Modelovanie tvorby emisií malého zdroja tepla na spaľovanie uhlia

The aim of the work is to develop a method of simple characterization of solid fuels combustion in fixed bed, which would be useful for CFD modelling. In this work, the measurements were performed in a test rig, where a combustion front propagates against the airflow. Concentrations of flue gas species were registered at the exit of a fixed bed reactor and the temperature of burning coal was measured in selected points of the reactor as functions of time.Cieľom práce je vyvinuť metódu charakterizujúcu spaľovanie tuhého paliva na rošte, ktorá môže byť použitá pre matematické modelovanie. Práca pozostáva zo štyroch úloh: experimentálne merania zamerané na spaľovanie uhlia v reaktore s pevným roštom, spracovanie nameraných hodnôt do formy funkcií, matematické modelovanie v CFD a verifikácia modelu pomocou meraní vykonaných na kotle o výkone 25kW

Waste-to-energy technology integrated with carbon capture – Challenges and opportunities

Carbon dioxide emission is a serious environmental issue that humankind must face soon. One of the promising technologies for reducing global CO2 emissions is oxy-fuel combustion (OFC) technology, which belongs to the carbon capture methods. OFC involves the use of oxygen and recirculated flue gas as an oxidizer in the combustion process. Application of oxy-fuel combustion in waste incineration can result in negative CO2 emission since some part of the carbon in municipal solid waste is biogenic. Such technology is often described as BECCS or Bio-CCS and it has attracted the attention of scientists recently. In addition to easier CO2 capture, oxy-fuel combustion of municipal solid waste offers other advantages, such as reduced flue gas volume, increased combustion temperature and the possibility of retrofit existing incineration plants. In the present paper, studies of oxy-fuel combustion of waste materials, in particular, municipal solid waste and sewage sludge are presented and summarized. The study shows the opportunities and challenges that have to be addressed to fully exploit the potential of the oxy-fired incineration plant.publishedVersio

Numerical Modelling of Emission Formation in Domestic Boiler for Coal

The aim of the work is to develop a method of simple haracterization of solid fuels combustion in fixed bed, which would be useful for CFD modelling. In this work, the measurements were performed in a test rig, where a combustion front propagates against the airflow. Concentrations of flue gas species were registered at the exit of a fixed bed reactor and the temperature of burning coal was measured in selected points of the reactor as functions of time

A comparative study on thermochemical decomposition of lignocellulosic materials for energy recovery from waste: Monitoring of evolved gases, thermogravimetric, kinetic and surface analyses of produced chars

Increased waste generation caused by the growth of urbanisation rate forces scientists and policymakers to rapidly develop and implement optimal waste management strategies. Since there are many ways to waste treatment and each waste material has different physicochemical properties, they should be investigated separately. This paper presents the results of an experimental investigation on the thermal decomposition of the spent coffee grounds (SCG) and textiles under various atmospheres using a vertical tube furnace. In the study, different analytical techniques are used, such as gas chromatography (GC), gas adsorption for surface area and porosity determination, Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Results indicated that SCG sample yielded more calorific pyrolytic gas (209.8 kJ/mol). than TEX (198.7 kJ/mol). O2/CO2 atmosphere fasten the fuel decomposition. Concerning biochar, it can be concluded that fast pyrolysis influenced their combustion performance, for example, its ignition temperature, TEX_slow (475.4 °C) > SGS_slow (470.5 °C) and TEX_fast (469.6 °C) > SGS_fast (415.0 °C), maximum weight loss rates and reactivity. This study will provide a better understanding of thermochemical degradation of waste and allows for developing optimal routes of waste utilisation. © 2023 Elsevier Ltd Author keywords Char; Gasification; Municipal solid waste; Oxy-fuel combustion; Pyrolysis; Waste-to-energyacceptedVersio

Numerical Study of Hydrogen Inhibition of Char Gasification Using Detailed Hetero- and Homogeneous Chemical Kinetics

It has been known for a long time that hydrogen in the gas phase tends to inhibit gasification of char at low and intermediate temperatures. At higher temperatures, however, there are indications that hydrogen may speed up gasification. The mechanisms behind these effects are currently not understood. In this work, a newly developed detailed chemical kinetics model for char has been used to study the mechanisms behind the hydrogen inhibition and speed up of char gasification. For conditions assumed in this work, the hydrogen inhibition is found for T 2000 K, hydrogen in the gas phase speeds up the char conversion. By studying the species reaction rates together with the individual rate of every heterogeneous reaction, the reasons for hydrogen influence on char gasification are attempted to be explained for a wide range of different temperatures in this paper. The focus is not on investigating a real gasifier but rather to understand the fundamental mechanism behind hydrogen inhibition of char