Household Stoves Research Articles

Significant emission reductions of carbonaceous aerosols from residential coal burning by a novel stove

Carbonaceous aerosols (CA) are crucial components in the atmospheric PM2.5 and derived from diverse sources. One of the major sources for CA is from the incomplete combustion of bituminous coal that has been prevailingly used by household stoves in rural areas for heating during winter. To efficiently eliminate the CA emission, a new household stove (NHS) was developed based on a novel combustion technology and CA emissions from the NHS and a traditional household stove (THS) were comparably investigated under the actual stove operation conditions in a farmer's house. Compared with the THS, the emission factors of organic carbon (OC), elemental carbon (EC), and water-soluble organic carbon (WSOC) from the NHS were reduced by 96%±1%, 98%±1%, and 91%±1% under the flaming process and 95%±1%, 96%±2%, and 83%±4% under the smoldering process, respectively. Additionally, the mass absorption efficiency of WSOC from the NHS reduced by 3 folds and the radiative forcing by WSOC relative to EC shrank remarkably by a factor of 3-8. Based on the reduction of emissions and light absorption of WSOC, the promotion of the NHS offers a possible solution to achieve the clean combustion of residential solid fuel.

Assessing the indoor air pollution level as per energy ladder and its effect on respiratory health

In rural areas of developing countries, where about 40 % of all people live, the household stove accounts for more of all national fuel combustion occur under cooking pots. The present study was undertaken in Hisar district of Haryana state to assess the indoor air pollution level as per the energy ladder and its effect on respiratory health. The study was conducted in the rural villages of Hisar district and rural women who were using traditional chullah were selected as the sample of the study. Results revealed that most of the women were using chullah for cooking their own food and hara for animal feed with fuel placed on the lower rung of energy ladder i.e. crop waste and dung cakes, wood, kerosene, and LPG. Major health problems faced by women were ‘headache’ and ‘irritation in eyes’ while using the traditional chullah and hara. The majority of them were also having respiratory problems like ‘phlegm’ (mean score-2.7) ‘shortness of breath’ (mean score-2.6), ‘cough’ (mean score-2.5), and ‘wheezing’ (attacks) with mean score of 2.0, respectively. Mean PEFR values for the traditional chullah and hara exposed women were significantly lower as compared with MDV chullah and improved hara. Therefore, it is recommended that the use of cheap improved chullah and hara are the best alternative, which is the permanent solution of smoke and also consumes less fuel than traditional chullah and hara.

Toxic potency-adjusted control of air pollution for solid fuel combustion

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 PM2.5 exposure risk. We suggest that PM2.5-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.

Use of an integrated suite of sensors to simultaneously monitor fuel consumption, air quality, and adoption provides important insights and validates impact metrics for household stoves

The rise in sensor-based monitoring in the cookstove sector has been driven by the need for objective quantitative performance evaluation within context of use, and is especially useful if monitoring activities can be conducted by in-country project staff. This research explores the insights achievable from single and cross-sensor analysis following simultaneous in-home deployment of stove temperature loggers, weight-based fuel use loggers, and indoor PM concentration loggers deployed with remote guidance by researchers. Longitudinal performance metrics of an improved metal biomass stove with a chimney within its context of use were obtained using sensor suites consisting of stove temperature sensors (EXACT), household air pollution sensors (HAPEx), and fuel use sensors (FUEL) deployed in 48 households in the Taplejung and Panchthar districts of eastern Nepal. Households in the Taplejung district, comprised mostly of commercial tea houses, had a median reduction in daily household average PM concentration of 45.7% (n = 17) and a median reduction in logged household fuel use of 24.5%, or 2.17 kg/day (n = 15). Households in the Panchthar district comprised of smaller households had a median reduction in daily household average PM concentration of 64.5% (n = 19) and a median reduction in logged household fuel use of 8.13%, or 0.42 kg/day (n = 23). Cross-sensor analysis included use of household PM concentration to verify cooking event initiation and extraneous rises in PM outside of identified cooking events for potential exclusion. Household fuel use profiles were compared to known cooking events to determine whether a household had consistently interacted with the fuel measurement system as instructed, indicating which data were reliable and those that should be flagged. While both cross-sensor analysis and verification methods were examined as potential ways to obtain more information from the gathered data, further development of automated analytics platforms are needed before they can be used as reporting tools by project staff.

Influence of Molding Technology on Thermal Efficiencies and Pollutant Emissions from Household Solid Fuel Combustion during Cooking Activities in Chinese Rural Areas

Resident combustion of solid fuel has been widely acknowledged as a high potential for pollutant reduction. However, there is a marked asymmetry between more pollutant emission and less burned volatiles of biomass and coal in the combustion process. To study the solid fuel optimum combustion form in a household stove, both the pollution reduction and energy efficient utilization of crop straws and coals were investigated. Taking the molding pressure and clay addition ratio as variable process conditions, the research of bio-coal briquette (made from the mixture of anthracite and biomass) was implemented in the range of 15~35 MP and 5~15%, respectively. Biomass and coal work complementarily for each other’s combustion property development. In particular, the pyrolysis gas produced by biomass low-temperature devolatilization is featured with low ignition point and is distributed in the bio-coal briquette. Its own combustion provides energy for anthracite particle combustion. Consequently, a positive effect was identified when bio-coal briquettes were used as residential fuel, and further improvement manifested in reducing more than 90% of particle matter (PM) and achieving about twice the thermal efficiencies (TEs) compared with the mass-weighted average values of coal briquettes and biomass briquettes. 88.8 ± 11.8%, 136.7 ± 13.7% and 81.4 ± 17.7% more TEs were provided by wheat straw–coal briquettes, rice straw–coal briquettes and maize straw–coal briquettes. 93.3 ± 3.1% (wheat straw–coal), 97.6 ± 0.2% (rice straw–coal) and 90.4 ± 2.2% (maize straw–coal) in terms of PM2.5 emission factors (EFs) was reduced. For bio-coal briquette, a 25 MPa and 10% addition were determined as the optimum molding pressure and clay addition ratio. Bio-coal briquettes with higher TEs and lower PM EFs will bring about substantial benefits for air quality promotion, human health and energy saving.

Synergistic Health Benefits of Household Stove Upgrading and Energy Switching in Rural China.

Rural residential energy switching from solid fuels to electricity and natural gas has resulted in substantial health benefits in China. Here, we quantitatively estimated the environmental and health benefits of stove upgrading, energy switching, and the interaction of stove upgrading and energy switching in rural mainland China during the period of 1980-2014. Driven by government intervention, technical progress, and socioeconomic development, domestic stoves have been upgraded from a domination of open-fire and traditional stoves to energy-saving, clean stoves, and gas range/electric stoves. Furthermore, stove upgrading significantly contributed to the overall reductions in PM2.5 emissions (25%), ambient and indoor PM2.5 concentrations (49 and 28%), population exposure (31%), and premature deaths (37%) attributable to residential emissions. The interaction between stove upgrading and energy switching resulted in an additional 15% reduction in premature deaths. The influences of the residential sector and the beneficial effects of stove upgrading and energy switching are magnified along the causal path from emissions to health impacts. The overall benefit of the transition in residential energy would be substantially underestimated without considering stove upgrading.

An ultra-low-cost electroporator with microneedle electrodes (ePatch) for SARS-CoV-2 vaccination

Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other pathogens with pandemic potential requires safe, protective, inexpensive, and easily accessible vaccines that can be developed and manufactured rapidly at a large scale. DNA vaccines can achieve these criteria, but induction of strong immune responses has often required bulky, expensive electroporation devices. Here, we report an ultra-low-cost (<1 USD), handheld (<50 g) electroporation system utilizing a microneedle electrode array ("ePatch") for DNA vaccination against SARS-CoV-2. The low cost and small size are achieved by combining a thumb-operated piezoelectric pulser derived from a common household stove lighter that emits microsecond, bipolar, oscillatory electric pulses and a microneedle electrode array that targets delivery of high electric field strength pulses to the skin's epidermis. Antibody responses against SARS-CoV-2 induced by this electroporation system in mice were strong and enabled at least 10-fold dose sparing compared to conventional intramuscular or intradermal injection of the DNA vaccine. Vaccination was well tolerated with mild, transient effects on the skin. This ePatch system is easily portable, without any battery or other power source supply, offering an attractive, inexpensive approach for rapid and accessible DNA vaccination to combat COVID-19, as well as other epidemics.

Dispersion of particulate matter (PM&amp;lt;sub&amp;gt;2.5&amp;lt;/sub&amp;gt;) from wood combustion for residential heating: optimization of mitigation actions based on large-eddy simulations

Abstract. Many cities in the world experience significant air pollution from residential wood combustion. Such an advection–diffusion problem as applied to geographically distributed small-scale pollution sources presently does not have a satisfactory theoretical or modeling solution. For example, statistical models do not allow for pollution accumulation in local stagnation zones – a type of phenomena that is commonly observed over complex terrain. This study applies a Parallelized Atmospheric Large-eddy simulation Model (PALM) to investigate dynamical phenomena that control variability and pathways of the atmospheric pollution emitted by wood-burning household stoves. The model PALM runs at spatial resolution of 10 m in an urban-sized modeling domain of 29 km by 35 km with a real spatial distribution of the pollution source and with realistic surface boundary conditions that characterize a medium-sized urban area fragmented by water bodies and hills. Such complex geography is expected to favor local air quality hazards, which makes this study of general interest. The case study here is based on winter conditions in Bergen, Norway. We investigate the turbulent diffusion of a passive scalar associated with small-sized particles (PM2.5) emitted by household stoves. The study considers air pollution effects that could be observed under different policy scenarios of stove replacement; modern woodstoves emit significantly less PM2.5 than the older ones, but replacement of stoves is a costly and challenging process. We found significant accumulation of near-surface pollution in the local stagnation zones. The simulated concentrations were larger than the concentrations obtained only due to the local PM2.5 emission, thus indicating dominant transboundary contribution of pollutants for other districts. We demonstrate how the source of critical pollution can be attributed through model disaggregation of emission from specific districts. The study reveals a decisive role of local air circulations over complex terrain that makes high-resolution modeling indispensable for adequate management of the urban air quality. This modeling study has important policy-related implications. Uneven spatial distribution of the pollutants suggests prioritizing certain limited urban districts in policy scenarios. We show that focused efforts towards stove replacement in specific areas may have a dominant positive effect on the air quality in the whole municipality. The case study identifies urban districts where limited incentives would result in the strongest reduction of the population's exposure to PM2.5.

Combustion wastes from thermal power stations and household stoves: A comparison of properties, mineralogical and chemical composition, and element mobilization by water and fertilizers.

Wood and coal combustion generate wastes, which may negatively influence the environment. However, studies concerning coal combustion products serving as soil additives are currently in progress. Hence, this study was conducted to compare properties (mineralogy, metallic element content, and rare earth element content) of combustion wastes of different genesis (ash and soot after wood and coal combustion in households, ash from thermal power stations) and to assess possible risk posed to the soil environment when used as soil additive. This study demonstrated the diversity of chemical and mineralogical features of ashes of household genesis originating from thermal power stations. Ash from household stoves showed a higher concentration of metallic elements (i.e., Zn) compared to those originating from thermal power stations. Antimony (Sb) content in household ash can serve as an indicator of plastic (polyethylene) combustion, which is legally prohibited. Leaching tests using water and common mineral fertilizers showed that ammonium sulfate mobilizes metallic elements (Cu, Zn, Pb) more significantly than potassium nitrate or deionized water. The leaching of metallic elements from household stove's ash certainly excludes the possibility of applying the ash as a soil additive even when the ash contains a source of beneficial elements for plants (i.e., Ca).

Analysis of the influence of gas pressure on the parameters of its combustion in household gas stoves

In the gas supply system of Ukraine, gas appliances of domestic production are simultaneously operating, the manufacture of which took into account the requirements for parameters in our country and appliances manufactured in the countries of the European Union, where the requirements for the characteristics of gas are somewhat different. The first devices require a pressure of 1200-1300 Pa to ensure an optimal combustion process, and the second 2000-2500 Pa. The permissible minimum pressure in the distribution network can be significantly lower than required by gas equipment. Pressure control actually allows you to influence the efficiency of the gas combustion. A study of the change in the gas flow rate and the time of its combustion when heating a fixed volume of water at different pressures has been carried out. The study was carried out on household stoves from different manufacturers. The pressure range was from 1800 to 2600 Pa. The coefficients of change in the efficiency of gas use (δ) during the operation of the devices, depending on the pressure in front of the burners, have been determined. Based on the analysis of the results obtained, the optimal pressure was determined to be 2400 Pa. In this case, the minimum efficiency occurred at a pressure of 1800 Pa (deviation by 40%). At pressures of 2000 and 2500 Pa, on average, the deviation of the efficiency was 20%. The dependence of gas consumption on the intensity of its combustion was also analyzed. The experiments were carried out at constant pressure on burners of different power. It has been determined that when using a burner with a minimum power, the volume of gas used is reduced by 1,3 times with an increase in the heating time by about two times in comparison with a burner with a maximum power.

Environmental Contamination of Free-range Hen with Dioxin.

IntroductionThe transfer of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) from a contaminated environment into the food chain is a serious consumer safety problem. As part of the Polish National Surveillance Program of PCDD/Fs and PCBs in food of animal origin, a concentration of PCDD/Fs of 4.61 ± 0.75 pg WHO-TEQ/g fat was determined in a sample of free-range eggs, which exceeded the permitted limit of 2.5 pg WHO-TEQ/g. The aim of the study was to investigate the source of the egg contamination and the risk for the eggs’ consumers.Materials and methodsEggs, muscles, feed and soil from the place where backyard waste burning had been carried out in the past and ash from a household stove tipped onto the paddock were analysed using the isotope dilution technique with high-resolution gas chromatography coupled with high-resolution mass spectrometry.ResultsThe concentration in ash was low at 0.20 pg WHO-TEQ/g and the congener profile did not indicate the source of contamination. The dioxin content in soil from the backyard waste-burning site was 2.53 pg WHO-TEQ/g dry matter (d.m.) and the soil’s profile of PCDD/F congeners matched the profile of the contaminated eggs.ConclusionBy reason of the congener profile similarity, the investigation concluded, that the cause of the contamination was the backyard waste-burning site soil which the animals had access to. Frequent consumption of contaminated eggs from the analysed farm could pose a health risk due to chronic exposure, especially for vulnerable consumers.

Sulfur retention efficiency of clean coke produced by co-pyrolysis of coal with CaCO3 to substitute household coal

Raw coal is used by many suburban and rural households for cooking and heating and results in severe air pollution, especially problematic SO2 emissions. A source treatment strategy was proposed to reduce SO2 emissions, which used the co-pyrolysis of raw coal with a CaCO3 additive to produce clean coke. The effect of Ca/S molar ratio on the SO2 capture efficiency of clean coke was investigated, and the SO2 retention efficiency was optimized at a Ca/S molar ratio of 1.5. The sulfur retention mechanism of clean coke was attributed to: (1) CaCO3 decomposition to CaO and partial reaction of CaO with H2S to generate CaS during pyrolysis. (2) Transformation of the remaining sulfur in the clean coke to SO2 during combustion, capture by unreacted CaO to form CaSO4, and direct oxidation of CaS to CaSO4. The feasibility of SO2 emission reduction by clean coke in a practical household stove was verified.

Theoretical equilibration time is supported by measurement study of residence time at dilution sampling on fine particulate matter emissions from household biofuel burning

Household biofuel burning contributes a large proportion of fine particulate matter (PM2.5), black carbon (BC), and organic carbon (OC) emissions in many parts of the world. Dilution sampling has been widely used to characterize PM2.5 emitted from biofuel burning. The residence time in the dilution chamber is a key parameter for accurate sampling. However, residence time has not yet been adequately characterized for biomass combustion. In this work, we investigated the effects of residence time of dilution sampling on PM2.5 emissions from a typical Chinese household stove burning typical biofuels including three major crop wastes and one type of wood. The filter based measurements indicated that the emission factors for PM2.5 and its main chemical components such as OC, EC, Cl−, and K+ did not vary with the residence time over the range of 1–80 s. Theoretical estimation of average time scale for achieving dynamic equilibrium (τs) between the gas and particle phase in the dilution sampling system was less than 1 s. Both the measurement study and theoretical simulations indicated that dilution sampling with a residence time of 1s can provide adequately reliable results for PM2.5 emissions from biofuel burning under the condition of these experiments. A simple way to estimate the equilibration time based on measured average PM2.5 concentration was proposed. Recommendations are provided for the residence time for dilution sampling of accurate measurements of PM2.5 emissions from biofuel burning.

Features and problems of environmental pollution from decentralized heating systems (on the example of Chita)

This article is devoted to the study of the environmental load of decentralized energy facilities using the example of furnace heating in Chita. Existing residential and non-residential buildings heated with household stoves and low-power boilers increase the environmental burden on the environment. There are tendencies to switch to long-burning boilers. An analytical assessment of the change in the amount of emissions of the main pollutants when changing the operating modes of boilers is presented. Mechanisms for solving problems are proposed.

Monitoring of traditional stove use in the context of a clean fuel (liquefied petroleum gas, LPG) intervention trial in Guatemala, India, Peru, and Rwanda

Background: The Household Air Pollution Intervention Network (HAPIN) trial enrolled 3200 pregnant women who cooked with biomass fuel in Guatemala, India, Peru, and Rwanda; half were randomized to receive a liquefied petroleum gas (LPG) stove, approximately 18 months of free LPG, and behavioral messaging to promote LPG use. Although the intervention was designed to enable exclusive LPG use, investigators expected that some traditional stove use (TSU) would persist among intervention households. Methods: Thermocouple stove use monitors (SUMs, Geocene, Inc, Vallejo, USA) were installed on traditional stoves in intervention households. Data from SUMs were downloaded approximately every two weeks and TSU identified using a sensitive, deterministic algorithm. HAPIN fieldworkers visited households with detectable TSU events to administer a questionnaire on the reasons for TSU and reinforce exclusive LPG use. Results: Over 454,281 post-intervention household-days of monitoring among 1548 households (400 in Guatemala, 398 in India, 357 in Peru, and 393 in Rwanda), the rate of days with TSU per 100 household-days of observation was 0.83 (1.2 in Guatemala, 0.06 in India, 1.3 in Peru, and 0.8 in Rwanda). 95.1% of all households recorded one or no days with TSU on average per month (96.2% in Guatemala, 99.7% in India, 87.9% in Peru, and 95.9% in Rwanda). Primary reasons reported for TSU included: challenges with timely requests or receipt of LPG refills; resistance of other household members to LPG; uncertainty about how to clean, maintain, or check the LPG stove; and inability to cook large quantities of food with LPG. Conclusions: In the context of a free stove-and-fuel intervention combined with behavioral strategies to encourage exclusive LPG use, TSU events, measured by SUMs and direct observation, were infrequent at trial midpoint. The combination of SUMs data with household questionnaires provides a rich understanding of TSU persistence in the context of free LPG.

Environmental Characteristics of Modern Systems of Domestic Use of Fuel. Part 2. Pollutants Formation by Natural Gas Combustion in Atmospheric Burners: Experimental Studies

The Gas Institute of the National Academy of Sciences of Ukraine performs comprehensive studies of the formation of toxic emissions in the flame of atmospheric burners and beyond the visible burning cones (“rich” primary flame). The experiments are based on the proven significant content of harmful substances in the combustion products of gas fuel in household appliances and on direct contact of consumers with gas emissions during the operation of the stoves. A methodology for the experimental researches of the harmful emissions formation has been proposed while the computerized firing rig serving as the diagnostic facility has been developed for studying the combustion of hydrocarbon gases in the burners of household stoves. Carbon oxides CO and nitrogen oxides NO and NO2 are considered as toxic emissions, while the primary air excess coefficient and the heat load of the burner are considered as variable parameters. Under operating conditions of a gas stove, its variable characteristics are the gas pressure in front of the nozzle of the atmospheric burner and its thermal power. When optimizing the design of burners, the determinant value of the stability of burning, energy and environmental indicators of fuel combustion is the coefficient of excess of primary air λpr at a given gas pressure before the burner. The influence of this coefficient on the formation of CO, NO, NO2 is established, and the possibility of emissions with a high concentration of nitrogen dioxide is proved. Since the concentration of [NO] decreases with an increase in λpr, and the absolute level of [NO2] concentrations is not significantly affected by the value of λpr, it is determined that the proportion of [NO2] concentration in the [NOx] = [NO] + [NO2] compound increases with an increase in the primary air excess coefficient.

Size and chemical characteristics of particles emitted from typical rural biomass cookstoves in North China

The emission characteristics of biomass combustion in rural household stoves were measured in northern China. The Electrical Low-Pressure Impactor plus (ELPI+) was used to collect the emitted particles in the size range of 0.006–9.890 μm. The particle number concentration (PNC), particle mass concentration (PMC), and size distribution characteristics of organic carbon (OC), elemental carbon (EC), and water-soluble ions were analyzed. The experimental results showed that the PNC peaked at 0.006–0.030 μm, and the PMC peaked at 0.257–0.603 μm. The mass concentration of OC and EC exhibited a “bell-shaped” size distribution in the 0–10 μm range. The OC content of particles reached its peak at 0.006–0.016 μm and ranged from 25% to 38%. The mass concentration and percentage of K+ and Cl− showed “bell-shaped” size distribution characteristics and the contents of K+ and Cl− in each particle size group were significantly correlated. The chemical source profiles of PM0.1, PM1, PM2.5, and PM10 were constructed, whose main components were OC, EC, K+, and Cl−. PM2.5 profile included 8.39–20.27% OC, 1.94–20.96% EC, 0.25–13.36% K+, and 0.36–16.97% Cl−.

The effects of indoor air pollution from solid fuel use on cognitive function among middle-aged and older population in China

ObjectivesGrowing evidence has linked outdoor air pollution exposure with higher risk of cognitive impairments. However, the role of indoor air pollution in cognitive decline is not well elaborated. By using nationally representative longitudinal data, this study aimed to explore the effects of indoor air pollution from solid fuel use on cognitive function among middle-aged and older individuals in China. MethodsData were obtained from 2011 to 2015 waves of CHARLS (China Health and Retirement Longitudinal Study). Scores from the Telephone Interview of Cognitive Status and figure drawing/word recall tests were used to measure cognitive function in 39,482 individuals. Exposure to indoor air pollution was measured as use of solid fuel for cooking. Solid fuel was defined as coal, biomass charcoal, wood, and straw; clean fuel was defined as liquefied gas, natural gas, and electricity. Linear mixed effect models were applied to examine the effect of indoor air pollution from solid fuel use on cognitive function. ResultsParticipants had an average global cognitive function of 9.67 (SD = 4.13). Solid fuel users made up 49.71% of participants, but this proportion was much greater among those living in rural areas (64.22%). Compared with clean fuel users, solid fuel users had worse cognitive function. On average, solid fuel users had a 0.81 (95%CI: −0.89, −0.73) lower global cognition score, 0.63 (95%CI: −0.69, −0.57) lower mental health score, and 0.16 (95%CI: −0.22, −0.14) lower episodic memory score. These effects were stronger among participants who are female, aged 65 years old and above, have education level of primary school and below, or have cardiovascular diseases. ConclusionsThese results provide evidence for the role of indoor air pollution in neurobehavioral disorders in China. Promotion of practices like expanded use of clean fuel and improved stoves in households may be crucial to significantly reduce indoor air pollution and protect mental health.

Environmental Characteristics of Modern Systems of Domestic Use of Fuel. Part 1

The analysis of the environmental component of the processes of natural gas burning in atmospheric burners of domestic gas stoves has been carried out. The computational and experimental studies of the harmful substances formation by combustion of natural gas have been performed. The chemical equilibrium of the NO–O2–NO2 system was considered. The thermodynamic analysis of transformation of the system during a process of natural gas (methane-air mixture) combustion has been tested. Despite an essential (sometimes – by the order(s)) difference between the thermodynamically equilibrium concentration of the nitrogen oxides [NOx]eq and the local, actually measured values [NOx] = [NO] + [NO2], the [NO]eq values could be served as the qualitative indicators of actual values of [NOx] concentrations. In the combustion processes natural gas and other fuels combustion at high temperatures [NO] &gt;&gt; [NO2] for both equilibrium and measured concentrations. By moderate and low local temperatures up to 600 K the equilibrium concentration [NO2]eq → [NO]eq in order of magnitude. Under some compositions of burning mixture the correlation could be set as [NO2] &gt;&gt; [NO], resulting in great danger for the human health. With regard to the formation of particularly toxic NO2 effluents observed in some cases, an influence of the reaction temperature and the composition of the combustible mixture on the possibility of nitrogen dioxide formation in the combustion products have been analyzed. A methodology for the experimental study of the harmful emissions formation has been proposed while the computerized firing rig has been developed for studying the combustion of hydrocarbon gases in burners of household stoves. An influence of the coefficient of primary air excess on the СО, NO, NO2 formation has been revealed and the possibility of appearance the emissions of a high concentration of nitrogen dioxide has been demonstrated.

Co-pyrolysis and synergistic effect analysis of biomass sawdust and polystyrene mixtures for production of high-quality bio-oils

Usage of traditional biomass raises serious concerns regarding its sustainability due to the inefficient combustion in household stoves and potential over-usage if the intention is to replace fossil fuels in power plants. Co-pyrolysis of biomass feedstock with different waste materials, especially plastics, might be a promising alternative for sustainable usage of enhanced biofuels. Even more, co-pyrolysis can help to integrate waste management schemes into the power production sector. Plastics materials have properties similar to those of fossil fuels in terms of heating value and the absence of oxygenated compounds; therefore, they could significantly improve the properties of biomass products, especially bio-oils. Especially interesting for this method is polystyrene (PS) since it yields a high share of liquid fraction, which is the most valuable pyrolytic product. In this work, co-pyrolysis was performed for a mixture of waste biomass sawdust (oak, poplar and fir wood) and waste polystyrene from dairy product packaging. Pyrolysis was carried out for sawdust and polystyrene alone, and their respective fuel blends (PS/SD 25−75%, PS/SD 50−50%, PS/SD 75−25%) from room temperature to 600°C with a retention time of half an hour. The highest yield of liquid fraction was noticed for mixtures with 75 % of PS, while the lowest one was for blends with 25 % of PS, with a yield of 83.86 % and 62.33 %, respectively. Additionally, the mass spectrometric analysis was carried out to determine the chemical composition of the obtained oil.