Woody biomass is an abundant, renewable energy source. Forest residue is the fraction remaining after harvest and the outtake of wood timber, including tree tops and bark. Compared with the wood portion, bark has a wide variation of ash content. Wood usually has a relatively low ash content, while bark has considerably higher ash content, which may generate clinker in the furnace and thereby tends to create more demand for maintenance. High ash content also generates more particulate emissions. Different types of bark were studied in the present work in terms of their effect on energy content, moisture, and ash content. The ash content of three different samples (Norway spruce, birch, and European beech) were measured at 550 and 815 °C. The results showed the impact of bark content on all parameters, in particular the calorific value and ash content. The ash content increased with increasing bark content. The addition of 1% bark content resulted in increases of ash content in the range 0.033 to 0.044%.

Constant effort to reduce heating costs leads to production of not only high-quality pellets from pure wood but also cheaper vegetable pellets of inferior quality in terms of energy properties. , The combustion of alternative pellets in small boilers causes many problems, mainly ash sintering, as a result of their low melting temperature. , The paper focuses on experimental determination of bed temperatures in the burning layer during wood pellet combustion. The bed temperatures are important for prediction of combustion phases and better localization and description of sites that are critical for the sintering of ash particles as temperatures are close to the ash melting points. This experiment describes a method for measurement of the temperature field in the symmetry plane of the burner during wood pellet combustion in the retort burner. The measurement of temperature profiles at different locations in the burner shows that the combustion process in the retort burner is rather more horizontally stratified than vertically stratified. The main combustion process takes place in a ring-shaped space around combustion air inlets.

This paper deals with the pyrolysis conversion of synthetic waste materials into noble fuels, i.e., heating oils, gasoline, diesel, and carbon. The following article presents the principle and use of pyrolysis conversion of waste tires and plastics. The core of the paper is the determination of energy properties of noble fuels obtained from pyrolysis conversion and the possibility of their real use in industry. The aim of this paper is a technical-economic evaluation of the use of waste pyrolysis in practice in the Slovak Republic. Unlike various methods of waste management, there are also more efficient methods, which primarily have a positive effect on the ecology of our Earth and at the same time can be effectively used for the production of alternative fuels. One of these methods is the pyrolysis conversion of synthetic waste materials into noble fuels. It is an ecological, waste-free, economical, and economical disposal of waste with a full recovery of its energy and material components with reduced emissions, and therefore this direction of using synthetic waste for the conversion of alternative fuels contributes to sustainable development. A significant advantage of this waste management is considered to be the fact that only waste tires or chlorine-free plastics are used as input materials without other necessary raw materials obtained by other economic activity. Tires and plastics are generated daily as waste in every household.

No abstract

Abstract. Biofuels are more and more popular energy source and they are used in more households in the Eastern Europe region. Straw from the agriculture crops is promising and significant biomass source of energy but now it is at least energy utilized. In terms of straw burning is the most important feature of its quick and easy volatilization. Another property, which is negative, is its low ash fusion temperature. The straw ash begin soften at about 830 °C. However, at the temperature 850 °C to 900 °C the ash transform to glass slags and sinters which damage the refractory of the furnace and it is also difficult to remove. The paper deals about the option for reducing the problems of low ash fusion temperature by additives application. The presented results are from the lime application in the laboratory conditions and in the real conditions, in the heat source with the nominal thermal power 2 MW. The results of the experiments showed that the results from the real operation does not correspond with laboratory results.