Gasoline olefin content

The PONA results at constant conversion (72 vol%) in the series from EKZ4 to BETA 500 show gasoline olefin content increased from 8.6 percent to 16.4 percent, paraffin content decreased from 54.7 percent to 46.8 percent, and naphthene and aromatics contents remained constant. Research octane increased 4.2 numbers while motor octane increased 1.2 numbers. The aromatics content of the LCO as measured by the aniline point decreased with the aniline point increasing from 42 to 62. LCO yield increased from 16.0 volume percent to 18.0 volume percent, while the coke yield decreased dramatically from 4.2 percent to 2.4 percent. 

Amylenes. Amylenes (C monoolefins) produce alkylates with a research octane in the range of 90—93. In the past, amylenes have not been used widely as an industrial alkylation charge, although in specific instances, alkylation with amylenes has been practiced (23). In the future, alkylation with amylenes will become more important as limits are placed on the vapor pressure and light olefin content of gasolines. 

In 1990, U.S. gasoline contained about 10 vol% olefins, the majority of which emanate from FCC gasoUne. FCC gasoline has 25 vol% to 35 vol% olefins. Of these olefins, Cg-C olefins account for about 85% of the total pool. For non-RFG gasoline, as with sulfur, the regulation allows the maximum olefin content to be 125% of the 1990 baseline values. 

Octgain A hydrofinishing process which reduces the sulfur and olefin content of gasoline without reducing its octane number. A zeolite catalyst is used. Developed by Mobil in 1994. Chem. Eng. (N.Y.), 1994,101(7), 25. 

Aromatics are typically included in gasolines to increase octane number. However, high aromatic content increases engine-out hydrocarbons and NOx emissions.16 Moreover, aromatics are the main precursors of exhaust benzene, a known carcinogenic, via dealkylation of substituted aromatics.17 Therefore, reduction of total aromatic content, together with olefin content, is an important part of California phase III reformulated gasoline specifications,18 with respect to the current allowed concentrations of benzene and total aromatics of 0.8 and 25 percent of volume, respectively. 

The effect of hydrotreating on the bromine number (olefinic content) of the catalytic cracker products is shown in Figures 11 and 12. The bromine numbers for gasoline and LCO fractions were measured directly using ASTM procedure D 1159. For the HCO, the bromine number could not be measured because of procedural problems. For the low severity cracking case. Figure 11, the... 

The specifically formulated CGP-1 catalyst plays a vital role in the MIP-CGP process. Unique catalyst design, such as metal promoted MFl zeolite, phosphorus modified Y zeolite, and a novel matrix with excellent capability to accommodate coke [12] were involved to ensure the primary cracking and secondary reactions to proceed within a defined path. The commercial trial results of the MIP-CGP process in SINOPEC Jiujiang Company showed that, in combination with CGP-1 catalyst, the propylene yield was 8.96 wt%, which increased by more than 2.6% as compared with FCC process. The light ends yield and slurry yield are basically equal. The olefin content of the gasoline produced by MIP-CGP process was 15.0 v%, which was 26.1% lower than that of FCC gasoline. The sulfur content of gasoline was decreased from 400 to 270 pg/g. 

With the application of DMMC-1 catalyst, the propylene yield is 17.80 wt%, which is higher by 2.43% as compared with the MMC-2 catalyst. The light ends yield increases by 0.64%, and the coke yield decreases by 0.56 wt%. Furthermore, the olefin content of gasoline decreases by 4.5 v%. Thus the worldwide leading position of DCC in propylene production from catalytic cracking has been advanced further. 

Cracked gasoline FCC gasoline Composed of paraffinic, olefinic, and aromatic compounds branched compounds are present in a relatively high amount typically has a higher RON than MON high-olefin-content FCC gasoline can lead to gum formation and fuel color degradation. 

This is the breakdown of the percentage of paraffins, olefins, naphthenes and aromatics in gasoline. Fuel olefin content is closely monitored. High-olefin-content gasoline is unstable and can lead to various fuel problems such as deposit formation and color degradation. 

Crude oil typically contains little to no olefinic compounds. Through refining and processing, however, olefins are produced and become a part of various crude oil fractions. Olefins can be found in thermally cracked and catalytically cracked gasoline fractions as well as in FCC cycle oils and coker gas oils. For this reason, it is not unusual for finished gasoline and distillate blends to contain a high-olefin-content stream. 

High olefin content possibly due to addition of FCC gasoline to blend... 

Effect of Pressure. Pressure is an independent variable. An increase in pressure favors the production of coke. It also favors production of gasolines of low olefin content, which is necessary in the production of aviation gasoline. 

As far back as 1938, it had been proved commercially that repassing or treating the primary aviation gasoline over the cracking catalyst resulted in a product of lower olefin content, higher aromatic content, and improved response to tetraethyllead, decreasing sharply the proportion of alkylate necessary in the blend. 

The olefin content of the gasoline pool has decreased from 19% on a leaded basis to only 9% on a lead free basis. Aromatics, however, have increased from 21 to 42%, respectively, and are as high as 51% in the premium gasoline. 

Up to this point only the elimination of lead anti-knock compounds has been considered. Legislation on the volatility, olefin content, or aromatic content of gasoline could also have a significant effect on the future of alkylation and isomerization. It is impossible to predict what legislation, if any, will be passed to regulate the properties of gasoline, but the directional effects of such legislation can be indicated ... 

Olefin Reductions—Alkylation capacity would increase with any reduction in olefin content because it would provide a way to use the C4 and some C5 olefins in gasoline. New isomerization capacity would be needed if substantial quantities of C5 and C6 olefins had to be removed. The C5/C6 olefins would have to be hydrogenated and isomerized to make up part of the octane loss. 

Today, NIR analyzers are being used in the refineries to determine many different properties in addition to the octane numbers of gasoline. One refinery is measuring 25 properties of their gasoline every 45 seconds. Once the spectrum has been acquired, it just takes some calculations on the attached computer to determine additional analytical properties, such as boiling points, olefin content of the gasoline, aromatic content, methyl... 

---