Recovery and re-use of waste energy in industrial facilities

A method implemented in a crude oil refining facility, the method comprising:

• in a crude oil refining facility comprising a plurality of oil refining plants, each oil refining plant configured to perform at least one oil refining process, each oil refining plant comprising a plurality of interconnected oil refining sub-systems, wherein a plurality of streams at respective temperatures flow between the plurality of oil refining sub-systems:
• flowing a gas separation plant stream comprising at least one of C2 to C4, an acid gas regenerator bottoms stream comprising a weak amine salt and a first aromatics complex stream comprising at least one of benzene, toluene or xylene from a gas separation plant, an amine regeneration plant and an aromatics complex, respectively, of the plurality of oil refining plants to one or more heat exchangers;
• flowing a second aromatics complex stream comprising at least one of benzene, toluene or xylene, the second aromatics complex stream being different from the first aromatics complex stream, from the aromatics complex of the plurality of oil refining plants to the one or more heat exchangers, wherein the one or more heat exchangers transfer heat from the second aromatics complex stream to at least one of the gas separation plant stream, the acid gas regenerator bottoms stream and the first aromatics complex stream;
• and
• utilizing the heated gas separation plant stream, the heated acid gas regenerator bottoms stream and the heated first aromatics complex stream in an oil refining process at the gas separation plant, amine regeneration plant and the aromatics complex.