Hydrocarbon pool

To shed more light on this issue, the steady state of methanol conversion on zeolites HZSM-5, H-SAPO-34, and H-SAPO-18 was characterized by CF MAS NMR spectroscopy under CF reaction conditions (49,261). 

To ensure that meaningful results were obtained by C CF MAS NMR spectroscopy, catalytic experiments were performed with a conventional fixed-bed reactor and, under the same conditions, a spinning MAS NMR rotor reactor. The reaction products from both reactors were analyzed by on-line gas chromatography (261). A comparison of the results showed a reasonably good agreement in particular, the methanol conversion takes place in the same temperature range, and the same qualitative behaviors of the conversion and yield curves were found for the two reactors (261). 

129-134 ppm. Simultaneously, a strong increase in the yields of light alkenes, such as C2 = and C3 =, was observed by on-line gas chromatography. 

For a detailed analysis of the hydrocarbon pool formed under steady-state conditions, a line separation of the C MAS NMR spectra was performed with commercial software such as BRUKER WINFIT (261). The CF MAS NMR signals observed during methanol conversion on H-SAPO-34 at reaction temperatures of 548-673 K were attributed to a mixture of Cg to C12 alkenes and aromatics, such as 3-hexene (131-133, 21 and 15 ppm), 2,5-dimethyl-3-hexene (134-136, 32, and 22 ppm), 2,3-hexadiene (132-134, 126-128, and 18 ppm), alkylated octadienes (133-135, 25, 23, and 15 ppm), cyclopentene (131-133, 33, and 23 ppm), diethylcyclopentene (133-135 ppm and various signals at 14-33 ppm), and 7 -xylene (134, 129, and 21 ppm) (261). Signals at ca. 22 and 129 ppm, retained at 673 K and after purging of the used catalyst at 673 K with dry carrier gas, indicated 

In an attempt to identify the catalytic role of the hydrocarbon pool, the MTO process was further studied by C CF MAS NMR spectroscopy with an alternating flow of CH3OH and After the conversion of V-II3OII under steady- 

In an attempt to identify the catalytic role of the hydrocarbon pool, the MTO process was further studied by CF MAS NMR spectroscopy with an alternating flow of CHsOH and CHsOH. After the conversion of CHsOH under steady-state conditions, the reactant flow was switched to CHsOH without a change the reaction parameters. If the alkyl groups of the hydrocarbon pool were involved in the conversion of methanol, for example, by adding reactant molecules and splitting off product molecules, the C-isotope abundance of these groups would be expected to decrease strongly after the switch from CHsOH to CHsOH. 

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Mudan, K. S. 1984. Thermal radiation hazards from hydrocarbon pool fires. Prog. Energy Combust. Sci. 10 59-80. 

Based on in situ 13C NMR data, surface methoxy groups are reported to form hydrocarbons at temperatures of 523 K and above [273]. The authors have suggested that these hydrocarbons may contribute to the hydrocarbon pool that is established to participate in the catalytic reaction mechanism to form higher hydrocarbons from methanol. Other reactions with amines or halides have also been published [276]. 

Standard Test Method for Fire Test of Through Penetration Fire Stops, 1994. Standard Test Methods for Determining Effects of Large Hydrocarbon Pool Fires on Structural Members and Assemblies, 1993. 

The test pit method consists of excavating a pit using a backhoe to a depth where hydrocarbon pools in the bottom of the pit. Soil samples are subsequently obtained above and below the hydrocarbon-affected zone using hand-driven tubes (acrylic small-diameter shelby tubes). Problems associated with this method include ... 

Recovery of DNAPL is a very slow process that is alfected by those factors encountered with LNAPL (i.e., relative permeability, viscosity, residual hydrocarbon pool distribution, site-specific factors, etc ). Dissolution of a DNAPL pool is dependent upon the vertical dispersivity, groundwater velocity, solubility, and pool dimension. Dispersivities for chamolid solvent are estimated for a medium to coarse sand under laboratory conditions on the order of 1(L3 to 1(H m. Thus, limited dispersion at typical groundwater velocities is anticipated to be slow and may take up to decades... 

LNAPL hydrocarbon pools occurring as perched zones and generally overlying the water table which serves as a continued source of both soil and groundwater contamination. 

The ubiquitous occurrence, areal extent, and estimated volume of major LNAPL hydrocarbon pools beneath these facilities situated on the Los Angeles coastal plain are shown in Ligure 12.25. Lor purposes of this discussion, a pool is defined as an areally continuous accumulation of LNAPL. Two or more pools that have distinct differences in their respective physical and chemical properties are referred to as coalesced pools. Individual accumulations of relatively uniform product are referred to as subpools, since it is inferred that they have coalesced to form areally continuous occurrences. The occurrence of several pools and subpools at a particular site reflects releases from multiple sources at various times. The combined areal extent of these LNAPL pools is on the order of 1500 acres. The estimated cumulative minimum volume is on the order of approximately 1.5 million barrels an estimated cumulative maximum volume is on the order of 7.5 million barrels. The discrepancy in LNAPL hydrocarbon volume reflects varying methodologies involved in the estimates. 

J.F. (2004) Theoretical smdy of the methylbenzane side-chain hydrocarbon pool mechanism in methanol to olefin catalysis. /. Am. Chem. Soc., 126, 2991-3001. 

Storage tanks can be treated as a confined pool fire. For confined pools that have a significant level of material, Table 5-2 shows the burning rate in inches per hour for a variety of materials. When first ignited, the fire spreads rapidly across the full extent of the hydrocarbon pool and proceeds to consume the liquid at a characteristic burning rate (Spouge, 1999). 

If the concrete member is designed to have 4-hour fire resistance in a cel-lulosic fire test, as recommended in design guidance by the Institute of Structural Engineers and the Concrete Society, then 3-hour fire resistance would be expected in hydrocarbon pool fires, provided that spalled material remained in place (Spouge, 1999). 

The UL 2085 tank construction is intended to limit the heat transferred to the primary tank when the AST is exposed to a 2-h hydrocarbon pool fire of 1093°C (2000°F). The tank must be insulated to withstand the test without leakage and with an average maximum temperature rise on the primary tank not exceeding 2TC (260 F). Temperatures on the inside surface of the primary tank cannot exceed 204°C (400°F). 

SwRI 97-04, Standard for Fire Resistant Tanks, includes tests to evaluate the performance of ASTs under fire and hose stream. This standard is similar to UL 2080 in that the construction is exposed to a 2-h hydrocarbon pool fire of 1093°C (2000°F). However, SwRI 97-04 is concerned only with the integrity of the tank after the 2-h test and not concerned with the temperature inside the tank due to the heat transfer. As a result, UL 142 tanks have been tested to the SwRI standard and passed. Secondary containment with insulation is not necessarily an integral component of the system. 

B.2. Simultaneous Characterization of the Formation of Hydrocarbon Pool Compounds on Acidic Zeolites by MAS NMR- UV/Vis Spectroscopy... 

The reaction diagram of Fig. 14.1 applies to methane oxidation under both flame [423] and flow reactor [146] conditions. At high temperatures and fuel-lean to stoichiometric conditions, the conversion of methane proceeds primarily through the sequence CH4 -> CH3 -> CH2O -> HCO -> CO -> CO2. At lower temperatures or under fuel-rich conditions the reactions of CH3 with O or O2 are less competitive. Under these conditions two CH3 radicals may recombine and feed into the C2 hydrocarbon pool,... 

Thermal radiation hazards result from liquid hydrocarbon pool fires, flash fires, turbulent jet fires, and fireballs (BLEVE). A release may be ignited immediately or some time later, and the ignition source may be at the point of release or at a distance downwind, as shown in Figure 2.2. Gas venting... 

B A "hydrocarbon pool"-type mechanism which In a somewhat oversimplified form may be represented by scheme 1. 

In the Dampier sub-basin no such statistical relationship between hydrocarbon pools and major carbonate-cemented zones is known in Angel Formation reservoirs. 

In both fields, wireline log correlation shows that the major carbonate-cemented zones share the following characteristics (i) they are found in clean stacked sandstone sequences (ii) they occur in discrete layers, separated by porous sandstone intervals (iii) they are intimately associated with hydrocarbon pools (iv) the thickness and relative spatial configuration of the carbonate-cemented zones vary over relatively short distances and are unrelated to facies controls (Figs 9 and 16). The major difference between the carbonate-cemented zones in each field is their stratigraphical position in relation to the hydrocarbon pools. In the Gidgealpa Field, the calcite-cemented zones occur below the oil-water contact in the lower and middle portions of the Namur Sandstone, in a stacked sandstone sequence (Fig. 16). In the Angel Field, the dolomite-cemented zones occur in the upper part of a massive sandstone sequence (Fig. 9), both below and above the... 

Carbonate cement haloes associated with hydrocarbon pools are well documented, and commonly attributed to the microbial oxidation of crude oil or methane in different geological settings (Gould Smith, 1978 Smith, 1978 Faber Stahl, 1984 Oehler Sternberg, 1984 Hovland et al., 1987 O Brien Woods, 1995). However, a number of observations point towards this type of precipitation mechanism not being appropriate in the context of the Angel Field and Gidgealpa Field areas ... 

In the Eromanga basin this conclusion is supported by the strong statistical correlation between the occurrence of major calcite-cemented zones and oil pools in Jurassic sandstones. This concept is particularly valuable if a correlation can be proved between the size of the hydrocarbon pools and the size of the carbonate cement volume (intensity and areal extent of high-amplitude events). 

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