Abstract:

There is much energy in high pressure natural gas pipeline network，and about 322 kJ/kg pressure energy can be recycled from the depressurization process of natural gas at 25℃ from 4.0MPa to 0.4MPa，however，only a little of which was recycled in the actual depressurization process. This paper describes tow recycling methods of natural gas pressure energy from high-pressure pipeline network，power generation and refrigeration. For power generation，combined with the technology of waste heat recovery and gas turbine inlet air cooling，there are mainly three power generation modes；for refrigeration，the cold energy from natural gas expansion cooling is mainly used for natural gas peak shaving，cold storages，cold water air conditioners，rubber cryogenic grinding and light hydrocarbon recycling. In order to improve the utilization efficiency of natural gas pressure energy，and to expand the flexibility of system operation，a new technology is proposed，which can recover the output power of turbo-expander for compressing refrigerant in the refrigeration system while high pressure natural gas is expanded for low temperature. Thus，the proposed new technology can substantially improve the refrigeration efficiency.