Natural Gas Peak Shaving Station

With the further development of urbanization in China, the scale of urban population operation continues to expand, and the demand for natural gas will also grow. Coupled with the increasingly serious ecological and environmental problems, changing the energy structure and increasing the proportion of natural gas in the domestic primary energy consumption structure have effectively promoted the development of the natural gas industry, With the development and expansion of natural gas industry, peak shaving of urban gas storage is still a key course.

The gas consumption of city gas varies with time, which is non-uniform in month, day and hour. However, the gas supply of gas source is basically stable, which leads to the imbalance between gas supply and gas consumption. Sometimes the supply exceeds the demand, and sometimes the supply exceeds the demand. In order to alleviate the difference between uniform gas supply and uneven gas consumption, and ensure that all kinds of users can obtain sufficient flow and normal pressure of natural gas, it is necessary to take effective means of urban gas storage and peak shaving, that is, to store the surplus natural gas when the gas consumption is small, and to use it as supplementary gas when the gas consumption peak or the transmission and distribution system fails.

Technological process

After LNG is transported to the station by tank truck, the differential pressure between tank truck pressure and storage tank is greater than 0.2MPa by pressurization of unloading supercharger, and LNG in tank truck enters storage tank through differential pressure; When peak shaving gas supply is needed, the LNG of the storage tank enters the cryogenic pump through the discharge pipeline to pressurize to the process pressure. The pressurized LNG enters the LNG gasifier in turn to gasify into gas and the reheater to reheat to normal temperature. Then it is sent to the urban pipe network after being stabilized by the pressure regulating metering skid. In addition, LNG liquid can also be exported through loading pump and loading skid.

Bog gas generated in the process of loading and unloading is first collected in the gas phase space of the storage tank, then reheated by bog gas heater, pressurized by compressor to process pressure, and sent to the main pipe network to avoid waste. After gathering, EAG of the station is reheated to normal temperature and then discharged into the venting tower.

Equipment features

● The process characteristics of LNG station are "low temperature storage and normal temperature use". The design temperature of the storage tank can reach minus 196 ℃ (the boiling point of LNG at normal temperature is minus 162 ℃), and the temperature of the natural gas at the exit station shall not be lower than the ambient temperature of 10 ℃.

● The low temperature storage tank and low temperature liquid pump have good thermal insulation performance, and the valves and pipe fittings have good thermal insulation performance.

● The equipment, pipelines, instruments, valves and their accessories in the low temperature area of LNG station have good operation performance under low temperature conditions, good mechanical strength, sealing and corrosion resistance.

● The starting process of cryogenic liquid pump depends on the frequency converter to continuously increase the speed, so as to improve the power, increase the flow and provide high output pressure. Therefore, duel cryogenic liquid pump has high frequency, which can meet the requirements in a few seconds to more than ten seconds, and has good cold insulation performance.

● The manufacturing and daily operation management of low temperature storage tanks and filters have been incorporated into the national standards for manufacturing, acceptance and inspection of pressure vessels,