Hydrocarbons in natural gas

Eiceman, G.A., B. Davani, M.E. Wilcox, J.L. Gardea, and J.A. Dodson. 1985. High molecular weight hydrocarbons including polycyclic aromatic hydrocarbons in natural gas from consumer distribution pipelines and in pipeline residue. Environ. Sci. Technol. 19 603-608. 

Steam, at high temperatures (975-1375 K) is mixed with methane gas in a reactor with a Ni-based catalyst at pressures of 3-25 bar to yield carbon monoxide (CO) and hydrogen (H ). Steam reforming is the process by which methane and other hydrocarbons in natural gas are converted into hydrogen and carbon monoxide by reaction with steam over a nickel catalyst on a ceramic support. The hydrogen and carbon monoxide are used as initial material for other industrial processes. 

The higher hydrocarbons in natural gas also react with steam in a similar way according to the reaction... 

Oil, or petroleum, is a liquid mixture of medium-length hydrocarbons (shorter than the hydrocarbons in coal, but longer than the hydrocarbons in natural gas). It is usually black or dark brown and has a strong smell, but the characteristics of oil vary greatly, depending on its specific ingredients. 

The location of the CO peak indicates the temperature regime for onset of fast oxidation for each hydrocarbon. At the reaction conditions of the flow reactor, the characteristic temperature regime for oxidation differs widely between fuels. Compared to methane, the C2 hydrocarbons are consumed at much lower temperatures at a given reaction time. This is consistent with the general observation that the C2 hydrocarbons have quite different ignition characteristics compared to methane [427]. As a consequence the presence of ethane (C2H6) and higher hydrocarbons in natural gas has a considerable influence on induction times. 

The separation of methane from higher hydrocarbons in natural gas for safer and... 

Light Hydrocarbons Separation Technologies Site covers proprietary, non-cryogenic, absorption based technology for separation of light hydrocarbons in natural gas, refining and petrochemicals industries, httii.llwww.aet.com. 

The two prevailing concepts on the origin and sources of natural gas and methane, its major constituent, are based on either biological or nonbiological reactions and mechanisms. Both address petroleum and, coincidentally, natural gas because the methane and other light hydrocarbons in natural gas are also constituents of most petroleum as produced. The mounting evidence for nonbiological methane and natural gas is briefly discussed below. 

In recent years the shortage of both ethylene and ethylene feedstocks has resulted in a search for alternate sources of these two commodities. Methane is an obvious choice, since it comprises up to 85 mole 7 of the hydrocarbons in natural gas. 

The catalyst should have high activity for the oxidation of methane and other hydrocarbons in natural gas in order to obtain ignition at temperatures close to the compressor outlet temperature. At the same time the catalyst should maintain high surface area at the operating temperature. 

In a partial oxidation process, methane and other hydrocarbons in natural gas are combined with a limited amount of oxygen (typically, from air) that is not enough to completely oxidize the hydrocarbons to carbon dioxide and water. With less than the stoichiometric amount of oxygen available for the reaction, the reaction products contain primarily hydrogen and carbon monoxide (and nitrogen, if the reaction is carried out with air rather than pure oxygen) and a relatively small amount of carbon dioxide and other compounds. Subsequently, in the WGS reaction, the carbon monoxide reacts with water to form carbon dioxide and more hydrogen. 

Gelpi, E. and J. Or6 Ubiquity of hydrocarbons in nature Gas chromatographic-mass spectrometric determination of the hydrocarbons in cigarette smoke condensate J. Chromatog. Sci. 8 (1970) 210-213. 

When chromatographic separations (7) are operated in a batch mode, a portion of the mixture to be separated is introduced at the column inlet. A solute-free carrier fluid is then fed continually through the column, the solutes separating into bands or zones. Some industrial operations such as mixed-vapor solvent recovery and sorption of the less volatile hydrocarbons in natural gas or natural gasoline plants are being carried out on pilot plant and semiworks scales. Continuous countercurrent systems designed along the basic principles of distillation columns have been constructed. 

Rapidly repeated sampling of major hydrocarbons in natural gas pipeline... 

The constituents of natural gas should not have deleterious effects on the pipe properties, nor should the gas diffuse through the pipe wall at an excessive rate. Methane and the other hydrocarbons in natural gas, diffuse through polyethylene at a very low rate, that neither causes economic loss, nor dangerous build-up of gas on the outside of the pipe. The maximum daily loss from 1 km of pipe, of 90 mm outer diameter and wall thickness 8.5 mm, pressurised to 1 bar pressure (the partial pressure of methane is 2 bar inside and Obar outside), is 4.41. This is less than 1% of the losses that occur with jointed cast iron pipe, and can be compared with a daily throughput of 2 x 10 1 of gas for a pressure drop of 1 mbar km . ... 

In a partial oxidation process, methane and other hydrocarbons in natural gas react exothermically with less than stoichiometric oxygen to produce carbon monoxide and hydrogen. Typically, the partial oxidation of natural gas is much faster than steam reforming and, therefore, requires smaller reactors. Partial oxidation reactions are given as follows [1] ... 

Dew-point adjustment (see Fig. 7.10) serves the reduction of the concentration of water and heavy hydrocarbons in natural gas to such an extent that no condensation occurs during the ensuing transport in the pipeline. This would lead to a multiphase flow that places higher demands on the design and laying of the pipelines. 

CO + H2O = CO2 + H2 Higher hydrocarbons in natural gas, LPG or liquid hydrocarbons will react in a similar way ... 

Separation of CO2 from hydrocarbons CO2 separated from light hydrocarbons in natural gas streams at high pressures CO2 separated from biogas (containing CO2 and methane) CO2 separated from breathing gas mixture. 

FIGURE 11.27 Conceptual diagram of the oxidative prereforming of C2—C4 hydrocarbons in natural gas. (For colour version of this figure, the reader is referred to the online version of this book.)... 

---