Janis Abolins

Utilization of lignin powder for manufacturing self-binding HDF

Abstract The preparation of self-binding lignocellulosic fibreboards has been investigated. Different high-density fibreboards (HDF) were hot-pressed based on a mixture of grey alder (Alnus incana L. Moench) wood chips processed by steam explosion auto-hydrolysis (SE) and 15% or 25% lignin content from three different industrial sources: softwood kraft lignin (SWKL), soda wheat straw lignin (SoWhStL) and hydrolysis wheat straw lignin (HWhStL). Density, thickness swelling (TS) after immersion in water for 24 h, modulus of rupture (MOR), modulus of elasticity (MOE) and strength of internal bond (IB) of the board samples were determined. The amount (15% or 25%) and moisture content (MC) (18±1% or 5±2%) of the added lignin affected all the tested properties of the HDF except for density. However, the kind of the added lignin affects the obtained fibreboard more significantly compared to the control sample made without an admixture of lignin. In some cases, the tested values were diminished to half. The tested properties of the HDF samples produced with SoWhStL or HWhStL are compatible with standard requirements for medium-density fibreboard (MDF) for general use under dry conditions (EN 622-5, MDF), however, it depends on the lignin amount and MC.

A Simple Analytical Model for Remote Assessment of the Dynamics of Biomass Accumulation

Efficient means for assessment of the dynamics and the state of the stocks of renewable assets such as wood biomass are important for sustainable supplies satisfying current needs. So far attention has been paid mainly to the economic aspects of forest management while ecological problems are rising with the expected transfer from fossil to renewable resources supplies of which from forest being essential for traditional consumers of wood and for emerging biorefineries. Production of biomass is more reliant on assets other than money the land (territory) available and suitable for the purpose being the first in the number. Studies of the ecological impacts (the “footprint”) of sustainable use of biomass as the source of renewable energy encounter problems associated with the productivity of forest lands assigned to provide a certain annual yield of wood required by current demand for primary energy along with other needs. Apart from a number of factors determining the productivity of forest stands, efficiency of land-use concomitant with growing forest depends on the time and way of harvesting (Thornley & Cannell, 2000). In the case of clear-cut felling the maximum yield of biomass per unit area is reached at the time of maximum of the mean annual increment (Brack & Wood, 1998; Mason, 2008). The current annual increment (rate of biomass accumulation by a forest stand or rate of growth) culminates before the mean annual increment reaches its peak value and there is a strong correlation between the maximums of the two measures. Knowing the time of growth-rate maximum (inflection point on a logistic growth curve) allows predicting the time of maximum yield (Brack & Wood, 1998). However, the growthrate maximum is not available from field measurements directly. Despite the progress in development of sophisticated models simulating (Cournede, P. et al., 2009; Thurig, E. et al., 2005; Welham et al., 2001) and predicting (Waring et al., 2010; Landsberg & Sands, 2010) forest growth, there still remains, as mentioned by J. K. Vanclay, a strong demand for models to explore harvesting and management options based on a few available parameters without involving large amounts of data (Vanclay, 2010). The self-consistent analytical model described here is an attempt to determine the best age for harvesting wood biomass by providing a simple analytical growth function on the basis of a few general assumptions linking the biomass accumulation with the canopy absorbing

Ecological Limits to Sustainable Use of Wood Fuels

A theoretical study of a simple analytical model of biomass accumulation to assess conditions of the neutrality of CO2-emissions from burning wood (biomass) is reported. Conditions under sustainability defined with respect to harvesting are shown to satisfy requirements of CO2-neutrality on local scale while burning wood under conditions of shrinking global forest area is not and should be taken into account in the balance of global emissions. Other ecological restraints—conservation of biodiversity in particular, are discussed concerning conditions imposed by the economic system and reflecting on the visions of bio-economy.

Biomass conversion into blow-in heat insulation materials by steam explosion

Abstract The study of converting grey alder (Alnus incana) chips and silver birch (Betula pendula) flakes – residues from plywood manufacture – into blow-in insulation material by steam explosion (SE) is reported. The SE was conducted at temperatures between 200 and 235°C, for 0–5 min at pressures between 16 and 32 MPa. The severity parameters (logR0) of the SE was calculated, from which logR0≈3.6 was the most appropriate for production of blow-in materials. Thermal conductivity of the obtained insulating material was found to be in the range of 0.053–0.057 W m−1·K−1.

Zero Emissions and Bio-refineries for Natural Fibres, Biomaterials and Energy: Genesis of Concepts. Review

Depletion of world recourses, increasing pollution, and climate change make us to shift from linear economy to system economy—an economy of technologies integrated to reach a system of non-polluting zero emissions production. Transition to renewable resources requires replacing the present crude oil refinery by biomass refinery. Along with conventional biomass refinery technologies bioengineering and nano-technologies become significant players in systems designed as clusters of integrated bio-refinery technologies. The authors consider a number of case studies of biomass conversion into value-added chemicals and sources of energy, the steam explosion auto-hydrolysis (SEA) in particular. Research of wood and non-wood (hemp, etc.) fibres demonstrates feasibility, for example, of value added textiles, self-binding bio-composite boards, heat insulating micro- and nano-materials. Serious breakthroughs require revision of the structures of fundamental natural macromolecules, particularly the complexity, scaling and fractality of lignin.

Limits to Sustainable Use of Wood Biomass

Amounts of wood biomass from fast-growing forest stands are assessed with respect to maximum land productivity and with account for the capacity of photosynthesis. The results expressed in normalised coordinates of time and stock in general are relevant to any even-age stand. By comparing the energy densities of solar radiation transformed by photosynthesis and photovoltaic devices the authors argue that generating electricity by burning wood is an extremely inefficient use of land under conditions of sustainable supply of the fuel and conclude that transfer to bio-energy without radical changes in the existing economic system would further aggravate the environmental crisis.

Graduate Studies of Global Change at the University of Latvia

In 2008 the University of Latvia (UL) completed an 18-month project of innovation – design, preparation and pilot-test of a 4-semester programme of trans-disciplinary graduate studies in “science, global change, and technologies for sustainable development” based on the experience the project team had acquired during 1997–2006 endorsing studies in “physics and technologies for sustainable development” and organizing two international conferences on “integrative approaches towards sustainability”. Within the project activities 25 members from faculties of natural sciences of the UL prepared and tested innovative courses of a 2 semester pilot programme comprising 4 modules, the audience being a multidisciplinary group of graduates and postgraduates. The 4 modules included geophysics, biophysics, environmental physics, chemistry, global change, closed production cycles and other technologies, corporate responsibility, and research methods. The paper provides details of information and knowledge on climate change considered within the programme, experience acquired during the project activities, and future prospects including the mission of the project team in raising the general publics awareness about the science of climate change. For the long-term efforts, the project team was awarded the national prize of ENERGY GLOBE 2007 on sustainability in the category “YOUTH” by the EU Parliament in Brussels on 26 May 2008.