Economic and Environmental Considerations During Low Fresh Gas Flow Volatile Agent Administration After Change to a Nonreactive Carbon Dioxide Absorbent

Absorbents used in closed and semi-closed circuit environments play a key role in preventing carbon dioxide poisoning. Here we present an analysis of one of the most common carbon dioxide absorbents—soda lime. In the first step, we analyzed the composition of fresh and used samples. For this purpose, volumetric and photometric analyses were introduced. Thermal properties and decomposition patterns were also studied using thermogravimetric and X-ray powder diffraction (PXRD) analyses. We also investigated the kinetics of carbon dioxide absorption under conditions imitating a closed-circuit environment.

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Understanding Carbon Dioxide Transfer in Direct Methanol Fuel Cells Using a Pore-Scale Model

Journal of Electrochemical Energy Conversion and Storage ◽

10.1115/1.4050369 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Nathaniel Metzger ◽

Archana Sekar ◽

Jun Li ◽

Xianglin Li

Keyword(s):

Carbon Dioxide ◽

Pressure Drop ◽

Gas Flow ◽

Direct Methanol Fuel Cells ◽

Gas Pressure ◽

Mass Transfer Resistance ◽

Transfer Resistance ◽

Cell Components ◽

Direct Methanol ◽

Methanol Fuel Cells

Abstract The gas flow of carbon dioxide from the catalyst layer (CL) through the microporous layer (MPL) and gas diffusion layer (GDL) has great impacts on the water and fuel management in direct methanol fuel cells (DMFCs). This work has developed a liquid–vapor two-phase model considering the counter flow of carbon dioxide gas, methanol, and water liquid solution in porous electrodes of DMFC. The model simulation includes the capillary pressure as well as the pressure drop due to flow resistance through the fuel cell components. The pressure drop of carbon dioxide flow is found to be about two to three orders of magnitude higher than the pressure drop of the liquid flow. The big difference between liquid and gas pressure drops can be explained by two reasons: volume flowrate of gas is three orders of magnitude higher than that of liquid; only a small fraction of pores (<5%) in hydrophilic fuel cell components are available for gas flow. Model results indicate that the gas pressure and the mass transfer resistance of liquid and gas are more sensitive to the pore size distribution than the thickness of porous components. To buildup high gas pressure and high mass transfer resistance of liquid, the MPL and CL should avoid micro-cracks during manufacture. Distributions of pore size and wettability of the GDL and MPL have been designed to reduce the methanol crossover and improve fuel efficiency. The model results provide design guidance to obtain superior DMFC performance using highly concentrated methanol solutions or even pure methanol.

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High Flue Gas Flow Rate Tests for Removal and Recovery of Carbon Dioxide under Power Plant Effluent Gas Conditions

KAGAKU KOGAKU RONBUNSHU ◽

10.1252/kakoronbunshu.30.758 ◽

2004 ◽

Vol 30 (6) ◽

pp. 758-761

Author(s):

Tomio MIMURA ◽

Yasuyuki YAGI ◽

Masaki IIJIMA ◽

Ryuji YOSIYAMA ◽

Takahito YONEKAWA

Keyword(s):

Carbon Dioxide ◽

Power Plant ◽

Flow Rate ◽

Flue Gas ◽

Gas Flow ◽

Gas Flow Rate ◽

Power Plant Effluent ◽

Removal And Recovery

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INFLUENCE OF CARBON DIOXIDE ABSORBENT AND PERCENTAGE ATMOSPHERIC CARBON DIOXIDE ON OXYGEN UPTAKE BY BOAR SPERMATOZOA

Canadian Journal of Animal Science ◽

10.4141/cjas72-006 ◽

1972 ◽

Vol 52 (1) ◽

pp. 57-63

Author(s):

L. M. SANFORD ◽

G. J. KING

Keyword(s):

Carbon Dioxide ◽

Oxygen Uptake ◽

Incubation Period ◽

Potassium Hydroxide ◽

Atmospheric Carbon Dioxide ◽

Initial Value ◽

Atmospheric Carbon ◽

Cell Motion ◽

Boar Spermatozoa ◽

Carbon Dioxide Absorbent

Boar spermatozoa were diluted in Ringer’s fructose or sulfate buffer and incubated aerobically for 4 hr at 37 C (a) in the presence of potassium hydroxide (KOH), hyamine hydroxide, or diethanolamine (DEA) absorbents, and (b) in 1, 2, or 3% atmospheric levels of carbon dioxide. Oxygen uptake by boar spermatozoa was enhanced by the presence of DEA compared with KOH and hyamine hydroxide. Incubation with DEA resulted in increased spermatozoan livability, more desirable cell motion, and smaller increases in buffer pH. Oxygen uptake by boar spermatozoa was optimum with 1 or 2% carbon dioxide, depending upon which buffer cells were diluted in. Levels of 2 and 3% carbon dioxide maintained oxygen uptake and livability of boar spermatozoa during later stages of the incubation period equally as well as 1% carbon dioxide. As the level of atmospheric carbon dioxide increased, buffer pH remained closer to the initial value.

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A new real-time and precision capnography for human respiration carbon dioxide concentration

Perfusion ◽

10.1177/0267659110380772 ◽

2010 ◽

Vol 25 (6) ◽

pp. 399-408 ◽

Cited By ~ 3

Author(s):

Jiachen Yang ◽

Bin Wang ◽

Ran Xu ◽

Lei Wang

Keyword(s):

Carbon Dioxide ◽

Real Time ◽

Gas Flow ◽

Measurement Accuracy ◽

Carbon Dioxide Concentration ◽

Main Stream ◽

Temperature Drift ◽

New Device ◽

Human Respiration ◽

Gas Measurement

This paper is a description of the designing of a new mainstream device to measure human respiration carbon dioxide concentration, based on non-dispersive infrared (NDIR) absorption technology. The device can be used to accurately monitor the cardiopulmonary status during anaesthesia and mechanical ventilation in real time. This new device can not only make up the error of real-time gas measurement of the side-stream device, but also make up the accuracy of the main-stream device. In the paper, four issues which can affect the measurement accuracy were considered: respiration gas flow, turbulence of the light source with all ranges of wavelength, temperature drift and signal noise. The experimental results showed that the device could produce a stable output signal and deviation of measurement accuracy could be achieved to within 4%.

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COMPARATIVE CALCULATIONS OF HYDRODYNAMIC AND STRUCTURAL PARAMETERS OF THE ABSORBER TO IMPROVE THE EFFICIENCY OF TREATMENT OF INDUSTRIAL WATERS OF ENTERPRISES

Известия вузов. Пищевая технология ◽

10.26297/0579-3009.2020.1.22 ◽

2020 ◽

Author(s):

Е.Г. СТЕПАНОВА ◽

Н.А. ПУХАЧЕВ ◽

Б.Ю. ОРЛОВ ◽

М.А. ПЕЧЕРИЦА

Keyword(s):

Waste Water ◽

Carbon Dioxide ◽

Gas Flow ◽

Structural Parameters ◽

Active Surface ◽

Column Diameter ◽

Gas Flow Rate ◽

Maximum Value ◽

Water Pretreatment ◽

Production Water

Проведены сравнительные гидродинамические и конструктивные расчеты процесса абсорбции углекислого газа и аммиака из отработанных производственных вод пищевых предприятий в аппаратах с деревянными хордовыми насадками, с насадками в виде керамических колец Палля и в адсорбере с хордовыми насадками с предварительной обработкой воды в диафрагменном электролизере. Расчеты выполнены с помощью пакета Mathcad 13. Установлено, что максимальное значение объемной интенсивности при расходе газа 13,9 м3/с и плотности орошения 9,7 Ч 104 м3/(м2 Ч с) получено в адсорбере с хордовыми насадками при предварительной обработке воды в диафрагменном электролизере. Оптимальные размеры колонны адсорбера: диаметр 1,8 м, доля активной поверхности насадки 0,914. Предварительная электрообработка воды перед абсорбцией значительно повышает эффективность очистки, что позволяет очищенную от газовых примесей производственную воду повторно использовать на технологические нужды пищевых предприятий. Comparative hydrodynamic and structural calculations of the process of absorption of carbon dioxide and ammonia from waste water of food enterprises in devices with wooden chord nozzles, with nozzles in the form of ceramic Pall rings and in an adsorber with chord nozzles with pretreatment of water in a diaphragm electrolyzer were carried out. The calculations are performed using the Mathcad 13 package. It was found that the maximum value of the volumetric intensity at a gas flow rate of 13,9 m3/sec and the irrigation density of 9,7 Ч 104 m3/(m2 Ч sec) was obtained in an adsorber with chord nozzles during pretreatment of water pretreatment of water in a diaphragm electrolyzer. Optimal dimensions of the adsorber column: diameter 1,8 m, the proportion of the active surface of the nozzle 0,914. Preliminary electrical treatment of water before absorption significantly increases the efficiency of purification, which allows purified from gas impurities production water to be reused for the technological needs of food enterprises.

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Promoting low-flow anaesthesia and volatile anaesthetic agent choice

BMJ Open Quality ◽

10.1136/bmjoq-2018-000479 ◽

2019 ◽

Vol 8 (3) ◽

pp. e000479 ◽

Cited By ~ 3

Author(s):

Louise A Carter ◽

Molola Oyewole ◽

Eleanor Bates ◽

Kate Sherratt

Keyword(s):

Gas Flow ◽

Anaesthetic Agent ◽

Cost Effective ◽

Low Flow ◽

Volatile Agent ◽

Monthly Basis ◽

Improvement Project ◽

Effective Manner ◽

Low Flow Anaesthesia ◽

Volatile Agents

BackgroundAs doctors, we are increasingly aware of the financial implications of our practice. The need to work in a more conscientious, efficacious and cost-effective manner is greater than ever before. Environmental and financial benefits can be seen through employing the use of low-flow anaesthesia.AimsThis quality improvement project aimed to make anaesthetic practice more environmentally friendly and to reduce departmental spending. This could be achieved by promoting the use of low-flow anaesthesia and by encouraging isoflurane use where appropriate.MethodsAll anaesthetic consultants and trainees were invited to fill out an initial questionnaire relating to their personal preferences and practices when conducting anaesthesia. There were specific questions relating to low-flow anaesthesia and isoflurane use. Our main measure of improvement was any decrease in the number of bottles of volatile agent ordered by the department from pharmacy. Monthly spot audits were conducted to assess gas flow rates and volatile agent use in theatre. Departmental spending figures relating to the purchase of volatile agent bottles were obtained from pharmacy. Information was then disseminated to anaesthetists on a monthly basis via a ‘low-flow board’, which showed pictorial and graphical representations of differing gas flows and volatile agent usage in relation to cost.ResultsOur project showed a trend for the increased use of low-flow anaesthesia within the department. We also showed a decrease in the number of bottles of volatile agent ordered: 18% fewer bottles ordered compared with the same period the previous year. This represented a 25% decrease in total departmental expenditure on volatile agents despite an increase in theatre activity.ConclusionIncreasing awareness regarding anaesthetic choices and promoting low-flow anaesthesia and isoflurane use, translated into an overall decreased departmental spend on volatile agents without affecting patient care.

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Biological treatment characteristics of benzene and toluene in a biofilter packed with cylindrical activated carbon

Water Science & Technology ◽

10.2166/wst.2002.0716 ◽

2002 ◽

Vol 46 (11-12) ◽

pp. 51-56 ◽

Cited By ~ 3

Author(s):

G.-W. Li ◽

H.-Y. Hu ◽

J.-M. Hao ◽

H.-Q. Zhang

Keyword(s):

Carbon Dioxide ◽

Activated Carbon ◽

Gas Flow ◽

Removal Rate ◽

Carbon Dioxide Concentration ◽

Organic Load ◽

Filler Materials ◽

Removal Capacity ◽

Bacillus Spore ◽

Maximum Removal

The biodegradation of toluene and benzene in a biofilter using cylindrical activated carbon as the filler materials was studied. Three gas flow rates, i.e. 0.25, 0.50 and 0.75 m3/h, corresponding to empty bed gas residence of 75, 37.5 and 25 s, respectively, and total organic load lower than 400 g/m3.h were tested. The biofilter proved to be highly efficient in biodegradation of toluene and benzene, and toluene was more easily degraded than benzene. When each inlet load was lower than 150 g/m3.h, removal rate increased with inlet load and reached a maximum, which was 150 and 120 g/m−3.h for toluene and benzene, respectively. For inlet load higher than the maximum removal capacity conditions, the removal rate decreased with inlet load. Carbon dioxide concentration profile through the biofilter revealed that the mass ratios of carbon dioxide produced to the toluene and benzene removed were 2.15 g(CO2)/g(toluene) and 1.67 g(CO2)/g(benzene), which furthermore, confirmed the biodegradation performance in biofilter. The observation of biotic community demonstrated that the microbes consisted of bacillus, spore bacillus and fungi, of which the spore bacillus was dominant.

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Hyperbaric Testing of an Alternative Approach to Remove Carbon Dioxide From Underwater Life Support Equipment

Volume 8A: Ocean Engineering ◽

10.1115/omae2014-23028 ◽

2014 ◽

Author(s):

M. Nuckols ◽

S. Kolaczkowski ◽

S. Awdry ◽

T. Smith ◽

D. Thomas

Keyword(s):

Carbon Dioxide ◽

Surface Pressure ◽

Gas Flow ◽

Life Support ◽

Cold Water ◽

Research Effort ◽

Co2 Absorption ◽

Cold Temperatures ◽

Wide Range ◽

Current Water

Traditional CO2 absorption methods for underwater life support equipment use alkali metal hydroxide chemical beds — mostly calcium hydroxide — that have been shown to have poor absorption efficiencies at cold temperatures, and must be replaced at considerable trouble and expense on a frequent basis. With chemical utilizations as low as 20% in water temperatures of 2°C, these hydroxides do not lend themselves to applications requiring extended durations in cold water due to the inability to carry sufficient quantities of expendables. A joint research effort between Duke University and the University of Bath has verified the feasibility in laboratory trials of an alternative carbon dioxide removal method that intimately mixes seawater with breathing circuit gases within a packed bed of Dixon rings. Based on the results of these laboratory trials, two multi-path scrubber prototypes were designed and fabricated for unmanned testing. In March 2013, the hyperbaric performance of these prototype scrubbers was characterized over a wide range of gas and water flow rates when operating the scrubbers in counter-current (water flowing in the opposite direction as gas flow) and co-current (water flowing in the same direction as gas flow) fashion. Significant findings from these tests included the following: • Both scrubber prototypes were found to be capable of delivering exit CO2 levels below 0.5 vol% (surface equivalent) at respiratory rates up to 22.5 liters per minute and at depths ranging from 0 to 40 meters of seawater (MSW). • Negligible collateral O2 absorption was observed at surface pressure (exit O2 levels were typically above 20.2 vol%), and exit O2 levels were typically above 18.4% during testing at 10 MSW. • At surface pressure, both prototypes had significantly lower breathing resistances than design goals established by the U. S. Navy.

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