Fractional fuel oil includes diesel oil and 4# fuel oil. The residual fuel mainly includes 120CTS, 180CTS and 380CTS.
Generally, ships have two sets of power systems, namely, main engine and auxiliary engine. Generally, the fuel of the main engine is residual fuel oil, and the fuel of the auxiliary engine is distillate fuel oil. According to maritime conventions, port requirements and environmental protection laws and regulations of various countries and regions, ships can burn residual fuel oil within a certain distance from the coastline, but they must burn distillate fuel oil when entering ports and some special areas. At the same time, ships also burn distillate fuel oil to ensure safety when sailing under some fine operations and harsh conditions.
In addition, it should be noted that by ship, I mean large-tonnage oil tankers, groceries, loading and packaging ships, etc. Generally speaking, small tonnage ships use different fuels because of different engines. For example, fishing boats generally only use 4# fuel oil.