Effect Of Oxygen Enriched Air Research Articles

Boron-doped rGO electrocatalyst for high effective generation of hydrogen peroxide: Mechanism and effect of oxygen-enriched air

Different B-doped rGO catalysts were prepared and their 2e- oxygen reduction reaction (ORR) performance was investigated. It was found that the 2e- ORR selectivity of B-doped rGO was related to the B content and oxygen mass transfer conditions. The synthesized catalyst exhibited high 2e- ORR selectivity of 95–98.6%, and the H2O2 yield reached up to 95.63 mg cm−2 h−1 at a current density of 200 mA cm−2. Moreover, increasing the oxygen concentration in the gas supplied to the B-doped rGO modified gas diffusion electrode (GDE) only to 30–40% resulted in almost the same H2O2 yield as using pure oxygen. Experimental analysis and theoretical calculations indicated that the isolated B dopant acts as active site for the 2e- ORR. Furthermore, B-doped rGO modified GDE was applied to the electro-Fenton system to continuously degrade organic pollutants. This work will be beneficial for the study and application of carbon-based ORR catalysts.

Experimental investigation on effects of oxygen enriched air on performance, combustion and emission characteristics of a methanol fuelled spark ignition engine

The present experimental investigation deals with the study of the effect of oxygen enriched intake air on performance, emission and combustion characteristics of a methanol (M100) fuelled spark ignition engine. The oxygen in the intake air of the engine fuelled with methanol was enriched from 23% (by mass) with base oxygen to 26.5%, 38.7% and 60.4%. The brake thermal efficiency increased drastically with methanol with 38.7% and 60.4% enriched air by 9.9% and 20.5% respectively. The peak pressure and cumulative heat release with the highest enriched air (60.4%) are higher about 2 and 1.27 times than base oxygen percentage (23% by mass). The ignition delay and combustion duration decreased by 35.24% and 57.8% respectively. Carbon monoxide (CO) and hydrocarbon (HC) emissions with the highest enriched air decreased substantially by 48.59% and 30.9%. However, nitrogen oxides (NOx) emission increased drastically by 112.2% with 38.7% of oxygen but it decreased by 31.5% with 60.4% oxygen enriched air which is lower than base oxygen. A notable conclusion emerged from this study is that a methanol fuelled engine with the oxygen enriched air (60.4%) could emit very lower emissions (CO, HC, NOx) along with improved thermal efficiency compared to base oxygen (23% by mass).

Experimental Model Development of Oxygen-Enriched Combustion Kinetics on Porous Coal Char and Non-Porous Graphite

The effect of oxygen-enriched air on low-rank coal char combustion was experimentally investigated. In this work, a coal-heating reactor equipped with a platinum wire mesh in the reaction chamber was used to analyze the combustion temperature, reaction time, and reaction kinetics. Increasing the oxygen content of the primary combustion air increased the combustion temperature and decreased the reaction time. As the oxygen content increased from 21% to 30%, the average temperature increased by 47.72 K at a setup temperature of 1673 K, and the reaction time decreased by 30.22% at the same temperature. The graphite sample exhibited similar trends in temperature and reaction time, although the degree of change was smaller because the pores produced during char devolatilization expanded the active surface available for oxidation of the char sample. A mathematical model was used to define the intrinsic kinetics of the reaction. As the oxygen content increased from 21% to 30%, the reaction rate of the low-rank coal char increased. These results were also compared with those of the graphite sample.

Review of Membrane Oxygen Enrichment for Efficient Combustion

Oxygen enrichment from air is a simple way of increasing the efficiency of combustion process, as in oxy-combustion. Oxy-combustion has become one of the most attracting combustion technologies because of its potential to address both pollutant reduction and CO2 capture. In oxy-combustion, the fuel and recycled flue gas are combusted with oxygen enriched air (OEA). By using OEA, many benefits can be obtained, such as increasing available heat, improving ignition characteristics, flue gas reduction, increasing productivity, energy efficiency, turndown ratio, and flame stability. Membrane-based gas separation for OEA production becomes an attractive technology over the conventional technology due to the some advantages, including low capital cost, low energy consumption, compact size, and modularity. A single pass through membrane usually can enrich O2 concentration in the air up to 35% and a 50% concentration can be achieved with a double pass of membrane. The use of OEA in the combustion process eliminates the presence of nitrogen in the flue gas. Hence, the flue gas is mainly composed of CO2 and condensable water that can be easily separated. This paper gives an overview of oxy-combustion with membrane technology for oxygen enrichment process. Special attention is given to OEA production and the effect of OEA to the efficiency of combustion.

Effects of oxygen-enriched air on cognitive performance during SCUBA-diving – an open-water study

ABSTRACTBackround: Nitrogen narcosis impairs cognitive function, a fact relevant during SCUBA-diving. Oxygen-enriched air (nitrox) became popular in recreational diving, while evidence of its advantages over air is limited. Aim: Compare effects of nitrox28 and air on two psychometric tests.Methods: In this prospective, double-blind, open-water study, 108 advanced divers (38 females) were randomized to an air or a nitrox-group for a 60-min dive to 24 m salt water. Breathing gas effects on cognitive performance were assessed during the dive using a short- and long-term memory test and a number connection test.Results: Nitrox28 divers made fewer mistakes only on the long-term memory test (p = 0.038). Female divers remembered more items than male divers (p < 0.001). There were no significant differences in the number connection test between the groups.Conclusion: Likely owing to the comparatively low N2 reduction and the conservative dive, beneficial nitrox28 effects to diver performance were moderate but could contribute to diving safety.

Simulation the Effect of Oxygen-Enriched Air on the Performance Characteristics of a Gasoline Engine

Simulation the Effect of Oxygen-Enriched Air on the Performance Characteristics of a Gasoline Engine

Effect of oxygen enriched air on porous radiant burner performance and NO emissions

Gas fired radiant burners are used owing to their simplicity, low cost and to avoid the difficulties and disadvantages of conventional burners i.e., low dynamic range and high production of pollutants. On the basis of this combustion principle, combustion characteristics of porous medium gas burners have been experimentally studied to investigate parameters affect the performance of porous medium burners, and the effect of oxygen enriched air on the performance. The combustion in porous inert media was investigated using mullite as a burner and liquefied petroleum gas “LPG” as a premixed fuel with air to show the effect of equivalence ratio and firing rate on the radiation efficiency, surface and exhaust gas temperatures. Radiation efficiency up to 45% can be achieved depending on operating conditions. The surface temperature was much lower than the adiabatic flame temperature of the LPG-air mixture at the same equivalence ratio. The improvement of the burner performance, using oxygen enriched air is investigated. The oxygen in the combustion air was increased up to 25%. The experimental results showed that the radiation efficiency of the burner was increased markedly with rising oxygen concentrations in the combustion air. The surface temperature also increased, while the exhaust gas temperature decreased.

Effects of oxygen enriched air on the operation and performance of a diesel-biogas dual fuel engine

The effect of oxygen enriched air was tested for a diesel-biogas dual fuel engine. The operation and performance characteristics, such as thermal efficiency, pollutant emissions and combustion parameters were determined. Experiments have been carried out with a stationary compression ignition (CI) engine coupled with a generator in dual mode using a typical biogas composition of 60 vol. %CH4 and 40% vol. %CO2. For every engine load evaluated, the oxygen concentration in the intake air engine was varied from 21% to 27% O2 v/v. Ignition delay time and methane emissions were decreased when using oxygen enriched air with respect to normal air (21%O2), whereas the thermal efficiency was increased.

The O2-enriched air gasification of coal, plastics and wood in a fluidized bed reactor

The effect of oxygen-enriched air during fluidized bed co-gasification of a mixture of coal, plastics and wood has been investigated. The main components of the obtained syngas were measured by means of on-line analyzers and a gas chromatograph while those of the condensate phase were off-line analysed by means of a gas chromatography–mass spectrometer (GC–MS). The characterization of condensate phase as well as that of the water used as scrubbing medium completed the performed diagnostics. The experimental results were further elaborated in order to provide material and substances flow analyses inside the plant boundaries. These analyses allowed to obtain the main substance distribution between solid, gaseous and condensate phases and to estimate the conversion efficiency of carbon and hydrogen but also to easily visualise the waste streams produced by the process. The process performance was then evaluated on the basis of parameters related to the conversion efficiency of fuels into valuable products (i.e. by considering tar and particulate as process losses) as well as those related to the energy recovery.

The effect of oxygen enriched air obtained by gas separation membranes from the emission gas of diesel engines

Gas separation membranes with polydimethylsiloxane(PDMS)/polystyrene(PS) were prepared by using the sequential interpenetrating polymer network (IPN) method with various PS contents (10–70wt%). These gas separation membranes can be applied to reduce the smoke density in the emission gas of diesel engines. PS content has a pronounced effect on the membrane performance. It was found that the optimized PS contents in the final membrane were 50wt%. The emission capacities of diesel engines used in this study were 632 cc and 11,149 cc. When the oxygen separation membrane was used in the diesel engines, the smoke density of both diesel engines was remarkably reduced (35–73%). The oxygen concentration in the inlet air affects the composition of the emission gases. Especially, hydrocarbon (HC) decreased with the increase of oxygen concentration.

酸素富化空気による省エネルギーと低ＮＯｘ燃焼に関する研究 ＩＩ 初期温度と燃焼排ガス巻き込みによるＮＯｘへの影響

The combustion with oxygen enriched air has a potential of the fuel savings and the consequent reduction of carbon dioxide emission. The fuel savings were examined by the enthalpy of equilibrium state in case of oxygen enriched combustion. The fuel consumption in case of 30-40% oxygen enriched air is reduced by 5.9-9.1% as compared with the case of 21% oxygen air at exhaust temperature 773K after whichsensible heat of exhaust gas exchange the sensible heat of combustion air. However, NO emission increases with the enrichment of oxygen in the air and the increase of initial temperature. The effect of oxygen enriched air and initial temperature on NO emissions in the methane premix flame was numerically analyzed with detailed chemistry for the equivalent ratio of 0.5-2.0. The results revealed that the low NOx combustion with 30% oxygen enriched air can be achieved in case of the fuel rich (φ>2.0) condition. Furthermore, the effect of oxygen enriched air and entrainment of exhaust gas was analyzed numerically. The low NOx combustion with 30% oxygen enriched air and initial temperature 798K can be achieved in case of the fuel lean (φ<0.5) or fuel rich (φ>1.5) condition and mixing ratio 0.5 which is expressed that the ratio mole of exhaust gas against the mole of fuel and oxygen enriched air.

酸素富化空気による省エネルギーと低ＮＯｘ燃焼に関する研究 Ｉ 省エネルギー効果と低ＮＯｘ燃焼の可能性の検討

The combustion with oxygen enriched air has a potential of the fuel savings and the consequent reduction of carbon dioxide emission. The fuel savings were examined by the enthalpy of equilibrium state in case of oxygen enriched combustion. The fuel consumption in case of 30-40% oxygen enriched air is reduced by 20-30% as compared with the case of 21% oxygen air. However, NO emission increases with the enrichment of oxygen in the air. The effect of oxygen enriched air on NO emission in the methane premix flame was numerically analyzed with detailed chemistry for the equivalent ratio of 0.5-2.0 The results revealed that the low NOx combustion with 30% oxygen enriched air can be achieved in case of the fuel lean (φ<0.6) or fuel rich (φ>1.5) condition. It was also shown that the burning velocity with oxygen enriched air is considerably high even at the fuel lean and fuel rich condition.

Effects of 5 mg Sublingual Nitrendipine in Patients with Precapillary Pulmonary Hypertension due to Pulmonary Fibrosis

In 10 patients with precapillary pulmonary hypertension due to pulmonary fibrosis, the arterial blood pressure, right heart hemodynamics, cardiac output, and arterial oxygen partial pressure were measured to evaluate the benefits of acute sublingual (5 mg) nitrendipine. Additionally, the effect of oxygen enriched air was compared to control. At rest, nitrendipine significantly diminished arterial blood pressure [102 +/- 3 to 93 +/- 3 mm Hg (mean +/- SEM)], right atrial pressure (5.7 +/- 0.9 to 3.4 +/- 0.8 mm Hg), mean pulmonary artery pressure (33.4 +/- 3.5 to 29.8 +/- 3.3 mm Hg), and pulmonary artery wedge pressure (13.0 +/- 2.0 to 6.8 +/- 0.8 mm Hg). During exercise, nitrendipine reduced mean pulmonary artery pressure (54.5 +/- 4.8 to 49.3 +/- 4.7 mm Hg) and right atrial pressure (9.3 +/- 1.3 to 6.8 +/- 1.4 mm Hg). A diminuation of arterial partial oxygen pressure did not occur at rest (63.2 +/- 3.8 mm Hg) or during exercise (50.9 +/- 5.1 mm Hg). Thus, nitrendipine causes a slight but significant improvement of right heart hemodynamics. The occurrence of arteriovenous intrapulmonary shunting due to vasodilatating effects of nitrendipine can be excluded. Also, nitrendipine can safely be used in combined arterial hypertension and pulmonary fibrosis.