Gasoline end point

The gasoline end point should not exceed a given value, currently established for Europe at 215°C. In fact the presence of too-heavy fractions leads to incomplete combustion and to a number of accompanying problems ... 

Depending on seasonal demands, the gasoline end point can range from 38()°F to 450°F (193°C to 232°C). Undercutting of gasoline increases the LCO product and can appear as low conversion. Therefore, it is necessary to distinguish between the apparent and true conversion. The apparent conversion is calculated before the gasoline end point adjustment is made, and the true conversion is calculated after the adjustment. 

Increasing gasoline end point by reducing the main column top pumparound rate... 

Gasoline End Point. The effect of gasoline end point on its octane number depends on the feedstock quality and severity of the operation. At low severity, lowering the end point of a paraffinic feedstock may not impact the octane number however, reducing gasoline end point produced from a naphthenic or an aromatic feedstock will lower the octane. 

A refiner has several options to increase LCO yield. Since it is often desirable to maintain a maximum cracking severity while maximizing light cycle oil yield, the simplest way to increase LCO yield is to reduce the gasoline end point. Gasoline end point is usually reduced... 

Verify the gasoline end point, vapor pressure, and LCO distillation to ensure minimum undercutting of LCO. 

Check for changes in the gasoline end point and vapor pressure. 

FCC feed hydrotreating Gasoline end point reduction FCC gasoline hydrotreating Catalyst additives Bio-catalytic desulfurization... 

With the foregoing explanation it is now possible to study a little more closely the composition of the various streams of natural gas liquids which make up 10% of the total petroleum supply of the United States. Of the total 207,500,000 barrels produced in 1950, approximately 35,000,000 barrels were propane about 53,500,000 barrels, butanes and about 107,500,000 barrels, isopentane and heavier, up to the gasoline end point and perhaps 11,500,000 barrels represented products heavier than gasoline (Table V). About 124,000,000 of the total production moved to market through oil refineries. This represents less than 60% of the total. The natural gas liquids taken by refiners are classified ... 

Roughly speaking, this use includes ail of the pentanes and heavier hydrocarbons distilling up to gasoline end point plus some of the butanes, totaling about 70% of the recent annual production of natural gas liquids. 

Changing the gasoline end point does not significantly affect octane but does have a large effect on yield. 

Outside of their very high resistance to auto-ignition, the aviation gasolines are characterized by the following specifications vapor pressure between 385 and 490 mbar at 37.8°C, a distillation range (end point less than 170°C), freezing point (-60°C) and sulfur content of less than 500 ppm. 

In order to draw the property-yield curves for gasolines , it suffices to choose the initial point, which coilild be or 20°C, the end point being variable and situated between the end point of the heaviest gasoline cut which can be produced (200-220°C) and about 350°C. 

As discussed earlier in this chapter, gasoline and LCO yields are generally corrected to a constant boiling range basis. The most commonly used bases are 430°F TBP gasoline and 640°F TBP LCO end points. Since TBP distillations are not routinely performed, they are often estimated from the D-86 distillation data. The adjustments to the end points involve the following ... 

Alkylation, where the olefins are reacted with isobutane to make a very desirable gasoline blending stock. Alkylate is an attractive blending component because it has no aromatics or sulfur, low vapor pressure, low end point, and high research and motor octane ratings,... 

Tailpipe emissions of HC and CO are affected by the levels of heavy aromatics in gasoline. Like sulfur, the heavy aromatics are in the back end of the boiling range (Figure 10-4). As with sulfur, reduction of end point directly controls the concentration of heavy aromatics in finished gasoline. 

Figure 10-4. Aromatic content of gasoline versus its end point.

The naphtha processed by a gasoline Molex unit typically has a Enger distillation (D86) with an initial boiling point (IBP) of 26°C and end point (EP) of 82°C. Table 8.3 lists the typical components found in naphtha with their corresponding calculated research octane numbers (RON) and shows why nCs and nCc are undesirable in a gasoline pool due to their low RON value [8]. 

Tar is defined as the part of the polymer product boiling above 400° F. end point gasoline, and the weight % may be determined from Figure 8 as a function of total polymer... 

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