Showing papers in "Industrial & Engineering Chemistry Product Research and Development in 1983"

Effects of reactor severity on the gas-phase pyrolysis of cellulose- and kraft lignin-derived volatile matter

Abstract: Yields of permanent gases evolved by the gas-phase pyrolysis of cellulose- and lignin-derived voltatile matter cannot be correlated with a commonly used kinetic severity function. Instead, engineers explained the dependence of gas yields on temperature and residence time by a global mechanism composed of two competing reactions. The first creates permanent gases by cracking the volatile matter, whereas the second creates refractory condensable materials. For cellulose, the cracking reaction has an apparent activation energy of 49 kcal/g-mol, and the competing reaction 15 kcal/g-mol. The gas-phase cracking of cellulosic volatile matter involves competition between the dehydration (resulting in methane and ethylene formation) and decarboxylation reactions; the fraction of carbon atoms dedicated to carbon monoxide formation by the cracking reaction is not influenced by temperature. For lignin, competition exists between ethylene and carbon dioxide formation; the fraction of carbon atoms dedicated to carbon monoxide and methane formation is not influenced by temperature.

Biomass pretreatment with water and high-pressure oxygen. The wet-oxidation process

Abstract: A biomass pretreatment process called wet oxidation that utilized water, oxygen (240-480 psi), and temperatures above 120 degrees C was applied to loblolly pine, black oak, and a mixture of low-grade hardwoods. The process was found to be effective for fractionating the hemicellulose, lignin, and cellulose components of wood. Acid hydrolysis studies showed that the wet oxidation also enhanced the rate at which cellulose was hydrolyzed by acids to glucose. (Refs. 28).

Catalytic cracking with an interlayered clay. A two-dimensional molecular sieve

Abstract: L'alternance de bentonite commerciale avec des cations hydroxy aluminium (Al 13 O 4 (OH) 24 (H 2 O) 12 ) 7+ produit une argile expanse avec une surface, une distribution de pores plus typique des zeolites que des argiles

Aqueous catalyst systems for the water-gas shift reaction. 1. Comparative catalyst studies

Abstract: A comparative study of both aqueous and nonaqueous catalysts - metal carbonates, alkali metal salts, and supported metal oxides - for the water-gas shift reacton utilized a pressurized aqueous batch reactor system. Test results showed that (1) alkali metal salts catalyze the water-gas shift reaction in the temperature range of 390/sup 0/-750/sup 0/F, (2) alkali metal salts and some transition metal salts are significantly more active than similar alkali earth compounds, (3) several alkali compounds can act as catalysts (or generate a catalytic species in situ) for the water-gas shift reaction in a pressurized aqueous system, (4) the cation need not be a metal, and (5) aqueous solutions of sodium carbonate may display activity levels similar to or higher than those of supported metal oxides in a pressurized system.

Steam explosion of mixed hardwood chips as a biomass pretreatment

Abstract: Mixed southern hardwood chips were pretreated by steam explosion. Reaction temperatures ranged from 167 to 235 degrees C, with reaction times of 0.5, 1.0, and 2.0 min. The highest reaction temperatures degraded up to two-thirds of the hemicelluloses, with the remainder soluble in hot water. The cellulose content decreased only slightly at the higher reaction temperatures. The steam-explosion pretreatment did not increase the rate of acid hydrolysis of the cellulose. The apparent lignin content increased as teh steam-explosion temperature increased. The lignin was partially extractable by a hot alkaline solution. No differences were observed with the addition of NaOH catalyst. Scanning electron microscopy showed that wood chips exploded under mild conditions were only partially defibrated, while severe conditions shredded the fibers into many individual fragments. (Refs. 26).

Aqueous catalyst systems for the water-gas shift reaction. 2. Mechanism of basic catalysis

Abstract: A proposed mechanism for the catalysis of the water-gas shift reaction by basic aqueous solutions in a pressurized reactor is a cyclic system with three intermediate anions: carbonate, hydroxide, and formate. A carbonate ion reacts with water to form hydroxide and carbon dioxide; the hydroxide ion reacts with carbon monoxide to generate formate that decomposes to carbonate and formaldehyde and, in turn, hydrogen. The mechanism can proceed in the presence of any basic catalyst precursor that generates one of the three catalytic species.

Conversion of biomass into chemicals with high-temperature wet oxidation

Abstract: Etude experimentale de l'influence de la pression d'oxygene, de la temperature, du type de bois et de l'addition de sulfate ferrique sur le rendement en acides organiques lors de l'oxydation de bois humide a haute temperature (127-277°C)

Storage stability of synfuels from oil shale. 1. General features of sediment formation in model fuel systems

Abstract: On etudie la formation de sediments dans les distillats moyens. L'effet de composes azotes sur la formation de sediments a ete determinee en utilisant des composes azotes purs

Hydroisomerization and hydrocracking. 5. Kinetic analysis of rate data for n-octane

Abstract: Etude cinetique des reactions d'hydrocraquage et d'hydroisomerisation du n-octane dans un reacteur du type Berty en presence d'un catalyseur zeolite Y contenant 0,5% en poids de Pt et dans les intervalles de t 180-240°C et de p 5-100 bars

Biomass refining: protein and ethanol from alfalfa.

Abstract: Presentation, sur l'exemple de la luzerne, de differentes methodes de production simultanee de proteines et de combustibles et d'autres produits chimiques a partir de la biomasse. Liste de regions des Etats-Unis ou la production de proteines et d'ethanol a partir de luzerne parait possible

Storage stability of synfuels from oil shale. II: Effects of nitrogen compound type and the influence of other nonhydrocarbons on sediment formation in model fuel systems

Abstract: L'activite de composants varies depend grandement de leur structure. Les heterocycles non basiques azotes avec des groupes alkyls avec des cycles de carbone adjacents a l'azote sont particulierement reactifs. Par contraste d'autres composes azotes ne sont pas reactifs meme apres un stockage excedent 100 jours a 43,3°C

Effect of composition and pretreatments on the activity of copper-chromium-based catalysts for the oxidation of carbon monoxide

Abstract: Presentation des resultats d'une etude experimentale realisee sur des catalyseurs sur ou sans support preparees a partir de solutions de nitrates de fer et de chrome

Thermal oxidative degradation reactions of linear perfluoroalkyl ethers

Abstract: The mechanisms operative in thermal oxidative degradation of Fomblin Z and hexafluoropropene oxide derived fluids and the effect of alloys and additives upon these processes are investigated. The nature of arrangements responsible for the inherent thermal oxidative instability of the Fomblin Z fluids is not established. It was determined that this behavior is not associated with hydrogen end groups or peroxy linkages. The degradation rate of these fluids at elevated temperatures in oxidizing atmospheres is dependent on the surface/volume ratio. Once a limiting ratio is reached, a steady rate appears to be attained. Based on elemental analysis and oxygen consumption data, CF2OCF2CF2O2, no. CF2CF2O, is one of the major arrangements present. The action of the M-50 and Ti(4 Al, 4 Mn) alloys is much more drastic in the case of Fomblin Z fluids than that observed for the hexafluoropropene derived materials. The effectiveness of antioxidation anticorrosion additives, P-3 and phospha-s-triazine, in the presence of metal alloys is very limited at 316 C; at 288 C the additives arrested almost completely the fluid degradation. The phospha-s-triazine appears to be at least twice as effective as the P-3 compound; it also protected the coupon better. The Ti(4 Al, 4 Mn) alloy degraded the fluid mainly by chain scission processes this takes place to a much lesser degree with M-50.

Kinetics of the hydrogenation of carbon dioxide over supported nickel

Abstract: The kinetics of the hydrogenation of carbon dioxide to methane was studied using a 58% nickel catalyst supported on kieselguhr. The volume percentages of carbon dioxide and hydrogen in feed mixtures were varied from 20 to 30% and 67 to 80%, respectively, covering a total pressure range of 100-250 psig and temperatures of 530/sup 0/-560/sup 0/F. Subsequently, a simple power rate model correlated the experimental data.

Hydroisomerization and hydrocracking. 4. Product distribution from n-octane and 2,2,4-trimethylpentane

Abstract: Etude experimentale de la distribution des produits des reactions du titre realisees dans un reacteur du type Berty en presence d'un catalyseur zeolite Y contenant 0,5% en poids de Pt et dans les intervalles de t 80-240°C, et de p 5-100 bars

Norbornadiene-quadricyclane system in the photochemical conversion and storage of solar energy

Abstract: Presentation de donnees experimentales sur la conversion photochimique du norbornadiene en quadricyclane. Evaluation, a l'aide de ces donnees et de donnees sur le rayonnement solaire, d'un collecteur photochimique plan discontinu. Analyse economique previsionnelle de ce systeme de conversion et stockage de l'energie solaire

Dynamic behavior of automotive catalysts. 2. Carbon monoxide conversion under transient air fuel ratio conditions

Abstract: Presentation de resultats de mesure des emissions de CO au cours d'une serie de cycles d'essais realises pour differentes valeurs du rapport air/combustible, avec des catalyseurs Pt/Pd/Rh/Al 2 O 3 contenant ou non du cerium a l'etat libre

Trace metals in crude oils from Saudi Arabia

Abstract: Presentation et discussion de resultats d'analyse de 17 metaux a l'etat de trace dans neuf petroles bruts d'Arabie Saoudite, a partir desquels on determine les rapports V/Ni, V/Fe, V/Mg, V/Cu, V/Cr et V/Zn

The alkaline electrolytic process for zinc production: a critical evaluation

Abstract: The alkaline leach and electrolysis process for zinc production is compared to the conventional acid sulfate process in terms of both energy saving and technical merit In addition, the potential for industrial application of the alkaline process is discussed on the basis of present market conditions, possible future zinc market scenarios, and the probability of increased secondary zinc recovery 37 references, 4 figures, 3 tables

Use of byproduct lignins as extenders in asphalt

Abstract: Etude experimentale de l'influence de l'addition de 10 a 50% de lignine, sous-produit de la production d'ethanol a partir de la biomasse sur les proprietes des asphaltes et des revetements utilisant ces melanges comme liants