True boiling range

True boiling point (True boiling range) the boiling point (boiling range) of a crude oil fraction or a crude oil product under standard conditions of temperature and pressure. 

This will not be true for mixtures with a wide boiling range). 

Table IV shows the properties of a typical C3 motor polymer of fullboiling range. It is somewhat heavier than the C3-C4 polymer and the octane rating is possibly a one-half number lower on the C3 polymer. The required equipment is the same as shown in Fig. 1. When C3 motor polymer is made, however, the debutanizer and rerun columns are not required. Figure 6 shows a true-boiling-point curve of typical C3 motor polymer.

When complex multicomponent mixtures are distilled, particularly those associated with oil refining, it is difficult to characterize them in terms of their components. Instead, they are characterized in terms of their boiling range, which gives some indication of the quantities of the components present. The true boiling point distillation (TBP) is probably the most useful, in which the percent distilled is recorded as a function of the boiling temperature of the mixture. For the TPB distillation, a 5 1 reflux ratio is often used with 15 theoretical stages in a laboratory characterization column (see Section III). 

The Project Lignite SRL contains a moderate percentage of distillable material, and this distillate resembles the process solvent. The mass spectrum of this distillate is essentially a fingerprint of the solvent at mass 178 and above. These data would appear to indicate that some material in the boiling range of the solvent was not separated completely from the SRL. Appearance of distillable compounds in the SRL also might reflect a true difference in product composition, i.e., solvent... 

Symbol Name True boiling-point range (°F) Description of uses... 

A full assay involving the preparation of a true boiling point curve and the analysis of fractions and product blends throughout the full range of the crude oil. 

One of the most important physical parameters dehning these products is their boiling range distribution (ASTM D-86, ASTM D-1078, ASTM D-2887, ASTM D-2892, IP 123). However, this method is a low-efficiency, one-theoretical plate distillation, and, although it has been adequate for product specihcation purposes, true boiling point (TBP) data are also required (ASTM D-2887, ASTM D-2892). 

As is true with all naturally occurring feed stocks, the composition or boiling range of crude oil varies greatly from production field to production field. This variability results in a very significant dynamic control problem in a refinery that feeds crude oil from a variety of sources, which is often the case. 

For more rigorous work with boiling range materials, the pseudocomponent method should be used. The true boiling point curve for the mixture (feed or product) is broken up into a series of steps as shown in Fig. 5.5-8, each step representing a pseudocomponent with boiling point as indicated. Next, the material... 

Those checking the reference from where this technique was developed will find mention that it should only be applied to pure hydrocarbons and narrow-boiling range petroleum fractions. However this restriction applies primarily to the conversion between the true normal boiling point (Ti,) and the boiling point corrected to a Watson K of 12 (T ). The procedure for calculating PCT does not involve this conversion and experience shows that the resulting formula works well. 

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