Recovery and re-use of waste energy in industrial facilities

A system comprising:

• a hydrocracking plant of a crude oil refining facility, the hydrocracking plant comprising feed furnaces, a first stage reaction section comprising a fixed-bed reactor vessel, a second reaction stage comprising another fixed-bed reactor vessel, and a fractionator column, wherein the hydrocracking plant is configured to perform at least one crude oil refining process and to flow a hydrocracking plant stream comprising at least one of a first stage reaction section feed stream to a first stage cold high pressure separator, a diesel product stream, a kerosene product stream, a second reaction stage feed stream to a second cold high pressure separator, a product stripper overheads stream, a kerosene pumparound stream;
• an oil refining plant of the crude oil refining facility, the oil refining plant being different from the hydrocracking plant, the oil refining plant comprising at least one of a sulfur recovery plant comprising an amine regenerator distillation column, a sour water stripper plant comprising a sour-water stripper distillation column, a gas separation plant comprising a de-ethanizer distillation column and a propane-butane splitter distillation column and through which a gas separation plant stream comprising at least one of C2 to C4 flows in the gas separation plant, a naphtha hydro-treating plant comprising a naphtha splitter distillation column, an amine regeneration plant separation section comprising an acid gas absorber vessel and an acid gas regenerator vessel, wherein an acid gas regenerator bottoms stream comprising a weak amine salt flows through the amine regeneration plant;
• a flow control system connected to the hydrocracking plant and the oil refining plant, the flow control system comprising one or more flow pumps, one or more flow pipes, and one or more valves, wherein the flow control system is configured to:
• flow the hydrocracking plant stream from the hydrocracking plant to a heat exchanger, and
• flow a stream from the oil refining plant to the heat exchanger;
• and
• the heat exchanger configured to transfer a portion of heat flowed through the hydrocracking plant stream to the stream from the oil refining plant.