High-back-pressure unit heat exchange cooling device and heat exchange method

The invention relates to a high-back-pressure unit heat exchange cooling device and a heat exchange method. The high-back-pressure unit heat exchange cooling device comprises a condenser for heating return water of a heat supply network, a first-stage heat exchanger for cooling dead steam of a steam turbine, and a second-stage heat exchanger for cooling the dead steam of the steam turbine by using water of a raw water mechanical acceleration clarification tank. The dead steam flowing out of the steam turbine in a high-back-pressure unit is fully utilized to exchange heat between the return water of the heat supply network and raw water, meanwhile, the purpose of reducing the temperature of condensed water flowing into condensed water fine treatment equipment is achieved, the temperature of a mechanical acceleration clarification tank is increased, and the turbidity of water in the mechanical acceleration clarification tank is reduced; the phenomenon that anion resin is dissolved and enters a water vapor syste