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This short review article explores the advancement, challenges, and prospects of boron-laden solid fuel for ramjet. The energetic aspect of boron combustion is well known, but the complications associated with its efficient combustion persist and must be overcome to harness its potential completely. The strategies like coating, adding additives, and utilizing boron nanoparticles, which may improve its combustion performance, are widely studied. The latest development in advanced rocket propulsion systems, i.e., using a hybrid fuel-based gas generator for ducted rockets or air augmentation of hybrid rockets, seems a feasible idea; as it can provide two-stage combustion, which may significantly promote and improve the combustion performance of boron hence the specific impulse. Since it utilizes hybrid fuel, it retains its advantages of it as well as its drawbacks. To mitigate these drawbacks, various strategies/suggestions are briefly discussed here. A fundamental aspect of boron combustion must be fully understood and addressed for its applications in advanced propulsion systems.

Although current EU regulations, such as EU Directive 2015/1189 on the eco-design of solid fuel boilers and Directive 2015/1188, in accordance with the Machinery Directive 2006/42/EC, require manufacturers to meet specific emission requirements for CE marking, the routine and regular onsite testing of household heating appliances is still not mandatory in many EU countries. This research endeavour addressed this gap by evaluating the effectiveness of the Bacharach method as a rapid and cost-effective tool for assessing flue gas quality, particularly in terms of particulate matter mass concentration. This study also compared the results of the Bacharach method with those obtained from two commercially available portable analysers. The research outcomes demonstrate that the Bacharach method, in combination with an innovative evaluation approach, offers a viable solution, enabling the swift and economical assessment of flue gas quality with the primary objective of determining the boiler class according to the limits specified by standard EN 303-5 under operating conditions. The modified Bacharach method for measuring TSP in solid fuel-fired boilers provides qualitatively similar results to the commercially used SM500 and STM225 instruments. The modified Bacharach methodology was primarily developed for comparison to the boiler class 3 limit (i.e., 125 and 150 mg/m3). The study revealed that the modified Bacharach method, when applied to biomass-based boilers, exhibited higher accuracies in the case of classification into classes 3 and 4, whereas fossil fuel-based boilers demonstrated higher accuracy in the case of class 5 limits.

This study explores the hydrothermal carbonization (HTC) process applied to the exhausted chestnut produced by the tannin extraction industry, utilizing process water recirculation to enhance the efficiency and sustainability of the conversion process. Tannin extraction from wood typically involves hot water treatment, leaving behind residual wood biomass known as exhausted wood. These by-products maintain their renewable properties because they have only been exposed to hot water under a high pressure, which is unlikely to cause major alterations in their structural components. Hydrothermal treatment was carried out at temperatures of 220 °C and 270 °C for 1 h, with process water being recirculated four times. This investigation focused on analyzing the effects of recirculation on the yield and fuel properties of hydrochar, as well as characterizing the combustion behavior of the obtained hydrochar. The results indicated that recirculation of process water led to improvements in both the mass and energy yields of hydrochar. The mass yield of the hydrochar samples increased by 5–6%, and the ERE of the hydrochar samples increased by 5–8% compared to the HTC reference sample. However, alterations in the combustion characteristics were observed, including decreases in ignition temperature and combustion reactivity. The results indicate that, with PW recirculations, the combustion index decreased by about 14% and 18% for 220 °C and 270 °C, respectively. Overall, this research demonstrates the potential of utilizing HTC on chestnut tannin residue with process water recirculation to produce stable solid fuel and provides insights into the combustion behavior of the resulting hydrochar.

(1) Background: Water and solid fuel collection and transport are domestic duties for millions of households across the globe. People in areas with limited or no access to safely managed sources of water and household energy must fetch these resources on a frequent basis. The health, gender, and economic impacts associated with water and solid fuel collection labor have not been systematically reviewed. (2) Methods: Studies were identified through database searches and included using a list of inclusion and exclusion criteria. Studies were summarized and grouped into one of eight thematic categories. (4) Conclusions: The findings suggest that a diverse and heavy health burden is associated with water and solid fuel collection and transport. The literature also suggests that the provision of safely managed and accessible water and improved fuel options can mitigate these negative outcomes. Filling research gaps and utilizing results to guide policy and funding would likely be an effective way to ensure low- and middle-income countries are not left behind as the world strives to meet the sustainable development goals.

Abstract Background Solid fuels are still widely used for cooking in rural China, leading to various health implications. Yet, studies on household air pollution and its impact on depression remain scarce. Using baseline data from the China Kadoorie Biobank (CKB) study, we aimed to investigate the relationship between solid fuel use for cooking and depression among adults in rural China. Methods Data on exposure to household air pollution from cooking with solid fuels were collected and the Chinese version of the World Health Organization Composite International Diagnostic Interview short-form (CIDI-SF) was used to evaluate the status of major depressive episode. Logistic regression analysis was performed to investigate the association between solid fuel use for cooking and depression. Results Amongst 283,170 participants, 68% of them used solid fuels for cooking. A total of 2,171 (0.8%) participants reported of having a major depressive episode in the past 12 months. Adjusted analysis showed that participants who had exposure to solid fuels used for cooking for up to 20 years, more than 20 to 35 years, and more than 35 years were 1.09 (95% CI: 0.94–1.27), 1.18 (95% CI: 1.01–1.38), and 1.19 (95% CI: 1.01–1.40) times greater odds of having a major depressive episode, respectively, compared with those who had no previous exposure to solid fuels used for cooking. Conclusion The findings highlight that longer exposure to solid fuels used for cooking would be associated with increased odds of major depressive episode. In spite of the uncertainty of causal relationship between them, using solid fuels for cooking can lead to undesirable household air pollution. Reducing the use of solid fuels for cooking by promoting the use of clean energy should be encouraged.

BACKGROUND AND OBJECTIVES: The decreasing availability of fossil fuels requires the adoption of renewable energy sources that facilitate the mitigation of greenhouse gas emissions. Meeting Indonesia’s goal of achieving a 23 percent mixed energy composition by 2025 through co-firing demands a substantial increase in the availability of renewable energy sources. Bamboo is a valuable biomass resource because of its fast growth rate and potential for energy production. Innovative processes like torrefaction are necessary to improve the quality of biomass due to its challenging low density and hydrophilic properties. The objective of this study is to evaluate the characteristics of torrefied bamboo pellets made from Gigantochloa pseudoarundinacea by using a fixed counter-flow multi-baffle reactor. This study aims to investigate the properties and viability of torrefied G. pseudoarundinacea pellets for solid fuel applications to fill existing knowledge gaps about this technology’s potential.METHODS: A fixed counter-flow multi-baffle reactor was used to torrefy G. pseudoarundinacea bamboo pellets. The baffles in the reactor column held the pellets, while hot gas flowed through them. Torrefaction was conducted at 280 degrees Celsius with a 3–5 minutes resident time, and the gas flow rate was 4.25 cubic meters per minute. Torrefied pellets at the column bottom were counted as the first cycle. Three cycles of torrefaction were used, and each cycle was evaluated. The second and third cycles used torrefied pellets from the first and second cycles. The physical, chemical, and bioenergetic properties of the pellets before and after torrefaction were evaluated.FINDINGS: The bamboo pellets’ physical, chemical, and thermal properties changed significantly after torrefaction. Torrefaction at 285 degrees Celsius produced 78.5 percent of the production yield, according to thermogravimetric and derivative thermogravimetric analyses. Lightness, red/green, and yellow/blue chromaticity decreased, indicating darker, better solid fuel pellets. Torrefaction in the third cycle reduced moisture content by 99.8 percent. The lower moisture content reduced fungal growth, and improvinged biomass transport and storage. Torrefaction also raised the bamboo pellets’ calorific value and physical and mechanical properties. The highest calorific value of 21.62 megajoules per kilogram was obtained after the third cycle of torrefaction, and it was 16.6 percent higher than that of raw pellets. Torrefaction improved pellet grindability and combustion by decreasing density and compressive strength. Torrefaction increased ash, volatile matter, and fixed carbon. The ultimate analysis showed increased carbon and reduced nitrogen, hydrogen, and oxygen, improving solid fuel quality, energy density, and combustion emissions. According to a Fourier-transform infrared analysis, torrefaction caused extractive and hemicellulose degradation and lignin increase. The chemical analysis showed that temperature and residence time degraded hemicellulose and increased lignin in the torrefied pellets.CONCLUSION: The torrefaction process using a fixed counter-flow multi-baffle reactor demonstrated the enhanced properties of G. pseudoarundinacea bamboo pellets for their application as solid fuel. The study’s findings contribute to the comprehension of torrefaction and the enhancement of conditions for producing superior biomass products. These findings have implications for exploring the potential applications of torrefaction in diverse industries and energy sectors.

The objectives of this investigation were to elucidate the potential use of metal oxide-rich sewage sludge obtained from the treated brewery wastewater into a value-added solid fuel via co-hydrothermal carbonization process (co-HTC). Two residue biomass including spent coffee grounds and bagasse were supplied as co-combustion. The effects of sewage sludge and biomass addition on fuel properties were evaluated to optimize the best condition for biocoal-liked production. The chemical composition and mineral phase of solid product were further analyzed. Combustion kinetics analysis including activation energy (E) and pre-exponential factor (A) were derived from thermogravimetric analysis. It was found that the addition of coffee grounds and bagasse enhanced the fuel properties of the solid products, remarkably increasing high heating value (HHV) along with a low ash content, providing an increased fuel ratio of 0.34 – 1.01 and higher HHV as 14.29 – 22.19 MJ/kg. The highest rate of energy recovery was achieved when combining 75 wt% sewage sludge with 25 wt% spent coffee grounds. A substantial decrease of H/C and O/C atomic ratios was distinguished after bagasse addition compared to commercial lignite coal. It was also noticed that the relationship between the sewage sludge and biomass feedstocks during co-HTC is synergistic by increasing the amount of oxidative carbon during the char combustion stage and enhancing the degree of thermal stability. Moreover, it was also emphasized that during co-HTC some carbon and inorganic contents of sludge and lignocellulosic biomass were partially transferred into a liquid phase confirmed by TOC and ICP-OES analyses. A heavy metal leaching toxicity in a liquid product was also determined according to the USA-EPA standard. The combustion reactivity was improved, especially combustion reactivity of the biomass-sewage sludge-derived hydrochar. Interestingly, the hydrochar product was anticipated to possess enhanced safety and stability. Moreover, the co-combustion of hydrochar and coal improved the devolatilization properties and ignition of coal. This strategy revealed that co-hydrothermal process with biomass is a prospective approach to increase the value-added of sewage sludge feedstock as bicoal-like solid fuel.

In this study, energetic properties of cellulose (CL) and lignin (LN) were enhanced through torrefaction (TF) and hydrothermal carbonization (HTC) processes. TF was conducted at 200 to 300 °C for 30 min under 100 mL/min CO2. HTC was conducted at 180 to 220 °C for 30 min using liquid fraction (LF) recirculation. The derived biochar and hydrochar were investigated in the parameters of mass yield, proximate and ultimate analysis, energetic properties, thermal decomposition properties, surface chemical functional groups, and surface morphology. TF affected CL and LN properties rather than HTC. Energetic properties of CL and LN were greatly enhanced using TF. On the other hand, HTC affected the energetic properties of CL and LN marginally, and the effect of LF recirculation on hydrochar energetic properties could have been negligible. CL and LN chars with maximum HHV improvement (0.73 and 0.13) and energy yield (161.61 and 96.37%) could be derived through TF. The O/C and H/C ratios of the biochar were decreased and found to be similar to those of lignite and sub-bituminous coal. In addition, HHV of CL hydrochar was much lower than that of CL biochar, while HHV of LN hydrochar could be comparative with LN biochar. These results suggested that TF constitutes an outstanding technology for producing char fuel from lignocellulosic biomass. LF recirculation during the HTC process could enhance its economic feasibility and environmental friendliness. Biomass with high LN content could serve as a promising material for producing solid fuel. [ABSTRACT FROM AUTHOR]

In the wake of economic and population growth, increased wastewater production poses a challenge related to sewage sludge treatment, which is problematic given its high moisture content, amount, and hazardous characteristics. This study focuses on the hydrothermal carbonization of sewage sludge to produce carbonous material–hydrochar, which may be an alternative to fossil fuels. The effect of process parameters, namely, temperature (180, 240, 300 °C) and duration time (30, 90, 180 min), on hydrochar properties (proximate and ultimate analysis, heating values) and process performance were studied. Obtained results indicate and confirm that hydrothermal carbonization, especially temperature increase, improves the fuel properties of carbonized sewage sludge. The highest low heating value was obtained for hydrochar derived at 300 °C in 180 min (~23 MJ × kg−1). The highest energy gain was noted for hydrochar derived at 240 °C in 180 min (~23%). As well as relatively high mass and energy yield in comparison to other hydrochars, these parameters are considered the most favorable for sewage sludge hydrothermal carbonization. However, high energy consumption (over 1300 kJ × g−1) suggests that more research on the process's economical efficacy is required. [ABSTRACT FROM AUTHOR]

The Sustainable Development Goal (SDG) 7 targets universal access to affordable, reliable, and modern energy services by 2030. Modern or clean energy is perceived to be the golden thread that connects economic growth, human development, and environmental sustainability. However, one third of the world's population still uses solid fuels for cooking, endangering human health, and the environment. This paper, therefore, analyses demographic, socio‐economic, and housing characteristics that affect the fuel choice for cooking. Further, it identifies how SDG 4 (quality education) and SDG 6 (clean water) create synergies with SDG 7 (clean energy). The data are obtained from the four waves of the Sri Lankan Households Income and Expenditure Survey, covering more than 79,000 households. The random‐effects panel multinomial logit results reveal that household income, wealth, marital status and education of the head, age and education of the spouse, household size, number of children, housing characteristics, and residential sector are vital in selecting clean fuel for cooking. Furthermore, advanced sustainability analysis shows SDG 4 and 6 have a strong synergistic effect on SDG 7. Policymakers can use the findings to prioritise educational, water, and sanitation programmes in national policies aimed at enhancing the use of clean cooking fuel and technologies to meet SDG 7 by 2030. [ABSTRACT FROM AUTHOR]

Household air pollution (HAP) is associated with the development of lung cancer, yet few studies investigated the exposure patterns and joint associations with tobacco smoking. In our study, we included 224 189 urban participants from China Kadoorie Biobank (CKB), 3288 of which diagnosed with lung cancer during the follow‐up. Exposure to four HAP sources (solid fuels for cooking/heating/stove and environmental tobacco smoke exposure) was assessed at baseline. Distinct HAP patterns and their associations with lung cancer were examined through latent class analysis (LCA) and multivariable Cox regression. A total of 76.1% of the participants reported regular cooking and 52.2% reported winter heating, of which 9% and 24.7% used solid fuels, respectively. Solid fuel heating increased lung cancer risk (Hazards ratio [HR]: 1.25, 95% confidence interval [CI]: 1.08‐1.46). LCA identified three HAP patterns; the "clean fuel cooking and solid fuel heating" pattern significantly increased lung cancer risk (HR: 1.25, 95% CI: 1.10‐1.41), compared to low HAP pattern. An additive interaction was observed between heavy smoking and "clean fuel cooking and solid fuel heating" (relative excess risk [RERI]: 1.32, 95% CI: 0.29‐2.47, attributable proportion [AP]: 0.23, 95% CI: 0.06‐0.36). Cases resulting from solid fuel account for ~4% of total cases (population attribute fraction [PAF]overall: 4.31%, 95% CI: 2.16%‐6.47%, PAFever smokers: 4.38%, 95% CI: 1.54%‐7.23%). Our results suggest that in urban China, solid fuel heating increased the risk of lung cancer, particularly among heavy smokers. The whole population could benefit from cleaner indoor air quality by reducing using solid fuels, especially smokers. [ABSTRACT FROM AUTHOR]

The resource utilization of agricultural and forestry wastes is of great significance for low-carbon environmental protection and the transformation of China's energy structure. The way of the fuel utilization of agricultural and forestry wastes was introduced in this paper, and the molding process of biomass solid briquette was summarized. The research status of the factors affecting the briquetting quality and the binders used in the carbonization briquetting and other fields were also discussed. The development trend of the performance of biomass solid briquettes was prospected, and the existing problems of biomass solid briquettes were pointed out and suggestions for improvement were also put forward. [ABSTRACT FROM AUTHOR]

[Display omitted] • Acidic hydrochar enhances dechlorination of waste PVC during co-HTT. • co-HTT of waste PVC improves energy content of HTT solid residues. • co-HTT solids showed higher ignition temperature and lower burnout temperatures. • co-HTT solids had low slagging, fouling and alkali indices. In this study, the chlorine mitigation from waste polyvinyl chloride (WPVC) during high temperature co-hydrothermal treatment (co-HTT) and the properties of the generated solid products were assessed. WPVC was co-fed with acidic hydrochar (AHC), which was produced via hydrothermal carbonization of pineapple waste in the presence of citric acid water solution. High temperature co-HTT experiments were performed at 300–350 °C, 0.25–4 h of reaction time, and 0–20 wt% AHC loading. Co-HTT solid products (co-HTT_SP) were characterized via proximate analysis, ultimate analyses, combustion analysis, and ash analysis. The results show that the addition of 5% AHC enhances the dechlorination efficiency (DE) of WPVC from 89.35% to 97.66% at 325 °C and 0.5 h. The highest DE, reaching 99.46%, was achieved at 350 °C and 1 h in the presence of 5 wt% AHC. Furthermore, loading 5% AHC improved the higher heat value (HHV) of the solid products from 23.09 to 31.25 MJ/kg at 325 °C and 0.5 h. The maximum HHV (34.77 MJ/kg) of a solid product was achieved at 350 °C, 4 h, in the presence of 5 wt% of AHC. The co-HTT solids shown low slagging indices, fouling indices, alkali indices, and medium chlorine contents. These findings support the viability of WPVC conversion into clean solid fuel via co-HTT. [ABSTRACT FROM AUTHOR]

Spent mushroom substrate (SMS), often disregarded as waste despite its abundance in organic matter and mineral micronutrients, has emerged as a valuable resource for diverse applications. While Europe and Asia have witnessed extensive research in this field over the past decade, Ukraine’s exploration remains limited. This study conducts a thorough investigation into SMS recycling and reutilization over a 4-year period. Employing experimental and comparative methods, this research unveils compelling insights into the potential of SMS for reintroduction into the primary production cycle and secondary activities. The main conclusions reveal the success of SMS valorization in the production of additives, fertilizers, and alternative fuels. Furthermore, the application of SMS in agroecosystems significantly enhances the soil biological activity. The integration of these methods into production chains not only yields economic benefits for companies but also fosters environmental stewardship, aligning with waste-free practices and the principles of bioeconomy and sustainability.

The aim of this study was the characterization and evaluation of applicability as a soil amendment of biochar derived from rose pruning waste at different pyrolysis temperatures (200–500 °C) and process durations (20–60 min). The biochar properties were compared to the raw material. The biochars produced at 300 °C for 40 and 60 min demonstrated the best fuel properties. These variants showed high energy gain rates (77.6 ± 1.5% and 74.8 ± 1.5%, respectively), energy densification ratios (1.35 ± 0.00 and 1.37 ± 0.00, respectively), high heating values (24,720 ± 267 J × g−1 and 25,113 ± 731 J × g−1, respectively), and relative low ash contents (5.9 ± 0.5% and 7.1 ± 0.3%, respectively). Regarding fertilizer properties, such as pH value, ash content, heavy metal content, and pollutant elution, the biochars showed better qualities than the raw material. All tested biochar did not exceed the permissible values for heavy metals, including Cr, Cd, Ni, and Pb. The most optimal properties for soil amendments were noted for biochar variants of 400 °C for 40 min, 450 °C for 20 min, and 500 °C for 20 min. Generally, biochars produced at temperatures ≥400 °C did not inhibit root elongation, except for the material produced at 450 °C for 60 min (4.08 ± 23.34%). Biochars obtained at ≥300 °C showed a positive impact on seed germination (86.67 ± 18.48–100 ± 24.14%).

Solid biofuels and Internet of Things (IoT) technologies play a vital role in the development of smart cities. Solid biofuels are a renewable and sustainable source of energy obtained from organic materials, such as wood, agricultural residues, and waste. The integration of IoT technology with solid biofuel classification can improve the performance, quality control, and overall management of biofuel production and usage. Recently, machine learning (ML) and deep learning (DL) models can be applied for the solid biofuel classification process. Therefore, this article develops a novel solid biofuel classification using sailfish optimizer hybrid deep learning (SBFC-SFOHDL) model in the IoT platform. The proposed SBFC-SFOHDL methodology focuses on the identification and classification of solid biofuels from agricultural residues in the IoT platform. To achieve this, the SBFC-SFOHDL method performs IoT-based data collection and data preprocessing to transom the input data into a compatible format. Moreover, the SBFC-SFOHDL technique employs the multihead self attention-based convolutional bidirectional long short-term memory model (MSA-CBLSTM) for solid biofuel classification. For improving the classification performance of the MSA-CBLSTM model, the SFO algorithm is utilized as a hyperparameter optimizer. The simulation results of the SBFC-SFOHDL technique are tested and the results are examined under different measures. An extensive comparison study reported the betterment of the SBFC-SFOHDL technique compared to recent DL models. [ABSTRACT FROM AUTHOR]

Conversion of waste wood containing urea–formaldehyde resin (WW-UF) into solid fuel with lower nitrogen content and better fuel property through the hydrothermal carbonization (HTC) process was studied. With the increase of HTC temperature from 180 to 260 °C, the mass yield and energy yield of the hydrochar decreased from 81.2 to 38.7% and from 81.6 to 62.3%, respectively, while the higher heating values (HHV) of the hydrochar increased from 19.2 to 27.1 MJ/kg. Due to the hydrolysis of urea–formaldehyde resin into urea, the denitrogenation efficiency could reach over 80% at 180 °C. However, the denitrogenation efficiency decreased at elevated HTC temperature because of the condensation/polymerization of urea with carbohydrate derivatives. The combustion and pelletization behaviors of the hydrochar were all improved compared to that of the raw WW-UF. FT-IR spectra confirmed that the UF resin and hemicellulose in the WW-UF could be hydrolyzed at 180 °C, but carbonization of cellulose occurred with HTC temperature over 240 °C. The process water was analyzed by LC–MS/MS to confirm that the mono-saccharides, carboxylic acids, carbocyclic compounds, O-heterocyclic compounds, and N-heterocyclic compounds were presented in process water. The study confirmed that hydrothermal carbonization could be one promising method to covert the WW-UF into clean and efficient solid fuel. [ABSTRACT FROM AUTHOR]

Shrimp shell is a popularly consumed seafood around the globe which generates a substantial quantity of solid wet waste. Hydrothermal carbonization (HTC) could be a viable pathway to convert wet shrimp shell waste into energy-dense hydrochar. The present study aims to assess the fuel properties, physicochemical attributes, and combustion properties of shrimp shell hydrochar generated with a wide range of HTC temperatures (110–290 °C). Results showed that a rise in carbonization rate results in a decline in mass yield to as low as 25.7% with the increase in HTC temperature. Thermogravimetric analysis indicates shrimp shell hydrochars to be more thermally stable than raw dried feedstock. Results from the bomb calorimeter report a maximum HHV of 27.9 MJ/kg for SS-290, showing a 13% increase in energy densification compared to raw shrimp shell. The slagging and fouling indices determined for the hydrochars further assisted in addressing the concern regarding increasing ash content changing from 17.0% to 36.6%. Lower ratings of the slagging index, fouling index, alkali index, and chlorine content for hydrochars at higher temperature indicate the reduced probability of reactor fouling during combustion. The findings of the analysis demonstrate that HTC is a promising approach for transforming shrimp shell waste into a potential fuel replacement. [ABSTRACT FROM AUTHOR]

The combustion of solid fuels is a complex feedback loop, coupling the decomposition of the solid fuel into volatile gases with the gas-phase combustion which is responsible for the heat flux that drives decomposition. This study aims to explore the combustion of a solid fuel, hydroxyl-terminated polybutadiene (HTPB), with different mixtures of oxygen and nitrogen in an opposed-flow burner (OFB) configuration to better understand these coupled processes. An experimental OFB setup is described, which utilizes a nichrome wire and linear variable differential transformer (LVDT) to capture regression rate and shadowgraph imaging to measure flame thickness. Experimental measurements are compared with results from a complimentary one-dimensional opposed-flow combustion model with a pyrolyzing solid fuel boundary condition that conserves mass, species, and energy at the solid-gas interface. The oxidizer mass flux, ratio of oxygen to nitrogen, and separation distance of the fuel and oxidizer are varied to understand their influence on the combustion process and subsequently their effect on the regression rate. In numerical results, fuel regression rate increases when oxygen mole fraction or mass flux increase, or when separation distance decreases. Experimental regression rates and flame thicknesses are compared to simulated results. Though the actual values do not agree exactly, numerical and experimental results are reasonably close and present similar trends. These results demonstrate the utility of simple optical diagnostics in measuring OFB flames and provide a starting point for future opposed-flow combustion model improvements. [ABSTRACT FROM AUTHOR]

Nigeria has the potential to generate 12,522 MW of electricity, but can only dispatch 4000 MW, which is insufficient for a population of over 200 million people as of 2022. Therefore, Nigerians use solid fuels including firewood and charcoal as an alternative to insufficient electricity for domestic use. The consumption of firewood and charcoal in Nigeria is estimated at 23,745,458 tons and 4,828,689 tons, respectively in 2021, by far the most consumed domestic solid fuel sources in Nigeria. Although there are domestic solid fuel alternatives, such as dung, agricultural residues and coal, to firewood and wood charcoal, their sustainable adoption has been slow in Nigeria, indicating that there is insufficient knowledge of domestic solid fuel sources. This requires a review focused on assessing Nigeria's national sources of solid fuels. This article presents an overview of the sources of domestic solid fuels in Nigeria, an exploration of different types of firewood and charcoal studies, the impact of solid fuels on climate change and the environment, health risks associated with solid fuel and biomass briquettes and pellets as domestic solid fuel alternatives to charcoal and firewood. The continued production and use of firewood and wood charcoal as domestic solid fuel sources encourage deforestation, desertification and greenhouse gas emission, which in turn pose a threat to a sustainable environment and good health. It is necessary to limit the felling of trees for firewood and charcoal production to curtail their negative impacts on the health of users and the environment. This review covered the thermal, mechanical and physical properties of briquette and pellet fuels as substitutions for firewood and charcoal. It was shown that employing briquettes and pellets as a source of solid fuel in the home will lessen the negative impacts that these fuels have on users' health, the climate and the environment. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has led to the increased use of disposable face masks worldwide, resulting in a surge of potentially infectious waste. This waste must be safely managed and disposed of to prevent the spread of the virus. To address this issue, a preliminary study explored the use of hydrothermal carbonization (HTC) as a potential method for converting surgical mask waste into value-added carbonaceous materials. The HTC treatments were conducted at 220 °C for 3 h with or without the addition of acetic acid. The resulting hydrochar was characterized using several techniques, including thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and N2-physisorption analyzers. The study found that the masks formed a melt with reduced mass (−15%) and volume (up to −75%) under the applied conditions. The carbon content and higher heating value (HHV) of the produced hydrochars were higher than those of the original masks (+5%). Furthermore, when acetic acid was added during the HTC experiment, a new crystal phase, terephthalic acid, was produced. This acid is a precursor in surgical mask production. The study suggests that hydrothermal carbonization could potentially achieve sanitization and volume reduction in non-renewable and non-biodegradable surgical masks while also producing a solid fuel or a raw material for terephthalic acid production. This approach offers an innovative and sustainable solution to manage the waste generated by the increased use of disposable face masks during the pandemic. [ABSTRACT FROM AUTHOR]

Integrated gasification combined-cycle (IGCC) units, which use solid fuels (coal, petroleum coke, etc.) for combined-cycle power generation, have been under development for approximately half a century. At present, the countries of the Asian region show the greatest interest in this type of power plants. Two large IGCC power units entered into commercial operation at Nakoso and Hirono thermal power plants (TPPs) in Japan; in addition, the Osaki CoolGen project is advancing greatly. The People's Republic of China and the Republic of Korea are also improving their IGCC projects. Development of more efficient technologies for generator gas cleaning and application of the next generation of gas-turbine units (GTUs) at new IGCC units have cut down harmful emissions and increased the efficiency up to 48%. The 21st century has brought increased interest in IGCC units due to the ability of their equipment to capture CO2. Besides the above-mentioned advantages, IGCC units also have disadvantages, the biggest of which is their high cost. That is why, despite many IGCC projects to be deployed in the 2000s, most of these projects were subsequently canceled, and the plants built in the 1990s are being gradually decommissioned. The promising direction for future application of IGCC units is the production of hydrogen for fuel cells with simultaneous CO2 capture. The polygeneration technology already used at some facilities, which enable the generation and delivery to the consumer of not only electricity but also gasification by-products, will also render support to the solution of the economic problems of IGCC units. [ABSTRACT FROM AUTHOR]

Backgrounds: Household solid fuel have been associated with changes of handgrip strength, and exposure to ambient air pollution might be one risk factor of sarcopenia. However, the prospective association between household solid fuel use and sarcopenia remains limited. Methods: A total of 11,924 participants (5,723 men (48%) and 6,201 women (52%) with the average age was 59.17 ± 9.57 years) from the China Health and Retirement Longitudinal Study 2011 were included in cross-sectional analyses. 7,507 participants at baseline were included in longitudinal analyses and were followed up in 2015. Sarcopenia status was defined according to the Asian Working Group for Sarcopenia 2019 (AWGS 2019) criteria. Results: In cross-sectional analyses, the participants who used solid fuel for cooking and heating had higher prevalence of sarcopenia than those who used clean fuel. During the follow-up, 302 (4.02%) participants experienced sarcopenia. In the longitudinal analysis, after multivariable adjustment of age, sex and other risk factors, individuals who used solid fuel for cooking had an elevated risk of new-onset sarcopenia, with corresponding odds ratio of 1.32 (95% confidence interval, 1.03–1.71). Consistently, individuals reported solid fuels use for heating were associated with 20% (odds ratio=1.20, 95% confidence interval: 1.01–1.56) increased risk of sarcopenia. In addition, a self-reported switch from clean to solid fuel for cooking appeared to have an increased sarcopenia risk (odds ratio=1.20, 95% confidence interval: 1.02–1.43). Conclusion: Using household solid fuel for cooking and heating was associated with increased risk of sarcopenia prevalence and incidence. [ABSTRACT FROM AUTHOR]

In this study, the chars were derived through dry and wet torrefaction (DT and WT) of oil palm leaf (OPL), and techno-economic feasibility for char production was evaluated. DT was performed at 200 to 300 °C for 30 min under CO2 atmosphere. WT was performed at 180 to 220 °C for 30 min over process water (PW) reuse. Fuel properties of the DT-char and WT-char products, including mass yield, physiochemical characteristics, fuel properties, thermal stability, surface chemical functional groups, and surface structure were investigated. The study results indicated that DT affected OPL characteristics rather than WT, where the char with outstanding fuel properties was derived through DT. WT affected the fuel properties of OPL marginally. OPL chars with the highest HHV (28.67 MJ/kg), HHV improvement (0.48) and energy yield (131.78 %) could be derived via the DT. The O/C and H/C ratios of the DT-char were reduced and similar to those of lignite coal. PW reuse in WT slightly affected the char fuel properties, thus it is the outstanding method of PW utilization. Techno-economic feasibility analysis results determined that DT is the profitable process for converting OPL to char fuel, and its simple payback period is 14.13 years. These results recommended that DT constitutes a dominant technology for producing char fuel from OPL.

The relevance of the study is caused by the need to find technologies that can improve the environmental friendliness of the use of organic fuels in the process of energy supply. The main aim is research of microwave pyrolysis of solid organic fuels with different degrees of metamorphic transformation. Objects: solid organic fuels with varying degrees of metamorphic transformation, namely, wood waste (pine sawdust), lowland peat (Sukhovskoe deposit, Tomsk region), brown coal (Talovskoe deposit, Tomsk region), hard coal (grade D, Kuznetsk basin, Kuzbass). Methods. The characteristics of the initial fuel were determined according to generally accepted methods: humidity – SS R 52917-2008, volatile matter yield – according to SS R 55660-2013. The ash content of sawdust was determined according to SS R 56881-2016, peat – SS 11306-2013, coal – SS R 55661-2013. The fundamental difference between the standards used in terms of determining the ash content lies in the prescribed parameters of the analysis procedure (temperature, speed, time). The heat of combustion was determined using an ABK-1V calorimeter (RET, Russia) in accordance with SS 147-2013. The elemental composition of the feedstock and the solid carbon residue after its processing (C, H, N, S) was determined using a Vario Micro Cube analyzer (Elementar, Germany), using a standard sample (Sulfanilamide) as a verification. Research of the processing of the concerned fuels by the method of traditional slow-bed pyrolysis was carried out by the method of synchronous thermogravimetric analysis and differential scanning calorimetry using an STA 449 F3 Jupiter instrument (Netzsch, Germany). Microwave pyrolysis was implemented on a specially designed experimental stand (magnetron power 750 W, carrier frequency 2,45 GHz). The pyrolysis gas composition (the content of components such as H2, CH4, CO, СО2) was recorded in real time using a Test-1 gas analyzer (Boner, Russia). Results. By the method of differential thermal analysis, it was established that the temperature of the end of thermal transformation for biomass (sawdust and peat) is 600–650 °C, for brown coal – 850 °C, for hard coal – 900 °C. Comparing the results of slow-bed and microwave pyrolysis, it was noted that during microwave pyrolysis of fuel, 9,5–11,7 % less solid carbon residue is formed, and the yield of volatile (liquid and gaseous products) increases. At the same time, the pyrolysis gas generated in the process of microwave pyrolysis almost does not contain ballast CO2 in its composition, which, together with the low yield of carbonaceous residue, indicates a higher efficiency of thermal fuel processing compared to slow-bed pyrolysis. It is noted that with an increase in the degree of fuel metamorphism in the process of microwave pyrolysis, the share of generated synthesis gas (Н2+СО) in relation to the amount of methane obtained decreases, which is associated with the composition of the initial processed raw material: change of (СО+Н2)/СН4 in the pyrolysis gas correlates with the change of (Н+О)/С in initial fuels.

The article presents the results of laboratory combustion tests of the microbriquette obtained from useless coal (grain class of < 5 mm) generated in the production of “eco-pea” (eko-groszek) coal. The briquettes of 1.5 and 2.5 cm3 were made in a roller press of crushed coal granulation down to 2 mm, mixed with a binder and/or catalytic additives and sorbents, then dried to final moisture of about 7%. The tests were carried out on a specially designed stand enabling to determine the differential curve of the weight loss of samples heated to the ignition temperature and then burnt with laminar airflow by natural chimney draft. Comparative tests were carried out with ecopea coal from the “ZG Sobieski” mine. The results indicate that composite fuels, in the form of microbriquette, ignite faster, burn at a higher temperature and leave less ash when burned than lump coal. The greater reactivity of the briquette concerning the lump coal allows for minimizing the air rate by about 10%, which also reduces the exhaust gas volume by the same amount and the stack losses. It reduces the velocity of dust lifting, which leads to the reduction of their emission.

• Leather shavings do not allow for autothermal combustion when combusted directly. • Adding wood biomass to tannery waste results in a complete combustion of such mixture. • Lower quality pellets combustion results in a prominent afterburn. • Large percentage of additive leads to ash sintering, smaller additions result in fine ash. • The ash from wet blue tannery waste combustion traps large amounts of Cr 2 O 3. Leather processing companies are struggling with the problem of increasing costs of post-production waste disposal. Therefore, the issue of thermal waste disposal at the plant and the use of generated heat in the production process is becoming more and more popular. Leather waste on its own does not allow for autothermal combustion despite the sufficient higher heating value (HHV). Therefore the Authors proposed to improve the flammability of the fuel by adding a small amount of wood sawdust to leather waste and produce premixed pellets. Six such samples were incinerated in a laboratory-scale reactor, which enables the simultaneous measurement of characteristic temperatures, exhaust gas analysis and sample mass loss rate. Research has shown that even a small addition of sawdust enables a stable combustion process and does not cause the formation of sinters. In addition, studies of the ash showed that in the case of chromium-containing waste, a large part of it remained in the ash in the form of Cr 2 O 3. Nevertheless, very fine ash causes the small fraction chromium to be carried with the flue gas stream, therefore controlled agglomeration of the ash structure would be advisable in the final installation. Emission analysis showed high and moderately high NO x and SO 2 emissions, decreasing with the increase in the amount of sawdust addition in the sample. Research has shown that leather waste is not a burden, but can be an attractive and safe source of energy for the company, while improving waste management in a circular economy. [ABSTRACT FROM AUTHOR]

Energy and environmental issues have triggered the search for new sources of green energy alternatives in recent years. Biofuel production from renewable sources is widely considered one of the most sustainable alternatives for environmental and economic sustainability. Microalgae are currently being promoted as one of the most promising liquid biofuel feedstocks due to their rapid growth, high lipid production capacity, and carbon–neutral cycle. In this study, whole microalgae cells were utilized as raw material to produce solid biofuel, i.e., Bio-Coke, and this study aimed to investigate the possibility of microalgae Bio-Coke as an alternative to coal coke. The results show that Bio-Coke can be produced from microalgae in the temperature range of 80–100 °C. The apparent density is between 1.253 and 1.261 g/cm3, comparable to the apparent density of lignocellulosic Bio-Coke. Additionally, the calorific value is higher than the calorific value of lignocellulosic Bio-Coke and within the range of the calorific value of subbituminous coal. Therefore, microalgae Bio-Coke can be utilized to replace coal coke usage in the future. [ABSTRACT FROM AUTHOR]

Biomass pellets are one of the most crucial feedstocks for bioenergy production on a global scale due to their numerous advantages over raw biomass resources. Pellets provide improved energy density, bulk density, moisture content, and homogeneity thereby reducing storage, handling, and transportation costs. To produce high-quality solid fuel, it is necessary to comprehend the properties of wood fuel. This study explored the potential of Khaya senegalensis (khaya) as a dedicated energy crop (DEC) for the production of green energy. It thrives in less-than-ideal conditions and grows rapidly. The low durability of energy pellets raises the risk of dust and fire during handling and storage. In addition, the potential for fines and dust formation is strongly correlated with the mechanical strength of materials. Due to this necessity, the current study examines the effects of pelletization factors, including temperature and pressure, on pellet properties, particularly on its mechanical properties. The durability and compressive strength of pellets were determined using a sieve shaker and a universal testing machine, respectively. The highest mechanical durability was observed at 3 tons of pressure and 75 degrees Celsius, each with a value of 99.6%. The maximum axial compressive strength was measured at 57.53 MPa under 5 tons of pressure. When pelletized at 125 °C, the axial compressive strength increased by 13.8037% to 66.06 MPa compared to the strength obtained at 5 tons of pressure. Pelletizing Khaya feedstocks at 4 tons of pressure, on the other hand, produced a slightly lower diametral compressive strength of 7.08 MPa compared to 7.59 MPa at 125 °C. The experimental results revealed that the aforementioned factors significantly affect the mechanical properties of pellets. The elucidation of wood biomass, solid fuel qualities and pelletization parameters of this potential energy crop may facilitate the production of high-quality pellets from Khaya senegalensis wood to meet the increasing local and worldwide energy demands. [ABSTRACT FROM AUTHOR]

Hybrid rockets have distinct advantages over their pure solid or liquid propellant counterparts, and their performance can be improved by inclusion of metal additives. Several metallic additives (micro-Al, micro-Ti, micro-Mg, micro-Zr, nano-Al, nano-B, and Mg-coated nano-B) were selected as potential candidates for hybrid rocket applications and characterized by applicable microscopy techniques. The regression rates and combustion efficiencies of plain HTPB and HTPB loaded with each additive at various concentrations (10%, 20%, and 30% by mass) burning in GOX were evaluated at moderate oxidizer mass fluxes (10–150 kg/m2-s) and pressures ( ≤ 0.86 MPa, 125 psia). In general, the inclusion of any of the metallic additives led to a reduction in the regression rate and did not significantly change the combustion efficiency. The only exceptions were fuel formulations containing micro-Zr, which yielded a moderate (10–20%) increase in the regression rate at a concentration of 10%. The observed trends were more prevalent at higher oxidizer mass fluxes and higher additive loadings. The reductions in regression rate were attributed to heat transfer blocking effects derived from accumulation of additive particles on the fuel surface layer. These phenomena were especially prevalent in highly loaded fuel formulations containing the nano-additives that exhibited unstable combustion and periodic surface-layer shedding. Zirconium appears to be the best metallic additive available since it can yield the highest theoretical density-specific impulse under the lowest O/F operation ratio without resulting in decrements to overall performance. Notably, combustion efficiency data for all fuel formulations were well correlated to the combustion residence time, and high combustion efficiencies (>95%) were achievable when a satisfactory residence time (~75 ms) was realized. [ABSTRACT FROM AUTHOR]

The solid-fuel rotating detonation engine with gas generator is experimentally studied in this paper. This study solved the problems of ignition and stable detonation of pre-combustion gasification injection. The feasibility of solid pre-combustion rotating detonation is verified. A set of gas generators was designed and ignition tests were carried out. The detonation wave velocity is about 2625 m/s in the stable stage, which is about 20% higher than that generated by hydrogen/oxygen detonation. A maximum thrust of 69 N is obtained. Stable detonation pressure signal was obtained in our experiments. It is found that the detonation wave has experienced four stages in the formation process: deflagration, deflagration to detonation transition (DDT) process, galloping detonation, and stable detonation. In the stable detonation stage, coexistence of detonation waves with different strength is identified by high-speed photography images. • The feasibility of solid pre-combustion rotating detonation is verified. • The detonation wave velocity measured in the experiment is 2625 m/s. • The maximum thrust measured in the experiment is 69 N. • The detonation wave has experienced four stages in the formation process. [ABSTRACT FROM AUTHOR]

The article describes the results of experimental studies on the production of alternative solid fuels from coffee production waste -- coffee production waste and barley bran. Briquetted samples of solid fuels with 0 : 100, 25 : 75, 50 : 50 and 75 : 25 % wt. of coffee production waste and barley bran, respectively, were made. The influence of the content of the initial components on the main parameters of the created solid fuel briquettes was researched. It was determined that the higher calorific value of the obtained samples is in the range of ~17329 / 22147 kJ/kg, and their ash content is 0.6 / 2.45 % by weight. It is shown that with an increase in the content of coffee production waste in solid fuel samples, the calorific value increases and at the same time the ash content of the samples decreases. The creation of composite solid fuel briquettes makes it possible to use coffee production waste more rationally and regulate the main indicators of solid fuel to meet existing standards by means of the content of the components of the initial mixture. [ABSTRACT FROM AUTHOR]

Evidence on the potential risk factors of normocytic anemia, the most prevalent morphology subtype of anemia, was scarce to date. The purpose of this study is to investigate the association of cooking fuel use or daily cooking duration with normocytic anemia and further explore the modification effect of mechanical ventilation. Participants totaling 29,448 from the Henan Rural Cohort were included in this study. Normocytic anemia was defined by hemoglobin (based on the World Health Organization criteria) and mean corpuscular volume. Cooking-related data was collected by questionnaire, and the average daily cooking duration was calculated by the weekly cooking frequency and the cooking duration of each meal. Logistic regression models were employed to derive the combined and independent associations of cooking fuel type and daily cooking duration with normocytic anemia and the modification effect of ventilation. Compared with people who never cooked, both clean fuel and solid fuel users were significantly associated with increased prevalent normocytic anemia [OR (95% CI) = 1.196 (1.014, 1.411) and 1.335 (1.105, 1.614), respectively], and the effect estimates on normocytic anemia risk were 1.260 (1.043, 1.523), 1.320 (1.104, 1.578), and 1.310 (1.081, 1.587) in participants who daily cooked < 1 h/day, 1–2 h/day, and ≥ 2 h/day, respectively. These relationships were attenuated in subjects with mechanical ventilation (All P < 0.05). Cooking with solid fuel or for a long duration are independently associated with prevalent normocytic anemia in rural population, and mechanical ventilation could attenuate these associations. Future efforts to reduce the burden of anemia could target the universal use of ventilation and solid fuel use or cooking duration reduction. Clinical trial registration: The Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). Date of registration: 06 July, 2015. http://www.chictr.org.cn/showproj.aspx?proj=11375 [ABSTRACT FROM AUTHOR]

Hydrothermal carbonization (HTC) is a thermochemical process that utilizes biomass as feedstocks to produce hydrochars as solid fuel. Cotton textile wastes (CTW) are abundant; most are landfilled or incinerated, causing environmental pollution. CTW is rich in cellulose, thus suitable as biomass feedstock. HTC at a moderate temperature below 230 °C yields low-value hydrochars with low carbon content; however, an acid catalyst enhances the reaction. In this study, zinc-activated cotton textile waste (Zn-CTW) was synthesized via incipient wetness impregnation and used as a catalyst in hydrothermal carbonization to produce hydrochars. The reactions were conducted in a batch reactor at a temperature of 200 °C for 3 h. The effects of ZnCl2 catalyst loading on CTW were studied. The characteristics of hydrochars in terms of surface morphologies, hydrogen/carbon (H/C) and oxygen/carbon (O/C) ratios and surface functional groups were affected by the ZnCl2 loading on CTW. The results show that the hydrothermal carbonization of Zn-CTW-1.5 obtained hydrochars with the lowest H/C and O/C ratio values of 1.286 and 0.614, respectively. The FTIR analysis indicates stretching vibration of the C-O bond, which are the carboxylic acids and esters formed in the hydrochars. The hydrochars' surface morphologies show irregular and rough surfaces. It is concluded that Zn-CTW has the potential as a heterogeneous catalyst to produce hydrochars via hydrothermal carbonization. [ABSTRACT FROM AUTHOR]

Pellets have become an important renewable energy source. Aiming to contribute for diversifying the Brazilian energy matrix, the goals of this work were to evaluate the quality of the pellets of lignocellulosic residues (Eucalyptus and corn) produced with the addition of different percentages of Kraft lignin. For the production of pellets, mixtures of wood with bark of a Eucalyptusurophylla and Eucalyptusgrandis, and corn residue were used as raw material. The proportions of corn residue in the mixture were 0, 20, 25, and 30% (w/w). Except for the control (0% lignin), 2 and 5% (w/w) Kraft lignin were added to a dry mass of raw material in the 4 different mixtures. Pellets were produced in a laboratory press pelletizer with horizontal circular array. The following properties of the pellets were evaluated: proximate analysis, high heating value (HHV), elementary analysis, energy density, bulk density, diameter and length, hardness, mechanical durability, and fine content. The pellets were classified according to European marketing standards. The addition of Kraft lignin to eucalyptus and corn residue pellets contributed to improving the physical and mechanical pellet properties, as regards the bulk density, mechanical durability, and fine content, allowing the transportation of a greater amount of mass and energy, besides maintaining the integrity of the biofuels during handling and use. The mixing of eucalyptus with corn residue is an effective way to optimize properties of biomass solid fuel. The treatment with higher corn addition, in relation mechanical properties, showed a better performance in accordance with the European standards. The mechanical properties were above to 97.5%, besides that has no impact from the addition of Kraft lignin. The addition of up to 20% of corn residue has the potential to improve physical and mechanical pellet quality, with or without Kraft lignin addition. Thus, similar amounts to that of the treatment with the proportion of 80% eucalyptus and 20% corn residue can be a viable alternative to the production of pellets. [ABSTRACT FROM AUTHOR]

The addition of finely divided solid fuel to bauxite charge has been proposed as a strategy for improving the technical and economic parameters of the process of sintering bauxite charge in a rotary furnace. The additive, which marginally deteriorates the quality of the initial components, contributes to the development of internal crystallochemical transformations in the resulting sintered mass owing to a change in the intensity of heat and mass transfer processes. Laboratory studies of thermal transformations in the bauxite charge sinter have shown that the development of the transformations reduces the temperature differences across the sample cross section. Increasing the addition of solid fuel contributes to the shifting of the compaction processes of the sintered mass to the area of elevated heat treatment temperatures. The intensification of the conditions for the development of internal crystallochemical transformations using an internal heat source in the form of a solid fuel additive up to 1% increases the amounts of aluminum and sodium oxides in the solution after the leaching of the resulting sinter. [ABSTRACT FROM AUTHOR]

Aim: Over half the world's population, mostly from developing countries, use solid fuel for domestic purposes and are exposed to very high concentrations of harmful air pollutants with potential health effects. The effect of indoor air pollution becomes much more severe for older adults because of their weakened immune system with multiple health risk factors. Compared with ambient air pollution, little is known about cognitive health in relation to indoor air pollution. Therefore, this study explores the association between indoor air pollution due to solid fuel use and cognitive function of older adults in India. Subject and methods: The study used data from wave 1 of the WHO Study on global AGEing and adult health (SAGE). Bivariate analysis and a two-stage multilevel linear regression model were applied. Results: Our findings indicated that indoor air pollution is strongly associated with cognitive function. Results show lower cognitive function scores among older adults in households using solid fuel, women with lower or no education, and belonging to the disadvantaged section of the society. Older adults from poor socioeconomic backgrounds were more exposed to indoor air pollution compared to their counterparts, which indirectly increases the risk of poor cognitive function. Conclusion: Indoor air pollution from solid fuel use may be a salient factor for the cognitive health of older adults in India. A large proportion of India's population relies on solid fuel pointing to the need for urgent intervention programmes to reduce the usage of solid fuel in the country. [ABSTRACT FROM AUTHOR]

Consumption of solid fuels (such as biomass, dung, and coal) causes household air pollution, which reportedly is responsible for over 3.5 million premature deaths worldwide. Therefore, over the last couple of years, national governments, and organization as well as international organizations are promoting energy transition from these solid fuels to clean and modern fuels in households. This paper aims to provide comprehensive review of the conceptualization and the drivers of the household energy transition to clean fuels. A systematic literature review approach was identified and used to systematically identify, select, evaluate, and synthesize the relevant published and gray literature appropriate to answer the research question of the study. It is found that the majority (78.4%) of studies conceptualized household energy transition as a switch/shift from one energy fuel to another, while few studies conceptualized energy transition as a change in energy conversion technologies (11.8%) and change in energy use patterns (9.8%). Furthermore, this study found that majority of the studies identified socioeconomic and market/economic factors as key determinants of household energy transition with few studies reported environmental factors, behavioral and government/structural factors as drivers for household energy transition.

Abstracts: Background: Few studies examined the associations of household fuel combustion with incident diabetes. The current study emphasizes the association of domestic fuel combustion with diabetes among middle- and older- Chinese. Methods: The data was extracted from a national and prospective cohort, the China Health and Retirement Longitudinal Study (CHARLS), which enrolled adults ≥ 45 years. A total of 4610 and 5570 participants were involved in heating and cooking-related analyses. Multivariable logistic models were conducted to assess the association of domestic fuel combustion for heating and cooking with diabetes. Furthermore, we also examined whether it differed from switching fuel types. Subgroup and interaction analyses were performed based on covariates to examine the robustness and find potential effect modifiers. Results: After about 5-year follow-up, 592 and 716 diabetes were diagnosed in heating and cooking-related analyses. Compared to cleaner fuel users, those who used solid fuel for heating [OR (95 % CI):1.32 (1.05–1.66)] maintained higher risks of incident diabetes. In addition, participants who were exposed to solid fuel for both heating and cooking [OR (95 % CI):1.55 (1.17–2.06)] might have further elevated diabetic risk. Those risks are likely to be attenuated if people switched cooking fuel from solid to cleaner [OR (95 % CI): 0.68 (0.53–0.89)]. Conclusions: Home solid fuel use for heating is associated with an increased risk of incident diabetes. If solid fuel was concurrently used for both cooking and heating, those risks might be further elevated. Interestingly, as compared to solid fuel users, the participants switching cooking fuel types from solid to cleaner presented reduced diabetic risk.

Abstract With an increasing prevalence of hypertension, indoor air‐pollution factors began to attract extensive attention. However, the association of cooking fuel with the incidence of hypertension was inconsistent. The aim of this study was to investigate the association of household air‐pollution caused by cooking fuel with the incidence of hypertension. Data were derived from the China Health and Nutrition Survey. Participants aged 18 years or older were eligible. A validated questionnaire was used to collect the information on the type of cooking fuel, including electricity, natural gas, coal, and wood/charcoal. Participants with a systemic blood pressure (SBP) ≥ 140 mmHg or /and a diastolic blood pressure (DBP) ≥ 90 mmHg without use of anti‐hypertensive medications, or participants with an SBP/DBP

The paper presents the technology of multi-component briquetting of solid fuel (MSF-fuel) developed by the authors, which makes it possible to reduce economic losses from the non-use of combustible waste from industrial and municipal human activities. The issues of energy and resource saving, rational use of natural and secondary resources in accordance with the National Strategy for Sustainable Development of the Republic for the period up to 2035 are considered in the paper. The concept, structure and principles of the circular economy are analyzed. The paper provides characteristics of the main areas of use and processing of waste that have not found application in traditional technologies and energy. Some aspects of the conducted research on the production of multicomponent solid fuels are presented in the paper. The technology of briquetting wet mixtures with the addition of various binders, including combustible waste, is described, taking into ac-count the factors that affect the performance of the briquetting plant and the density of the fuel. Various ratios of the components of briquetting fuel have been analyzed and the compositions are determined, at which the best production, consumer and environmental indicators are analyzed. The paper studies the energy and physicochemical characteristics of the produced multicomponent fuel. Algorithms for selecting fuel components have been developed. The results obtained can be used to solve problems of rational use of combustible industrial waste by producing a multicomponent solid fuel that meets the established energy and environmental requirements.

IntroductionBiomass fuel remains the most common type of fuel used in many developing countries, leading to indoor air pollution and serious health impacts.ObjectiveThe objective of this study was to compile evidence on the impact household fuel combustion has on child and adult health, with an emphasis on solid fuel use in Gaza.MethodsIn this cross-sectional study, 110 structured self-administered questionnaires were distributed in April 2019 among families living in the Al-Maghazi refugee camp.ResultsParticipants reported that the main fuel used were wood, coal, cardboard, and a mix of wood, cardboard, and plastic, which were used for cooking, heating, baking, boiling water, and lighting. The most common symptoms were nasal irritation (71.8%), followed by headache (66.4%) and dizziness (65.4%). The results of logistic regression showed that the participants who used wood fuel had a higher chance of feeling eye irritation than those who used a mix of wood, cardboard, and dried grass (OR = 1.316; 95% CI = 1.54–8.99). The participants who opened windows during the burning process of biomass fuel were five times more likely to develop pneumonia than those who closed windows (OR = 5.53; 95%CI = 11.60–19.0).Conclusionthere is an urgent need for community awareness campaigns designed to inform people about the risks of exposure to biomass fuel smoke and how to better implement household ventilation.

Background: Household solid-fuel burning contributes to indoor air pollution and is linked to poor cognitive function, but how solid cooking fuel use leads to cognitive decline over time is not well elaborated. Objective: We examine the associations of solid cooking fuel with cognitive function among three nationally representative cohorts. Methods: This study uses data from the 2010–2018 China Family Panel Studies (CFPS), the 2011–2018 China Health and Retirement Longitudinal Study (CHARLS) and the 2003–2015 Mexican Health and Aging Study (MHAS) in adults over the age of 50. Time varying Cox model was conducted to measure the association between cooking fuel types and cognitive decline. Mediation analysis was used to estimate the potential mediation effects on the associations of cooking fuel types with cognitive decline risk. Results: Respondents in CFPS, CHARLS, and MHAS relied on solid cooking fuel at baseline approximately 56 %, 51 %, and 12 %, respectively. Using solid fuel was consistently associated with higher risk of cognitive decline in three cohorts (CFPS: HR = 1.300 [95 % CI: 1.201, 1.407], CHARLS: HR = 1.179 [95 % CI: 1.059, 1.312], MHAS: HR = 1.237 [95 % CI: 1.123, 1.362]). Compared to those with persistent solid fuel, persistent clean fuel and change from solid fuel to clean fuel were associated with a lower risk of cognitive decline. Hypertension, diabetes, physical activity, dyslipidemia and high-density lipoprotein cholesterol (HDL-C) may partially mediate the cognitive decline caused by solid fuel use. Of the cognitive decline burden, 18.23 % (95 % CI: 12.21 %, 24.73 %) in CFPS, 8.90 % (95 % CI: 2.93 %, 15.52 %) in CHARLS and 2.92 % (95 % CI: 1.52 %, 4.46 %) in MHAS of cognitive decline cases attributable to solid cooking fuel use. Conclusion: The use of solid cooking fuel is associated with a higher risk of cognitive decline. It is essential to promote the expanded use of clean fuel to protect cognitive health.

Multi-crop plants (fibrous hemp, maize, and faba bean) can potentially be an alternative to wood biomass pellets, but there is no detailed knowledge to support the suitability of this biomass for solid biofuel production. The aim of this study is to analyze and justify the suitability of multi-crop plant biomass for the production of biofuel pellets and to assess the environmental impact of burning them. This paper presents studies of physical-mechanical, thermal, and chemical characteristics of biofuel pellets from multi-crop plants and emissions during their combustion under laboratory conditions. The main parameters of the produced pellets were determined according to international standards, which are detailed in the methodology part. The length of the produced pellets ranged from 17.6 to 26.6 mm, and the diameter was about 6 mm. The density of wet pellets varied from 1077.67 to 1249.78 kg m−3. The amount of ash in the pellets varied from 5.75% to 8.02%. Determined lower calorific value of all pellets was close to 17.1 MJ kg−1. The lowest CO and CxHy emissions were determined when burning MIX2-1 pellets (biomass of the binary crop); their values were 572 and 29 ppm, respectively. The lowest content of CO2 was determined when burning S-Mz pellets (mono crop biomass), and it was 3.5%. The lowest NOx emissions were also determined when burning the pellets of this sample, with a value of 124 ppm. Research results show that multi-crop plants are a suitable raw material for the production of solid biofuel, the burning of which does not cause negative consequences for the environment. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass from rice husk (RH) is a renewable resource for fuel production, but it could pose ash-related challenges. This work focused on investigating the effects of pretreatment at different sodium hydroxide (NaOH) concentrations (i.e., 0.0, 0.25, 0.50, 0.75 and 1.00 M) on the calorific values and ash contents of treated RH products, and also finding the optimal torrefaction conditions. The results showed that alkaline pretreatment by sodium hydroxide (NaOH) reduced the ash content in the RH samples by over 85 wt%. Due to its relatively excellent calorific values and low ash content, the RH sample with 0.25 M NaOH pretreatment (i.e., RH-25) was chosen as a starting feedstock in the subsequent torrefaction experiments as a function of 240–360 °C for holding time of 0–90 min. In addition, the surface properties by scanning electron microscopy—energy dispersive X-ray spectroscopy (SEM-EDS) and Fourier-transform infrared spectroscopy (FTIR) were also used to observe the elemental compositions preliminarily. Based on the fuel properties of the torrefied RH products, the optimal torrefaction conditions can be found at around 280 °C for holding 30 min. As compared to the calorific value of the RH-25 (i.e., 18.74 MJ/kg) and its mass yield (i.e., 0.588), the calorific value, enhancement factor and energy yield of the optimal product were 28.97 MJ/kg, 1.55 and 0.91, respectively. Although the resulting product has a high calorific value like coal, it could have slight potential for slagging and fouling tendency and particulate matter emissions due to the relatively high contents of silicon (Si) and sodium (Na), based on the results of EDS and FTIR. [ABSTRACT FROM AUTHOR]

This paper presents the modeling and simulation of an industrial-scale chemical looping combustion (CLC) power plant, including all process units (reactors, flue gas treatment units, heat integration, steam cycle, and CO2 compression train). A model of a 525 MWth CLC power plant was built using a rigorous representation of the solid fuel and oxygen carrier. Petcoke was considered the main fuel of interest in this study, and it is compared with other solid fuels. The flue gas compositions obtained with the model show that cleanup units are mandatory to comply with CO2 quality requirements. High levels of flue gas treatment, including 97.1% deNOx and 99.4% deSOx, are needed to achieve typical specifications for captured CO2. This is mainly due to the high level of contaminants in the fuel, but also to the absence of nitrogen in the CLC flue gas, thus resulting in higher concentrations for all substances. The high level of flue gas treatment is thus one of the important challenges for solid fuel combustion in CLC. The overall CO2 capture efficiency of the plant is estimated to be as high as 94%. Regarding the energy balance, a process net efficiency of 38% is obtained. Comparing the results with other available technologies shows that CLC exhibits one of the highest net plant efficiencies and carbon capture rates. CLC is thus a promising technology to produce clean energy from solid fuels. Finally, based on a sensitivity analysis, it is shown that process efficiency is mainly affected by the design and performance of the CLC furnace, the steam injection rate in the fuel reactor, the char separation efficiency, and the excess oxygen in the air reactor. [ABSTRACT FROM AUTHOR]