Residual pressure and waste heat recovery power generation system and residual pressure and waste heat recovery method

The invention discloses a residual pressure and waste heat recovery power generation system and a residual pressure and waste heat recovery method, and belongs to the technical field of energy conservation and environmental protection. The residual pressure and waste heat recovery power generation system comprises a residual pressure power generation module and a power generation module, wherein the residual pressure power generation module comprises a first residual pressure expansion machine; the waste heat power generation module comprises a first evaporation device, a working medium expansion machine, a condensing device and a working medium pump; a fluid outlet of the first residual pressure expansion machine is connected with a fluid inlet of the first evaporation device, a working medium inlet of the first evaporation device is connected with an outlet of the working medium pump, a working medium outlet of the first evaporation device is connected with an inlet of the working medium expansion machine,