High mercury emission (both forms: Hg0 and Hg2+) from the wet scrubber in a full-scale lignite-fired power plant

The paper describes and discusses the results of research on mercury behaviour, especially its high emission, in both forms: elemental (Hg-0) and oxidised (Hg2+) from the wet flue gas desulphurisation scrubber (WFGD) in a lignite-fired power plant located in central Europe. The presented results involve the collection of lignite power plant samples (liquid, solid, gas) and different laboratory chemical analyses to try to understand the mechanism of mercury re-emission from the wet flue gas desulfurization system. It was noted that 67-80% of the total inlet mercury concentration left the WFGD scrubber. Moreover, the oxidised form of mercury was the main emitted form (about 60-70% of the total mercury concentration). The results show that mercury was found in very high concentration (10 mu g/g) (range: ppm) in the WFGD solid by-products, whereas the liquid phase contained only 1 mu g//l (range: ppb). Considering literature reports and presented data from the investigated power station, we believe that iron (Fe), which occurs in very high concentrations in solid WFGD samples (1.81% wt. Fe) and lignite (up to 20 g/kg Fe) is mainly responsible for disrupting the mercury absorption in the scrubber, the partitioning of the mercury between phases and leads to its reemission. Moreover, we believe also that a relatively high iodine ion concentration (130 mg/l) in the limestone slurry leads to mercury emission in its oxidised form, mainly as Hgl(2), which is highly volatile. Other minor components from limestone dissolution such as Mn, Al and Mg may additionally enhance that "complex" mercury behaviour.Web of Science270art. no. 11749

NO2 pollution of the atmosphere and the influence of industrial processes

Among nitrogen oxides in atmosphere, the concentration of N2O is the highest (about 306 ppm) and due to the high global warming potential (GWP = 320) nitrous oxide belongs to important greenhouse gases. Moreover, N2O contributes also to the ozone layer depletion. Nitrous oxide is produced by both natural processes and anthropogenic activities, where combustion plays an important role. Two analytical methods ( IR spectrophotometry and gas chromatography) have been used for the analysis of N2O emissions from various industrial sources. Carbon monooxide at the concentration above 500 ppm interferes the IR analysis. The emission factors for combustion processes typical for Czech Republic have been calculated. Emission concentrations depend on the type of the combustion process (the highest is for the fluid-bed combustion) as well as on the output of the combustion unit. In an identical unit, the emission factor increases when the output decreases. A high concentration of nitrous oxide have been found in emissions from the chemical industry where catalytic denitrification is used

Influence of RDF composition on mercury release during thermal pretreatment

The growing world population is contributing to the increasing amounts of waste and a significant increase in energy demand. Therefore, coal will increasingly be replaced by refuse derived fuel (RDF), which is produced from municipal solid waste. The use of such fuel poses many difficulties because of its heterogeneity and high mercury emission. One method to stabilize the properties of RDF and reduce the mercury content is thermal pretreatment. The purpose of this study was to investigate the release of mercury from RDF samples following thermal pretreatment. The study was carried out in the temperature range of 100–350 ◦C. Statistical analysis was performed on the correlation between the composition of the RDF samples and the release of mercury. The RDF samples showed a very high variation in the mercury content, ranging from 45 to 849 µg Hg/kg (1.7 to 35.3 µg Hg/MJ). Thermal pretreatment removed a significant amount of mercury at 250 ◦C (94–99%). Paper content positively affected mercury release. Relatively low correlation coefficients were obtained in the statistical analysis, which may be explained by the significant heterogeneity of the RDF samples magnified by the variability in the mercury content within particular fractions.Web of Science162art. no. 77

N2O EMISSIONS FROM THE MOBILE SOURCES

Nitrous oxide (N2O) generally known for its anesthetic and hallucinogenic properties is oxide with the lowest valence of nitrogen among other oxides of nitrogen. In addition, it is the most stable nitrogen oxide in the environment. Measurement of the N2O emissions from the mobile sources has recently come forward and there are only few data at disposal. Due this reason we make described experiment

The methods and stands for testing fixed sorbent and sorbent polymer composite materials for the removal of mercury from flue gases

The most common methods of reducing mercury emissions are the use of fixed bed granular sorbents and sorbent injection. However, both of these methods have disadvantages, such as increasing the flow resistance or the need to remove the sorbent from flue gas, respectively. These disadvantages can be eliminated by using sorbents permanently bound to construction materials (fixed sorbent materials-FSMs) or mixed with construction materials (sorbent polymer composites-SPCs). The approach is unique in the world literature as well as the development of three stands and procedures enabling the testing of FSMs or SPC materials based on Tarflen as a construction material. In order to further tests of FSMs and SPCs, the system for laboratory tests and two systems for industrial tests are developed. These stands and procedures enable determination of the influence of: FSM or SPC module shapes, flue gas properties (e.g., composition, temperature, flow rate), and mercury concentration on the effectiveness of mercury removal by SPCs and FSMs. In this paper, the influence of module shapes, gas velocity, and temperature is particularly considered. In the final industrial tests, the FSM removes 99.5% Hg after 42 days and the SPC removes from 99.5% to 82.3% after 34 days.Web of Science1523art. no. 889

Návrh úprav roštového kotle ČKD Dukla R16 pro optimalizaci provozu se zřetelem na zvýšení účinnosti kotle a minimalizaci tvorby škodlivin

Import 20/04/2006Prezenční výpůjčkaVŠB - Technická univerzita, Fakulta strojní, Katedra energetik

Tvorba N2O ze spalovacích procesů

Import 20/04/2006Prezenční výpůjčkaVŠB - Technická univerzita Ostrava. Fakulta strojn

Experimental Modelling of Autoignition Temperature for Alkyl/Alkenyl Products from Fischer-Tropsch Synthesis

Interest in Fischer-Tropsch technology is increasing rapidly. Alkyl/alkenyl products from Fischer-Tropsch synthesis are alternative, renewable, environmentally and economically attractive fuels and there are considered one of the most favorable fuels for conventional fossil-based fuels. The chemistry of this gas-to-liquid industry converts synthesis gas containing carbon monoxide and hydrogen to oxygenated hydrocarbons such as alcohols. The fire hazards associated with the use of these liquid hydrocarbons mixtures are obvious. This article aims to explore the fundamental fire and explosion characteristics for main products composition from Fischer-Tropsch synthesis

Experimental Modelling of Autoignition Temperature for Alkyl/Alkenyl Products from Fischer-Tropsch Synthesis

Interest in Fischer-Tropsch technology is increasing rapidly. Alkyl/alkenyl products from Fischer-Tropsch synthesis are alternative, renewable, environmentally and economically attractive fuels and there are considered one of the most favorable fuels for conventional fossil-based fuels. The chemistry of this gas-to-liquid industry converts synthesis gas containing carbon monoxide and hydrogen to oxygenated hydrocarbons such as alcohols. The fire hazards associated with the use of these liquid hydrocarbons mixtures are obvious. This article aims to explore the fundamental fire and explosion characteristics for main products composition from Fischer-Tropsch synthesis