Bioenergy Conversion Potential of Decaying Hardwoods

Using Timber as a Renewable Resource for Energy Production in Sustainable Forest Management

Using timber from multifunctional forests for energy production can be economically viable and environmentally friendly when it is consistent with the principles of sustainable management; otherwise, it could be harmful from both an ecological and commercial point of view. The objective of this paper was to present the overall balance of timber biomass from felled trees in multifunctional forests and assess what kind and how much of this biomass can be used for energy purposes. The research material consisted of data on forest resources and the volume of timber removal in Polish State Forests in 2016–2020. The biomass of branches and stumps of felled trees was determined using biomass expansion factors (BEFs). The results obtained in this study indicated that industrial timber, energy wood, and biomass left in the forest as a source of deadwood are 67%, 20%, and 13% of the total woody biomass, respectively. The Polish State Forest’s potential for energy wood is estimated at 6.18 million tonnes of biomass annually. Total available energy produced from woody biomass amounted to 104.8 PJ y−1.

Potential of Forest Biomass Resources for Renewable Energy Production in the Czech Republic

In the European Green Deal and the Climate Act, the European Union has committed itself to achieving climate neutrality by 2050. This goal is to be achieved by joint efforts of all economic sectors, including forestry and its downstream sectors. One way to attain this goal is the effective and sustainable use of forest biomass for energy production. This article aims to quantify the potential of forest biomass resources for the production of electrical and thermal energy based on official departmental statistics, the current legal framework for forestry and the environment, and research results in the context of an extreme change in the raw material base due to the ongoing calamity caused by the spread of insect pests in the Czech Republic. This extreme can classify as a significant risk to the security of the energy supply from renewable sources in the event of oversizing new installed energy production from renewable sources. Based on data and calculations, an overall annual volume of dendromass available for energy production in the Czech Republic for the period extending to 2036 was quantified at the value of 13.473 million tons per year. Consequently, it is clear that the overall dendromass resources for energy production in the Czech Republic are not sufficient to achieve the EU’s ambitious objective.

Experimental Analysis of Temperature Influence on Waste Tire Pyrolysis

Pyrolysis is an optimal thermochemical process for obtaining valuable products (char, oil, and gas) from waste tires. The preliminary research was done on the three groups of samples acquired by cutting the same waste tire of a passenger vehicle into cylindrical granules with a base diameter of 3, 7, and 11 mm. Each batch weighed 10 g. The heating rate was 14 °C/min, and the final pyrolysis temperature was 750 °C, with 90 s residence time. After the pyrolysis product yields were determined for all of the three sample groups, further research was performed only on 3 mm granules, with the same heating rate, but with altered final pyrolytic temperatures (400, 450, 500, 550, 600, 650, 700, and 750 °C). The results of this study show that thermochemical decomposition of the waste tire sample takes place in the temperature range of 200–500 °C, with three distinct phases of degradation. The highest yield of the pyrolytic oil was achieved at a temperature of 500 °C, but further heating of volatile matters reduced the oil yield, and simultaneously increased the yield of gas, due to the existence of secondary cracking reactions. The analysis of pyrolytic oil and char showed that these products can be used as fuel.