Dry ice pretreatment device based on PID control

The utility model discloses a dry ice pretreatment device based on PID (Proportion Integration Differentiation) control, and relates to the field of dry ice production, a liquid carbon dioxide input pipeline is connected to a buffer tank after passing through a precooler, and the buffer tank is connected to the input end of dry ice production equipment through a liquid carbon dioxide output pipeline; a first PID (Proportion Integration Differentiation) controller is arranged at an input valve of the liquid carbon dioxide input pipeline; the first PID controller controls the opening degree of the input valve so that the liquid level in the buffer tank can be kept within a preset range. The top end of the buffer tank communicates with a gas output pipeline, a second PID controller is arranged at a gas outlet valve of the gas output pipeline, and the second PID controller controls opening and closing (opening degree) of the gas outlet valve so that the inner top pressure in the buffer tank can be kept within a p