Carbon dioxide trapping system

The invention discloses a carbon dioxide trapping system which comprises an absorption tower, a desorption tower and a Rankine cycle system, the desorption tower is provided with a separated gas discharge pipeline, and a rich solution conveying pipeline and a barren solution conveying pipeline are arranged between the absorption tower and the desorption tower. The Rankine cycle system comprises a turbine generator set, a condenser, a working medium conveying pump, a heat recovery heat exchanger and an evaporator, the turbine generator set, the condenser, the working medium conveying pump, the heat recovery heat exchanger and the evaporator are connected through a working medium conveying pipeline to form a thermodynamic cycle, and the condenser is arranged on a rich liquid conveying pipeline. The heat recovery heat exchanger is arranged on the separated gas discharging pipeline, and the evaporator is arranged on the barren solution conveying pipeline. According to the scheme, a Rankine cycle system working me