Variable Volume Phase Equilibrium Reaction Apparatus: The instrument consists of a variable volume stirred reactor, a gas mass flow meter, a buffer vessel, a stainless steel axial pressure gauge, pressure sensors and secondary display instruments, flexible heating packaging, a cooler, a gas-liquid separator, high-pressure ball valves, high-pressure needle valves, fine-tuning valves, data acquisition modules, and computers, etc. Main Technical Parameters: Operating Pressure: 50 MPa; Operating Temperature: 0~300℃; Mixing Speed: 120~800 r/min; Variable Volume Range: 150ml; Reactor Volume: 210ml; Inlet Flow Meter Range: 0~100ml/min; Equipment Purpose: Used for studying the phase changes of various substances within a system formed by solvents and solutes under changes in pressure (P), volume (V), and temperature (T).