M. Miccio, G. Cascone, B. Cosenza, Michela Fraganza, P. Brachi, A. Čelan
The paper describes all the steps of a teaching activity dealing with Process Dynamics and Control and focused on the students’ use of the Control Station® simulation software. After a short software description, the paper discusses the methodology developed for coupling theoretical lecturing and practical PC-lab class, the way of involving students and the use of an interactive software environment to present automatic control of illustrative process plants. These latter comprise unit operations and simple equipment from chemical, biochemical, pharmaceutical and food industries as actual examples of abstract systems and mathematical formalisms introduced for studying processes in the context of dynamics and control. Two Project Works, which were developed by students using Control Station® and discussed by them, are presented as examples. The outcome of this 8-year teaching experience is analyzed on the basis of the number of Project Works annually delivered, the auto-evaluation tests, the final exam scores as well as the relevant answers yearly provided by the students through the Course Evaluation Forms. The final statistical results are positive.
{"title":"8 Years of Experience in Teaching Process Dynamics and Control with Control Station® Software","authors":"M. Miccio, G. Cascone, B. Cosenza, Michela Fraganza, P. Brachi, A. Čelan","doi":"10.3303/CET2186229","DOIUrl":"https://doi.org/10.3303/CET2186229","url":null,"abstract":"The paper describes all the steps of a teaching activity dealing with Process Dynamics and Control and focused on the students’ use of the Control Station® simulation software. After a short software description, the paper discusses the methodology developed for coupling theoretical lecturing and practical PC-lab class, the way of involving students and the use of an interactive software environment to present automatic control of illustrative process plants. These latter comprise unit operations and simple equipment from chemical, biochemical, pharmaceutical and food industries as actual examples of abstract systems and mathematical formalisms introduced for studying processes in the context of dynamics and control. Two Project Works, which were developed by students using Control Station® and discussed by them, are presented as examples. The outcome of this 8-year teaching experience is analyzed on the basis of the number of Project Works annually delivered, the auto-evaluation tests, the final exam scores as well as the relevant answers yearly provided by the students through the Course Evaluation Forms. The final statistical results are positive.","PeriodicalId":9695,"journal":{"name":"Chemical engineering transactions","volume":"90 1","pages":"1369-1374"},"PeriodicalIF":0.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76781403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Echeverri, Laura Ramírez, Jordan Saez, A. Escorcia
Contamination problems by heavy metals and specifically by hexavalent chromium generated by different production processes impact aquifers worldwide and require effective remediation methods for their control. The exploration of microorganisms in saline environments with the capacity to bio reduce hexavalent chromium (????6+) to trivalent chromium (????3+), allows an alternative to the use of biotechnological processes, reducing its toxicity. In the present study, marine microorganisms were isolated from water and sediments, adapted to high concentrations of hexavalent chromium, from 300ppm to 1000ppm with bio reductive potential in wastewater. Bio reduction bioassays were carried out in selective liquid and solid culture media, to which potassium dichromate (K2Cr2O7) was added. Morphological and biochemical identification was carried out with API, preserving colonies. Spectrophotometric validation was developed to evaluate (???? 6+), verifying the bio reduction efficiency in laboratory bioassays with King broth and 300 ppm of potassium dichromate. The different broths were evaluated for enrichment, being the nutritive broth and King the best, showing high turbidity and growth in a short time. Among bacteria isolated from water and sediment, the latter showed rapid growth from 18 to 24 h. Gram positive and negative bacilli (Bacillus subtilis, Bacillus brevis, Bacillus megaterium, Escherichia coli and Citrobacter kosseri) were found at 500/1000 ppm and biochemically characterized. Bio reduction percentages greater than 91% were obtained at 96 h, in concentrations of 300ppm of hexavalent chromium. Thanks to the selective isolation, tolerance and resistance to hexavalent chromium, these microorganisms proved to be bio reductive of this metal. Therefore, the use of these microorganisms on a full scale can be considered as a result for wastewater treatment where hexavalent chromium is used. Likewise, the use of microorganisms used in the bio reduction process is an alternative to Environmental Microbial Biotechnology that will bring benefits by reducing contamination.
{"title":"In Vitro Evaluation of Bio Reduction of Hexavalent Chrome by Marine Microorganisms Isolated in the Cartagena Bay for Wastewater Treatment","authors":"G. Echeverri, Laura Ramírez, Jordan Saez, A. Escorcia","doi":"10.3303/CET2186110","DOIUrl":"https://doi.org/10.3303/CET2186110","url":null,"abstract":"Contamination problems by heavy metals and specifically by hexavalent chromium generated by different production processes impact aquifers worldwide and require effective remediation methods for their control. The exploration of microorganisms in saline environments with the capacity to bio reduce hexavalent chromium (????6+) to trivalent chromium (????3+), allows an alternative to the use of biotechnological processes, reducing its toxicity. In the present study, marine microorganisms were isolated from water and sediments, adapted to high concentrations of hexavalent chromium, from 300ppm to 1000ppm with bio reductive potential in wastewater. Bio reduction bioassays were carried out in selective liquid and solid culture media, to which potassium dichromate (K2Cr2O7) was added. Morphological and biochemical identification was carried out with API, preserving colonies. Spectrophotometric validation was developed to evaluate (???? 6+), verifying the bio reduction efficiency in laboratory bioassays with King broth and 300 ppm of potassium dichromate. The different broths were evaluated for enrichment, being the nutritive broth and King the best, showing high turbidity and growth in a short time. Among bacteria isolated from water and sediment, the latter showed rapid growth from 18 to 24 h. Gram positive and negative bacilli (Bacillus subtilis, Bacillus brevis, Bacillus megaterium, Escherichia coli and Citrobacter kosseri) were found at 500/1000 ppm and biochemically characterized. Bio reduction percentages greater than 91% were obtained at 96 h, in concentrations of 300ppm of hexavalent chromium. Thanks to the selective isolation, tolerance and resistance to hexavalent chromium, these microorganisms proved to be bio reductive of this metal. Therefore, the use of these microorganisms on a full scale can be considered as a result for wastewater treatment where hexavalent chromium is used. Likewise, the use of microorganisms used in the bio reduction process is an alternative to Environmental Microbial Biotechnology that will bring benefits by reducing contamination.","PeriodicalId":9695,"journal":{"name":"Chemical engineering transactions","volume":"58 1","pages":"655-660"},"PeriodicalIF":0.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82124218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Marroccoli, F. Laguardia, M. D. Biasi, A. Telesca
The manufacture of Ordinary Portland cement (OPC) generates about 8% of all anthropogenic CO2 emissions; therefore, carbon dioxide footprint reduction represents the main challenge for the cement industry. The development of environmentally friendly binders, as alternative to OPC, absolutely represents an efficient way to cut carbon emissions. In this regard, during the last twenty years particular attention has been paid to calcium sulfoaluminate (CSA) cements thanks to their valuable technical properties as well as the environmentally friendly features mainly related to their manufacturing process. In addition, a further reduction in carbon dioxide emissions can be achieved diluting CSA cements with supplementary cementitious materials (SCMs) such as industrial wastes. In this title, biomass fly ashes (BFAs) were used as SCMs in CSA-blended cements; BFAs were preliminarily washed (W_BFAs) in order to lower their content in alkali. The influence of the ashes on both hydration properties and technical behaviour of two CSA blended cements, respectively containing 10% and 20% by mass of W_BFAs, was investigated by means of mechanical compressive strength and dimensional stability measurements associated with X-ray diffraction, differential thermal-thermogravimetric and mercury intrusion porosimetric analyses.
{"title":"Production of Eco-friendly Blended Calcium Sulfoaluminate Cements by Using Biomass-fly Ashes","authors":"M. Marroccoli, F. Laguardia, M. D. Biasi, A. Telesca","doi":"10.3303/CET2186208","DOIUrl":"https://doi.org/10.3303/CET2186208","url":null,"abstract":"The manufacture of Ordinary Portland cement (OPC) generates about 8% of all anthropogenic CO2 emissions; therefore, carbon dioxide footprint reduction represents the main challenge for the cement industry. The development of environmentally friendly binders, as alternative to OPC, absolutely represents an efficient way to cut carbon emissions. In this regard, during the last twenty years particular attention has been paid to calcium sulfoaluminate (CSA) cements thanks to their valuable technical properties as well as the environmentally friendly features mainly related to their manufacturing process. In addition, a further reduction in carbon dioxide emissions can be achieved diluting CSA cements with supplementary cementitious materials (SCMs) such as industrial wastes. In this title, biomass fly ashes (BFAs) were used as SCMs in CSA-blended cements; BFAs were preliminarily washed (W_BFAs) in order to lower their content in alkali. The influence of the ashes on both hydration properties and technical behaviour of two CSA blended cements, respectively containing 10% and 20% by mass of W_BFAs, was investigated by means of mechanical compressive strength and dimensional stability measurements associated with X-ray diffraction, differential thermal-thermogravimetric and mercury intrusion porosimetric analyses.","PeriodicalId":9695,"journal":{"name":"Chemical engineering transactions","volume":"47 1","pages":"1243-1248"},"PeriodicalIF":0.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82941803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ø. Skreiberg, M. Bugge, J. Sandquist, Fredrik Buvarp, N. Haugen
In this work, spruce wood pellets are pyrolysed in an electrically heated fixed bed reactor. Experimental campaigns have been conducted to investigate the influence of final pyrolysis temperature (600-800°C), heating rate (5-20 K/min) and purge gas composition (none, 100% N2 and 90/10% N2/O2). The instrumentation of the reactor includes transient temperature measurements in the reactor (3 locations in the vertical direction) and inside the pellets bed (3 locations in the radial direction) throughout the thermal decomposition process. Gas measurements are carried out for permanent gases (using a GC), condensables are condensed and collected and the remaining solids are also collected. Hence, the mass balance can be established. The detailed experimental results make them useful for validation of thermal decomposition modelling approaches. The experimental results show evidence of endothermal cellulose decomposition reactions as well as the exothermal char formation process. The occurrence of these two processes overlap at high heating rates and when oxygen is used in the purge gas. The two processes can be separated visually by decreasing the heating rate to 5 K/min. The separation shown in the temperature curves is confirmed by the gas analysis. The yields of CO and CH4 show a visible shoulder in the higher temperature region. The endothermic plateau visible on the temperature readings can be reduced by increasing the heating rate. Oxygen present in the purge gas will further reduce the visibility of the plateau. The amount of CO2 formed during experiments shows dependency on the oxygen in the purge gas but appears independent of the applied heating rate. The comprehensive experimental results provide both useful knowledge and a validation basis for further modelling work.
{"title":"A Detailed Experimental Study on the Thermal Decomposition Behaviour of Wood Pellets Under Inert and Oxidative Conditions in a Fixed Bed Reactor","authors":"Ø. Skreiberg, M. Bugge, J. Sandquist, Fredrik Buvarp, N. Haugen","doi":"10.3303/CET2186012","DOIUrl":"https://doi.org/10.3303/CET2186012","url":null,"abstract":"In this work, spruce wood pellets are pyrolysed in an electrically heated fixed bed reactor. Experimental campaigns have been conducted to investigate the influence of final pyrolysis temperature (600-800°C), heating rate (5-20 K/min) and purge gas composition (none, 100% N2 and 90/10% N2/O2). The instrumentation of the reactor includes transient temperature measurements in the reactor (3 locations in the vertical direction) and inside the pellets bed (3 locations in the radial direction) throughout the thermal decomposition process. Gas measurements are carried out for permanent gases (using a GC), condensables are condensed and collected and the remaining solids are also collected. Hence, the mass balance can be established. The detailed experimental results make them useful for validation of thermal decomposition modelling approaches. The experimental results show evidence of endothermal cellulose decomposition reactions as well as the exothermal char formation process. The occurrence of these two processes overlap at high heating rates and when oxygen is used in the purge gas. The two processes can be separated visually by decreasing the heating rate to 5 K/min. The separation shown in the temperature curves is confirmed by the gas analysis. The yields of CO and CH4 show a visible shoulder in the higher temperature region. The endothermic plateau visible on the temperature readings can be reduced by increasing the heating rate. Oxygen present in the purge gas will further reduce the visibility of the plateau. The amount of CO2 formed during experiments shows dependency on the oxygen in the purge gas but appears independent of the applied heating rate. The comprehensive experimental results provide both useful knowledge and a validation basis for further modelling work.","PeriodicalId":9695,"journal":{"name":"Chemical engineering transactions","volume":"3 1","pages":"67-72"},"PeriodicalIF":0.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87369677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Foglia, Marco Parlapiano, G. Cipolletta, Çağrı Akyol, A. Eusebi, M. Pisani, P. Astolfi, F. Fatone
In water scarce areas, like the Mediterranean Region where the lack of irrigation water is already limiting agricultural production, the valorization of non-concventional water resources is utmost important. Accordingly, in this study, we aimed to provide safe and locally sustainable ways of water supply for the Mediterranean agricultural sector by exploiting non-conventional water resources for irrigation purpose. In this context, pilot scale anaerobic reactors treating urban wastewater were operated coupling upflow anaerobic sludge blanket (UASB) reactor and ultrafiltration anaerobic membrane bioreactor (AnMBR). The resulting permeate is of high quality, accomplishing the EU quality standards for irrigation water reuse, also in terms of E.coli as the main microbial indicator. However, contaminants of emerging concern (CECs) can be a further limitation for safe reuse of the reclaimed water. Hence, molecularly imprinted polymers (MIPs) were further integrated as the final refining step for the selective removal of CECs. Diclofenac was used as the target compound with a removal efficiency up to 50% in the final effluent. In parallel, an intensive pilot system was operated for brine treatment through evaporation, chemical addition and precipitation, and forward osmosis, where up to 77% Mg2+ and 45% Ca2+ recovery rates were achieved. The recovered Mg-salts from the brine treatment were then used as an external source to enhance the struvite precipitation in the N- and P-rich effluent of AnMBR. The preliminary tests showed that only hydroxiapatite salts precipitated without any external P addition.
{"title":"Tailoring Non-conventional Water Resources for Sustainable and Safe Reuse in Agriculture","authors":"A. Foglia, Marco Parlapiano, G. Cipolletta, Çağrı Akyol, A. Eusebi, M. Pisani, P. Astolfi, F. Fatone","doi":"10.3303/CET2186227","DOIUrl":"https://doi.org/10.3303/CET2186227","url":null,"abstract":"In water scarce areas, like the Mediterranean Region where the lack of irrigation water is already limiting agricultural production, the valorization of non-concventional water resources is utmost important. Accordingly, in this study, we aimed to provide safe and locally sustainable ways of water supply for the Mediterranean agricultural sector by exploiting non-conventional water resources for irrigation purpose. In this context, pilot scale anaerobic reactors treating urban wastewater were operated coupling upflow anaerobic sludge blanket (UASB) reactor and ultrafiltration anaerobic membrane bioreactor (AnMBR). The resulting permeate is of high quality, accomplishing the EU quality standards for irrigation water reuse, also in terms of E.coli as the main microbial indicator. However, contaminants of emerging concern (CECs) can be a further limitation for safe reuse of the reclaimed water. Hence, molecularly imprinted polymers (MIPs) were further integrated as the final refining step for the selective removal of CECs. Diclofenac was used as the target compound with a removal efficiency up to 50% in the final effluent. In parallel, an intensive pilot system was operated for brine treatment through evaporation, chemical addition and precipitation, and forward osmosis, where up to 77% Mg2+ and 45% Ca2+ recovery rates were achieved. The recovered Mg-salts from the brine treatment were then used as an external source to enhance the struvite precipitation in the N- and P-rich effluent of AnMBR. The preliminary tests showed that only hydroxiapatite salts precipitated without any external P addition.","PeriodicalId":9695,"journal":{"name":"Chemical engineering transactions","volume":"17 1","pages":"1357-1362"},"PeriodicalIF":0.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90702928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Iovine, A. Molino, P. Casella, T. Marino, Simeone Chianese, D. Musmarra
This work presents a risk analysis of a plant that uses supercritical fluid extraction technology with carbon dioxide as a solvent to obtain bioproducts from microalgae.Given the high pressure at which it operates, the extraction plant called "Luwar" could be affected by dangerous events, such as the gas release in concentrations that are harmful to human health. In order to limit the damage, the risk analysis is of primary importance.The gas release could occur following the breakage of a pipe, which was the scenario being considered. It was analyzed using the commercial software "Phast & Safeti", an alternative tool to the methods traditionally used in the literature in hazard events of this type, such as the Threshold Limit Value-Time Weighted Average (TLV-TWA) and the Threshold Limit Value-Short Term Exposure Limit (TLV-STEL), that are defined on the basis of the characteristics of the substance dispersed in the air.Since the pressure of the extraction vessel is the highest in the system, the risk analysis was carried out on the breakage of a pipe coming out of the extractor. The results obtained made it possible to identify the risk parameters on the basis of which to make the best choices in terms of safety to cope with the type of hazard analyzed.
{"title":"Risk analysis of a supercritical fluid extraction plant affected by a gas release using a commercial software","authors":"A. Iovine, A. Molino, P. Casella, T. Marino, Simeone Chianese, D. Musmarra","doi":"10.3303/CET2186037","DOIUrl":"https://doi.org/10.3303/CET2186037","url":null,"abstract":"This work presents a risk analysis of a plant that uses supercritical fluid extraction technology with carbon dioxide as a solvent to obtain bioproducts from microalgae.Given the high pressure at which it operates, the extraction plant called \"Luwar\" could be affected by dangerous events, such as the gas release in concentrations that are harmful to human health. In order to limit the damage, the risk analysis is of primary importance.The gas release could occur following the breakage of a pipe, which was the scenario being considered. It was analyzed using the commercial software \"Phast & Safeti\", an alternative tool to the methods traditionally used in the literature in hazard events of this type, such as the Threshold Limit Value-Time Weighted Average (TLV-TWA) and the Threshold Limit Value-Short Term Exposure Limit (TLV-STEL), that are defined on the basis of the characteristics of the substance dispersed in the air.Since the pressure of the extraction vessel is the highest in the system, the risk analysis was carried out on the breakage of a pipe coming out of the extractor. The results obtained made it possible to identify the risk parameters on the basis of which to make the best choices in terms of safety to cope with the type of hazard analyzed.","PeriodicalId":9695,"journal":{"name":"Chemical engineering transactions","volume":"20 1","pages":"217-222"},"PeriodicalIF":0.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89528350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The valorization of bio-oil by catalytic cracking is a promising route for producing hydrocarbon fuels as an alternative to oil. This work addresses the cracking of bio-oil over HY zeolite catalyst (Si/Al = 15) in a continuous reaction system composed of two-step on line (thermal + catalytic). The effect that temperature has on the bio-oil conversion and the distribution of reaction products is studied. The catalyst was synthetized by agglomerating the zeolite powder with inert filler and binder, and the raw bio-oil was stabilized by adding 20 wt% MeOH. Operating condition were: 500 oC (thermal unit); 400-500 oC and space-time, 0.7 gcatalysth/gfeed (fluidized bed reactor). Attention is also paid to the catalyst deactivation, analyzing the spent catalyst samples by different techniques (N2 adsorption-desorption, adsorption/cracking/desorption of t-BA, and TGA-TPO). The results evidence a significant influence of temperature on the yield and composition of products. Although the LPG (C3-C4) hydrocarbons are the main products at 400 oC, the increase in temperature notably promotes the conversion of oxygenates into C5+ hydrocarbons, which are the majority products above 450 oC. Operation at 500 oC has the advantages of both maximizing the production of a liquid fuel composed of 74 % C5-C12 gasoline fraction (rich in 1-ring aromatics and C6-C7 cycloalkanes), and also attenuating the catalyst deactivation. Furthermore, the catalyst deactivation at 400 oC and 450 oC is faster than that observed at 500 oC, despite the lower formation of coke. This fact is explained by the different nature and location of the coke deposited in the porous structure of the catalyst.
{"title":"Product Distribution and Deactivation of Y-zeolite Based Catalyst in the Catalytic Cracking of Biomass Pyrolysis Oil","authors":"Beatriz Valle, J. Bilbao, A. Aguayo, A. Gayubo","doi":"10.3303/CET2186145","DOIUrl":"https://doi.org/10.3303/CET2186145","url":null,"abstract":"The valorization of bio-oil by catalytic cracking is a promising route for producing hydrocarbon fuels as an alternative to oil. This work addresses the cracking of bio-oil over HY zeolite catalyst (Si/Al = 15) in a continuous reaction system composed of two-step on line (thermal + catalytic). The effect that temperature has on the bio-oil conversion and the distribution of reaction products is studied. The catalyst was synthetized by agglomerating the zeolite powder with inert filler and binder, and the raw bio-oil was stabilized by adding 20 wt% MeOH. Operating condition were: 500 oC (thermal unit); 400-500 oC and space-time, 0.7 gcatalysth/gfeed (fluidized bed reactor). Attention is also paid to the catalyst deactivation, analyzing the spent catalyst samples by different techniques (N2 adsorption-desorption, adsorption/cracking/desorption of t-BA, and TGA-TPO). The results evidence a significant influence of temperature on the yield and composition of products. Although the LPG (C3-C4) hydrocarbons are the main products at 400 oC, the increase in temperature notably promotes the conversion of oxygenates into C5+ hydrocarbons, which are the majority products above 450 oC. Operation at 500 oC has the advantages of both maximizing the production of a liquid fuel composed of 74 % C5-C12 gasoline fraction (rich in 1-ring aromatics and C6-C7 cycloalkanes), and also attenuating the catalyst deactivation. Furthermore, the catalyst deactivation at 400 oC and 450 oC is faster than that observed at 500 oC, despite the lower formation of coke. This fact is explained by the different nature and location of the coke deposited in the porous structure of the catalyst.","PeriodicalId":9695,"journal":{"name":"Chemical engineering transactions","volume":"31 1","pages":"865-870"},"PeriodicalIF":0.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88479366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tommaso Iannaccone, G. E. Scarponi, B. Jeong, V. Cozzani
Decarbonization represent one of the main challenges of the maritime transport sector for the near future. As recent international environmental regulations have set more stringent emission limits, the use of liquefied natural gas (LNG) as alternative ship fuel has proven to be a viable and less-polluting solution, compared to conventional oil-based fuels. However, LNG is a highly flammable substance and safety aspects need to be assessed thoroughly, especially for its use on board passenger ships.Two different gas engine concepts are typically used for ship propulsion: Low-Pressure Dual Fuel (LPDF) and High-Pressure Dual Fuel (HPDF) engines. Regardless of the gas engine technology, the fuel gas supply system process equipment is located inside a specific enclosed space, the fuel preparation room (FPR), that can be sited below deck. Given this background, this study aims to investigate the consequences of LNG pool fires occurring inside a confined space, assessing the influence of different operating conditions. Credible loss of containment events were identified to define the characteristics of LNG pools. Furthermore, LNG pool fires were simulated using the fire dynamic simulator (FDS) to estimate the radiation heat flux received by the process equipment installed inside the FPR and to assess the possibility of experiencing accident escalation on board. To evaluate the effect of forced mechanical ventilation of the FPR, two different cases were modelled: one assuming the standard functioning of the ventilation system, while the other one considered a halted air supply inside the FPR with a working exhaust system only. The outcomes of this study provide useful data for the consequence estimation of small-scale LNG pool fires occurring inside enclosed spaces, also addressing the possibility of accident escalation on board LNG-fuelled ships.
{"title":"Assessment of Lng Fire Scenarios on Board of Lng-fuelled Ships","authors":"Tommaso Iannaccone, G. E. Scarponi, B. Jeong, V. Cozzani","doi":"10.3303/CET2186065","DOIUrl":"https://doi.org/10.3303/CET2186065","url":null,"abstract":"Decarbonization represent one of the main challenges of the maritime transport sector for the near future. As recent international environmental regulations have set more stringent emission limits, the use of liquefied natural gas (LNG) as alternative ship fuel has proven to be a viable and less-polluting solution, compared to conventional oil-based fuels. However, LNG is a highly flammable substance and safety aspects need to be assessed thoroughly, especially for its use on board passenger ships.Two different gas engine concepts are typically used for ship propulsion: Low-Pressure Dual Fuel (LPDF) and High-Pressure Dual Fuel (HPDF) engines. Regardless of the gas engine technology, the fuel gas supply system process equipment is located inside a specific enclosed space, the fuel preparation room (FPR), that can be sited below deck. Given this background, this study aims to investigate the consequences of LNG pool fires occurring inside a confined space, assessing the influence of different operating conditions. Credible loss of containment events were identified to define the characteristics of LNG pools. Furthermore, LNG pool fires were simulated using the fire dynamic simulator (FDS) to estimate the radiation heat flux received by the process equipment installed inside the FPR and to assess the possibility of experiencing accident escalation on board. To evaluate the effect of forced mechanical ventilation of the FPR, two different cases were modelled: one assuming the standard functioning of the ventilation system, while the other one considered a halted air supply inside the FPR with a working exhaust system only. The outcomes of this study provide useful data for the consequence estimation of small-scale LNG pool fires occurring inside enclosed spaces, also addressing the possibility of accident escalation on board LNG-fuelled ships.","PeriodicalId":9695,"journal":{"name":"Chemical engineering transactions","volume":"43 1","pages":"385-390"},"PeriodicalIF":0.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75732038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Crude oil has different characteristics according to its origin, and this difference causes suboptimal operation if not considered. Similar to other refinery operations, hydrodesulfurization suffers from lacking this knowledge. Information on the true boiling point curve of the feed, next to its sulfur concentration, can be used to optimize the operating temperature. In this work, an optimization problem is demonstrated for two manipulated temperatures of the system and solved by using a gradient-based and a gradient-free algorithm. While the gradient based solution has a single objective of minimum sulfur content, the gradient-free solution has three objectives: minimum sulfur, inlet temperature, and secondary hydrogen flow rate. A continuous lumping model is used to predict the temperature and sulfur responses of a real hydrodesulfurization plant. An adaptive approach is preferred for the model to cope with the catalyst deactivation interference on the product sulfur content constraint. The effect of changing feed on optimality is demonstrated by using eight types of feeds with varying true boiling point and sulfur content. In addition to that, the impact of catalyst age is shown on similar feed processed on different dates.
{"title":"Crude-specific Optimal Operation of Hydrodesulfurization","authors":"Esin Iplik, I. Aslanidou, K. Kyprianidis","doi":"10.3303/CET2186161","DOIUrl":"https://doi.org/10.3303/CET2186161","url":null,"abstract":"Crude oil has different characteristics according to its origin, and this difference causes suboptimal operation if not considered. Similar to other refinery operations, hydrodesulfurization suffers from lacking this knowledge. Information on the true boiling point curve of the feed, next to its sulfur concentration, can be used to optimize the operating temperature. In this work, an optimization problem is demonstrated for two manipulated temperatures of the system and solved by using a gradient-based and a gradient-free algorithm. While the gradient based solution has a single objective of minimum sulfur content, the gradient-free solution has three objectives: minimum sulfur, inlet temperature, and secondary hydrogen flow rate. A continuous lumping model is used to predict the temperature and sulfur responses of a real hydrodesulfurization plant. An adaptive approach is preferred for the model to cope with the catalyst deactivation interference on the product sulfur content constraint. The effect of changing feed on optimality is demonstrated by using eight types of feeds with varying true boiling point and sulfur content. In addition to that, the impact of catalyst age is shown on similar feed processed on different dates.","PeriodicalId":9695,"journal":{"name":"Chemical engineering transactions","volume":"73 1","pages":"961-966"},"PeriodicalIF":0.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84304633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ariel V. Melendres, R. Cruz, Mel Bryan L. Espenilla, A. M. Monsada
Polyamide epoxy containing superabsorbent polymer (SAP) was investigated for its absorbency property and its application in the inhibition of corrosion in carbon steel. The type of SAP was sodium polyacrylate with relatively low crosslinking density. Fine particles of SAP was mixed with epoxy resin and subsequently the polyamide hardener was added allowing the polymerization of epoxy resin to occur while the SAP is dispersed within the polymer matrix. Prior to this, the SAP used for this application was examined in terms of its absorbency property in pure water and in sodium chloride solutions. The composite material, i.e. cured epoxy with SAP, was likewise examined for its absorbency property. Results showed decreased absorbency of pure SAP in sodium chloride solution compared with pure water, and the same trend was exhibited in the composite material but with much lower absorbency. The composite material was applied on the surface of carbon steel of 40 mm x 100 mm and thickness of 0.7mm and tested for anticorrosion property. The composite material gave better results than the control material of polyamide epoxy without SAP. The better corrosion resistance exhibited by the composite materials could be attributed to the self-healing property of SAP.
研究了聚酰胺环氧高吸水性聚合物(SAP)的吸光性能及其在碳钢缓蚀中的应用。SAP的类型为聚丙烯酸钠，交联密度相对较低。SAP的细颗粒与环氧树脂混合，随后加入聚酰胺硬化剂，使环氧树脂发生聚合，而SAP分散在聚合物基体中。在此之前，对用于该应用的SAP在纯水和氯化钠溶液中的吸收性能进行了测试。复合材料，即固化环氧树脂与SAP，同样检查其吸收性能。结果表明，与纯水相比，纯SAP在氯化钠溶液中的吸光度降低，复合材料的吸光度也有相同的变化趋势，但吸光度要低得多。将复合材料涂在厚度为0.7mm、厚度为40 mm × 100 mm的碳钢表面，进行了防腐性能测试。复合材料的抗腐蚀性能优于不含SAP的对照材料聚酰胺环氧树脂，其良好的耐腐蚀性能可归因于SAP的自修复性能。
{"title":"Absorbency and Corrosion Inhibition Property of Polyamide Epoxy and Superabsorbent Polymer Composite Material","authors":"Ariel V. Melendres, R. Cruz, Mel Bryan L. Espenilla, A. M. Monsada","doi":"10.3303/CET2186217","DOIUrl":"https://doi.org/10.3303/CET2186217","url":null,"abstract":"Polyamide epoxy containing superabsorbent polymer (SAP) was investigated for its absorbency property and its application in the inhibition of corrosion in carbon steel. The type of SAP was sodium polyacrylate with relatively low crosslinking density. Fine particles of SAP was mixed with epoxy resin and subsequently the polyamide hardener was added allowing the polymerization of epoxy resin to occur while the SAP is dispersed within the polymer matrix. Prior to this, the SAP used for this application was examined in terms of its absorbency property in pure water and in sodium chloride solutions. The composite material, i.e. cured epoxy with SAP, was likewise examined for its absorbency property. Results showed decreased absorbency of pure SAP in sodium chloride solution compared with pure water, and the same trend was exhibited in the composite material but with much lower absorbency. The composite material was applied on the surface of carbon steel of 40 mm x 100 mm and thickness of 0.7mm and tested for anticorrosion property. The composite material gave better results than the control material of polyamide epoxy without SAP. The better corrosion resistance exhibited by the composite materials could be attributed to the self-healing property of SAP.","PeriodicalId":9695,"journal":{"name":"Chemical engineering transactions","volume":"22 1","pages":"1297-1302"},"PeriodicalIF":0.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85099323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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