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

CFD model of SNCR with shifting effect of CO

The paper deals with CFD simulation of SNCR technology with implemented CO temperature shift. The influence of CO on the SNCR process is described by empirical adjustment of kinetics parameters of chemical reactions. Results of CFD simulation were compared with results of experimental measurements. Although the proposed kinetics model of SNCR technology is simplified, it is able to describe reduction of NOx and other phenomena of SNCR with good precision. The model can be used to verify of injection levels and injection lances arrangement at design phase.Web of Science2012210

Studie úprav fluidního kotle K11 N v a.s. Energetika Třinec pro spalování hnědého uhlí

Import 20/04/2006Prezenční výpůjčkaVŠB - Technická univerzita Ostrava. Fakulta strojní. Katedra (361) energetik

Využití alternativních sorbentů při odsířování ve fluidních ohništích s cirkulující fluidní vrstvou

Import 20/04/2006Prezenční výpůjčka341 - Katedra energetik

Wastewater management in a closed cooling system of professional power plant

The paper presents a mathematical model describing the changes in SO42- concentration in a closed system of cooling water in a professional power plant. The analyzed installation consists of condensers and cooling towers connected by a system of channels. The main mechanism of heat transfer in the cooling tower bases on partial evaporation of water, resulting in the increase of concentration of SO42- ions in the circulating liquid. The only mechanism to decrease concentration of undesirable chemicals in the circulating water is its periodic discharge to a wastewater treatment. According to the latest Polish Government Regulations (Regulation of the Ministry of Environment dated 18 November 2014) and the Directive of the European Parliament and of the Council (2010/75/EU of 24 November 2010 on industrial emissions) from the beginning of 2016 the new limits on the chemical components of a wastewater led to the natural tanks has been accepted, what forced planned and cost-effective wastewater treatment in a professional power plants. Presented mathematical model has an analytical solution which allows not only to predict daily changes of SO42- concentration in circulating water but also to indicate asymptotic concentration of sulphate ions under given working parameters of the system and to calculate minimal volumetric flow rate of wastewater required to keep the SO42- concentration below legal value.W pracy przedstawiono model matematyczny opisujący zmianę stężenia jonów siarczanowych SO42- w zamkniętym obiegu wody chłodzącej bloku energetycznego. Analizowana instalacja obejmuje: skraplacze bloków energetycznych oraz chłodnie kominowe połączone systemem kanałów ssących i kolektorów tłocznych. Głównym mechanizmem wymiany ciepła w chłodni jest częściowe odparowanie przepływającej przez nią wody, co powoduje jednak wzrost stężeń związków chemicznych w cyrkulującej cieczy i wymusza okresowy zrzut części wody do przyzakładowej oczyszczalni ścieków. Zgodnie z najnowszymi rozporządzeniami prawnymi: Rozporządzeniem Ministra Środowiska z dnia 18 listopada 2014 roku oraz dyrektywą Parlamentu Europejskiego i Rady 2010/75/UE z dnia 24 listopada 2010 r. w sprawie emisji przemysłowych, od początku roku 2016 obowiązują nowe limity dotyczące składu chemicznego ścieków technologicznych kierowanych do zbiorników naturalnych, które wymuszają planową i oszczędną gospodarkę wodnościekową elektrowni. Prezentowany model matematyczny posiada analityczne rozwiązanie pozwalające nie tylko przewidzieć dobowe zmiany stężeń siarczanów w cyrkulującej wodzie, ale również określić graniczne stężenie jonów siarczanowych dla bieżących parametrów pracy układu oraz wyznaczyć minimalny strumień odprowadzanych ścieków zapewniający spełnienie norm emisji ścieków przemysłowych.Web of Science19645

Sestavení materálové bilance mlýnského okruhu s ventilátorovým mlýnem

Článek popisuje sestavení materiálové bilance mlýnského okruhu s ventilátorovým mlýnem a dále se zaměřuje na problémy spojené s měřením nebo stanovením některých veličin.This paper deals with assembling the mass balance of pulverizing circuit with fan mill and is focused on issues in measurement and assessment of some quantities

Mercury emission from three lignite-fired power plants in the Czech Republic

The main aim of the research was to estimate mercury emissions from three selected power plants in the Czech Republic, where lignite is burnt, as well as to conduct a comprehensive measurement of Hg in fuels, fly ash and desulfurization products. The average concentrations of the mercury in fuel were as follows: for Power Plant 1 it was 0.19 +/- 0.01 mg/kg, in the case of power plants 2 and 3 it was 0.24 +/- 0.03 mg/kg and 0.23 +/- 0.02 mg/ kg, respectively. The average concentrations of mercury in the flue gas, at the stack, were the following: for Power Plant 1-19.5 +/- 2.9 mu g/m(N)(3), for Power Plant 1-19.9 +/- 3.0 mu g/m(N)(3) and for power plant 3-23.5 +/- 3.5 mu g/ m3N. In all three cases, the mercury emission level exceeds the planned permissible emission level, 7 mu g/m(N)(3). The percentage of the mercury removed by means of the flue gas purification systems installed in the power plants varied from approximately 30 to 53%. The efficiency of mercury removal with the fly ash in the electrostatic precipitators ranged from 2 to 52%. The efficiency of mercury removal in the SO2 removal systems ranged from about 1 to 30%.Web of Science212art. no. 10662

Mercury removal and its fate in oxidant enhanced wet flue gas desulphurization slurry

Mercury is a toxic heavy metal that, once emitted or released, persists in the environment and circulates between air, water, sediments, soil and living creatures. Therefore, international governments and other authorities are taking measures to control mercury emissions from various sources. Despite many efforts, mercury remains a problematic pollutant in coal-fired installations in regards to differentiation of existing forms and their behavior in flue gas stream and purification units. Scientists try to understand its behavior in the flue gas and to capture it in one place, employing processes of adsorption, absorption, membranes or different catalysis. At the same time, researchers are also developing efficient and economically feasible technologies for mercury control. One such technology involves the capture of mercury in flue gases via gas-cleaning units through co-benefit application. Examples include, for instance, carbon injection in ESP, catalytic conversion in SCR unit, and absorption in a wet desulfurization scrubber. This paper outlines a mercury capture method developed in American and Polish laboratories and will present the pilot-scale research with emphasize on the mercury behavior in the slurry with and without any added reagents.Web of Science21188287

Characteristic of mercury on the surface of ash originating from electrostatic precipitators of lignite and bituminous coal-fired power plants

Mercury concentrations in ash taken from electrostatic precipitations (ESPs) installed in bituminous coal and lignite power plants have been analyzed by the X-ray fluorescence (XRF) method and leaching test supported by detailed coal and ash compositions' analyses, surface scans and particles size distribution studies. The results showed that mercury was present on the surface of ash particles. Its concentration decreased upon increasing size of ash particles. Leaching tests showed that only small part of mercury was removed with water which suggests the fact that it occurred mostly in the form of insoluble compounds such as Hg, HgO, HgS and Hg2Cl2. There existed ash particles of the diameters from 50 to 60 gm, characterizing by the maximum capability to adsorb mercury and its compounds. The authors suggest that metals like copper and lead formed ash active centers that were preferably occupied by molecules containing atoms of mercury. It was highly possible to expect that content of these elements in ash would have a significant effect on sorption of mercury from combustion gases.Web of Science454594