Impact of Thermal Asymmetry on Efficiency of the Heat Recovery and Ways of Restoring Symmetry in the Flow Reversal Reactors

2018 ◽  
Vol 17 (3) ◽  
Author(s):  
Krzysztof Gosiewski ◽  
Anna Pawlaczyk-Kurek
Keyword(s):  
Heat Recovery ◽  
Flow Reactor ◽  
Reverse Flow ◽  
Computer Control ◽  
Point Of View ◽  
Flow Reversal ◽  
Recovery Efficiency ◽  
Process Data ◽  
Exchange Unit ◽  
The Impact

Abstract The problem discussed in the paper was revealed during experimental and simulation study of the waste fuel utilization (low concentrated CH4) which in coal mines is emitted to the atmosphere as the so-called ventilation air methane (abbreviation: VAM). When an intense heat recovery would be applied to the Reverse-Flow Reactor (RFR) then the reactor becomes susceptible to creation of temperature profiles asymmetry. This may adversely affects the heat recovery efficiency. When a strong asymmetry arises, it can significantly reduce the heat recovery and the system needs immediate counteraction. Commonly used control systems do not always cope with this problem. The paper discusses various RFRs control algorithms from the point of view of the ability to reduce symmetry to the acceptable range. The impact of the loss of reactor symmetry on possible heat recovery efficiency is also briefly discussed. The work is focused on RFRs which operate with significant heat recovery in a heat exchange unit in which heat is retrieved not at the rector outlet, but by cooling the hot gas from the center part of the reactor. Issues discussed in the paper are derived from being carried out in ICE-PAS through many years of simulation research, patent examinations, but primarily from the own experiences on the research & demonstration thermal flow reversal reactor (TFRR) for VAM combustion. Computer control & data recording system process data records of the experiments enabled effectively analyze the problem of creating and preventing thermal asymmetry.

scholarly journals Analyzing the Impact of the Phius HRV/ERV protocol on North American Passive House Certification

2021 ◽  
Author(s):  
Jimmy Tang
Keyword(s):  
North American ◽  
Heat Recovery ◽  
Regional Climate ◽  
Performance Testing ◽  
Recovery Efficiency ◽  
Passive House ◽  
Testing Procedures ◽  
Margin Of Error ◽  
Passive Houses ◽  
The Impact

The stated heat recovery efficiency of HRV and ERV units in North American passive houses is dependent on the testing procedures and calculation methods established by several pertinent performance testing standards. This project highlights major differences between the applicable HRV/ERV standards for North American passive houses: the European Passive House Institute standard, the Canadian CSA-439-09 standard, and the American HVI-920 standard. It further examines the proposed PHIUS protocol which established ɳPHUIS, a modified HRV/ERV heat recovery efficiency rating to more accurately reflect the North American climate. Simulations were performed to quantify its effect on the modelled annual heat demand for 31 certified passive houses. The results yielded two key findings. First, the margin of error for the new rating, ɳPHUIS, relative to the existing rating, Ɛ, is a function of the regional climate given by the equation: y = 0.00001x + 0.0012. Locations with a colder climate have longer winters, thereby increasing the heating demand and intensifying the margin of error. Second, small to medium sized houses with floor areas (<250m2), which formed 90% of the sample study, have the largest impact on the margin of error up from 3.8% to 12% compared to large homes (>250 m2) from 2.8% to 4.2%. The results validate the necessity for PHIUS’ proposed ɳPHUIS for North American HRV/ERVs.

scholarly journals Analyzing the Impact of the Phius HRV/ERV protocol on North American Passive House Certification

2021 ◽  
Author(s):  
Jimmy Tang
Keyword(s):  
North American ◽  
Heat Recovery ◽  
Regional Climate ◽  
Performance Testing ◽  
Recovery Efficiency ◽  
Passive House ◽  
Testing Procedures ◽  
Margin Of Error ◽  
Passive Houses ◽  
The Impact

The stated heat recovery efficiency of HRV and ERV units in North American passive houses is dependent on the testing procedures and calculation methods established by several pertinent performance testing standards. This project highlights major differences between the applicable HRV/ERV standards for North American passive houses: the European Passive House Institute standard, the Canadian CSA-439-09 standard, and the American HVI-920 standard. It further examines the proposed PHIUS protocol which established ɳPHUIS, a modified HRV/ERV heat recovery efficiency rating to more accurately reflect the North American climate. Simulations were performed to quantify its effect on the modelled annual heat demand for 31 certified passive houses. The results yielded two key findings. First, the margin of error for the new rating, ɳPHUIS, relative to the existing rating, Ɛ, is a function of the regional climate given by the equation: y = 0.00001x + 0.0012. Locations with a colder climate have longer winters, thereby increasing the heating demand and intensifying the margin of error. Second, small to medium sized houses with floor areas (<250m2), which formed 90% of the sample study, have the largest impact on the margin of error up from 3.8% to 12% compared to large homes (>250 m2) from 2.8% to 4.2%. The results validate the necessity for PHIUS’ proposed ɳPHUIS for North American HRV/ERVs.

scholarly journals Metode operasi reverse flow reactor dengan umpan fluktuatif dalam pengolahan emisi gas metana di stasiun kompresor

2018 ◽  
Vol 8 (3) ◽  
pp. 74
Author(s):  
M. Effendy ◽  
Yogi Wibisono Budhi ◽  
Yazid Bindar ◽  
S Subagjo
Keyword(s):  
Global Warming ◽  
Modeling And Simulation ◽  
Flow Reactor ◽  
Switching Time ◽  
Reverse Flow ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Operation Procedure ◽  
Reverse Flow Reactor ◽  
The Impact

Operation method of reverse flow reactor with fluctuating feed for methane gas emmision processing in compressor station.The leak of CH4 from the compressor stations can not be avoided and it may cause the global warming. The impact of the global warming can be reduced by oxidizing CH4 into CO2. The CH4 capture strategy using the exhaust mounted on the top of the building causes (1) CH4 levels detected in the gas mixture is very small (±1% volume), (2) the feed gas temperature is near the ambient temperature (±30 oC), (3) the CH4 concentration fluctuates over time. The reverse flow reactor (RFR) is a fixed bed reactor, which has the ability to abate the leak of CH4 and has the ability to act as an autothermal reactor. The purpose of this research is to find a proper operation procedure of the fixed bed reactor for the oxidation of lean methane emission via modeling and simulation. The reactor model is based on the continuity equation and the heat balance, while the concentration of the feed gas behavior dynamic and modeled as a step function. The model was solved numerically using the software package FlexPDE version 6. At ST (switching time) 50 seconds, the RFR operates autothermally with heat accumulation in the inert section fluctuating between 12.4 to 14.2 kJ. At ST 100 seconds, the heat trap inside the reactor increases monotonically. The use of ST 100 seconds requires an additional operation procedure to keep the reactor safe.Keywords: Global warming, concentration dynamic, autothermal operation, modeling and simulation, reverse flow reactor. AbstrakKebocoran gas CH4 dari stasiun kompresor tidak dapat dihindarkan dan ini merupakan salah satu sumber penyebab pemanasan global. Dampak pemanasan global ini dapat dikurangi dengan mengoksidasi gas CH4 menjadi gas CO2. Strategi penangkapan gas CH4 menggunakan exhaust yang terpasang pada bagian atas gedung menyebabkan (1) kadar CH4 yang terdeteksi dalam campuran gas cukup kecil (±1% volume), (2) temperatur gas umpan mendekati temperatur ruangan (± 30 oC), (3) konsentrasi gas CH4 akan berperilaku dinamik. Reverse flow reactor (RFR) mempunyai kemampuan untuk mengatasi akibat yang ditimbulkan oleh proses penangkapan gas CH4 di stasiun kompresor dan mempunyai kemampuan secara ototermal. Tujuan penelitian ini adalah mendapatkan metode operasi yang tepat untuk mengatasi gas umpan yang berperilaku dinamik. Model yang dikembangkan mengacu pada persamaan kontinuitas dan konsentrasi gas umpan yang berperilaku dinamik dimodelkan sebagai fungsi step. Model diselesaikan menggunakan software FlexPDE versi 6. Penggunaan switching time (ST) yang tepat dapat mengatasi permasalahan konsentrasi gas umpan yang berperilaku dinamik. Pada ST 50 detik, RFR mampu bekerja secara ototermal dengan nilai akumulasi panas di bagian inert yang berfluktuasi antara 12,4–14,2 kJ. Pada ST 100 detik, panas yang terjebak di dalam reaktor semakin lama semakin meningkat. Penggunaan ST 100 detik memerlukan prosedur operasi tambahan untuk menjaga reaktor agar tidak meleleh dan menjaga reaktor tetap beroperasi secara ototermal. Kata Kunci: Pemanasan global, dinamika konsentrasi, operasi ototermal, pemodelan dan simulasi, reaktor aliran bolak-balik.

scholarly journals Characteristics of flow reversal in the kinetic regime

2018 ◽  
Vol 5 (3) ◽  
pp. 490
Author(s):  
Yogi W Budhi
Keyword(s):  
Residence Time ◽  
Surface Coverage ◽  
Ammonia Oxidation ◽  
Flow Reactor ◽  
Catalyst Surface ◽  
Reverse Flow ◽  
Oxidation Kinetic ◽  
Flow Reversal ◽  
Kinetic Regime ◽  
Reverse Flow Reactor

In principle, reactor perturbation by flow reversal can be used for manipulation of catalyst surface coverage if a dedicated and proper operation procedure can be developed. A mathematical model and analysis of reverse flow reactor behaviour for the ammonia oxidation over platinum have been performed. Series of reverse flow experiments were carried out on a laboratory reactor scale. The influence of flow reversals on the conversion and selectivity at various switching times was observed and evaluated. Other process variables such as gas residence time, reaction temperature, and oxygen concentration in the feed were points of interest. Assessment of reactor dynamics in the kinetic regimes can be achieved most expediently by implementing a comparable switching time and gas residence time. Model and experimental results indicate that regular reverse flow operation for manipulation of catalyst surface coverage always induces a decrease of conversion. It was also found that the selectivity due to flow reversal was rather insensitive to changes in the switching frequency.Keywords: Ammonia oxidation, Kinetic regime, Reactor modeling, Residence time distribution, Reverse flow reactor operation, Transient operation AbstrakPada dasarnya pertubasi reaktor oleh aliran balik dapat digunakan untuk mengatasi penutupan permukaan katalis manakala suatu suatu prosedur operasi yang spesifik dan sesuai bisa dibangun. Analisa dan model matematika kelakuan reaktor batik untuk oksidasi amoniak pada pelat platina telah dilakukan. Serangkaian percobaan aliran balik telah dilangsungkan dalam skala laboratorium. Pengaruh aliran batik terhadap konversi dan selektivitas pada berbagaijumlah putaran aliran telah diamati dan dievaluasi. Variabel proses lainnya, seperti waktu tinggal gas, temperature reaksi, dan konsentrasi oksigen pada umpan telah menjadi perhatian pada penelitian ini. Perkiraan dinamika reaktor dalam rejim kinetika umumnya dapat diperoleh melalui penelusuran implementasi jumlah putaran aliran dan waktu tinggal gas dengan perbandingan tertentu. Hasil percobaan dan pemodelan mengindikasikan bahwa operasi aliran batik reguler untuk memanipulasi penutupan permukaan katalis selalu mengakibatkan penurunan konversi. Selain itu, ditemukan juga bahwa selectivitas terhadap pembalikan aliran kurang sensitif terhadap perubahan pada frekuensi putaran aliran.Keywords: Distribusi waktu tinggal, Operasi reaktor aliran batik, Operasi transient, Oksidasi amoniak, Pemodelan reaktor, Rejim kinetika

The Geosciences Applied to Lunar Exploration

1962 ◽  
Vol 14 ◽  
pp. 169-257 ◽  
Author(s):  
J. Green
Keyword(s):  
Lunar Surface ◽  
Probable Mechanism ◽  
Point Of View ◽  
Lunar Exploration ◽  
Geological Model ◽  
Apply Geophysics ◽  
Surface Features ◽  
The Impact

The term geo-sciences has been used here to include the disciplines geology, geophysics and geochemistry. However, in order to apply geophysics and geochemistry effectively one must begin with a geological model. Therefore, the science of geology should be used as the basis for lunar exploration. From an astronomical point of view, a lunar terrain heavily impacted with meteors appears the more reasonable; although from a geological standpoint, volcanism seems the more probable mechanism. A surface liberally marked with volcanic features has been advocated by such geologists as Bülow, Dana, Suess, von Wolff, Shaler, Spurr, and Kuno. In this paper, both the impact and volcanic hypotheses are considered in the application of the geo-sciences to manned lunar exploration. However, more emphasis is placed on the volcanic, or more correctly the defluidization, hypothesis to account for lunar surface features.

МАРКЕТИНГОВІ АСПЕКТИ ФУНКЦІОНУВАННЯ ЛІТЕРАТУРНИХ КОНКУРСІВ ТА ПРЕМІЙ

2020 ◽  
pp. 90
Author(s):  
O. Bondar
Keyword(s):  
Publishing House ◽  
Target Audience ◽  
Point Of View ◽  
Information Support ◽  
Literary Field ◽  
Non Profit ◽  
Functional Aspects ◽  
The Media ◽  
Literary Prizes ◽  
The Impact

<p><em>In this study, I have collected and summarized the functional aspects of a literary prize, contest, and rating, which indicate their affiliation with the marketing complex of the publishing house for the first time. For this purpose, I have analyzed and summarized the common concepts of the functioning of literary prizes and contests as advertising tools for publishing activity. Because the previous studies are only focused on the fact of the impact of the prize on the promotion of editions but do not explain it, these aspects have been considered and introduced by me from the book production’s point of view. I investigated that the prizes and the contests in the literary field are effective marketing tools, which meet many publisher’s needs at the same time and can be considered a non-profit form of capital. I have reviewed the works of other authors, who accept that the economic success of the book is rising if the author is a winner of the literary prize or contest. I have found out that the book prize activates the demand for the book, and the literary contest is a tool to track the reader’s reaction to a future publication. In this way, literary prizes and contests can be considered as a way of conducting a marketing dialogue with the target audience. I have focused on the information support of literary national and international prizes and contests by the media, which attracts attention to the book and forms the reader’s interest. The literary prizes and contests are also considered as a way of exploring trends and their changes, familiarization the popular genres among the target audience and fixation the current choice of modern readers. Literary prizes and contests motivate the authors to improve their literary excellence, are the source of new authors and works, and assist in increasing sales of books. However, further research is recommended.</em></p><strong><em>Key words:</em></strong><em> book prize, book rating, literary contest, literary prize, functions of the literary prizes.</em>

On the Impact of Aptness, Conventionality and Familiarity on Metaphor Processing from a Meta-analytical Point of View

2020 ◽  
Vol 6 (1) ◽  
pp. 55-106
Author(s):  
Csilla Rákosi
Keyword(s):  
Meta Analysis ◽  
Point Of View ◽  
Psycholinguistic Research ◽  
Analytical Point ◽  
Metaphor Processing ◽  
The Impact

Psycholinguistic research into metaphor processing is burdened with empirical problems as experiments provide diverging evidence on the impact of conventionality, familiarity and aptness, and with conceptual issues as the interpretation and operationalization of the three concepts mentioned, as well as the related predictions which can be drawn from theories of metaphor processing, are controversial in the literature. This paper uses tools of statistical meta-analysis in order to bring us closer to the solution of these problems and reveal future lines of research.

Wacana Kolonial dalam Novel Max Havelaar: Sebuah Kajian Poskolonial

Metahumaniora ◽  
2017 ◽  
Vol 7 (3) ◽  
pp. 411
Author(s):  
Abu Bakar Ramadhan Muhamad
Keyword(s):  
Point Of View ◽  
The Other ◽  
The Novel ◽  
Colonial Discourse ◽  
The Impact ◽  
The Voice

AbstrakHegemoni kolonialisme dalam budaya poskolonial merupakan alasan penelitian inikemudian mengkaji wacana kolonial dalam novel Max Havellar (MH) khususnya dampakditimbulkannya. Dampak dimaksud adalah posisi keberpihakan pemikiran tersirat darikarya tersebut. Hasil pembahasan menunjukkan, secara temporal maupun permanen MHmenyuarakan ketidakadilan dalam kondisi-kondisi kolonial menyangkut penindasan sangpenjajah terhadap terjajah. Hanya saja, upaya mengatasnamakan atau mewakili suarakaum terjajah terbukti mengimplikasikan ciri ideologis statis kerangka kolonialisme(orientalisme); yakni cara pandang Eropasentris, di mana “Barat” sebagai self adalah superior,dan “Timur” sebagai other adalah inferior. Dalam konteks poskolonialisme, MH dengan sifatkritisnya yang berupaya “menyuarakan” nasib pribumi terjajah, justru menampilkan stigmapenguatan kolonialitas itu sendiri secara hegemonik. Artinya, “menyuarakan” nasib pribumidimaknai sebagai keberpihankan kolonial yang kontradiktif, di mana stigma penguatankolonialitas justru lebih terasa, ujung-ujungnya melanggengkan hegemoni kolonial. Tidakmembela yang terjajah, tetapi memperhalus cara kerja mesin kolonial.AbstractThe hegemony of colonialism in the culture of postcolonial society is the reason this studythen examines the colonial discourse in the novel Max Havellar (MH) in particular the impactit brings. The impact in question is the implied position of thought in the work. The resultsof the discussion show that, temporarily or permanently, MH voiced injustice in the colonialconditions regarding the oppression of the colonist against the colonized. However, the effort toname or represent the voice of the colonized has proven to imply a static ideological characterin the framework of colonialism (orientalism); ie Eropacentric point of view, in which “West” asself is superior, and “East” as the other is the inferior. In the context of postcolonialism, MH withits critical nature that seeks to “voice” the fate of the colonized natives, actually presents thestigma of strengthening coloniality itself hegemonicly. That is, “voicing” the fate of the pribumiis interpreted as a contradictory colonial flare, where the stigma of strengthening colonialityis more pronounced, which ultimately perpetuates the hegemony of colonialism. No longerdefending the colonized, but refining the workings of the colonial machinery.

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