Method for producing ultralow-sulfur marine fuel oil through low-pressure hydrogenation of heavy inferior residual oil

The invention relates to a method for producing ultralow-sulfur marine fuel oil by low-pressure hydrogenation of heavy inferior residual oil, which comprises the following steps: 1) mixing the heavy inferior residual oil, a catalyst and hydrogen, feeding into a multiphase flow hydrogenation reactor, and separating the reaction product by a primary separator to obtain light distillate oil and heavy distillate oil; 2) separating the heavy distillate oil by a secondary separator to obtain a light wax oil fraction, a heavy wax oil fraction and solid-containing asphalt; 3) mixing the light wax oil fraction and the light distillate oil, feeding the mixture into a fixed bed reactor, and obtaining naphtha, diesel oil and a first marine fuel oil blending component through a fractionating tower; 4) taking a part of the heavy wax oil fraction as circulating solvent oil and a part of the heavy wax oil fraction as a second marine fuel oil blending component; and 5) blending the first and second marine fuel oils to obtain