Profile of CO2, CO, and H2 Emissions from Thermal Oxidation of Polish Coals

The self-heating phenomenon of coal leads to work safety hazards in underground mining. The quantitative analysis of gaseous products in mine atmosphere constitutes one of the detection methods of advanced coal heating. The article presents the results of tests on CO, CO2, and H2 emissions during simulated heating of coal in the temperature range of 323–523 K. The oxidation of 15 Polish coals of various carbon contents was performed using a flow reactor technique. A chromatography method was applied to measure the changes of oxidation products concentrations with the increase of temperature. It has been determined that all the tested gases were generated at the initial temperature. The collected data indicated that CO2 was a major oxidation product in the entire temperature range, while the amounts of H2 produced did not exceed 0.49% volume. At the temperature of 323 K, the ratio of CO2/CO was in the range of 10–23 but along with the temperature increase the ratio range narrowed to 3–4. In this paper, a comparison of the physical-chemical properties of the tested coals and the emissions profile of the gases using, among others, the hierarchical clustering analysis showed that samples with higher oxygen, sulfur, and inertinite content as well as lower ash and carbon content formed larger amounts of fire gases.

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Comparative TG/DTG/DTA+FTIR Studies Concerning the Stability of Some Mineral and Vegetable Electro-Insulating Fluids

Revista de Chimie ◽

10.37358/rc.18.9.6535 ◽

2018 ◽

Vol 69 (9) ◽

pp. 2366-2371

Author(s):

Andrei Cucos ◽

Petru Budrugeac ◽

Iosif Lingvay ◽

Adriana Mariana Bors ◽

Andreea Voina

Keyword(s):

Vegetable Oils ◽

Electrical Equipment ◽

Inert Atmosphere ◽

Oxidation Products ◽

Gaseous Products ◽

Mineral Oils ◽

Ftir Studies ◽

Dta Analysis ◽

Anti Oxidant ◽

The Stability

Thermal TG/DTG/DTA analysis coupled with FTIR spectroscopy was applied to some sorts of mineral and vegetable oils used in electrical equipment. On heating in inert atmosphere, it was observed that the mineral oils vaporize, while the vegetable oils undergo hydrolysis, yielding fatty acids as main volatiles, as indicated by FTIR. In synthetic air, the FTIR spectra of gaseous products confirm the presence of similar oxidation products, both for mineral and vegetable oils. The TG results indicated that the vegetable-based oils exhibit a substantially higher thermal stability than the mineral oils. The presence or absence of anti-oxidant inhibitors in these oils greatly influences the onset of the oxidation process in air environment factor, as results from the DTA results.

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Edge Computing for Data Anomaly Detection of Multi-Sensors in Underground Mining

Electronics ◽

10.3390/electronics10030302 ◽

2021 ◽

Vol 10 (3) ◽

pp. 302

Author(s):

Chunde Liu ◽

Xianli Su ◽

Chuanwen Li

Keyword(s):

Energy Consumption ◽

Anomaly Detection ◽

Underground Mining ◽

Heterogeneous Data ◽

Edge Computing ◽

Sensor Nodes ◽

Detection Methods ◽

Detection Accuracy ◽

Clustering Methods ◽

Safety Warning

There is a growing interest in safety warning of underground mining due to the huge threat being faced by those working in underground mining. Data acquisition of sensors based on Internet of Things (IoT) is currently the main method, but the data anomaly detection and analysis of multi-sensors is a challenging task: firstly, the data that are collected by different sensors of underground mining are heterogeneous; secondly, real-time is required for the data anomaly detection of safety warning. Currently, there are many anomaly detection methods, such as traditional clustering methods K-means and C-means. Meanwhile, Artificial Intelligence (AI) is widely used in data analysis and prediction. However, K-means and C-means cannot directly process heterogeneous data, and AI algorithms require equipment with high computing and storage capabilities. IoT equipment of underground mining cannot perform complex calculation due to the limitation of energy consumption. Therefore, many existing methods cannot be directly used for IoT applications in underground mining. In this paper, a multi-sensors data anomaly detection method based on edge computing is proposed. Firstly, an edge computing model is designed, and according to the computing capabilities of different types of devices, anomaly detection tasks are migrated to different edge devices, which solve the problem of insufficient computing capabilities of the devices. Secondly, according to the requirements of different anomaly detection tasks, edge anomaly detection algorithms for sensor nodes and sink nodes are designed respectively. Lastly, an experimental platform is built for performance comparison analysis, and the experimental results show that the proposed algorithm has better performance in anomaly detection accuracy, delay, and energy consumption.

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Large contribution to secondary organic aerosol from isoprene cloud chemistry

Science Advances ◽

10.1126/sciadv.abe2952 ◽

2021 ◽

Vol 7 (13) ◽

pp. eabe2952

Author(s):

Houssni Lamkaddam ◽

Josef Dommen ◽

Ananth Ranjithkumar ◽

Hamish Gordon ◽

Günther Wehrle ◽

...

Keyword(s):

Radiative Forcing ◽

Flow Reactor ◽

Secondary Organic Aerosol ◽

Cloud Droplet ◽

Organic Aerosol ◽

Global Scale ◽

Oxidation Products ◽

Oh Radicals ◽

Large Contribution ◽

Cloud Processing

Aerosols still present the largest uncertainty in estimating anthropogenic radiative forcing. Cloud processing is potentially important for secondary organic aerosol (SOA) formation, a major aerosol component: however, laboratory experiments fail to mimic this process under atmospherically relevant conditions. We developed a wetted-wall flow reactor to simulate aqueous-phase processing of isoprene oxidation products (iOP) in cloud droplets. We find that 50 to 70% (in moles) of iOP partition into the aqueous cloud phase, where they rapidly react with OH radicals, producing SOA with a molar yield of 0.45 after cloud droplet evaporation. Integrating our experimental results into a global model, we show that clouds effectively boost the amount of SOA. We conclude that, on a global scale, cloud processing of iOP produces 6.9 Tg of SOA per year or approximately 20% of the total biogenic SOA burden and is the main source of SOA in the mid-troposphere (4 to 6 km).

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Preparation of Ginger Oil in Water Nanoemulsion Using Phase Inversion Composition Technique: Effects of Stirring and Water Addition Rates on their Physico-Chemical Properties and Stability

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2019-1427 ◽

2019 ◽

Vol 0 (0) ◽

Author(s):

Ashraf Farshbaf-Sadigh ◽

Hoda Jafarizadeh-Malmiri ◽

Navideh Anarjan ◽

Yahya Najian

Keyword(s):

Particle Size ◽

Phase Inversion ◽

Antimicrobial Properties ◽

Chemical Properties ◽

Water Addition ◽

Chromatography Method ◽

Stirring Rate ◽

Physico Chemical ◽

Oil In Water ◽

Addition Rate

Abstract Ginger oil in water (O/W) nanoemulsions, were produced using phase inversion composition method and Tween 80, as emulsifier. Effects of processing parameters namely, stirring rate (100 to1000 rpm) and water addition rate (1–10 mL/min) were evaluated on the physico-chemical, morphological, antioxidant and antimicrobial properties of the prepared O/W nanoemulsions using response surface methodology (RSM). Results indicated that well dispersed and spherical ginger nanodroplets were formed in the nanoemulsions with minimum particle size (8.80 nm) and polydispersity index (PDI, 0.285) and maximum zeta potential value (−9.15 mV), using stirring rate and water addition rate of 736 rpm and 8.18 mL/min, respectively. Insignificant differences between predicted and experimental values of the response variables, indicated suitability of fitted models using RSM. Mean particle size of the prepared nanoemulsion using optimum conditions were changed from 8.81 ± 1 to 9.80 ± 1 nm, during 4 weeks of storage, which revealed high stability of the resulted ginger O/W nanoemulsion. High antioxidant activity (55.4%), bactericidal (against Streptococcus mutans) and fungicidal (against Aspergillus niger) activities of the prepared nanoemulsion could be related to the presence of gingerols and shogaols, a group of phenolic alkanones, in the ginger oil, which those were detected by gas chromatography method.

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POTENSI SENYAWA BIOAKTIF MESOCARP BUAH LONTAR (Borassus ﬂ abeliffer L.) SEBAGAI SUMBER ANTIOKSIDAN ALAMI (Potency of Mesocarp Bioactive Compounds in Lontar Fruit (Borassus ﬂ abeliffer L.) as A Source of Natural Antioxidant)

Jurnal Agritech ◽

10.22146/agritech.9455 ◽

2014 ◽

Vol 34 (03) ◽

pp. 277 ◽

Cited By ~ 1

Author(s):

Eny Idayati ◽

Suparmo Suparmo ◽

Purnama Darmadji

Keyword(s):

Bioactive Compounds ◽

Antioxidant Properties ◽

Chemical Properties ◽

Natural Antioxidants ◽

Chromatography Method ◽

Carotene Content ◽

Palm Fruit ◽

Dpph Method ◽

Total Fat ◽

Physical And Chemical

This study was aimed to characterize the physical and chemical properties of borassus palm fruit mesocarp, to determine the best type of solvent to extract bioactive compounds by maceration method, and to evaluate the antioxidant properties of bioactive compounds using DPPH (1,1-difenil-2-pikrilhidrazil) method. Carotenoid was separated based on TLC(thin layer chromatography) method, which produced spots. To conﬁ rm the results, the spots were scanned using UV-vis spectrofotometry. The results showed that the water content of borassus fruit mesocarp was 77.31%, while total fat, ash content, and tannin were 0.11%, 1.43%, 0.08%, respectively. Total Carotenoid was 8324.6 µg/100g with β carotene content was 6217.48 microgram/100g. The best solvent used in extracting the bioactive compounds was ethanol and acetone with (1:1) ratio. The highest yield was 4.3% and bioactive compounds in palm fruit mesocarpextracts as antioxidants was about 87% as carried out by DPPH method, so it could become a potential antioxidant. TLC Identiﬁ cation produced two spots. One spot was identiﬁ ed as carotenoids from xanthophyll group and the other one was β-carotene.Keywords: Natural antioxidants, borassus palm fruit mesocarp, bioactive compounds ABSTRAKPenelitian ini bertujuan untuk karakterisasi senyawa bioaktif dalam mesocarp buah lontar berdasarkan sifat ﬁsik dan kimia, mengetahui jenis pelarut terbaik untuk mengekstrak senyawa bioaktif dengan metode maserasi, serta mengevaluasi sifat antioksidan senyawa bioaktif mesocarp dengan metode DPPH (1,1-difenil-2-pikrilhidrazil). Dasarpemisahan karotenoid dengan metoda KLT (kromatograﬁ lapis tipis) pada ekstrak lalu dikuatkan dengan hasil scanning menggunakan spektrofotometer UV-Vis. Hasil penelitian menunjukkan bahwa mesocarp buah lontar mengandung kadar air 77,31%; total lemak 0,11%, kadar abu 1,43%; tanin 0,08%; total karotenoid 8324,6 µg/100g dengan kandungan senyawa karoten 6217,48 µg/100g. Perlakuan pelarut terbaik untuk proses ekstraksi senyawa bioaktif adalah etanol dan aseton dengan rasio (1:1). Hasil rendemen tertinggi yaitu 4,3% dan potensi senyawa bioaktif dalam ekstrak mesocarp buah lontar sebagai antioksidan dengan metode DPPH yaitu sekitar 87%, sehingga berpotensi sebagai salahsatu senyawa antioksidan. Identiﬁ kasi dengan metode KLT yang menghasilkan 2 noda yaitu noda 1 diduga karotenoid dari golongan xantoﬁ l dan noda 2 yatu karoten.Kata kunci: Antioksidan alami, mesocarp lontar, senyawa bioaktif

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Influence of hydrotalcite preparation conditions on its physico-chemical properties

Acta Chimica Slovaca ◽

10.2478/acs-2019-0017 ◽

2019 ◽

Vol 12 (1) ◽

pp. 119-126

Author(s):

Miroslava Mališová ◽

Michal Horňáček ◽

Pavol Hudec ◽

Jozef Mikulec ◽

Vladimír Jorík ◽

...

Keyword(s):

Catalytic Properties ◽

Chemical Properties ◽

Synthesis Temperature ◽

Optimal Synthesis ◽

Preparation Process ◽

Optimal Conditions ◽

Temperature Range ◽

Preparation Conditions ◽

Physico Chemical ◽

Ph Range

Abstract The aim of the research was to prepare and characterize hydrotalcite synthesized under different preparation conditions. The most common hydrotalcite preparation is the co-precipiaton method. The preparation process strongly influences the catalytic properties of hydrotalcite; therefore, optimal conditions have to be determined. During the study, seven samples of the catalyst were prepared in the pH range from 8 to 12 and the synthesis temperature range from 25 to 55 °C. Based on several catalyst properties, optimal synthesis pH 10 was found. Ideal temperature of the preparation was determined to be 35 °C, but the temperature does not have a significant effect on the catalyst properties.

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Influence of the Calcination Temperature on the properties of The Alumina as Catalyst Support for Catalysis

Paliva ◽

10.35933/paliva.2020.04.03 ◽

2020 ◽

pp. 155-161

Author(s):

Tomáš Hlinčík ◽

Veronika Šnajdrová ◽

Veronika Kyselová

Keyword(s):

Specific Surface ◽

Surface Area ◽

Calcination Temperature ◽

Specific Surface Area ◽

Catalyst Support ◽

Chemical Properties ◽

Total Pore Volume ◽

Temperature Range ◽

Calcination Temperatures ◽

Physical And Chemical

Alumina is commonly used in industrial practice as a catalyst support and it is made from boehmite. Depending on the calcination temperature, this mineral is transformed into various crystalline modifications which have different physical and chemical properties. For this reason, the following parameters were determined at different calcination temperatures: length, width, material hardness, specific surface area and total pore volume. The results show that with increasing calcination temperature there have been significant changes which may be important when using the material as a catalyst support, e.g. in the preparation of catalysts or in the design of cat-alytic reactors. The specific surface area, which decreases in the temperature range 450–800 °C, is an important parameter for the preparation of catalysts, so it is appropriate to choose a temperature of 600 °C, when the specific surface area is above 200 m2·g-1. The effect of calcination temperature on the structural transitions of boehmite was also monitored. The results showed that γ-Al2O3 has the most suitable properties as a catalyst sup-port in the temperature range 450–800 °C.

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Controlled nitric oxide production via O(<sup>1</sup>D)+N<sub>2</sub>O reactions for use in oxidation flow reactor studies

10.5194/amt-2016-394 ◽

2017 ◽

Author(s):

Andrew Lambe ◽

Paola Massoli ◽

Xuan Zhang ◽

Manjula Canagaratna ◽

John Nowak ◽

...

Keyword(s):

Nitric Oxide ◽

Flow Reactor ◽

Branching Ratio ◽

Oxidation Products ◽

Oh Radicals ◽

Ionization Mass ◽

Flow Reactors ◽

Oxidative Aging ◽

Gas Phase Oxidation

Abstract. Oxidation ﬂow reactors that use low-pressure mercury lamps to produce hydroxyl (OH) radicals are an emerging technique for studying the oxidative aging of organic aerosols. Here, ozone (O3) is photolyzed at 254 nm to produce O(1D) radicals, which react with water vapor to produce OH. However, the need to use parts-per-million levels of O3 hinders the ability of oxidation ﬂow reactors to simulate NOx-dependent SOA formation pathways. Simple addition of nitric oxide (NO) results in fast conversion of NOx (NO + NO2) to nitric acid (HNO3), making it impossible to sustain NO at levels that are sufﬁcient to compete with hydroperoxy (HO2) radicals as a sink for organic peroxy (RO2) radicals. We developed a new method that is well suited to the characterization of NOx-dependent SOA formation pathways in oxidation ﬂow reactors. NO and NO2 are produced via the reaction O(1D) + N2O→ 2NO, followed by the reaction NO + O3 → NO2+ O2. Laboratory measurements coupled with photochemical model simulations suggest that O(1D) + N2O reactions can be used to systematically vary the relative branching ratio of RO2 + NO reactions relative to RO2 + HO2 and/or RO2 + RO2 reactions over a range of conditions relevant to atmospheric SOA formation. We demonstrate proof of concept using high-resolution time-of-ﬂight chemical ionization mass spectrometer (HR-ToF-CIMS) measurements with nitrate (NO3−) reagent ion to detect gas-phase oxidation products of isoprene and α-pinene previously observed in NOx-inﬂuenced environments and in laboratory chamber experiments.

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In situ secondary organic aerosol formation from ambient pine forest air using an oxidation flow reactor

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-30409-2015 ◽

2015 ◽

Vol 15 (21) ◽

pp. 30409-30471 ◽

Cited By ~ 4

Author(s):

B. B. Palm ◽

P. Campuzano-Jost ◽

A. M. Ortega ◽

D. A. Day ◽

L. Kaser ◽

...

Keyword(s):

Organic Compounds ◽

Flow Reactor ◽

Secondary Organic Aerosol ◽

Ambient Air ◽

Organic Aerosol ◽

Pine Forest ◽

Oxidation Products ◽

Oh Radicals ◽

Aerosol Formation ◽

Photochemical Aging

Abstract. Ambient air was oxidized by OH radicals in an oxidation flow reactor (OFR) located in a montane pine forest during the BEACHON-RoMBAS campaign to study biogenic secondary organic aerosol (SOA) formation and aging. High OH concentrations and short residence times allowed for semi-continuous cycling through a large range of OH exposures ranging from hours to weeks of equivalent (eq.) atmospheric aging. A simple model is derived and used to account for the relative time scales of condensation of low volatility organic compounds (LVOCs) onto particles, condensational loss to the walls, and further reaction to produce volatile, non-condensing fragmentation products. More SOA production was observed in the OFR at nighttime (average 4 μg m-3 when LVOC fate corrected) compared to daytime (average 1 μg m-3 when LVOC fate corrected), with maximum formation observed at 0.4–1.5 eq. days of photochemical aging. SOA formation followed a similar diurnal pattern to monoterpenes, sesquiterpenes, and toluene + p-cymene concentrations, including a substantial increase just after sunrise at 07:00 LT. Higher photochemical aging (> 10 eq. days) led to a decrease in new SOA formation and a loss of preexisting OA due to heterogeneous oxidation followed by fragmentation and volatilization. When comparing two different commonly used methods of OH production in OFRs (OFR185 and OFR254), similar amounts of SOA formation were observed. We recommend the OFR185 mode for future forest studies. Concurrent gas-phase measurements of air after OH oxidation illustrate the decay of primary VOCs, production of small oxidized organic compounds, and net production at lower ages followed by net consumption of terpenoid oxidation products as photochemical age increased. New particle formation was observed in the reactor after oxidation, especially during times when precursor gas concentrations and SOA formation were largest. Approximately 6 times more SOA was formed in the reactor from OH oxidation than could be explained by the VOCs measured in ambient air. Several recently-developed instruments quantified ambient semi- and intermediate-volatility organic compounds (S/IVOCs) that were not detected by a PTR-TOF-MS. An SOA yield of 24–80 % from those compounds can explain the observed SOA, suggesting that these typically unmeasured S/IVOCs play a substantial role in ambient SOA formation. Our results allow ruling out condensation sticking coefficients much lower than 1. Our measurements help clarify the magnitude of SOA formation in forested environments, and demonstrate methods for interpretation of ambient OFR measurements.

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Analysis of physical, mechanical and chemical properties of seeds and kernels of Jatropha curcas

Research in Agricultural Engineering ◽

10.17221/10/2014-rae ◽

2016 ◽

Vol 61 (No. 3) ◽

pp. 99-105 ◽

Cited By ~ 1

Author(s):

M. Müller ◽

Š. Horníčková ◽

P. Hrabě ◽

J. Mařík

Keyword(s):

Fatty Acids ◽

Vitamin E ◽

Jatropha Curcas ◽

Unsaturated Fatty Acids ◽

Chemical Properties ◽

Acid Value ◽

Chromatography Method ◽

Value Determination ◽

And Chemical Properties

The research was performed to examine the physical, mechanical and chemical properties of seeds and kernels of Jatropha curcas. The test parameters were the dimensions of the seeds and kernels, required energy for oil extraction, determination of fatty acids in the oil by gas chromatography method, determination of the iodine value, determination of the acid value, determination of total polyphenols by the Folin & Ciocault reagent and determination of tocopherols and tocotrienols (vitamin E) by High-performance liquid chromatography. It was ascertained that the size of the seed and kernel varies considerably. Pressing of whole seeds needs more energy (50%) than pressing of kernels. From a chemical point of view it seems to be very appropriate for a production of biofuels. Jatropha curcas contains more polyphenols and vitamin E, which act as antioxidants, than the rape. Due to the low content of unsaturated fatty acids it is chemically suitable to replace the rape-seed oil with Jatropha curcas oil.

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