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Low-NOx technologies are widely used in pulverized coal boilers, but they usually produce high levels of carbon in the fly ash. High levels of unburned carbon represent fuel loss, so the overall boiler efficiency is reduced. Additionally, the higher carbon content affects the suitability of fly ash for cement applications. The purpose of this paper is to provide a CFD approach for unburned carbon reduction by optimizing operating conditions. In this paper, three different boiler loads were simulated: 200 MW, 170 MW, and 140 MW. The air supply system was simulated previously for preparing as precise as possible boundary conditions. At last, unburned carbon level of every burner was investigated, and the effects of residue residence time and the local fuel-air momentum ratio are discussed in detail. According to the predicted results, operating conditions and the residence time of the coal particles affects the unburned carbon level in fly ash. Operating conditions plays a more significant role during the combustion process, while the residence time affects char burnout only when the burner's location is low. Therefore, it is concluded that a cost effective method could be developed for reducing the unburned carbon level in ash and correspondingly, the loss on ignition level. First, it is necessary to determine which burners are operating under poor conditions through CFD analysis. Then, the fuel air momentum ratios of those burners should be modified by changing the operating conditions, meanwhile, increasing residence time of coal particles to ensure complete combustion.

Alpha-1-antitrypsin is a potent antiprotease playing an important role in maintaining protease-antiprotease balance. It protects the structures of extracellular matrix against destruction by proteolytic enzymes. Loss of elasticity occurs when increased protease activity is accompanied by qualitative impairment or reduced concentrations of antiproteases. Alpha-1-antitrypsin deficiency is a risk factor for obstructive lung disease, including emphysema, liver and kidney disorders and, less often, follicular panniculitis, granulomatosis with polyangiitis (previously Wegener's granulomatosis). Literature also emphasises the role of AAT in the development of aortic aneurysms, and results of biochemical studies support this theory. Aortic aneurysm is an important clinical problem, unceasingly associated with high mortality. For this reason, it is exceptionally important to identify its risk factors. Studies on the relationship between AAT and development of AAA (abdominal aortic aneurysm) have been conducted since the 1990s. Due to the development in molecular diagnostic techniques, new reports on the topic appeared over the last decade.

This paper presents numerical study on the combustion performance and NO x emissions of a 220 MW pulverized coal boiler. Three different loads have been simulated with combusting coal, 200, 170 and 140 MW, respectively. In order to get as precise as possible numerical analysis results, two-step simulation method has been adopted in this work, namely, air supply system simulation and furnace simulation. After air supply system simulation, the results have been taken as the initial and boundary conditions for furnace simulation. The comparison between the measured values and predicted results from 200 MW case shows much better agreement. According to the simulation results, the adopted two-step simulation method is reasonable and suitable for predicting the characters of the flow and combustion process. It is concluded that the distributions of temperature, O 2 and CO concentration inside furnace with different loads shows good similarly. The total NO x emissions decreased with the boiler load reducing, and fuel NO x has the same trend as total NO x , and fuel NO x account for about 66% in total NO x in all the three cases. More important, thermal NO x slowly decreased with the rise of boiler load. More detailed results presented in this paper enhance the understanding of combustion processes and complex flow patterns of front-wall pulverized coal boilers.

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STRESZCZENIE W artykule przedstawiono zmienność sezonową biomasy i składu gatunkowego glonów planktonowych w nowopowstałym zbiorniku zaporowym Wilkówka w Wilkowicach. Dodatkowo zaprezentowano zmienność sezonową stężeń chlorofilu a. Badania były prowadzone w 2014 roku w obrębie dwóch stanowisk badawczych (na dopływie rzeki Wilkówki do zbiornika oraz w rejonie zapory). Wartości biomasy fitoplanktonu oraz koncentracje chlorofilu a były niskie, z kolei w strukturze gatunkowej fitoplanktonu dominowały okrzemki oraz kryptofity.