Utilizing waste heat for thermal desalination

A method for desalination of salt water, the method comprising:

• producing a hot flue gas in a furnace of a crude oil refinery or hydrocarbon refinery, the furnace comprising:
• a radiant section;
• a convention section located above the radiant section;
• a flue gas stack located above the convection section;
• feeding a water stream to a heating coil located in a path of the hot flue gas in the flue gas stack;
• heating the water stream using the hot flue gas to convert a portion of the water to a steam stream in the heating coil;
• feeding the steam stream directly to a flash drum;
• separating, in the flash drum, the steam stream into a dry steam and a residual water stream;
• recycling the residual water stream to the heating coil;
• and
• feeding dry steam to a multi effect desalination plant to produce a desalinated water.