Abstract: In view of the requirements of online blending process for marine residue fuel oil，a residue dilution model and a marine fuel oil online management system were developed with a new efficient static mixer. A residual fuel oil online blending process was developed. An online mixing test device with capacity of 240 L/h was established. The operation test showed that the equipment was running smoothly，which can realize the whole process, including blending scheme generation，continuous production automatic control，product performance real-time feedback. All national standard marine residue fuel oil can be produced by this process and the product has a good stability.

Key words: residue fuel oil, viscosity model, continuous online blending process, small test device