scholarly journals Formation mechanism of aromatics during co-pyrolysis of coal and cotton stalk

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 4449-4463
Author(s):  
Mohammad Pourjafar ◽  
Amir Khosravani ◽  
Rabi Behrooz

Pyrolysis experiments were conducted in a tubular furnace from room temperature to 600 °C at 5 °C /min, and kept for 15 min. The light tar was then derived from the liquid products of pyrolysis by n-hexane supersonic extraction. Gas chromatography–mass spectrometry was employed to analyze the light tars from cotton stalk (CS) pyrolysis, Shenmu coal (SM) pyrolysis, and co-pyrolysis of CS/SM. Microcrystalline cellulose (MCC) was selected as a model compound, and the light tar from co-pyrolysis tar of MCC/SM was investigated for comparison. The results indicated that CS improved the yields and quality of phenols and benzenes in co-pyrolysis tar and that MCC had excellent performance in the formation of mononuclear aromatics during the co-pyrolysis of MCC/SM. Based on the pyrolytic behavior of CS and SM, the mechanisms of aromatic formation were further determined. It was shown that the free radicals that cracked from CS accelerated the formation of aromatics. The alkyl and mononuclear aromatic radicals of CS pyrolysis combined with the radicals from the SM aromatic structure, which then converted to benzenes and phenols. Finally, the most favorable reaction routes of mononuclear aromatics formation were proposed.

2020 ◽  
Vol 44 (1) ◽  
Author(s):  
Hend E. Wahba ◽  
Hala S. Abd Rabbu ◽  
Mohamed E. Ibrahim

Abstract Background This study focused on the comparison of the essential oil percentage and constituents obtained from the dry seeds and the waste of coriander plant in order to reach the best ways to store the essential oil. Results The chemical composition of coriander oil was analyzed by gas chromatography–mass spectrometry (GC–MS). The analysis of coriander essential oil showed that linalool was the main constituent of dry seed oil under all conditions. It recorded 59.6, 59.28 and 47.69% of the treatments of the oil at zero time, stored in cool conditions and stored at room temperature, respectively. Concerning oil constituents of coriander waste (the remained herb after collecting seeds), the results showed that trans-anethole was the major oil constituent, followed by linalool compound. The quality of the stored oil in the refrigerator after harvest was better than the stored oil from seeds or waste under room temperature. Conclusion The changes have been observed in the chemical composition of coriander oil extracted from seed and waste subjected to different storage conditions. The waste of coriander can be considered a new source of essential oil.


BioResources ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. 1469-1481
Author(s):  
Chuyang Tang ◽  
Lei Yang ◽  
Xianchun Li ◽  
Jinling Song

Pyrolysis experiments of cotton stalk (CS) and Shenmu coal (SM) were conducted in a tubular furnace. The pyrolysis temperature was 600 °C at 5 °C/min and sustained for 15 min. The water-soluble small molecule compounds (WSMC) were derived from the liquid products obtained during pyrolysis with the methods of toluene entrainment and ultrasonic extraction. The compositions of WSMC were further characterized by gas chromatography–mass spectrometry (GC-MS). The components of the syngas were analyzed by gas chromatography (GC). The results showed that the phenol yield was promoted by the interaction of CS and SM during co-pyrolysis. Moreover, the co-pyrolysis interaction blocked the radical reaction pathway that produces amides and accelerated the formation of pyridines. Because the ester yield increased, the esterification was clearly enhanced and the yield of carboxylic acids in WSMC was reduced during co-pyrolysis. In addition, the inhibition of furan generation resulted in an increased yield of C2–C4 hydrocarbons in the co-pyrolysis syngas. The maximal yields of C2–C4 hydrocarbons all occurred at a 20/100 ratio of CS/SM. Lastly, the formation mechanisms of small molecule compounds were proposed.


Author(s):  
Nguyễn Thị Hồng Thu ◽  
Đặng Minh Nhật ◽  
Nguyễn Hoàng Dung

Sugar palm (Arenga pinnata) is a feather palm native to tropical Asia. In Vietnam, it is named Búng Báng or Đoác and grown only on the highlands in the central or northern part of Vietnam. It is utilized for many purposes, especially for Ta Vat wine production - a characteristic and unique product of Co Tu ethnic minority. However, because of the natural fermentation used in the production, the product quality is inconsistent. The purpose of this study was to examine a new procedure of using palm sap for making Ta Vat wine. Some characteristics of the sap, which was collected at Nam Giang district, Quang Nam province are determined, proving the potential of the sap for making wine product. The quality of sap changes quickly at room temperature. At low temperature (4 - 60C), the changes in sap quality are apparently slower. Examining some factors affecting its quality during the wine fermentation process, we determined the best parameters for the fermentation process as follows: inoculum size of 3% with cell density of about 1x108 cells/ml, the addition of the extract from the bark of Ceylon ironwood (Mesua ferrea L.) 4%. Keywords: Arenga pinnata, sap, Ceylon ironwood bark, Mesua ferrea L., wine fermentation.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 558
Author(s):  
Wenhui Zhu ◽  
Caiyun Zhang ◽  
Yali Chen ◽  
Qiliang Deng

Photothermal materials are attracting more and more attention. In this research, we synthesized a ferrocene-containing polymer with magnetism and photothermal properties. The resulting polymer was characterized by Fourier-transform infrared (FT-IR), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Its photo-thermocatalytic activity was investigated by choosing methylene blue (MB) as a model compound. The degradation percent of MB under an irradiated 808 nm laser reaches 99.5% within 15 min, and the degradation rate is 0.5517 min−1, which is 145 times more than that of room temperature degradation. Under irradiation with simulated sunlight, the degradation rate is 0.0092 min−1, which is approximately 2.5 times more than that of room temperature degradation. The present study may open up a feasible route to degrade organic pollutants.


Transfusion ◽  
2021 ◽  
Vol 61 (S1) ◽  
Author(s):  
Turid Helen Felli Lunde ◽  
Lindsay Hartson ◽  
Shawn Lawrence Bailey ◽  
Tor Audun Hervig
Keyword(s):  

2011 ◽  
Vol 78 (4) ◽  
pp. 385-390 ◽  
Author(s):  
Priscilla A Melville ◽  
Nilson R Benites ◽  
Monica Ruz-Peres ◽  
Eugenio Yokoya

The presence of yeasts in milk may cause physical and chemical changes limiting the durability and compromising the quality of the product. Moreover, milk and dairy products contaminated by yeasts may be a potential means of transmission of these microorganisms to man and animals causing several kinds of infections. This study aimed to determine whether different species of yeasts isolated from bovine raw milk had the ability to develop at 37°C and/or under refrigeration temperature. Proteinase and phospholipase activities resulting from these yeasts were also monitored at different temperatures. Five genera of yeasts (Aureobasidium sp., Candida spp., Geotrichum spp., Trichosporon spp. and Rhodotorula spp.) isolated from bovine raw milk samples were evaluated. All strains showed one or a combination of characteristics: growth at 37°C (99·09% of the strains), psychrotrophic behaviour (50·9%), proteinase production (16·81% of the strains at 37°C and 4·09% under refrigeration) and phospholipase production (36·36% of the isolates at 37°C and 10·9% under refrigeration), and all these factors may compromise the quality of the product. Proteinase production was similar for strains incubated at 37°C (16·81% of the isolates) and room temperature (17·27%) but there was less amount of phospholipase-producing strains at room temperature (15·45% of the isolates were positive) when compared with incubation at 37°C (36·36%). Enzymes production at 37°C by yeasts isolated from milk confirmed their pathogenic potential. The refrigeration temperature was found to be most efficient to inhibit enzymes production and consequently ensure better quality of milk. The viability of yeasts and the activity of their enzymes at different temperatures are worrying because this can compromise the quality of dairy products at all stages of production and/or storage, and represent a risk to the consumer.


2021 ◽  
Vol 11 ◽  
pp. 184798042098153
Author(s):  
Norsahika Mohd Basir ◽  
Norkhalizatul Akmal Mohd Jamil ◽  
Halimaton Hamdan

The catalytic conversion of palm oil was carried out over four zeolite catalysts—Y, ZSM-5, Y-ZSM-5 hybrid, and Y/ZSM-5 composite—to produce jet biofuel with high amount of alkanes and low amount of aromatic hydrocarbons. The zeolite Y-ZSM-5 hybrid catalyst was synthesized using crystalline zeolite Y as the seed for the growth of zeolite ZSM-5. Synthesized zeolite catalysts were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, and temperature programmed desorption of ammonia, while the chemical compositions of the jet biofuel were analyzed by gas chromatography-mass spectrometry (GC-MS). The conversion of palm oil over zeolite Y resulted in the highest yield (42 wt%) of jet biofuel: a high selectivity of jet range alkanes (51%) and a low selectivity of jet range aromatic hydrocarbons (25%). Zeolite Y-ZSM-5 hybrid catalyst produced a decreased percentage of jet range alkane (30%) and a significant increase in the selectivity of aromatic hydrocarbons (57%). The highest conversion of palm oil to hydrocarbon compounds was achieved by zeolite Y-ZSM-5 hybrid catalyst (99%), followed by zeolite Y/ZSM-5 composite (96%), zeolite Y (91%), and zeolite ZSM-5 (74%). The reaction routes for converting palm oil to jet biofuel involve deoxygenation of fatty acids into C15–C18 alkanes via decarboxylation and decarbonylation, catalytic cracking into C8–C14 alkanes, and cycloalkanes as well as aromatization into aromatic hydrocarbon.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hala Messai ◽  
Salim Meziani ◽  
Athmane Fouathia

Purpose The purpose of this paper is to highlight the performance of the Chaboche model in relation to the database identification, tests with imposed deformations were conducted at room temperature on 304L stainless steel specimens. Design/methodology/approach The first two tests were performed in tension-compression between ±0.005 and ±0.01; in the third test, each cycle is composed of the combination of a compression tensile cycle between ±0.01 followed by a torsion cycle between ±0.01723 (non-proportional path), and the last, uniaxial ratcheting test with a mean stress between 250 MPa and −150 MPa. Several identifications of a Chaboche-type model were then performed by considering databases composed of one or more of the cited tests. On the basis of these identifications, the simulations of a large number of ratchet tests in particular were carried out. Findings The results present the effect of the optimized parameters on the prediction of the behavior of materials which is reported in the graphs, Optimizations 1 and 2 of first and second tests and Optimization 4 of the third test giving a good prediction of the increasing/decreasing pre-deformation amplitude. Originality/value The quality of the model's predictions strongly depends on the richness of the database used for the identification of the parameters.


2021 ◽  
pp. 18-19
Author(s):  
Twamoghna De ◽  
Purushottam Kumar ◽  
Jayati Pal

The study was done to formulate a drink from an old medicinal herb and retain all the potential benets with a new taste and avor. For this an herbal drink was formulated and its quality ascertained. In the rst part of the study, syrup was prepared from the raw leaves of the herb with addition of acids and avors. Then this syrup was diluted further followed by carbonation with 1:3 ratio of soda water and bottled. Three samples were prepared namely, T1 (same as previous but with 1:3 ratio carbonation and dividing the sample hot lled and cold lled ). In the next part, prepared samples were subjected to sensory evaluation,chemical and microbial analysis when fresh and 0 after regular intervals at room temperature (27±1 °C) and refrigerated temperature (below 7 C). Microbial analysis of the product was done to check the quality of the herbal drink and self-life of the product. The control sample T1 cold lled was the most acceptable due to its unique taste and avor, followed by sample T1( hot lled) . The present study entailed to conclude that preparation of a drink with B. monnieri leaf extracts gives a new taste and avor with high nutritional values. This drink can be stored safe for nearly a month if carbonated and storage at refrigerated 0 temperature (below 5 C).


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