Distillate sweetening, treating & blending Back

Action Treatment
Method Catalytic Adsorption Thermal
Purpose Remove H2S, convert mercaptan
Feedstock Untreated distillate (gasoline, middle distillate, kerosene, jet fuel, alkylation feedstock, liquid hydrocarbons)

Final petroleum products

Product(s) goes to


Sweetening (mercaptan removal)

Sweetening improves color, odor, oxidation stability, carbon residue and other properties in gasoline. Mercaptans can be removed by water-soluble chemicals. Caustic treatment employs sodium or potassium hydroxide to improve odor and color by removing organic acids and sulfur compounds (mercaptans, H2S). By mixing caustic solution with various solubility promoters, up to 99 % of mercaptans as well as oxygen and nitrogen compounds can be dissolved from petroleum fractions. Amine compounds or fixed-bed catalysts also may be used for sweetening.


Many refinery products require treating in order to be used in gasoline and other blends. Distillates may contain trace amounts of organic compounds and aromatics, sulfur, nitrogen and oxygen, dissolved metals and inorganic salts. Such undesirable compounds can be removed by treating, either at an intermediate stage or just before sending finished products to blending and storage. Treating materials include acids, solvents, alkalis as well as oxidizing and adsorption agents. Acid treatments are used to prevent corrosion, avoid catalyst contamination and to improve product stability.

Drying is accomplished by the use of water absorption or adsorption agents to remove water from the products. Some processes simultaneously dry and sweeten by adsorption on molecular sieves.


Blending mixes proportional amounts of different types of liquid fractions to produce finished products with desired specifications. Products can be blended either in-line or batchwise.

Additives are often added to final products during or after blending to impart specific properties in final products. These additives include octane enhancers, anti-oxidants, metal deactivators, anti-knock agents, rust inhibitors, gum inhibitors, foam inhibitors, carburetor cleaners, detergents (for cleaning injectors), color dyes, diesel odorizers, distillate anti-static agents, gasoline oxidizers and others.

DMA 35 Ex Petrol

The DMA 35 portable density meter measures the density, SG and °API of samples on-site within seconds. The intrinsically safe instrument (ATEX-marking II 2 G Ex ib IIC T4) has a special housing, resistant to petroleum samples. It is therefore perfectly suitable for measuring petroleum samples in hazardous areas. The integrated RFID interface enables quick sample identification (e.g. tank number) before measurement. Measured results can be stored and printed or exported to a PC wirelessly via IrDA later on. The instrument fully complies with the ASTM D7777 standard.

0.001 g/cm3

Repeatability s. d.:
0.0005 g/cm3

Measuring range:
0 g/cm3 to 3 g/cm3

Minimum sample volume:
2 mL

Benefits of DMA 35 Ex Petrol at Distillate sweetening, treating & blending

The DMA 35 Ex Petrol portable density meter measures the API gravity, API SG or API density (calculated from true density) of samples (product group B: refined samples) directly at the sampling location. Especially during blending a quick density check is perfectly suitable for judging the status of blending based on the noticeable stratification of density layers within a tank. It automatically displays the measured value, already compensated to your reference temperature of choice.