Automatic LNG and CNG switching system and control method thereof

Abstract

The invention relates to an automatic LNG and CNG switching system and a control method thereof. The automatic switching system comprises a control system, an LNG supply sub-system and a CNG supply sub-system, wherein the LNG supply sub-system and the CNG supply sub-system are connected in parallel. Heat exchange of the LNG supply sub-system and the CNG supply sub-system is achieved through a shared heat exchange tank. The shared heat exchange tank comprises a tank body, heaters, two-stage CNG heat exchange pipes and an LNG heat exchange pipe. The control system comprises a first stop valve, a first temperature transmitter, a first pressure transmitter, a second stop valve, a second temperature transmitter, a second pressure transmitter and a third temperature transmitter, wherein the first stop valve, the first temperature transmitter and the first pressure transmitter are arranged on the LNG heat exchange pipe; the second stop valve, the second temperature transmitter and the second pressure transmitter are arranged on the CNG heat exchange pipes; and the third temperature transmitter is arranged on the tank body. According to the technical scheme, switching of different gas source gas supply sub-systems is achieved through control of the control system, continuous gas supply can be achieved by fully using an in-place gas source or a standby gas source, work and production stopping caused by gas supply shortage of any natural gas source is prevented, and economic losses of users are avoided.

Description

technical field [0001] The invention relates to a gas supply system, in particular to an automatic switching system between LNG and CNG and a control method thereof. Background technique [0002] In the gas supply system, due to reasons such as rising gas prices and mining conditions, many gas users generally abandon the use of liquefied petroleum gas (LPG) and use natural gas for gas supply. Due to restrictions on transportation and other conditions, many users cannot use pipeline natural gas for gas supply, and instead use tank trucks for gas supply. Now natural gas tank trucks are more commonly used as LNG tank trucks and CNG tank trucks. Although LNG and CNG belong to natural gas, they are relatively The corresponding gas pressure regulating device is not universal. Therefore, if the gas supply of one of the natural gas sources is tight, the lack of gas can be detected in time or the gas supply mode can be automatically switched according to the gas source in place, whi...

AI Technical Summary

Problems solved by technology

Due to restrictions on transportation and other conditions, many users cannot use pipeline natural gas for gas supply, and instead use tank trucks for gas supply. Now natural gas tank trucks are more commonly used as LNG tank trucks and CNG tank trucks. Although LNG and CNG belong to natural gas, they are relatively The corresponding gas pressure regulating device is not universal

Therefore, if the gas supply of one of the natural gas sources is tense, the lack of gas can be detected in time or the gas supply mode can be automatically switched according to the gas source in place, which will easily cause production stoppage and bring economic losses to users

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