Sweep Gas Flow Rate Research Articles

Hydrogen-Rich Syngas Production in a Ce0.9Zr0.05Y0.05O2−δ/Ag and Molten Carbonates Membrane Reactor

This study proposes a new dense membrane for selectively separating CO2 and O2 at high temperatures and simultaneously producing syngas. The membrane consists of a cermet-type material infiltrated with a ternary carbonate phase. Initially, the co-doped ceria of composition Ce0.9Zr0.05Y0.05O2−δ (CZY) was synthesized by using the conventional solid-state reaction method. Then, the ceramic was mixed with commercial silver powders using a ball milling process and subsequently uniaxially pressed and sintered to form the disk-shaped cermet. The dense membrane was finally formed via the infiltration of molten salts into the porous cermet supports. At high temperatures (700–850 °C), the membranes exhibit CO2/N2 and O2/N2 permselectivity and a high permeation flux under different CO2 concentrations in the feed and sweeping gas flow rates. The observed permeation properties make its use viable for CO2 valorization via the oxy-CO2 reforming of methane, wherein both CO2 and O2 permeated gases were effectively utilized to produce hydrogen-rich syngas (H2 + CO) through a catalytic membrane reactor arrangement at different temperatures ranging from 700 to 850 °C. The effect of the ceramic filler in the cermet is discussed, and continuous permeation testing, up to 115 h, demonstrated the membrane’s superior chemical and thermal stability by confirming the absence of any chemical interaction between the material and the carbonates as well as the absence of significant sintering concerns with the pure silver.

Dehydration by Pervaporation of an Organic Solution for the Direct Synthesis of Diethyl Carbonate

Pervaporation has been a central subject in the research community within the scope of the further development of energy- and cost-efficient alternatives to conventional liquid–liquid separation technologies. The potential eligibility of four commercial membranes (ZEBREX ZX0, PERVAPTM 4155-80, PERVAPTM 4100, PERVAPTM 4101) for use in an integrated dehydration application of a diethyl carbonate/water/ethanol mixture by pervaporation was assessed experimentally. The impact of feed concentration, operating temperature, pressure, and sweep gas flow rate on membrane separation performance, including permeation flux, permeate quality, selectivity, and permeance, was thoroughly investigated. Applying the ZX0 membrane delivered the best qualities of all tested membranes of the permeate stream, with a water concentration of mostly >98%. In comparing the water flux, the ZX0 membrane remained reasonably competitive with the polymer membranes. Furthermore, the sweep gas volume flow rate and the operating temperature were identified as influencing the flux significantly but not the product composition. At the same time, the feed concentration of water also influenced the water purity within the permeate. The experiments were monitored with a partial least squares model, allowing a quick assessment of obtained samples while delivering accurate results.

Understanding the role of flux chamber configuration in the measurement of VOC emissions from porous media

The accurate quantification of volatile organic compound (VOC) emission rates from porous media to the air is a challenging problem, as measurements are affected by the chemical and physical characteristics of the porous media, and the operating parameters of the sampling device itself. The main objective of this study is to investigate how flux chamber (the most commonly used sampling device) configurations influence emission rate measurement from three selected porous media. Various parameters were studied, including sweep air flow rate, presence of a mixing fan, headspace volume and thickness of media. Controlled experiments focused on the behaviour of two VOCs commonly found in area sources: acetic acid and 1-butanol. Sweep gas flow rate emerged as the most influential factor, inducing turbulence and dilution over porous media surfaces and impacting emission rate measurements more significantly than headspace volume and fan installation. Variations in porous media properties also affected mass transfer, with emissions from coco coir showing higher mass transfer as its porosity and particle size facilitated gas transportation. While behaviour of acetic acid emission through the media supported the diffusion theory, emission of 1-butanol was affected by a combination of factors, highlighting the role of both diffusive and advective transport mechanisms. Understanding how flux chamber setups and porous media properties influence emission rates is crucial for accurately interpreting data. This knowledge also guides the design of studies, especially when investigating complex sources like biosolids and organic-amended soil.

Optimization of Membrane Condenser Process with PTFE Hollow Fiber Membrane.

A membrane condenser (MC) is a novel membrane separation technology that utilizes the hydrophobic nature of porous membranes to capture water vapor from humid gas. Factors such as temperature, pressure, flow rate, and gas composition entering the membrane condenser play a crucial role in water recovery efficiency. This study utilized hydrophobic polytetrafluoroethylene (PTFE) hollow fiber membranes to create multiple identical membrane modules. This research investigated the impact of temperature, flow rate, pressure on the intake side, gas flow on the cooling side, membrane area, and other variables on the performance of the membrane condenser process. This study compared water extraction efficiency under different conditions, focusing on feed flow temperature and sweeping flow. Results showed that at a temperature of 60 °C, the water recovery rate was 24.7%, while a sweep gas flow rate of 4 L/min resulted in a recovery rate of 22.7%. The efficiency of the membrane condenser decreased with higher feed flow rates but increased with larger membrane areas. A proportional relationship between inlet flow and membrane area was observed, suggesting an optimal range of 0.51-0.67 cm/s for both parameters. These findings offer valuable insights for the practical implementation of hydrophobic membrane-based membrane condenser technology.

Mitigated CH4 release of anaerobic waste fermentation is enabled through effluent degassing system equipped with a polydimethylsiloxane membrane contactor

In this study, first, a fed-batch biogas fermenter was established using anaerobic digester sludge treating secondary sludge from a municipal wastewater treatment plant and operated for 120 days on glycerol as the sole substrate. Then, the prefiltered effluent of the anaerobic digester unit was loaded subsequently into a stirred-tank coupled with a hollow-fibre, polydimethylsiloxane (PDMS) gas-liquid membrane contactor and a dissolved methane sensor for studying the gas recovery process under continuous biogas supply, consisting of CH4 and CO2 in different proportions (70/30 CH4/CO2 vol.%; 50/50 CH4/CO2 vol.%; 30/70 CH4/CO2 vol.%.). Experiments showed that besides the actual composition of the internal biogas, the ratio (0.5–2) of sweep gas (N2) and effluent (liquid) volumetric flow rates (G/L) could be a crucial operating factor with influence on the degassing efficiency attainable by the 1 m2 PDMS membrane module. Results were compared to the performance of the same PDMS membrane module working with synthetic anaerobic digester effluents, indicating the dissolved methane recoveries observed with the synthetic effluents (>50 %) considerably surpassed those with the real effluent (<20 %) where the dissolved methane concentrations, at G/L of 1, were in the range of 12.4 to 17.3 mg L−1.

Mechanical ventilation during extracorporeal membrane oxygenation support - New trends and continuing challenges.

The impact of mechanical ventilation on the survival of patients supported with veno-venous extracorporeal membrane oxygenation (V-V ECMO) due to severe acute respiratory distress syndrome (ARDS) remains still a focus of research. Recent guidelines, randomized trials, and registry data underscore the importance of lung-protective ventilation during respiratory and cardiac support on ECMO. This approach includes decreasing mechanical power delivery by reducing tidal volume and driving pressure as much as possible, using low or very low respiratory rate, and a personalized approach to positive-end expiratory pressure (PEEP) setting. Notably, the use of ECMO in awake and spontaneously breathing patients is increasing, especially as a bridging strategy to lung transplantation. During respiratory support in V-V ECMO, native lung function is of highest importance and adjustments of blood flow on ECMO, or ventilator settings significantly impact the gas exchange. These interactions are more complex in veno-arterial (V-A) ECMO configuration and cardiac support. The fraction on delivered oxygen in the sweep gas and sweep gas flow rate, blood flow per minute, and oxygenator efficiency have an impact on gas exchange on device side. On the patient side, native cardiac output, native lung function, carbon dioxide production (VCO2), and oxygen consumption (VO2) play a role. Avoiding pulmonary oedema includes left ventricle (LV) distension monitoring and prevention, pulse pressure >10mm Hg and aortic valve opening assessment, higher PEEP adjustment, use of vasodilators, ECMO flow adjustment according to the ejection fraction, moderate use of inotropes, diuretics, or venting strategies as indicated and according to local expertise and resources. Understanding the physiological principles of gas exchange during cardiac support on femoro-femoral V-A ECMO configuration and the interactions with native gas exchange and haemodynamics are essential for the safe applications of these techniques in clinical practice. Proning during ECMO remains to be discussed until further data is available from prospective, randomized trials implementing individualized PEEP titration during proning.

Highly efficient and stable hydrogen permeable membrane reactor for propane dehydrogenation

The synthesis of SAPO-34 hollow fiber membranes employs the ball-milling assistant method to enhance membrane yield and quality. These membranes are then combined with CrOx/Al2O3 catalyst to create a packed bed membrane reactor (PBMR) for propane dehydrogenation (PDH). The study investigates the impact of operating temperatures, weight hourly space velocities (WHSV), and sweep gas flow rates on the SAPO-34 zeolite membrane reactor's performance, comparing it to a traditional packed bed reactor (PBR). The removal of hydrogen from the reaction side significantly improves propane conversion, surpassing thermodynamic equilibrium. In PBMR, propylene selectivity slightly exceeds that in PBR, influenced by side reactions like hydrogenolysis and cracking after hydrogen removal. Furthermore, the SAPO-34 zeolite membrane reactor undergoes a prolonged stability test with frequent regeneration using pure propane as feedstock to simulate industrial conditions. It exhibits consistent performance over 120 regeneration cycles within 240 h, maintaining similar H2 permeability and H2/C3H8 selectivity as the fresh membrane post long-term testing.

Experimental investigation on utilization of Sesbania grandiflora residues through thermochemical conversion process for the production of value added chemicals and biofuels

All the countries in the world are now searching for renewable, environmentally friendly alternative fuels due to the shortage and environmental problems related with the usage of conventional fuels. The cultivation of cereal and noncereal crops through agricultural activities produces waste biomasses, which are being evaluated as renewable and viable fossil fuel substitutes. The thermochemical properties and thermal degradation behavior of Sesbania grandiflora residues were investigated for this work. A fluidized bed reactor was used for fast pyrolysis in order to produce pyrolysis oil, char and gas. Investigations were done to analyze the effect of operating parameters such as temperature (350–550 °C), particle size (0.5–2.0 mm), sweeping gas flow rate (1.5–2.25 m3/h). The maximum of pyrolysis oil (44.7 wt%), was obtained at 425 °C for 1.5 mm particle size at the sweep gas flow rate of 2.0 m3/h. Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry methods were used to examine the composition of the pyrolysis oil. The pyrolysis oil is rich with aliphatic, aromatic, phenolic, and some acidic chemicals. The physical characteristics of pyrolysis oil showed higher heating value of 19.76 MJ/kg. The char and gaseous components were also analyzed to find its suitability as a fuel.

Assessing the Viability of GeO2/GeO Redox Thermochemical Cycle for Converting CO2 into Solar Fuels

The solar thermochemical process of splitting CO2, known as CDS, is studied here using a redox cycle involving GeO2/GeO. The required thermodynamic data for a second-law-efficiency analysis is obtained from the HSC Chemistry software. The goal of this study is to investigate how different parameters, such as the operating temperatures and molar flow rate of the inert sweep gas, as well as the inclusion of separation units, heat exchangers, heaters, and coolers, can affect the solar-to-fuel energy conversion efficiency of the GeO2/GeO cycle. All calculations assume a constant gas-to-gas heat recovery effectiveness of 0.5. The analysis shows that the solar-to-fuel energy conversion efficiency is lower at a thermal reduction temperature of 1600 K (11.9%) compared to 2000 K. This is because high energy duties are required for heater-2, heater-3, and separator-1 due to the need for a higher inert gas flow rate. After conducting a comparative analysis of the three CDS cycles, it can be inferred that the GeO2/GeO cycle exhibits a significantly higher solar-to-fuel energy conversion efficiency in comparison to the ZnO/Zn and SnO2/SnO cycles across all thermal reduction temperatures. According to the comparison, it is confirmed that the GeO2/GeO CDS cycle can achieve a reasonably high solar-to-fuel energy conversion efficiency of 10% at less than 1600 K. On the other hand, ZnO/Zn and SnO2/SnO CDS cycles require a thermal reduction temperature of more than 1850 K to achieve a solar-to-fuel energy conversion efficiency of 10%.

Effects of dead volume and inert sweep gas flow on photocatalytic hydrogen evolution over Pt/TiO2

In this study, the effects of dead volume and sweep gas flow rate on photocatalytic hydrogen production over Pt/TiO2 were examined to determine their possible impact on hydrogen production rates. Five different dead volumes (15, 45, 75, 190, 425 ml) under constant reaction solution and interfacial area experimented by using custom made reactors. It was found that higher dead volumes in the gas phase inversely affect the measured hydrogen production. The difference between highest and lowest H2 production rates (at steady state) among five dead volumes is found as 30 μmol/h gcat which is 24% of the highest rate. On the other hand, the difference due to sweep gas flow rates (15, 30, 45 ml/min Ar) was not as significant. It was concluded from these results that measured hydrogen production rate in photocatalytic systems depend strongly on the reactor size through gas phase dead volume and operational factors like sweep gas flowrate. The difference between highest and lowest hydrogen production rates for different dead volumes or sweep gas flow rates is too great to ignore when the average photocatalytic hydrogen production levels (∼500 μmol/h gcat) in the literature are considered. Uncertainties associated with these factors together with well-known difficulties in measurement (or reporting) of the amount of energy and the characteristics of light absorbed by the reaction solution make the comparison of results from different studies impossible. The results of this study confirm the need for standard protocols of measurement and testing in the photocatalysis field in general, and photocatalytic hydrogen production particularly.

Serum Bicarbonate Levels Among Patients on Venovenous Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome With and Without Kidney Replacement Therapy

OBJECTIVES: For patients with acute respiratory distress syndrome (ARDS) receiving venovenous extracorporeal membrane oxygenation (ECMO) who develop acute kidney injury (AKI) requiring kidney replacement therapy (KRT), the inability to renally compensate for respiratory acidosis could result in increased sweep gas flow to normalize arterial pH. Our objective was to examine the relationship of serum bicarbonate levels, arterial pH, sweep gas flow, and Paco 2. DESIGN: This is a retrospective cohort study. We compared patients who received KRT while undergoing venovenous ECMO to patients who did not. SETTING: Vanderbilt University Medical Center, February 2019 to February 2022. PATIENTS: We examined data from adult patients receiving venovenous ECMO for ARDS. INTERVENTIONS: Values for serum bicarbonate, arterial pH, Paco 2, and sweep gas flow were collected daily from time of cannulation until the earlier of decannulation, 30 days, or death. MEASUREMENTS AND MAIN RESULTS: Of the 126 patients included, 53 (42.1%) received KRT and 73 (57.9%) did not. In patients who received KRT, mean serum bicarbonate levels remained between 22 and 28 mmol/L throughout the study period. Patients who did not receive KRT experienced an increase in mean serum bicarbonate levels over time up to 40 mmol/L (mean difference = –4.4 mmol/L [95% CI, –6.3 to –2.5 mmol/L]; p &lt; 0.0001). Mean values for Paco 2 (–5.2 [95% CI, –8.8 to –1.7]; p = 0.004) and pH (–0.03 [95% CI, –0.03 to –0.02]; p &lt; 0.0001) were lower in patients who received KRT than in patients who did not, despite higher sweep gas flow rates in patients who received KRT than in patients who did not (mean difference = 1.5 [95% CI, 0.8–2.3]; p &lt; 0.001). CONCLUSIONS: ARDS patients on venovenous ECMO with preserved kidney function experience an increase in bicarbonate concentration over time, compared to patients with AKI on KRT. Whether this increase in bicarbonate concentration increases pH, decreases sweep gas flow requirements, and facilitate weaning from venovenous ECMO requires examination in future research.

Evaluation of CO2 removal rate of ECCO2R for a renal replacement therapy platform in an experimental setting.

A critical parameter of extracorporeal CO2 removal (ECCO2R) applications is the CO2 removal rate (VCO2). Low-flow venovenous extracorporeal support with large-size membrane lung remains undefined. This study aimed to evaluate the VCO2 of a low-flow ECCO2R with large-size membrane lung using a renal replacement therapy platform in an experimental animal model. Twelve healthy pigs were placed under mechanical ventilation and connected to an ECCO2R-CRRT system (surface area = 1.8 m2; OMNIset®, BBraun, Germany). Respiratory settings were reduced to induce two degrees of hypercapnia. VCO2 was recorded under different combinations of PaCO2 (50-69 or 70-89 mm Hg), extracorporeal blood flow (ECBF; 200 or 350 mL/min), and gas flow (4, 6, or 10 L/min). VCO2 increased with ECBF at all three gas flow rates. In severe hypercapnia, the increase in sweep gas flow from 4 to 10 L/min increased VCO2 from 86.38 ± 7.08 to 96.50 ± 8.71 mL/min at an ECBF of 350 mL/min, whereas at ECBF of 200 mL/min, any increase was less effective. But in mild hypercapnia, the increase in sweep gas flow result in significantly increased VCO2 at two ECBF. VCO2 increased with PaCO2 from 50-69 to 70-89 mm Hg at an ECBF of 350 mL/min, but not at ECBF of 200 mL/min. Post-membrane lung PCO2 levels were similar for different levels of premembrane lung PCO2 (p = 0.08), highlighting the gas exchange diffusion efficacy of the membrane lung in gas exchange diffusion. In severe hypercapnia, the reduction of PaCO2 elevated from 11.5% to 19.6% with ECBF increase only at a high gas flow of 10 L/min (p < 0.05) and increase of gas flow significantly reduced PaCO2 only at a high ECBF of 350 mL/min (p < 0.05). Low-flow venovenous extracorporeal ECCO2R-CRRT with large-size membrane lung is more efficient with the increase of ECBF, sweep gas flow rate, and the degree of hypercapnia. The influence of sweep gas flow on VCO2 depends on the ECBF and degree of hypercapnia. Higher ECBF and gas flow should be chosen to reverse severe hypercapnia.

A CFD model of natural gas steam reforming in a catalytic membrane reactor: Effect of various operating parameters on the performance of CMR

The use of hydrogen as an energy carrier has increased for reasons related to its environmentally friendly characteristics. The most common and low-cost method of producing hydrogen from natural gas (or CH4) is the steam reforming process. The 2-D axisymmetric catalytic membrane reactor (CMR) model is developed for pure hydrogen production from real natural gas (NG) using a Pd–Ru membrane with a Ni/Al2O3 catalyst. In this paper, a CFD model is prepared to investigate the performance of a catalytic membrane reactor through natural gas conversion and hydrogen production under various operation parameters, i.e., temperature of reaction in the range of 600, 700, 800, 900, and 1000 K, gas hourly space velocity GHSV with a range of 500, 700, 1000, 2000, and 3000 h−1, and sweep gas flow rate (Re No.) 1, 50, 100, 150, and 250. The results of the simulation show that the CMR exhibits a high permeation rate of hydrogen on the permeate side (tube side) and achieves a high methane conversion rate of approximately 99.9 % at 1000 K on the retentate side. The hydrogen flux exhibits a decline as the temperature increases from 900 to 1000 K, despite the achievement of complete (NG) conversion. Hence, it can be concluded that the performance of the catalytic membrane reactor (CMR) process exhibits a pattern of increase when the other parameters, such as (GHSV) and (Re.No.), are increased.

Catalytic upgrading of biomass pyrolysis vapors for selective production of phenolic monomers over metal oxide modified alumina catalysts

This study investigates the catalytic vapor phase upgrading of sawdust to produce improved biocrude enriched in phenolic monomers. Various mixed metal oxide catalysts (MgO, CuO, Bi2O3, NiO, ZnO supported on Al2O3) were screened to determine the product composition. Further, the effect of different process parameters such as temperature (350 – 600 °C), metal oxide loadings (0 – 20 wt%), catalyst to biomass ratios (1:1–1:6), sweeping gas flow rates (0 – 15 LPH) were studied in terms of biocrude composition. Under non-catalytic conditions, maximum biocrude yields (∼39%) were obtained at an optimum temperature of 550 °C. The biocrude composition varied significantly with the type of metal oxide in which MgO and CuO produced higher amounts of phenolics (∼58%). Increasing MgO loading (5–20 wt%) and higher catalyst to biomass ratios (1:1) resulted in enhanced hydrocarbon yields to ∼15%. Premixing of biomass and catalyst in a fixed bed arrangement resulted in enhanced hydrocarbons/aromatics with simultaneous reduction in the phenolic content.

Recent Advances in Bimetallic Catalysts for Methane Steam Reforming in Hydrogen Production: Current Trends, Challenges, and Future Prospects.

As energy demand continues to rise and the global population steadily grows, there is a growing interest in exploring alternative, clean, and renewable energy sources. The search for alternatives, such as green hydrogen, as both a fuel and an industrial feedstock, is intensifying. Methane steam reforming (MSR) has long been considered a primary method for hydrogen production, despite its numerous advantages, the activity and stability of the conventional Ni catalysts are major concerns due to carbon formation and metal sintering at high temperatures, posing significant drawbacks to the process. In recent years, significant attention has been given to bimetallic catalysts as a potential solution to overcome the challenges associated with methane steam reforming. Thus, this review focuses on the recent advancements in bimetallic catalysts for hydrogen production through methane steam reforming. The review explores various aspects including reactor type, catalyst selection, and the impact of different operating parameters such as reaction temperature, pressure, feed composition, reactor configuration, and feed and sweep gas flow rates. The analysis and discussion revolve around key performance indicators such as methane conversion, hydrogen recovery, and hydrogen yield.

A 3-dimentinal CFD model for simulation of an O2/N2 separation process using an industrial PIHF membrane module for N2 enrichment

In this research, simulation of an O2/N2 membrane separation process for N2 enrichment using an industrial polyimide hollow fiber (PIHF) membrane module was performed based on finite element method. A 3-dimensional (3D) model was used to simulate the mass transfer, convection and diffusion phenomenon in the membrane module. In order to validate the model, the simulation results were compared with the industrial process data, and good agreement was observed. The effects of feed molar flow rate, feed pressure, and molar flow rate of sweep gas stream on the N2 enrichment percentage were investigated. As discovered, the N2 enrichment percentage is improved by enhancing the feed pressure and sweep gas flow rate, while an increase in feed flow rate promotes a diminish in percentage of N2 enrichment. Besides the operational parameters, the influence of flow patterns (co-current and counter-current) and fiber length on the N2 enrichment in lumen side and gas molecules distribution in the membrane side of PIHF membrane module was investigated respectively. As the fiber length increased, the N2 enrichment percentage augments for both patterns due to membrane surface area increment in the PIHF membrane module, which the percentage of N2 enrichment in the countercurrent pattern was higher than co-current. Moreover, Concentration Polarization Index (CPI) was investigated to show the degree of polarization expansion along the PIHF membrane. The effect of feed molar flow rate on the concentration polarization index was investigated, which showed that concentration polarization phenomenon is reduced when feed molar flow rate enhances.

High Yield Synthesis of Green Pyrolytic Oil via Thermal Cracking of Ricinoleic Acid Methyl Ester

AbstractCastor oil has the potential to be a renewable resource for the synthesis of high‐value‐added chemicals. This work focuses on the thermal cracking of ricinoleic acid methyl esters (RAME), the major component of castor oil in a micro fixed bed reactor that was used to produce methyl undecenoate (MU) and heptaldehyde (HEP). MU and HEP have wide applications in polymers, cosmetics, and drug industries. The effect of flow rate, sweeping gas flow rate, preheating and reaction temperatures were examined briefly. Thermal cracking of RAME at a preheating temperature of 350 °C and reaction temperatures of 550 °C, produced high yields of MU and HEP at 46.7 and 27.3 wt.% respectively. The increase in sweep flow rate from 15 ml min−1 to 25 ml min−1 enhanced the production of pyrolytic oil yield to 92.6 wt.%. Density functional theory (DFT) was performed to examine the experimental results and distribution of the products involved in the dissociation of RAME. Assuming C−C bond scission followed by the cleavage of the OH bond, the reaction energy of MU and HEP thermal cracking is computed using DFT. This research may provide an alternative pathway to produce important chemicals from castor oil for upscaling and process development for the industry.

XPS™ Jensen lung as a low-cost, high-fidelity training adjunct to ex-vivo lung perfusion.

Ex vivo lung perfusion (EVLP) enables lung resuscitation before transplantation, and training is key, particularly in low-volume settings. To enable technique refinement and continuing education, we sought to demonstrate the value of a low-cost, high-fidelity EVLP simulator that would allow reproducible clinical scenarios. In partnership with our EVLP manufacturer, we utilized the XPS™ Jensen Lung with our clinical system. The Jensen Lung has two simulated lung bladders and an in-line polymethylpentene fiber oxygenator. It allows titration of ventilator support which aids in accurate clinical simulation. For simulations, blood gases (BGs) were obtained and compared with integrated in-line perfusate gas monitors (PGMs). PaO2 , PCO2 , and pH were measured and compared. The PGM and BG values were not significantly different throughout the range of FiO2 and sweep gas flow rates evaluated. The "delta" PaO2 was measured between LA and PA and did not show any change between approaches. The pH measurement between BG and PGM was not significantly different. The XPS™ Jensen Lung simulator allows for a high-fidelity simulator of clinical EVLP. The correlation of the PGM and the BG measurement of the PaO2 and pH allow for a low-cost simulation, as the PGMs are in line in the circuit, and enable real-time tracking of perfusate gas parameters with the PGM. Implementation of a standardized clinical EVLP training program allows the maintenance of technique and enables clinical simulation training without the need for costly animal perfusions and the use of multiple BG measurements.

Experimental investigation on reactivation characteristics of liquid–metal heat pipes after hydrogen inactivation

The use of a hydrogen window provides an effective way for liquid–metal heat pipes (LMHPs) to prevent hydrogen inactivation when operated in a hydrogen-containing atmosphere. This work experimentally investigates the effects of various operational conditions on the reactivation characteristics of LMHPs after hydrogen inactivation. Theoretical analysis and sensitivity analysis are conducted to enhance our understanding and optimize reactivation operations. The results indicate that a slope-shaped distribution of hydrogen buffer enable faster reactivation compared to a near-column shape. A sweep-gas flow rate in 200 mL/min is preferred under test conditions, when both the reactivation time and the pure N2 consumption rate are considered. The working temperature significantly affects the reactivation time, as higher temperatures accelerate the NaH decomposition and increase the hydrogen permeability of hydrogen window. The varying of pressure and preheating temperature of sweep gas under test conditions just have little influence on the reactivation time. In practical conditions, vacuum operations are not recommended due to its extremely low hydrogen-removal rate.

Thermocatalytic pyrolysis of agriculture waste biomass for the production of renewable fuels and chemicals

ABSTRACT The present work highlights the thermocatalytic pyrolysis of three different waste biomasses (Groundnut Stalk, Indian Rosewood, and Rice Straw) using meso and microporous catalysts for the effective conversion to fuels and chemicals. Thermocatalytic pyrolysis was found to be highly significant under optimum conditions (Temperature = 500°C, Heating rate = 90°C/min, Biomass particle size = 0.4 mm, and Sweeping gas flow rate = 100 mL/min). All the synthesized catalysts (KIT-6, NbKIT-6, and ZIF-8) were found to be highly efficient, and the maximum liquid yield was observed at 20 wt% of catalyst loading, i.e. 49.35% (KIT-6); 56.57% (NbKIT-6); and 52.74% (ZIF-8), respectively. The results revealed that compared to KIT-6, the maximum liquid yield was observed with NbKIT-6 catalyst i.e. 56.57% (Groundnut Stalk); 58.45% (Indian Rosewood); and 57.57% (Rice Straw), respectively. The proposed strategy will be highly economical and sustainable and the selected biomass could be a promising alternative and renewable energy source.