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THERMAL DECOMPOSITION OF SOLID BIOFUELS AND ASSOCIATED FINE PARTICLE GENERATION
Sitek, Tomáš ; Ličbinský, Roman (referee) ; Svěrák, Tomáš (referee) ; Pospíšil, Jiří (advisor)
Despite otherwise indisputable advantages, biomass burning is associated with significant emissions of fine particles. The different behavior of dissimilar types of biomass during thermal decomposition can be explained to some extent by the different composition, i.e. the different content of cellulose, hemicellulose and lignin. The main aim of this work was to find the emission characteristics of these three components during heating in a thermogravimetric analyzer. The monitored parameters were the heating rate and the oxygen content in the combustion atmosphere. The output is the dependence of the sample mass and also the corresponding distributions of particles on the temperature. The results show considerable differences between the individual samples, but in general the pyrolysis of cellulose produces the highest particle emissions. Higher oxygen content in the combustion atmosphere and lower heating rates cause earlier sample decomposition and reduce particulate emissions. This is followed by an evaluation of the transferability to a sample of a real biomass based on its known composition using a simple weighted arithmetic mean. Useful information on particle sampling and electron microscope visualization, supplemented by images of particles from the pyrolysis of selected samples can also be found in this work.
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Anisokinetic dust sampling
Šenk, Daniel ; Zlevorová, Tereza (referee) ; Lachman, Jakub (advisor)
The presented thesis deals with the determination of the concentration of dust particles released during the operation of combustion boilers. The accuracy of these measurements can be affected by a number of factors. One of the main factors is the ratio between the gas velocity in the sampling probe and the gas velocity in the pipe. If this ratio is different from 1, we speak of so-called anisokinetic sampling. The CSN standards for the boilers in question prescribe limits for deviations from this value. For automatic biomass boilers, an allowable range is from 0.70 to 1.50. For values within this range, the mass concentrations of dust particles during the combustion of wood and sunflower pellets were determined by manual gravimetric method. The mass concentrations were then converted to relative measurement errors compared to reference values under isokinetic conditions. For the lower limit deviation, a relative measurement error of up to 22.9 % was determined. In the upper range, deviations from the reference values are up to 39.7 %. In this range, an underestimation of the concentration of dust particles occurs; therefore, it would be advisable to consider lowering the upper limit of the permissible isokinetic ratio in the CSN.
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Dispersion of particulate matter pollution from electric vehicles in urban areas using CFD
Lipka, Jakub ; Pospíšil, Jiří (referee) ; Linda, Jakub (advisor)
There is an opinion across the society, that electric vehicles (EV) are emission-free alternative to vehicles using internal combustion engines (ICEV). This is not true. Although electric vehicles do not produce emissions connected to internal combustion, they still produce non-combustion emissions that are emitted into surrounding air. Non-combustion emissions in question are brake wear particles (BWP), tire wear particles (TWP) and road wear particles (RWP). These emissions, due to EV’s greater mass, tend to be higher compared to ICEVs. Therefore, in this thesis, model of dispersion of non-combustion emissions generated by EVs was created using CFD consisting of two models – airflow model around EV and particle dispersion model. It was found that those emissions are captured and distributed by airflow, mainly thanks to vortices generated in the wake zone behind the vehicle. Those particles can be suspended up to 1,9 m into the air and up to 2,5 m laterally away from the vehicle. Thanks to that there is a risk of pedestrian inhaling air with high concentration of those particles in places near roads like pavements.
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Studium složení emitovaných pevných částic z domácího spalování
Lesná, Barbora ; Mravcová, Ludmila (referee) ; Doležalová Weissmannová, Helena (advisor)
The aim of this bachelor thesis is the analysis of the chemical composition of different biomass samples. Biomass samples underwent combustion in a fireplace stove, simulating combustion in domestic fireplaces. Firstly, biofuels are defined and the difference in chemical composition between wood and herbal fuels, which this thesis focuses on, is being discussed. In the following chapters, the combustion process and various types of emissions being released from the combustion of solid fuels are presented. Attention is paid to legislation and methods of measuring aerosols, then the focus is drawn to methods of their chemical analysis. The last chapters of the theoretical part focus on the health and environmental risks of solid particles that go hand in hand with being exposed to those particles. In the experimental part, the processes of sampling filters with particles, microwave decomposition of the samples. Furthermore, the thesis describes the analysis of the chemical composition of the input fuel, emitted particles and ash, in which metals were determined by the method of absorption atomic spectrometry. The concentration of solid particles on the filter is calculated here. In the discussion, individual fuels are compared according to the content of each metal.
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Spatio-temporal distribution of atmospheric aerosol in urban and rural environment
Bendl, Jan
Air quality in Europe remains a significant environmental concern, affecting the health and quality of life of its population. While stationary network ambient air quality monitoring allows for the observation of main trends, it is not fully representative of personal exposure of citizens due to high spatio-temporal variability of atmospheric aerosol. Therefore, highly time-and- space resolved measurements with state-of-the-art instruments and methods are needed to observe the aerosol variability, dynamics, identify hot-spots, and pollution sources, which are necessary for successful targeted mitigation measures. This thesis addresses this gap focusing on the characterization of spatio-temporal distribution of atmospheric aerosol in inhabited environments. Novel mobile measurement systems were developed and employed to investigate diverse environments, including rural, urban and suburban area. Aerosol source-apportionment were conducted, and the toxicological effects associated with these environments were also investigated. A novel mobile measurement system was developed for personal exposure measurements and pollution mapping in urban and rural environments. The system was used to measure air quality in the Munich subway, revealing high aerosol dynamics with significantly higher concentrations of...
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Influence of polymers to reduce dust
Šubrt, Michal ; Mravcová, Ludmila (referee) ; Vávrová, Milada (advisor)
The main issue this bachelor thesis deals with the reduction of emit into the enviroment. A specific type of polymer compound from Canadian provenance will be tested for this purpose. The aim of this work will be the identification of positive characteristics of the polymer, and determine to the appropriate method of application. The above mentioned reduction of dust, stabilization of areas after application, possibly reduction of its permeability and increase of its maximum dry density will also by measured.
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Design of a filter unit for waste gas cleaning
Volánka, Lukáš ; Wegschmied, Roman (referee) ; Jecha, David (advisor)
This bachelor's thesis focuses on the design of the filtration unit and on particulate matter, or PM, which is still a significant contributor to air pollution. The first chapter describes the basic properties of these pollutants and their influence on the design of the separator. The next chapter briefly discusses the current legislation in the Czech Republic dealing with emission and air pollution limits. In the third chapter, which is also the last of the theoretical part of the thesis, the individual methods of removal of PMs are presented and explained. The practical part follows, mainly devoted to the design of the filtration unit for the given case, which ends with the measurement of emissions and a brief evaluation of the results.
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The concentration of particulate matter in the air of selected areas of the city of Brno and its health risks
Bulejko, Pavel ; Čáslavský,, Josef (referee) ; Adamec, Vladimír (advisor)
Tato práce se zabývá znečištěním ovzduší pevnými prachovými částicemi v lokalitách města Brna. V teoretické části je pojednáno o možných zdrojích prachových částic, o chemickém složení a velikostní klasifikaci polétavých částic a dalších fyzikálně-chemických charakteristikách. Další část je věnována zdravotním rizikům prašnosti. V této souvislosti práce pojednává o anatomii dýchacího systému a účincích prachu na něj. Jsou taktéž rozebrány zdravotní efekty prachového znečištění, včetně uvedení možných nemocí respiračního a kardiovaskulárního systému, jejichž může být prach příčinou. V praktické části byl proveden sběr prachu. Byly vybrány celkem čtyři lokality, kde byly prováděny odběry vzorků. Následně byly stanoveny koncentrace polétavých částic PM10 a PM2,5. Dále byly u vybraných lokalit stanoveny koncentrace těžkých kovů a polyaromatických uhlovodíků vázaných na prachových částicích. V závěru bylo provedeno srovnání s legislativou a stanovena zdravotní rizika.
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