China CO2 Compressor Factory - Leading Suppliers for Urea Synthesis, Carbon Capture, and Refrigeration Systems

The core of a diaphragm compressor lies in its use of a metal diaphragm to completely physically isolate the compressed gas from the hydraulic oil system. The cylinder requires no lubrication. This means that during the entire compression process, carbon dioxide gas does not come into contact with any grease or oil mist, fundamentally eliminating oil contamination. For food-grade CO₂, electronic-grade CO₂, or CO₂ used in high-end chemical synthesis, this characteristic ensures extremely high cleanliness and chemical purity of the product gas, fully meeting the most stringent application standards.

The carbon dioxide gas is completely sealed within the "diaphragm cavity" formed by the diaphragm and cylinder head. This is a static sealing structure that theoretically achieves zero leakage. This not only effectively prevents the loss of valuable or hazardous gases, but also completely eliminates the asphyxiation safety risk caused by CO₂ accumulation in low-lying areas due to leakage. Simultaneously, this structure prevents potentially corrosive moist CO₂ from eroding the transmission components, enhancing the operational reliability of the equipment under harsh conditions.

Since carbon dioxide forms carbonic acid when co-existing with moisture, which is corrosive to ordinary carbon steel, all flow-wetted components in contact with CO₂—including the cylinder head, diaphragm, gas valves, and piping—must be manufactured from corrosion-resistant materials. Austenitic stainless steels (such as 304, 316L) are typically selected, and strict degreasing, cleaning, and passivation treatments are performed after manufacturing to ensure lasting corrosion resistance and gas purity.

The critical temperature of carbon dioxide is 31.03 °C. During compression, if cooling is insufficient and the gas temperature falls below this critical value while the pressure is high enough, a phase change to liquid is highly likely. Liquid CO₂ inside the compressor can cause a fatal "liquid hammer" phenomenon, damaging the diaphragm and cylinder head. The design must involve carefully calculating and controlling the compression ratio at each stage, and configuring high-efficiency interstage coolers (water-cooled or air-cooled) to ensure that the discharge temperature at each stage is effectively lowered. This strictly confines the operating points of the entire compression path to the gaseous region of CO₂, avoiding the risk of liquefaction.

Given the large coefficient of expansion of CO₂ under high-pressure storage (the pressure of a full cylinder can surge by 314 – 834 kPa for every 1 °C rise in temperature), the system must integrate multiple protections. Key design elements include: setting up accurate and reliable safety valves at each stage to prevent overpressure; equipping a diaphragm rupture detection and alarm device that can immediately alarm and shut down the compressor upon diaphragm failure to prevent gas-oil mixing; and installing gas concentration monitors in areas where CO₂ may accumulate, linked to the ventilation system. The control system (PLC) should integrate real-time monitoring and interlock shutdown functions for parameters such as pressure, temperature, and diaphragm status.