Blending stock

Typical compositions of gasolines according to blending stock origin. Before lead addition. 

Recoveries of 90—95% ethane have been achieved usiag the expander processes. The Hquid product from the demethanizer may contain 50 Hquid vol % ethane and usually is deHvered by a pipeline to a central fractionation faciHty for separation iato LPG products, chemical feedstocks, and gasoline-blending stocks. 

The principal use of the alkylation process is the production of high octane aviation and motor gasoline blending stocks by the chemical addition of C2, C3, C4, or C5 olefins or mixtures of these olefins to an iso-paraffin, usually isobutane. Alkylation of benzene with olefins to produce styrene, cumene, and detergent alkylate are petrochemical processes. The alkylation reaction can be promoted by concentrated sulfuric acid, hydrofluoric acid, aluminum chloride, or boron fluoride at low temperatures. Thermal alkylation is possible at high temperatures and very high pressures. 

Figure 1 shows a simplified flow plan for a typical hydroskimming refinery. The atmospheric pipestill performs the initial distillation of crude oil into gas, naphtha, distillates, and residuum. The naphtha may be separated into gasoline blending stock, solvents, and Powerformer feed. The distillates include kerosene, jet fuel, heating oil and diesel oil. The residuum is blended for use as bunker fuel oil. 

Visbreaking is a mild thermal cracking process that reduces the viscosity of heavy fuel oils and reduces the amount of low-viscosity blending stocks that must be added to the heavy residuals to meet viscosity specifications of the specific heavy fuel oil. The amount of heavy fuel oil production by a refinery is reduced by 20—30 percent if a visbreaker is used. The refinery profitability is improved with visbreaker operation, because heavy fuel oils are low value products. 

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,... 

After bauxite treatment the product was fractionated to produce C3-C4 and naphtha (C5-204°C) fractions. The C3-C4 olefin-rich gas was oligomerized over a solid phosphoric acid (SPA) catalyst to produce an unhydrogenated polymer gasoline with a research octane number (RON) of 95 and MON of 82.21 The bauxite-treated FT motor gasoline (RON of 87, MON of 76) was mixed with the polymer gasoline and some natural gas condensates (and crude-oil-derived naphtha) to produce the final motor gasoline product. In this respect it is noteworthy that the Fe-HTFT-derived material was the high-octane-blend stock. 

In addition to the Fischer-Tropsch-derived material, coal-derived liquids were also recovered from low-temperature coal gasification (not shown in Figures 18.3 and 18.4). These products were processed separately to produce chemicals, such as phenols, cresols, and ammonia, as well as an aromatic motor gasoline blending stock.34 The latter was mixed with the Fischer-Tropsch-derived motor gasoline. 

The refinery design included the co-refining of natural gas liquids, not only as a blending stock, but also as an integral part of the feed to the refinery. This created synergy and allowed refining pathways that would otherwise be less efficient. 

Sulfuric acid alkylation an alkylation process in which olefins (C3, C4, and C5) combine with isobutane in the presence of a catalyst (sulfuric acid) to form branched-chain hydrocarbons used especially in gasoline blending stock. 

The C4 s can be recovered in numerous ways to malce petrochemical feeds. Sometimes everything but the butadiene ends up in an alkylation plant that makes gasoline blend stock. 

GNB by the procedures given above. Simllarily leaflike, seed, stem and bark trash materials were removed from llnters, gin motes, blended stock and batting being processed by a garnetter in West Texas in 1977. Separated trash materials, fiber minus gross trash, and unsorted llnters, gin motes, blended stock and batting were analyzed for entrained GNB levels. Finally, all botanical trash... 

Linters, gin motes, blended stock and batting Lint and linters minus trash Gross trash... 

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