Liquefied Petroleum Gas (LPG) is highly prone to vaporization during storage and transportation, forming a gas-liquid two-phase flow. When the bubble ratio increases (especially during suction from underground tanks or unloading, where the gas content can reach 50%), conventional centrifugal pumps encounter critical issues:
1、Cavitation nightmare: Bubbles burst in the low-pressure area of the impeller, causing intense shock and damaging the pump body, resulting in a sudden interruption of the flow and stopping of the pump.
2、Efficiency plummeting: Gases occupy the flow channels, significantly reducing the effective liquid delivery volume, while energy consumption surges.
3、Unstable operation: The flow pressure fluctuates sharply, failing to meet the requirements for continuous operations (such as bottle filling, tanker loading and unloading).
The special multi-stage centrifugal pumps, such as the lpg multistage pumps, have solved the problems through their unique design:
Location：The front end of the suction inlet of the pump
Function: Just like the "bubble handler", before the liquid enters the main impeller, it gently but effectively compresses the gas-liquid mixture.
Result: Significantly reduce the required net positive suction head rise (NPSHr). This means that the pump can start and operate smoothly even under extremely demanding suction conditions (such as low liquid level in underground tanks and high pipeline resistance) or with a high gas content (≤ 50%), fundamentally preventing cavitation.
Structure: Use 6-stage (LPGP-65) or 8-stage (LPGP-85) impellers in series.
Strategy: The total pressure difference is distributed among multiple impellers, and the pressure is gradually and smoothly increased at each stage.
Sealing: Use a non-cooling mechanical seal. Eliminate the complex cooling system, eliminate the possibility of coolant leakage contaminating LPG or causing safety risks, and make the seal more reliable and maintenance easier.
Bearings: Pump end sliding bearing + Drive end ball bearing combination. The sliding bearing has strong load-bearing capacity and operates smoothly; the ball bearing has high efficiency and can adapt to high speed (1450 RPM), jointly ensuring long-term stable operation.
Structure: Horizontal split design. It is convenient for inspecting and maintaining internal components (such as the impeller and seals), and the maintenance is highly convenient.
These specialized multi-stage pumps are not just equipment, but also the key guarantee for safety and efficiency. Through innovative design, they have successfully tamed the "bubble beasts" in the transportation of gaseous liquefied gas, resulting in:
Work is safer: Reduces cavitation damage, eliminates the risk of coolant leakage, and ensures stable and reliable operation.
Operate more efficiently: Adapt to harsh conditions, ensure continuous production, and reduce maintenance costs and downtime.
More widely applied: It has unlocked key scenarios that traditional pumps were unable to handle, such as extracting from deep tanks and high-pressure filling.
-
