US Patent 10141814 Liquid cryogen vaporizer method and system

Liquid cryogen from a tank having a head space pressure P1 is vaporized with a pressure building vaporizer to gaseous cryogen and the pressure of the gaseous cryogen is built to a pressure P2. The pressurized gaseous cryogen at pressure P2 is expanded across an expander to decrease its pressure and fed to a point of use at an installation including the vaporizer at a pressure P3. P2≥2×P3. Energy from the expanded gas may be recovered in the form of mechanical energy, electrical energy.