Hidden Markov models (HMMs) have been recently used for fault detection and prediction in continuous industrial processes; however, the expected maximum (EM) algorithm in the HMM has local optimality problems and cannot accurately find the fault root cause variables in complex industrial processes with high-dimensional data and strong variable coupling. To alleviate this problem, a hidden Markov model-Bayesian network (HMM-BN) hybrid model is proposed to alleviate the local optimum problem in the EM algorithm and diagnose the fault root cause variable. Firstly, the model introduces expert empirical knowledge for constructing BN to accurately diagnose the fault root cause variable. Then, the EM algorithm is improved by sequential and parallel learning to alleviate the initial sensitivity and local optimum problems. Finally, the log-likelihood estimates (LL) calculated by the improved hidden Markov model provide empirical evidence for the BN and give fault detection, prediction, and root cause variable detection results based on information about the similar increasing and decreasing patterns of LL for the training data and the online data. Combining the Tennessee Eastman (TE) process and the continuously stirred tank reactor (CSTR) process, the feasibility and effectiveness of the model are verified. The results show that the model can not only find the fault in time but also find the cause of the fault accurately.
{"title":"Fault Diagnosis and Prediction of Continuous Industrial Processes Based on Hidden Markov Model-Bayesian Network Hybrid Model","authors":"Jiarula Yasenjiang, Chenxing Xu, Sheng Zhang, Xin Zhang","doi":"10.1155/2022/3511073","DOIUrl":"https://doi.org/10.1155/2022/3511073","url":null,"abstract":"Hidden Markov models (HMMs) have been recently used for fault detection and prediction in continuous industrial processes; however, the expected maximum (EM) algorithm in the HMM has local optimality problems and cannot accurately find the fault root cause variables in complex industrial processes with high-dimensional data and strong variable coupling. To alleviate this problem, a hidden Markov model-Bayesian network (HMM-BN) hybrid model is proposed to alleviate the local optimum problem in the EM algorithm and diagnose the fault root cause variable. Firstly, the model introduces expert empirical knowledge for constructing BN to accurately diagnose the fault root cause variable. Then, the EM algorithm is improved by sequential and parallel learning to alleviate the initial sensitivity and local optimum problems. Finally, the log-likelihood estimates (LL) calculated by the improved hidden Markov model provide empirical evidence for the BN and give fault detection, prediction, and root cause variable detection results based on information about the similar increasing and decreasing patterns of LL for the training data and the online data. Combining the Tennessee Eastman (TE) process and the continuously stirred tank reactor (CSTR) process, the feasibility and effectiveness of the model are verified. The results show that the model can not only find the fault in time but also find the cause of the fault accurately.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44742208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Combustion and flame characteristics of laminar methane/air and n-butane/air flames in a 3D-printed micro-slot burner is compared and reported in this study. The stability limit, flame appearance, and emission performance are investigated experimentally. In addition, past research on conventional burners is compared with the results of this study throughout the paper. The construction of this micro-slot burner was met by selective laser melting (SLM) process. Flame characteristics such as lift-off height, length, visible area, maximum width, and neck width are obtained using an image processing algorithm and are examined at different fuel and airflow rates. The results show that the blow-out limits of methane/air and n-butane/air flames are almost the same when compared at the same volume flow rates, although the methane/air flames are more stable than n-butane/air flames at the same thermal input powers. A region of interesting rope-like oscillatory flames (that has never been seen before in conventional burners) is observed in a small portion of a stable region for n-butane with a period ranging from 75.0 to 210.0 m s . It is also observed that the fuel type and fuel and airflow rates affect the flame shape and appearance and the flames formed by heavier fuel (n-butane) have longer length, lift-off height, maximum width, and visible area and lower neck width. Furthermore, methane/air flames exhibit lower values of C O and higher values of N O x in the flue gas when compared to n-butane/air flames.
{"title":"Comparative Study on Combustion and Flame Characteristics of Laminar Methane/Air and N-Butane/Air Flames in a Micro-Slot Burner","authors":"Soroush Sheykhbaglou, S. M. Robati","doi":"10.1155/2022/1821147","DOIUrl":"https://doi.org/10.1155/2022/1821147","url":null,"abstract":"Combustion and flame characteristics of laminar methane/air and n-butane/air flames in a 3D-printed micro-slot burner is compared and reported in this study. The stability limit, flame appearance, and emission performance are investigated experimentally. In addition, past research on conventional burners is compared with the results of this study throughout the paper. The construction of this micro-slot burner was met by selective laser melting (SLM) process. Flame characteristics such as lift-off height, length, visible area, maximum width, and neck width are obtained using an image processing algorithm and are examined at different fuel and airflow rates. The results show that the blow-out limits of methane/air and n-butane/air flames are almost the same when compared at the same volume flow rates, although the methane/air flames are more stable than n-butane/air flames at the same thermal input powers. A region of interesting rope-like oscillatory flames (that has never been seen before in conventional burners) is observed in a small portion of a stable region for n-butane with a period ranging from \u0000 \u0000 75.0\u0000 \u0000 to \u0000 \u0000 210.0\u0000 \u0000 m\u0000 s\u0000 \u0000 . It is also observed that the fuel type and fuel and airflow rates affect the flame shape and appearance and the flames formed by heavier fuel (n-butane) have longer length, lift-off height, maximum width, and visible area and lower neck width. Furthermore, methane/air flames exhibit lower values of \u0000 \u0000 C\u0000 O\u0000 \u0000 and higher values of \u0000 \u0000 \u0000 \u0000 N\u0000 O\u0000 \u0000 \u0000 x\u0000 \u0000 \u0000 \u0000 in the flue gas when compared to n-butane/air flames.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44503204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. García-Morales, R. Escobar-Jiménez, O. J. Ramos-Negrón, D. A. Carbot-Rojas, M. Cervantes-Bobadilla, J. Gómez-Aguilar
In this work, an internal combustion (IC) engine air-fuel ratio (AFR) control system is presented and evaluated by simulation. The control scheme aims to regulate the overall air-fuel ratio (AFRoverall) in an IC engine fueled with a hydrogen-enriched ethanol-gasoline blend (E10) as fast as possible. The control scheme designed and developed in this work considers two control laws, a feedback control law to regulate the hydrogen and adaptive nonlinear control law for controlling the E10 mass flow injection. The main contribution of this work is the reduction of the number of controllers used for controlling the overall air-fuel ratio since other control strategies use two controllers for controlling the E10 mass flow injection. Simulation results have shown the effectiveness of the new control scheme.
{"title":"Design of an Adaptive Control to Feed Hydrogen-Enriched Ethanol-Gasoline Blend to an Internal Combustion Engine","authors":"J. García-Morales, R. Escobar-Jiménez, O. J. Ramos-Negrón, D. A. Carbot-Rojas, M. Cervantes-Bobadilla, J. Gómez-Aguilar","doi":"10.1155/2022/7413554","DOIUrl":"https://doi.org/10.1155/2022/7413554","url":null,"abstract":"In this work, an internal combustion (IC) engine air-fuel ratio (AFR) control system is presented and evaluated by simulation. The control scheme aims to regulate the overall air-fuel ratio (AFRoverall) in an IC engine fueled with a hydrogen-enriched ethanol-gasoline blend (E10) as fast as possible. The control scheme designed and developed in this work considers two control laws, a feedback control law to regulate the hydrogen and adaptive nonlinear control law for controlling the E10 mass flow injection. The main contribution of this work is the reduction of the number of controllers used for controlling the overall air-fuel ratio since other control strategies use two controllers for controlling the E10 mass flow injection. Simulation results have shown the effectiveness of the new control scheme.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43371557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Emmanuela Kwao-Boateng, Terza Anokye-Poku, Anthony N. P. Agyemang, Michael Kwadwo Fokuo
Despite having detrimental impacts on the environment and human health, used engine oil is not properly disposed of in Ghana. However, used engine oil can be a valuable resource when recycled. This study investigates the recovery of base oils from used engine oils collected in one Ghanaian municipality. The used engine oils are re-refined either through acid-clay treatment or solvent extraction. Pour point, density, viscosity index, and total acid number of used engine oil and re-refined oils were measured in order to evaluate the two re-refining processes used and assess whether it is appropriate to reuse the re-refined oils as base oils. The pour point, total acid number, and viscosity index of the re-refined oils were significantly different from those of the used engine oils. The density of the re-refined oils varied little from that of the used engine oils (by 0.83% to 6.65%). These changes indicate the separation of some components, primarily impurities, from used engine oil as a result of re-refining. Compared to solvent extraction, acid-clay treatment was found to be less selective. When nitric acid or sulphuric acid was used, acid-clay treatment often produced group I and II base oils, whereas hydrochloric acid typically produced group III base oils. Also, the solvent extraction process frequently yielded oils with very high viscosity indices comparable to group III base oils. It is recommended that the type of base oil preferred for the production of new lubricants should be taken into account when deciding on a specific method for re-refining used engine oil.
{"title":"Re-refining Used Engine Oil in Ghana Using Solvent Extraction and Acid-Clay Treatment","authors":"Emmanuela Kwao-Boateng, Terza Anokye-Poku, Anthony N. P. Agyemang, Michael Kwadwo Fokuo","doi":"10.1155/2022/6344409","DOIUrl":"https://doi.org/10.1155/2022/6344409","url":null,"abstract":"Despite having detrimental impacts on the environment and human health, used engine oil is not properly disposed of in Ghana. However, used engine oil can be a valuable resource when recycled. This study investigates the recovery of base oils from used engine oils collected in one Ghanaian municipality. The used engine oils are re-refined either through acid-clay treatment or solvent extraction. Pour point, density, viscosity index, and total acid number of used engine oil and re-refined oils were measured in order to evaluate the two re-refining processes used and assess whether it is appropriate to reuse the re-refined oils as base oils. The pour point, total acid number, and viscosity index of the re-refined oils were significantly different from those of the used engine oils. The density of the re-refined oils varied little from that of the used engine oils (by 0.83% to 6.65%). These changes indicate the separation of some components, primarily impurities, from used engine oil as a result of re-refining. Compared to solvent extraction, acid-clay treatment was found to be less selective. When nitric acid or sulphuric acid was used, acid-clay treatment often produced group I and II base oils, whereas hydrochloric acid typically produced group III base oils. Also, the solvent extraction process frequently yielded oils with very high viscosity indices comparable to group III base oils. It is recommended that the type of base oil preferred for the production of new lubricants should be taken into account when deciding on a specific method for re-refining used engine oil.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41696645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nasrin Zahedi, Bahare Dehdashti, F. Mohammadi, M. Razaghi, Zeynab Moradmand, M. Amin
Atenolol (ATN) is a drug that is widely used to treat some heart diseases, and since it cannot be completely decomposed in the human body, some amounts of it are found in surface water. These amounts may bring risks to the environment and humans, and for this reason, its removal is a must. In the present study, the combined sono-electro-persulfate method was used for ATN removal. Based on the design of the experiment conducted by response surface methodology (RSM), the effects of 5 main factors (pH, time, PS concentration, current intensity, and initial ATN concentration) have been investigated at 5 levels. After passing the test steps in different conditions, the remaining amount of ATN has been measured by high-performance liquid chromatography (HPLC). Finally, an adaptive neuro-fuzzy inference system (ANFIS) with 99.63% accuracy and a genetic algorithm (GA) were used to analyze and interpret data and predict optimal conditions. The obtained results indicate the possibility of a maximum efficiency of 99.8% in the mentioned conditions (Ph of 7.4, time of 18 min, PS concentration of 2000 mg/L, current intensity of 3.35 A, and initial ATN concentration of 11.2 mg/L). According to the obtained results, the initial concentration of ATN can be considered as the most effective factor in this process, and the best Ph range for this experiment was the neutral range. The sono-electro persulfate process can be mentioned as a new and effective method for removing ATN from water sources.
{"title":"Using Sono-Electro-Persulfate Process for Atenolol Removal from Aqueous Solutions: Prediction and Optimization with the ANFIS Model and Genetic Algorithm","authors":"Nasrin Zahedi, Bahare Dehdashti, F. Mohammadi, M. Razaghi, Zeynab Moradmand, M. Amin","doi":"10.1155/2022/1812776","DOIUrl":"https://doi.org/10.1155/2022/1812776","url":null,"abstract":"Atenolol (ATN) is a drug that is widely used to treat some heart diseases, and since it cannot be completely decomposed in the human body, some amounts of it are found in surface water. These amounts may bring risks to the environment and humans, and for this reason, its removal is a must. In the present study, the combined sono-electro-persulfate method was used for ATN removal. Based on the design of the experiment conducted by response surface methodology (RSM), the effects of 5 main factors (pH, time, PS concentration, current intensity, and initial ATN concentration) have been investigated at 5 levels. After passing the test steps in different conditions, the remaining amount of ATN has been measured by high-performance liquid chromatography (HPLC). Finally, an adaptive neuro-fuzzy inference system (ANFIS) with 99.63% accuracy and a genetic algorithm (GA) were used to analyze and interpret data and predict optimal conditions. The obtained results indicate the possibility of a maximum efficiency of 99.8% in the mentioned conditions (Ph of 7.4, time of 18 min, PS concentration of 2000 mg/L, current intensity of 3.35 A, and initial ATN concentration of 11.2 mg/L). According to the obtained results, the initial concentration of ATN can be considered as the most effective factor in this process, and the best Ph range for this experiment was the neutral range. The sono-electro persulfate process can be mentioned as a new and effective method for removing ATN from water sources.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48610394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Ismail, Hamdy Kashtoh, M. A. Betiha, Salem A. Abu Amr, Kwan-Hyun Baek, N. El-Gendy
In this study, evaporation-induced self-assembly was applied to prepare amine-functionalized nano-silica (NH2-Pr-SBA-15). That was simply used to immobilize Bacillus stratosphericus PSP8 lipase (E–NH2–Pr-SBA-15), producing a nanobiocatalyst with good stability under vigorous shaking and a maximum lipase activity of 45 ± 2 U/mL. High-resolution X-ray diffractometer, Fourier transform infrared spectroscopy, N2 adsorption-desorption, field-emission scanning electron, and high-resolution transmission electron microscopic analyses proved the successful SBA-15 functionalization and enzyme immobilization. Response surface methodology based on a 1/2 fraction-three-levels face center composite design was applied to optimize the biodiesel transesterification process. This expressed efficient percentage conversion (97.85%) and biodiesel yield (97.01%) under relatively mild operating conditions: 3.12 : 1 methanol to oil ratio, 3.08 wt.% E–NH2–Pr-SBA-15 loading, 48.6°C, 3.19 h at a mixing rate of 495.53 rpm. E–NH2–Pr-SBA-15 proved to have a long lifetime, operational stability, and reusability.
{"title":"Valorization of Waste Cooking Oil into Biodiesel via Bacillus stratosphericus Lipase Amine-Functionalized Mesoporous SBA-15 Nanobiocatalyst","authors":"A. Ismail, Hamdy Kashtoh, M. A. Betiha, Salem A. Abu Amr, Kwan-Hyun Baek, N. El-Gendy","doi":"10.1155/2022/7899996","DOIUrl":"https://doi.org/10.1155/2022/7899996","url":null,"abstract":"In this study, evaporation-induced self-assembly was applied to prepare amine-functionalized nano-silica (NH2-Pr-SBA-15). That was simply used to immobilize Bacillus stratosphericus PSP8 lipase (E–NH2–Pr-SBA-15), producing a nanobiocatalyst with good stability under vigorous shaking and a maximum lipase activity of 45 ± 2 U/mL. High-resolution X-ray diffractometer, Fourier transform infrared spectroscopy, N2 adsorption-desorption, field-emission scanning electron, and high-resolution transmission electron microscopic analyses proved the successful SBA-15 functionalization and enzyme immobilization. Response surface methodology based on a 1/2 fraction-three-levels face center composite design was applied to optimize the biodiesel transesterification process. This expressed efficient percentage conversion (97.85%) and biodiesel yield (97.01%) under relatively mild operating conditions: 3.12 : 1 methanol to oil ratio, 3.08 wt.% E–NH2–Pr-SBA-15 loading, 48.6°C, 3.19 h at a mixing rate of 495.53 rpm. E–NH2–Pr-SBA-15 proved to have a long lifetime, operational stability, and reusability.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48948471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research investigates the optimum operating conditions related to the adsorption of nitrogen gas from ambient air on zeolite Li-LSX to produce oxygen gas by the pressure-vacuum swing adsorption process. Experiments were performed using a column (4 cm inside diameter and 17 cm length) packed with different heights of packing (h) of zeolite (9, 12, and 16 cm) from 0.4 to 0.8 mm diameter pellets. At each packing height, different flow rates (f) (2, 4, 6, 8, and 10 L·min−1) for different input pressures ( p ) (0.5, 1, 1.5, 2, and 2.5 bar) were used to detect their effects on the purity of produced oxygen as percentage volume of the outlet air stream. The results showed that the purity of produced oxygen increased with increasing packing height, pressure, and flowrate to a specific limit. The maximum purity obtained was 73.15% at 16 cm packing height, 2.5 bar input pressure, and 6 L·min−1 inlet flowrate, and the productivity was equal to 18 mmol·(Kg·s)−1 at these conditions. A response surface methodology was used to determine the most influential variables and their interactions. The results confirmed the strong effects of the input pressure, the packing height, and to a lesser extent, the flowrate. A quadratic model was predicted based on the experimental result and assessed statistically. The impacts of quadratic terms in the model were in the order: of p ∗ p > p ∗ h > p ∗ f . The model was applied to predict the operating conditions of 95% purity of oxygen.
{"title":"Methodological Approach for Optimizing Production of Oxygen by Adsorption of Nitrogen from Air using Zeolite Li-LSX","authors":"Marwa Al-Yousuf, R. Almilly, Riyadh Kamil","doi":"10.1155/2022/7254646","DOIUrl":"https://doi.org/10.1155/2022/7254646","url":null,"abstract":"This research investigates the optimum operating conditions related to the adsorption of nitrogen gas from ambient air on zeolite Li-LSX to produce oxygen gas by the pressure-vacuum swing adsorption process. Experiments were performed using a column (4 cm inside diameter and 17 cm length) packed with different heights of packing (h) of zeolite (9, 12, and 16 cm) from 0.4 to 0.8 mm diameter pellets. At each packing height, different flow rates (f) (2, 4, 6, 8, and 10 L·min−1) for different input pressures (\u0000 \u0000 p\u0000 \u0000 ) (0.5, 1, 1.5, 2, and 2.5 bar) were used to detect their effects on the purity of produced oxygen as percentage volume of the outlet air stream. The results showed that the purity of produced oxygen increased with increasing packing height, pressure, and flowrate to a specific limit. The maximum purity obtained was 73.15% at 16 cm packing height, 2.5 bar input pressure, and 6 L·min−1 inlet flowrate, and the productivity was equal to 18 mmol·(Kg·s)−1 at these conditions. A response surface methodology was used to determine the most influential variables and their interactions. The results confirmed the strong effects of the input pressure, the packing height, and to a lesser extent, the flowrate. A quadratic model was predicted based on the experimental result and assessed statistically. The impacts of quadratic terms in the model were in the order: of \u0000 \u0000 p\u0000 ∗\u0000 p\u0000 >\u0000 p\u0000 ∗\u0000 h\u0000 >\u0000 p\u0000 ∗\u0000 f\u0000 \u0000 . The model was applied to predict the operating conditions of 95% purity of oxygen.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44112143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fahimeh Shamseali, F. Mohammadi, H. Pourzamani, Mahsa Janati
The process of electrochemical denitrification is applied with the aim of converting nitrate ( NO 3 − ) to N2 gas by reducing nitrate and oxidizing by-products such as ammonia ( NH 4 + ). In this study, Ti/RuO2 and graphite were used as anode and cathode electrodes, respectively, to treat synthetic aqueous solutions containing different concentrations of nitrate ions. Nitrate initial concentration (2.75–55 mg NO3-N/lit), voltage (2.5–30 V), pH (3–13), electrode distance (ED = 0.5–3.5 cm), and reaction time (10–180 min) were the main studied operating parameters for the electrochemical denitrification (ECD) reactor. The experiments were designed using the central composite design (CCD) method. The experimental results were modeled with the response surface methodology (RSM) technique. Scanning electron microscope (SEM), X-ray diffraction analyzer (XRD), and Fourier transform infrared spectroscopy (FTIR) characterized electrodes were performed before and after all experiments. Optimization and sensitivity analysis was performed using the Monte Carlo simulation (MSC) approach. The energy consumption and current efficiency were calculated for the ECD reactor. Kinetic models of zero, first, and second order were evaluated, and the second-order model was selected as the best kinetic model. Also, the effect of adding monovalent, divalent salts, and organic compounds to the process was evaluated. Finally, three nitrate-contaminated water wells were selected near agricultural lands as real samples and investigated the performance of the ECD process on the samples. The performance of the ECD reactor for the real samples showed some decrease compared to the synthetic samples.
{"title":"Electrochemical Denitrification of Synthetic Aqueous Solution and Actual Contaminated Well Water: RSM Modeling, Kinetic Study, Monte Carlo Optimization, and Sensitivity Analysis","authors":"Fahimeh Shamseali, F. Mohammadi, H. Pourzamani, Mahsa Janati","doi":"10.1155/2022/1374993","DOIUrl":"https://doi.org/10.1155/2022/1374993","url":null,"abstract":"The process of electrochemical denitrification is applied with the aim of converting nitrate (\u0000 \u0000 \u0000 NO\u0000 3\u0000 −\u0000 \u0000 \u0000 ) to N2 gas by reducing nitrate and oxidizing by-products such as ammonia (\u0000 \u0000 \u0000 NH\u0000 4\u0000 +\u0000 \u0000 \u0000 ). In this study, Ti/RuO2 and graphite were used as anode and cathode electrodes, respectively, to treat synthetic aqueous solutions containing different concentrations of nitrate ions. Nitrate initial concentration (2.75–55 mg NO3-N/lit), voltage (2.5–30 V), pH (3–13), electrode distance (ED = 0.5–3.5 cm), and reaction time (10–180 min) were the main studied operating parameters for the electrochemical denitrification (ECD) reactor. The experiments were designed using the central composite design (CCD) method. The experimental results were modeled with the response surface methodology (RSM) technique. Scanning electron microscope (SEM), X-ray diffraction analyzer (XRD), and Fourier transform infrared spectroscopy (FTIR) characterized electrodes were performed before and after all experiments. Optimization and sensitivity analysis was performed using the Monte Carlo simulation (MSC) approach. The energy consumption and current efficiency were calculated for the ECD reactor. Kinetic models of zero, first, and second order were evaluated, and the second-order model was selected as the best kinetic model. Also, the effect of adding monovalent, divalent salts, and organic compounds to the process was evaluated. Finally, three nitrate-contaminated water wells were selected near agricultural lands as real samples and investigated the performance of the ECD process on the samples. The performance of the ECD reactor for the real samples showed some decrease compared to the synthetic samples.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48624451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reza Kalantar Feeoj, Sayed Masoud Alavi Eshkaftaki, Iman Kazemi Asfeh, M. Jahangiri
Micromixers are crucial parts of microfluidic systems when it comes to efficiency and precision, as mixing is the central process in most relevant applications, including medical diagnosis, chemical production, and drug discovery. In view of the importance of improving the mixing quality, for the first time, the present work investigates the simultaneous effects of mixing chamber geometry (circular, hexagonal, and octagonal), electric field frequency (5, 7, 10, and 15 Hz), inlet velocity (0.1-0.2 mm·s−1), and phase difference (0-π) on the flow inside an electroosmotic micromixer using the finite-element tool COMSOL Multiphysics 5.4 to optimize the process and achieve homogeneous mixing. The flow-field, concentration-field, and electric-field equations were coupled and solved simultaneously. The results of this research indicated that at a given inlet velocity and a specific frequency range, as frequency increases, more mixing occurs in a smaller chamber, and as the inlet velocity increases, more mixing occurs in a smaller chamber at a higher frequency. Moreover, the highest mixing level (98.16%) was obtained with a 0.1 mm·s−1 inlet velocity, 10 Hz frequency, and π/2 phase difference in a hexagonal chamber.
{"title":"Finite-Element Simulation of Electroosmotic Mixing: A Study of the Simultaneous Effects of Working Parameters for Optimization","authors":"Reza Kalantar Feeoj, Sayed Masoud Alavi Eshkaftaki, Iman Kazemi Asfeh, M. Jahangiri","doi":"10.1155/2022/9957189","DOIUrl":"https://doi.org/10.1155/2022/9957189","url":null,"abstract":"Micromixers are crucial parts of microfluidic systems when it comes to efficiency and precision, as mixing is the central process in most relevant applications, including medical diagnosis, chemical production, and drug discovery. In view of the importance of improving the mixing quality, for the first time, the present work investigates the simultaneous effects of mixing chamber geometry (circular, hexagonal, and octagonal), electric field frequency (5, 7, 10, and 15 Hz), inlet velocity (0.1-0.2 mm·s−1), and phase difference (0-π) on the flow inside an electroosmotic micromixer using the finite-element tool COMSOL Multiphysics 5.4 to optimize the process and achieve homogeneous mixing. The flow-field, concentration-field, and electric-field equations were coupled and solved simultaneously. The results of this research indicated that at a given inlet velocity and a specific frequency range, as frequency increases, more mixing occurs in a smaller chamber, and as the inlet velocity increases, more mixing occurs in a smaller chamber at a higher frequency. Moreover, the highest mixing level (98.16%) was obtained with a 0.1 mm·s−1 inlet velocity, 10 Hz frequency, and π/2 phase difference in a hexagonal chamber.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44570608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Muhd Arshad Amin, H. Shukor, L. Yin, F. Kasim, N. F. Shoparwe, M. Z. Makhtar, A. Yaser
Biomethane is a sustainable energy that is produced from an organic and renewable resource. As the second-largest oil palm producer in the world, palm oil mill effluent (POME) is the primary source of biomethane generation in Malaysia. POME is the by-product of palm oil extraction and is extensively employed as a feedstock for the production of biomethane. Malaysia has an equatorial environment with humid and hot weather; this climate is conducive to the cultivation of numerous agricultural crops. A considerable number of agricultural wastes and residues are produced by agricultural crops, however, only 27% of them are used as fuel or to create useable products. Several publications have been published on the production of biomethane from POME; nevertheless, additional research is required on the use of other bioresources and technologies for biomethane production in Malaysia. In addition, there is a lack of comprehensive information on the future development of biomethane production in Malaysia; thus, to fill this gap, this review paper focuses on the challenges and future of Malaysia, which puts an emphasis on POME and also includes other alternative options of bioresources that can be the future feedstock for biomethane production in Malaysia. To the best of our knowledge, this is the first paper to provide a comprehensive overview of the biogas trend in Malaysia in terms of challenges and current biomethane development, as well as detailed information on a number of leading companies that are currently active in Malaysia biogas industry.
{"title":"Methane Biogas Production in Malaysia: Challenge and Future Plan","authors":"Muhd Arshad Amin, H. Shukor, L. Yin, F. Kasim, N. F. Shoparwe, M. Z. Makhtar, A. Yaser","doi":"10.1155/2022/2278211","DOIUrl":"https://doi.org/10.1155/2022/2278211","url":null,"abstract":"Biomethane is a sustainable energy that is produced from an organic and renewable resource. As the second-largest oil palm producer in the world, palm oil mill effluent (POME) is the primary source of biomethane generation in Malaysia. POME is the by-product of palm oil extraction and is extensively employed as a feedstock for the production of biomethane. Malaysia has an equatorial environment with humid and hot weather; this climate is conducive to the cultivation of numerous agricultural crops. A considerable number of agricultural wastes and residues are produced by agricultural crops, however, only 27% of them are used as fuel or to create useable products. Several publications have been published on the production of biomethane from POME; nevertheless, additional research is required on the use of other bioresources and technologies for biomethane production in Malaysia. In addition, there is a lack of comprehensive information on the future development of biomethane production in Malaysia; thus, to fill this gap, this review paper focuses on the challenges and future of Malaysia, which puts an emphasis on POME and also includes other alternative options of bioresources that can be the future feedstock for biomethane production in Malaysia. To the best of our knowledge, this is the first paper to provide a comprehensive overview of the biogas trend in Malaysia in terms of challenges and current biomethane development, as well as detailed information on a number of leading companies that are currently active in Malaysia biogas industry.","PeriodicalId":13921,"journal":{"name":"International Journal of Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49203151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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