City Peak-Shaving StationIt is a peak-shaving station for liquefied natural gas, mainly addressing the contradiction between the uniform supply of natural gas infrastructure and the uneven gas consumption by natural gas users. It adopts gas supply and consumption debugging management measures that ensure user gas demand while guaranteeing the safe, stable, and economical operation of natural gas infrastructure.

City natural gas gate stations and storage and distribution stations are important infrastructure in the urban natural gas transmission and distribution system. Among them, the gate station is the gas source point of the urban transmission and distribution system and is also the gas distribution station where the long-distance natural gas pipeline enters the urban gas pipeline network. Its task is to receive the gas transported by the long-distance pipeline, filter, regulate pressure, measure, deodorize, and distribute it within the station, and then deliver it to the urban transmission and distribution pipeline network or directly to large users. The main function of the high-pressure natural gas storage and distribution station is to store gas, reduce pressure, and deliver it to the urban gas pipeline network. To ensure the normal operation of the storage and distribution station, the gas coming out of the high-pressure main pipe must be filtered, odorized, and measured before entering the pressure regulator.

After the LNG transport ship arrives at the unloading dock, LNG is transported from the transport ship's pump through the LNG unloading arm and unloading manifold to the LNG storage tank. After LNG enters the storage tank, the evaporated gas released will return to the LNG ship's hold through the return gas pipeline and gas phase return arm to maintain pressure balance in the unloading system. During the unloading process, the working pressure of the LNG storage tank is slightly higher than that of the LNG ship. Due to the high design pressure of the onboard single-wall metal storage tank, to ensure that the evaporated gas returns to the hold, the evaporated gas is pressurized by the shore's evaporated gas return fan before being sent back to the transport hold. The return air pressure can be automatically controlled by a regulating valve.

　　City Peak-Shaving StationThe main functions include vaporization, filtration, pressure regulation, measurement, gas quality detection, safety release, safety cutoff, automatic switching between service lines and backup lines, etc. It is required to design multiple safety measures to ensure long-term, safe, and stable gas use while ensuring accurate pressure regulation and flow measurement.

During the design, consideration should be given to whether its functions can meet the gas scheduling and peak-shaving requirements of the transmission and distribution system. According to the scheduling requirements of the transmission and distribution system, the measurement and pressure regulation devices should be designed in groups, with filters set before the devices. The pressure regulation device should determine whether a heating device is needed based on process conditions (such as gas flow and pressure drop). Cut-off valves and insulating flanges should be set at the inlet and outlet of the pipeline, and safety protection and discharge devices should be set on the station's internal pipeline according to system requirements. A separator should be set in the inlet manifold of the gate station. When the long-distance pipeline uses pigging technology, the pig receiver device can be arranged within the gate station.

The process flow of the city peak-shaving station should be determined through technical and economic comparisons based on the nature of the gas source, urban scale, load distribution, and pipeline pressure grade system. The role of the pressure regulator is to reduce the pressure of high-pressure gas to the working pressure of the high-pressure storage tank, thus storing it in the storage tank. The role of the secondary pressure regulator is to adjust the gas pressure to the working pressure of the outgoing pipeline. Depending on different needs, in addition to the main process equipment such as gas storage, pressure transmission, and pressure regulation, there are also auxiliary production facilities, living facilities, and fire protection facilities. The selection of the city peak-shaving station should consider requirements such as process, power, water supply and drainage, civil installation, fire and explosion protection, and environmental protection, as well as their impact on investment and operating costs, and coordinate with the overall urban planning. The process layout should ensure reliable operation, production safety, and convenient operation management.