A comparison of PAH emission sampling methods (cyclone, impactor) in particulate and gaseous phase

Four different domestic heating boilers and four types of fuel (lignite, wet wood, wood pellets and mixed fuel) were tested, and the emissions of the particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) were correlated. Dekati low-pressure impactor (DLPI, Dekati) sorting of the PM fractions into PM0.1, PM1, PM2.5 and PM10 was used to determine the emission factors of the PAHs in a dilution tunnel via isokinetic sampling and was compared with a cyclone (Tecora). The 4 PAHs were mostly detected on the fine particles of PM1 in the DLPI and on the fine particles of PM2.5 in the cyclone, and in some cases, they were mainly detected in polyurethane foam (PUF) used for the collection of the gas phase placed behind the DLPI and cyclone. The effectiveness of DLPI sampling was generally comparable or lower than the cyclone sampling of the range 0.01-1.33 mg kg(-1).Web of Science18485584

Rozšíření měřicího rozsahu pádové trubky na výzkumném energetickém centru

Better understanding of combustion process in large scale pulverized coal boilers can help with increasing of coal combustion efficiency and decreasing of pollutant emissions, such as nitrogen oxides and arguable carbon dioxide. This improvement cannot be performed without testing in labor-atory conditions. For this purpose, a new testing facility called the drop tube has been built in the Energy Research Center (ERC) of VSB-Technical University of Ostrava. This paper describes the methodology of pulverized coal thermo-kinetic properties determination with the use of the Drop Tube Test Facility and the first steps in improvement of this methodology. There is a new design of the sampling probe, an improved one, gas-tight double-wall design, implemented into the methodolo-gy lately. The intermediate space is vacuumed for the purpose of better isolating properties of the probe. Further, the probe is newly supplemented with a cryogenic control valve for smooth regulation of small flow rates of cooling media - liquid nitrogen. These innovations bring cooling media sav-ings, especially thanks to increased efficiency of this media’s cooling potential. Furthermore, smoother regulation allows a sample cooling in an accurately defined point.Lepší pochopení spalovacího procesu ve velkých práškových uhelných kotlích může pomoci se zvyšováním efektivity spalování uhlí a snížením emisí znečišťujících látek jako jsou oxidy dusíku a diskutabilní oxid uhličitý. Tato zlepšení není možné provést bez laboratorního zkoušení. Pro tento účel bylo na Výzkumném energetickém centru VŠB-Technické univerzity Ostrava postaveno nové testovací zařízení nazvané pádová trubka. Tento článek popisuje metodiku stanovení termo-kinetických vlastností uhelného prášku s použitím pilotního testovacího zařízení pádové trubky a popisuje první kroky ke zlepšení této metodiky. Do metodiky je nově začleněna druhá vylepšená verze odběrové chladící sondy, která je vyhotovena v plynotěsném dvouplášťovém provedení. Mezi-prostor je pro zlepšení izolačních vlastností sondy evakuován. Dále je sonda nově doplněna kryogenním regulačním ventilem pro jemně nastavitelné dávkování chladícího média – tekutého dusíku. Tyto inovace přináší úspory ve spotřebě chladícího media zejména díky zvýšení účinnosti chladícího potenciálu tohoto media. Dále plynulejší regulace umožňuje zchlazení vzorku v přesně definovaném místě

Effects of the type of biomass and ashing temperature on the properties of solid fuel ashes

Ashes were prepared by annealing selected types of solid fuels (biomass: corn cobs, sunflower husks, olive pomace, hay pellets and rice husks; coal: lignite and bituminous; and alternative fuel: paper sludge) at different temperatures (550 degrees C, 815 degrees C and 975 degrees C). Based on X-ray fluorescence spectra, the slagging/fouling indexes were used to study the effects of the type of ash and the ashing temperature on the ash fouling and slagging properties. Slagging indexes were compared with the ash fusion temperatures. Ash fusion temperatures were measured by a LECO AF-700. The lowest deformation temperature (below 1000 degrees C) was seen for the ashes prepared from hay pellets and corn cobs. On the other hand, the deformation temperature exceeded 1500 degrees C for ashes prepared from paper sludge, sunflower husks and rice husks. By calculating the different slagging/fouling indexes, all the ashes exhibited slagging/fouling problems of varying degrees.Web of Science212514

Influence of fuel mixture and catalyst on the ethanol burner flue gas composition

The aim of this study is to determine the influences of chosen primary (mixing of standard recommended fuel with additives) and secondary (oxidation catalyst) measures on the composition of flue gas, produced by combustion of liquid fuels in a standard ethanol burner. The total amount of emitted NO x was decreased by 63%, after replacing the fuel by pure methanol, while the total amount of emitted CO was the lowest during pure ethanol usage. The implementation of chosen catalyst significantly affected the total amount of emitted CO with high conversion rates (82%-90%). The amount of emitted water vapour was increased by 0%-25% (per 1 kWh of released energy) when additives were used. Overall, applying the mentioned measures together proved to be very beneficial from the total amount of emitted CO and NOx point of view.Web of Science887987

Heat energy accumulation construction for bioethanol burner

Commonly sold bioethanol fireplaces can represent significant heat source, however due to their intermittent operation the heat energy output is strongly uneven. The aim of this study was to determine the possibilities of heat energy accumulation by individually built ethanol fireplace intended for commonly sold ethanol burner installation. For the measurements of heat energy output, long term tests of the individually built ethanol fireplace with 1, 2 and 3 consecutive combustion periods in a unique calorific room were performed. Accumulation ethanol fireplace has proven high ratio between accumulated heat energy after the ethanol burner last burn-out reaching from 21.4 to 48.4% according to the number of consecutive fuel doses. By usage of the described ethanol fireplace the time of heat energy releasing was increased from approximately 1.15, 2.35 and 3.55 h in case of ethanol burner usage in a non-accumulation fireplace for 1, 2 and 3 fuel doses to 6.5, 11 and 15 h in case of accumulation ethanol fireplace usage. This was also strongly connected with average heat output ranging between 2.54 to 2.47 kW in the case of ethanol burner usage in a non-accumulation ethanol fireplace and 0.38 to 0.59 kW in the case of accumulation ethanol fireplace usage.Web of Science911410

Coagulation contributing to electrostatic precipitation of ultrafine fly ash from small-scale biomass combustions

An electrostatic precipitator (ESP) is an efficient device for removing fly ash from small-scale solid-fuel com-bustion. Under corona discharge, a gaseous medium becomes ionised, and particles become charged by colliding with ions. An electric field forces the movement of charged particles to remove gases and induces the movement of generated ions, causing secondary electrohydrodynamic flow. Thus, particle charge, the presence of neigh-bouring particles, an ESP electric field, and gas flow turbulence can enhance particle coagulation. Therefore, the ultrafine particle concentration in an ESP is expected to evolve under electrostatic removal and enhanced coagulation. In the present study, the contribution of coagulation is explored and confirmed using experimental measurements performed on an ESP used to control emissions from a 160-kW boiler with biomass combustion. The ESP was operated under several modes to obtain different coagulation conditions. Changes in particle concentrations were measured simultaneously using two techniques. It was found that coagulation could be responsible for up to 5% of the total removal efficiency, depending on the ESP operation parameters. The present study can promote a deeper understanding of the processes involved in electrostatic precipitation, and the ob-tained results can be useful for practical ESP engineering.Web of Science16art. no. 10066

Specifics of electrostatic precipitation of fly ash from small-scale fossil fuel combustion

This paper investigates the removal efficiency of a honeycomb electrostatic precipitator (ESP) applied to control particulate matter (PM) emissions from a small-scale boiler with combustion lignite and hard coal. The specifics of the precipitation of emissions from small-scale boilers are discussed, and the design principles for relevant ESPs are presented and used. The ion-induced nucleation of sulfuric acid occurred, causing the drastic penetration of 19 nm particles through the ESP. Despite this, the overall collection efficiency was sufficient to meet the EU’s Ecodesign Directive requirements. Back corona was not detected. The optimal ESP performance is defined with further parameters: a current density of 0.5 mA/m2 at an electric field strength of about 2.7 × 105 V/m; a minimal specific collecting area of ESP (SCA) of 60 m2/(m3/s); and Nt-product of 4.5 × 1014 s/m3 . Such parameters of ESPs should ensure adequate PM emissions control for any type of boiler with similar emissions characteristics. The composition of collected fly ash particles was analysed, and a method for fly ash utilisation was proposed. This research may be helpful for designing ESPs to control PM emissions for small-scale units with fossil fuel combustion.Web of Science113art. no. 80

Long-term neutralization of acidic condensate from gas condensing boilers

The pH of wastewater needs to remain between 6 and 9 to protect water organisms. Condensates from a gas condensing boiler have a pH value of about 3. An optimal way to neutralize the acid condensate is to use cheap material such as dolomite. An old-style neutralization box (NB) was tested with a standard faction of dolomite. However, it did not sufficiently neutralize the condensate. Therefore, several tests were performed involving changes to the construction of the neutralization box, a finer fraction of dolomite and aerating the condensate in the neutralization box. In summary, a new NB technology with partitions, a finer fraction of dolomite and condensate aeration proved sufficient in the neutralization of the pH of the condensate in the short and long terms. It depends on what material the heat exchanger is made of in the condensing boiler. The aluminum content reduces the effectiveness of dolomite in the long run, so aerating the condensate in the NB is recommended, which leads to its more effective neutralization.Web of Science1422art. no. 1501

Emission Factors from the Combustion of Solid Fuels in Domestic Appliances.

Import 11/04/2012Disertační práce se zabývá stanovením emisních faktorů vybraných znečišťujících látek pro spalovací zdroje malých výkonů. Experimentálně stanovené emisní faktory jsou srovnávány s emisními faktory používanými pro národní inventury emisí ČR. Práce je rozdělena do šesti hlavních částí: První kapitola „Úvod“ v němž jsou stanoveny cíle disertační práce. Druhá kapitola „Teoretická část“ stručně uvádí čtenáře do problematiky bilancování emisí, seznamuje se současnými emisními faktory a nastiňuje problematiku jejich stanovování. Třetí kapitola „Metodika experimentů“ předkládá konkrétní konstrukce spalovacích zařízení, parametry paliv, speciální trať pro odvod spalin a metody vzorkování škodlivin a sledování tepelně technických parametrů provozu spalovacích zařízení. Čtvrtá kapitola nazvaná „Experimenty“ popisuje průběh provedených experimentů. Tyto informace jsou nezbytné pro pochopení a správnou interpretaci výsledků. Pátá kapitola „Výsledky„ je rozdělena do několika podkapitol. Každá podkapitola je věnována konkrétní znečišťující látce nebo skupině látek. Jednotlivé podkapitoly se věnují: oxidu uhelnatému, oxidům dusíku, oxidu siřičitému, nemetanovým těkavým organickým látkám, tuhým znečišťujícím látkám, dioxinům a furanům, polychlorovaným bifenylům, hexachlorbenzenu a polyaromatickým uhlovodíkům. Každá látka nebo skupina látek je stručně představena, jsou nastíněny rizika s jejím výskytem v ovzduší a mechanismus vzniku. Jsou představeny naměřené experimentální výsledky uspořádané podle druhu spalovaného paliva, použité konstrukce spalovacího zařízení a způsobu provozu zařízení. Výsledky jsou diskutovány a je provedeno jejich zobecnění pro využití v ČR. Zobecněné experimentálně stanovené emisní faktory jsou porovnány s emisními faktory používanými v ČR a s emisními faktory doporučovanými pro státy EU v dokumentu EMEP/EEA emission inventory guidebook 2009 - Part B - 1. A.4. small combustion. Tyto tři sady emisních faktorů jsou aplikovány na modelovou spotřebu tuhých paliv a zemního plynu v domácnostech v ČR v roce 2006 a jsou tak demonstrovány dopady užití různých emisních faktorů na odhad množství emisí ze sektoru vytápění domácností. Šestá kapitola „Závěr“ shrnuje nejdůležitější poznatky disertační práce. Rozděluje znečišťující látky na dvě kategorie. Jednou kategorií jsou znečišťující látky jejichž vznik je prioritně spjat s vlastnostmi spalovaného paliva a druhou skupinou jsou znečišťující látky jejichž vznik je prioritně spjat s kvalitou spalovacího procesu, tedy s konstrukcí spalovacího zařízení. A dále se kapitola zamýšlí nad možnostmi snižování emisí z malých zdrojů.The dissertation thesis deals with determination of emission factors of selected pollutants in households. Experimentally determined emission factors are compared with the emission factors used for national emission inventories in the Czech Republic. The thesis is divided into six main sections: The "Introduction" part, which specifies the objectives of the dissertation thesis. The “Theoretical part” is briefly introducing readers to the problems of balancing emissions, acquaints with the current emission factors and outlines the problems with their determination. The third section "Methodology of experiments" presents particular design of combustion equipment, fuel parameters, a special track for flue gas exhaust and methodology of sampling of pollutants and monitoring of thermal parameters of combustion plants. The fourth chapter, entitled "Experiments", describes the course of experiments carried out. This information is necessary for proper understanding and interpretation of results. The fifth chapter "results" is divided into several sections. Each subsection is devoted to a particular pollutant or group of substances. Individual subsections are dedicated to: carbon monoxide, nitrous oxide, sulfur dioxide, non-methane volatile organic compounds, solid pollutants, dioxins and furans, polychlorinated biphenyl, hexachlorobenzene and polyaromatic hydrocarbons. Every substance or group of substances is briefly introduced, the mechanism of their formation and the risks of their occurrence in the atmosphere are outlined. The chapter also presents experimental results obtained, which are organized by the type of fuel burned, the construction of incinerator and method of operation used. The results are discussed and generalized for the use in the country. The generalized experimentally determined emission factors are compared with the emission factors used in the Czech Republic and the emission factors recommended for the EU in the document EMEP / EEA Emission Inventory Guidebook 2009 - Part B - 1 A.4. small combustion. These three sets of emission factors are applied to model consumption of fossil fuels and natural gas in households in the Czech Republic in 2006 and thus the effects of using different emission factors to estimate emissions from domestic heating sector are demonstrated. The sixth chapter 'Conclusion' summarizes the main findings of the dissertation. It divides pollutants into two categories. First category contains pollutants whose formation is mainly related to the characteristics of burned fuel and the other category contains pollutants whose formation is mainly related to the quality of the combustion process, and thus to the construction of the incinerator. The chapter further examines the options for reducing emissions from small sources.Prezenční546 - Institut environmentálního inženýrstvívyhově