Natural gas compositions

Because the synthesis reactions are exothermic with a net decrease in molar volume, equiUbrium conversions of the carbon oxides to methanol by reactions 1 and 2 are favored by high pressure and low temperature, as shown for the indicated reformed natural gas composition in Figure 1. The mechanism of methanol synthesis on the copper—zinc—alumina catalyst was elucidated as recentiy as 1990 (7). For a pure H2—CO mixture, carbon monoxide is adsorbed on the copper surface where it is hydrogenated to methanol. When CO2 is added to the reacting mixture, the copper surface becomes partially covered by adsorbed oxygen by the reaction C02 CO + O (ads). This results in a change in mechanism where CO reacts with the adsorbed oxygen to form CO2, which becomes the primary source of carbon for methanol. 

Fig. 1. Fquilihrium conversion of carbon oxides to methanol based on reformed natural gas composition of 73% H2, 15% CO, 9% CO2, and 3% CH ...

Example 1. A pseudo single compound is generated for the natural gas composition in Table 1. 

The first step in the production of synthesis gas is to treat natural gas to remove hydrogen sulfide. The purified gas is then mixed with steam and introduced to the first reactor (primary reformer). The reactor is constructed from vertical stainless steel tubes lined in a refractory furnace. The steam to natural gas ratio varies from 4-5 depending on natural gas composition (natural gas may contain ethane and heavier hydrocarbons) and the pressure used. 

In a test on a furnace fired with natural gas (composition 95 per cent methane, 5 per cent nitrogen) the following flue gas analysis was obtained carbon dioxide 9.1 per cent, carbon monoxide 0.2 per cent, oxygen 4.6 per cent, nitrogen 86.1 per cent, all percentages by volume. 

Bruner, F. H. 1949. Synthetic gasoline from natural gas. Composition and quality. Ind. Eng. Chem. 41 2511-15. 

Thus, the higher heating value for the specified natural gas composition is 285.6 Btu/ft. ... 

Natural gas composition varies from field to field. The main component of purified natural gas generally is methane ( 90 %+) along with other light hydrocarbons. Hence, hydrate formation conditions and the hydrates obtained may vary according to gas composition. Obviously, each component interacts differently with water and hence there will... 

In the discussion appendix of the original paper by Carson and Katz (1942), Hammerschmidt indicated that, while the method was acceptable for gases of normal natural gas composition, an unacceptable deviation was obtained for a gas rich in ethane, propane, and the butanes. More work is also required to revise the Kvs -value charts for two components, namely, carbon dioxide and nitrogen. In three-phase hydrate data for binary mixtures of carbon dioxide and propane, Robinson and Mehta (1971) determined that the Kvs method for carbon dioxide gave unsatisfactory results. The API Data Book shows the Kvs values for nitrogen to be only a function of pressure, without regard for temperature Daubert (Personal... 

Table 4 Heating values calculation for a given natural gas composition...

Synthetic gas can be produced from a variety of feedstocks. Natural gas is the preferred feedstock when it is available from gas fields (nonassociated gas) or from oil wells (associated gas). The first step in the production of synthesis gas is to treat natural gas to remove hydrogen sulfide. The purified gas is then mixed with steam and introduced to the first reactor (primary reformer). The reactor is constructed from vertical stainless steel tubes lined in a refractory furnace. The steam to natural gas ratio is 4—5 depending on natural gas composition (natural gas may contain ethane and heavier hydrocarbons) and the pressure used. A promoted nickel-type catalyst contained in the reactor tubes is used at temperature and pressure ranges of 700 800°C and 30—50 atm, respectively. The product gas from the primary reformer is a mixture of H2, CO, C02, unreacted CH4, and steam. The main reforming reactions are ... 

If a process gas is supplied to the cathode with an H,S level of 2000 ppm, a CO, level of 1%, and an H,0 level of 12% (a saturated natural gas composition), it is assumed that 99% of the H,S is removed by reaction (5), and if the process and sweep gas flowrates are equal, then there exist an activity ratio of a oJa of 665 in the anolyte before significant (e.g. 1%) of the carbonate is oxidized. This assiunes equivalent electrode kinetics for the cathodic and anodic reactions. When compared to the activity ratio of Ocos a of 26.9, this shows the thermodynamic preference for the oxidation of to elemental sulfur by equation (8) when there is an absence of reductant at the anode. This mode of operation is preferable for commercial application, with direct production of elemental sulfur vapor, eliminating this need for a Claus reactor for sulfur production. The net effect, under these conditions, is continuous removal of H,S from the process gas accompanied by enrichment of the process gas with H, and direct generation of elemental sulfrur. ITie only reagent required is electric power at a potentially attractive rate, which will be shown. 

Variability of Natural Gas Composition in Select Major Metropolitan Areas of the United States", Interim Report of the Gas Research Institute, August 1990 - March 1991. 

Error ealeulated for eaeh imnormalized component mol % shall be less than 1% or for the smallest component the differenee between peak heights shall be less than 1 nun. The sirm of all urmormalized component mol % shall be 100 1%. The unnormalized component mol % are then averaged and the final sample eomposition is obtained by normalizing to total of 100%. Attached table 4 is an example of caleulation method for natural gas composition analysis. 

Natural gas composition and pressure use that available at the sight of your plant. If no data can be found, use the data below ... 

In ammonia-urea complexes where all of the ammonia is used to make urea, the amount of CO2 derived from methane feedstock may not be sufficient for the urea plant needs. Urea requires a C02 NH3 ratio of 1 2 whereas, the production of ammonia by reforming pure methane results in a C02 NH3 ratio of 7 16. In this case it would be advantageous if the natural gas contained enough higher hydrocarbons to supply enough CO2 for urea production. This is often the case as shown by the example of natural gas composition given in Table 6.4. 

Dissociation point measurements were conducted with the natural gas (composition given in Table 1) in the presence of distilled water and MEG solutions using the isochorie step-heating method. The dissociation data are tabulated in Tables 5-7 and plotted in Fig. 3. The experimental measurements are in good agreement with the predictions of the thermodynamic model. 

Some components risually found in natural gas in combination of water can cause hydrate formation. Hydrate formation is one of the problems facing the production, processing and transportation of natural gas [1]. To predict the hydrate formation, it is essential to calculate the pressure-temperature curve for natural gas composition. Table 3 gives the natural gas composition used in Tehran gas network. 

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