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Number of results: 41
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Abstract

The use of biomass in the energy industry is the consequence of ongoing efforts to replace Energy from fossil fuels with energy from renewable sources. However, due to the diversity of the biomass, its use as a solid fuel generates waste with diverse and unstable chemical composition. Waste from biomass combustion is a raw material with a very diverse composition, even in the case of using only one type of biomass. The content of individual elements in fly ash from the combustion of biomass ranges from zero to tens of percent. This makes it difficult to determine the optimal recovery methods. The ashes from the combustion of biomass are most commonly used in the production of building materials and agriculture. This article presents the elemental composition of the most commonly used biomass fuels. The results of the analysis of elemental composition of fly ashes from the combustion of forest and agricultural biomass in fluidized bed boilers used in the commercial power industry were presented. These ashes are characterized by a high content of calcium (12.3–19.4%), silicon (1.2–8.3%), potassium (0.05–1.46%), chlorine (1.1–6.1%), and iron (0.8–6.5%). The discussed ashes contained no sodium. Aluminum was found only in one of the five ashes. Manganese, chromium, copper, nickel, lead, zinc, sulfur, bismuth, titanium and zirconium were found in all of the examined ashes. The analysis of elemental composition may allow for a preliminary assessment of the recovery potential of a given ash.
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Abstract

Petrographic and physico-chemical analyses of ashes are carried out on a large scale and presented in numerous scientific papers. The mentioned ashes are obtained from filters and electrostatic precipitators mounted in large industrial installations. The large-scale analysis of the ashes obtained directly from grate furnaces or blast furnaces mounted in low-power boilers started with combating smog and low-stack emissions. The collection of ash samples from household furnaces usually involves the analysis of the combustion of waste in low-power boilers. This is justified in the case of old type boilers, which were designed to use virtually any fuel. Currently, new types of boilers, designed to burn dedicated fuels, are offered on the market. The aim is to use only renewable fuels (biomass) or fossil fuels with high quality parameters, which are more environment-friendly, e.g. eco-pea coal, lignite briquettes, or peat briquettes. The authors of the study focused on examining the ash obtained from boilers for burning wood pellets by performing microscopic analysis of residues after biomass combustion. The above mentioned analysis provides a comprehensive information on the efficiency of the combustion process, the content of contaminants remaining in the ash, and the suitability of ash for other applications. The entire process, from the moment of collecting the samples to the execution of the analysis takes up to 12 hours, which ensures a quick decision on furnace adjustment or fuel change. The ash components were determined based on the results obtained by the Fly-Ash Working Group of the International Committee for Coal and Organic Petrology (ICCP). The mentioned classification has been supplemented with new key elements occurring in ashes resulting from the combustion of wood pellets in household boilers. This allowed determining the percentage content of characteristic components in the tested material, which can be used as a specific benchmark when issuing opinions on the quality and efficiency of the boiler and the combusted pellets.
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Abstract

The problem of of the use of fly ash still constitutes a research and exploration area for scientists. This is due to the fact that, 6,000,000 Mg of coal combustion by-products (CCB) are storage on landfills yearly in Poland alone. One of the potential directions of using fly ash is to use it as a substrate in hydrothermal syntheses of mesoporous materials (synthetic zeolites). Zeolites are aluminosilicates with a spatial structure. Due to their specific structure they are characterized by a number of specific properties among others molecular-sieve, ion-exchange and catalytic that can be used in engineering and environmental protection. So far, the synthesis has been carried out using coal combustion by-products such as fly ash or microsphere. The article analyzes whether separation from the fly ash of the appropriate fraction (below 63 μm) will affect the formation of zeolite grains. The syntheses were carried out using class F fly ash and the fraction separated from it, which was obtained by sieving the ash through a 63 μm sieve. Chemical (XRF) and mineralogical (XRD, SEM-EDS) analyzes were carried out for substrates as well as the obtained reaction products. In the case of substrates, the analysis did not show any significant differences between the ash and the separated fraction. However, in products after synthesis (Na-X zeolite with a small amount of Na-P1 zeolite, and small amounts of quartz and unreacted aluminosilicate glass - mullite) higher aluminum and sodium contents were observed from the separated fraction, with a lower calcium and potassium content. A small proportion of illite was observed on the diffraction curve of the zeolite from the fraction. Observations of grain morphology showed no differences in formation. Based on the conducted analyzes, it can be stated that, considering the economics of the synthesis process, the separation of fine fractions from the fly ash does not affect the quality of the synthesis process.
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Abstract

In the process of determining the content of impurities, including fossil fuels, crude oil, coke, pitch, plastics, glass, slag, rust, metals, and rock dust, in charcoal and wood briquettes via microscopic examination, the question of the use of ashes from the combustion of grill fuels (taking the scale of the new national sport into account, commonly referred to as „weekend grilling”) was raised. Another reason for addressing this issue was the question regarding the use of organic additives to acidified soil (mineral) fertilizers submitted by one of the clients of the bituminous coal and reservoir rocks analysis laboratory. In addition, the manufacturer of gardening soil has also expressed an interest in an unconventional deacidifying agent; the introduction of a new product with a unique ingredient is considered as a chance to stand out from the competition. A review of the literature shows that attempts to use ashes obtained from the biomass combustion in power boilers have been made. However, due to the biomass composition and additives and pollutants used in biomass for energy purposes, the production of such mixtures has been dropped. Based on the data from numerous samples of grill fuel, which meet the requirements regarding the content of impurities set out in the PN-EN 1860-2 standard, the question of the possible use of ash obtained from charcoal and wood briquette grilling as a component for use in the production of acidified soil (mineral) fertilizers was discussed. The article will present the amount of material obtained based on the statistical sales of barbecue fuels based on the experimentally calculated ash mass resulting from the combustion of 1 kg of starting material. In addition, a logistic proposal for obtaining ash from individual grill users will be developed. On the day of the submission of the present work, the results of the chemical analysis of charcoal and wood briquettes subjected to the gasification process have not yet been obtained. However, based on the microscopic analysis, it can be concluded that the content of impurities in the examined samples is highly unlikely to prevent the use of the mentioned ashes in agriculture.
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Abstract

Based on laboratory tests of selected properties of secondary waste (ashes and dusts) from municipal waste incineration plants, the possibility of recovering some properties of waste in the process of filling the post-mining voids in the salt mine was assessed. The furnace bottom ash and the waste from the flue gas treatment from one of the national incineration plants were examined. The grain curves of dry waste and the density of the prepared mixtures were characterized. Twelve variants of the compositions of ash-based mixtures with varying proportions of the individual components were considered, taking into account both fresh water and brine. For each variant of the composition, the amount of redundant liquid appeared as well as the time of solidifying of the mixture to a certain strength and the compressibility values obtained. Considering the possibility of transporting mixtures in mines by means of pipelines at relatively long distances, and allowing the filling of large salt chambers to be filled and evenly filled, flow parameters were determined. In addition, the permeability of solidified waste samples was investigated, showing the potential for reducing the strength of the waste mass due to the action of water or brine. The technical feasibility of eliminating redundant liquid in the binding process has been confirmed, which is particularly important in salt mines. Preliminary values for the amount of binder (5%÷10%) to be added to the mixtures to obtain the specified strength properties of the artificially formed mass at Rc = 0.5 MPa. Attention was paid to the important practical aspect resulting from the rapid increase of this type of waste in the comming years in Poland and at the same time vast potential for their use in salt mining, where we have a huge capacity of salt chambers available.
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Abstract

The issue of mercury emission and the need to take action in this direction was noticed in 2013 via the Minamata Convention. Therefore, more and more often, work and new law regulations are commencing to reduce this chemical compound from the environment. The paper presents the problem of removing mercury from waste gases due to new BREF/BAT restrictions, in which the problem of the need to look for new, more efficient solutions to remove this pollution was also indicated. Attention is paid to the problem of the occurrence of mercury in the exhaust gases in the elemental form and the need to carry out laboratory tests. A prototype installation for the sorption of elemental mercury in a pure gas stream on solid sorbents is presented. The installation was built as part of the LIDER project, financed by the National Center for Research and Development in a project entitled: “The Application of Waste Materials From the Energy Sector to Capture Mercury Gaseous Forms from Flue Gas”. The installation is used for tests in laboratory conditions in which the carrier gas of elemental mercury is argon. The first tests on the zeolite sorbent were made on the described apparatus. The tested material was synthetic zeolite X obtained as a result of a two-stage reaction of synthesis of fly ash type C with sodium hydroxide. Due to an increase, the chemical affinity of the tested material in relation to mercury, the obtained zeolite material was activated with silver ions (Ag+) by an ion exchange using silver nitrate (AgNO3). The first test was specified for a period of time of about 240 minutes. During this time, the breakthrough of the tested zeolite material was not recorded, and therefore it can be concluded that the tested material may be promising in the development of new solutions for capturing mercury in the energy sector. The results presented in this paper may be of interest to the energy sector due to the solution of several environmental aspects. The first of them is mercury sorption tests for the development of new exhaust gases treatment technologies. On the other hand, the second aspect raises the possibility of presenting a new direction for the management and utilization of combustion by-products such as fly ash.
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Abstract

The exploitation and processing of lignite in the Bełchatów region is connected with the formation of various mineral waste materials: varied in origin, mineral and chemical composition and raw material properties of the accompanying minerals, ashes and slags from lignite combustion and reagipsum from wet flue gas desulphurisation installations. This paper presents the results of laboratory tests whose main purpose was to obtain data referring to the potential use of fly ashes generated in the Bełchatów Power Plant and selected accompanying minerals exploited in the Bełchatów Mine in the form of self-solidification mixtures. The beidellite clays were considered as the most predisposed for use from the accompanying minerals , due to pozzolanic and sorption properties and swelling capacity. Despite the expected beneficial effects of clay minerals from the smectite group on the self-settling process as well as the stability of such blends after solidification, the results of physical-mechanical tests (compressive strength and water repellence) were unsatisfactory. It was necessary to use Ca (OH)2, obtained from the lacustrine chalk as an activator of the self-settling process It was necessary to use lacustrine chalk as an activator of the self-solidification process. The presence of calcium will allow the formation of cement phases which will be able to strongly bond the skeletal grains. Also, the addition of reagipsum to the composition of the mixture would contribute to the improvement of the physico-mechanical parameters. The elevated SO4 2– ion in the mixture during the solidification allows for the crystallization of the sulphate phases in the pore space to form bridges between the ash and clay minerals. The use of mixtures in land reclamation unfavourably transformed by opencast mining in the Bełchatów region would result in measurable ecological and economic benefits and would largely solve the problem of waste disposal from the from the operation and processing of lignite energy.
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Abstract

Geopolymers are a new class of materials that can be synthesized using natural minerals, and waste materials. Among these substrates, the use of fly ash is desirable as it involves the conversion of a copious waste material into a useful product. The aim of the research was geopolymers synthesis from coal fly ash and biomass ash. Concentrated sodium hydroxide and sodium silicate solutions were used as activators in geopolymerisation reaction. The results show that both coal fly ash and biomass ash can be utilized as source materials for the production of geopolymers. The surface morphology and chemical composition analysis were examined for the obtained geopolymers and ashes from coal and biomass combustion by SEM-EDS methods. It was found almost total disappearance of spherical forms of grains and reduction the porosity of structure for geopolymer based on fly ash from coal combustion. While the structure of the geopolymer based ash from biomass combustion is more porous. The UV-VIS-NIR spectra were performed on the coal fly ash, biomass ash and geopolymers. They showed that the obtained geopolymers possess optical and photocatalytic properties. The similarity of the geopolymer network and the zeolite framework in relation to ion exchange and accommodation of metal ions open questions on possibilities for the application of geopolymer materials as amorphous analogues of zeolite. The FT-IR spectra analyses were used on the geopolymers before and after metals sorption. It was found that geopolymer based on ash from biomass combustion has better sorption properties compared to geopolymer based on ash from coal combustion.
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Abstract

Oxide fraction of industrial zinc ash from hot dip galvanizing was characterized in terms of composition and leaching behaviour in 10% sulfuric acid solution. Waste product contained about 68% Zn, 6% Cl, 3% Al, 1% Fe, 0.7% Si, 0.5% Pb and minor percentages of other metals (Mn, Cu, Ti etc.). It consisted mainly of zinc oxide contaminated with metallic zinc, zinc hydroxide chloride and silica. Dissolution of the metals from the material was determined as a function of solid to liquid ratio (50-150 kg/m3), temperature (20°C and 35°C) and agitation rate (300 and 900 rpm). The best results (50 g/dm3 Zn(II) at 78% zinc recovery) were obtained for 100 kg/m3 and the temperature of 20°C. Increase in the agitation rate had weak effect on the zinc yield. The final solutions were contaminated mainly by Fe(II, III) ions. Leaching of the material was an exothermic process with the reaction heat of about 800 kJ/kg.
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Abstract

Preliminary lab-scale investigations were conducted on slagging abatement in biomass-firing by fuel mixing. Three agriculture biomass fuels and olive cake were used in the experiments. Polish lignites and bituminous coals were examined as anti-sintering additives. The effects of chlorine release, potassium retention and ash sintering were examined by heating samples of biomass fuels and additives in the muffle oven and, next, firing them in the laboratory down-fired furnace at the temperature in the range of 800-1150ºC. The obtained slag samples were analysed on: chlorine and potassium content, sintering tendency and crystalline components. Among the examined coals lignite from Turów mine and bituminous coal from Bolesław Śmiały mine appeared to be the most effective in potassium retention in aluminosilicate and chlorine release from slag. Possibly the major factor of these coals which reduced ash sintering was relatively high content of kaolinite
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Abstract

The paper presents the results of the mechanical, electrical, CCSEM and XRD measurements of hard coal, conducted in simulated conditions of sintering in atmospheres of O2/CO2,. The changes of the coal ash resistivity are correlated with the content of the oxides and with the sintering temperature determined by the mechanical test and Leitz method. The SEM-EDS analysis was conducted for deposits on the probe. The changes of the measured ash samples, observed during sintering process in O2/CO2 atmosphere, were discussed in the ash microstructure point of view.
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Abstract

Due to the fact that the landfill deposition of municipal waste with the higher heating value (HHV) than 6 MJ/kg in Poland is prohibited, the application of waste derived fuels for energy production seems to be good option. There is a new combined-heat-and-power (CHP) plant in Zabrze, where varied solid fuels can be combusted. The formation of ashes originating from the combustion of alternative fuels causes a need to find ways for their practical application and demands the knowledge about their properties. Therefore, the present work is devoted to studying the co-combustion of solid recovered fuel (SRF) and coal, its impact on fly ash quality and the potential application of ashes to synthesis zeolites. The major objectives of this paper is to present the detail characteristics of ash generated during this process by using the advanced instrumental techniques (XRF, XRD, SEM, B ET, TGA). The co-combustion were carried out at 0.1 MWth fluidized bed combustor. The amount of SRF in fuel mixture was 1, 5, 10 and 20%, respectively. The focus is on the comparison the ashes depending on the fuel mixture composition. Generally, the ashes characterise high amounts of SiO2, Al2O3 and Fe2O3. It is well observed, that the chemical composition of ashes from co-combustion of blends reflects the amount of SRF addition. Considering the chemical composition of studied ashes, they can be utilize as a zeolites A. The main conclusions is that SRF can be successfully combusted with coal in CFB technology and the fly ashes obtained from coal + SRF fuel mixtures can be used to synthesis zeolites.
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Abstract

Soils that have been exposed to flood waters can be heavily polluted by inorganic and organic compounds. They are mainly compounds which appear in dissolved or suspended form flowing together with heavily laden floodwater, as well as compounds created as a result of reactions in the soil profile, mostly due to anaerobic transformation of organic matter. Heavy metals brought with flood waters are absorbed by the soil and also washed out from flood sediments by precipitation when the flood recedes. This paper presents the results of research on the effects of fertilization with ash from incineration or pyrolysis of biomass on the migration process of heavy metals (Zn, Cu, Cr, Ni, Pb, Cd, Mn) in the arable layer of soil. It has been shown that the metals in the flood sediment migrate actively in the soil profile what leads to the enrichment of the soils, also in the case of the soil fertilization with biomass ash.
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Abstract

The article presents the results of the analysis of straw obtained from ripening wheat, which was subjected to four water soaking cycles in demineralized water. The soaking was carried out under laboratory conditions at 20°C. As a result, part of mineral matter, including a significant amount of alkaline sodium and potassium salts and substances containing sulfur and phosphorus, was washed out. The process of soaking has a great impact on the chemical composition of ash obtained from water-treated straw, which increased its acidity. The Na2O content in the analyzed ash has decreased by 78%, while the K2O content has decreased by 60%. In turn, the content of water-insoluble, acid-forming SiO2 has increased by 80%. As a consequence, a positive change in the values of indices, on the basis of which the tendency of straw to slagging and deposit formation during the combustion and gasification processes is assessed, has been observed. Already after the second water soaking cycle it became apparent, based on the AI alkali index, that the examined fuel should not cause difficulties resulting from the increased intensity of use of the boiler during the combustion process. Meanwhile, the value of the BAI bed agglomeration index was considered to be safe, indicating a low possibility of bed agglomeration during the combustion or fluidized bed gasification, after the third water soaking cycle. The third of the analyzed indices, the Fu fouling index, did not indicate any tendency to deposit formation during the combustion; however, four water soaking cycles reduced its initial value by 80%. The last of the analyzed indexes, the SR, slag viscosity index did not change its value during the experiment, which, both for the raw straw and after subsequent soaking cycles, indicated that the fuel should have a low tendency to accumulate slag during the combustion process.
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Abstract

This article presents the results of the study of changes in mineral and chemical composition of artificial aggregates consisting of coal shale (a hard coal mining waste) and fluidized ashes. Such an aggregate was used for road construction. After completion of the construction works but before making the road available for public use, significant deformation of the surface in the form of irregular buckling of the asphalt layer occurred. It was excluded that this resulted from mining damage, design errors or performance mistakes, among others. A study of the materials that had been incorporated in the construction layers was undertaken in order to find the component and the mechanism responsible for the buckling of the road surface. A comparison of the mineral and chemical composition of aggregate samples collected from the embankment where the road buckled with the reference sample and samples from places without deformations showed that the bumps in the road embankment consisted of minerals that were not initially present in the aggregate. Wastes produced as a result of high temperatures (slag and power plants ashes, metallurgical wastes) are not as stable in terms of chemical and phase composition in the hypergenic environment. As a result of the processes occurring in the road embankment, anhydrite, which is the primary component of fluidized ashes, was transformed into gypsum and ettringite. As a result of contact with water CaO (present in fluidized ashes) easily changed into calcium hydroxide. As the crystallization of these minerals is expansive, it resulted in the filling of pores and, in extreme cases, in a substantial increase in the volume of the aggregate and, consequently, in the deformation of the road surface.
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Abstract

This paper presents the results of research focused on the lowering of ash flow temperature at semianthracite coal from Donbas district by means of additive (calcite) dosing. Ash fusion temperatures were set for two coal samples (A, B) and for five various states (samples of ash without any additives, with 1%, with 3%, with 5% and with 7% of the additive) in total. The macroscopicphotographic method was used for identifying all specific temperatures. Obtained outputs prove that A type coal has a lower value of sphere temperature than B type coal in the whole scope of percentage representation of the additive. The flow temperature dropped in total from 1489 °C to 1280 °C, i.e. by 14% during the test of coal of type A with 7% of the additive; while it was near 10% for coal of type B (from 1450 °C to 1308 °C). Numerical simulations of the process showed that it is not effective to add an additive with a grain size lower than 280 μm by means of wastevapour burners.
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Abstract

The article reports the results of measurements of the acoustic pressure of acoustic waves generated by acoustic dust cleaners mounted in the convection pass of the 670MWth Circulating Fluidised Bed boiler. Based on measurements carried out and the spectral analysis of recorded signals it was found that the level of acoustic pressure generated by acoustic cleaners for the frequency of 100 Hz was too low for the efficient cleaning of the heated surfaces of the reheater RH2 and superheater SH3.
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Abstract

Widely used CFD codes enable modelling of PC boilers operation. One of the areas where these numerical simulations are especially promising is predicting deposition on heat transfer surfaces, mostly superheaters. The basic goal of all simulations is to determine trajectories of ash particles in the vicinity of superheater tubes. It results in finding where on the surface the tube will be hit by particles, and what diameter and mass flow of the particles are. This paper presents results of CFD simulations for a single tube and a bundle of in-line tubes as well. It has been shown that available parameters like ash particle density, shape factor, reflection coefficients affect the trajectories in a different way. All the simulations were carried out with Fluent code of Ansys software.
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Abstract

The article concerns fly ashes generated from the combustion of hard coal and deposited on landfills. Investigation results describing fly ash taken from a combustion waste landfill are presented in the article. The investigation results indicate a possibility for combusting the coal reclaimed by separation from the fly ash and utilizing the remaining fly ash fractions.
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Abstract

Ash dieback, caused by Hymenoscyphus fraxineus, is a serious disease of common and narrow-leaved ash in Europe. The resistance of individual trees seems to be important for the maintenance of ash in European forests. In this in situ wound inoculation study, the susceptibility and differences in resistance to H. fraxineus between Fraxinus excelsior and F. angustifolia clones were assessed. Neither of the tested clones revealed total resistance to ash dieback; variety between the tested clones was observed. Differences in necroses lengths were significant between clones and between two ash species. Longer necroses were formed in F. angustifolia than in F. excelsior. Some clones exhibiting some resistance to the pathogen were identified.
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Abstract

The influence of sewage sludge torrefaction temperature on fuel properties was investigated. Non-lignocellulosic waste thermal treatment experiment was conducted within 1 h residence time, under the following temperatures: 200, 220, 240, 260, 280 and 300°C. Sawdust was used as lignocellulosic reference material. The following parameters of biochar have been measured: moisture, higher heating value, ash content, volatile compounds and sulfur content. Sawdust biochar has been confirmed to be a good quality solid fuel. High ash and sulfur content may be an obstacle for biochar energy reuse. The best temperature profile for sawdust torrefaction and fuel production for 1 h residence time was 220°C. At this temperature the product contained 84% of initial energy while decreased the mass by 25%. The best temperature profile for sewage sludge was 240°C. The energy residue was 91% and the mass residue was 85%. Higher temperatures in both cases caused excessive mass and energy losses.
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Abstract

The aim of this research was to assess the content and composition of the pollutants emitted by domestic central heating boilers equipped with an automatic underfeed fuel delivery system for the combustion chamber. The comparative research was conducted. It concerned fuel properties, flue gas parameters, contents of dust (fl y ash) and gaseous substances polluting the air in the flue gases emitted from a domestic CH boiler burning bituminous coal, pellets from coniferous wood, cereal straw, miscanthus, and sunflower husks, coniferous tree bark, and oats and barley grain. The emission factors for dust and gaseous air pollutants were established as they are helpful to assess the contribution of such boilers in the atmospheric air pollution. When assessing the researched boiler, it was found out that despite the development in design and construction, flue gases contained fly ash with a significant EC content, which affected the air quality.
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Abstract

In the paper, the technology of the production of the modified ceramic proppants used in the shale gas extracting process is described. The natural available materials and uncomplicated process to new ceramic proppants preparation were applied. The modification of the ceramic proppants based on the addition of the waste material as fly ash. The produced ceramic material in the form of granules characterized by high mechanical properties and low production costs. Moreover, the obtained good values of compressive strength and gas permeability for investigated proppants confirmed that this material has appropriate properties to be used in the hydraulic fracturing.
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