Hong Jiang, Qingsong Liu, Ling Zhou, Penggang Zhang, Peng Gao, Chen Xiao, Donglei Yang
Recovering ethane from natural gas involves significant energy consumption. Globally, the recycle split vapor process (RSV) is widely adopted as an efficient method for ethane recovery. Nonetheless, one major challenge faced by the RSV process is the lack of adequate heat integration, despite its overall effectiveness. In this article, we investigate the heat integration of the RSV process and propose two novel ethane recovery processes: the recycle split vapor process with direct heat integration of the feed gas (RSV‐DTI) and the recycle split vapor process with split heat integration of the feed gas (RSV‐SHI). A comparative analysis is conducted among these three processes, focusing on integrated energy consumption, exergy efficiency, and economic investment. The study's findings reveal the following: (1) The RSV‐DTI process distinguishes itself with its reduced energy consumption, enhanced stability, and minimized refrigerant usage. In comparison to the RSV process, the RSV‐DTI process achieves a reduction of over 15% in total compression duty and a remarkable decrease of 68% in propane usage. (2) Electricity emerges as the predominant energy consumed in the ethane recovery process, and the RSV‐DTI process significantly improves upon this aspect. Notably, the RSV‐DTI process incurs the lowest investment cost, yielding a swift payback period of approximately 1 year for the plant. The characteristics of the RSV‐DTI process are investigated, and the effect of changes in feed gas conditions on the heat integration of the RSV‐DTI process is analyzed. The characteristics of the RSV‐DTI process show the following: (1) Different pressures of feed gas existing in the main cold box have different minimum heat integration temperatures (MHIT). When the feed gas temperature is lower than the MHIT, heat integration becomes difficult, and the heat energy can be supplied by hot liquid propane at 48°C. When the feed gas temperature is higher than the MHIT, changes in feed gas temperature have little effect on the process, only affecting the external gas temperature. (2) The heat transfer duty of the demethanizer sideline outlet stream is affected by the feed gas pressure. To enhance heat integration, it is recommended to set the heat transfer duty of the low‐temperature sideline outlet stream (DLTSS) between 40% and 90% of the reboiler duty and the heat transfer duty of the high‐temperature sideline outlet stream (DHTSS) between 40% and 75% of the reboiler duty.
{"title":"Heat integration analysis based on recycle split vapor ethane recovery process","authors":"Hong Jiang, Qingsong Liu, Ling Zhou, Penggang Zhang, Peng Gao, Chen Xiao, Donglei Yang","doi":"10.1002/apj.3107","DOIUrl":"https://doi.org/10.1002/apj.3107","url":null,"abstract":"Recovering ethane from natural gas involves significant energy consumption. Globally, the recycle split vapor process (RSV) is widely adopted as an efficient method for ethane recovery. Nonetheless, one major challenge faced by the RSV process is the lack of adequate heat integration, despite its overall effectiveness. In this article, we investigate the heat integration of the RSV process and propose two novel ethane recovery processes: the recycle split vapor process with direct heat integration of the feed gas (RSV‐DTI) and the recycle split vapor process with split heat integration of the feed gas (RSV‐SHI). A comparative analysis is conducted among these three processes, focusing on integrated energy consumption, exergy efficiency, and economic investment. The study's findings reveal the following: (1) The RSV‐DTI process distinguishes itself with its reduced energy consumption, enhanced stability, and minimized refrigerant usage. In comparison to the RSV process, the RSV‐DTI process achieves a reduction of over 15% in total compression duty and a remarkable decrease of 68% in propane usage. (2) Electricity emerges as the predominant energy consumed in the ethane recovery process, and the RSV‐DTI process significantly improves upon this aspect. Notably, the RSV‐DTI process incurs the lowest investment cost, yielding a swift payback period of approximately 1 year for the plant. The characteristics of the RSV‐DTI process are investigated, and the effect of changes in feed gas conditions on the heat integration of the RSV‐DTI process is analyzed. The characteristics of the RSV‐DTI process show the following: (1) Different pressures of feed gas existing in the main cold box have different minimum heat integration temperatures (MHIT). When the feed gas temperature is lower than the MHIT, heat integration becomes difficult, and the heat energy can be supplied by hot liquid propane at 48°C. When the feed gas temperature is higher than the MHIT, changes in feed gas temperature have little effect on the process, only affecting the external gas temperature. (2) The heat transfer duty of the demethanizer sideline outlet stream is affected by the feed gas pressure. To enhance heat integration, it is recommended to set the heat transfer duty of the low‐temperature sideline outlet stream (DLTSS) between 40% and 90% of the reboiler duty and the heat transfer duty of the high‐temperature sideline outlet stream (DHTSS) between 40% and 75% of the reboiler duty.","PeriodicalId":8852,"journal":{"name":"Asia-Pacific Journal of Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141194795","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}
Xiangsen Shao, Chenliang Peng, Guanshi Wang, Lei Qin, Ping Long
The adsorption behavior of NH4+ and Mg2+ at kaolinite surfaces was investigated by using molecular dynamics (MD) simulations, considering the factors such as ion concentration, NH4+/Mg2+ mixing ratio, and layer charge of kaolinite. The results showed that the increase in ion concentration did not affect the adsorption modes of NH4+ and Mg2+ ions but promote the increase in the adsorption capacity. The total adsorption capacities of Mg2+ and NH4+ were 3.25 × 10−6 and 2.85 × 10−6 μmol·mm−2 at the ion concentration of 1.5 mol·L−1, respectively. When NH4+ and Mg2+ were co-adsorbed, they could inhibit the adsorption of each other at the surface of kaolinite, except that the inner-sphere (IS) adsorption of NH4+ at aluminum hydroxyl (Al–OH) surface could be enhanced by the presence of Mg2+. Both NH4+ and Mg2+ tended to adsorb at the siloxane (Si–O) surface of kaolinite rather than Al–OH surface. When layer charge occurred in kaolinite, a small number of Mg2+ began to adsorb in the IS complexes at 1.7 and 2.3 Å above the Al and O atoms of the lattice-substituted tetrahedra of the Si–O surface, and at 1.7 Å above the hexahedra of the Al–OH surface. However, most of NH4+ were adsorbed in IS complexes at 1.7 Å above the center of the oxygen six-membered ring of the Si–O surface and above the hexahedron of the Al–OH surface. The adsorption capacity of Mg2+ changed little with the increase of layer charge density, while the IS and total adsorption capacity of NH4+ increased significantly.
利用分子动力学（MD）模拟研究了NH4+和Mg2+在高岭石表面的吸附行为，考虑了离子浓度、NH4+/Mg2+混合比和高岭石层电荷等因素。结果表明，离子浓度的增加并不影响 NH4+ 和 Mg2+ 离子的吸附模式，但会促进吸附容量的增加。在离子浓度为 1.5 mol-L-1 时，Mg2+ 和 NH4+ 的总吸附容量分别为 3.25 × 10-6 和 2.85 × 10-6 μmol-m-2。当 NH4+ 和 Mg2+ 共吸附时，它们在高岭石表面的吸附相互抑制，但 Mg2+ 的存在可增强 NH4+ 在羟基铝（Al-OH）表面的内球吸附。NH4+ 和 Mg2+ 都倾向于吸附在高岭石的硅氧烷（Si-O）表面，而不是 Al-OH 表面。当高岭石中出现层电荷时，IS 复合物中的少量 Mg2+ 开始吸附在 Si-O 表面晶格取代四面体的 Al 原子和 O 原子上方 1.7 Å 和 2.3 Å 处，以及 Al-OH 表面六面体上方 1.7 Å 处。然而，大部分 NH4+ 被吸附在 Si-O 表面氧六元环中心上方 1.7 Å 和 Al-OH 表面六面体上方的 IS 复合物中。随着层电荷密度的增加，Mg2+ 的吸附容量变化不大，而 NH4+ 的 IS 和总吸附容量则显著增加。
{"title":"Adsorption behavior of NH4+ and Mg2+ at kaolinite surfaces: Effect of the ion concentration, NH4+/Mg2+ mixing ratio, and layer charge","authors":"Xiangsen Shao, Chenliang Peng, Guanshi Wang, Lei Qin, Ping Long","doi":"10.1002/apj.3106","DOIUrl":"https://doi.org/10.1002/apj.3106","url":null,"abstract":"The adsorption behavior of NH<sub>4</sub><sup>+</sup> and Mg<sup>2+</sup> at kaolinite surfaces was investigated by using molecular dynamics (MD) simulations, considering the factors such as ion concentration, NH<sub>4</sub><sup>+</sup>/Mg<sup>2+</sup> mixing ratio, and layer charge of kaolinite. The results showed that the increase in ion concentration did not affect the adsorption modes of NH<sub>4</sub><sup>+</sup> and Mg<sup>2+</sup> ions but promote the increase in the adsorption capacity. The total adsorption capacities of Mg<sup>2+</sup> and NH<sub>4</sub><sup>+</sup> were 3.25 × 10<sup>−6</sup> and 2.85 × 10<sup>−6</sup> μmol·mm<sup>−2</sup> at the ion concentration of 1.5 mol·L<sup>−1</sup>, respectively. When NH<sub>4</sub><sup>+</sup> and Mg<sup>2+</sup> were co-adsorbed, they could inhibit the adsorption of each other at the surface of kaolinite, except that the inner-sphere (IS) adsorption of NH<sub>4</sub><sup>+</sup> at aluminum hydroxyl (Al–OH) surface could be enhanced by the presence of Mg<sup>2+</sup>. Both NH<sub>4</sub><sup>+</sup> and Mg<sup>2+</sup> tended to adsorb at the siloxane (Si–O) surface of kaolinite rather than Al–OH surface. When layer charge occurred in kaolinite, a small number of Mg<sup>2+</sup> began to adsorb in the IS complexes at 1.7 and 2.3 Å above the Al and O atoms of the lattice-substituted tetrahedra of the Si–O surface, and at 1.7 Å above the hexahedra of the Al–OH surface. However, most of NH<sub>4</sub><sup>+</sup> were adsorbed in IS complexes at 1.7 Å above the center of the oxygen six-membered ring of the Si–O surface and above the hexahedron of the Al–OH surface. The adsorption capacity of Mg<sup>2+</sup> changed little with the increase of layer charge density, while the IS and total adsorption capacity of NH<sub>4</sub><sup>+</sup> increased significantly.","PeriodicalId":8852,"journal":{"name":"Asia-Pacific Journal of Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141171528","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}
Vadim A. Eremin, Maxim V. Ananyev, Anton A. Solodyankin, Alexander A. Markin
This paper focuses on long‐term tests held during 1,000 h on different Membrane‐Electrode‐Interconnect Assemblies (MEIAs), consisting of an Fe‐Ni alloy interconnect and an electrochemical cell based on a Ce0.8Sm0.2O2–δ electrolyte, the double‐layer working electrode with a La2NiO4 + δ – Ce0.8Sm0.2O2–δ composite functional layer, and a LaNi0.6Fe0.4O3–δ current collector layer, and a platinum reference electrode (O2, LaNi0.6Fe0.4O3–δ|La2NiO4 + δ – Ce0.8Sm0.2O2–δ|Ce0.8Sm0.2O2–δ|Pt, O2). These tests were carried out on MEIAs with the Cr‐free 47ND alloy of the Fe–Ni system with and without surface modification at 850°C in air. The electrochemical performance of MEIAs was studied without polarization as well as under cathodic and anodic polarization with current density 0.5 A cm−2 by means of electrochemical impedance spectroscopy (EIS). The mechanism of the MEIA evolution during long‐term test is discussed.
{"title":"Degradation of iron‐nickel alloy interconnects in contact with lanthanum nickelates based double‐layer electrodes during long‐term tests","authors":"Vadim A. Eremin, Maxim V. Ananyev, Anton A. Solodyankin, Alexander A. Markin","doi":"10.1002/apj.3091","DOIUrl":"https://doi.org/10.1002/apj.3091","url":null,"abstract":"This paper focuses on long‐term tests held during 1,000 h on different Membrane‐Electrode‐Interconnect Assemblies (MEIAs), consisting of an Fe‐Ni alloy interconnect and an electrochemical cell based on a Ce<jats:sub>0.8</jats:sub>Sm<jats:sub>0.2</jats:sub>O<jats:sub>2–δ</jats:sub> electrolyte, the double‐layer working electrode with a La<jats:sub>2</jats:sub>NiO<jats:sub>4 + δ</jats:sub> – Ce<jats:sub>0.8</jats:sub>Sm<jats:sub>0.2</jats:sub>O<jats:sub>2–δ</jats:sub> composite functional layer, and a LaNi<jats:sub>0.6</jats:sub>Fe<jats:sub>0.4</jats:sub>O<jats:sub>3–δ</jats:sub> current collector layer, and a platinum reference electrode (O<jats:sub>2</jats:sub>, LaNi<jats:sub>0.6</jats:sub>Fe<jats:sub>0.4</jats:sub>O<jats:sub>3–δ</jats:sub>|La<jats:sub>2</jats:sub>NiO<jats:sub>4 + δ</jats:sub> – Ce<jats:sub>0.8</jats:sub>Sm<jats:sub>0.2</jats:sub>O<jats:sub>2–δ</jats:sub>|Ce<jats:sub>0.8</jats:sub>Sm<jats:sub>0.2</jats:sub>O<jats:sub>2–δ</jats:sub>|Pt, O<jats:sub>2</jats:sub>). These tests were carried out on MEIAs with the Cr‐free 47ND alloy of the Fe–Ni system with and without surface modification at 850°C in air. The electrochemical performance of MEIAs was studied without polarization as well as under cathodic and anodic polarization with current density 0.5 A cm<jats:sup>−2</jats:sup> by means of electrochemical impedance spectroscopy (EIS). The mechanism of the MEIA evolution during long‐term test is discussed.","PeriodicalId":8852,"journal":{"name":"Asia-Pacific Journal of Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141063337","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}
Shaocheng Pan, Maoliang Li, Weicheng Li, Xiaolong Lin, Yinhe Liu
Lignite‐fired boilers usually encounter the insufficient drying capacity of the pulverizer due to the inherent drawback of high moisture content in fuel. In this study, four schemes of heat sources for temperature boosting of hot primary air are proposed for an ultra‐supercritical large‐scale single reheat lignite‐fired power plant according to heat sources such as inlet flue gas of air preheater (Scheme 1), the third stage extraction steam (Scheme 2), outlet steam of low‐temperature reheater (Scheme 3), and inlet flue gas of economizer (Scheme 4). The thermodynamic system models are built by using EBSILON Professional software. The thermodynamic performance of the four schemes is analyzed and compared from the perspectives of the first and second laws of thermodynamics. First law analysis indicates that the power generation standard coal consumption of Scheme 3 is reduced by 0.87, 0.42, and 0.04 g·kW−1·h−1 compared with Schemes 1, 2, and 4, respectively. Second law analysis indicates that the exergy loss of Schemes 2–4 is 3.7, 7.6, and 7.5 MW lower than that of Scheme 1. The present study may provide guidance for the energy efficiency improvement of lignite‐fired power plants.
{"title":"Thermodynamic analysis of temperature boosting of hot primary air in an ultra‐supercritical lignite‐fired power plant: Scheme comparison and performance enhancement","authors":"Shaocheng Pan, Maoliang Li, Weicheng Li, Xiaolong Lin, Yinhe Liu","doi":"10.1002/apj.3093","DOIUrl":"https://doi.org/10.1002/apj.3093","url":null,"abstract":"Lignite‐fired boilers usually encounter the insufficient drying capacity of the pulverizer due to the inherent drawback of high moisture content in fuel. In this study, four schemes of heat sources for temperature boosting of hot primary air are proposed for an ultra‐supercritical large‐scale single reheat lignite‐fired power plant according to heat sources such as inlet flue gas of air preheater (Scheme 1), the third stage extraction steam (Scheme 2), outlet steam of low‐temperature reheater (Scheme 3), and inlet flue gas of economizer (Scheme 4). The thermodynamic system models are built by using EBSILON Professional software. The thermodynamic performance of the four schemes is analyzed and compared from the perspectives of the first and second laws of thermodynamics. First law analysis indicates that the power generation standard coal consumption of Scheme 3 is reduced by 0.87, 0.42, and 0.04 g·kW−1·h−1 compared with Schemes 1, 2, and 4, respectively. Second law analysis indicates that the exergy loss of Schemes 2–4 is 3.7, 7.6, and 7.5 MW lower than that of Scheme 1. The present study may provide guidance for the energy efficiency improvement of lignite‐fired power plants.","PeriodicalId":8852,"journal":{"name":"Asia-Pacific Journal of Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140966079","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}
Qiu-li Zhang, Jun Yi Li, Hai Xuan Wang, Jun Li Liu, Jun Zhou
This study explores the low‐temperature pyrolysis kinetic of low metamorphic grade coal from Northern Shaanxi, utilizing Fourier transform infrared (FT‐IR) spectroscopy to analyze the characteristics of various functional groups over a 293–1023 K temperature range. A kinetic model, correlating with the pyrolysis behaviors of these groups, was developed through thermal analysis kinetics. Computational fluid dynamics (CFD) technology simulated the furnace's flow dynamics, allowing an examination of the physical field alterations and functional group evolution during pyrolysis. Results showed that the pyrolysis kinetic functions for aromatic C–H, C=C, C–O, and •OH, along with temperature, pressure, and velocity fields, were successfully integrated into the simulation. This integration provided detailed insights into the temperature profile, pressure distribution, flow velocities, and functional group distribution in the furnace. Aliphatics, exhibiting the largest mass fraction and wide pyrolysis temperature range, and •OH radicals with the highest activation energy were concentrated in the furnace's pyrolysis zone center. C=C's distribution was influenced by aromatic C–H and aliphatics, showing a complementary pattern. The oxygen‐containing groups C–O and C=O had similar pyrolysis mechanisms and uniform distribution. The functional groups' mass fractions were ranked from highest to lowest as follows: aliphatics > •OH > aromatic C–H > C–O > C=C > C=O.
{"title":"Kinetics of pyrolysis and Computational Fluid Dynamics modeling of low metamorphic coal","authors":"Qiu-li Zhang, Jun Yi Li, Hai Xuan Wang, Jun Li Liu, Jun Zhou","doi":"10.1002/apj.3095","DOIUrl":"https://doi.org/10.1002/apj.3095","url":null,"abstract":"This study explores the low‐temperature pyrolysis kinetic of low metamorphic grade coal from Northern Shaanxi, utilizing Fourier transform infrared (FT‐IR) spectroscopy to analyze the characteristics of various functional groups over a 293–1023 K temperature range. A kinetic model, correlating with the pyrolysis behaviors of these groups, was developed through thermal analysis kinetics. Computational fluid dynamics (CFD) technology simulated the furnace's flow dynamics, allowing an examination of the physical field alterations and functional group evolution during pyrolysis. Results showed that the pyrolysis kinetic functions for aromatic C–H, C=C, C–O, and •OH, along with temperature, pressure, and velocity fields, were successfully integrated into the simulation. This integration provided detailed insights into the temperature profile, pressure distribution, flow velocities, and functional group distribution in the furnace. Aliphatics, exhibiting the largest mass fraction and wide pyrolysis temperature range, and •OH radicals with the highest activation energy were concentrated in the furnace's pyrolysis zone center. C=C's distribution was influenced by aromatic C–H and aliphatics, showing a complementary pattern. The oxygen‐containing groups C–O and C=O had similar pyrolysis mechanisms and uniform distribution. The functional groups' mass fractions were ranked from highest to lowest as follows: aliphatics > •OH > aromatic C–H > C–O > C=C > C=O.","PeriodicalId":8852,"journal":{"name":"Asia-Pacific Journal of Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140964151","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}
Haopeng Wang, Shanshan Deng, Shuguang Ti, Haoze Jin, Zhi Yang, Ke Gao, Xuehong Wu, Shengyong Liu, Jingxue An, Ranran Sheng
To enhance the rapid switching ability of the boiler load and reduce NOx emissions, a new combustion system was implemented in a 600‐MWe wall‐fired boiler with swirl burners. This system included two levels of overfire air (OFA) and low NOx combustion technology. Industrial tests were conducted at 300‐, 450‐, and 600‐MWe loads before and after the retrofitted. These tests included measuring flue gas and furnace temperatures with thermocouples and analyzing local gas concentrations using a gas analyzer. The research results indicate that under conditions where the OFA ratio exceeds 30%, the burner exhibits good ignition performance at different loads. At the 600‐MWe load, the nitrogen oxides (NOx) emissions were reduced by 55% compared to before the retrofit. After the retrofit, the flame center inside the furnace of different loads was located at the height of 33.36 m, the first and second‐stage cooling water quantities were slightly higher, the reheat cooling water quantity was greatly reduced after the retrofit, and contributes to the boiler's safe operation. Under different load conditions after the retrofit, the gas temperature near the sidewall was below 850°C, and the O2 concentration near the sidewall was above 5%, effectively suppressing sidewall high‐temperature corrosion and slagging.
{"title":"Experimental combustion characteristics and NOx emissions for a 600‐MWe utility boiler after the retrofitted: Effects of load variation","authors":"Haopeng Wang, Shanshan Deng, Shuguang Ti, Haoze Jin, Zhi Yang, Ke Gao, Xuehong Wu, Shengyong Liu, Jingxue An, Ranran Sheng","doi":"10.1002/apj.3092","DOIUrl":"https://doi.org/10.1002/apj.3092","url":null,"abstract":"To enhance the rapid switching ability of the boiler load and reduce NOx emissions, a new combustion system was implemented in a 600‐MWe wall‐fired boiler with swirl burners. This system included two levels of overfire air (OFA) and low NOx combustion technology. Industrial tests were conducted at 300‐, 450‐, and 600‐MWe loads before and after the retrofitted. These tests included measuring flue gas and furnace temperatures with thermocouples and analyzing local gas concentrations using a gas analyzer. The research results indicate that under conditions where the OFA ratio exceeds 30%, the burner exhibits good ignition performance at different loads. At the 600‐MWe load, the nitrogen oxides (NOx) emissions were reduced by 55% compared to before the retrofit. After the retrofit, the flame center inside the furnace of different loads was located at the height of 33.36 m, the first and second‐stage cooling water quantities were slightly higher, the reheat cooling water quantity was greatly reduced after the retrofit, and contributes to the boiler's safe operation. Under different load conditions after the retrofit, the gas temperature near the sidewall was below 850°C, and the O2 concentration near the sidewall was above 5%, effectively suppressing sidewall high‐temperature corrosion and slagging.","PeriodicalId":8852,"journal":{"name":"Asia-Pacific Journal of Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140971717","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}
K. Ahmad, S. Jaffri, Bhumikaben Makawana, Ram K. Gupta, G. A. Ashraf, Nouf H. Alotaibi
Due to its potential uses, including e‐vehicles, electrochemical energy storage has attracted a lot of interest from the scientific community and energy stakeholders. With the usage of the novel semiconductor chalcogenide BaS3:Cu2S:Mn2S, which is synthesized by chelating with diethyldithiocarbamate ligand, the current work seeks to enhance the performance of charge‐storage devices. An energy band gap of 2.57 eV was found for this semiconductor, which showed remarkable photoactivity. The chalcogenide that was produced had favorable crystallinity, with an average crystallite size of 26.92 nm and mixed crystalline phases. Additionally, metallic sulfide linkages were identified using infrared spectroscopy, and they were reported to range from 400 to 845 cm−1. Thermal breakdown in two steps was verified using thermogravimetric analysis. Particles with different forms and a rod‐like fusion suggested a higher volume–surface area ratio and many locations. The electrochemical performance of the BaS3:Cu2S:Mn2S was evaluated using a traditional three‐electrode setup with a background electrolyte of 1‐M KOH. BaS3:Cu2S:Mn2S is a great electrode material for energy storage applications, with a specific power density of 10 618 W kg−1 and a specific capacitance of up to 694 F g−1. The same series resistance (Rs) = 0.46 Ω further supported this remarkable electrochemical performance.
{"title":"Supercapacitor performance enhancement with the BaS3:Cu2S:Mn2S trichalcogenide semiconductor synthesized via dithiocarbamate precursors","authors":"K. Ahmad, S. Jaffri, Bhumikaben Makawana, Ram K. Gupta, G. A. Ashraf, Nouf H. Alotaibi","doi":"10.1002/apj.3096","DOIUrl":"https://doi.org/10.1002/apj.3096","url":null,"abstract":"Due to its potential uses, including e‐vehicles, electrochemical energy storage has attracted a lot of interest from the scientific community and energy stakeholders. With the usage of the novel semiconductor chalcogenide BaS3:Cu2S:Mn2S, which is synthesized by chelating with diethyldithiocarbamate ligand, the current work seeks to enhance the performance of charge‐storage devices. An energy band gap of 2.57 eV was found for this semiconductor, which showed remarkable photoactivity. The chalcogenide that was produced had favorable crystallinity, with an average crystallite size of 26.92 nm and mixed crystalline phases. Additionally, metallic sulfide linkages were identified using infrared spectroscopy, and they were reported to range from 400 to 845 cm−1. Thermal breakdown in two steps was verified using thermogravimetric analysis. Particles with different forms and a rod‐like fusion suggested a higher volume–surface area ratio and many locations. The electrochemical performance of the BaS3:Cu2S:Mn2S was evaluated using a traditional three‐electrode setup with a background electrolyte of 1‐M KOH. BaS3:Cu2S:Mn2S is a great electrode material for energy storage applications, with a specific power density of 10 618 W kg−1 and a specific capacitance of up to 694 F g−1. The same series resistance (Rs) = 0.46 Ω further supported this remarkable electrochemical performance.","PeriodicalId":8852,"journal":{"name":"Asia-Pacific Journal of Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140977429","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}
Jing Zhang, Zhexuan Jiang, Wenhao Hou, Aibo Jian, Yaxia Li, Zhiguo Tian, Bin Gong
This study combined numerical simulation and experiment to explore the influence of the concave‐wall jets with uniformly distributed tangential inlets in the cyclone separator on the liquid–solid separation characteristics and equipment. The results show that as the number of tangential inlets increases, the superposition effect of particle trajectories and flow fields becomes more significant. The superimposed flow field enhances the circumferential flow velocity of the fluid, causing the distribution of the jet along the radial and spanwise directions to shrink, greatly improving the uniformity of particle distribution and turbulent kinetic energy along the circumference, and effectively reducing the impact of particles on local areas near the jet inlet. Since the superposition of circumferential multi‐inlet jets enhances the swirling flow, the local disturbance and wall erosion effects near the jet inlet were reduced. Compared with double inlets, the flow rates of three inlets and four inlets were increased by 50% and 100%, respectively, the maximum turbulent kinetic energy increased by 14.5% and 56.2%, and the maximum escape time of particles was shortened by 3.2 and 3.3 s, respectively, the maximum erosion rates were reduced by 38.4% and 23.6%, respectively, and the separation efficiency and material handling capacity were significantly improved. This study supplemented the theory of concave‐wall jets' superposition characteristics and provided a theoretical basis for applying circumferential multi‐inlet devices in liquid–solid separation equipment.
{"title":"Effect of concave‐wall jets with circumferential multi‐inlet on liquid–solid separation","authors":"Jing Zhang, Zhexuan Jiang, Wenhao Hou, Aibo Jian, Yaxia Li, Zhiguo Tian, Bin Gong","doi":"10.1002/apj.3090","DOIUrl":"https://doi.org/10.1002/apj.3090","url":null,"abstract":"This study combined numerical simulation and experiment to explore the influence of the concave‐wall jets with uniformly distributed tangential inlets in the cyclone separator on the liquid–solid separation characteristics and equipment. The results show that as the number of tangential inlets increases, the superposition effect of particle trajectories and flow fields becomes more significant. The superimposed flow field enhances the circumferential flow velocity of the fluid, causing the distribution of the jet along the radial and spanwise directions to shrink, greatly improving the uniformity of particle distribution and turbulent kinetic energy along the circumference, and effectively reducing the impact of particles on local areas near the jet inlet. Since the superposition of circumferential multi‐inlet jets enhances the swirling flow, the local disturbance and wall erosion effects near the jet inlet were reduced. Compared with double inlets, the flow rates of three inlets and four inlets were increased by 50% and 100%, respectively, the maximum turbulent kinetic energy increased by 14.5% and 56.2%, and the maximum escape time of particles was shortened by 3.2 and 3.3 s, respectively, the maximum erosion rates were reduced by 38.4% and 23.6%, respectively, and the separation efficiency and material handling capacity were significantly improved. This study supplemented the theory of concave‐wall jets' superposition characteristics and provided a theoretical basis for applying circumferential multi‐inlet devices in liquid–solid separation equipment.","PeriodicalId":8852,"journal":{"name":"Asia-Pacific Journal of Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140980905","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}
Deepshikha Datta, Sampurna Santra, Sayantan Sarkar, Bimal Das
Starch blended low-density polyethylene (LDPE) has been extensively used to produce packaging film, but it has very low mechanical properties. This work emphasises the extraction of nanosilica from rice husk as a property-enhancing filler for producing high-quality packaging material. Nanosilica (200 nm) was obtained by chemical treatment followed by further size reduction through cryomill. The obtained nanomaterial was found to have a high surface area (189.64 m2/g) and pore volume (.462 cc/g) with high compatibility with the other materials in the matrix. The SEM and TEM analysis indicates the uniformity in particle size of the nanomaterial with an agglomerating tendency. The X-ray diffractometer (XRD) and fourier transform infrared spectroscopy (FTIR) analysis reveals that the obtained material is amorphous in nature. The nanomaterial is dispersed in various proportions in LDPE/starch matrix, and it is observed that the highest tensile strength (9.62 MPa) can be obtained at 1.5% nanosilica content in the matrix. A continuous increase in Young's modulus and stiffness from 372.3 to 440.12 MPa and 20 243.2 to 28 559.42 N/m, respectively, when 1.5% of nanosilica is dispersed in the biodegradable matrix. Garden soil was a better degrading medium for the sample containing 20% of starch with weight loss of 10.32% and reduction of tensile strength and tear strength values to 5.987 MPa and 99.165 N/mm respectively, in 1 year.
{"title":"Role of extracted nanosilica from rice husk on the structure, property and biodegradability of low density polyethylene/starch biodegradable film","authors":"Deepshikha Datta, Sampurna Santra, Sayantan Sarkar, Bimal Das","doi":"10.1002/apj.3087","DOIUrl":"https://doi.org/10.1002/apj.3087","url":null,"abstract":"Starch blended low-density polyethylene (LDPE) has been extensively used to produce packaging film, but it has very low mechanical properties. This work emphasises the extraction of nanosilica from rice husk as a property-enhancing filler for producing high-quality packaging material. Nanosilica (200 nm) was obtained by chemical treatment followed by further size reduction through cryomill. The obtained nanomaterial was found to have a high surface area (189.64 m<sup>2</sup>/g) and pore volume (.462 cc/g) with high compatibility with the other materials in the matrix. The SEM and TEM analysis indicates the uniformity in particle size of the nanomaterial with an agglomerating tendency. The X-ray diffractometer (XRD) and fourier transform infrared spectroscopy (FTIR) analysis reveals that the obtained material is amorphous in nature. The nanomaterial is dispersed in various proportions in LDPE/starch matrix, and it is observed that the highest tensile strength (9.62 MPa) can be obtained at 1.5% nanosilica content in the matrix. A continuous increase in Young's modulus and stiffness from 372.3 to 440.12 MPa and 20 243.2 to 28 559.42 N/m, respectively, when 1.5% of nanosilica is dispersed in the biodegradable matrix. Garden soil was a better degrading medium for the sample containing 20% of starch with weight loss of 10.32% and reduction of tensile strength and tear strength values to 5.987 MPa and 99.165 N/mm respectively, in 1 year.","PeriodicalId":8852,"journal":{"name":"Asia-Pacific Journal of Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140886413","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}
Xia Lu, Xiuqing Lu, Kai Yang, Xiaotao Zheng, Shixian Wang
The influence of circulating liquid velocity on bubble size distribution (BSD) and turbulence characteristics of an external loop airlift reactor was studied in this paper. The instantaneous and time‐averaged velocity in the riser were studied using particle image velocimetry (PIV), and BSDs were measured by digital image analysis technique based on machine learning. Then turbulence kinetic energy (TKE) and energy dissipation rate (EDR) were calculated through the velocity field. The results indicate that as the circulating liquid velocity increased, the peak value of BSD rapidly decreased from nearly 6 mm to approximately 2 mm. The radial velocity of the liquid gradually decreased and changed direction, eventually increasing again. TKE first decreased and then increased. Compared with bubble flow with a BSD peak of 2–6 mm, bubble flow with a BSD peak of 2 mm had larger TKE. The radial movement of bubbles had great influence on the turbulence characteristics. This study demonstrates that selecting an appropriate circulating liquid velocity can reduce the diameter of bubbles while obtaining greater TKE, thereby improving the mass transfer and reaction efficiency in external loop airlift reactors (EL‐ALR).
本文研究了循环液体速度对外循环气举反应器气泡尺寸分布（BSD）和湍流特性的影响。利用粒子图像测速仪（PIV）研究了立管中的瞬时速度和时间平均速度，并利用基于机器学习的数字图像分析技术测量了 BSD。然后通过速度场计算湍流动能（TKE）和能量耗散率（EDR）。结果表明，随着循环液体速度的增加，BSD 的峰值从近 6 mm 快速下降到约 2 mm。液体的径向速度逐渐减小并改变方向，最终再次增大。TKE 先减小后增大。与 BSD 峰值为 2-6 mm 的气泡流相比，BSD 峰值为 2 mm 的气泡流的 TKE 更大。气泡的径向运动对湍流特性有很大影响。这项研究表明，选择适当的循环液速可以减小气泡直径，同时获得更大的 TKE，从而提高外循环气提反应器（EL-ALR）的传质和反应效率。
{"title":"Experimental study on the effect of circulating liquid velocity on bubble size distribution and turbulence characteristic in an external loop airlift reactor","authors":"Xia Lu, Xiuqing Lu, Kai Yang, Xiaotao Zheng, Shixian Wang","doi":"10.1002/apj.3083","DOIUrl":"https://doi.org/10.1002/apj.3083","url":null,"abstract":"The influence of circulating liquid velocity on bubble size distribution (BSD) and turbulence characteristics of an external loop airlift reactor was studied in this paper. The instantaneous and time‐averaged velocity in the riser were studied using particle image velocimetry (PIV), and BSDs were measured by digital image analysis technique based on machine learning. Then turbulence kinetic energy (TKE) and energy dissipation rate (EDR) were calculated through the velocity field. The results indicate that as the circulating liquid velocity increased, the peak value of BSD rapidly decreased from nearly 6 mm to approximately 2 mm. The radial velocity of the liquid gradually decreased and changed direction, eventually increasing again. TKE first decreased and then increased. Compared with bubble flow with a BSD peak of 2–6 mm, bubble flow with a BSD peak of 2 mm had larger TKE. The radial movement of bubbles had great influence on the turbulence characteristics. This study demonstrates that selecting an appropriate circulating liquid velocity can reduce the diameter of bubbles while obtaining greater TKE, thereby improving the mass transfer and reaction efficiency in external loop airlift reactors (EL‐ALR).","PeriodicalId":8852,"journal":{"name":"Asia-Pacific Journal of Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140826993","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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