Is it safe to have a high unloading pressure for propylene?
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It’s an propylene unloading compressor; the design pressure for the storage tank is 25 kg, while the design pressure for the tank truck is 19 kg. During unloading, air is drawn from the storage tank at a pressure of 16 kg and then pressurized to 24 kg. This clearly exceeds the design pressure of the tank truck by a large margin. I asked the compressor manufacturer, and they said there’s no problem. Experts, is there anyone who can explain this?
The safety valves on the tank trucks are about to blow
It’s 24 kilograms now, and the safety valve of the tank truck still hasn’t activated – that’s really impressive. The safety valve of the tank truck has been calibrated. Filling a tank truck to 24 kilograms is not allowed according to safety regulations; although it may be done occasionally in practice, over time the tank will reach its fatigue limit, which is very dangerous and can lead to explosions.
It’s not that it’s constantly inflated; the inflation pressure is used for unloading. It’s just that the pressure at the compressor outlet reached 24 Kg. The pressure in the tank truck is definitely less than 24 Kg
Although in reality tankers cannot reach 24 kilograms, if there is a mistake and the outlet of the tanker is closed, the pressure inside the tanker rises immediately, which is very dangerous.
The pressure ratio of this compressor is designed to be high; for unloading, a pressure difference of 2 kilograms is sufficient
Observe the body pressure. Make sure the vehicle’s pressure doesn’t exceed the limit.
Firstly, 24 kg is the outlet pressure of the compressor, not the pressure in the tank truck. The pressure of the tank truck depends on the gas phase pressure of the subsequent spherical tank, the hydrostatic head difference, pipeline resistance, etc. The following safety measures, if implemented in the design, can help reduce safety risks: 1. Install pressure gauges along the gas pipeline near the tank truck side for monitoring purposes. 2. Equip the gas pipeline with safety valves to prevent overpressure. 3. Unloading operations should be carried out when the pressure of the spherical tank is low; it is generally not allowed to do so when the ambient temperature is high.
Currently, domestic unloading compressors lack adequate safety features due to cost considerations. Designers should fully consider safety implications when designing.