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

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

N2O emissions from production of HNO3

Nitrous oxide (N2O) belongs to greenhouse gases and damages the stratospheric ozone. Production of HNO3 is the main industry source of N2O emissions. Mechanism of formation of N2O have been described and the results of measurements of N2O emission have been presented from several HNO3 plants differing by the pressure of the ammonia combustion and NOx abatement technologies.Podtlenek azotu (N2O) jest zaliczany do grupy gazów cieplarnianych, który uszkadza warstwę ozonową. Największym przemysłowym źródłem emisji N2O jest produkcja kwasu azotowego. Opisano mechanizm powstawania N2O i wyniki pomiarów jego emisji N2O z wybranych technologii produkcji HNO3, które różnią się ciśnieniem w procesie spalania amoniaku i technologią denitryfikacji

Emisní faktory vybraných organických sloučenin ze spalování tvrdého dřeva v malých spalovacích zařízeních

Emission factors were determined during beech logs combustion in four domestic facilities typical for Central European region households. In flue gases there were determined except basic pollutants (NOx, CO, PM and OC as TOC ) also selected organic pollutants as PCBz, PCPh, PAH, PCB, and PCDD/F. Generally, obtained EF values of selected pollutants were lower for modern combustion facilities than for older ones. However, some differences were found between modern facilities in dependence on their type as well. For better understanding results were also subjected to principal component analysis.Emisní faktory (EF) byly stanoveny při spalování bukového dřeva ve čtyřech typech malých spalovacích zařízeních typických pro domácnosti středoevropského regionu. Ve spalinách byly sledovány základní znečišťující látky (NOx, CO, PM a VOC jako TOC) a také vybrané organické znečišťující látky PCBz, PCPh, PAU, PCB a PCDD/F. Obecně lze konstatovat, že naměřené EF vybraných znečišťujících látek byly nižší při použití moderních typů spalovacích zařízení než na zařízeních starších konstrukcí. Nicméně, jsou také pozorovány rozdíly mezi jednotlivými moderními zařízeními v závislosti na jejich typu. Pro lepší pochopení výsledků byla naměřená data rovněž zpracovaná komponentní analýzou

Composition of ashes from the combustion of solid fuels and municipal waste in households

In this study, 73 ash samples (comprising 49 ash samples from combustion tests performed in 2017, and 24 ash samples from combustion tests performed during 2014-2016 at the Energy Research Center, Ostrava, Czech Republic) were analysed. Ash samples were obtained via the combustion of various solid fuels, their mixtures with municipal waste (floor coverings, paper, polyethylene terephthalate (PET) briquettes, plastics, and textiles), and municipal wood waste (furniture chipboard, window frames) in household combustion units, such as an overfire boiler, boiler with downdraft combustion, gasification boiler, automatic boiler, and stove. The aim of this study was to determine the composition of representative ash samples from solid fuels and municipal waste and to determine which parameters (metals and halides) were present in the ash analysis after waste incineration. Statistical evaluation of box plots with the determination of the boundaries for outliers and extreme values was performed. Finally, six metals (Sb, Cu, Pb, Sn, Ti, and Zn), together with chlorides, were taken as the indicators of municipal waste incineration in households. The highest value of Sb was 344 mg/kg in plastics + dry beech; the highest value of Cu was 30,500 mg/kg in textiles + black coal (B1); the highest concentration of Pb was 1,360 mg/kg in floor coverings + dry beech; the highest value of Sn was 108 mg/kg in textiles + dry beech; the highest concentration of Ti was 38,200 mg/kg in window frames; the highest value of Zn was 215,000 mg/kg in window frames; and the highest concentration of chlorides was 191,000 mg/kg in floor coverings + dry beech.Web of Science248art. no. UNSP 10926

The impact of co-combustion of polyethylene plastics and wood in a small residential boiler on emissions of gaseous pollutants, particulate matter, PAHs and 1,3,5-triphenylbenzene

The aim of this study was to simulate a banned but widely spread practice of co-combustion of plastic with wood in a small residential boiler and to quantify its impact on emissions of gaseous pollutants, particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and 1,3,5-triphenylbenzene (135TPB), a new tracer of polyethylene plastic combustion. Supermarket polyethylene shopping bags (PE) and polyethylene terephthalate bottles (PET) were burnt as supplementary fuels with beech logs (BL) in an old-type 20 kW over-fire boiler both at a nominal and reduced heat output. An impact of co-combustion was more pronounced at the nominal heat output: an increase in emissions of PM, total organic carbon (TOC), toxic equivalent (TEQ) of 7 carcinogenic PAHs (c-PAHs) and a higher ratio of c-PAHs TEQ in particulate phase was observed during co-combustion of both plastics. 135TPB was found in emissions from both plastics both at a nominal and reduced output. In contrast to findings reported in the literature, 135TPB was a dominant compound detected by mass spectrometry on m/z 306 exclusively in emissions from co-combustion of PE. Surprisingly, six other even more abundant compounds of unknown identity were found on this m/z in emissions from co-combustion of PET. One of these unknown compounds was identified as p-quaterphenyl (pQ). Principal component analysis revealed strong correlation among 135TPB, pQ and five unknown compounds. pQ seems to be suitable tracers of polyethylene terephthalate plastic co-combustion, while 135TPB proved its suitability to be an all-purpose tracer of polyethylene plastics combustion.Web of Science196241

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°C, 815°C and 975°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°C) was seen for the ashes prepared from hay pellets and corn cobs. On the other hand, the deformation temperature exceeded 1500°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

Evaluation of waste blends with sewage sludge as a potential material input for pyrolysis

In line with the requirements of the circular economy, the European Union's waste management legislative changes also concern the treatment of sewage sludge. Although sewage sludge production cannot be prevented, its quantities may be reduced by the synergetic effect of energy recovery via choosing a proper technology. Sewage sludge is difficult to apply as fuel alone, because of its high moisture and ash content. However, its energy use will be increased by adding suitable waste materials (different types of plastics, waste tires and paper rejects). Most recently, the thermal utilization of sewage sludge via incineration or pyrolysis has grown in importance. This article describes the fuel parameters of particular waste materials and of their blends with sewage sludge in connection with laboratory-scale thermal decomposition in an inert atmosphere, for their potential use in a semi-pilot plant pyrolysis unit. For pyrolytic application, the results of thermogravimetric analysis are needed in order to know the maximal temperature of thermal decomposition in an inert atmosphere, maximal mass losses, and weight loss rates. The samples of different thermoplastics mixed with sewage sludge, and low-density polyethylene blends with sewage sludge, had the lowest residual masses (70-74%) and the highest weight loss rates (11-19%/min). On the other hand, the blend of polyester rejects from tire processing, paper rejects and sewage sludge had the second highest residual mass (60%) and the lowest weight loss rate (3%/min).Web of Science114art. no. 161