Partial Oxidation Of Natural Gas Research Articles

Natural Gas Decarbonization to Reduce CO2 Emission From Combined Cycles—Part I: Partial Oxidation

This paper discusses novel schemes of combined cycle, where natural gas is chemically treated to remove carbon, rather than being directly used as fuel. Carbon conversion to CO2 is achieved before gas turbine combustion. Therefore CO2 can be removed from fuel (rather than from exhausts, thus utilizing less demanding equipment) and made available for long-term storage, to avoid dispersion toward the atmosphere and the consequent contribution to the greenhouse effect. The strategy here proposed to achieve this goal is natural gas partial oxidation. The second part of the paper will address steam/methane reforming. Partial oxidation is an exothermic oxygen-poor combustion devoted to CO and H2 production. The reaction products are introduced in a multiple stage shift reactor converting CO to CO2. Carbon dioxide is removed by means of physical or chemical absorption processes and made available for storage, after compression and liquefaction. The resulting fuel mainly consists of hydrogen and nitrogen, thus gas turbine exhausts are virtually devoid of CO2. The paper discusses the selection of some important parameters necessary to obtain a sufficient level of conversion in the various reactors (temperature and pressure levels, methane-to-air or methane-to-steam ratios) and their impact on the plant integration and on the thermodynamic efficiency. Overall performance (efficiency, power output, and carbon removal rate) is predicted by means of a computational tool developed by the authors. The results show that a net efficiency of 48.5 percent, with a 90 percent CO2 removal, can be obtained by combined cycles based on large heavy duty machines of the present technological status, either by using chemical or physical absorption.

Natural Gas Decarbonization to Reduce CO2 Emission From Combined Cycles—Part II: Steam-Methane Reforming

This paper discusses novel schemes of combined cycle, where natural gas is chemically treated to remove carbon, rather than being directly used as fuel. Carbon conversion to CO2 is achieved before gas turbine combustion. The first part of the paper discussed plant configurations based on natural gas partial oxidation to produce carbon monoxide, converted to carbon dioxide by shift reaction and therefore separated from the fuel gas. The second part will address methane reforming as a starting reaction to achieve the same goal. Plant configuration and performance differs from the previous case because reforming is endothermic and requires high temperature heat and low operating pressure to obtain an elevated carbon conversion. The performance estimation shows that the reformer configuration has a lower efficiency and power output than the systems addressed in Part I. To improve the results, a reheat gas turbine can be used, with different characteristics from commercial machines. The thermodynamic efficiency of the systems of the two papers is compared by an exergetic analysis. The economic performance of natural gas fired power plants including CO2 sequestration is therefore addressed, finding a superiority of the partial oxidation system with chemical absorption. The additional cost of the kWh, due to the ability of CO2 capturing, can be estimated at about 13–14 mill$/kWh.

Catalytic membrane reactors for spontaneous synthesis gas production

Over the last several years our work has focused upon determining the interrelationship between crystallographic and thermodynamic properties of solid state metal oxides and how they relate to achieving simultaneous high ionic and electronic conductivity. This work has led to a new class of oxygen anion and electron conducting brownmillerite derived membrane materials which have been incorporated into catalytic membrane reactors (CMRs) for achieving the spontaneous conversion of natural gas to synthesis gas at practical rates with complete materials stability for extended periods. CMR technology under development at Eltron Research, facilitates the exclusive mediation of oxygen from the atmosphere to a desired reaction site — in this case natural gas partial oxidation to synthesis gas. Because this CMR process is exothermic and eliminates the need for a separate oxygen plant, a significant reduction in synthesis gas production costs may be realized compared to currently available technology. Additionally, NO x emissions are eliminated since the membrane only mediates oxygen and excludes atmospheric nitrogen.

99/01968 Influence of catalyst supports on partial oxidation of natural gas to synthesis gas: Chu, W. et al. Tianranqi Huagong, 1998, 23, (3), 29–33. (In Chinese)

99/01968 Influence of catalyst supports on partial oxidation of natural gas to synthesis gas: Chu, W. et al. Tianranqi Huagong, 1998, 23, (3), 29–33. (In Chinese)

97/03716 Simulation of partial oxidation of natural gas to synthesis gas using ASPEN PLUS

Methane partial oxidation is one way of producing synthesis gas which is the feedstock of Fischer-Tropsch synthesis and methanol synthesis. The high ignition temperature of methane partial oxidation is always a concern to industries and researches, leading to inaccuracies in temperature measurement, reaction model development, and subsequent understanding of reaction mechanisms and the predictive abilities of developed models. A gas-flow reactor system incorporating indirect induction heating was designed and operated for the non-catalytic partial oxidation of CH4. Experiments of methane partial oxidation diluted by nitrogen were conducted and the effects of temperature (1270–1767 K), stoichiometry (CH4/O2 = 1–2), and H2 addition were studied. Thermodynamic and kinetic simulations were also performed in this study and compared to the experimental results. Reduced mechanisms were applied in computational fluid dynamics (CFD) simulations to correct the temperature profiles which were adopted in kinetic modelling. Kinetic simulations of the experimental conditions were conducted using reported mechanisms: GRI-Mech 3.0 and the mechanism developed by Glarborg’s group. In general the simulated gas-phase compositions at the exit of the reactor and trends for each set of experiments were consistent with the experimental data. The Glarborg mechanism was found to be more accurate in the prediction of the selectivity of C2 hydrocarbons (particularly acetylene) as the Glarborg mechanism contains more pathways for the conversion of C2H2 into polycyclic aromatic hydrocarbons (PAHs). The combination of CFD modelling and kinetic modelling offset the deviation of temperature measurement and hence provided a sample for high temperature reaction simulation.

Simulation of partial oxidation of natural gas to synthesis gas using ASPEN PLUS

Conversion of natural gas to liquid fuels is a challenging issue. In SMDS process natural gas is first partially oxidized with pure oxygen to synthesis gas (a mixture of H 2 and CO) which is then converted to high quality liquid transportation fuels by utilizing a modernized version of the Fischer-Tropsch reaction. This paper presents a computer simulation of the first stage of the process, i.e. the synthesis gas production from natural gas. ASPEN PLUS equipped with a combustion databank was used for calculations. Concentrations of over 30 combustion species and radicals expected in the synthesis gas have been calculated at equilibrium and several non-equilibrium conditions. Using a sensitivity analysis tool, the relative feed flow rates and reactor parameters have been varied searching to maximize the CO O 2 yield as well as to minimize the undesired nitrogen compounds in the product stream. The optimum reactor temperature for maximizing the CO mole fraction in the synthesis gas was also calculated.

Simulation of the catalytic partial oxidation of methane to synthesis gas

The modeling and simulation of reactors for the catalytic partial oxidation of natural gas to synthesis gas is complex and requires detailed kinetics if it is to be representative and reliable. Adiabatic fixed bed reactors with a catalytic combustion zone fed with methane/oxygen or methane/air mixtures were simulated based upon the kinetics of total combustion, steam reforming and water-gas shift on a Ni catalyst. The steam reforming reactions and water-gas shift reaction are parallel or more or less consecutive to the total combustion, depending upon the degree of reduction of the catalyst, which is determined by the temperature and the gas phase composition. The calculation of the net rates of coke formation was included in the simulation. The influence of carbon dioxide and steam was also investigated.

Modern State of Direct High Pressure Partial Oxidation of Natural Gas to Methanol

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTModern State of Direct High Pressure Partial Oxidation of Natural Gas to MethanolVladimir S. Arutyunov, Valentin Ya. Basevich, and Vladimir I. VedeneevCite this: Ind. Eng. Chem. Res. 1995, 34, 12, 4238–4243Publication Date (Print):December 1, 1995Publication History Published online1 May 2002Published inissue 1 December 1995https://doi.org/10.1021/ie00039a013RIGHTS & PERMISSIONSArticle Views164Altmetric-Citations18LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (754 KB) Get e-Alerts Get e-Alerts

95/05830 From natural gas to liquid hydrocarbons. Part 3. Kinetics of the Fischer-Tropsch synthesis using a nitrogen-rich synthesis gas

For countries in remote areas with large reserves of natural gas, e.g. the State of Qatar, the economic utilization of this gas is in our opinion only possible in a low-cost process that converts the natural gas to liquid hydrocarbons. The basic concept of low-cost process was presented in the first of a series of four papers: in a first step a nitrogen-rich synthesis gas is produced by catalytic partial oxidation of natural gas with air (for details see the second paper). The syngas is then converted by Fischer-Tropsch-synthesis to higher hydrocarbons. In the following and third paper the results of kinetic studies on Fischer-Tropsch-synthesis are discussed. The experiments were carried out by using an alkalized precipitated iron catalyst in a bench-scale reactor at pressures up to 30 bar and temperatures ranging from 200-300°C

Catalytic partial oxidation of natural gas to syngas

We trace the development of catalytic partial oxidation technology for the conversion of natural gas to synthesis gas (CO + H 2) from steam reforming to autothermal reforming to direct oxidation. Synthesis gas which has applications in methanol, ammonia and Fischer-Tropsch synthesis has been conventionally produced by endothermic steam reforming processes in fired tube furnaces. Catalytic partial oxidation is much faster, highly selective in a single reactor, and much more energy efficient. It could thus significantly decrease capital and operating costs of syngas production. In this review, we consider catalysts as well as reactors. Processes, issues and practical difficulties are discussed with academic and industrial efforts presented in parallel. New millisecond contact time direct oxidation processes which eliminate the use of steam and use autothermal reactors orders of magnitude smaller than those used for conventional steam reforming hold promise for commercialization.

Partial oxidation of natural gas to synthesis gas over ruthenium perovskite oxides

New perovskite-related oxides of Ru V have been prepared and evaluated as catalysts for the partial oxidation of natural gas to synthesis gas. Their activity has been compared with that of Ru metal supported on alumina. Ba 3NiRuTaO 9 adopts the 6H hexagonal perovskite structure (α = 5.754(3)Å, c = 14.119(9)Å). At 900°C it can facilitate 95% conversion of CH 4 with a 98% selectivity for synthesis gas formation and at 800°C it catalyses the total conversion of C 2H 6 with a 94% selectivity for synthesis gas formation. When a mixed CH 4/C 2H 6/O 2 stream flows over this oxide at 900°C, selective oxidation of ethane to synthesis gas is observed. The bulk structure of the perovskite catalyst remains unchanged, and no carbon deposition is observed during the course of these reactions. Although supported Ru metal gives a catalytic performance similar to that of Ba 3NiRuTaO 9, it also catalyses carbon formation when higher hydrocarbons, e.g. ethane, are present.

Control of product selectivity in the partial oxidation of methane

WITH the continuing need to identify new ways of synthesizing transportation fuels and hydrocarbon-based chemicals that do not rely on petroleum products, considerable effort is being devoted to the catalytic partial oxidation of natural gas. A number of oxide and other catalysts have been identified that facilitate oxida-tive coupling of methane to give ethane and ethene as the major products1. But although ethene is valuable as a monomer for polymerization, C2 hydrocarbons are of only limited usefulness. C1 oxygenates, particularly methanol and formaldehyde, are key petrochemical intermediates, but efforts to produce them catalyti-cally by direct methane oxidation have met with little success. Here we show that the selectivity of methane oxidation on magnesium oxide can be switched from C2 hydrocarbons to high yields of formaldehyde simply by changing the reaction conditions, without modification of the catalyst. As well as providing insight into the mechanism for selectivity, which depends on the relative concentrations of methyl radicals and molecular oxygen, our results provide a new route to the catalytic formation of formaldehyde.

Bidirectional adiabatic synthesis gas generator

This paper describes a unique reactor for the production of synthesis gas, carbon monoxide and hydrogen, from the catalytic partial oxidation of natural gas with air. The reactor operates near atmospheric pressure with nickel on alumina catalyst at about 800°C. The product synthesis gas has a hydrogen to carbon monoxide mole ratio near two, which is ideal for feed to a Fischer-Tropsch conversion reactor. The reactor operates adiabatically and autothermally, requiring no additional energy for operation other than the exothermic heat of reaction. Waste heat is efficiently recovered using packed bed heat exchangers. Problems of coke formation are effectively eliminated. The two packed beds are situated in the reactor above and below the catalyst bed. The reactor operates in an unsteady-state mode with feed and product gas flow directions periodically reversed. The reactor was tested experimentally on a laboratory scale unit processing about three liters per minute of natural gas and on a large pilot plant processing about 1400 cubic meters per day of natural gas. A mathematical and computer simulation model was developed to describe the reactor and its operation.

Methanol formation at high pressure by the catalyzed oxidation of natural gas and by the sensitized oxidation of methane

A three part study of the partial oxidation of natural gas or methane to methanol was carried out. In the first part, the effect of reactor wall composition on the homogeneous oxidation of natural gas was determined at a pressure of 30 atm (1 atm=1.01325·10 5 Pa) and temperatures of 350–400°C. In the second part, the effect of solid catalysts on the oxidation of natural gas was determined in a heterogeneous system at 30 atm and various temperatures. Finally, the effect of various homogeneous 'sensitizers' on the oxidation of pure methane at 10 atm was evaluated.

Experimental investigation of the high-temperature conversion of natural gas in a reactor with swirling jets

The swirling jet, unlike the straight-flow one, has a wide angle of expansion and high ejection capability, causing quick ignition and stable burning of fuel. It has been established that the use of powerful swirling jets strongly increases the pulsating component of the velocity, thereby increasing the speed of flame spreading in a gas flow. Since increasing the tubulence of a flow increases the number of turbulent eddies of smaller size, a remarkable decrease in chemical reaction time is expected in swirling jets as compared to straight-flow ones. In addition, the relative length of the mixing path in a swirling jet is almost three times greater than that in a straight-flow jet, indicating a greater capacity for heat and mass transfer in the swirling jet. To substantiate these considerations, an experimental investigation of the high-temperature partial oxidation of natural gas in a laboratory reactor with swirling jets was conducted without preliminary mixing of the reacting masses. Quite encouraging results have been obtained.