Optimal control system for lng filling station

Abstract

The invention relates to an LNG (liquefied natural gas) filling station optimization control system. According to the LNG filling station optimization control system, DCS control is adopted. The LNG gas filling station optimization control system comprises a DCS control system which controls an LNG storage tank, a pump sump, add liquid adding circulation and metering. The control functions of the batch controller of filling machines are realized by a DCS. In order to ensure that a liquid-phase pipeline is filled with a liquid-phase substance in LNG filling, LNG is subjected to minor circulation and major circulation under control, a situation that a high-precision mass flowmeter drives gain signal output to change is detected in minor circulation and major circulation processes, so that different gain signal output can be realized under a liquid-phase state and a gas-phase state, and when the system judges the flowing state in the pipeline is a liquid-phase state, and no gas exists in liquefied natural gas flowing through the mass flowmeter, pre-cooling termination is displayed, and minor circulation and major circulation are terminated. Automatic gas collection and exhaust functions of BOG are configured technically, a pre-cooling process is not required; a LNG liquid collector and a LNG gas collector are arranged on a technique pipeline; the liquid level of the liquid collector is in a proper level under the DCS control; and when liquid filling is not carried out, the LNG liquid-phase pipeline is filled with liquid, a gas-phase substance is communicated with an LNG storage tank through the gas collector, and BOG generated by the technique pipeline due to heat loss can be exhausted timely to a gas-phase space connected with the LNG storage tank through the gas collector.

Description

technical field [0001] The invention belongs to the field of new energy transmission and measurement, and in particular relates to an optimization control technology for selection of instruments and valves and a control system of an LNG filling station. Background technique [0002] At present, the LNG sub-station control is the batch controller used on the liquid injection machine or gas dispenser plus the station control system. Most of the batch controllers are Siemens S200 system; the valves (inlet valve, return valve, exhaust valve) and instruments (quality, pressure, temperature) in the liquid injection machine are directly connected to the batch controller, and the batch controller completes the internal control of the liquid injection machine. Measure and control. Most of the station control system is Siemens S300 system. Except for the automatic control equipment connected to the liquid injection machine, all instruments, valves and station control systems are conn...

AI Technical Summary

Problems solved by technology

[0003] There is a problem: when the batch controller S200 of the liquid injection machine fails, the liquid injection machine cannot work

[0005] Existing problems: the above process method, the operation of the LNG submersible submersible pump requires power consumption, and the power consumption is eventually converted into heat, and the heat generation will generate more BOG gas

[0008] At present, most LNG cut-off valves use cut-off valves, which are slow to close and have large leakage

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