Visbreaking Back

Action Decompose
Method Thermal
Purpose Reduce viscosity or pour point
Feedstock Atmospheric tower residue


Product(s) goes to

Gas plant
Catalytic cracking

Visbreaking is a mild form of thermal cracking in which only about 15% of the feedstock is converted to lighter products. The main job of a visbreaker is to significantly reduce the viscosity of feedstock and the pour point of waxy residue in such a way that it meets the required specifications of the refinery bottom product.

The distillation residue is mixed with a stream of valuable gas oil. The mixture is mildly cracked at a high temperature to produce a lighter distillate. The thermally cracked residue (tar) accumulates in the bottom.

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 Visbreaking

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 visbreaking. 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). For heavy byproducts, the conversion from density to API gravity is implemented according to ASTM D1250 (product group D: lubricants).