Activities of Several Enzymes in Ethanol + Water at Elevated Pressure of Carbon Dioxide

2004 ◽  
Vol 49 (5) ◽  
pp. 1333-1339 ◽  
Author(s):  
Shan-Jing Yao ◽  
Yi-Xin Guan ◽  
Wei-Zhong He ◽  
Xiang-Ming Qi ◽  
Zi-Qiang Zhu
Keyword(s):  
Carbon Dioxide ◽  
Elevated Pressure

scholarly journals A Method for the Measurement of Carbon Dioxide Desorption from Coal in the Elevated Pressure Range

1996 ◽  
Vol 13 (2) ◽  
pp. 71-84 ◽  
Author(s):  
Adam Nodzeński
Keyword(s):  
Carbon Dioxide ◽  
Heat Exchange ◽  
Pressure Range ◽  
Elevated Pressure ◽  
Gas Pressure ◽  
Coal Bed ◽  
Empirical Equations ◽  
Grain Sizes ◽  
Gas Desorption ◽  
Endothermic Process

During the liberation of gas from a coal bed, the temperature of the system is decreased because desorption is an endothermic process and heat exchange with the surroundings is difficult. A method for measuring gas desorption in the elevated pressure range, enabling investigations under isothermal and quasi-adiabatic conditions, was described. The results of carbon dioxide desorption from Polish coal were presented. The study was carried out using different rates of decrease in the external gas pressure for different coal grain sizes. The non-isothermal desorption curves thus obtained were described using empirical equations. Extrapolation of the equation constants obtained enabled the desorption curves to be calculated for the limit of decrease in rate of the external gas pressure and of grain size. It was found experimentally that the dependence of the decrease in coal temperature on the amount of desorbed gas is linear provided that heat exchange with the surroundings is limited.

Carbon dioxide sorption on polish ortholignite coal in low and elevated pressure

2013 ◽  
Vol 3-4 ◽  
pp. 44-48 ◽  
Author(s):  
Paweł Baran ◽  
Janusz Cygankiewicz ◽  
Katarzyna Zarębska
Keyword(s):  
Carbon Dioxide ◽  
Elevated Pressure ◽  
Carbon Dioxide Sorption

scholarly journals Selected combustion parameters of biogas at elevated pressure–temperature conditions

2012 ◽  
Vol 148 (1) ◽  
pp. 40-47
Author(s):  
Stanisław SZWAJA ◽  
Wojciech TUTAK ◽  
Karol GRAB-ROGALIŃSKI ◽  
Arkadiusz JAMROZIK ◽  
Arkadiusz KOCISZEWSKI
Keyword(s):  
Carbon Dioxide ◽  
Ignition Delay ◽  
Combustion Temperature ◽  
Laminar Flame ◽  
Engine Performance ◽  
Elevated Pressure ◽  
Flame Speed ◽  
Methane Content ◽  
Laminar Flame Speed ◽  
Adiabatic Combustion Temperature

Results from tests conducted in several RTD centers lead to conclusion that biogas as a potential fuel for the internal combustion (IC) spark ignited (SI) engine features with its satisfactory combustion predisposition causing smooth engine run without accidental misfiring or knock events. This good predisposition is obtained due to carbon dioxide (CO2) content in the biogas. On the other hand, carbon dioxide as incombustible gas contribute to decrease in the brake power of the biogas fueled engine. To analyze mutual CO2 and CH4 content on biogas burning the combustion parameters as follows: adiabatic combustion temperature, laminar flame speed and ignition delay of biogas with various methane content were determined and presented in the paper. Additionally, these parameters for pure methane were also included in order to make comparison between each other. As computed, ignition delay, which has is strongly correlated with knock resistance, can change several times with temperature increase, but does not change remarkably with increase in methane content. Adiabatic combustion temperature does not also ought to influence on engine performance or increase in engine cooling and exhaust losses due to its insignificant changes. The largest change was observed in laminar flame speed, that can influence on development of the first premixed combustion phase.

scholarly journals Rheology in the Presence of Carbon Dioxide (CO2) to Study the Melt Behavior of Chemically Modified Polylactide (PLA)

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1108
Author(s):  
Dominik Dörr ◽  
Tobias Standau ◽  
Svenja Murillo Castellón ◽  
Christian Bonten ◽  
Volker Altstädt
Keyword(s):  
Carbon Dioxide ◽  
Molecular Weight ◽  
Reactive Extrusion ◽  
Elevated Pressure ◽  
Organic Peroxide ◽  
Recrystallization Temperature ◽  
Chemical Modifier ◽  
Rheological Measurements ◽  
Blowing Agent ◽  
Carbon Dioxide Co2

For the preparation of polylactide (PLA)-based foams, it is commonly necessary to increase the melt strength of the polymer. Additives such as chain extenders (CE) or peroxides are often used to build up the molecular weight by branching or even crosslinking during reactive extrusion. Furthermore, a blowing agent with a low molecular weight, such as carbon dioxide (CO2), is introduced in the foaming process, which might affect the reactivity during extrusion. Offline rheological tests can help to measure and better understand the kinetics of the reaction, especially the reaction between the polymer and the chemical modifier. However, rheological measurements are mostly done in an inert nitrogen atmosphere without an equivalent gas loading of the polymer melt, like during the corresponding reactive extrusion process. Therefore, the influence of the blowing agent itself is not considered within these standard rheological measurements. Thus, in this study, a rheometer equipped with a pressure cell is used to conduct rheological measurements of neat and chemical-modified polymers in the presence of CO2 at pressures up to 40 bar. The specific effects of CO2 at elevated pressure on the reactivity between the polymer and the chemical modifiers (an organic peroxide and as second choice, an epoxy-based CE) were investigated and compared. It could be shown in the rheological experiments that the reactivity of the chain extender is reduced in the presence of CO2, while the peroxide is less affected. Finally, it was possible to detect the recrystallization temperature Trc of the unmodified and unbranched sample by the torque maximum in the rheometer, representing the tear off of the stamp from the sample. Trc was about 13 K lower in the CO2-loaded sample. Furthermore, it was possible to detect the influences of branching and gas loading simultaneously. Here the influence of the branching on Trc was much higher in comparison to a gas loading.

Gas composition of pressurized, perfused gas pockets and the fish swim bladder

1962 ◽  
Vol 17 (2) ◽  
pp. 275-282 ◽  
Author(s):  
J. Piiper ◽  
H. T. Humphrey ◽  
H. Rahn
Keyword(s):  
Carbon Dioxide ◽  
Elevated Pressure ◽  
Swim Bladder ◽  
Gas Composition ◽  
Absorption Process ◽  
Differential Absorption ◽  
Partial Pressures

The behavior of the composition of pressurized, perfused gas pockets is analyzed in theory and experimentally, with the aim of contributing to the understanding of the effect of differential absorption on the composition of the fish swim bladder gas. The equations describing the change in the composition of pressurized, perfused gas pockets are derived and experimentally verified. If a gas pocket initially containing room air is subjected to elevated pressure and perfused with water equilibrated with room air, the concentration of the less soluble gas nitrogen increases during the absorption process. High partial pressures of nitrogen and argon found in swim bladders of fish living at great depths can be qualitatively explained on the basis of accumulation of these gases by preferential absorption of oxygen and carbon dioxide, in connection with certain assumptions on the mode of secretion of the gases Submitted on October 9, 1961

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