A device and method for unloading a liquefied natural gas tank car

Abstract

The invention relates to a liquefied natural gas tanker unloading device and a liquefied natural gas tanker unloading method. Liquefied natural gas and BOG in the liquefied natural gas tanker are unloaded to a liquefied natural gas storage tank; the unloading device comprises a compressor and a cooling exchanger; the unloading device is used for sending residual BOG in the tanker into the liquefied natural gas storage tank through the compressor and the cooling exchanger. The unloading device has the beneficial effect that the BOG on the tanker is pumped out through a compressor, the low-temperature BOG is sent into the liquefied natural gas storage tank through the cooling of the cooling exchanger and exchanges coolness with the low-temperature liquid in the storage tank so as to be condensed into liquid; the BOG can be comprehensively and automatically recycled, the operation is convenient, the recycling efficiency is high, and the recycling is clean and lossless.

Description

technical field [0001] The invention belongs to liquefied natural gas transportation technology, in particular to a device and method for unloading a liquefied natural gas tank car. Background technique [0002] At present, when the tank trucks transporting liquefied natural gas (LNG) at the domestic LNG refilling station are unloaded at the refueling station, there is a problem of unclean unloading, especially the liquefied natural gas volatile gas (BOG) in the tank car is ultra-low temperature. The gas cannot be discharged into the storage tank according to people's wishes. Auto refueling stations generally use LNG pumps to unload vehicles, or use LNG self-superchargers to pressurize tank vehicles to form pressure differences for unloading vehicles. When the LNG pump is used to unload the truck, when the liquid in the tank car is unloaded, the unloading truck will automatically close to complete the unloading. At this time, there is still high-pressure low-temperature BOG...

AI Technical Summary

Problems solved by technology

In order to reduce the weight of the vehicle, to facilitate loading, and to reduce the tare weight to meet the user's need to check the volume, the driver often discharges BOG into the air after unloading the vehicle. This not only increases the risk, but also causes a lot of waste. Publication number CN201964142 Disclosed a "LNG pumpless gas filling equipment with BOG recovery function". Nitrogen storage tanks are used to recover BOG. ​​The liquid nitrogen condensing device is installed in the LNG storage tank, which occupies the space of the LNG storage tank. For the liquid nitrogen condensing device, a liquid nitrogen cold hydrazine should be installed outside, and the connection control is not easy. Convenient, and the tanker does not carry a liquid nitrogen storage tank separate from the tanker

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