Pub Date : 2023-10-11DOI: 10.1080/07373937.2023.2261049
Juan Rodríguez-Ramírez, Milad Farzad, Zahra Noori O’Connor, Jamal Yagoobi
AbstractThis study evaluates the heat and mass transfer behavior of innovative Radial Jet Reattachment (RJR) nozzles to analyze the texture and color characteristics of crispy tostadas. A new experimental method for measuring steady-state evaporation is proposed and validated to determine the averaged coefficients of convective heat and mass transfer for different drying conditions and geometrical parameters of RJR nozzles. The experiment is designed using a 24 factorial design approach. The factors that are considered include nozzle exit angle (10° and 45°), tortillas thicknesses (1.03 mm and 1.66 mm), air drying temperature (200 °C and 250 °C) and air mass flow rate (17.0 m3/h and 27.2 m3/h). The findings indicate that for the impingement drying of tortillas, it is crucial to consider convection and diffusion as the primary factors in selecting the appropriate operating conditions. Moreover, the study concludes that the RJR nozzle with a 45° exit angle exhibits a higher drying rate than the RJR nozzle with a 10° exit angle. The study found that neither the type of nozzle nor the air drying conditions had a significant impact (α ≤ 0.05) on the texture and color of the final product. The utilization of RJR nozzles for impinging drying of tortillas is a promising and robust process that enables the production of crispy tostadas without negatively impacting the quality characteristics of the final product.Keywords: Impingement dryinginnovative nozzlesheat and mass transferfood qualityRJR nozzle Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis study was supported by the Center for Advanced Research in Drying (CARD), a National Science Foundation Industry-University Cooperative Research Center located at Worcester Polytechnic Institute. The Rodríguez-Ramírez J. author acknowledges CONACyT of Mexico for the international scholar fellowship.
{"title":"Radial Jet Reattachment impingement drying of corn tortillas","authors":"Juan Rodríguez-Ramírez, Milad Farzad, Zahra Noori O’Connor, Jamal Yagoobi","doi":"10.1080/07373937.2023.2261049","DOIUrl":"https://doi.org/10.1080/07373937.2023.2261049","url":null,"abstract":"AbstractThis study evaluates the heat and mass transfer behavior of innovative Radial Jet Reattachment (RJR) nozzles to analyze the texture and color characteristics of crispy tostadas. A new experimental method for measuring steady-state evaporation is proposed and validated to determine the averaged coefficients of convective heat and mass transfer for different drying conditions and geometrical parameters of RJR nozzles. The experiment is designed using a 24 factorial design approach. The factors that are considered include nozzle exit angle (10° and 45°), tortillas thicknesses (1.03 mm and 1.66 mm), air drying temperature (200 °C and 250 °C) and air mass flow rate (17.0 m3/h and 27.2 m3/h). The findings indicate that for the impingement drying of tortillas, it is crucial to consider convection and diffusion as the primary factors in selecting the appropriate operating conditions. Moreover, the study concludes that the RJR nozzle with a 45° exit angle exhibits a higher drying rate than the RJR nozzle with a 10° exit angle. The study found that neither the type of nozzle nor the air drying conditions had a significant impact (α ≤ 0.05) on the texture and color of the final product. The utilization of RJR nozzles for impinging drying of tortillas is a promising and robust process that enables the production of crispy tostadas without negatively impacting the quality characteristics of the final product.Keywords: Impingement dryinginnovative nozzlesheat and mass transferfood qualityRJR nozzle Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis study was supported by the Center for Advanced Research in Drying (CARD), a National Science Foundation Industry-University Cooperative Research Center located at Worcester Polytechnic Institute. The Rodríguez-Ramírez J. author acknowledges CONACyT of Mexico for the international scholar fellowship.","PeriodicalId":11374,"journal":{"name":"Drying Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136063045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AbstractThe study explored using a hot-air oven at various temperatures (35, 45, and 55 °C) as a promising alternative to traditional sun-drying for salted shrimp paste production. Comparing drying profiles, fermentation rate, quality, and acceptability with conventional sun-drying (CON), it was found that the alternative hot-air oven led to lower enzymatic activities and degree of hydrolysis during a 30-day fermentation (p < 0.05). Consequently, the alternative samples exhibited lower development of distinctive characteristics (color, browning intensity, formal, ammonia, nitrogen contents, and antioxidant capabilities) resulting in lower sensory scores compared to CON (p < 0.05). Interestingly, microbial populations in hot-air-dried samples were also lower than CON (p < 0.05). Based on PCA biplots and drying duration, drying at 45 °C with a hot-air oven seemed optimal for shrimp paste production. However, adjustments, such as prolonging fermentation or using a starter culture, are needed to make the alternative process comparable to the traditional product.Keywords: Shrimp pastehot-air ovendrying processfermentation ratefermented shrimp Data availability statementThe data that supports the findings of this study are available from the corresponding author upon reasonable request.Ethical statementThe author obtained a certificate of ‘Basic Human Subject Protection Course’ (NU-NU042), which is available for preliminary experiments with sensory evaluations. The participants provided their informed consent to participate in this study.Disclosure statementNo potential competing interest was reported by the authors.Additional informationFundingThis research was funded by the National Research Council of Thailand (NRCT, Research Grants for Talented Young Researchers (2021), grant no. N41A640118).
{"title":"The use of hot-air oven as an alternative drying method for salted shrimp paste production: Drying profile, fermentation rate, quality, and acceptability","authors":"Jaksuma Pongsetkul, Soottawat Benjakul, Pakpoom Boonchuen","doi":"10.1080/07373937.2023.2267665","DOIUrl":"https://doi.org/10.1080/07373937.2023.2267665","url":null,"abstract":"AbstractThe study explored using a hot-air oven at various temperatures (35, 45, and 55 °C) as a promising alternative to traditional sun-drying for salted shrimp paste production. Comparing drying profiles, fermentation rate, quality, and acceptability with conventional sun-drying (CON), it was found that the alternative hot-air oven led to lower enzymatic activities and degree of hydrolysis during a 30-day fermentation (p < 0.05). Consequently, the alternative samples exhibited lower development of distinctive characteristics (color, browning intensity, formal, ammonia, nitrogen contents, and antioxidant capabilities) resulting in lower sensory scores compared to CON (p < 0.05). Interestingly, microbial populations in hot-air-dried samples were also lower than CON (p < 0.05). Based on PCA biplots and drying duration, drying at 45 °C with a hot-air oven seemed optimal for shrimp paste production. However, adjustments, such as prolonging fermentation or using a starter culture, are needed to make the alternative process comparable to the traditional product.Keywords: Shrimp pastehot-air ovendrying processfermentation ratefermented shrimp Data availability statementThe data that supports the findings of this study are available from the corresponding author upon reasonable request.Ethical statementThe author obtained a certificate of ‘Basic Human Subject Protection Course’ (NU-NU042), which is available for preliminary experiments with sensory evaluations. The participants provided their informed consent to participate in this study.Disclosure statementNo potential competing interest was reported by the authors.Additional informationFundingThis research was funded by the National Research Council of Thailand (NRCT, Research Grants for Talented Young Researchers (2021), grant no. N41A640118).","PeriodicalId":11374,"journal":{"name":"Drying Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135094060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-09DOI: 10.1080/07373937.2023.2260867
Tobias Nienke, Juan Sebastian Gomez Bonilla, Arno Kwade, Daniel Eggerath
AbstractPrecise coating processes demand sensitive drying processes. The present work investigates the operation of hybrid convective drying nozzles for combining impingement nozzles with impingement-free nozzles. Impingement-free nozzles show good uniformity, whereas impingement nozzles are characterized by higher heat transfer but greater non-uniformity across the pitch. Volumetric flow ratio between the nozzle types, lateral distance, substrate distance and angle of impingement are the parameters of this study. Compared with purely impingement-free nozzles, the combination can achieve increased heat transfer with moderate losses in distribution uniformity. A divergent impingement jet with a small lateral distance and a small substrate distance proves to be advantageous. In addition, a consideration of energy requirements shows that impingement-free nozzles, due to their lower resistance, can deliver the same volume flow rates with lower blower power. As a result, the reduction of the impingement component in the hybrid nozzle is advantageous in terms of energy.Keywords: CoatingRoll2Rolldrying nozzleheat transfer Disclosure statementNo potential competing interest was reported by the authors.Table 1. Outlet velocity and Reynolds numbers for different volumetric flow ratios and nozzle types.Display TableTable 2. Coefficient of variation for different impingement angles.Download CSVDisplay Table
{"title":"Combination of different nozzle concepts for simultaneous optimization of heat transfer and its uniform distribution in convection drying applications","authors":"Tobias Nienke, Juan Sebastian Gomez Bonilla, Arno Kwade, Daniel Eggerath","doi":"10.1080/07373937.2023.2260867","DOIUrl":"https://doi.org/10.1080/07373937.2023.2260867","url":null,"abstract":"AbstractPrecise coating processes demand sensitive drying processes. The present work investigates the operation of hybrid convective drying nozzles for combining impingement nozzles with impingement-free nozzles. Impingement-free nozzles show good uniformity, whereas impingement nozzles are characterized by higher heat transfer but greater non-uniformity across the pitch. Volumetric flow ratio between the nozzle types, lateral distance, substrate distance and angle of impingement are the parameters of this study. Compared with purely impingement-free nozzles, the combination can achieve increased heat transfer with moderate losses in distribution uniformity. A divergent impingement jet with a small lateral distance and a small substrate distance proves to be advantageous. In addition, a consideration of energy requirements shows that impingement-free nozzles, due to their lower resistance, can deliver the same volume flow rates with lower blower power. As a result, the reduction of the impingement component in the hybrid nozzle is advantageous in terms of energy.Keywords: CoatingRoll2Rolldrying nozzleheat transfer Disclosure statementNo potential competing interest was reported by the authors.Table 1. Outlet velocity and Reynolds numbers for different volumetric flow ratios and nozzle types.Display TableTable 2. Coefficient of variation for different impingement angles.Download CSVDisplay Table","PeriodicalId":11374,"journal":{"name":"Drying Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135141370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-04DOI: 10.1080/07373937.2023.2261047
Mariia Sobulska
AbstractIn the frame of this work, the experimental analysis of the reconstitution properties, sorption isotherms and the Fourier-transform infrared spectroscopy (FTIR) spectra of maltodextrin powder was carried out. Before the analysis the substance was dried by standard spray drying method or flame spray drying (FSD). During the analyses, the influence of the applied FSD parameters on the analyzed properties was also estimated. The powders dried using the standard spray dryer were characterized by a better wettability parameter, which was related to a high bulk density. A shorter solubility time was obtained for powders dried by the FSD method, which may be explained by the larger particle diameters. Analyzing maltodextrin powders dried with the FSD, a significant influence of the atomization pressure and particle size on the wettability parameter was found. Application of FSD method does not affect the sorption characteristics of maltodextrin and does not change significantly the chemical structure of the material, since characteristic peaks of FTIR spectra were preserved after the FSD.Keywords: Flame spray dryingsorption isothermsFTIRwettabilitysolubility time AcknowledgementsThe author is grateful to Dr Marcin Piatkowski for help in carrying out the drying tests, Dr Aleksandra Kedzierska-Sar for help with DVS analysis and to mgr Michal Krempski-Smejda for help with FTIR spectroscopy.Disclosure statementNo potential conflict of interest was reported by the authors.
{"title":"Flame spray drying of maltodextrin","authors":"Mariia Sobulska","doi":"10.1080/07373937.2023.2261047","DOIUrl":"https://doi.org/10.1080/07373937.2023.2261047","url":null,"abstract":"AbstractIn the frame of this work, the experimental analysis of the reconstitution properties, sorption isotherms and the Fourier-transform infrared spectroscopy (FTIR) spectra of maltodextrin powder was carried out. Before the analysis the substance was dried by standard spray drying method or flame spray drying (FSD). During the analyses, the influence of the applied FSD parameters on the analyzed properties was also estimated. The powders dried using the standard spray dryer were characterized by a better wettability parameter, which was related to a high bulk density. A shorter solubility time was obtained for powders dried by the FSD method, which may be explained by the larger particle diameters. Analyzing maltodextrin powders dried with the FSD, a significant influence of the atomization pressure and particle size on the wettability parameter was found. Application of FSD method does not affect the sorption characteristics of maltodextrin and does not change significantly the chemical structure of the material, since characteristic peaks of FTIR spectra were preserved after the FSD.Keywords: Flame spray dryingsorption isothermsFTIRwettabilitysolubility time AcknowledgementsThe author is grateful to Dr Marcin Piatkowski for help in carrying out the drying tests, Dr Aleksandra Kedzierska-Sar for help with DVS analysis and to mgr Michal Krempski-Smejda for help with FTIR spectroscopy.Disclosure statementNo potential conflict of interest was reported by the authors.","PeriodicalId":11374,"journal":{"name":"Drying Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135591017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AbstractThe volume of sewage sludge generated continues to increase, leading to harmful secondary pollution and highlighting the pressing need for sewage sludge reduction. Sewage sludge drying is a well-established method for treating municipal sewage sludge. This study systematically reviews the latest research on the formation and control of gaseous pollutants during sewage sludge thermal drying. First, this paper comprehensively introduces sewage sludge drying, covering its principles, heat sources, and the inevitable generation of waste gas during the drying process of sewage sludge rich in organic matter. Subsequently, it summarizes the methods for detecting sewage sludge drying exhaust gas and outlines the emission characteristics of such exhaust gas. The three main types of dry exhaust gases discussed include volatile nitrogen-containing compounds, represented by ammonia (NH3); volatile sulfur-containing compounds, represented by hydrogen sulfide (H2S); and the benzene series (BTEX). Finally, based on current technical capabilities, this paper proposes two methods for controlling pollution from sewage sludge drying exhaust gas: suppressing pollutant release during the drying process and treating exhaust gas at the end of drying. Inhibition of pollutant release during the drying process primarily involves reducing the types and quantities of pollutants released by adjusting the sewage sludge drying temperature and time, employing sewage sludge conditioning, and implementing others. Drying back-end exhaust gas treatment removes contaminants from the drying exhaust gas through processes like condensation, adsorption, absorption, biodegradation and other methods. This work offers a fresh perspective on understanding how various factors in the sewage sludge drying process influence the characteristics of dried exhaust gas emissions and the overall control of sewage sludge exhaust gas emissions.Keywords: Sewage sludge dryingdry exhaust gasemission characteristicspollution control Disclosure statementNo potential conflict of interest was reported by the authors.Additional informationFundingThis research was funded by the Fundamental Research Funds for the Central Universities (FRF-TP-20-010A2) and the Self-directed Project of State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing (41622202).
{"title":"Research progress on exhaust gas emissions and control technology during sewage sludge thermal drying: A review","authors":"Wei Ling, Yi Xing, Chengwang Zhao, Chen Hong, Weibo Feng, Yijie Wang, Jiashuo Hu, Jiachen Hou, Lihui Feng","doi":"10.1080/07373937.2023.2260895","DOIUrl":"https://doi.org/10.1080/07373937.2023.2260895","url":null,"abstract":"AbstractThe volume of sewage sludge generated continues to increase, leading to harmful secondary pollution and highlighting the pressing need for sewage sludge reduction. Sewage sludge drying is a well-established method for treating municipal sewage sludge. This study systematically reviews the latest research on the formation and control of gaseous pollutants during sewage sludge thermal drying. First, this paper comprehensively introduces sewage sludge drying, covering its principles, heat sources, and the inevitable generation of waste gas during the drying process of sewage sludge rich in organic matter. Subsequently, it summarizes the methods for detecting sewage sludge drying exhaust gas and outlines the emission characteristics of such exhaust gas. The three main types of dry exhaust gases discussed include volatile nitrogen-containing compounds, represented by ammonia (NH3); volatile sulfur-containing compounds, represented by hydrogen sulfide (H2S); and the benzene series (BTEX). Finally, based on current technical capabilities, this paper proposes two methods for controlling pollution from sewage sludge drying exhaust gas: suppressing pollutant release during the drying process and treating exhaust gas at the end of drying. Inhibition of pollutant release during the drying process primarily involves reducing the types and quantities of pollutants released by adjusting the sewage sludge drying temperature and time, employing sewage sludge conditioning, and implementing others. Drying back-end exhaust gas treatment removes contaminants from the drying exhaust gas through processes like condensation, adsorption, absorption, biodegradation and other methods. This work offers a fresh perspective on understanding how various factors in the sewage sludge drying process influence the characteristics of dried exhaust gas emissions and the overall control of sewage sludge exhaust gas emissions.Keywords: Sewage sludge dryingdry exhaust gasemission characteristicspollution control Disclosure statementNo potential conflict of interest was reported by the authors.Additional informationFundingThis research was funded by the Fundamental Research Funds for the Central Universities (FRF-TP-20-010A2) and the Self-directed Project of State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing (41622202).","PeriodicalId":11374,"journal":{"name":"Drying Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135829662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AbstractA fast, simple and cost-effective technique has been used to produce spray-drying porous particles of salbutamol sulfate (SS) for inhalation drug delivery. The particles were produced using water as solvent and ammonium bicarbonate as pore-forming agent. A full factorial experimental design (24) with a central point was used to evaluate the influence of process parameters (drying air inlet temperature, atomization air volume flowrate, feed volume flowrate and the pore-forming agent concentration) on process yield, moisture content, densities and particle size. In addition, particle morphology, in-vitro aerosolization properties, stability and cytotoxicity of selected samples were studied. Within the experimental design parameters window, it was shown that the highest inlet temperature and pore-forming agent concentration were the factors that more affected the process yield and tap density values. Particles with the lowest tap densities values exhibited porous morphology. In addition, the pore-forming agent concentration proved to be the most significant variable affecting particle size. The highest pore-forming agent concentration, the largest particle size. The porous particles exhibit remarkable aerosolization performance, surpassing the performance of previously reported SS porous particles and a commercial formulation. These powders showed a high process yield and the absence of ammonium bicarbonate in the final product, as confirmed by FT-IR. Furthermore, the powders presented good stability even over long periods of time and did not exhibit cytotoxicity on the murine alveolar macrophage cell line RAW 264.7.Keywords: Porous particlessalbutamol sulfatespray dryingammonium bicarbonate Disclosure statementThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.Additional informationFundingThe authors thank the financial support from Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) [grant number: PIP 11220150100704CO] and Universidad Nacional del Sur (UNS) of Argentina [grant number: PGI 24M/163].
{"title":"Advancements in salbutamol sulphate formulation: Spray-drying technique for the production of porous particles with enhanced properties for inhalation drug delivery","authors":"Marcos Andrés Serain, Ana Carla Castro-Guijarro, Marina Inés Flamini, Verónica Bucalá, Loreana Carolina Gallo","doi":"10.1080/07373937.2023.2262017","DOIUrl":"https://doi.org/10.1080/07373937.2023.2262017","url":null,"abstract":"AbstractA fast, simple and cost-effective technique has been used to produce spray-drying porous particles of salbutamol sulfate (SS) for inhalation drug delivery. The particles were produced using water as solvent and ammonium bicarbonate as pore-forming agent. A full factorial experimental design (24) with a central point was used to evaluate the influence of process parameters (drying air inlet temperature, atomization air volume flowrate, feed volume flowrate and the pore-forming agent concentration) on process yield, moisture content, densities and particle size. In addition, particle morphology, in-vitro aerosolization properties, stability and cytotoxicity of selected samples were studied. Within the experimental design parameters window, it was shown that the highest inlet temperature and pore-forming agent concentration were the factors that more affected the process yield and tap density values. Particles with the lowest tap densities values exhibited porous morphology. In addition, the pore-forming agent concentration proved to be the most significant variable affecting particle size. The highest pore-forming agent concentration, the largest particle size. The porous particles exhibit remarkable aerosolization performance, surpassing the performance of previously reported SS porous particles and a commercial formulation. These powders showed a high process yield and the absence of ammonium bicarbonate in the final product, as confirmed by FT-IR. Furthermore, the powders presented good stability even over long periods of time and did not exhibit cytotoxicity on the murine alveolar macrophage cell line RAW 264.7.Keywords: Porous particlessalbutamol sulfatespray dryingammonium bicarbonate Disclosure statementThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.Additional informationFundingThe authors thank the financial support from Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) [grant number: PIP 11220150100704CO] and Universidad Nacional del Sur (UNS) of Argentina [grant number: PGI 24M/163].","PeriodicalId":11374,"journal":{"name":"Drying Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135243463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-27DOI: 10.1080/07373937.2023.2259974
Lovrenc Novak, Brane Širok, Mojca Zupanc, Marko Hočevar
Convective sewage sludge drying is often carried out in belt dryers, where the air flow is directed through the layer. In such a configuration, drying air properties, as well as the structure of the layer and its homogeneity are key factors affecting the drying process. In the present work, these factors were investigated using laboratory experiments on relatively large sludge samples with a mass of several kilograms. Drying was performed at relatively low drying air parameters (time-averaged temperatures of 65 to 80 °C and velocities of 0.44 to 0.78 m/s). The inhomogeneity of the sludge layer drying was observed by measuring the layer surface temperature with an IR camera. The reduction in layer thickness during drying was measured using an optical laser-based method. Analysis of the data included regression and fitting of the data to parametric drying curves, with the modified Nadhari drying law providing the best fit. The standard deviation of the layer surface thermograms (S) was used as a parameter that accounted for the layer homogeneity and consequently drying evenness. Higher values of S corresponded to lower drying rates and consequently longer drying times, highlighting the importance of producing layers with a homogenous structure. The measured layer thickness reduction rate indicated the overall drying intensity almost from the beginning of drying. Both the surface temperature unevenness and the layer height reduction measurement methods were demonstrated as viable approaches for real-time monitoring of the drying process with potential for application in real-scale dryers.
{"title":"Effects of layer inhomogeneities on the process of sewage sludge convective drying","authors":"Lovrenc Novak, Brane Širok, Mojca Zupanc, Marko Hočevar","doi":"10.1080/07373937.2023.2259974","DOIUrl":"https://doi.org/10.1080/07373937.2023.2259974","url":null,"abstract":"Convective sewage sludge drying is often carried out in belt dryers, where the air flow is directed through the layer. In such a configuration, drying air properties, as well as the structure of the layer and its homogeneity are key factors affecting the drying process. In the present work, these factors were investigated using laboratory experiments on relatively large sludge samples with a mass of several kilograms. Drying was performed at relatively low drying air parameters (time-averaged temperatures of 65 to 80 °C and velocities of 0.44 to 0.78 m/s). The inhomogeneity of the sludge layer drying was observed by measuring the layer surface temperature with an IR camera. The reduction in layer thickness during drying was measured using an optical laser-based method. Analysis of the data included regression and fitting of the data to parametric drying curves, with the modified Nadhari drying law providing the best fit. The standard deviation of the layer surface thermograms (S) was used as a parameter that accounted for the layer homogeneity and consequently drying evenness. Higher values of S corresponded to lower drying rates and consequently longer drying times, highlighting the importance of producing layers with a homogenous structure. The measured layer thickness reduction rate indicated the overall drying intensity almost from the beginning of drying. Both the surface temperature unevenness and the layer height reduction measurement methods were demonstrated as viable approaches for real-time monitoring of the drying process with potential for application in real-scale dryers.","PeriodicalId":11374,"journal":{"name":"Drying Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135580062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The generation of internal stress (IS) in flat-sawn and quarter-sawn rubberwood boards during drying has been investigated using an online restoring force (RF) technique, which restrained a half-split rectangular wood specimen. Particular attention was given to the longest IS reversal regime. The IS development proceeds faster in the flat-sawn specimens than that in the quarter-sawn specimens while the maximum IS magnitudes in both specimens are rather similar. By normalizing the IS reversal period, a master IS profile, the derivative of the measured RF to the IS reversal time ratio versus the IS reversal time ratio, is proposed. This master curve, exhibiting some degree of independence from wood orientation and drying temperature, shows variations correlated with the free water content in the wet zone and the dry/wet zone fractions. The process of IS reversal, unaffected by temporary unrestraint, advances as the dry zone expands inwards and ends when the wet zone disappears. Assuming mechanical equilibrium between the dry and wet zones, the IS in both zones can be estimated from the RF data. The maximum tensile IS in the dry zone, indicating a risk of surface checks, evolves at slightly lower magnitudes at higher drying temperatures and is lower in the quarter-sawn specimens. The IS relaxation in the dry zone, still largely taking place in the absence of the applied RF, highlights the main contribution of the dry/wet zone fractions, continuing to proceed without restraining, to the IS development. These findings, emphasizing the significance of dry and wet zones, should pave the way for a better understanding of the IS development within wood during drying.
{"title":"Internal stress development within wood during drying: A master curve concept and its application on drying stress evaluation","authors":"Kuntida Srisuchart, Jaipet Tomad, Satjapan Leelatanon, Sataporn Jantawee, Nirundorn Matan","doi":"10.1080/07373937.2023.2259467","DOIUrl":"https://doi.org/10.1080/07373937.2023.2259467","url":null,"abstract":"Abstract The generation of internal stress (IS) in flat-sawn and quarter-sawn rubberwood boards during drying has been investigated using an online restoring force (RF) technique, which restrained a half-split rectangular wood specimen. Particular attention was given to the longest IS reversal regime. The IS development proceeds faster in the flat-sawn specimens than that in the quarter-sawn specimens while the maximum IS magnitudes in both specimens are rather similar. By normalizing the IS reversal period, a master IS profile, the derivative of the measured RF to the IS reversal time ratio versus the IS reversal time ratio, is proposed. This master curve, exhibiting some degree of independence from wood orientation and drying temperature, shows variations correlated with the free water content in the wet zone and the dry/wet zone fractions. The process of IS reversal, unaffected by temporary unrestraint, advances as the dry zone expands inwards and ends when the wet zone disappears. Assuming mechanical equilibrium between the dry and wet zones, the IS in both zones can be estimated from the RF data. The maximum tensile IS in the dry zone, indicating a risk of surface checks, evolves at slightly lower magnitudes at higher drying temperatures and is lower in the quarter-sawn specimens. The IS relaxation in the dry zone, still largely taking place in the absence of the applied RF, highlights the main contribution of the dry/wet zone fractions, continuing to proceed without restraining, to the IS development. These findings, emphasizing the significance of dry and wet zones, should pave the way for a better understanding of the IS development within wood during drying.","PeriodicalId":11374,"journal":{"name":"Drying Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135860701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-22DOI: 10.1080/07373937.2023.2258980
Lei Zhang, Ao Zhang, Shanshan Zhou, Qianqian Wang, Zhenyuan Hu, Chenglin Li, Yang Hu, Haile Ma, Cunshan Zhou
AbstractDecolorization is a necessary step before the extraction of okra pectin, and the reapplication of removed pigment will benefit hierarchical utilization of resources. Based on sweeping-frequency ultrasonic preprocessing (SFUP), effects of drying methods (hot air drying (HD), freeze-drying (FD)), sieves (of 60, 80, and 120 mesh) on removal rate and stability of okra pigment (OPI) were investigated. Color deepening caused by the formation of enzymatic products within 1 h of OPI degradation was explained. The extracted OPI was finally applied to noodles to check its stability further. Results showed that compared with non-ultrasonic treatment, SFUP increased removal rate of OPI with the maximum value of 49.32%, and further enhanced the stability of OPI when applied to noodles. OPI through sieves of 80 mesh owned brighter color and more excellent stability, and colored noodles with OPI through SFUP and FD had a small total color difference and strong stability.Keywords: Sweeping-frequency ultrasonic preprocessingdrying methodsifted okra powderpigment Ethical statementThe research does not involve animals or Humans, sensory evaluation and/or customer testing. Informed consent was obtained from all individual participants included in the study.Disclosure statementNo potential conflict of interest was reported by the authors.Author contributionsLei Zhang: Data curation, Writing-original draft, Funding acquisition. Ao Zhang, Shanshan Zhou, Qianqian Wang, Zhenyuan Hu, Chenglin Li and Yang Hu: Investigation, Data curation, Writing-original draft. Haile Ma and Cunshan Zhou: Supervision.Data availability statementThe data that support the findings of this study are available upon reasonable request.Additional informationFundingThis work was supported by the National Natural Science Foundation of China (31801599); Scientific Research Project of College Students of Jiangsu University (21A299, J21AE0134); Innovation Training Program for College Students of Jiangsu University (202110299889X). Heartfelt thanks also should be expressed to Wahia Hafida and Xue Wang for supporting this work.
{"title":"Sweeping-frequency ultrasonic preprocessing improves removal rate and stability of pigment removed from okra powders by different drying and sieving methods","authors":"Lei Zhang, Ao Zhang, Shanshan Zhou, Qianqian Wang, Zhenyuan Hu, Chenglin Li, Yang Hu, Haile Ma, Cunshan Zhou","doi":"10.1080/07373937.2023.2258980","DOIUrl":"https://doi.org/10.1080/07373937.2023.2258980","url":null,"abstract":"AbstractDecolorization is a necessary step before the extraction of okra pectin, and the reapplication of removed pigment will benefit hierarchical utilization of resources. Based on sweeping-frequency ultrasonic preprocessing (SFUP), effects of drying methods (hot air drying (HD), freeze-drying (FD)), sieves (of 60, 80, and 120 mesh) on removal rate and stability of okra pigment (OPI) were investigated. Color deepening caused by the formation of enzymatic products within 1 h of OPI degradation was explained. The extracted OPI was finally applied to noodles to check its stability further. Results showed that compared with non-ultrasonic treatment, SFUP increased removal rate of OPI with the maximum value of 49.32%, and further enhanced the stability of OPI when applied to noodles. OPI through sieves of 80 mesh owned brighter color and more excellent stability, and colored noodles with OPI through SFUP and FD had a small total color difference and strong stability.Keywords: Sweeping-frequency ultrasonic preprocessingdrying methodsifted okra powderpigment Ethical statementThe research does not involve animals or Humans, sensory evaluation and/or customer testing. Informed consent was obtained from all individual participants included in the study.Disclosure statementNo potential conflict of interest was reported by the authors.Author contributionsLei Zhang: Data curation, Writing-original draft, Funding acquisition. Ao Zhang, Shanshan Zhou, Qianqian Wang, Zhenyuan Hu, Chenglin Li and Yang Hu: Investigation, Data curation, Writing-original draft. Haile Ma and Cunshan Zhou: Supervision.Data availability statementThe data that support the findings of this study are available upon reasonable request.Additional informationFundingThis work was supported by the National Natural Science Foundation of China (31801599); Scientific Research Project of College Students of Jiangsu University (21A299, J21AE0134); Innovation Training Program for College Students of Jiangsu University (202110299889X). Heartfelt thanks also should be expressed to Wahia Hafida and Xue Wang for supporting this work.","PeriodicalId":11374,"journal":{"name":"Drying Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136058827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The majority of the rural areas in developing countries are not connected to the electric grid. Rice production produces a significant amount of rice husk as a byproduct/waste but this waste can be used as a source of energy for drying of the rough rice. The aim of this research was to evaluate the performance and improve the design and operation of a rice husk fueled mixed flow grain dryer for small scale rural farmers using a validated 3-D computational fluid dynamics (CFD) model. The model was applied to predict the airflow and heat and mass transfer characteristics of the designed prototype rough rice dryer. The model took into account the geometrical detail of the dryer assembly, the relevant boundary and initial conditions, and model input parameters. The results identified relatively stagnant regions at the top and the side walls of the dryer. The observed relatively high variation in drying air velocity distribution caused a relatively high variation in drying characteristics of the rice grain. The model was applied to modify the design and operation procedure of the dryer to improve the performance in terms of drying uniformity and drying time. After 2 h drying time, the difference between the maximum and minimum moisture content values for the original and modified design was 12.9% and 8.5%, respectively. There was an exponential relationship between drying time and drying air temperature and specific flowrate. Mixing and recirculation of the grain at 30 min interval significantly improved the uniformity of drying, and the difference between maximum and minimum moisture content after 2 h of drying was clearly reduced to 1.9%. The study indicated the capability of 3-D CFD model to improve the design and operation of mixed flow rice husk fueled dryer to attain the required performance.
{"title":"Performance evaluation and improvement of prototype rice husk fueled mixed flow rough rice dryer using CFD model","authors":"Mulugeta Admasu Delele, Yabebal Chekole Mihret, Jochen Mellmann","doi":"10.1080/07373937.2023.2252056","DOIUrl":"https://doi.org/10.1080/07373937.2023.2252056","url":null,"abstract":"The majority of the rural areas in developing countries are not connected to the electric grid. Rice production produces a significant amount of rice husk as a byproduct/waste but this waste can be used as a source of energy for drying of the rough rice. The aim of this research was to evaluate the performance and improve the design and operation of a rice husk fueled mixed flow grain dryer for small scale rural farmers using a validated 3-D computational fluid dynamics (CFD) model. The model was applied to predict the airflow and heat and mass transfer characteristics of the designed prototype rough rice dryer. The model took into account the geometrical detail of the dryer assembly, the relevant boundary and initial conditions, and model input parameters. The results identified relatively stagnant regions at the top and the side walls of the dryer. The observed relatively high variation in drying air velocity distribution caused a relatively high variation in drying characteristics of the rice grain. The model was applied to modify the design and operation procedure of the dryer to improve the performance in terms of drying uniformity and drying time. After 2 h drying time, the difference between the maximum and minimum moisture content values for the original and modified design was 12.9% and 8.5%, respectively. There was an exponential relationship between drying time and drying air temperature and specific flowrate. Mixing and recirculation of the grain at 30 min interval significantly improved the uniformity of drying, and the difference between maximum and minimum moisture content after 2 h of drying was clearly reduced to 1.9%. The study indicated the capability of 3-D CFD model to improve the design and operation of mixed flow rice husk fueled dryer to attain the required performance.","PeriodicalId":11374,"journal":{"name":"Drying Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136307655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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