scholarly journals Multiscale supercomputer modeling of gas purification processes by the adsorption method

Author(s):  
С.В. Поляков ◽  
Ю.Н. Карамзин ◽  
Т.А. Кудряшова ◽  
В.О. Подрыга ◽  
Д.В. Пузырьков ◽  
...  

Рассматривается проблема суперкомпьютерного моделирования процессов очистки воздушной среды от мелкодисперсных твердых загрязняющих примесей, кластеризованных в виде наночастиц. Моделируемый способ очистки предполагает применение нанофильтров и сорбентов. Оба способа очистки часто комбинируются в современных очистных системах. Способ очистки с помощью нанофильтров позволяет получить высокое качество, но является дорогостоящим вследствие необходимости частой замены фильтрующих элементов (мембран). Способ очистки с помощью сорбентов оказывается несколько хуже по качеству, однако позволяет проводить очистку многократно после промывки сорбента специальными жидкостями. Для оптимизации систем воздушной очистки, использующих нанофильтры и сорбенты, необходимо детальное исследование протекающих в системе очистки процессов. В предлагаемом исследовании рассматривается часть проблемы, связанная с прохождением воздушного потока, содержащего твердые наночастицы загрязнителя, через слой гранулированного сорбента. Для этого разработаны многомасштабная математическая модель, численный алгоритм и параллельная реализация модели на макроскопическом масштабе. Новизна подхода связана с использованием квазигазодинамической модели для описания течения в сорбирующем слое и нескольких вариантов граничных условий на гранулах сорбента. Предварительные расчеты показали возможность расчета течений подобного класса. This paper considers the problem of supercomputer modeling of processes for cleaning the air from fine-dispersed solid polluting impurities clustered in the form of nanoparticles. The simulated purification method involves the use of nanofilters and sorbents. Both the purification methods are often combined in modern treatment systems. The cleaning method using nanofilters allows one to obtain the high quality of purification, but is expensive due to the need for frequent replacement of filter elements (membranes). The cleaning method using sorbents is somewhat worse in quality, however, it allows cleaning many times after washing the sorbent with special liquids. To optimize air cleaning systems using nanofilters and sorbents, a detailed study of the processes occurring in the cleaning system is necessary. The proposed study considers part of the problem associated with the passage of an air stream containing solid pollutant nanoparticles through a layer of granular sorbent. To accomplish this, a multiscale mathematical model, a numerical algorithm and a parallel implementation of the model on a macroscopic scale have been developed. The novelty of the approach is associated with the use of a quasigasdynamic model to describe the flow in the sorbing layer and several variants of the boundary conditions on the sorbent granules. Preliminary calculations show the possibility of calculating flows of a similar class.

ANRI ◽  
2020 ◽  
Vol 0 (4) ◽  
pp. 64-70
Author(s):  
Vladimir Povarov ◽  
Igor' Gusev ◽  
Sergey Rosnovsky ◽  
Dmitriy Statsura ◽  
Vladimir Kazansky ◽  
...  

The article is dedicated to the assessment of the experience in drainage water purification from radionuclides using ion-selective purification method on Units 1,2 Novovoronezh-2 NPP. Application of an ion-selective sorbent based on nickel ferrocyanide, as well as the preliminary oxidation of corrosive origin radiongjuclides, allow to achieve a satisfactory quality of purification from Cs-134, Cs-137, Co-60, Co 58, Mn-54, Cr-51. However, this method turned out to be ineffective for drainage water purification from Be-7, Sb-124, Sb-125. The article presents a possible method for drainage water purification from Be-7, Sb-124, Sb-125 using an iron-based coagulant, prospects for the modernization of the ion-selective drainage water purification plant, as well as plans to improve methods for drainage water purification at Novovoronezh-2 NPP


2021 ◽  
pp. 097152312110163
Author(s):  
A. H. M. Kamrul Ahsan ◽  
Peter Walters ◽  
Md. Adil Khan

This study compares the state of city government service delivery for communities living in different areas with different level of affluence in Rajshahi City in Bangladesh. Based on the results of a qualitative study, we found a significant service disparity between the affluent and the poor communities. This disparity is due to the inability of the poor to hold service providers accountable, attributable to a lack of knowledge about services and a lack of social status. Lack of quality monitoring and a marked bias in the quality of interactions between the poor and the affluent contribute to the service disparity This disparity is largely invisible to the poor who, instead of comparing themselves with the affluent citizens, compare themselves with a similar class of people.


2012 ◽  
Vol 22 (03) ◽  
pp. 1250007 ◽  
Author(s):  
PEDRO RODRÍGUEZ ◽  
MARÍA CECILIA RIVARA ◽  
ISAAC D. SCHERSON

A novel parallelization of the Lepp-bisection algorithm for triangulation refinement on multicore systems is presented. Randomization and wise use of the memory hierarchy are shown to highly improve algorithm performance. Given a list of selected triangles to be refined, random selection of candidates together with pre-fetching of Lepp-submeshes lead to a scalable and efficient multi-core parallel implementation. The quality of the refinement is shown to be preserved.


2014 ◽  
Vol 70 (a1) ◽  
pp. C337-C337
Author(s):  
Carina Lobley ◽  
Juan Sanchez-Weatherby ◽  
James Sandy ◽  
Marco Mazzorana ◽  
Tobias Krojer ◽  
...  

A typical protein crystal contains 30-60% solvent. For a naked crystal, this solvent is distributed between solvent shells, where water and solvent molecules make specific interactions with the crystalline protein, and solvent channels filled with disordered solvent molecules. This internal solvent map of the crystal can be modified by placing the crystal in a dehydrating environment. This may in turn induce changes to the crystal lattice and affect mosaicity, resolution and quality of diffraction data. A dehydrating environment can be generated around a crystal in several ways with various degrees of precision and complexity. In this study we have used the HC1 device (Maatel) to mount crystals an air stream of known relative humidity – a precise yet hassle-free approach to altering crystal hydration. We set out to analyse a range of different crystals to establish usable protocols that will allow one to explore to crystal hydration space, either by preparing samples before synchrotron beamtime or by undertaking the experiments during beamtime. Our results, considered in the light of the literature surrounding crystal dehydration, provide guidance for when dehydration can help diffraction.


Author(s):  
Nagisa Onoda ◽  
Osamu Nakabeppu

The aim of this study is to develop a new air cleaning method being applicable to suspended particulate matters (SPM) of wide sizes. We experimentally studied about the effects of a humidity swing operation where sample air is continuously humidified with heating and dehumidified with cooling. The total of SPM concentration of sample air decreased with the humidity swing operation; however, the concentration of SPM from 0.3 to 1 μm markedly increased. Suction flow accompanying condensation, cohesion and thermophoresis were considered as the SPM reduction effects. It would appear that the nano-size SPM grew to submicron size by nuclear condensation and submicron size SPM increased. The experimental results showed that the SPM concentration of 0.3 μm or less decreased by 89% and the total of that decreased by 80%. The applicability of the humidity swing operation to removal of SPM including nano size SPM was shown by the results. Also, exponential reduction of the SPM concentration was demonstrated with applying the repeated humidity swing operation in a circulation air-cleaning apparatus. This method is expected to become effective air cleaning method applicable to wide size range of SPM.


2013 ◽  
Vol 5 (4) ◽  
pp. 376-381 ◽  
Author(s):  
Alvydas Zagorskis ◽  
Aleksandra Milaknytė

Air cleaning efficiency tests on placing material load into the lavsan biofilter were carried out. Testing included butanol vapour-contaminated air stream pulled during the boot. The studies were conducted by the Department of Environmental Protection at VGTU that developed a biofilter – an experimental biological air cleaning device. Measurements were done using 60 l/min and 90 l/min air volume aspirators under the initial pollutant concentration making 180, 305, 350, 440 and 545 mg/m3. Before measuring the concentrations of butanol lavsan cartridge, loading was periodically irrigated with nutrient-rich solution. In order to evaluate the influence of microorganisms on genus Pseudomonas, cleaning efficiency tests were repeated – Boot was moistened with water only, which allowed measuring butanol vapour concentrations after the cartridge. At the concentration of 180±9 mg/m3, efficiency reached 41% at a speed of 0,07 m/s and 46 % at a speed of 0,10 m/s. Measuring the performance of the initial concentration of 545±67 mg/m3, efficiency was 54% at 0,07 m/s and 53 % at 0,10 m/s respectively. Article in Lithuanian. Santrauka Atlikti oro valymo efektyvumo tyrimai į lašelinį biofiltrą įkrovus lavsano medžiagos įkrovą. Bandymų metu pro įkrovą buvo traukiamas butanolio garais užterštas oro srautas. Tyrimai atliekami naudojant VGTU Aplinkos apsaugos katedroje sukurtą eksperimentinį biologinį oro valymo įrenginį – biofiltrą. Matavimai atlikti leidžiant 60 l/min. ir 90 l/min. oro kiekį aspiratoriumi. Pradinės teršalo koncentracijos – 180, 305, 350, 440, 545 mg/m3. Prieš matuojant butanolio koncentracijas panaudojant lavsano medžiagos kasetę, įkrova buvo periodiškai drėkinama maistinių medžiagų prisotintu tirpalu. Pseudomonas genties mikroorganizmų įtakai valymo efektyvumui įvertinti tyrimai buvo pakartoti – įkrovos sudrėkinamos tik vandeniu, leidžiami butanolio garai, ir matuojamos koncentracijos panaudojus lavsano medžiagos kasetę. Esant 180±89 mg/m3 koncentracijai biofiltro oro valymo efektyvumas siekė 41 %, kai per įkrovą leidžiamo dujų srauto greitis buvo 0,07 m/s, ir 46 %, kai greitis 0,10 m/s. Nustatyta valymo efektyvumas. Esant 545±55 mg/m3 pradinei koncentracijai jis siekė 54 % (0,07 m/s) ir 53 % (0,10 m/s).


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