Methane quantity

Direct measurement of in situ methane quantities in a large gas-hydrate reservoir. Nature, 385, 426. 

The two binders, the ENG and the thermoplastic polymer, are inert concerning the methane adsorption. The methane quantity delivered depends only on the activated carbon adsorption isotherm and its apparent density in the adsorbent composite block (Table 1). For pure methane, the quantity delivered at 298K between 3.5 and 0.1 MPa is equal to 89 (v/v). 

Here N is the methane quantity in moles V is the volume of the reaction zone r is the contact time. 

With the published laboratory data, strong support is obtained for Darcy flow to be the mechanism driving gas through rocks. Additionally the boundary condition put on the migration process by the evidence in Fig. 2 is fulfilled Darcy flow requires a strict dependency of methane quantities stored in reservoirs on those generated over the same area and on the thickness of seals. 

Emission rates were calculated from the slopes of the lines on the methane vs. time plots or the final accumulated methane quantity. For diffusion, which is relatively constant for an individual 30-45 min collection, the slope can be multiplied by a constant factor to get emissions per minute (or per hour, day, month or year). Thus, instrument signal increases over a given time (ppm methane per minute) and can be multiplied by a factor (14.7, see Leventhal, 1992) to convert to mg/m /day for each time interval (or for the entire 30-45 min experiment) for which there is a set of measurements, based on the area and volume of the collection chamber. 

The Reid vapor pressure is generally barely different from the true vapor pressure at 37.8°C if the light gas content —methane, ethane, propane, and butane— of the sample is small, which is usually the case with petroleum products. The differences are greater for those products containing large quantities of dissolved gases such as the crude oils shown in Table 4.13. 

Large quantities are now manufactured by the reaction between sulphur vapour and methane at a temperature of 900-1000 K in the presence of a clay catalyst ... 

Conformational free energy simulations are being widely used in modeling of complex molecular systems [1]. Recent examples of applications include study of torsions in n-butane [2] and peptide sidechains [3, 4], as well as aggregation of methane [5] and a helix bundle protein in water [6]. Calculating free energy differences between molecular states is valuable because they are observable thermodynamic quantities, related to equilibrium constants and... 

Termination steps are m general less likely to occur than the propagation steps Each of the termination steps requires two free radicals to encounter each other m a medium that contains far greater quantities of other materials (methane and chlorine mol ecules) with which they can react Although some chloromethane undoubtedly arises via direct combination of methyl radicals with chlorine atoms most of it is formed by the propagation sequence shown m Figure 4 21... 

A flame-ionization, total hydrocarbon analyzer determines the THC, and the total carbon content is calculated as methane. Other methods include catalytic combustion to carbon dioxide, which may be deterrnined by a sensitive infrared detector of the nondispersive type. Hydrocarbons other than methane and acetylene are present only in minute quantities and generally are inert in most appHcations. 

Landfill G as Recovery. This process has emerged from the need to better manage landfill operations. Landfill gas is produced naturally anaerobic bacteria convert the disposed organic matter into methane, carbon monoxide, and other gases. The quantity of methane gas is substantial and could be utilized as fuel, but generally is not. Most of the methane simply leaks into the surrounding atmosphere. 

Potential Processes. Sulfur vapor reacts with other hydrocarbon gases, such as acetjiene [74-86-2] (94) or ethylene [74-85-1] (95), to form carbon disulfide. Higher hydrocarbons can produce mercaptan, sulfide, and thiophene intermediates along with carbon disulfide, and the quantity of intermediates increases if insufficient sulfur is added (96). Light gas oil was reported to be successflil on a semiworks scale (97). In the reaction with hydrocarbons or carbon, pyrites can be the sulfur source. With methane and iron pyrite the reaction products are carbon disulfide, hydrogen sulfide, and iron or iron sulfide. Pyrite can be reduced with carbon monoxide to produce carbon disulfide. 

The methanation reaction is currently used to remove the last traces (<1%) of carbon monoxide and carbon dioxide from hydrogen to prevent poisoning of catalysts employed for subsequent hydrogenation reactions. Processes for conversion of synthesis gas containing large quantities of carbon monoxide (up to 25%) into synthetic natural gas have been investigated to serve plants based on coal-suppHed synthesis gas. 

A representative technical grade of methyl chloride contains not more than the following indicated quantities in ppm of impurities water, 100 acid, such as HCl, 10 methyl ether, 20 methanol, 50 acetone, 50 residue, 100. No free chlorine should be detectable. Traces of higher chlorides are generally present in methyl chloride produced by chlorination of methane. The boiling point should be between —24 and —23° C, and 5—95% should distill within a range of about 0.2°C. It should be clear, colorless, and free from visible impurities. 

In the known absence of bromoform, iodoform, chloral, and other halogenated methanes, the formation of phenyhsonitrile with aniline provides a simple and faidy sensitive but nonspecific test for the presence of chloroform, the carbylamine test. Phenyhsonitrile formation is the identification test given in the British Pharmacopoeia. A small quantity of resorcinol and caustic soda solution (10% concentration) added to chloroform results in the appearance of a yellowish red color, fluorescing yeUow-green. When 0.5 mL of a 5% thymol solution is boiled with a drop of chloroform and a small quantity of potassium hydroxide solution, a yellow color with a reddish sheen develops the addition of sulfuric acid causes a change to brilliant violet, which, diluted with water, finally changes to blue (33). 

Chlorination of Hydrocarbons or Chlorinated Hydrocarbons. Chlorination at pyrolytic temperatures is often referred to as chlorinolysis because it involves a simultaneous breakdown of the organics and chlorination of the molecular fragments. A number of processes have been described for the production of carbon tetrachloride by the chlorinolysis of various hydrocarbon or chlorinated hydrocarbon waste streams (22—24), but most hterature reports the use of methane as the primary feed. The quantity of carbon tetrachloride produced depends somewhat on the nature of the hydrocarbon starting material but more on the conditions of chlorination. The principal by-product is perchloroethylene with small amounts of hexachloroethane, hexachlorobutadiene, and hexachloroben2ene. In the Hbls process, a 5 1 mixture by volume of chlorine and methane reacts at 650°C the temperature is maintained by control of the gas flow rate. A heat exchanger cools the exit gas to 450°C, and more methane is added to the gas stream in a second reactor. The use of a fluidi2ed-bed-type reactor is known (25,26). Carbon can be chlorinated to carbon tetrachloride in a fluidi2ed bed (27). 

The mixed refrigerant cwcle was developed to meet the need for hq-uefying large quantities of natural gas to minimize transportation costs of this fuel. This cycle resembles the classic cascade cycle in principle and may best be understood by referring to that cycle. In the latter, the natural gas stream after purification is cooled successively by vaporization of propane, ethylene, and methane. Each refrigerant may be vaporized at two or three pressure levels to increase the natural gas coohng efficiency, but at a cost of considerable increased process complexity. 

The previous volume measurement was done by methane because this does not react and does not even adsorb on the catalyst. If it did, the additional adsorbed quantity would make the volume look larger. This is the basis for measurement of chemisorption. In this experiment pure methane flow is replaced (at t = 0) with methane that contains C = Co hydrogen. The hydrogen content of the reactor volume—and with it the discharge hydrogen concentration— increases over time. At time t - t2 the hydrogen concentration is C = C2. The calculation used before will apply here, but the total calculated volume now includes the chemisorbed quantity. 

This concept is now applied to the liquefaction of methane initially at atmospheric pressure and 105°F, 105°F being selected because it is a common industrial heat rejection temperature. The theoretical quantity of work (expressed in Btu of work equal to 778 ft-lb, of work) required to cool 1 lb of methane down to its liquefaction point and then to absorb the 219.7 Btu of latent heat of liquefaction at -258°F, is shown in Figure 3-2. It amounts to 510.8 Btu of work per pound of methane and is not to be confused with Btu of heat, although the quantities in this case are not very different. This amount of work per pound of methane is equivalent to 352 hp/MMcfd. An actual process with its expected inefficiencies would require twice this much work. 

From isotherm measurements, usually earried out on small quantities of adsorbent, the methane uptake per unit mass of adsorbent is obtained. Sinee storage in a fixed volnme is dependent on the uptake per unit volume of adsorbent and not on the uptake per unit mass of adsorbent, it is neeessary to eonvert the mass uptake to a volume uptake. In this way an estimate of the possible storage capacity of an adsorbent can be made. To do this, the mass uptake has to be multiplied by the density of the adsorbent. Ihis density, for a powdered or granular material, should be the packing (bulk) density of the adsorbent, or the piece density if the adsorbent is in the form of a monolith. Thus a carbon adsorbent which adsorbs 150 mg methane per gram at 3.5 MPa and has a packed density of 0.50 g/ml, would store 75 g methane per liter plus any methane which is in the gas phase in the void or macropore volume. This can be multiplied by 1.5 to convert to the more popular unit, V/V. 

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