Bureau of Mines Correlation BMCI

The distribution of compounds produced by this operation is quite different from that obtained from naphtha. The main reason for this is the pronounced aromaticity" of gas oils, which affects the maximum ethylene yield. Moreover, this parameter may substantially from one gas oil to another, and in comparable ojserating conditions this partly explains the wide differences observed in the distribution of the hydrocarbons formed. The Stone and Webster Company established a correlation between the BMCI (Bureau of Mines Correlation Index) for gas oils and the maximum ethylene yield. The BMCL created in 1940, represents an aromaticity index" deOned by the foDowing equation ... 

Aromaticity is the most important property of a carbon black feedstock. It is generally measured by the Bureau of Mines Correlation Index (BMCI) and is an indication of the carbon-to-hydrogen ratio. The sulfur content is limited to reduce corrosion, loss of yield, and sulfur in the product. It may be limited in certain locations for environmental reasons. The boiling range must be low enough so that it will be completely volatilized under furnace time—temperature conditions. Alkane insolubles or asphaltenes must be kept below critical levels in order to maintain product quaUty. Excessive asphaltene content results in a loss of reinforcement and poor treadwear in tire appHcations. 

When simple Hquids like naphtha are cracked, it may be possible to determine the feed components by gas chromatography combined with mass spectrometry (gc/ms) (30). However, when gas oil is cracked, complete analysis of the feed may not be possible. Therefore, some simple definitions are used to characterize the feed. When available, paraffins, olefins, naphthenes, and aromatics (PONA) content serves as a key property. When PONA is not available, the Bureau of Mines Correlation Index (BMCI) is used. Other properties like specific gravity, ASTM distillation, viscosity, refractive index. Conradson Carbon, and Bromine Number are also used to characterize the feed. In recent years even nuclear magnetic resonance spectroscopy has been... 

Selling the DO as CBFS yields a better return than selling it as cutter stock. To meet the CBFS specification, DO must have a minimum Bureau of Mines Correlation Index (BMCI) of 120 and a low ash content (Table 6-2). Aromaticity and ash content are the two most important properties of CBFS. 

The selection of steam cracker feedstock is mainly driven by market demand as different feedstock qualities produce different olefins yields. One of the commonly used feed quality assessment methods in practice is the Bureau of Mines Correlation Index (BMCI) (Gonzalo et al., 2004). This index is a function of average boiling point and specific gravity of a particular feedstock. The steam cracker feed quality improves with a decrease in the BMCI value. For instance, vacuum gas oil (VGO) has a high value of BMCI and, therefore, is not an attractive steam cracker feed. The commonly used feedstocks in industry are naphtha and gas oil. 

For three narrow fractions with midcut boiling points of 235°-325°C, the Bureau of Mines Correlation Index (BMCI) is 42-45, respectively. 

For some liquid feedstocks such as naphthas, the componential composition is often obtained by gas chromatography (GC) and/or mass spectrometry (MS). For gas oils or heavier feedstocks, it is impossible to obtain the desired analysis. Paraffins, olefins, naphthenes, aromatics (PONA) grouping is sometimes used as a means of feed characterization. For gas oils. Bureau of Mines Correlation Index (BMCI) has been used as a parameter for feed characterization. Since the 1980s, nuclear magnetic resonance (NMR) spectroscopy has been used to characterize heavy feedstocks. 

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