Molecular weight Naphthas

Analytical Approaches. Different analytical techniques have been appHed to each fraction to determine its molecular composition. As the molecular weight increases, complexity increasingly shifts the level of analytical detail from quantification of most individual species in the naphtha to average molecular descriptions in the vacuum residuum. For the naphtha, classical techniques allow the isolation and identification of individual compounds by physical properties. Gas chromatographic (gc) resolution allows almost every compound having less than eight carbon atoms to be measured separately. The combination of gc with mass spectrometry (gc/ms) can be used for quantitation purposes when compounds are not well-resolved by gc. 

The molecular weight distribution of the feed affects the distribution of the product. If the naphtha is concentrated in the C -Cg range, more benzene and toluene are found in the product. If the feed is weighted to Cg—C q, more xylenes and higher aromatics are found. Some carbon number "shppage" occurs by dealkylation some C s form benzene by losing a methyl group, some CgS form toluene, etc. 

In the suspension process, which was the first method to be commercially developed, propylene is charged into the polymerisation vessel under pressure whilst the catalyst solution and the reaction diluent (usually naphtha) are metered in separately. In batch processes reaction is carried out at temperatures of about 60°C for approximately 1-4 hours. In a typical process an 80-85% conversion to polymer is obtained. Since the reaction is carried out well below the polymer melting point the process involves a form of suspension rather than solution polymerisation. The polymer molecular weight can be controlled in a variety of... 

Reactor temperature is also a function of the feedstock used. Higher molecular weight hydrocarhons generally crack at lower temperatures than lower molecular weight compounds. For example, a typical furnace outlet temperature for cracking ethane is approximately 800°C, while the temperature for cracking naphtha or gas oil is about 675-700°C. 

The plastic samples used in this study were palletized to a form of 2.8 3.2min in diameter. The molecular weights of LDPE and HDPE were 196,000 and 416,000, respectively. The waste catalysts used as a fine powder form. The ZSM-5 was used a petroleum refinement process and the RFCC was used in a naphtha cracking process. The BET surface area of ZSM-5 was 239.6 m /g, whose micropore and mesopore areas were 226.2 m /g and 13.4 m /g, respectively. For the RFCC, the BET surface area was 124.5 m /g, and micropore and mesopore areas were 85.6 m /g and 38.89 m /g, respectively. The experimental conditions applied are as follows the amount of reactant and catalyst are 125 g and 1.25-6.25 g, respectively. The flow rate of nitrogen stream is 40 cc/min, and the reaction temperature and heating rate are 300-500 C and 5 C/ min, respectively. Gas products were vented after cooling by condenser to -5 °C. Liquid products were collected in a reservoir over a period of... 

The pyrolysis reactor is an important processing step in an olefin plant. It is used to crack heavier hydrocarbons such as naphtha and LPG to lower molecular weight hydrocarbons such as ethylene. The pyrolysis reactor, in this study, consists of two identical sides each side contains four cracking coils in parallel (see Fig. 2). 

The alkyl-substituent pattern for some PAHs series (e.g., alkylnaphthalenes, phenanthrene/anthracene, pyrene/fluoranthene, m/z 228 and m/z 252) are shown in Figs. 6-9, respectively. The parent PAHs and their alkylated homologs are determined in GC-MS data by monitoring their corresponding molecular weights. For example, for the naphthalene series the ions at m/z 128,142 methyl-naphthalenes, 156 C2-naphthalenes, 170 C3-naphthalenes, and 184 C4-naphtha-lenes are monitored (Fig. 6). The GC elution orders of the C2-naphthalene and C3-naphthalene isomers have been reported [144,145]. 

This chapter reviews the adsorptive separations of various classes of non-aromatic hydrocarbons. It covers three different normal paraffin molecular weight separations from feedstocks that range from naphtha to kerosene, the separation of mono-methyl paraffins from kerosene and the separation of mono-olefins both from a mixed C4 stream and from a kerosene stream. In addition, we also review the separation of olefins from a C10-16 stream and review simple carbohydrate separations and various acid separations. 

The gasoline Molex process is the first of three processes since it separates the lowest molecular weight feed of the three Molex normal paraffin separahon processes. Gasoline Molex was developed to optimize a Refiner s octane pool by extracting low octane value normal paraffins (specifically C5, 5) from naphtha. In a typical refinery flow scheme, a gasoline Molex unit is integrated with a catalyhc isomeriza-hon unit (Penex unit) which converts the Molex unit s extracted normal paraffins into desired iso-paraffins. These iso-paraffins are desirable because they possess higher octane value than their linear counterpart. 

In the hydrocracking process, this phenomenon is exploited to shift catalyst selectivity from the naphtha to the distillate products. Here the wide separation of sites is exploited to minimize the potential for secondary cracking in initial products and intermediates. This, along with the introduction of escape routes for the primary product tends to preserve the higher molecular weight hydrocarbons, thereby producing more dishllates [49, 61, 62]. 

Lower molecular weight feedstocks, such as ethane and propane, give a high percentage of ethylene higher molecular weight feedstocks, such as naphtha and gas oil, are used if propylene demand is up. The following table summarizes the typical yields of olefins obtained from various feeds. 

Low fuel viscosity can be due to the presence of low-boiling-point, low-molecular-weight compounds in the fuel. Contamination with low-boiling-point compounds such as solvents, gasoline, and petroleum naphtha can dramatically reduce the viscosity of distillate fuel and residual fuel oil. 

Aluminum Chloride Processing A refining method using aluminum chloride as a catalyst to improve the appearance and odor of steam cracked naphtha streams. Aluminum chloride functions as a catalyst for the polymerization of olefins into higher-molecular-weight, less-problematic compounds. 

Reforming a naphtha to a higher octane rating must involve at least one of the following chemical reactions (a) production of aromatics, (6) production of highly branched paraffins, (c) production of olefins, or (d) lowering the molecular weight of the hydrocarbons in the naphtha. 

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