Coal Briquettes Research Articles

Effect of coal type on aerosol optical properties at Ulaanbaatar city

In this study, seasonal characteristics of aerosol optical properties at Ulaanbaatar station of the international network of SKYNET are investigated using ground-based skyradiometer from the years extending from 2017 to 2023. The aerosol optical thickness (AOT) at 500nm wavelength and Angstrom exponent (AE) were determined in winter to evaluate the decrease in air pollution in Ulaanbaatar since implementing the government's decision to use coal briquettes for household heating. During the study period, the monthly mean AOT at 500nm varied throughout the year, with the maximum value of 0.178±0.004 obtained in winter due to households burning large amounts of biomass, and the highest AOT (0.183) was obtained in February. The mean AOT was 0.21 in the winter of 2017-2019, which decreased by 15 per cent to 0.18 in the winter of 2019-2023.

Effects of outdoor air pollution on hospital admissions from cardiovascular diseases in the capital city of Mongolia

Cardiovascular diseases (CVD) are one of the primary causes of morbidity worldwide, while ambient air pollution (AAP) is a major contributor to CVD. This study is the first study that aimed to compare the differences in AAP concentrations and acute effects on the risk of admissions from CVD, ischaemic heart diseases (IHD), and stroke before and after introducing the new type of coal briquette in Ulaanbaatar, Mongolia. We collected daily hospital admission records, air quality and meteorology data between January 1, 2016 and December 31, 2022. The relative risks (RRs) of cause-specific hospitalisations associated with daily concentrations of AAP were estimated by a time-stratified case-crossover analysis with conditional Poisson distributed lag models. Overall, acute exposure to the pollutants, except for O3, was positively associated with an increased risk of all admissions. For each interquartile range (IQR) increase in PM2.5, PM10, SO2, NO2 and CO, the risk of CVD admissions increased by 0.5% (RR=1.005; 95% CI: 0.998, 1.012) at lag0, 2.9% (RR=1.029; 95% CI: 1.014, 1.044), 2.5% (RR=1.025; 95% CI: 1.010, 1.040), 4.1% (RR=1.041; 95% CI: 1.016, 1.068) and 0.3% (RR=1.003; 95% CI: 0.995, 1.012) at lag01, respectively. Subgroup analyses showed greater risks of CVD admissions for women and people aged <65 years, in the cold season, and after the raw coal ban period. During the cold winter season, Ulaanbaatar’s AAP levels remained higher than the World Health Organization’s guidelines, regardless of consuming the new coal briquettes. Adopting alternative efficient methods to improve air quality and associated health outcomes is necessary.

Effect of the Size of Coal Briquette on Its Internal Structure

Effect of the Size of Coal Briquette on Its Internal Structure

Properties of biocoal briquettes from mesoporous coals and rice husk and their effects on environmental pollution

This work assessed some properties and effects of biocoal briquettes on environmental pollution compared with utilising coal alone. A mixture of coal fines and rice husks was prepared, with cassava starch gel as a binder, before compaction in a briquetting machine and drying with a solar dryer. Samples of the coal fines, rice husk, cassava flour and briquettes were analysed for their elemental and oxide concentrations via an energy-dispersive X-ray fluorescence analyser. The heat fuels were analysed for their thermal behaviour via thermogravimetric analyser (TGA), whereas the specific surface area, pore size and pore volume were determined using a Brunner–Emmett–Teller (BET) analyser. The conversion of the tested coals to biocoal briquettes resulted in a reduction in the level of arsenic in the briquettes. Additionally, the sulphur level decreased from 1.96 to 1.11% in the Okobo-Enjema briquettes and from 1.78 to 0.90% in the Onyeama briquettes. However, the levels of manganese increased from 0.04 to 0.22% in the Okobo-Enjema briquettes and from 0.04 to 0.21% in the Onyeama briquettes. Thermogravimetric analysis at different heating rates revealed that derivative weight loss increased with increasing heating rate, from 4.4% at 10 °C/min to 5.5% at 20 °C/min. BET analysis revealed that the briquettes had larger pore diameters, volumes and specific surface areas than did the coal samples. The coal samples have greater propensity to pollute the environment as the amount of potentially hazardous elements in the samples is greater than in their biocoal briquettes.

A semi-industrial investigation about the use of iron-steel production by-products in reactive coke production

This study investigates the utilization of by-products from iron-steel integrated plants in the production of reactive coke. Various by-products were evaluated, and blast furnace flue dust with high iron (Fe) content was incorporated into the coal blend through the briquetting of highly volatile coal. The blend consisted of 10 % briquette coal comprise 1 % blast furnace flue dust. The addition of blast furnace flue dust with briquettes aimed to mitigate the reduction in coke strength caused by increased reactivity. Reactive coke was successfully produced through the evaluation of blast furnace flue dust, a by-product of iron and steel plants. The resulting reactive coke exhibited a reactivity value approximately 20 % higher than coke produced without the addition of blast furnace flue dust while maintaining its strength. By re-evaluating blast furnace flue dust as a by-product of the iron and steel process, the reactivity of coke increased without compromising its strength.

Insight into emission reduction effect of coal and biomass mixed briquette fuel

The use of coal and biomass as fuel is still the dominant method for domestic heating and cooking worldwide, particularly in rural areas, leading to degenerate atmospheric quality and human health. Briquette technology is regarded as an efficient way to suppress pollutant emissions from solid fuel combustion. In this study, a novel method for coal briquette (for both bituminous and anthracite) is presented in which biomass is added as an additive (0–30%) in producing clean coals. The comprehensive evaluations of these briquettes were done by measurements of the major pollutants, including particulate matter (PM), elemental and organic carbon (EC and OC), inorganic ions, volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs). Emission factors (EFs) for fine PM (PM2.5) and total carbon exhibited similar ranks between all coal groups, while the bituminous group yielded relatively higher EFs for the pollutants. The briquette technology showed a certain reduction effect in the bituminous group. The emission of coals, biomass, and their briquettes showed a substantial difference (>0.75) according to the coefficient of divergence. The EFs for total VOCs in bituminous, anthracite, and biomass groups ranged from 4.53 ± 0.45–23.4 ± 3.84, 0.68 ± 0.02–5.05 ± 0.02, and 140 ± 1.02 g/kg, respectively. An obvious watershed occurred in bituminous briquette with 15% biomass-added that increased emission beyond the additive amount, which highlighted the importance of mixing ratios for emission reduction. Compared to estimated emissions, the mix of biomass and coals through the combustion process released inorganic and organic species with different levels than the direct biomass and anthracite combustion emission, and around 15% is the suitable amount of biomass added to achieve the desired effect. The key findings of briquette technology provide an effective way for solid fuel combustion to alleviate the associated negative impacts and promotion value in developing regions, especially in rural areas.

Resolving emission factors and formation pathways of organic gaseous compounds from residential combustion of European brown coal

Residential combustion of brown coal can be an important source of ambient air pollution in areas with abundant brown coal deposits, such as Eastern Europe or China. The exhaust emission contents may vary regionally depending on the fuel composition, calling for detailed characterization of emissions from different coal types. In this work, the organic gaseous emissions of European brown coal combusted in a modern chimney stove -type residential appliance were measured by a proton transfer reaction time-of-flight mass spectrometer. Of three consecutive batches of brown coal briquettes, the first batch produced two-fold emission (144 ± 52 mg/MJ) of organic gaseous compounds (OGCs) compared to the later batches (71 ± 35 mg/MJ). The compositions between the batches were, however, relatively similar. Carbonyls accounted for 36 ± 3.0% of the identified emission factors, while aromatic hydrocarbons and oxygenated aromatic compounds contributed 19 ± 3.4% and 16 ± 1.8%, respectively. The complex and overlapping chemical processes within batch combustion were exposed by non-negative matrix factorization, giving insight into the temporal variation in the formation pathways of the OGCs. The OGCs were separated into five factors revealing the chemical fingerprints of the main processes leading to formation of, for example, substituted or single-ring aromatic hydrocarbons. Oxygenated aromatic compounds were related to a distinct factor, which was proposed to form specifically from decomposition of the lignin residues of the brown coal. OGCs from brown coal combustion were estimated to have notable secondary particle formation potential: in photochemical conditions, they may double the organic particulate emission, while reactions in dark conditions may lead to excessive nitrophenol formation.

Experimental study on the impact of “IDS + JFCS” complex wetting agent on the characteristics of coal bodies

As China's coal mines have transitioned to deep mining, the ground stress within the coal seams has progressively increased, resulting in reduced permeability and poor wetting ability of conventional wetting agents. Consequently, these agents have become inadequate in fulfilling the requirements for preventing washouts during deep mining operations. In response to the aforementioned challenges, a solution was proposed to address the issues by formulating a composite wetting agent. This composite wetting agent combines a conventional surfactant with a chelating agent called tetrasodium iminodisuccinate (IDS). By conducting a meticulous screening of surfactant monomer solutions, the ideal formulation for the composite wetting agent was determined by combining the monomer surfactant with IDS. Extensive testing, encompassing evaluations of the composite solution's apparent strain, contact angle measurements, and alterations in the oxygenated functional groups on the coal surface, led to the identification of the optimal composition. This composition consisted of IDS serving as the chelating agent and fatty alcohol polyoxyethylene ether (JFCS).Subsequent assessment of the physical and mechanical performance of the coal briquettes treated with the composite wetting agent revealed notable enhancements. These findings signify significant advancements in the field and hold promising implications. Following the application of the composite wetting agent, notable reductions were observed in the dry basis ash and dry basis full sulfur of coal. Additionally, the water content within the coal mass increased significantly, leading to a substantial enhancement in the wetting effect of the coal body. This enhanced wetting effect effectively mitigated the coal body’s inclination towards impact, thereby offering technical support for optimizing water injection into coal seams and preventing as well as treating impact ground pressure.

Necessary CO2 emissions improvement based on rural residential coal/stove-specific coal combustion and prefectural-differentiation synergistic effect of pollutants and carbon emission reduction

Rural residential coal combustion (RRCC) is an important CO2 emission source in rural areas and these emissions vary greatly by coal and stove types. The lack of CO2 emission estimations for different coal-stove combinations restricts refinement and region-differentiated synergistic reduction of pollution and CO2 emissions from RRCC. This study established the coal and stove specific CO2 emissions inventory of RRCC based on investigated coal combustion of various coal and stove types, taking the region of Hebei in China as an example. The synergistic reduction effect of CO2 and pollutants was evaluated using 4 emission reduction scenarios. CO2 emission was 67.4% higher than estimates of RRCC based on the Statistical Yearbook and IPCC emission factors. The combination of bituminous coal and an advanced coal stove was the greatest contributor (62.1%) to CO2 emissions. Bituminous coal burnt in home Arcola has the highest per capita hourly and per unit calorific value CO2 emission, 2.3 and 2.4 times higher than the combination of anthracite briquette coal and pit coal stove and the combination of bituminous coal and an advanced coal stove, respectively. Except for NOx and CO, the coal-stove combination with the lowest per capita hourly and per unit calorific value emissions is anthracite briquette coal and an advanced coal stove. Scenario analysis shows that updated coal stoves feature the highest pollutant emission reduction, but greater CO2 and NOX emissions. For individual cities, synergistic pollution and carbon reduction is seen in Tangshan and Qinhuangdao, and organic carbon, CO, and SO2 have better synergistic positive reduction with CO2, while NOX has shown a negative effect with CO2 in other cities with the best coal and stove update scenario. Compared with the coal and stove update scenario, emission reduction effects with clean fuel substitution varies across cities. This study is helpful to understand the possible non-synergy of pollutant and CO2 reduction in the process of RRCC management. Attention should be given to issues related to the synergistic control plan of pollution and CO2 reduction for RRCC with local adaptation.

Technology for Producing Heat From Composite Coal Fuels in Advanced Oven for Municipal and Household Use

The problem of rational use of coal remains relevant; currently, various technologies have been developed for producing composite solid fuels, briquettes with various binding materials from brown coal deposits in Kyrgyzstan. The widespread use of composite solid fuels (CSF) and coal briquettes in industry, everyday life and public utilities, in our opinion, is limited by two reasons: excessively inflated requirements of existing standards for the physical and mechanical characteristics of briquettes as a product; poor knowledge of optimal conditions for burning briquettes. Our research shows that compressive strength in the range of 15-20 kgf/cm2 provides the necessary strength for the degree of abrasion during transportation and storage of large-sized rectangular CSFs. Reducing the strength requirement to the value indicated above makes it possible to form briquettes from unsorted culm. Among the numerous known binders for briquetting, inorganic types of clays and loams, which are ubiquitous, deserve special attention. It has been established that clays and loams provide the strength of the CSF over 20 kgf/cm2. For the purpose of beneficial use of low-grade fine coal, we carried out briquetting and combustion testing of the resulting briquettes. It has been established that when briquetting coals from the Zhatan and Kumbel deposits with a clay binder, with an increase in the content of fine coals in the composition, the burning time of the briquette increases, as well as the combustion of the combustible mass increases, and the temperature in the combustion space increases. It has been shown that with the help of appropriate minor modifications of standard household stoves it is possible to significantly increase the combustion efficiency of all types of low-grade fuel, including lignite high-ash CSF.

Study of the process of obtaining fuel briquettes from production waste

Wastes from the coal industry, the oil and fat industry, and the processing of agricultural products can be turned into high-quality fuel raw materials. In this regard, research and development is underway in many countries, the results of which are new types of fuel. the results obtained, based on a scientifically based approach to the selection of effective compositions of organomineral components, made it possible to develop effective compositions of coal briquettes; Based on the research results, optimal compositions of effective coal briquettes based on organomineral ingredients from local raw materials and industrial wastes have been developed.

Refining of High-Carbon Steel and Reduction of CO&lt;sub&gt;2&lt;/sub&gt; Emissions by Using Lignite Upgraded Coal Briquettes

Refining of High-Carbon Steel and Reduction of CO&lt;sub&gt;2&lt;/sub&gt; Emissions by Using Lignite Upgraded Coal Briquettes

Emission characteristics of VOCs emitted from household stove combustion in the north of China

The emissions of volatile organic compounds (VOCs) arising from household stove combustion of different fuels common in North China were quantified. Using a dilution tunnel sampling system and gas chromatography-mass spectrometry analysis, 107 different C2–C12 VOCs were identified in flue gases of four household solid fuels (coal briquette, honeycomb briquette, wood, and cornstalk), whose emission factors were 670 ± 550, 1322 ± 686, 1200 ± 1923, 8670 ± 8380 mg kg−1, respectively. Alkenes and alkynes contributed the most to the VOC emitted from the combustion of honeycomb briquettes (50.1%), wood (46.3%), and cornstalks (56.9%). N-Alkanes were the dominant VOC (43.9%) from coal briquette combustion. Ethane and ethene were the most abundant individual species found in the flue gas of coal briquettes, wood, and cornstalks, accounting for 60.4%, 59.8%, and 67.9% of the emissions, respectively. The VOC emitted from coal briquettes, honeycomb briquettes, wood, and cornstalks exhibited significantly different chemical reactivities. The OH reactivity of the VOCs from cornstalk combustion was 9–270 times greater than that of the other fuels. The differences in the atmospheric reactivity of emissions would suggest that cornstalk combustion should be prioritised in any strategy to reduce ozone pollution.

Utilization of Biowaste for Sustainable Production of Coal Briquettes

In energy scarcity, particularly in Agri-based developing economies, bio-coal briquetting is the most suitable means of meeting sustainable energy needs utilizing agricultural waste. In this study, briquettes were made from an indigenously designed briquetting machine for investigating coal–biomass proportion blend using coal from Dara Adam Khel, Khyber Pakhtunkhwa in Pakistan, and pomegranate/olive waste to analyze their resulting calorific value, strength, and geochemical properties. A central composite design (CCD) and response surface methodology (RSM) were employed to design the experiments and analyze the data. Regression models were developed for each biomass type, demonstrating their adequacy and reliability for further analysis and prediction. Energy Dispersive X-ray Spectroscopy (EDX) analysis provided insights into the elemental composition of the coal briquettes. Mechanical analysis was performed to assess the strength of the briquettes, with varying compositions showing different levels of strength. Optimization using a composite desirability function yielded an optimal calorific value of 6728 kJ/kg. In summary, this study underscores the viability of bio-coal briquetting as a transformative solution to alleviate energy scarcity. Repurposing agricultural waste curtails resource depletion while mitigating waste disposal challenges. The optimized calorific value aligns with eco-friendly energy initiatives, advancing a greener path toward energy security.

Effects of PM2.5 emissions from household fuel combustion on biomarkers and pulmonary function in rural areas of Fenwei Plain, China

Rural household solid fuel combustion poses serious health risks in China. This study investigated the effects of PM2.5 and its organic carbon (OC) and elemental carbon (EC) emissions from various solid fuel combustion on biomarkers (i.e., interleukin-6 [IL-6], 8-hydrox-2′-deoxyguanosine [8-OHdG], and vascular endothelial growth factor [VEGF]) in human urine (u) and saliva (s) as well as on lung function. A total of 148 villagers burned various solid fuels (i.e., clean briquette coal, raw coal chunk, and biomass) in rural areas of Fenwei Plain in China were selected. The biomass group demonstrated the highest u-IL-6, s-IL-6, and s-8-OHdG levels, which were 1.2–3.1 times those of coal groups, whereas the clean briquette coal group exhibited the highest u-8-OHdG, and u-VEGF levels. In linear regression controlled for variables, a 1 g kg−1 increase in PM2.5 emission factor (EF) resulted in a decline in u-VEGF levels by 0.553 μg mol−1 UCr and increases in s-IL-6 and s-8-OHdG levels by 0.119 and 0.545 μg mol−1 UCr, respectively. A 1 g kg−1 increase in OC EF was associated with the upregulation of s-IL-6 and s-8-OHdG levels by 0.187 and 14.421 pg mL−1, respectively, a 1 g kg−1 increase in EC EF led to an increase in s-IL-6 by 0.354 pg mL−1. No significant differences in pulmonary function were observed among the three groups, nor did PM2.5 and its OC and EC significantly affect lung function. Through noninvasive tests, this study provided evidence on the effect of PM2.5 emitted from household fuel combustion emissions on human inflammation and oxidative stress responses.

Thermal extraction of coal and derivatives to prepare hot-pressed coal briquette for COREX application

In this study, the thermal extraction of various coal and derivatives by N-methylpyrrolidone was systematically compared and the extract was used as binder to prepare hot-pressed coal briquettes (HPCBs). The results demonstrate the effectiveness of thermal extraction in converting coal to HyperCoal, and the conversion yields varied from 12 to 71%. While the extraction tends to have a linear relationship with hydrogen-carbon ratio of raw coals, this relationship was not directly observed for derivatives due to inherent changes occurring during production. Proximate analysis of the extract reveals a reduction in ash content to below 1% while an increase in volatile matter by more than 8%. XPS and FTIR spectra demonstrate the high efficiency of thermal extraction in extracting hydrocarbons, but poor for compounds such as alcohols, phenols, ethers, and carboxylic acids. The extracts, rich in hydrocarbons, exhibited excellent thermoplasticity, making them suitable binders for HPCBs preparation. Among the extracts, coal derivatives exhibited higher compressive strength compared to coals. Consequently, the extract derived from direct coal liquefaction residue with the highest compressive strength was selected for preparing HPCB. Furthermore, we investigated the application characteristics of the HPCB and identified its great potential for use in COREX melting-reduction ironmaking. The preparation of HPCB is vital for expanding the utilization of bituminous coals while reducing dependence on lump coal and coking coal resources.

The Ger Plug-In: demonstrating a model for sustainable and affordable housing in Ulaanbaatar’s fringe districts

The article demonstrates that the Ger Plug-In, a housing prototype that combines the traditional Mongolian nomadic dwelling, or ger, with new construction, is a viable sustainable and affordable housing product that addresses urgent issues that have arisen from the growth of Ulaanbaatar’s ger districts. These settlements have no water supply, sewers or centralised heating, and households use coal and coke briquettes to heat their homes. The prototype provides the ger with electrical heating,, sanitation systems and improved thermal insulation. The pilot project was constructed in 2017 and on-site field measurements together with numerical simulation have been used to calculate its Energy Use Intensity (EUI). By using both quantitative and qualitative methods, the results show that the Ger Plug-In meets the EUI criteria to be eligible for green mortgages provided by the Green Climate Fund. Household surveys were conducted to ascertain the financial capacity of residents. By proving its qualification for low interest rate mortgages and by evidencing its market demand, the objective is to demonstrate that the product can have scalable impact for the 840,000 residents living in the ger districts.

Living with energy poverty: Uncovering older people’s fuel choices in urban China

Cities are front-runners and essential actors in the household energy transition from traditional solid to modern non-solid fuels. However, achieving an equitable and just transition in cities presents challenges, particularly for vulnerable populations. Among these vulnerable groups, older people are particularly affected by energy poverty, facing inadequate access to clean and modern energy. Yet, the linkages between their energy poverty and fuel choices remain underexplored, especially in urban areas outside the Global North context. This study focuses on China, a fastest-aging country, and aims to understand why some older people in affluent urban areas continue to burn honeycomb coal briquettes. By analyzing older people’s subjective experiences and objective connections to their fuel use, we uncover their lived experiences with energy poverty. We extended the ‘Energy Cultures Framework’ by including older people's vulnerability attributes alongside their material culture, norms, practices, and external influences. Using semi-structured interviews and participant observations in urban Wuhan, we found two patterns of dirty fuel stacking among older people facing energy poverty: passive and active dirty stacking. Passive dirty stacking is mainly caused by older energy-poor individuals' material culture, external influences, and vulnerability attributes; whereas active dirty stacking is primarily associated with their norms, practices, vulnerability attributes, and related external factors. Our findings provide strong implications for social and energy policy, particularly regarding the characterization of energy poverty, regulatory and infrastructural responses, social justice, grassroots governance, energy literacy, and cultural compatibility.

Comparison of Fracture and Permeability between Tectonically Deformed Coal and Briquette Coal using X-ray Computer Tomography and the Lattice Boltzmann Method

Comparison of Fracture and Permeability between Tectonically Deformed Coal and Briquette Coal using X-ray Computer Tomography and the Lattice Boltzmann Method

Effect of chemical structure on mechanical-seepage characteristics of briquette under different heating temperatures

Based on the low strength and high permeability of briquette coal (BC) used in physical simulations of coal mine disasters, we propose a new briquette production method that can improve the mechanical strength and reduce the permeability of BC. The reduction of physical simulation experiments of coal and gas outburst was improved, which is of significance for the prevention and control of coal mine gas disasters. Based on this method, we developed a set of briquette hot-pressing systems and optimized the proportion of coal powder used in the briquette formation process. Mechanical property and seepage tests of the briquettes were carried out under uniaxial and triaxial compression. The effects of different temperatures on the physical (size, density, ignition loss rate) and mechanical (Poisson's ratio, elastic modulus and compressive strength) coal parameters and the effect of the permeability were analyzed using scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy analyses. The morphology and pore, crystallite, and molecular structures were used to determine the cause of the increase in the mechanical strength of BC. Based on the packing density theory, the optimal ratio of the 40–60, 100–120, and 180–200 mesh particle sizes is 91.77:5.87:2.35. With the increase in the temperature from 150 to 450 °C, the microstructure changes from loose to compact, the number of pores and cracks increase, the degree of order of the microcrystalline structure gradually increases, the distance between the microcrystalline layers d002 continuously decreases, aliphatic chains shorten, and the aromaticity increases. The rate of the change of the loss rate and density of the hot-pressed briquette first increase, then decrease, and then increase again. The mechanical parameters (strength and elastic modulus) first increase and then decrease, whereas the Poisson's ratio first decreases and then increases, and the permeability increases. Considering the density, strength, and permeability of hot-pressed briquettes, the optimal heating temperature at which the similarity between the hot-pressed BC and raw coal is the highest at 300 °C.