scholarly journals CFD Simulation of Hydrogen Generation and Methane Combustion Inside a Water Splitting Membrane Reactor

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7175
Author(s):  
Te Zhao ◽  
Chusheng Chen ◽  
Hong Ye
Keyword(s):  
Water Splitting ◽  
Flow Rate ◽  
Membrane Reactor ◽  
Gas Flow ◽  
Cfd Simulation ◽  
Hydrogen Generation ◽  
Methane Combustion ◽  
Inlet Temperature ◽  
Hydrogen Yield ◽  
Gas Flow Rate

Hydrogen production from water splitting remains difficult due to the low equilibrium constant (e.g., Kp ≈ 2 × 10−8 at 900 °C). The coupling of methane combustion with water splitting in an oxygen transport membrane reactor can shift the water splitting equilibrium toward dissociation by instantaneously removing O2 from the product, enabling the continuous process of water splitting and continuous generation of hydrogen, and the heat required for water splitting can be largely compensated for by methane combustion. In this work, a CFD simulation model for the coupled membrane reactor was developed and validated. The effects of the sweep gas flow rate, methane content and inlet temperature on the reactor performance were investigated. It was found that coupling of methane combustion with water splitting could significantly improve the hydrogen generation capacity of the membrane reactor. Under certain conditions, the average hydrogen yield with methane combustion could increase threefold compared to methods that used no coupling of combustion. The methane conversion decreases while the hydrogen yield increases with the increase in sweep gas flow rate or methane content. Excessive methane is required to ensure the hydrogen yield of the reactor. Increasing the inlet temperature can increase the membrane temperature, methane conversion, oxygen permeation rate and hydrogen yield.

scholarly journals NO Separation Characteristics in Integrated Electromigration Membrane Reactor

2020 ◽  
Vol 10 (15) ◽  
pp. 5071
Author(s):  
Zuwu Wang ◽  
Guifen Shen
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Total Mass ◽  
Membrane Reactor ◽  
Gas Flow ◽  
Separation Efficiency ◽  
Discharge Voltage ◽  
Gas Flow Rate

An integrated electromigration membrane absorption method has been proposed for the separation of NO from simulated mixed gas. The experiments were conducted to investigate the effect of discharge voltage, gas flow rate, inlet concentrations, and absorbents on the NO separation efficiency and total mass transfer coefficient in the integrated electromigration membrane reactor. The experimental results demonstrated that the NO separation efficiency and total mass transfer coefficient increased with the increase in the applied discharge voltage of the integrated electromigration membrane reactor. Regardless of discharge or not, the separation efficiency of NO continuously decreased with the increase in the gas flow rate and inlet concentration of NO in the experimental process. The total mass transfer coefficient of NO increased first and then decreased with an increase in the gas flow rate, while it decreased with an increase in NO inlet concentration. Compared with the membrane absorption without discharge voltage under the condition tested, at a discharge voltage of 18kV, the NO separation efficiency and the total mass transfer coefficient increased by 48.7% and 9.7 times, respectively.

Simulation of Catalytic Dehydrogenation of Cyclohexane in Zeolite Membrane Reactor

2009 ◽  
Vol 7 (1) ◽  
Author(s):  
Shashi Kumar ◽  
Tanvi Gaba ◽  
Surendra Kumar
Keyword(s):  
Flow Rate ◽  
Membrane Reactor ◽  
Gas Flow ◽  
Fixed Bed ◽  
Full Length ◽  
Zeolite Membrane ◽  
Hybrid Reactor ◽  
Gas Flow Rate ◽  
Dehydrogenation Of Cyclohexane ◽  
Type Zeolite

A mathematical model is presented to investigate the performance of tubular catalytic membrane reactor for dehydrogenation of cyclohexane using a FAU type zeolite membrane. The empirical correlations for the permeance of cyclohexane, benzene and hydrogen through FAU type zeolite membrane as a function of temperature have been developed. Three reactor configurations have been considered: conventional fixed bed, full length membrane reactor and hybrid reactor. The reactor performance has been studied in terms of conversion of cyclohexane to produce hydrogen. The observed conversions are ranked in the order: full length membrane reactor > hybrid reactor > fixed bed reactor. The simulation studies have been carried out for two feed conditions: one with hydrogen and another without hydrogen. The effect of cofeeding of hydrogen, sweep gas flow rate variation, and dilution ratio on the conversion of cyclohexane has been investigated in detail. The maximum percent increase in conversion of cyclohexane has been obtained at 473 K in hybrid as well as in membrane reactor. This temperature is also found to be optimum for sweep gas flow rate of 4.5 x 10-5 mol s-1. The conversion is observed to be suppressed by cofeeding of hydrogen and percent reduction is lowest at high temperature of 490 K in membrane reactor. The enhancement in the conversion is observed as a consequence of dilution of the feed with inert gas. The results reveal that hybrid reactor is not necessarily a better choice than the full length membrane reactor. However, at the expense of loss of reactant, hybrid reactor is better than full length membrane reactor.

CFD Simulation of Steam Ejector System in High Altitude Test (HAT) Facility

2012 ◽  
Author(s):  
Pavani Sreekireddy ◽  
T. Kishen Kumar Reddy ◽  
Venugopal Dadi ◽  
P. Bhramara
Keyword(s):  
High Altitude ◽  
Flow Rate ◽  
Gas Flow ◽  
Cfd Simulation ◽  
Reverse Flow ◽  
Design Parameters ◽  
Gas Flow Rate ◽  
Steam Ejector ◽  
Ejector System ◽  
The Given

In the present work, the performance of Steam Ejector System in High Altitude Test (HAT) facility is numerically studied, in the absence of the condenser. Steam is used as secondary fluid to eject the burnt gases into atmosphere. Experimental visualization of mixing of burnt gas and steam and subsequent flow pattern is difficult, hence numerical simulation using FLUENT was done and the resulting flow stream lines, static and total pressures, shock patterns are computed along the ejector system to understand the physics of the problem. Three burnt gas flow rates of 9.17, 27.5 and 45.8 kg/s corresponding to lower, mid and upper limits of ejection from the HAT facility with the steam flow rate of 50 kg/s from Ejector I and 130 kg/s from Ejector II are studied. This corresponds to three cases of Entrainment Ratios for each of the ejector. Results show that for a burnt gas flow rate of 27.5 and 45.8 kg/s with the given dimensions of the HAT facility provided by ASL, DRDO, the gas and steam start mixing in the converging duct, pass through the mixing tube and attains atmospheric pressure at the exit of the HAT facility. For the burnt gas flow rate of 9.17 kg/s, reverse flow is observed in the Ejector II, indicating the malfunction mode of the system for the given design parameters.

scholarly journals CFD Simulation of Syngas Combustion in a Two-Pass Oxygen Transport Membrane Reactor for Fire Tube Boiler Application

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7348
Author(s):  
Te Zhao ◽  
Chusheng Chen ◽  
Hong Ye
Keyword(s):  
Membrane Reactor ◽  
Gas Flow ◽  
Thermal Power ◽  
Oxygen Permeation ◽  
Permeation Rate ◽  
Inlet Temperature ◽  
Gas Flow Rate ◽  
Reactor Performance ◽  
Syngas Combustion ◽  
Oxygen Transport Membrane

The oxygen transport membrane reactor technology enables the stable combustion of syngas and reduction in NOx emission. Applying the syngas combustion membrane reactor to fire tube boiler can integrate oxygen separation, syngas combustion, and steam generation in a single apparatus. In this study, a CFD model for oxygen permeation and syngas combustion in a two-pass LSCoF-6428 tubular membrane reactor for fire tube boiler application was developed to study the effects of the inlet temperature, the sweep gas flow rate, and the syngas composition on the reactor performance. It is shown that the inlet temperature has a strong effect on the reactor performance. Increasing the inlet temperature can efficiently and significantly improve the oxygen permeability and the heat production capacity. A 34-times increase of oxygen permeation rate and a doubled thermal power output can be obtained when increasing the inlet temperature from 1073 to 1273 K. The membrane temperature, the oxygen permeation rate, and the thermal power output of the reactor all increase with the increase of sweep gas flow rate or H2/CO mass ratio in syngas. The feasibility of the syngas combustion membrane reactor for fire tube boiler application was elucidated.

scholarly journals A Design of Experiment Approach to Optimize Spray-Dried Powders Containing Pseudomonas aeruginosaPodoviridae and Myoviridae Bacteriophages

Viruses ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1926
Author(s):  
Emilie Tabare ◽  
Tea Glonti ◽  
Christel Cochez ◽  
Cyrille Ngassam ◽  
Jean-Paul Pirnay ◽  
...  
Keyword(s):  
Spray Drying ◽  
Flow Rate ◽  
Gas Flow ◽  
Negative Impact ◽  
Positive Impact ◽  
Inlet Temperature ◽  
Spray Dryer ◽  
Gas Flow Rate ◽  
Residual Moisture ◽  
Spray Dried

In the present study, we evaluated the effect of spray-drying formulations and operating parameters of a laboratory-scale spray-dryer on the characteristics of spray-dried powders containing two Pseudomonas aeruginosa bacteriophages exhibiting different morphotypes: a podovirus (LUZ19) and a myovirus (14-1). We optimized the production process for bacteriophage-loaded powders, with an emphasis on long-term storage under ICH (international conference on harmonization) conditions. D-trehalose-/L-isoleucine-containing bacteriophage mixtures were spray-dried from aqueous solutions using a Büchi Mini Spray-dryer B-290 (Flawil, Switzerland). A response surface methodology was used for the optimization of the spray-drying process, with the following as-evaluated parameters: Inlet temperature, spray gas flow rate, and the D-trehalose/L-isoleucine ratio. The dried powders were characterized in terms of yield, residual moisture content, and bacteriophage lytic activity. L-isoleucine has demonstrated a positive impact on the activity of LUZ19, but a negative impact on 14-1. We observed a negligible impact of the inlet temperature and a positive correlation of the spray gas flow rate with bacteriophage activity. After optimization, we were able to obtain dry powder preparations of both bacteriophages, which were stable for a minimum of one year under different ICH storage conditions (up to and including 40 °C and 75% relative humidity).

SCIENTIFIC AND ENGINEERING PRINCIPLES OF EFFICIENT FUEL USE AND ENVIRONMENTALLY FRIENDLY GAS COMBUSTION IN STOVE PLATES. PART 1. MODERN STATE-OF-THE-ART AND DIRECTIONS FOR IMPROVEMENT THE GAS BURNING IN DOMESTIC GAS COOKERS

2017 ◽  
pp. 3-18 ◽  
Author(s):  
B.S. Soroka ◽  
V.V. Horupa
Keyword(s):  
Natural Gas ◽  
Flow Rate ◽  
Gas Flow ◽  
Renewable Energy Sources ◽  
Combustion Process ◽  
Orifice Diameter ◽  
Firing Process ◽  
Gas Flow Rate ◽  
Gas Combustion ◽  
Gas Stoves

Natural gas NG consumption in industry and energy of Ukraine, in recent years falls down as a result of the crisis in the country’s economy, to a certain extent due to the introduction of renewable energy sources along with alternative technologies, while in the utility sector the consumption of fuel gas flow rate enhancing because of an increase the number of consumers. The natural gas is mostly using by domestic purpose for heating of premises and for cooking. These items of the gas utilization in Ukraine are already exceeding the NG consumption in industry. Cooking is proceeding directly in the living quarters, those usually do not meet the requirements of the Ukrainian norms DBN for the ventilation procedures. NG use in household gas stoves is of great importance from the standpoint of controlling the emissions of harmful components of combustion products along with maintenance the satisfactory energy efficiency characteristics of NG using. The main environment pollutants when burning the natural gas in gas stoves are including the nitrogen oxides NOx (to a greater extent — highly toxic NO2 component), carbon oxide CO, formaldehyde CH2O as well as hydrocarbons (unburned UHC and polyaromatic PAH). An overview of environmental documents to control CO and NOx emissions in comparison with the proper norms by USA, EU, Russian Federation, Australia and China, has been completed. The modern designs of the burners for gas stoves are considered along with defining the main characteristics: heat power, the natural gas flow rate, diameter of gas orifice, diameter and spacing the firing openings and other parameters. The modern physical and chemical principles of gas combustion by means of atmospheric ejection burners of gas cookers have been analyzed from the standpoints of combustion process stabilization and of ensuring the stability of flares. Among the factors of the firing process destabilization within the framework of analysis above mentioned, the following forms of unstable combustion/flame unstabilities have been considered: flashback, blow out or flame lifting, and the appearance of flame yellow tips. Bibl. 37, Fig. 11, Tab. 7.

On the Influence of Fluctuating Flow Rate Upon the Performance and Behaviour of Isothermal Reacting Systems

1998 ◽  
Vol 63 (6) ◽  
pp. 881-898
Author(s):  
Otakar Trnka ◽  
Miloslav Hartman
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Fluidized Bed Reactor ◽  
Computational Techniques ◽  
Continuous Stirred Tank Reactor ◽  
Gas Flow Rate ◽  
Solid Reaction ◽  
Continuous Stirred Tank ◽  
And Performance ◽  
Reacting Systems

Three simple computational techniques are proposed and employed to demonstrate the effect of fluctuating flow rate of feed on the behaviour and performance of an isothermal, continuous stirred tank reactor (CSTR). A fluidized bed reactor (FBR), in which a non-catalytic gas-solid reaction occurs, is also considered. The influence of amplitude and frequency of gas flow rate fluctuations on reactant concentrations at the exit of the CSTR is shown in four different situations.

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