Výzkum environmentálních vlastností pelet.

Abstract

My dissertation is focused on the study of physical-mechanical properties of materials and their impact on the production of pellets. Pelletization was predominantly oriented on biomass (energetic grasses from Oseva Pro, Zubří), compost and the product of pyrolysis „pyrolysis char“ which based on its qualitative parameters (content of inorganic component) can be used as a fuel only. While studying the physical-mechanical properties the following parameters were studied: grain composition, durability (Durability Index-PDI), compression resistence (hardness) and water resistence „wettability index“ (WI). The effect of ash content in some materials and the effect of the content of the majority component (particularly lignin) in biomass on mechanical properties of pellets was monitored. From the point of view of the optimalisation of mechanical properties of pellets, the effeft of adding various binding agents and humidity was monitored. Pelletization which is one of the forms of densification has become a more and more widely used method of material treatment. Energetic utilization of biomass is the most commonly used application of densification. Biomass represents a renewable source of energy, which has the potential to cover a certain percentage of the world’s energy consumption.Other possibilities for the utilization include the pelletization of waste products. Recently there has been progress in the composting of biologically degradable components of waste. Composts which do not have the qualitative parameters for agricultural application or recultivation do have the potential for energetic utilization. Compost pellets represents a convenient form of transport material. Moreover, pelletization opens up to the possibility for the addition of supplement materials with high content of carbon, these will replace carbon losses caused by the composting process which could be 20 – 40 %. In terms of the physical - mechanical properties and grain size composition, pellets made on the base of coal sludge (sludge lagoon Nový York) and compost, lignite (Chomutov coal basin) and compost, or compost with waste carton were tested. Based on the pellet durability index value it has been proven that sufficiently durable pellets are made from compost and coal, where coal content is not more than 30 % and less than 10 %. These pellets also have the lowest Wettability index. Composts, which comply with Czech regulation 341/2008 Sb. „About Biowastes“, can be pelletised for fertilizer. Although this aplication is more energy demanding than direct use of compost, with this method it is posible to better regulate the fertiliser dosage, alternatively we can increase the content of nutrients or utilize aditives for the improvement of the fertilizer´s properties (controlled release of nutrients-addition of betonit). Durability of compost pellets is between 89 – 97 % and water resistance expressed as wettability index is between 8 – 29 %. With projected expansion of pyrolysis there will be increased production of pyrolysis char which will need to be dealt with. One of the possible applications of this char is to use this material for the production of pellets. Only pure pyrolysis char or pyrolysis char in mixture with additives which are improving the pellets properties can be processed. Pellets made from pure pyrolysis char have lower durability, fluctuating between 68% for pellets...