Showing papers on "Partial oxidation published in 1994"
TL;DR: In this article, the surface vanadium oxide phase on all the oxide supports is essentially independent of the loading below monolayer coverage, which suggests that a structural difference is not responsible for the difference in reactivity of the various supported vanadium dioxide catalysts.
499 citations
TL;DR: In this paper, a review of the application of biand multi-metallic catalysts in the aqueous phase oxidation of alcohols with molecular oxygen is presented, focusing on the transformation of primary alcohols to aldehydes or carboxylic acids.
425 citations
TL;DR: In this article, the partial oxidation of CH4 in O2 near atmospheric pressure to produce syngas was investigated on monolith-supported catalysts in an autothermal flow reactor at residence times of ∼10 msec.
297 citations
Patent•
22 Dec 1994TL;DR: In this paper, a process for the catalytic partial oxidation of a hydrocarbon feedstock comprises contacting a feed comprising a hydrocarine feedstock and an oxygen-containing gas with a catalyst at an elevated temperature under conditions such that the catalyst will be susceptible to a thermal shock.
Abstract: A process for the catalytic partial oxidation of a hydrocarbon feedstock comprises contacting a feed comprising a hydrocarbon feedstock and an oxygen-containing gas with a catalyst at an elevated temperature under conditions such that the catalyst will be susceptible to a thermal shock, the catalyst having the form of a porous monolithic structure and comprising a catalytically active metal supported on a zirconia-based carrier.
160 citations
Abstract: The reaction of methane with surface oxygen as well as the interaction of methane/oxygen mixtures with a Rh(1 wt%)/γ-Al2O3 catalyst was studied by applying the temporal-analysisof-product (TAP) reactor. The product distribution was strongly affected by the degree of surface reduction. CO2 is formed as a primary product via a redox mechanism with the participation of surface oxygen. The dehydrogenation of methane yielding carbon deposits on the surface occurs on reduced surface sites. The formation of CO proceeds with high selectivity (up to 96%)at 1013 K via fast reaction of surface carbon species with CO2.
157 citations
TL;DR: In this article, the mechanism of reaction and surface structures for the adsorption and partial oxidation of methanol on the oxygen precovered Cu(110) surface have been studied with a variety of surface sensitive techniques.
152 citations
Journal Article•
TL;DR: Autothermal Reforming (ATR) as mentioned in this paper is a low-investment process using a simple reactor design, which is soot-free due to burner design and fixed-bed catalyst.
Abstract: Synthesis gas or syngas, i.e., mixtures of CO and H[sub 2], is a major route from hydrocarbons to many important bulk chemicals ranging from acetic acid to ammonia. Syngas conversion uses hydrocarbon feedstocks, steam, O[sub 2] and CO[sub 2], either separately or in combinations. Autothermal reforming (ATR) is a low-investment process using a simple reactor design. The process is soot-free due to burner design and fixed-bed catalyst. Developed in the late '50s, ATR's main application was for ammonia and methanol syntheses. In ammonia plants, hydrogen production was maximized by operating at high H[sub 2]O/C ratios ranging from 2.5 to 3.5 mole/mole. In methanol units, CO[sub 2] recycle adjusted the syngas composition. ATR is also used to co-produce CO and H[sub 2] as separate streams at H[sub 2]O/C ratios of 1.4 to 2.0 mole/mole. recent developments and optimizations allow cost-effective operation at very low H[sub 2]O/C feed ratios to produce CO-rich syngas. The paper describes the process, including feedstocks and reactor design, the chemical reactions, development and improvements to the process, test results, soot formation, burner design, burner testing, applications, thermodynamic calculations, industrial application, noncatalytic and catalytic partial oxidation, and future uses.
118 citations
TL;DR: In this article, the best system, La-Rh-O, gave 95% conversion with 98% selectivity to carbon monoxide even after 120 h on stream at 800°C.
Abstract: Catalytic partial oxidation of methane to synthesis gas was performed over La-M-O, with M = Co, Cr, Ni, Rh. The best system, La-Rh-O, gave 95% conversion with 98% selectivity to carbon monoxide even after 120 h on stream at 800°C. La-Ni-O deactivated after about 17 h on stream, probably due to coke formation. La-(Ni,Rh)-O showed improved stability compared to La-Ni-O. La-Co-O gave mainly carbon dioxide during the first 30 h of the test. Then the activity changed to give mainly carbon monoxide. Some deactivation was observed during the next 50 h test. La-Cr-O produced mainly carbon dioxide. In order to stabilize the small metal clusters formed on the catalyst surface, a second metal will probably have to be included in the perovskite structure.
112 citations
TL;DR: In this paper, the production of synthesis gas (CO + H 2 ) by the catalytic partial oxidation of CH 4 in air or O 2 in static fluidized beds at atmospheric pressure has been examined over Pt, Rh, and Ni catalysts coated on 100-μm α-Al 2 O 3 beads.
108 citations
TL;DR: In this article, reaction steps in the oxidation of CH4 to CO and H2 over a Rh(1 wt%)/γ-Al2O3 catalyst were studied using in situ DRIFTS at 973 K and 0.1 MPa.
Abstract: Reaction steps in the oxidation of CH4 to CO and H2 over a Rh(1 wt%)/γ-Al2O3 catalyst were studied using in situ DRIFTS at 973 K and 0.1 MPa. Product distribution and the resulting absorption band intensities of the respective adsorbates were strongly influenced by oxygen coverage and carbon deposits on the surface. CH4 is dehydrogenated to carbon deposits and H2 and is simultaneously oxidized to CO2 and H2O. OH surface groups in the support are involved in the CHx conversion to CO via reforming reaction. The reaction of surface carbon with CO2 was assumed to contribute to CO formation. Formate is a by-product of the reaction.
100 citations
TL;DR: The interaction of silver foil with oxygen over a wide range of temperatures and O2 pressures has been studied by XPS, TPD, and TPR as discussed by the authors, and it has been shown that depending on the treatment conditions two adsorbed oxygen states with a different ionicity of the AgO bond can be formed, as well as oxygen dissolved in the silver bulk.
TL;DR: In this article, the production of olefins and synthesis gas (CO and H2) from CH4, C2H6 C3H8, and n-C4H10 in the presence of air or O2 at atmospheric pressure has been examined over monoliths coated with various metals at residence times between 10−3 and 10−2 s.
TL;DR: In this article, at least three distinct linearly bound carbonyl species are identified in the adsorption of CO2 or CO2 + H2 over Ru RuO x TiO 2 catalyst.
TL;DR: In this article, the experimental characterization of two partial oxidation reactions, the partial oxidation of methane to synthesis gas (> 90% selectivities at > 90% conversion) and the oxidative dehydrogenation of higher alkanes to olefins (70% selectivity at > 80% conversion), was described.
TL;DR: In this article, the authors describe experiments in which monolith catalysts are used for partial oxidation of CH4 and C2H6 to produce synthesis gas or alkenes by direct oxidation at or above atmospheric pressure in pure O2 in nearly adiabatic reactors operating at 1000°C with very high flow rates.
TL;DR: The modification of clean silver foil by C2H4 + O2 and CO+O2 reaction mixtures has been studied by XPS, TPD, and TPR as discussed by the authors.
TL;DR: In this paper, the partial oxidation of methane to formaldehyde with molecular O2 has been investigated on various commercial bare SiO2 samples and silica-supported MoO3 and V2O5 catalysts at 550-650°C in batch, pulse, and continuous flow reactors at 1.7 bar.
TL;DR: In this paper, a new plasma reactor based on gliding discharges (GlidArc) at atmospheric pressure with a high efficiency is presented. But it is not shown how to obtain CO + H 2 synthesis gas from CH 4 + CO 2 mixtures.
TL;DR: In this article, the homogeneous gas phase partial oxidation of methane to oxygenates in the temperature range 300-500 C and at pressures of 3-6 MPa was investigated and the best methanol yield achieved in this study was 1.8 mol%.
Abstract: Direct conversion of natural gas to liquid products has been under investigation for most of this century, but no commercial processes are practiced to date. The partial oxidation of methane to methanol would be a particularly attractive option of natural gas upgrading, provided yields in excess of 10% can be achieved. A large number of studies have been published on the subject over the past 70 years, but yields are in general low and more promising results difficult to reproduce. This work focused on the homogenous gas phase partial oxidation of methane to oxygenates in the temperature range 300--500 C and at pressures of 3--6 MPa and compared the experimental results with model calculations. The most important parameters controlling selectivities and yields were identified as the temperature in the reaction zone and the reactor geometry. The best methanol yield achieved in this study was 1.8 mol%. Innovative reactor design may result in significantly higher methanol yields than have been achieved to date.
Patent•
02 Jun 1994TL;DR: In this paper, the process produces a stream of hot clean gas substantially free from particulate matter, alkali metal compounds, hydrogen halides, hydrogen cyanide, sulfur-containing gases, and with or without ammonia for use as synthesis gas, reducing gas, or fuel gas.
Abstract: The process produces a stream of hot clean gas substantially free from particulate matter, alkali metal compounds, hydrogen halides, hydrogen cyanide, sulfur-containing gases, and with or without ammonia for use as synthesis gas, reducing gas, or fuel gas. A pumpable fuel selected from liquid hydrocarbonaceous fuel or liquid emulsions thereof, an aqueous slurry of petroleum coke, and mixtures thereof and containing halides, alkali metal compounds, sulfur, nitrogen and inorganic ash, it reacted by partial oxidation to produce a hot raw gas stream comprising H₂, CO, CO₂, H₂O, CH₄, NH₃, HCN, HC1, HF, H₂S, COS, N₂, Ar, particulate matter, vapor phase alkali metal compounds, and molten slag. The hot raw gas stream is cooled and cleaned. Optionally, ammonia is removed by being catalytically disproportionated into N₂ and H₂. The process gas stream is cooled and halides and HCN in the gas stream are reacted with a supplementary alkali metal compound to remove HC1, HF and HCN. Alkali metal halides and alkali metal cyanide, vaporized alkali metal compounds and residual fine particulate matter are removed by further cooling and filtering. The sulfur-containing gases in the process gas stream are then reacted at high temperature with a mixed metal oxide sulfur sorbent material to produce a sulfided sorbent material which is then separated from the hot clean purified gas stream having a temperature of at least 540°C.
TL;DR: In this paper, a non-group VIII metal catalyst, rhenium supported on γ-alumina has been tested as a catalyst for the partial oxidation and dry reforming of methane at different temperatures.
TL;DR: In this article, the authors describe their efforts to understand the reaction pathways leading to the formation of partial oxidation products, which can greatly limit the utility of catalytic oxidation for VOC destruction.
Abstract: The control of airborne emissions of volatile organic compounds (VOCs) can often be achieved through catalytic oxidation over noble metals (e.g., platinum) supported on alumina. For many classes of materials, high levels of conversion to innocuous materials (CO[sub 2] and water) can be obtained at low temperature, without the appearance of any reaction intermediates. However, other classes of compounds, such as oxygenated species, do produce significant quantities of partial oxidation products, which can greatly limit the utility of catalytic oxidation for VOC destruction. Within this paper, the authors describe their efforts to understand the reaction pathways leading to the formation of partial oxidation products. Oxidation of ethyl acetate over a platinum catalyst dispersed on [gamma]-alumina and supported on a cordierite monolith has been found to produce partial oxidation products including ethanol, acetic acid, and diethyl ether. The reaction pathways leading to the formation of these partial oxidation products have been developed by examining the reaction over the alumina support without any noble metal present. Platinum is seen to produce complete oxidation products, almost exclusively. The total product spectrum can be obtained by assuming no interaction between alumina and platinum; in other words, simple combination of the results observed from reactionmore » over alumina with the complete oxidation pathway catalyzed by platinum.« less
TL;DR: In this paper, the partial oxidation of methane to synthesis gas over supported Rh catalysts is investigated, paying particular attention to removing heat transport limitations and identifying the reaction conditions within the kinetic-controlling regime.
Abstract: The partial oxidation of methane to synthesis gas over supported Rh catalysts is investigated, paying particular attention to removing heat transport limitations and identifying the reaction conditions within the kinetic-controlling regime. The results obtained suggest that the reaction follows the sequence of total oxidation to CO2 and H2O, followed by reforming reactions to synthesis gas.
Patent•
19 Oct 1994TL;DR: In this paper, the authors proposed a method to produce hydrogen-rich gas by the partial oxidation of a saturated gaseous hydrocarbonaceous fuel (8) or a mixture of saturated Gaseous H2O and a liquid H2C in a gas generator.
Abstract: This invention relates to the production of hydrogen-rich gas (92) by the partial oxidation of a saturated gaseous hydrocarbonaceous fuel (8) or a mixture of saturated gaseous hydrocarbonaceous fuel and a liquid hydrocarbonaceous fuel in a gas generator (1). In the process, a saturated gaseous hydrocarbonaceous fuel (8) from a subsequent fuel gas saturator (50) is preheated by indirect heat exchange in heat exchanger (43) with a portion of shifted process gas stream (42) from a catalytic water-gas direct shift conversion zone (38) and reacted in said partial oxidation gas generator (1). The process gas stream from the noncatalytic partial oxidation gas generator (1) is quench cooled and scrubbed with water in gas scrubbing column (24) and preheated by indirect heat exchange in heat exchanger (30) with a second portion of the process gas stream (35) from the shift conversion zone (38) prior to catalytically reacting the CO and H2O in the process gas stream in the shift conversion zone (38) to increase its H2 content. The shifted process gas stream is cooled and dewatered in heat exchanger (53) to produce shift condensate which is used to saturate the aforesaid preheated gaseous hydrocarbonaceous fuel feedstream (8) to the partial oxidation gas generator (1).
Patent•
21 Dec 1994TL;DR: In this article, a process for the preparation of carbon monoxide and/or hydrogen from a hydrocarbon feedstock is described, in which a first stage is subjected to a catalytic partial oxidation process in which it is contacted with an oxygen-containing gas, which gaseous mixture also comprises nitrogen, with a catalyst comprising as a catalytically active metal rhodium, iridium or platinum.
Abstract: The present invention provides a process for the preparation of carbon monoxide and/or hydrogen from a hydrocarbon feedstock. The hydrocarbon feedstock is subjected in a first stage to a catalytic partial oxidation process in which it is contacted, as a gaseous mixture comprising the hydrocarbon feedstock and an oxygen-containing gas, which gaseous mixture also comprises nitrogen, with a catalyst comprising as a catalytically active metal rhodium, iridium or platinum. At least a portion of the products of the first stage is subjected in a second stage to a process in which ammonia and/or hydrogen cyanide is removed.
Patent•
06 Aug 1994
TL;DR: In this article, the level of metal or metals from the Platinum Group, as percent by weight, is defined as the ratio of metal to the total weight of the catalyst and the carrier.
Abstract: Process of catalytic partial oxidation of natural gas in order to obtain synthesis gas and formaldehyde, integrated with processes of hydrogenation of the resulting CO, such as Fischer-Tropsch and methanol syntheses. Such an oxidation is carried out by means of a catalyst constituted by one or more compounds of metals form Platinum Group, which is given the shape of wire meshes, or is deposited on a carrier made from inorganic compounds, in such a way that the level of metal or metals from Platinum Group, as percent by weight, is comprised within the range of from 0.1 to 20% of the total weight of catalyst and carrier, by operating at temperatures comprised within the range of from 300 to 950°C, under pressures comprised within the range of from 0.5 to 50 Atm, at space velocities comprised within the range of from 20,000 to 1,500,000 h⁻¹.
Patent•
20 May 1994
TL;DR: In this article, a process for the removal of HCN from gas mixtures that contain at least HCN and sulfur compounds, especially from gas mixture that are obtained by partial oxidation of hydrocarbons, by catalytic decomposition of HCNs, as well as a catalyst for the decomposition.
Abstract: The invention relates to a process for the removal of HCN from gas mixtures that contain at least HCN and sulfur compounds, especially from gas mixtures that are obtained by partial oxidation of hydrocarbons, by catalytic decomposition of HCN, as well as a catalyst for the decomposition of HCN. According to the invention, the gas mixture is brought into contact with a catalyst which decomposes the HCN by hydrogenation and/or by hydrolysis and COS that is contained in the gas mixture is decomposed at least partially in this catalyst by hydrolysis. Advantageously, a catalyst that is based on titanium oxide and/or zirconium oxide as a vehicle and that contains chromium oxide as an active component is used. Advantageously, the catalyst is reduced during catalyst production or before use with H2 and/or a reducing gas at temperatures above the operating temperature of catalytic decomposition.
TL;DR: In this article, the partial oxidation of methane to synthesis gas has been studied in a monolithic type catalyst containing 5 wt% Ni or 1.5 wt.-% Pt. The experiments were carried out at 600-900°C, 1 bar and with space times in the range of 0.2-0.005 s.
TL;DR: In this paper, a single-crystal sapphire tube was used for partial oxidation of methane to methanol, at 10-70 bar, 5-10 mol % O 2 in the feed, and residence times from 0.8 to 7.8 min.
Abstract: Partial oxidation of methane to methanol was examined using a new type of reactor tube, single-crystal sapphire, at 10-70 bar, 5-10 mol % O 2 in the feed, and residence times from 0.8 to 7.8 min. Both the heated length of the tube and the surface area/volume were kept relatively small in comparison to some past studies. Methanol selectivities of ca. 70% at C 1 /O 2 = 14.3 (C 1 /air = 3) and 55-60% at C 1 /O 2 = 5.7 (C 1 /air = 1.2) were attained at 100% O 2 conversion. At 100% O 2 conversion, reactor residence time and temperature profile (e.g., reactor quench cooling, feed preheating) appeared to have little effect on CH 3 OH selectivities. Longer residence times can increase methane conversion at constant temperature until 100% O 2 conversion is reached
TL;DR: In this article, it was shown that new sites, which are formed from P2O4−7 present in nonstoichiometric apatite, are responsible for the selective formation of carbon monoxide.