Assay Stream Blending Options
The pseudocomponents for petroleum assay streams with the option "Include Stream in Blending" are combined (blended) with the pseudocomponents for other included streams which use the same TBP Cutpoint set. Properties are then derived for these blended components, which are then used to represent every stream using that TBP Cutpoint set.
Petroleum assay streams with the option "Exclude Stream from Blending", are represented with the blend components generated from all included assays in the same TBP Cutpoint set. Note that there must be at least one included assay for the TBP Cutpoint set for the exclude option to be allowed.
Streams of similar composition may be accurately represented with the same pseudocomponents. Therefore the same TBP Cutpoint set may be selected for such streams to blend their components into a common set. For example, several light crude oils might be simulated with the same TBP Cutpoint set or several product streams from an FCC unit might be represented by the same TBP Cutpoint set. Additional details on the blending of pseudocomponent properties are given in Blending of Pseudocomponents.
Conversely, the same TBP Cutpoint set should not be used for dissimilar streams such as a virgin stock and a cracked stock since the blend components so produced would not represent either stock very accurately.
The exclude option is useful for providing an initial composition for a recycle stream. Assay data are estimated for the recycle stream and an initial composition is generated using the blend components for the included assay streams in the same TBP Cutpoint set. The estimated assay data has no effect on the blend component properties since the exclude option is used.
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