Hydrocarbons selective

The behavior of the diesel fuel is compared to that of two pure hydrocarbons selected as a reference J... 

The hydrocarbons selected were heptane, cyclohexane, and toluene one such mixture is now specified within the fluids for liquid aging assessments according to Norwegian NORSOK M-710 Rev. 2 standard for qualification of offshore duty elastomer seals. 

Another complicating characteristic of materials from the environment is that the size and nature of the residue to be analyzed in the mass spectrometer will change from sample to sample. To determine if this might have an effect on the observed TCDD signal, we analyzed identical samples of TCDD with differing amounts of squalane, a saturated hydrocarbon selected as a model for residues obtained from standard extraction and cleanup procedures. As is indicated in Table I (Part A), there was... 

However, it was generally found that the total C2 hydrocarbon selectivity decreases drastically with increasing conversion of methane, so that Yc2 (the total C2 hydrocarbon yield) was always found, until very recently, to be less than 30% [1-9]. Achieving C2 hydrocarbon yield in excess of 50% is a necessary requirement for the development of an economically viable industrial process. 

The effect of CH4 conversion on the total C2, C2H4, C2He hydrocarbon selectivity and yield is shown in detail on Figure 4 for the case of I=5mA. 

Figure 4. Effect of methane conversion for 1=5 mA on ethylene, ethane and total Cg hydrocarbon selectivity and yield. Lines from kinetic model discussed below. Solid lines CgH j and C2Hg Dashed lines C2...

Table 10.3. Mechanism proposed for depicting the H2 assisted hydrocarbon selective catalytic reduction of NO over Ag/Al203 (reproduced with permission from Ref. [78])...

Bertole, C. J., Kiss, G., and Mims, C. A. 2004. The effect of surface-active carbon on hydrocarbon selectivity in the cobalt-catalyzed Fischer-Tropsch synthesis. J. Catal. 223 309-18. 

The use of a Fischer-Tropsch (FT) process to produce long-chain hydrocarbons is well known in industry, and achieving the desired selectivity from the FT reaction is crucial for the process to make economic sense. It is, however, well known that a one-alpha model does not describe the product spectrum well. From either a chemicals or fuels perspective, hydrocarbon selectivity in the FT process needs to be thoroughly understood in order to manipulate process conditions and allow the optimization of the required product yield to maximize the plant profitability. There are many unanswered questions regarding the selectivity of the iron-based low-temperature Fischer-Tropsch (Fe-LTFT) synthesis. 

Van der Laan, G.P., Beenackers, A.A.C.M. 1999. Hydrocarbon selectivity model for the gas-solid Fischer-Tropsch synthesis on precipitated iron catalysts. Ind. Eng. Chem. Res. 38 1277. 

The results of the experiments, in terms of both CO conversion and light hydrocarbons selectivity, are shown in Figure 16.6a. As expected, CO conversion strongly decreases upon increasing space velocity. Moreover, a slight increase of methane selectivity is also observed, while selectivity to C5+, C25+, and olefinic... 

Notably, with a single set of rate parameter estimates, the present model can also correctly describe the effects of all the investigated process conditions on product distribution. Figure 16.10 compares experimental and calculated ASF product distributions in five of the investigated process conditions. It is worth noticing also that the model predicts the hydrocarbons selectivity up to n = 49,... 

Figure 5. The influence of the Ru particles size on the hydrocarbon selectivities Curve 1, distribution for a mean-particle size of 1.5 nm Curve 2, distribution for a mean-particle size of 10 nm initial pressure, 20 bar HJCO = 4/1 reaction temperature,200°C...

Effect of Pressure The results are listed in Table IV. The effect of pressure on conversions and selectivities are shown in Figure 1. The CO conversion increased from 63% at 13.6 atm (200psig) to 90% at 75 atm (llOOpsig). The hydrocarbon selectivity, defined as (total carbon converted - total carbon in CO ) f total carbon converted, remained steady at 97%. the rest of 3% being converted to CO. The selectivity of Cc increased with increasing pressure while the aromatics in decreased. The C -KL make was substantially reduced by higher pressure, for example, from 59% at 13.6 atm to 29% at 74 atm. 

Hydrocarbon Selectivity based on H202 (%)a 2/3 ratiob Product distribution (mol%) ... 

At present the most effective available after-treatment techniques for NO, removal under lean conditions are ammonia selective catalytic reduction (SCR) [1-3] and NO, storage reduction (NSR) [4—6]. Indeed, three-way catalysts (TWCs) are not able to reduce NO, in the presence of excess oxygen, because they must be operated at air/ fuel ratios close to the stoichiometric value. Also, non-thermal plasma (NTP) and hydrocarbon-selective catalytic reduction (HC-SCR) are considered, although they are still far from practical applications. 

Polycyclic aromatic hydrocarbons, selected non-heterocycllc (No. 202,1998) Progeny, principles for evaluating health risks associated with exposure to chemicals during pregnancy (No. 30,1984)... 

The halogen compounds used were methylene dichloride, chloroform, carbon tetrachloride, ethylene dichloride, ethyl bromide, ethylene dibromide, bromoform, methyl iodide, and ethyl iodide. The hydrocarbons selected for their interesting combustion properties were hexane, 2-methylpentane, 2,2-dimethylbutane, hex-l-ene, heptane, methylcyclo-hexane, isooctane, diisobutylene, benzene, toluene, m-xylene, and ethylbenzene. 

The common method used for preparing complexes of all these ligands has been the direct reaction between a metal salt and the ligand in a non-aqueous solvent such as an alcohol, acetone or halogenated hydrocarbon, selected according to the solubility of the metal salt. Triethyl orthoformate or 2,2 -dimethoxypropane have been added as an internal desiccant where necessary, because water is a competitive ligand in these systems, and where crystallization was not spontaneous it has been induced by addition of hydrocarbons or diethyl ether. 

A typical flow diagram of a membrane system for C3+ liquids recovery is also shown in Figure 8.34. The natural gas is fed to modules containing a higher-hydrocarbon-selective membrane, which removes the higher hydrocarbons as the permeate stream. This stream is recompressed and cooled by a cold-water exchanger to condense higher hydrocarbons. The non-condensed bleed... 

Membrane system using C3+ hydrocarbon-selective membranes... 

Figure 8. Light hydrocarbon selectivity of hydrothermally pretreated...

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