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The combustion of solid fuels, including coal and biomass, is a main anthropogenic source of atmospheric particulate matter (PM). The hidden costs have been underestimated due to lack of consideration of the toxicity of PM. Here we report the unequal toxicity of inhalable PM emitted from energy use in the residential sector and coal-fired power plants (CFPPs). The incomplete burning of solid fuels in household stoves generates much higher concentrations of carbonaceous matter, resulting in more than one order of magnitude greater toxicity than that from CFPPs. When compared with CFPPs, the residential sector consumed only a tenth of solid fuels in mainland China in 2017, but it contributed about 200-fold higher of the population-weighted toxic potency-adjusted PM 2.5 exposure risk. We suggest that PM 2.5 -related toxicity should be considered when making air pollution emission control strategies, and incomplete combustion sources should receive more policy attention to reduce exposure risks. Policy effort has been put into pollution reduction from both coal-fired electricity and domestic solid fuel burning in China; however, the former has attracted greater research and funding. Li and colleagues now show that the more toxic pollution from residential combustion may be responsible for greater health impacts than coal electricity.

Fluidized bed combustion of biomass requires maintaining stable properties of the inert bed material, which plays a key role in heat transfer, temperature stabilization and uniform fuel distribution in circulating fluidized bed (CFB) boilers. During long-term operation, quartz sand, i.e., the most commonly used inert material, undergoes physical and chemical degradation processes such as attrition, sintering and coating with alkali-rich ash, leading to changes in particle size distribution (PSD), deterioration of fluidization quality, temperature non-uniformities and an increased risk of bed agglomeration. This study analyzes quality management strategies for inert bed materials in biomass-fired CFB systems, with particular emphasis on the influence of PSD on boiler hydrodynamics and thermal behavior. Based on industrial operating data, sieve analyses and CFD simulations performed under representative operating conditions, a recommended mean particle diameter range of approximately 150–200 μm is identified as critical for maintaining stable circulation and uniform temperature fields. Numerical results demonstrate that deviations toward coarser bed materials significantly reduce solids circulation, promote segregation in the lower furnace region and lead to local temperature increases, thereby increasing agglomeration risk. The study further discusses practical approaches to bed material monitoring, regeneration and make-up management in relation to biomass type and ash characteristics. The results confirm that systematic control of inert bed material quality is an essential prerequisite for reliable, efficient and low-emission operation of biomass-fired CFB boilers.

Uni-modular charge has the advantages of easy automatic loading, fast loading speed, high safety and easy logistics support, which is the best choice for large calibre artillery charge. For uni-modular charge, the small number modular charge has some problems, such as ignition inequality, propellant combustion instability, and easy residue, which results in chamber pressure surge and low firing accuracy. Electrothermal plasma has the advantages of high temperature, high heat enthalpy and fast chamber diffusion, which is a feasible way to solve the problem of modular charge combustion. The key technologies such as plasma generator and high-power breech transmission have been studied, and the large calibre modular charge electrothermal chemical launch system has been established. Electrothermal chemical launch test was conducted. It is verified that electrothermal plasma can significantly enhance the firing performance of the small number modular charge.

Coal-fired power plants use coal as fuel, which will release a lot of mercury in the combustion process, directly threatening the ecological environment of the earth. In this study, a new adsorbent CuInSe2 with an active selenium site was prepared, which can effectively remove Hg0. The flower structure of the adsorbent with uniform distribution of selenium sites was confirmed by SEM characterization. Experimental results demonstrated that the adsorption efficiency was close to 99% at 80 ∼200°C, and the adsorption efficiency remained at a stable level of 92.39% even after continuous exposure for 6 hours. The equilibrium adsorption capacity was 18.64 mg/g. CuInSe2 has excellent resistance to SO2 and NO. In conclusion, CuInSe2 adsorbents possess significant potential for mercury removal, providing a new direction for the remediation of mercury pollution in various industrial waste gases using dual-metal selenide adsorbents.

The key factor affecting the combustion and operation of corner tangentially fired boilers (CTFBs) is the diameter of the imaginary circle. In this paper, the temperature and reducing gas distribution in a 350 MW supercritical CTFB were studied numerically, and the influence of imaginary circle diameter on combustion characteristics was analyzed. The results show that: 1) When the diameters of the imaginary circles of the primary and secondary air are decreased, there will be a delay in combustion. This is not profit to the steady-state burning of coal powder. In addition, the temperature near the water wall decreases, and the volume fraction of CO and H 2 S decreases on the rear side of the main combustion area, but increases significantly on the side of the fire. 2) By reducing only the diameter of the imaginary circle of primary air, the ignition distance of pulverized coal in the lower burner can be advanced, which is profit to improving combustion stability at low loads. Besides, the temperature, CO and H 2 S volume fraction near the water wall all decrease. 3) When the imaginary circle diameters of primary and secondary air in the upper part of the furnace are reduced, the temperature, volume fraction of CO and H 2 S in the adjacent layer near the water wall are increased.

This study offers a comprehensive comparative analysis of the elemental and proximate compositions of coal and biomass fuels, including Indo Coal, HBFL, SBP, and SBFL, highlighting their implications for sustainable energy production. Key elements such as aluminum, arsenic, boron, barium, calcium, chromium, copper, iron, potassium, lithium, magnesium, manganese, molybdenum, sodium, nickel, lead, antimony, silicon, and tin exhibit significant variations, emphasizing the importance of understanding each fuel source, particularly in co-firing applications. Combustion residues from these fuels show diverse elemental compositions, necessitating careful environmental management of elements like arsenic, lead, and chromium. Proximate analysis reveals distinctive characteristics, with variability in ash content affecting combustion efficiency and environmental considerations. The study finds that co-firing biomass with coal can significantly reduce NOx and SOx levels, with sulfur content in mixtures decreasing by up to 18%, leading to a potential 30% reduction in SO2 emissions. CO2 emissions could also be reduced by up to 51.21% as the biomass-to-coal ratio increases. Despite an 11% to 19% decrease in energy due to moisture imbalance, this can be optimized with technological advancements. Economic benefits are clear, as blending 2% of biomass can save 6.34% in both fuel consumption and purchase costs, with the highest cost-saving ratio of 72.87% achieved at a 20% blending ratio. Notably, most savings arise from the lower biomass purchase costs (Rs. 5000–6000 per ton) compared to coal (Rs. 15000–18000 per ton). However, technical challenges such as combustor fouling and corrosion from biomass ash must be addressed. Further research, particularly in thermal kinetic modeling, is recommended to examine the combustion characteristics of coal-biomass blends under controlled conditions. The progression from initial studies to long-term demonstrations indicates a promising future for co-firing technology, facilitating its widespread adoption in the industry at an optimal cost.

The effect of cylinder liners on engine performance is substantial. Typically, the cylinder surfaces were plateau honed. However, recently additional dimples or grooves were created on them. This work discusses the tribological impacts of textured cylinder liner surfaces based on a review of the literature. The results of the experimental research obtained using test rigs and fired engines were critically reviewed. In addition, the results of the modeling are shown. Circular oil pockets and grooves perpendicular to the sliding direction of piston rings of small depths were typically used. Surface texturing of the cylinder liners governs lubrication between the cylinder liner and the piston ring by an increase in oil film thickness near the reversal points leading to reductions in friction force and wear and in the fired engine to a decrease in fuel consumption and to an increase in power or torque. The correct texturing pattern ensures a decrease in the oil consumption, blow-by, and emissions of the internal combustion engine compared to plateau-honed surfaces. Considerations of future challenges are also addressed. The volume of lubricant reservoir in surface topography, called oil capacity, should be a substantial parameter characterizing textured surfaces.

Combustion of biomass, garbage, and fossil fuels in South Asia has led to poor air quality in the region and has uncertain climate forcing impacts. Online measurements of submicron aerosol (PM1) emissions were conducted as part of the Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) to investigate and report emission factors (EFs) and vacuum aerodynamic diameter (dva) size distributions from prevalent but poorly characterized combustion sources. The online aerosol instrumentation included a “mini” aerosol mass spectrometer (mAMS) and a dual-spot eight-channel aethalometer (AE33). The mAMS measured non-refractory PM1 mass, composition, and size. The AE33-measured black carbon (BC) mass and estimated light absorption at 370 nm due to organic aerosol or brown carbon. Complementary gas-phase measurements of carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4) were collected using a Picarro Inc. cavity ring-down spectrometer (CRDS) to calculate fuel-based EFs using the carbon mass balance approach. The investigated emission sources include open garbage burning, diesel-powered irrigation pumps, idling motorcycles, traditional cookstoves fueled with dung and wood, agricultural residue fires, and coal-fired brick-making kilns, all of which were tested in the field. Open-garbage-burning emissions, which included mixed refuse and segregated plastics, were found to have some of the largest PM1 EFs (3.77–19.8 g kg−1) and the highest variability of the investigated emission sources. Non-refractory organic aerosol (OA) size distributions measured by the mAMS from garbage-burning emissions were observed to have lognormal mode dva values ranging from 145 to 380 nm. Particle-phase hydrogen chloride (HCl) was observed from open garbage burning and was attributed to the burning of chlorinated plastics. Emissions from two diesel-powered irrigation pumps with different operational ages were tested during NAMaSTE. Organic aerosol and BC were the primary components of the emissions and the OA size distributions were centered at ∼80 nm dva. The older pump was observed to have significantly larger EFOA than the newer pump (5.18 g kg−1 compared to 0.45 g kg−1) and similar EFBC. Emissions from two distinct types of coal-fired brick-making kilns were investigated. The less advanced, intermittently fired clamp kiln was observed to have relatively large EFs of inorganic aerosol, including sulfate (0.48 g kg−1) and ammonium (0.17 g kg−1), compared to the other investigated emission sources. The clamp kiln was also observed to have the largest absorption Ångström exponent (AAE = 4) and organic carbon (OC) to BC ratio (OC : BC = 52). The continuously fired zigzag kiln was observed to have the largest fraction of sulfate emissions with an EFSO4 of 0.96 g kg−1. Non-refractory aerosol size distributions for the brick kilns were centered at ∼400 nm dva. The biomass burning samples were all observed to have significant fractions of OA and non-refractory chloride; based on the size distribution results, the chloride was mostly externally mixed from the OA. The dung-fueled traditional cookstoves were observed to emit ammonium, suggesting that the chloride emissions were partially neutralized. In addition to reporting EFs and size distributions, aerosol optical properties and mass ratios of OC to BC were investigated to make comparisons with other NAMaSTE results (i.e., online photoacoustic extinctiometer (PAX) and off-line filter based) and the existing literature. This work provides critical field measurements of aerosol emissions from important yet under-characterized combustion sources common to South Asia and the developing world.

Coal calorific value is one of the main considerations for using coal as a power plant fuel. In addition, the requirements for indications of slagging and fouling are also important to maintain combustion efficiency. However, coal power plants often experience problems in boiler operations due to the use of certain types of coal, even though they have a relatively high calorific value. This research investigates the effect of coal blending on ash fouling and slagging in an experimental investigation using a drop tube furnace with or without additives. Five different types of coal from different locations have been used in this study. Pulverized low-rank coal samples are burned in a drop tube furnace at 1,175°C with probe temperatures of 550°C and 600°C, corresponding to the combustion chamber of 600 MW power plants, including superheater and reheater areas. The ash particles’ characteristics and material composition were also analyzed using scanning electron microscopy with energy-dispersive X-ray (SEM-EDX) and X-ray diffraction (XRD), respectively. All coal mixture combinations demonstrated potential as a fuel for power plants that use pulverized coal-fired boilers. Because of its capacity to reduce slagging and fouling potentials, combining coal blending with the use of chemical additives yielded the greatest results.

Coal combustion is the largest source of power in India at the moment. This combustion also emits trace amounts of hazardous substances such as mercury. Mercury is a global pollutant with the potential for long-range transport and ability to persist in the environment, bioaccumulate and cause toxicity. Controlling emissions of mercury from coal-fired power plants (CFPPs) is recognized by the Minamata Convention on Mercury as an important step in curbing the harmful effects of mercury to the environment and humans. India has been identified as one of the top emitters of mercury to the atmosphere, and coal combustion contributes to more than half of these emissions. Here, we discuss the current state of regulations on mercury emissions from CFPPs in India, the current information on mercury from CFPP stacks, and the possible way forward. Present data suggest that mercury specific emission control technologies are not required to comply with the regulatory requirements. As such, any reduction in mercury emissions will rely on co-benefits obtained from technologies to control emissions of other pollutants such as flue gas desulphurization, or methods to increase the efficiencies of CFPP such as coal washing. Additional reductions may be made from a business-as-usual scenario if the energy mix of India changes to renewable non-fossil fuel-based energy at an accelerated pace. Quantitative studies assessing the role of such climate change policies on mercury emissions reduction are recommended.