Content Of Volatile Substances Research Articles

A Study of Condensates Collected during the Fermentation of Grape Must

This article deals with the analysis of the condensates which are formed from fermentation gases during the fermentation of grape must. The experiment was divided into two parts. In the first part, the evolution of the individual volatiles was monitored throughout the whole fermentation process of the Riesling variety. In the second part, the condensates from three different grape varieties (Riesling, Merlot, Sauvignon blanc) were investigated and the total content of the selected volatile substances was measured at the end of the fermentation. Attention was focused on the measurements using a GC-MS (gas chromatography-mass spectrometry) for the volatile substances: isoamyl alcohol, isobutyl alcohol, 1-propanol, ethyl acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, acetaldehyde, acetic acid, and acetoin. In addition, changes in the alcohol content of the condensate, with respect to the fermentation phase, were analysed. From the results of part 1, the quantity of the substances under investigation produced during fermentation was determined. The highest concentration of flavour compounds was during the fourth and fifth days of fermentation. The most dominant substance was isoamyl alcohol with a concentration of 1267 mg−1.The results of part 2 led to a comparison of the overall profile of volatiles between the varieties. The results showed that the condensates have both a high content of volatile substances and of alcohol. It was also shown that the Sauvignon blanc variant had the highest number of volatile compounds in the representation. The Merlot and Riesling variants were very similar. This product has an exceptionally high potential for further use in the wine or food industry.

Pyrolysis characteristics and kinetics of waste photovoltaic module: A TG-MS-FTIR study

The emerging application of solar power plants has led to serious waste photovoltaic module disposal problems. To address the environmental concerns associated with waste photovoltaic module disposal, this study investigates pyrolysis as a promising treatment technology and a fundamental step for various thermal chemical processes. The kinetic characteristics and pyrolysis products of ethylene vinyl acetate (EVA), Tedlar-Polyethylene Terephalate-Tedlar (TPT), and silica gel were studied using TG-FTIR-MS. The weight loss stages of EVA, TPT, and silica gel were between 300 and 510 °C, 330–520 °C, and 100–830 °C, respectively, with a total weight loss rate of 99–100%, 73–76%, and 60–62%. The reactions they experienced were acetic acid production and long chain fracture, long chain fracture and fluorocarbon compound production, polymer methyl vibration, [(CH3)2SiO] cyclic compound production, Si–C bond fracture, and CO2 production, respectively. According to the results of the two kinetic models, their average activation energies were 278-281 kJ/mol, 330-336 kJ/mol, and 187-193 kJ/mol. The products released during the pyrolysis process of the three samples were different. Among them, olefins and aromatic hydrocarbons from EVA and TPT could be used to synthesize high-molecular-weight substances. Aldehydes, fats, and esters from TPT could be used to synthesize drugs and daily necessities; hydrofluoric acid and furan were harmful to human health and the environment. Hexamethylcyclotrisiloxane and octamethylcyclotetrasiloxane from silica gel could be used to synthesize silicone polymers. The content of volatile substances during pyrolysis was related to the heating rate. The findings are expected to contribute to the development of waste photovoltaic module disposal and resource recovery through pyrolysis.

Exposure limits for indoor volatile substances concerning the general population: The role of population-based differences in sensory irritation of the eyes and airways for assessment factors.

Assessment factors (AFs) are essential in the derivation of occupational exposure limits (OELs) and indoor air quality guidelines. The factors shall accommodate differences in sensitivity between subgroups, i.e., workers, healthy and sick people, and occupational exposure versus life-long exposure for the general population. Derivation of AFs itself is based on empirical knowledge from human and animal exposure studies with immanent uncertainty in the empirical evidence due to knowledge gaps and experimental reliability. Sensory irritation in the eyes and airways constitute about 30-40% of OELs and is an abundant symptom in non-industrial buildings characterizing the indoor air quality and general health. Intraspecies differences between subgroups of the general population should be quantified for the proposal of more 'empirical' based AFs. In this review, we focus on sensitivity differences in sensory irritation about gender, age, health status, and vulnerability in people, based solely on human exposure studies. Females are more sensitive to sensory irritation than males for few volatile substances. Older people appear less sensitive than younger ones. However, impaired defense mechanisms may increase vulnerability in the long term. Empirical evidence of sensory irritation in children is rare and limited to children down to the age of six years. Studies of the nervous system in children compared to adults suggest a higher sensitivity in children; however, some defense mechanisms are more efficient in children than in adults. Usually, exposure studies are performed with healthy subjects. Exposure studies with sick people are not representative due to the deselection of subjects with moderate or severe eye or airway diseases, which likely underestimates the sensitivity of the group of people with diseases. Psychological characterization like personality factors shows that concentrations of volatile substances far below their sensory irritation thresholds may influence the sensitivity, in part biased by odor perception. Thus, the protection of people with extreme personality traits is not feasible by an AF and other mitigation strategies are required. The available empirical evidence comprising age, lifestyle, and health supports an AF of not greater than up to 2 for sensory irritation. Further, general AFs are discouraged for derivation, rather substance-specific derivation of AFs is recommended based on the risk assessment of empirical data, deposition in the airways depending on the substance's water solubility and compensating for knowledge and experimental gaps. Modeling of sensory irritation would be a better 'empirical' starting point for derivation of AFs for children, older, and sick people, as human exposure studies are not possible (due to ethical reasons) or not generalizable (due to self-selection). Dedicated AFs may be derived for environments where dry air, high room temperature, and visually demanding tasks aggravate the eyes or airways than for places in which the workload is balanced, while indoor playgrounds might need other AFs due to physical workload and affected groups of the general population.

Chemical composition and antimicrobial activity of Rosa Damascena mill. (variety rainbow) from clonal micropropagation

Damask rose of the Veselka variety is an important industrial rose variety used to obtain essential oil. It is widely used in modern cosmetology, perfumery, and aromatherapy. In addition, the essential oil of Damask rose has a whole spectrum of pharmacological properties.
 The scientific innovation of this research lies in its foundation on cultivating and acquiring planting materials of the Damask rose in vitro. This approach guarantees controlled conditions for plant growth, the production of robust seedlings, and an enhancement in the precision and credibility of the research outcomes.
 Moreover, the study has scientific novelty in that it explores to assess both the quantitative and qualitative constituents of the essential oil in the acquired plant material of the Damask rose. This assessment takes place within the context of cultivating regenerative plants in an outdoor environment. Such an approach acknowledges the potential distinctions in the oil's component composition acquired from plants propagated through this method in comparison to traditional vegetative reproduction. Lastly, the research has scientific novelty in investigating the potential antimicrobial properties of Damask rose essential oil, which could have significant practical implications in the development of new drugs and combatting infectious diseases.
 The purpose of the study was to establish the component composition of the essential oil of Rosa damascena Mill., which was grown in vitro, and to determine its antimicrobial effect.
 Methods. The object of the study was the essential oil of Damask rose of the Veselka variety, which was grown by the method of clonal micropropagation in vitro. The essential oil was extracted from fresh petals collected during dry weather conditions prior to sunrise by hydrodistillation. Determination of the qualitative composition and quantitative content of volatile substances was carried out by the GC-MS method using an Agilent 7890B chromatograph. Antimicrobial activity was studied in vitro using the disk diffusion method with reference test strains of microorganisms Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, Candida albicans ATCC 885-653.
 Results. According to the results of the chromato-mass spectrometric study, 41 compounds (6 of which were in the isomeric state) were identified, which was belong to 13 different classes of chemicals. Dominant compounds among terpenoid substances were shown: geraniol – 30.96 %, citronellol – 27.08 %, alkanes: nonadecane – 17.29 %, and heneicosene – 5.46 %.
 It was established that the essential oil of Damask rose had a significant antimicrobial effect against strains of C. albicans and E. coli, the diameters of which growth retardation zones ranged from 32-35 mm and 20-23 mm, respectively. In studies with P. aeruginosa and S. aureus, the essential oil showed moderate antibacterial activity: the diameters of the growth retardation zone of these microorganisms ranged from 13 to 15 mm and 11 to 12 mm, respectively.
 Conclusion. For the first time, the qualitative composition and quantitative content of volatile substances in the essential oil extracted from the petals of Rosa damascena Mill., Veselka variety, cultivated through the clonal micropropagation in vitro, were explored by chromatography-mass spectrometry techniques. The results of the study of antimicrobial activity showed that the studied essential oil exhibits significant fungicidal effects against Candida microorganisms, along with moderate bactericidal effects on gram-negative (E. coli, P. aeruginosa) and gram-positive (S. Aureus) bacteria. These results highlight the potential of this essential oil for further investigation in the realm of developing novel medicines and herbal preparations. Further clinical studies are needed to assess this potential.

Application a solid fuel mixture based on Bolshesyrsky lignite and birch wood waste in power plants

In this paper, we investigate the possibility of using a solid fuel mixture based on lignite from the Bolshesyrsky coal mine and birch wood waste in power plants, taking synergistic interactions between the mixture components into account. Simultaneous thermal analysis was used to determine the main combustion characteristics of lignite, biomass and their mixtures. Non-isothermal heating was performed at a rate of 20°C/min across the temperature range of 25–800°C under the air flow of 50 ml/min. The sample weight was about 6 mg. Proximate and elemental analyses of lignite and biomass samples were performed according to conventional methods. The advantages and disadvantages of converting power plants operated on solid fossil fuels to a solid fuel mixture of lignite and biomass are discussed. The main combustion characteristics of lignite, biomass and their mixtures were defined. The ignition temperature of the coke residue and biomass was found to comprise 365 and 299°C, respectively. The temperature of combustion completion for lignite and biomass was 551 and 464°C, respectively. In comparison with lignite, biomass burns at lower temperatures due to the high content of volatile substances. The addition of biomass to lignite was found to reduce both the ignition temperature of the coke residue and that of combustion completion. An analysis of the combustion process of volatile substances and coke residue established the presence of both positive and negative synergistic interactions between lignite and biomass particles, affecting the maximum combustion rate and the mixture reactivity. The results obtained can be applied when designing power plants operated on solid fuel mixtures of lignite and biomass.

Evaluation of 60Co Irradiation on Volatile Components of Turmeric (Curcumae Longae Rhizoma) Volatile Oil with GC-IMS.

60Co irradiation is an efficient and rapid sterilization method. The aim of this work is to determine the changes in essential-oil composition under different irradiation intensities of 60Co and to select an appropriate irradiation dose with GC-IMS. Dosages of 0, 5, and 10 kGy of 60Co were used to analyze turmeric (Curcumae Longae Rhizoma) volatile oil after 60Co irradiation (named JH-1, JH-2, and JH-3). The odor fingerprints of volatile organic compounds in different turmeric volatile oil samples were constructed by headspace solid-phase microextraction and gas chromatography-ion mobility spectrometry (GC-IMS) after irradiation. The differences in odor fingerprints of volatile organic compounds (VOCs) were compared by principal component analysis (PCA). The results showed that 97 volatile components were detected in the volatile oil of Curcuma longa, and 64 components were identified by database retrieval. With the change in irradiation intensity, the volatile compounds in the three turmeric volatile oil samples were similar, but the peak intensity was significantly different, which was attributed to the change in compound composition and content caused by different irradiation doses. In addition, the principal component analysis showed that JH-2 and JH-3 were relatively correlated, while JH-1 and JH-3 were far from each other. In general, different doses of 60Co irradiation can affect the content of volatile substances in turmeric volatile oil. With the increase in irradiation dose, the peak area decreased, and so the irradiation dose of 5 kGy/min was better. It is shown that irradiation technology has good application prospects in the sterilization of foods with volatile components. However, we must pay attention to the changes in radiation dose and chemical composition.

Effects of poly(vinyl alcohol) matrix on the release of substances from the fragrance composition

The chemical composition of two commercially available lavender fragrance oils was determined and compared. The process of concentration by partial evaporation was carried out and its influence on changes in the content of individual components in the analysed mixtures was examined. The effect of poly(vinyl alcohol)-based polymer matrix on the release of volatile substances from oils was tested as well. The presence and chemical composition of the polymer matrix affects the relative content of volatile substances released from the liquid phase containing the tested fragrance composition.

Effect of Fat to Lean Meat Ratios on the Formation of Volatile Compounds in Mutton Shashliks.

This study aimed to investigate the release of volatile compounds in mutton shashliks (named as FxLy, x-fat cubes: 0-4; y-lean cubes: 4-0) with different fat-lean ratios before and during consumption, respectively. In total, 67 volatile compounds were identified in shashliks using gas chromatography/mass spectrometry. Aldehyde, alcohol, and ketone were the major volatile substances, accounting for more than 75% of the total volatile compounds. There were significant differences in the volatile compounds of mutton shashliks with different fat-lean ratios. With the increase of the fat content, the types and content of volatile substances released also increase. However, when the percentage of fat exceeded 50%, the number of furans and pyrazine, which were characteristic of the volatile compounds of roasted meat, was decreased. The release of volatiles during the consumption of mutton shashliks was measured using the exhaled breath test and the results showed that adding an appropriate amount of fat (<50%) helps to enrich the volatile compound components in the mouth. However, shashliks with higher fat-lean ratios (>2:2) shorten the mastication duration and weaken the breakdown of bolus particles in the consumption process, which is not conducive to the release potential of volatile substances. Therefore, setting the fat to lean ratio to 2:2 is the best choice for making mutton shashliks, as it (F2L2) can provide rich flavor substances for mutton shashliks before and during consumption.

Prospective Plant Raw Materials for New Fermented Beverages

Topicality. The relevance of this research grounds on the fact that fermented drinks are gaining huge popularity nowadays due to their competitive advantages, including improving the immune system and gut health. Expanding the assortment of plant raw materials in the composition of fermented drinks will allow to create a whole range of new health products that will interest the consumer. The aim of the article. The aim of this study is a selection of promising raw materials for the production of fermented beverages and getting the methods of their processing. Research methods. Standard organoleptic, physico-chemical and chromatographic research methods were used in this article. Results. The conducted studies established that the highest content of volatile substances among the researched plants is lemon verbena (1074.5 mg per 100 g of dry matter), varieties and hybrids of mint with a “dessert” aroma (chocolate – 987.0, orange – 982.7 and strawberry – 975.2 mg per 100 g of dry matter), as well as Tibetan Lofant (834.8 mg per 100 g of dry weight). This provides them with a high potential for use in the production of fermented beverages. Other studied plants also have the prospect of being used in the production of drinks with a specific taste or aroma due to their pleasant scent and high content of volatile substances (782.8 – 934.4 mg per 100 g of dry matter). A decrease in the oxidative and restorative potential indicator of selected plants extracts, compared to water, indicates the presence of substances with antioxidant activity. The high potential of such an activity was found in spicy-aromatic plants: wild strawberry leaves, Chinese lemongrass, hazel, Bacopa Monier, chokeberry and common horsetail. Conclusions and discussion. It was proven that the most promising method of obtaining the basis for fermented drinks is an extraction, while hydrolats and distillates should be used as natural flavoring agents and disinfectants. The results of this study can serve as a ground for the production technologies development of new fermented beverages.

HS-SPME coupled with GC-MS for elucidating differences between the volatile components in wild and cultivated Atractylodes chinensis.

Atractylodes chinensis is a Chinese herb that is used in traditional medicine; it contains volatile components that have enormous potential for pharmaceutical, food, and cosmetic applications. The destruction of wild resources demands significant improvement in the quality of artificial cultivation of Atractylodes chinensis. However, little is known about the compositional differences in the volatile substances derived from the wild and cultivated varieties of Atractylodes chinensis. We aimed to evaluate the specific components of Atractylodes chinensis and analyse the similarities and differences between the volatile components and metabolic pathways in the wild and cultivated varieties. Metabolomic analysis using gas chromatography-mass spectrometry (GC-MS) was employed following the extraction of volatile components from Atractylodes chinensis using headspace solid-phase microextraction (HS-SPME). A total of 167 volatile metabolites were extracted, and 137 substances were matched with NIST and Wiley databases. Among them, 76 compounds exhibited significant differences between the two sources; these mainly included terpenes, aromatics, and esters. KEGG enrichment analysis indicated that the differential metabolites were primarily involved in the biosynthesis of secondary metabolites, terpene biosynthesis, and limonene and pinene degradation; all these pathways have geranyl diphosphate (GDP) as the common link. The total content of volatile substances extracted from wild Atractylodes chinensis was 2.5 times higher than that from the cultured variety; however, each source had different dominant metabolites. This study underscores the necessity for protecting wild Atractylodes chinensis resources, while enhancing the quality of cultivated Atractylodes chinensis.

The New Insight into the Effects of Different Fixing Technology on Flavor and Bioactivities of Orange Dark Tea.

Peach leaf orange dark tea (ODT) is a fruity tea made by removing the pulp from peach leaf orange and placing dry Qingzhuan tea into the husk, followed by fixing them together and drying. Since the quality of traditional outdoor sunlight fixing (SL) is affected by weather instability, this study explored the feasibility of two new fixing methods, including hot air fixing (HA) and steam fixing (ST). Results showed that fixing method had a great impact on ODT shape, aroma, and taste. Compared with SL and ST, HA endowed ODT with higher fruit aroma, mellow taste, better coordination, and higher sensory evaluation score. Physical-chemical composition analysis showed that SL-fixed orange peel was higher than HA- or ST-fixed peel in the content of polyphenols, flavonoids, soluble protein, hesperidin and limonin, while HA has a higher content of volatile substances and contains more alcohols, aldehydes and ketones, and acid and esters than ST and SL. Activity analysis showed that HA was superior to ST or SL in comprehensive antioxidant activity and inhibitory activity against α-glucosidase. Comprehensive results demonstrated that HA has better performance in improving ODT quality and can replace the traditional SL method in production.

Influence on the aroma substances and functional ingredients of apple juice by lactic acid bacteria fermentation

This study aimed to analyze the influence of lactic acid bacteria fermentation on the aroma composition and functional composition of apple juice, selected Lactobacillus reuteri to ferment apple juice, used HS-SPME-GC-MS and HPLC to analyze the changes of volatile aroma composition, organic acids and phenols after fermentation. The results showed the best fermentation time was about 18 h; The type and content of volatile substances (mainly alcohols and esters) in fermented juice changed and affected the overall aroma; The content of organic acids such as succinic acid, tartaric acid, malic acid and pyruvic acid affected the taste and flavor; The content of polyphenols such as gallic acid and protocatechuic acid increased, which enhanced the antioxidant capacity and functionality of fermented juice. This result showed the positive effect of fermentation on juice and provided a reference for the subsequent research on the aroma and functional composition of apple juice.

Release effect of aroma compounds of Keemun black tea brewed with deuterium-depleted water with different deuterium content

Keemun black tea (KBT) is one of the four famous black teas in the world. This work was the first to explore the interaction between deuterium-depleted water (DDW) and black tea. In this study, stir bar sorptive extraction (SBSE) and gas chromatography-mass spectrometry were used to determine the content of volatile substances in KBT in DDW containing deuterium (D) at a concentration of 40 parts per million (ppm), 70 ppm and the control at 150 ppm. Results indicated that there were 20 compounds (aroma activity value (OAVs) ≥ 1) in KBT which were identified as important substances, of which there were eight key aroma compounds (OAVs ≥10). Compared with the content and OAVs of aroma substances in natural water, water with a deuterium content of 40 ppm promoted the release of aroma substances, while the other water inhibited their release. This study is expected to provide theoretical guidance for the application of DDW among tea connoisseurs.

An Efficient Processing Strategy to Improve the Flavor Profile of Egg Yolk: Ozone-Mediated Oxidation.

This study investigated the effect of ozone treatment on egg yolk volatiles and fatty acids. The composition and content of volatile substances and the fatty acid content of the egg yolk were changed significantly after ozonation. With proper ozone treatment (30 min), the aldehyde content in the egg yolk increased from 78.08% to 94.63%, and the relative content of dibutyl amine decreased from 1.50% to 0.00%. There were no significant differences among the types of fatty acids in the egg yolks after being treated with ozone, but there were differences in their relative contents. The results of SDS-PAGE showed no significant difference in yolk protein composition and contents among the groups. SEM results showed that moderate ozone treatment (20 min and 30 min) led to a regular and dense network structure of egg yolk. These results provided a theoretical basis for expanding the application of ozone technology in the egg yolk processing industry.

Petroleum coking additive - raw material component for metallurgical coke production. Part 2. Experimental studies of obtaining a petroleum coking additive

Petroleum coke is a potential partial replacement of coking coals (being in short supply) in manufacture of metallurgical coke; in Russia and other CIS countries it was entitled as petroleum coking additive (PCA), petroleum coke with output of volatile substances within the range 15-25 %. The second part of the work describes the results of conducted experimental researches in the field of manufacture of petroleum coke additive on the example of use of two kinds of sulfuric petroleum residues of &ldquo;KINEF&rdquo; JSC as raw materials: residue of atmospheric distillation and mixture of residues of vacuum distillation and visbreaking. The research was conducted for two temperature procedures within the ranges 455-465 and 475-485 &deg;С. Eight samples of carbon material were obtained as a result of conversion, and influence of input parameters of the coking process on composition and physical-chemical properties of obtained carbon materials was established. Based on content of volatile substances in petroleum coke additive and its group chemical composition, which was determined via extraction method (content of &alpha;-, &beta;- and &gamma;-fractions) and via infrared Fourier spectroscopy, assessment and ranging of the eight obtained PCA samples were carried out by their sintering susceptibility. Interpretation of infrared spectra of obtained PCA samples was conducted via comparison with infrared spectra of coking coal, which have identical absorption stripes. Relation between PCA sintering ability and procedure parameters of the coking process was revealed. It was determined that technological process occurring at the less coking temperature 455-465 &deg;С provides high quality PCA forming, otherwise the procedure with higher temperature (475-485 &deg;С). This work was carried out as part of the State Assignment&nbsp;0792-2020-0010 &ldquo;Development of scientific foundations of&nbsp;innovative technologies for processing heavy hydrocarbon&nbsp;raw materials into environmentally friendly motor fuels and&nbsp;new carbon materials with controlled macro- and microstructural&nbsp;organization of mesophase&rdquo;.

Petroleum coking additive is a raw material for production of metallurgical coke. Part 1. Formation of sintering properties of petroleum coking additive (review)

A significant proportion of the entire mass of waste from the oil refining industry is accounted for heavy sour oil residues, and one of the most common solutions in the world is the recycling of these wastes to obtain petroleum cokes. However, the high sulfur content often does not allow to find a qualified application and a market for the obtained sulfide carbon materials. In this work, a review of the scientific and technical literature on the industrial use of petroleum coking additive (PCA) - petroleum coke with a volatile matter yield of 15 to 25%, as a partial replacement for scarce coking coals in the charge in the metallurgical coke production. As a result of the review and analysis of scientific and technical literature, indicators were established that affect the formation of sintering properties of PCA and the boundary conditions for its use as part of a coal charge. It is shown that the use of petroleum coke with a volatile matter yield of less than 15% (wt.) worsens the quality of the obtained metallurgical coke, reducing its strength characteristics CSR and increasing its reactivity CRI, and the introduction into the coal charge from 5 to 50% (wt.) PCA with a content of volatile substances of 15&ndash;25% (wt.) provides an improvement in the quality of the resulting metallurgical coke. It is noted that, along with an important indicator, as the yield of volatile substances, which affects the formation of sintering properties of PCA, its group chemical composition, determined by solubility in various solvents (&alpha;-, &beta;- and &gamma;-fractions), plays an equally decisive role.The work was carried out within the framework of the State Assignment of the Ministry of&nbsp;Education and Science of the Russian Federation on NIR 0792-2020-0010 "Development of&nbsp;scientific foundations for innovative technologies for processing heavy hydrocarbon raw&nbsp;materials into environmentally friendly motor fuels and new carbon materials with controlled&nbsp;macro- and microstructural organization of the mesophase."

Analytical assessment of the behavior of biochar, as an additionally injected fuel, under conditions of blast-furnace smelting

The relevance of the issue of using carbon-neutral types of raw materials in metallurgical production is considered. One of the promising directions is the use of biomass pyrolysis product - biochar, which has a high carbon content and, as a result, a calorific value relative to biomass. A comparative analysis of the main characteristics of biochar and pulverized coal injected fuel (PCI) produced from "T" and "G" coal grades was carried out. Biochar contains less carbon and ash with a higher content of volatile substances compared to PCI. To study the combustion process of biochar in the blast furnace tuyere zone, a study of the kinetics of its combustion in a laboratory installation for the solid fuel combustion was carried out. In order to adapt the obtained biochar combustion kinetics to the conditions of the blast furnace tuyere zone, a similar study was carried out for the considered types of pulverized coal. The results of the experimental study of the combustion kinetics of the studied types of fuel are presented, according to which the fuel combustion process in front of the tuyeres consists of two phases: the first one is accompanied by a high oxygen consumption for the combustion of volatile substances; the second one is characterized by slow afterburning of the carbon residue. The longest burning time of 0.6 g fuel at a temperature of 1200 &deg;C is 762 s for T-grade PCI. Pulverized coal grade &ldquo;G&rdquo; and biochar have the similar combustion kinetics, but the latter burns faster: grade &ldquo;G&rdquo; pulverized coal burns in 369 s, and biochar in 162 s. The conclusion is made about a higher degree of biochar afterburning in the conditions of the blast furnace tuyere zone in comparison with pulverized coal fuel.

Thermogravimetric analysis of the combustion of Tuva coals before and after their carbonization

The process of combusting Tuva coals before and after their carbonization was studied using the methods of thermogravimetric analysis and electron microscopy. Coal samples were subjected to thermomechanical and elemental analysis, which revealed a higher content of volatile substances in Kaa-Khem coal (47.5 %) compared to Chadan coal (10 %). Following carbonization, a decrease in volatile substances to 11.5 % and 9.3 %, respectively, was observed. The conducted thermogravimetric analysis showed the ignition temperature of the coke residue of the Kaa-Khem and Chadan coal samples to increase by 76 °C and 90 °C, respectively, after carbonization. The burnup temperature of the coke residue after carbonizing (723 °C) Kaa-Khem coal samples remained effectively the same, while the Chadan coal showed an increase from 704 °C to 727 °C. The carbonization of coals was established to decrease the maximum reaction rate from 19 % per min to 10% per min for Kaa-Khem coal and from 26 % per min to 11 % per min for Chadan coal. The process of combusting the coke residue after coal carbonization was found to shift into the region of higher temperatures: from 448–723°C to 524–724°C for Kaa-Khem coal and from 436–704 °C to 526–727 °C for Chadan coal. A morphological analysis of the surface of coal particles after carbonization showed the appearance of larger-size pores and cracks on the surface of carbonates compared to coal before carbonization. The conclusion is made that the content of volatile substances, rather than the developed pore structure, comprises the main factor in improving the combustion characteristics of Tuva coals under the conditions of non-isothermal heating before and after their carbonization.

HYBRID ECO-FRIENDLY BIODEGRADABLE CONSTRUCTION COMPOSITES MODIFIED WITH HUMIC SUBSTANCES

Obtaining hybrid eco-friendly biodegradable structural composites was considered. The aim of this work was to determining the properties of hybrid eco-friendly biodegradable construction composites modified with humic substances. Hybrid eco-friendly construction composites were obtained on the basis of bioplastic polylactides with the addition as a filler of coffee grounds with a polyfractional composition within a particle size of 0.5 mm to 1 mm and a hybrid modifier – humic substances from brown coal. Hybrid ecofriendly construction composites were obtained by extrusion of pre-prepared raw materials in a single-screw laboratory extruder at a temperature of 170–200 °С and an auger rotation speed of 30–100 rpm. Investigated impact strength, breaking stress during bending, melt flow index (MFI) and melting temperature of hybrid ecofriendly biodegradable structural composites modified with humic substances. Optimization studies have been carried out to determine the most effective composition of new ecofriendly structural composites based on bioplastics of polylactides, coffee grounds waste and humic substances of three different types. Researching data together with the data of impact strength, allows us to make assumptions about the possibility of forming a variety of products from structurally composite material, herewith a composition with a coffee content of 50 % by mass. deserves a special attention. The data show an increase the impact strength and the breaking stress during bending a hybrid modification of ecofriendly biodegradable construction composites based on polylactide, coffee grounds waste and humic substances in 2.5 times, with optimal in terms of strength characteristics is the content of coffee grounds at 50 % wt. and 0.5 % by mass humic substances with the highest content of volatile substances and the lowest content of carbon. For such hybrid ecofriendly biodegradable construction composites based on polylactide, coffee grounds waste and humic substances, the MFI is characterized by 3.1 g/10 min. and the processing temperature range is 182–188 °C. It is shown, that the designed hybrid eco-friendly biodegradable structural composites modified with humic substances can be used in the production of high-strength structures and elements for engineering purposes.

ВПЛИВ УМОВ БІОКОНВЕРСІЇ ЗЕРНОВОЇ СИРОВИНИ НА СКЛАД ЛЕТКИХ РЕЧОВИН ДИСТИЛЯТІВ

The qualitative and quantitative composition of volatile substances of distillates obtained by bioconversion of wheat and rye under the conditions of using different enzyme preparations complexes were studied. It is shown that the content of higher alcohols in rye and wheat distillates increases by 33 and 39%, respectively, for which Laminex BG2 was additionally used as a source of cellulase, and the concentration of furfural increases by 2.2-3.5 times. The concentration of volatile substances in distillates indicates that the fungus Protease GS106 is more effective in bioconversion of both cereals than the bacterial Neutrase 1.5MG.