Infrared studies of carbon monoxide and carbon dioxide adsorption on platinum/ceria: the characterization of active sites

1988 ◽  
Vol 92 (13) ◽  
pp. 3891-3899 ◽  
Author(s):  
D. W. Daniel
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Active Sites ◽  
Carbon Dioxide Adsorption ◽  
Infrared Studies

Reactions of carbon with atomic gases

1959 ◽  
Vol 12 (4) ◽  
pp. 533 ◽  
Author(s):  
JD Blackwood ◽  
FK McTaggart
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Water Vapour ◽  
Active Sites ◽  
Atmospheric Temperature ◽  
Carbon Surface ◽  
Hydrogen Atoms ◽  
Different Temperatures ◽  
Atomic Species ◽  
Oxygen Groups

Wood chars were reacted at atmospheric temperature with hydrogen atoms, oxygen atoms and carbon monoxide, hydrogen atoms and hydroxyl radicals, produced by the action of a radio frequency field on hydrogen, carbon dioxide, and water vapour respectively. The chars were prepared at different temperatures and contained different amounts of oxygen. The experimental results showed that the gases must be present in the atomic form before reaction with the carbon can take place and that such species react on the carbon-surface independently of active sites. In normal gasification processes the atomic species appear to be produced at active centres, which for the chars used could be correlated with specific oxygen groups remaining in the carbon. It is suggested that these groupings may have a pyran structure. An explanation has been put forward for the retardation of the carbon-water vapour reaction by hydrogen, and of the carbon-carbon dioxide reaction by carbon monoxide. These are considered as due to reverse mechanisms which decrease the concentration of the atomic species and not to the blocking of active sites by adsorption of the retardant.

Characterization of Methane Number for Producer Gas Blends

2013 ◽  
Author(s):  
Daniel M. Wise ◽  
Daniel B. Olsen ◽  
Myoungjin Kim
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Natural Gas ◽  
Producer Gas ◽  
Combustion Pressure ◽  
Natural Gas Engines ◽  
Gaseous Fuels ◽  
Combustion Properties ◽  
Methane Number

Producer gas, any of a variety of gases generated from biomass gasification, is a renewable gaseous fuel that can be burned in gas engines for power production. Producer gas consists primarily of methane, hydrogen, carbon monoxide, carbon dioxide, and nitrogen. These gas blends can be problematic as a fuel for natural gas engines due to widely varying composition and significantly different fuel properties than natural gas. Characterization of combustion properties of different producer gas compositions is critical if the gas engine is to be operated reliably and at the greatest efficiency possible. A sample space of 35 producer gas blends consisting of distinct percentages of combustible gases (methane, hydrogen, and carbon monoxide) and diluent (carbon dioxide and nitrogen) is created to provide a basis for methane number testing. A test cell is established to mix producer gas blends of desired constituent makeup for consumption in a Waukesha F2 Cooperative Fuel Research (CFR) engine to directly measure methane number for each blend. Additional measurements include combustion pressure statistics, fuel consumption, and power output. Methane number is correlated to combustion pressure statistics and producer gas properties. Methane number measurements are compared with predictions using the software AVL Methane, often employed by engine manufacturers to characterize gaseous fuels. Measured methane number shows a strong correlation to 0–10% and 10–90% burn durations. The predicted methane number values from AVL Methane are significantly different than measured methane number in many cases. The error in the prediction is strongly dependent on the amount of carbon monoxide and hydrogen in the producer gas.

Observation of catalytic Cu in methanol synthesis catalysts by atomic-resolution TEM

1990 ◽  
Vol 48 (4) ◽  
pp. 284-285
Author(s):  
P.S. Schabes-Retchkiman ◽  
L. Rendon
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Active Sites ◽  
Atomic Resolution ◽  
Valence States ◽  
Synthesis Catalysts ◽  
Synthesis Of Methanol ◽  
Hydrogenation Of Carbon Monoxide ◽  
Methanol Synthesis Catalysts

Much effort has been done for the characterization of catalysts in which CuO is found together with ZnO and ZnO/alumina, since these combinations constitute catalysts for the synthesis of methanol by the hydrogenation of carbon monoxide. Active catalysts are obtained after reduction in hydrogen at pressures between 50-100 atm and 225° to 275° C. The activity of the catalyst is largely due to the strong interaction between the CuO and ZnO phases. It is clear however that it is copper in various valence states, that is responsible for the catalytic activity, with the ZnO probably acting as both a structural and chemical promoter. However there is still controversy regarding the active sites for catalysis. Several hypotesis have been put forward: 1) The reaction occurs at isolated Cu(I) cations dissolved in the ZnO lattice. 2) The reaction occurs primarily on the metallic Cu component of the catalysts.

Infrared study of carbon monoxide, oxygen, and carbon dioxide adsorption on chromia-silica. I. Carbon monoxide

1969 ◽  
Vol 73 (5) ◽  
pp. 1286-1291 ◽  
Author(s):  
Enzo Borello ◽  
Adriano Zecchina ◽  
Claudio Morterra ◽  
Giovanna Ghiotti
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Carbon Dioxide Adsorption ◽  
Infrared Study

The Reaction of Carbon with Carbon Dioxide at High Pressure

1960 ◽  
Vol 13 (2) ◽  
pp. 194 ◽  
Author(s):  
JD Blackwood ◽  
AJ Ingeme
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Active Sites ◽  
High Pressures ◽  
Carbon Dioxide Molecule ◽  
Partial Pressures ◽  
Different Temperatures ◽  
Adsorbed Carbon ◽  
Forward Process ◽  
High Carbon Dioxide

A study has been made of the reactions of purified carbon with carbon dioxide at pressures up to 40 atm and in the temperature range 790-870 �C. The effect of carbon monoxide has been examined by adding varying proportions of this gas to the carbon dioxide supplied to the reactor bed. At high carbon dioxide and carbon monoxide partial pressures, the rate of formation of carbon monoxide is greater than would be expected from the mechanism proposed by Gadsby et al. (1948). A mechanism has been proposed whereby the increased rate may be explained by additional steps involving the interaction of a carbon dioxide molecule with an adsorbed carbon monoxide to produce adsorbed oxygen, thus : ������������������ CO2 + (CO) → 2CO +(O) A general rate equation has been derived which includes this step and satisfies the experimental results. The reverse mechanism by which carbon monoxide can disappear is not the simple reverse of the forward process and at high pressures equilibrium cannot be expressed by the usual expression derived for the simple single-stage reversible process. The possible nature of active sites has been examined by studying the reactivity of a series of chars prepared at different temperatures. The reactivity appears to be related to the oxygen content of the chars and the type of active centres involved may be different from those which control the carbon-steam mechanism.

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