scholarly journals REACTION RATES FOR HIGH-TEMPERATURE AIR

1966 ◽  
Author(s):  
M.L. Carnicom
Keyword(s):  
High Temperature ◽  
Reaction Rates

scholarly journals Effect of ball collision direction on a wet mechanochemical reaction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takahiro Kozawa ◽  
Kayo Fukuyama ◽  
Kizuku Kushimoto ◽  
Shingo Ishihara ◽  
Junya Kano ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Reaction Rates ◽  
Tangential Component ◽  
Normal Direction ◽  
Mechanochemical Reaction ◽  
Precipitation Mechanism ◽  
The Impact ◽  
Mechanochemical Reactions ◽  
Ball Motion

AbstractMechanochemical reactions can be induced in a solution by the collision of balls to produce high-temperature and high-pressure zones, with the reactions occurring through a dissolution–precipitation mechanism due to a change in solubility. However, only a fraction of the impact energy contributes to the mechanochemical reactions, while the rest is mainly consumed by the wear of balls and the heat generation. To clarify whether the normal or tangential component of collisions makes a larger contribution on the reaction, herein we studied the effect of collision direction on a wet mechanochemical reaction through combined analysis of the experimental reaction rates and simulated ball motion. Collisions of balls in the normal direction were found to contribute strongly to the wet mechanochemical reaction. These results could be used to improve the synthesis efficiency, predict the reaction, and lower the wear in the wet mechanochemical reactions.

Using Advance Acid Fracturing Design to Increase the Production Efficiency in a HPHT Reservoir: A Success Story from Southern Mexico

2021 ◽  
Author(s):  
Frank Figueroa ◽  
Gustavo Mejías ◽  
José Frías ◽  
Bonifacio Brito ◽  
Diana Velázquez ◽  
...  
Keyword(s):  
High Temperature ◽  
Laboratory Tests ◽  
Reaction Rates ◽  
Gas Production ◽  
Carbonate Reservoir ◽  
Fluid Distribution ◽  
Acid Etching ◽  
Southern Mexico ◽  
Acid Fracturing ◽  
Fluid Systems

Abstract Enhanced hydrocarbon production in a high-pressure/high-temperature (HP/HT) carbonate reservoir, involves generating highly conductive channels using efficient diversion techniques and custom-designed acid-based fluid systems. Advanced stimulation design includes injection of different reactive fluids, which involves challenges associated with controlling fluid leak-off, implementing optimal diversion techniques, controlling acid reaction rates to withstand high-temperature conditions, and designing appropriate pumping schedules to increase well productivity and sustainability of its production through efficient acid etching and uniform fluid distribution in the pay zone. Laboratory tests such as rock mineralogy, acid etching on core samples and solubility tests on formation cuttings were performed to confirm rock dissolving capability, and to identify stimulation fluids that could generate optimal fracture lengths and maximus etching in the zone of interest while corrosion test was run to ensure corrosion control at HT conditions. After analyzing laboratory tests results, acid fluid systems were selected together with a self-crosslinking acid system for its diversion properties. In addition, customized pumping schedule was constructed using acid fracturing and diverting simulators and based on optimal conductivity/productivity results fluid stages number and sequence, flow rates and acid volumes were selected. The engineered acid treatment generated a network of conductive fractures that resulted in a significant improvement over initial production rate. Diverting agent efficiency was observed during pumping treatment by a 1,300 psi increase in surface pressures when the diverting agent entered the formation. Oil production increased from 648.7 to 3105.89 BPD, and gas production increased from 4.9 to 26.92 MMSCFD. This success results demonstrates that engineering design coupled with laboratory tailor fluids designs, integrated with a flawless execution, are the key to a successful stimulation. This paper describes the details of acidizing technique, treatment design and lessons learned during execution and results.

scholarly journals Synthesis of highly effective stabilized CaO sorbents via a sacrificial N-doped carbon nanosheet template

2019 ◽  
Vol 7 (15) ◽  
pp. 9173-9182 ◽  
Author(s):  
Ke Wang ◽  
Peter T. Clough ◽  
Pengfei Zhao ◽  
Edward J. Anthony
Keyword(s):  
High Temperature ◽  
High Capacity ◽  
Reaction Rates ◽  
Good Stability ◽  
Highly Effective ◽  
Rapid Reaction

Highly macroporous MgO-stabilized CaO nanosheets with rapid reaction rates, high capacity, and good stability for high-temperature CO2 capture.

Review of Coal-to-Synthetic Natural Gas (SNG) Production Methods and Modeling of SNG Production in an Entrained-Flow Gasifer

2016 ◽  
Author(s):  
Xijia Lu ◽  
Ting Wang
Keyword(s):  
High Temperature ◽  
Computational Model ◽  
Catalytic Reaction ◽  
Reaction Rates ◽  
Sensitivity Study ◽  
Synthetic Natural Gas ◽  
Entrained Flow ◽  
Methanation Reaction ◽  
Gasification Process ◽  
Entrained Flow Gasifier

In this paper, the coal-to-synthetic natural gas (SNG) technologies have been reviewed. Steam-oxygen gasification, hydrogasification, and catalytic steam gasification are the three major gasification processes used in coal-to-SNG production. So far, only the steam-oxygen gasification process is commercially proven by installing a catalytic methanation reactor downstream of the gasification process after syngas is produced, cleaned, and shifted to achieve an appropriate H2/CO ratio for methanation reaction. This process is expensive, less efficient, and time consuming. Ideally, it will be more effective and economic if methanation could be completed in an once-through entrained-flow gasifier. Technically, this idea is challenging because an effective gasification process is typically operated in a high-pressure and high-temperature condition, which is not favorable for methanation reaction, which is exothermic. To investigate this idea, a computational model is established and a sensitivity study of methanation reactions with and without catalysts are conducted in this study. In modeling the methanation process in a gasifier, correct information of the reaction rates is extremely important. Most of known methanation reaction rates are tightly linked to the catalysts used. Since the non-catalytic reaction rates for methanation are not known in a gasifer and the issues are compounded by the fact that inherent minerals in coal ashes can also affect the methanation kinetics, modeling of methanation in an entrained-flow gasifier becomes very challenging. Considering these issues, instead of trying to obtain the correct methnation reaction rate, this study attempts to use computational model as a convenient tool to investigate the sensitivity of methane production under a wide range methanation reaction rates with and without catalysts. From this sensitivity study, it can be learned that the concept of implementing direct methanation in a once-through entrained-flow gasifier may not be attractive due to competitions of other reactions in a high-temperature environment. The production of SNG is limited to about 18% (vol) with catalytic reaction with a pre-exponential factor A in the order of 107. A further increase of the value of A to 1011 doesn’t result in more production of SNG. This SNG production limit could be caused by the high-temperature and short residence time (3–4 seconds) in the entraind-flow gasifier.

Thermonuclear-Reaction Rates at High Temperature

1970 ◽  
Vol 2 (6) ◽  
pp. 2041-2049 ◽  
Author(s):  
Georges Michaud ◽  
William A. Fowler
Keyword(s):  
High Temperature ◽  
Reaction Rates ◽  
Thermonuclear Reaction

Ignition in the supersonic hydrogen/air mixing layer with reduced reaction mechanisms

1996 ◽  
Vol 322 ◽  
pp. 275-296 ◽  
Author(s):  
H. G. Im ◽  
B. T. Helenbrook ◽  
S. R. Lee ◽  
C. K. Law
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Temperature Regime ◽  
Characteristic Temperature ◽  
Mixing Layer ◽  
Reaction Rates ◽  
Thermal Runaway ◽  
Ignition Process ◽  
High Temperature Regime ◽  
Air Mixing

Asymptotic analysis of ignition within the supersonic hydrogen/air mixing layer is performed using reduced mechanisms. Two distinct reduced mechanisms for the high-temperature and the low-temperature regimes are used depending on the characteristic temperature of the reaction zone relative to the crossover temperature at which the reaction rates of the H + 02 branching and termination steps are equal. Each regime further requires two distinct analyses for the hot-stream and the viscous-heating cases, depending on the relative dominance of external and internal ignition energy sources. These four cases are analysed separately, and it is shown that the present analysis successfully describes the ignition process by exhibiting turning point or thermal runaway behaviour in the low-temperature regime, and radical branching followed by thermal runaway in the high-temperature regime. Results for the predicted ignition distances are then mapped out over the entire range of the parameters, showing consistent behaviour with the previous one-step model analysis. Furthermore, it is demonstrated that ignition in the low-temperature regime is controlled by a larger activation energy process, so that the ignition distance is more sensitive to its characteristic temperature than that in the high-temperature regime. The ignition distance is also found to vary non-monotonically with the system pressure in the manner of the well-known hydrogen/oxygen explosion limits, thereby further substantiating the importance of chemical chain mechanisms in this class of chemically reacting boundary layer flows.

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