| abstract |
The invention is an improved method and apparatus for recovering waste heat from a low temperature process stream by means of a vaporizable heat sink liquid, characterized by an effective lowering of the boiling temperature of the heat sink liquid without need to reduce its boiling pressure. The heat sink liquid essentially comprises a mixture of two immiscible liquids that form a low boiling azeotrope. The heat sink liquid is brought into indirect heat exchange with the low temperature process stream for heat extraction. The invention involves simultaneous boiling of the two immiscible liquids to suppress the temperature of the heat sink liquid to below the low temperature of the process stream, whereby the heat sink liquid is able to recover heat from the process stream. In a preferred embodiment of the invention, the heat sink liquid comprises the reactants that are fed to a reactor, and the low temperature process stream is the reaction effluent from the reactor. |