Combustion Of Biomass Fuels Research Articles

Temporal characteristic and source analysis of PM2.5 in the most polluted city agglomeration of China

The most seriously PM2.5 polluted city agglomeration has been identified by using the spatial autocorrelation model and the clustering analysis methods. The results indicated that cities which had heaviest pollution of PM2.5 were mainly located in the North China Plain (NCP) including Beijing, Tianjin, Shandong province, Henan province and Hebei province. Monthly means of PM2.5 in the most seriously polluted city agglomeration presented a U-sharp pattern, with a downward trend from January to March, basically stable but a slightly decreasing trend from April to September, and a sharply increasing trend from October to December. Serious pollution of PM2.5 in the heating season, mostly during the wintertime, might be caused by the direct emissions and secondary formation of PM2.5 accompanied by the combustion of biomass and fossil fuels for residential heating. According to the results of potential source contribution function (PSCF) calculations, the northern cities of the NCP (Beijing, Tianjing and cities of Hebei Privince) tended to be more influenced by the air masses originated locally during the heating season, while the southern cities of the NCP (cities of Shandong Province and northern Henan Province) were influenced not only by air masses originated locally, but also by air masses originated from adjacent Anhui Province and Jiangsu Province. Extraneous polluted air masses might be the main cause of the high levels of PM2.5 found in northern Henan.

Study of Indoor PM2.5 and Volatile Organic Compounds Concentration in Selected Rural and Urban Areas of Zambia

Background: High levels of household air pollution (HAP) occur in houses of many developing countries due to combustion of biomass fuels (wood, charcoal, cow dung, crop residues) in the households in open fires or inefficient stoves. Particulate Matter (PM2.5) and Volatile Organic Compounds (VOCs) are among the significant pollutants that are generated and can adversely affect the health of the exposed. Therefore, we monitored PM2.5 and VOC in selected rural and urban areas of the Copperbelt province of Zambia in order to measure the magnitude and correlates of HAP concentration levels. Methods: Indoor PM2.5 particles Results: Biomass fuel use in our study area was the dominant source of household energy for cooking. Mean indoor PM 2.5 varied greatly between households depending on fuel and kitchen type while the variations in VOC were not that much. Concentration levels for PM2.5 varied between 79 µg/m3 and 921 µg/m3, with an overall mean (SD) for daily average of 444.5 µg/m3 (170.2) while for VOC concentration levels ranged from 245 ppb to 393 ppb with an overall mean (SD) for daily average of 342 ppb (25.3). The median (Q1, Q2) indoor PM2.5 during cooking time was 501(411,686) µg/m3 and daily average 393(303,578) µg/m3 while VOC daily average was 343(320, 363) ppb concentrations in the entire study population. Conclusion: Household air pollution mean concentrations in rural and urban settings of Ndola and Masaiti excessively exceed the WHO guidelines; hence continued efforts through research and advocacy are needed to mitigate the health damaging levels of household air pollution.

Chemical-looping combustion of synthetic biomass-volatiles with manganese-ore oxygen carriers

Carbon capture and storage of CO2 from combustion of biomass, i.e., bio-energy carbon capture and storage (BECCS), makes it possible to obtain so-called negative emissions – the atmosphere is cleansed from carbon dioxide. The purpose of the present study was to investigate the suitability of different manganese ores as oxygen carriers in chemical-looping combustion of biomass fuels. For this screening study, a laboratory-scale, circulating fluidized-bed CLC system with a nominal fuel input of 300 Wth was used. The primary focus was to investigate the reactivity of these oxygen carriers towards biomass fuels, and find a reactive oxygen carrier with sufficient mechanical stability that could be suitable for large-scale chemical-looping combustion of biomass. A synthetic “biomass volatiles” gas was used to study how the different gas components react with the oxygen-carrier particles. Additional experiments were conducted with methane and a syngas. Parameter studies concerning temperature and specific fuel-reactor bed mass (bed mass per fuel thermal power in kg/MWth) were carried out. With the synthetic biomass volatiles, conversion of fuel carbon to CO2 as high as 97.6% was achieved. For a majority of the investigated ores, essentially all C2 and C3 hydrocarbons were converted, as well as a very high fraction of the CO. Reactivity towards CH4 was generally lower, but improved at higher temperatures. The resistance of the oxygen carriers towards mechanical degradation was measured in a jet-cup attrition test rig. The measured attrition was estimated as “intermediate” for four of the five tested materials, while one of the ores displayed high attrition.

Daily average exposures to carbon monoxide from combustion of biomass fuels in rural households of Haryana, India

Exposure to harmful by-products of combustion arising from the use of biomass fuels for cooking and heating in rural areas of developing countries results in poor air quality and is responsible for millions of deaths yearly. Little formal quantification and measurement of carbon monoxide (CO), one of these harmful air pollutants, have been performed in rural areas of North India. In the current study, we measured exposure to CO from cooking and heating in seven households using biomass and liquid petroleum gas (LPG) in open and closed kitchens. Exposures to CO ranged from 4.81 to 7.01, 0.20 to 1.81, and 0.02 to 0.75 mg m−3 for households cooking with biomass, cooking with LPG, and for households in which no cooking occurred, respectively. It was observed that the CO concentration in biomass-only households is much higher (78%) than in LPG-only households (14%). We found exposures in closed kitchens approximately two times higher than in open kitchens. Location of the kitchen (i.e., open vs. closed) was the most important determinant of exposure of primary cooks to CO in this geography.

Molecular Characterization of Water-Soluble Humic like Substances in Smoke Particles Emitted from Combustion of Biomass Materials and Coal Using Ultrahigh-Resolution Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.

Water-soluble humic like substances (HULIS) in smoke particles emitted from combustion of biomass materials and coal were characterized by ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry. The formulas identified were classified into four main groups: CHO, CHON, CHOS, and CHONS. The average H/C and O/C ratios are 1.13-1.33, 1.01-1.13, 1.26-1.48, 1.09-1.24 and 0.21-0.41, 0.27-0.45, 0.41-0.46, 0.44-0.61 for the CHO, CHON, CHOS, and CHONS groups, respectively. The CHO compound was the predominant component (43%-72%) of the smoke HULIS from biomass burning (BB) and coal combustion, followed by the CHON group for BB-smoke HULIS and the S-containing groups (i.e., CHOS and CHONS) for coal-smoke HULIS. These results indicate that the primary HULIS emitted from biomass burning contain a high abundance of CHON species, which appear to be made up mainly of oxidized nitrogen functional groups such as nitro compounds and/or organonitrates. The coal-smoke HULIS contained more compounds with relatively low molecular weight and high aromaticity index (AImod). They were significantly enriched in S-containing compounds with high double bond equivalent (≥4), and O/S ratios suggest that they are most likely made up of aromatic organosulfates and nitrooxy organosulfates that are usually found in polluted atmospheres. These findings imply that the primary emissions from combustion of biomass and coal fuels are potential sources of water-soluble HULIS in an atmospheric matrix and that coal combustion is an especially important source of sulfate compounds.

Association between Household Air Pollution Exposure and Chronic Obstructive Pulmonary Disease Outcomes in 13 Low- and Middle-Income Country Settings.

Forty percent of households worldwide burn biomass fuels for energy, which may be the most important contributor to household air pollution. To examine the association between household air pollution exposure and chronic obstructive pulmonary disease (COPD) outcomes in 13 resource-poor settings. We analyzed data from 12,396 adult participants living in 13 resource-poor, population-based settings. Household air pollution exposure was defined as using biomass materials as the primary fuel source in the home. We used multivariable regressions to assess the relationship between household air pollution exposure and COPD outcomes, evaluated for interactions, and conducted sensitivity analyses to test the robustness of our findings. Average age was 54.9 years (44.2-59.6 yr across settings), 48.5% were women (38.3-54.5%), prevalence of household air pollution exposure was 38% (0.5-99.6%), and 8.8% (1.7-15.5%) had COPD. Participants with household air pollution exposure were 41% more likely to have COPD (adjusted odds ratio, 1.41; 95% confidence interval, 1.18-1.68) than those without the exposure, and 13.5% (6.4-20.6%) of COPD prevalence may be caused by household air pollution exposure, compared with 12.4% caused by cigarette smoking. The association between household air pollution exposure and COPD was stronger in women (1.70; 1.24-2.32) than in men (1.21; 0.92-1.58). Household air pollution exposure was associated with a higher prevalence of COPD, particularly among women, and it is likely a leading population-attributable risk factor for COPD in resource-poor settings.

A study of environmental exposure from cooking fuel use and role of intervention

Background: Combustion of traditional biomass fuels and coal has been found to be associated with exposure to particulates and volatile organic compounds (VOCs) and cause a series of adverse health effects. Characterization-quantification of such exposure achieved so far is not optimum, and establishment of a protective mechanism with proven efficacy is the urgent need. Methods: The present study was planned to characterize exposure from fuel during cooking in a village of India and understand the effect of using intervention measure. In this study, exposure to different pollutants was examined by personal monitoring in different cooking arrangements with traditional and modified oven. Results: It is observed that level of the pollutants has lessened by several folds while cooking with modified oven in comparison to unmodified oven. Such change of pollutants levels with the use of modified oven was found to be statistically significant in cases of benzene (P Conclusions: This study highlights the exposure from indoor air pollution during cooking and promotes use of low-cost protective mechanisms to curb resulting human health adversities. This study also calls for concerted awareness generation activity among the rural population (especially women) regarding adverse health effect of cooking fuels and protective effect of installed mechanisms.

Annual Variability of Black Carbon Concentrations Originating from Biomass and Fossil Fuel Combustion for the Suburban Aerosol in Athens, Greece

The objective of this work was to assess the yearly contribution of fossil fuel combustion (BCff) and wood burning (BCwb) to equivalent black carbon (eBC) concentrations, in Athens, Greece. Measurements were conducted at a suburban site from March 2013 to February 2014 and included absorption coefficients at seven wavelengths and PM2.5 chemical composition data for key biomass burning markers, i.e., levoglucosan, potassium (K) and elemental and organic carbon (EC, OC). A well-documented methodology of corrections for aethalometer attenuation coefficients was applied with a resulting annual dataset of derived absorption coefficients for the suburban Athens’ atmospheric aerosol. The Aethalometer model was applied for the source apportionment of eBC. An optimum Ångström exponent for fossil fuel (αff) was found, based on the combined use of the model with levoglucosan data. The measured eBC concentrations were equal to 2.4 ± 1.0 μg m−3 and 1.6 ± 0.6 μg m−3, during the cold and the warm period respectively. The contribution from wood burning was significantly higher during the cold period (21 ± 11%, versus 6 ± 7% in the warm period). BCff displayed a clear diurnal pattern with a morning peak between 8 and 10 a.m. (during morning rush hour) and a second peak during the evening and night hours, due to the shallowing of the mixing layer. Regression analysis between BCwb concentrations and biomass burning markers (levoglucosan, K and OC/EC ratio) supported the validity of the results.

Effect of Unleaded Gasoline—Biofuel Blends on Exhaust Emissions

Biodiesels and biomass EtOH are currently considered the most applicable and essential biomass fuels. Furthermore, MeOH and BuOH are also attracting attention as alternatives. These fuel types can be used to reduce exhaust emissions from gasoline engines because they are renewable oxygenated bioresources. Three biofuel additives, namely, MeOH (10%, M10), EtOH (10%, E10), and BuOH (10%, B10) were used to compare the engine performance properties and exhaust gas emission levels upon combustion of mixed biomass fuels and pure petroleum fuel (clean unleaded gasoline, E0). The engine combustion temperature dropped by 4.32%, O2 emission increased by 6.67%, NOx emissions decreased by 13.46%, CO emission decreased by 44%, and hydrocarbon emissions fell by 29% if biomass fuels were used. Therefore, mixed biofuel additives and gasoline could substantially reduce engine exhaust emissions, including oxides of C and N, hydrocarbons, etc., because the biofuels contain higher oxygen contents that facilitate complete combustion.

What on Earth Have We Been Burning? Deciphering Sedimentary Records of Pyrogenic Carbon.

Humans have interacted with fire for thousands of years, yet the utilization of fossil fuels marked the beginning of a new era. Ubiquitous in the environment, pyrogenic carbon (PyC) arises from incomplete combustion of biomass and fossil fuels, forming a continuum of condensed aromatic structures. Here, we develop and evaluate 14C records for two complementary PyC molecular markers, benzene polycarboxylic acids (BPCAs) and polycyclic aromatic hydrocarbons (PAHs), preserved in aquatic sediments from a suburban and a remote catchment in the United States (U.S.) from the mid-1700s to 1998. Results show that the majority of PyC stems from local sources and is transferred to aquatic sedimentary archives on subdecadal to millennial time scales. Whereas a small portion stems from near-contemporaneous production and sedimentation, the majority of PyC (∼90%) experiences delayed transmission due to "preaging" on millennial time scales in catchment soils prior to its ultimate deposition. BPCAs (soot) and PAHs (precursors of soot) trace fossil fuel-derived PyC. Both markers parallel historical records of the consumption of fossil fuels in the U.S., yet never account for more than 19% total PyC. This study demonstrates that isotopic characterization of multiple tracers is necessary to constrain histories and inventories of PyC and that sequestration of PyC can markedly lag its production.

The influence of the inverse character of the weather on concentrations of black carbon

Black carbon (BC) is a product of incomplete combustion of fossil fuels, biomass and other fuels. The study is focused on the influence of an inverse character of the weather on the BC concentrations in the city of Ostrava during the period 2012–2016. The continuous measurement of daily concentrations of BC were performed by the portable Aethalometer, and PM10 by the DustTrak aerosol monitor. The average concentrations of BC and PM10 during the days with an inversion character of the weather, compared with the days without inversion, were increased up to 3.8 times and 3 times, respectively.

Heating Process Characteristics and Kinetics of Biomass at Different Oxygen Concentrations

Abstract Mass transfer is very important for the combustion of biomass fuels, especially pellets. The oxygen diffusion, which results in a nonuniform distribution of oxygen in the pellets, should be considered in the modeling of pellet combustion. In this study, the effect of oxygen on thermal degradation of biomass is studied by thermogravimetric (TG) experiments and then a kinetic model considering oxygen effect is developed. The fuels investigated are spruce, sophora, wheat straw, and peanut straw. TG curves are taken under different oxygen concentrations, ranging from 0 to 20 %. Oxygen concentration has little effect on the devolatilization but is critical for the behavior of char combustion. Reaction mechanism is proposed based on the observation of decomposition at different reaction conditions. The kinetic model consists of three devolatilization reactions (for cellulose, hemicellulose, and lignin) and one char combustion reaction. In the devolatilization steps, char and gas are formed as products and oxygen is not involved in the reactions. A power law dependence of oxygen is assumed for the char combustion stage. The model parameters are fitted by the experimental TG data and good agreement is observed between the experimental and modeled data at various oxygen concentrations and for different biomass fuels. It is expected that the developed kinetic model could be applied for the modeling of pellets combustion considering oxygen diffusion process.

Dissolved black carbon in the global cryosphere: Concentrations and chemical signatures

AbstractBlack carbon (BC) is derived from the incomplete combustion of biomass and fossil fuels and can enhance glacial recession when deposited on snow and ice surfaces. Here we explore the influence of environmental conditions and the proximity to anthropogenic sources on the concentration and composition of dissolved black carbon (DBC), as measured by benzenepolycaroxylic acid (BPCA) markers, across snow, lakes, and streams from the global cryosphere. Data are presented from Antarctica, the Arctic, and high alpine regions of the Himalayas, Rockies, Andes, and Alps. DBC concentrations spanned from 0.62 μg/L to 170 μg/L. The median and (2.5, 97.5) quantiles in the pristine samples were 1.8 μg/L (0.62, 12), and nonpristine samples were 21 μg/L (1.6, 170). DBC is susceptible to photodegradation when exposed to solar radiation. This process leads to a less condensed BPCA signature. In general, DBC across the data set was composed of less polycondensed DBC. However, DBC from the Greenland Ice Sheet (GRIS) had a highly condensed BPCA molecular signature. This could be due to recent deposition of BC from Canadian wildfires. Variation in DBC appears to be driven by a combination of photochemical processing and the source combustion conditions under which the DBC was formed. Overall, DBC was found to persist across the global cryosphere in both pristine and nonpristine snow and surface waters. The high concentration of DBC measured in supraglacial melt on the GRIS suggests that DBC can be mobilized across ice surfaces. This is significant because these processes may jointly exacerbate surface albedo reduction in the cryosphere.

Adoption of improved cookstoves in Pakistan: A logit analysis

About three billion people worldwide use solid fuels for cooking and space heating. This fueling practice contributes to global forest depletion and disease prevalence. To abate the environmental and health threats caused by the inefficient burning of biomass fuels, large-scale initiatives were undertaken globally for the dissemination of fuel-saving and energy-efficient stoves, known as improved cookstoves (ICS). This paper examines the adoption of ICS in northwest Pakistan by using a logit analysis. The results show that the education of the respondent, number of working household members, and total income of the household had significant effects on the adoption of ICS. Conversely, the age of the respondent and possession of land did not exhibit any significant influence on adoption. The overall model was significant with p < 0.001 which reveals that the selected socioeconomic variables have a statistically significant relationship with the adoption of ICS. The paper concludes that the efforts to improve health and environmental conditions may be more successful if ICS programs take the socioeconomic, contextual, and market related factors into account.

Comparison of in vitro toxicological effects of biomass smoke from different sources of animal dung

Worldwide, over 4 million premature deaths each year are attributed to the burning of biomass fuels for cooking and heating. Epidemiological studies associate household air pollution with lung diseases, including chronic obstructive pulmonary disease, lung cancer, and respiratory infections. Animal dung, a biomass fuel used by economically vulnerable populations, generates more toxic compounds per mass burned than other biomass fuels. The type of animal dung used varies widely depending on local agro-geography. There are currently neither standardized experimental systems for dung biomass smoke research nor studies assessing the health impacts of different types of dung smoke. Here, we used a novel reproducible exposure system to assess outcomes related to inflammation and respiratory infections in human airway cells exposed to six different types of dung biomass smoke. We report that dung biomass smoke, regardless of species, is pro-inflammatory and activates the aryl hydrocarbon receptor and JNK transcription factors; however, dung smoke also suppresses interferon responses after a challenge with a viral mimetic. These effects are consistent with epidemiological data, and suggest a mechanism by which the combustion of animal dung can directly cause lung diseases, promote increased susceptibility to infection, and contribute to the global health problem of household air pollution.

Towards the isolation and estimation of elemental carbon in atmospheric aerosols using supercritical fluid extraction and thermo-optical analysis

Air-starved combustion of biomass and fossil fuels releases aerosols, including airborne carbonaceous particles, causing negative climatic and health effects. Radiocarbon analysis of the elemental carbon (EC) fraction can help apportion sources of its emission, which is greatly constrained by the challenges in isolation of EC from organic compounds in atmospheric aerosols. The isolation of EC using thermo-optical analysis is however biased by the presence of interfering compounds that undergo pyrolysis during the analysis. EC is considered insoluble in all acidic, basic, and organic solvents. Based on the property of insolubility, a sample preparation method using supercritical CO2 and methanol as co-solvent was developed to remove interfering organic compounds. The efficiency of the method was studied by varying the density of supercritical carbon dioxide by means of temperature and pressure and by varying the methanol content. Supercritical CO2 with 10% methanol by volume at a temperature of 60 °C, a pressure of 350 bar and 20 min static mode extraction were found to be the most suitable conditions for the removal of 59 ± 3% organic carbon, including compounds responsible for pyrolysis with 78 ± 16% EC recovery. The results indicate that the method has potential for the estimation and isolation of EC from OC for subsequent analysis methods and source apportionment studies.

A health intervention or a kitchen appliance? Household costs and benefits of a cleaner burning biomass-fuelled cookstove in Malawi

Pneumonia is the leading cause of mortality for children under five years in sub-Saharan Africa. Household air pollution has been found to increase risk of pneumonia, especially due to exposure from dirty burning biomass fuels. It has been suggested that advanced stoves, which burn fuel more efficiently and reduce smoke emissions, may help to reduce household air pollution in poor, rural settings.This qualitative study aims to provide an insight into the household costs and perceived benefits from use of the stove in Malawi. It was conducted alongside The Cooking and Pneumonia Study (CAPS), the largest village cluster-level randomised controlled trial of an advanced combustion cookstove intervention to prevent pneumonia in children under five to date. In 2015, using 100 semi-structured interviews this study assessed household time use and perceptions of the stove from both control and intervention participants taking part in the CAPS trial in Chilumba. Household direct and indirect costs associated with the intervention were calculated.Users overwhelming liked using the stove. The main reported benefits were reduced cooking times and reduced fuel consumption. In most interviews, the health benefits were not initially identified as advantages of the stove, although when prompted, respondents stated that reduced smoke emissions contributed to a reduction in respiratory symptoms. The cost of the stove was much higher than most respondents said they would be willing to pay.The stoves were not primarily seen as health products. Perceptions of limited impact on health was subsequently supported by the CAPS trial data which showed no significant effect on pneumonia. While the findings are encouraging from the perspective of acceptability, without innovative financing mechanisms, general uptake and sustained use of the stove may not be possible in this setting. The findings also raise the question of whether the stoves should be marketed and championed as ‘health interventions’.

An overview of the Effect of Biomass in-door-air Pollution on Household Members

Worldwide statistics show that 2.4 billion people depend on biomass fuel for cooking and heating. Biomass are plant materials and animal waste used especially as source of fuel. Typically, burned in open fire or inefficient stoves without appropriate ventilation, biomass fuels emit substantial amounts of health damaging pollutants leading to high level of exposure. In developing countries the level is at least 10-20 times higher than World Health Organisation (WHO) guidelines. Women and young children who spend many hours daily near the fire are the most exposed. A growing body of literature implicates in-door air pollution from biomass fuel as a risk factor for the development of Chronic Obstructive Pulmonary Disease (COPD) and Lung cancer in women and Acute Respiratory Infections (ARI) in young children.4-8 About two billion people have no access to modern energy and a billion have it only sporadically. Household members especially women and children in rural settlements collect all kinds of materials that are hazardous for their source of household energy. This is peculiar to the rural populations and more so the poor communities. Biomass fuels are at the low end of the energy ladder in terms of combustion efficiency and cleanliness. Smoke from biomass combustion produces a large number of health damaging air pollutants including inhalable particulate matter, Carbon Monoxide (CO), Nitrogen oxides, Formaldehyde, Benzene, 1,3 Butadiene, Polycyclic aromatic hydrocarbons, and many other toxic organic compounds. In developing countries, where large proportions of households rely on biomass fuels for cooking and space heating, concentrations of these air pollutants tend to be highest indoors. The fuels are typically burned in simple, inefficient, and mostly unvented household cook stoves, which, combined with poor ventilation, generate large volumes of smoke indoors. Moreover, cook stoves are typically used for several hours each day at times when people are present indoors, resulting in much higher exposure to air pollutants than from out-door sources. More than three billion people or half the world's populations, cook in their homes using traditional fire and stoves, burning biomass fuels such as woods and crop waste materials. Household members breathe in the toxic fumes from these cooking fires daily.

Life cycle human health and ecosystem quality implication of biomass-based strategies to climate change mitigation

Exposure to air pollution claimed the lives of about seven million people worldwide in 2010, largely from combustion of solid biomass fuels. Bioenergy is an alternative renewable source which can mitigate a climate change. Little is known about the human health and ecosystem effects of bioenergy, mainly in the electricity sector. This research applied a life cycle assessment approach to examine the human health and ecosystem effects of four bioenergy pathways: direct combustion of wood biomass, direct combustion of forest residue, direct combustion of pellets, and biomass integrated gasification and combined cycle (BIGCC). All pathways showed some variability of impacts; therefore, no single bioenergy pathway was the best absolute option. With the exception of the slightly higher human health impact, BIGCC has the least impact for all impact categories. However, all bioenergy systems implied lower ecosystem impact but higher human health impact as compared to climate change impact. Electricity generation from wood-biomass would improve the environmental sustainability of Alberta's electricity grid system because it reduces the human health and ecosystem impacts, as compared to the existing electricity production mix of the province.

Time-Dependent Crack Layer Formation in Quartz Bed Particles during Fluidized Bed Combustion of Woody Biomass

Bed agglomeration during combustion and gasification of woody biomass fuels in quartz beds has been frequently studied, and chemical mechanisms responsible for bed agglomeration have been suggested. However, few studies have focused on the bed material deposition on walls, in cyclones, and return legs in fluidized bed combustion. Part of these bed material depositions originates from sticky fragments of alkali-rich silicates formed after crack formation in older quartz bed particles. The crack layer formation in quartz bed particles in fluidized bed combustion of woody biomass was therefore investigated by collecting bed material samples of different ages from full-scale bubbling and circulating fluidized bed facilities. Scanning electron microscopy/energy-dispersive spectroscopy was used to analyze the crack morphology and composition of the layer surrounding the cracks. For quartz bed particles with an age of some days, a crack in the quartz bed particle was observed in connection to the irregular inter...