Straight-run

There are little or no olefins in crude oil or straight run (direct from crude distillation) products but they are found in refining products, particularly in the fractions coming from conversion of heavy fractions whether or not these processes are thermal or catalytic. The first few compounds of this family are very important raw materials for the petrochemical Industry e.g., ethylene, propylene, and butenes. 

In straight-run petroleum products which do not usually contain olefins, four types of hydrogen can be easily differentiated as seen in the spectrum in Figure 3.10 ... 

The resolution of capillary columns enables the separation of all principal components of a straight-run gasoline. The most frequently used stationary phases are silicone-based, giving an order of hydrocarbon elution times close to the order of increasing boiling point. 

Figure 5.11 Cetane profile of a straight run diesel fuel. ...

The properties of straight run diesel fuels depend on both nature of the crude oil and selected distillation range. Thus the paraffinic crudes give cuts of satisfactory cetane number but poorer cold characteristics the opposite will be observed with naphthenic or aromatic crudes. The increasing demand for diesel fuel could lead the refiner to increase the distillation end point, but that will result in a deterioration of the cloud point. It is generally accepted that a weight gain in yield of 0.5% could increase the cloud point by 1°C. The compromise between quantity and quality is particularly difficult to reconcile. 

Straight run diesei fuels have a high paraffin content, which is desirable, incidentally, for obtaining high cetane numbers. The higher the distillation end point, the higher is the heavy paraffin content (with a carbon number greater than C24). 

Table 10.21 gives a typical example of hydrotreating a straight run (SR) gas oil. 

Straight-run asphalts Straight run naphthas Strain gauges Strainmaster S. strain NRRL 15496 Stratosphere Stratospheric ozone... 

Straight Run Asphalt. In cmde-oil refining, the crude oil at 340—400°C is injected into a fractionating column (5,6,19,20). The lighter fractions are separated as overhead products and the residuum is straight-reduced asphalt. 

Table 2. Properties of Straight Run Naphthas from Various Crude Oils...

In addition to straight run naphthas, 70—190°C cuts obtained by distillation from streams produced by cracking high boiling petroleum fractions can also be used as feed to reformers. Naphthas produced by hydrocracking are particularly suitable. 

Rotameters require no straight runs of pipe before or after the point of installation. Pressure losses are substantially constant over the whole flow range. In experimental work, for greatest precision, a rotameter should be cahbrated with the flmd which is to be metered. However, most modern rotameters are precision-made so that their performance closely corresponds to a master cahbration plot for the type in question. Such a plot is supphed with the meter upon purchase. 

Poor suction piping layout, too many elbows in too many planes, a tee branch almost directly feeding the suction of the other pump, or not enough straight run before the suction flange of the pump. 

Seller shall state in the proposal the reeommended and minimum straight run of piping for the expander inlet and exhaust. 

Gullerlly valve in straight run entering compressor Inlet... 

Euel oil, residues-straight-run gas oils, high sulphur Euel oil, residual... 

Combining both expressions gives a simple relation for estimating the frictional pressure drop in straight run pipe. 

The flow of fluid leaving a choke is in the form of a high-velocity jet. For this reason it is desirable to have a straight run of pipe of at least ten pipe diameters downstream of any choke prior to a change in direction, so that the jet does not impinge on the side of the pipe. 

Naphtha is a generic term normally used in the petroleum refining industry for the overhead liquid fraction obtained from atmospheric distillation units. The approximate boiling range of light straight-run naphtha (LSR) is 35-90°C, while it is about 80-200°C for heavy straight-run naphtha (HSR). ... 

Typical analyses of two straight-run naphtha fractions from two crude types... 

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