Paraffins light

Search for New Catalytic Materials for Isomerization of Light Paraffin 

The hydroisomerization of light paraffins (C5-C6-C7) to produce their branched isomers is an important industrial process aimed at improving the octane number of the light straight mm stream (LSR). Reformulated gasolines with their impact on olefins and aromatics reduction [26, 27] have increased the number of LSR isomerization units. Table 5.1 gives the octane number of the different C5-C7 linear and branched paraffins. 

Considering the available technologies for isomerization, it would be interesting to develop a new generation of environmentally friendly catalysts with high activity and selectivity to branched isomers that can work at lower reaction temperatures than zeolites and show an increased resistance to sulfur and water. 

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The complexity of petroleum products raises the question of sample validity is the sample representative of the total flow The problem becomes that much more difficult when dealing with samples of heavy materials or samples coming from separations. The diverse chemical families in a petroleum cut can have very different physical characteristics and the homogeneous nature of the cut is often due to the delicate equilibrium between its components. The equilibrium can be upset by extraction or by addition of certain materials as in the case of the precipitation of asphaltenes by light paraffins. 

Deasphalting is a liquid-liquid separation operation that extracts the last of the easily convertible hydrocarbons from the vacuum residue. Solvents enipl ec) are light paraffins propane, butane, and pentane. The yimd In deasphalted oil increases with the molecular weight of the solvent, but its quality decreases. 5 uxct... 

The mercury-sealed stirrer may be replaced by a Kyrides stirrer (Fig. II, 7, 12) formed from a P.V.C. gland and lubricated with a mixture of vaseline and light paraffin. The continuous passage of nitrogen may be dispensed with if a fairly wide tube dipping into a little mercury is connected to the top of the condenser the latter serves to retain the nitrogen atmosphere. 

Mobil s High Temperature Isomerization (MHTI) process, which was introduced in 1981, uses Pt on an acidic ZSM-5 zeoHte catalyst to isomerize the xylenes and hydrodealkylate EB to benzene and ethane (126). This process is particularly suited for unextracted feeds containing Cg aHphatics, because this catalyst is capable of cracking them to light paraffins. Reaction occurs in the vapor phase to produce a PX concentration slightly higher than equiHbrium, ie, 102—104% of equiHbrium. EB conversion is about 40—65%, with xylene losses of about 2%. Reaction conditions ate temperature of 427—460°C, pressure of 1480—1825 kPa, WHSV of 10—12, and a H2/hydtocatbon molar ratio of 1.5—2 1. Compared to the MVPI process, the MHTI process has lower xylene losses and lower formation of heavy aromatics. 

Patents cover a new reforming catalyst based on L-zeoHte which gives a significantly higher yield of BTX, especially benzene, from light paraffinic feeds (11). Other new zeoHtes (12) may also offer advantages over the traditional reforming catalyst supports. 

Evaporative emissions from vehicle fuel systems have been found to be a complex mixture of aliphatic, olefinic, and aromatic hydrocarbons [20,24,33]. However, the fuel vapor has been shown to consist primarily of five light paraffins with normal boiling points below 50 °C propane, isobutane, n-butane, isopentane, and n-pentane [33]. These five hydrocarbons represent the more volatile components of gasoline, and they constitute from 70 to 80 per cent mass of the total fuel vapor [24,33]. 

Extracts (petroleum), heavy naphthenic distillate solvent Extracts (petroleum), heavy paraffinic distillate solvent Extracts (petroleum), light naphthenic distillate solvent Extracts (petroleum), light paraffinic distillate solvent Extracts (petroleum), light vacuum gas oil solvent Euel oil no. 6... 

Glycol.diacetate.. . Glycol diformate., , Heat transfer oils Heavy paraffinic. Light paraffinic.. 

The main route for producing light olefins, especially ethylene, is the steam cracking of hydrocarbons. The feedstocks for steam cracking units range from light paraffinic hydrocarbon gases to various petroleum fractions and residues. The properties of these feedstocks are discussed in Chapter 2. 

According to Le Chatelier s principle, conversion is increased by increasing the temperature and decreasing the pressure. Figure 6-3 shows the effect of temperature on the dehydrogenation of different light paraffins. ... 

Figure 6-3. Effect of temperature on the dehydrogenation of light paraffins at one atmosphere." ...

Interest in the use of lower-value light paraffins for the production of aromatics led to the introduction of two new processes similar to the Cyclar process, the Z-forming and the Aroformer processes, which were developed in Japan and Australia, respectively/ ... 

Distillates (petroleum), acid-treated light paraffinic... 

Synonym(s) o-Tolyl phosphate TOCP TOTP Petroleum distillates solvent-refined light paraffinic Petroleum distillates, straight-run middle... 

Serra, J.M., Chica, A. and Corma, A. (2003) Development of a low temperature light paraffin isomerization catalysts with improved resistance to water and sulphur by combinatorial methods. Appl. Catal. A Gen., 239, 35. 

Aromax (1) A catalytic process for converting light paraffins to benzene and toluene, using a zeolite catalyst. Developed by Chevron Research Technology Company. Installations were planned for Mississippi, Thailand, and Saudi Arabia. 

Total Isomerization Also called TIP. An integrated process which combines light paraffin isomerization, using a zeolite catalyst, with the IsoSiv process, which separates the unconverted normal paraffins so that they can be returned to the reactor. Developed by Union Carbide Corporation and now licensed by UOP. The first plant was operated in Japan in 1975 by 1992, more than 25 units had been licensed. 

The temperature coefficient of conductance is approximately 1-2 % per °C in aqueous 2> as well as nonaqueous solutions 27). This is due mainly to thetemper-ature coefficient of change in the solvent viscosity. Therefore temperature variations must be held well within 0.005 °C for precise data. In addition, the absolute temperature of the bath should be known to better than 0.01 °C by measurement with an accurate thermometer such as a calibrated platinum resistance thermometer. The thermostat bath medium should consist of a low dielectric constant material such as light paraffin oil. It has been shown 4) that errors of up to 0.5 % can be caused by use of water as a bath medium, probably because of capacitative leakage of current. 

The acidity probes discussed above are the most commonly used. However, the use of many different probes has been reported in the literature. This list includes nitriles, alkanes, amines, water, di-hydrogen, deuterium, isotopically labeled molecules, benzene, etc. Probe molecules can also be used to measure basicity on zeohtes. In this case, weakly acidic molecules such as CO2, pyrrole, acetic acid and halogenated light paraffins have been used. Space does not permit discussion of these in any detail, but information about these probes and their applications can be found in the following references [87, 127-130]. 

The dehydroaromatization of light alkane feeds (methane to butanes) into aromatics has come into prominence as a method of converting the unreactive light paraffins into useful chemical precursors. In many of the world s markets, light alkanes are very undesired off-gasses which can not be used other than as fuel. To accomplish this difficult transformation, catalysts typically are bifunctional, containing a dehydrogenating component such as Pt, Ga, Zn or Mo with an acidic zeolite. 

Metal-Zeolite Catalyzed Light Paraffin Isomerization... 

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