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Alkylation Back

Action Combining
Method Catalytic
Purpose Unify olefins and iso-paraffins
Feedstock Iso-butane, olefins
Product(s)

High octane gasoline, alkylate

Product(s) goes to

Blending

After the invention of catalytic cracking, engineers started to think what to do with all the light ends created at the process. The objective was to maximize the volume of produced gasoline, but butylene and propylene were too volatile to stay dissolved in the gasoline blends. So alkylation was invented to use such small molecules in order to build up larger ones.

Alkylation combines olefins of low molecular weight with iso-paraffins in the presence of a catalyst, either sulfuric acid or hydrofluoric acid (or aluminum chloride), to create a high-octane, branched chain hydrocarbon called alkylate. Alkylate is comprised of branched chain paraffins, such as iso-octane, and has exceptional anti-knock qualities. The alkylate is then separated and fractionated. The reaction temperatures are kept relatively low by refrigeration.

Sulfuric acid units are more popular than hydrofluoric acid units, because hydrofluoric acid is extremely dangerous to produce, ship, store and use.  Because of this danger, regulation, and its rarity, hydrofluoric acid  is more expensive. Sulfuric units work better for butylene alkylation. Hydrofluoric units work better for propylene alkylation.

DMA Generation M

The DMA Generation M density meters measure the density and concentration of liquids. They provide preset measuring methods and integrated conversion tables for many applications. The FillingCheckTM function automatically detects filling errors and gas bubbles in the sample to avoid measuring errors.

Accuracy, density:
0.0001 g/cm³ (DMA 4100 M)
0.00005 g/cm³ (DMA 4500 M)
0.000005 g/cm³ (DMA 5000 M)

Repeatability s.d., density:
0.00005 g/cm³ (DMA 4100 M)
0.00001 g/cm³ (DMA 4500 M)
0.000001 g/cm³ (DMA 5000 M)

Benefits of DMA Generation M at Alkylation

Product:

DMA 4100 M, DMA 4500 M and DMA 5000 M can directly measure API gravity (calculated from true density), a necessary parameter for quality control of process samples coming from alkylation. The conversion from density to API gravity is implemented according to ASTM D1250 (product group B: refined products).  A sample changer is used for high sample throughput (Xsample 452) and allows for highly repeatable results (Xsample 352/452).

Catalyst:

Sulfuric acid and hydrofluoric acid are important catalysts for the process of alkylation. To ensure stable process control, the quality of required catalysts has to be monitored. DMA 4100 M, DMA 4500 M and DMA 5000 M are suitable instruments for measuring the liquid density of acids; concentration is directly reported in % w/w.