect LISDs, but rather can be generalized across a wide range of Solar Heat for Industrial Processes (SHIP) applications, and integration issues are discussed at a more fundamental SHIP level. The technical and economic characteristics of 19 existing LISDs installations throughout the world are presented, and potential and emerging areas discussed.     

白腐菌对染料废水脱色的研究

白腐菌利用其分泌的特殊降解酶系或其它机制能将各种合成染料彻底降解为CO2和H2O,并具有良好的脱色效果。实验采用白腐菌为黄孢原毛平革菌,分别研究了不同废水浓度、不同染料废水投加时间、不同染料废水pH值、振荡等条件对模拟染料废水的脱色效果的影响。     

Biological degradation of torrefied wood and charcoal

Torrefaction is an interesting option to pretreat biomass in order to obtain a fuel with improved handling and combustion characteristics, but there are a number of questions related to the supply chain and especially storage. To investigate the susceptibility of torrefied and charred spruce and birch to biological degradation, two experiments were conducted: a controlled laboratory fungal growth experiment with four different wood utilizing fungi and a preliminary field experiment with uncontrolled conditions. In laboratory, changes in moisture content, carbon and nitrogen contents and mass were measured, and the growth of the fungi was determined visually. Increasing pyrolysis temperature decreased fungal growth, but loss of carbon was noted in all of the samples. Fungal growth increased the moisture contents of samples. In the field experiment dry matter loss and increase of moisture content was noted. Torrefied wood and charcoal seem to not have full resistance towards fungal degradation. This creates additional problems that have to be taken into account when planning the supply chain of the material, as outside storage may not be advisable.     

World trade in forest products and wood fuel

Wood fuel is a strategic resource for future energy supply and is usually utilised locally. Traditional use of wood fuel and other bioenergy has a share of 10–15% energy supply, used mainly for the household sector. The utilisation for industrial purposes is much smaller but is a strategic resource in the effort to fulfil the Kyoto agreement to replace fossil fuels and to mitigate greenhouse gas emissions. Many industrialised countries already use a significant share of biofuels in their energy supply e.g. Nordic countries while others like some other European Union countries are planning to increase their use. Production and use of biofuels need to be carried out sustainable. Official statistics do not report trade in such detail that international trade in different biomass types can be fully identified. However, FAO and European Forestry Institute are important sources. In some countries, there is a growing interest in the international trade, because the trade can provide biofuels at lower prices, larger quantities and better quality than domestic alternatives. The first signs of an international market price for wood fuel are indicated in Europe. For the future both the use and the trade of wood fuel is expected to increase. Analyses for trade in charcoal, wood chips, fuel wood and wood residues made in this report identify ‘hot’ trade spots in Europe, in south East Asia and in North America.     

Experimental investigation on the influence of different grades of wood chips on screw feeding performance

Although basic investigations on wood chip material properties haven been carried out, only few studies deal with transport of wood chips, despite the fact that significant problems are commonly observed when feeding biomass in industrial applications. Within the work presented, basic bulk material properties were measured and experiments carried out with a system consisting of a hopper, agitator and a screw conveyor. The aim of this study was to investigate how three different wood chip grades and two blends of wood chips influence typical design parameters, such as mass flow and driving torque, of a biomass feeding system. The measured basic bulk properties are in good overall agreement with the literature. However, discrepancies were discovered between two standardized methods for determination of the bulk density. The results for the driving torque, mass flow and mass-related energy consumption showed that different grades of wood chips can alter these values considerably. Between two wood chip grades, a twice as high torque was recorded, while a third grade could not be fed due to jamming. One of the major findings of this study is that mixing a rather small amount of a high-fine content grade with the non-feedable grade of wood chips resulted in a blend which inhibited jamming during the screw feeding process.     

Future production and utilisation of biomass in Sweden: Potentials and CO2 mitigation

Swedish biomass production potential could be increased significantly if new production methods, such as optimised fertilisation, were to be used. Optimised fertilisation on 25% of Swedish forest land and the use of stem wood could almost double the biomass potential from forestry compared with no fertilisation, as both logging residues and large quantities of excess stem wood not needed for industrial purposes could be used for energy purposes. Together with energy crops and straw from agriculture, the total Swedish biomass potential would be about 230 TWh/yr or half the current Swedish energy supply if the demand for stem wood for building and industrial purposes were the same as today. The new production methods are assumed not to cause any significant negative impact on the local environment. The cost of utilising stem wood produced with optimised fertilisation for energy purposes has not been analysed and needs further investigation. Besides replacing fossil fuels and, thus, reducing current Swedish CO₂ emissions by about 65%, this amount of biomass is enough to produce electricity equivalent to 20% of current power production. Biomass-based electricity is produced preferably through co-generation using district heating systems in densely populated regions, and pulp industries in forest regions. Alcohols for transportation and stand-alone power production are preferably produced in less densely populated regions with excess biomass. A high intensity in biomass production would reduce biomass transportation demands. There are uncertainties regarding the future demand for stem wood for building and industrial purposes, the amount of arable land available for energy crop production and future yields. These factors will influence Swedish biomass potential and earlier estimates of the potential vary from 15 to 125 TWh/yr.     

Pretreatment of Japanese cedar wood by white rot fungi and ethanolysis for bioethanol production

Japanese cedar (Cryptomeria japonica) shares around 60% of plantation forests in Japan, and there is a growing demand for thinning of the forest. However, the softwood is one of the most recalcitrant wood species for hydrothermal and thermochemical pretreatments for enzymatic saccharification. In the present paper, we applied combined pretreatments by solvolysis and cultivation with white rot fungi to develop environmentally benign pretreatment system applicable to recalcitrant softwood. Due to the recalcitrance of the softwood, enzymatic saccharification yield from ethanolysis pulp was 10.2%, based on the weight of holocellulose. To increase the sugar yield, the softwood was treated with selective white rot fungi prior to the ethanolysis. Treatment of the softwood with a biopulping fungus, Ceriporiopsis subvermispora FP-90031 and a new fungal isolate Phellinus sp. SKM2102 for 8 weeks increased the sugar yield to 35.7 and 40.8%, respectively. The best pretreatment conditions in terms of overall sugar yield including a soluble fraction were obtained by ethanolysis after the fugal treatment with Phellinus sp. SKM2102, resulting in production of 42.2 g of total reducing sugars per 100 g of the fungus-pretreated biomass. After the combined pretreatment, simultaneous saccharification and fermentation of the water-insoluble pulp fraction were carried out using Saccharomyces cerevisiae. Ethanol production from undecayed Japanese cedar wood was negligible but pretreatments with the two fungi significantly increased the ethanol production, in combination with ethanolysis. The combined pretreatment with solvolysis and Phellinus sp. SKM2102 is attractive for biorefinery of the recalcitrant softwood.     

Estimating the power and number of microturbines in small-scale combined heat and power systems

Utilizing the combined heat and power (CHP) systems to produce both electricity and heat is growing rapidly due to their high efficiency and low emissions in domestic, commercial, and industrial applications. In the first two categories among available drivers, due to the compact size and low weight, microturbines are attractive choice. In this paper, by using an energy–economic analysis the type and number of the required microturbines for the specific electricity and heat load curves during a year were selected. For performing this task an objective function annual profit (AP) was introduced and maximized. The operation strategy and the payback period of the chosen system was also determined in this study.     

The potential of renewable energy technologies for rural development in Lesotho

The potential and utilization of renewable energy technologies (RETs), and energy analysis in Lesotho with emphasis on the contribution of solar energy technologies (SETs) is presented. The heavy reliance of the country on imported fossil fuel coupled with the growing demand for electricity and declining wood fuel supplies call for alternative sources of energy. Taking the average global solar radiation that ranges from 15 to 20 MJ/m² and cognizant of the short falls of other renewable energy sources in Lesotho, this paper focuses on the application of solar energy and associated developmental issues. The paper provides a statistical analysis of the energy demand and identifies areas of further growth for SETs. Various application areas of solar energy and their contribution to development in Lesotho together with future prospects for use of solar energy are also discussed. An analysis of the relative merits of using photovoltaic (PV) devices over other renewable energy sources in Lesotho is presented. It is argued that with proper economic support and utilization of efficient RETs, developing countries like Lesotho can meet their basic energy demands and alleviate the problems of energy shortages.     

Heat storage for wood drying using solar heat

储热技术有利于提高太阳能的利用率,降低传统木材干燥的能耗,对木材工业的可持续发展具有重要意义。本文系统地阐述了储热技术的基本原理,简要介绍了其应用概况;结合国内外研究现状,分析了储热技术在木材太阳能干燥中的应用,并指出了储热技术在木材太阳能干燥中的发展趋势。     

Trends and driving forces of low-carbon energy technology innovation in China’s industrial sectors from 1998 to 2017: from a regional perspective

Low-carbon energy technology (LC) innovation contributes to both environmental protection and economic development. Using the panel data of 30 provinces/autonomous regions/municipalities in China from 1998 to 2017, this paper constructs a two-layer logarithmic mean Divisia index (LMDI) model to uncover the factors influencing the variation of the innovation of LC in China’s industrial sectors, including the alternative energy production technology (AEPT) and the energy conversation technology (ECT). The results show that China’s industrial LC patent applications rapidly increased after 2005 and AEPT patent applications outweighed ECT patent applications all the time with a gradually narrowing gap. Low-carbon degree played the dominant role in promoting the increase in China’s industrial LC patent applications, followed by the economic scale, R&D (research and development) efficiency, and R&D share. Economic structure contributed to the increases in LC patent applications in the central and the western regions, while led to the decreases in the eastern region, the north-eastern region, and Chinese mainland Xizang(Tibet) Autonoomous Region is not considered due to lack of data. This note applies to the entire article.. Low-carbon degree and economic scale were two main contributors to the growths of both industrial AEPT patent applications and ECT patent applications in Chinese mainland and the four regions. Several policy recommendations are made to further promote industrial innovation in China.     

Biomass Energy and Biochemical Conversion Processing for Fuels and Chemicals

Biomass, mainly in the form of wood, is the oldest form of energy used by humans. Biomass is used to meet a variety of energy needs, including generating electricity, heating homes, fueling vehicles, and providing process heat for industrial facilities. Biomass potential includes wood and animal and plant wastes. Biomass, mainly now represents only 3% of primary energy consumption in industrialized countries. World production of biomass is estimated at 146 billion metric tons a year, mostly wild plant growth. Energy from biomass fuels is used in the electric utility, lumber and wood products, and pulp and paper industries. Biomass conversion may be conducted on two broad pathways: chemical decomposition and biological digestion. The conversion technologies for utilizing biomass can be separated into four basic categories: direct combustion processes, thermochemical processes, biochemical processes, and agrochemical processes. Biological processes are essentially microbic digestion and fermentation.     

Non-electrical uses of Geothermal energy

The non-electric applications of geothermal energy, with the exception of balneology, date back to the nineteenth century and have been given a new impetus by the recent oil crisis.In general, water or water-steam mixtures at temperatures between 20 and 180°C are used for these applications.The search for geothermal fluids draws on techniques from hydrogeology, geochemistry and geophysics, the same techniques as applied to the search for cold waters, together with some specific methods connected with the underground thermal conditions.Geothermal energy is used in agriculture, aquaculture, district heating and cooling and various industrial applications. The power associated with these uses throughout the world at present can be estimated at 6200 MW and future prospects are by now promising and of definite economic interest.The environmental impact from geothermal energy is lower than that caused by conventional energy sources. Reinjection of used fluids back into the underground may, however, solve pollution problems.     

Main routes for the thermo-conversion of biomass into fuels and chemicals. Part 1: Pyrolysis systems

Since the energy crises of the 1970s, many countries have become interest in biomass as a fuel source to expand the development of domestic and renewable energy sources and reduce the environmental impacts of energy production. Biomass is used to meet a variety of energy needs, including generating electricity, heating homes, fueling vehicles and providing process heat for industrial facilities. The methods available for energy production from biomass can be divided into two main categories: thermo-chemical and biological conversion routes. There are several thermo-chemical routes for biomass-based energy production, such as direct combustion, liquefaction, pyrolysis, supercritical water extraction, gasification, air–steam gasification and so on. The pyrolysis is thermal degradation of biomass by heat in the absence of oxygen, which results in the production of charcoal (solid), bio-oil (liquid), and fuel gas products. Pyrolysis liquid is referred to in the literature by terms such as pyrolysis oil, bio-oil, bio-crude oil, bio-fuel oil, wood liquid, wood oil, liquid smoke, wood distillates, pyroligneous tar, and pyroligneous acid. Bio-oil can be used as a fuel in boilers, diesel engines or gas turbines for heat and electricity generation.     

Passive solar agricultural greenhouses: A worldwide classification and evaluation of technologies and systems used for heating purposes

Results from a recently completed study of 95 solar greenhouses from around the world, representing the state-of-the-art in this field, are presented and are classified. Relevant technical information on the utilised heating systems using alternative energy sources are identified and the existing applications are grouped according to the characteristics of the implemented type of technology. Five categories of passive solar greenhouses are reviewed, according to the characteristics of the heat storage system, namely, water, latent heat material, rock bed, buried pipes, and some other type of systems. Available information on the performance of each system is also included. The suitability of the technologies for each climatic zone and type of cultivation is estimated and evaluated. This up-to-date information on the state of the art in this field can be of great importance to potential users for the successful development of future applications.     

Pellets 2002: the first world conference on pellets

Large-scale implementation of wood pellets as a solid biomass fuel represents a change in the energy system that will have both economic and environmental consequences. This article represents a summary of a state of the art conference, which was organised in Sweden in September 2002. The aim was to bring together people to create a network where industry, research, other expertise and decision makers meet to build a strong pellet industry for the future. The sum of the economic, technological and environmental evidence presented at this conference weighs very heavily in favour of the pellet option.