Control equipment, method and device for ternary gas phase composition in olefin gas phase copolymerization

The invention discloses equipment, a method and a device for controlling ternary gas phase composition in olefin gas phase copolymerization. The equipment comprises a flow controller, a temperature measuring module, a pressure measuring module, a tail gas line and a tail gas line emptying branch, wherein the input end of the flow controller inputs various gases, and the output end of the flow controller is connected with a gas inlet of a gas-phase polymerization reactor through a feeding line; the temperature measuring module and the pressure measuring module are arranged on the gas-phase polymerization reactor; the input end of the tail gas line is connected with a dilute-phase region of the gas-phase polymerization reactor; the Coriolis flow meter, the thermal flow meter and the differential pressure flow meter are sequentially arranged on the tail gas line, and the output end of the differential pressure flow meter is connected with the input end of the tail gas line emptying branch; the central controller