Visbreaking bitumen

Donor Refined Bitumen (Golf) Hydrogen Donor Diluent Visbreaking Exxon ... 

Vacuum residue for bitumen production and feed for visbreaker... 

If bitumens are regared as model substances for heavy residues, then their Arrhenius coefficients can serve as the basis for the calculation of the kinetics of pyrolysis reactions in thermal conversion processes (thermal cracking, visbreaking, hydrotreating etc.). Integration of the peak areas gives a value for the energy required for pyrolysis reactions. 

The blown bitumens do not exhibit peaks in the evaporation range when the system pressure is inereased to 10 bar, except for the dispersion medium of the bitumens 85/40 and 85/25, which demonstrate only an evaporation loss. The Arrhenius coefficients of the blown bitumen showed greater differences than those of the distillation bitumens. In the plot of half life time, versus the inverse Kelvin temperature, the distillation bitumens and their colloid components follow almost parallel lines, whereas the graphs for the blown bitumens and their colloid components diverge. The plot of versus 1 000/T shows the residence time required to achieve a conversion of fifty percent, at a preset reaction temperature, or which temperature is required to achieve a preset conversion at a preset residence time. This information is valuable in thermal processing, for example in selection of the crack severity of the visbreaking process. 

This is a complex refinery, with a light crude capacity of 8 Mt y and a heavy crude capacity of 1.2 million. It includes an FCC, a catalytic reformer, a visbreaker, a gas oil hydrodesulfurization unit, a naphthenic bitumen unit and a paraffinic oil unit. It is supplied by the water table for boiler make up (3.3-10 m y and by Seine river water for industrial and cooling water. Cooling is partly once-through and partly open recirculating. 

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