System for storing and producing energy to stabilize the power network

A process for producing liquid oxygen and liquid oxygen-depleted air, and optionally natural gas, said process using electricity said process comprising subjecting an air flow withdrawn from a source to the steps of:

• I) pre-treatment, wherein the air flow is subjected to the steps of:
• Ia) compression in a compressor, obtaining a compressed air flow,
• Ib) cooling of said compressed air flow in a cooler, obtaining a compressed and cooled air flow, and
• Ic) separation in a first separator of a condensed vapor flow from the bottom of said separator and of a compressed and cooled gaseous flow from a head of said first separator,
• II) treatment, wherein the compressed and cooled gaseous flow is subjected to one or more purification operations to obtain a purified air flow,
• III) heat exchange, wherein the purified air flow is subjected to thermal exchange with a cooling medium, obtaining a purified and cooled air flow,
• IV) separation, comprising the following sub-steps:
• wherein a preliminary step IVa) is carried out, in which the purified and cooled air flow is subjected to cooling inside a reboiler of a distillation column, obtaining a partially condensed flow from which, in a step IVb), a second condensed liquid air flow is separated within a second separator from a bottom of the second separator, and laminated by a first lamination partially vaporized by a first valve, thereby obtaining a partially vaporized current that is fed to the distillation column, and a gaseous flow is separated from a head of said second separator and expanded in a turbine with power generation, obtaining an expanded flow that is fed to the distillation column, obtaining an oxygen flow from the reboiler, a second portion of the oxygen flow being sent to a first tank, and an oxygen-depleted air flow is obtained from a head of said distillation column,
• Va) obtaining a liquid oxygen flow and a gaseous oxygen flow from said oxygen flow,
• Vb) obtaining a liquid oxygen-depleted air flow from said oxygen-depleted air flow, wherein in step Vb), the oxygen-depleted air flow is subjected to a first heat exchange step, obtaining a heated oxygen-depleted air flow, which is subjected to steps of:
• compression, obtaining a compressed flow,
• cooling, obtaining a compressed and cooled flow, to which a heated recycled gas flow is added, obtaining a second flow, which is
• compressed, obtaining a second compressed flow, which is cooled, obtaining a further compressed and further cooled flow, which is
• subjected to a second heat exchange step in a heat exchanger with which the further compressed and further cooled flow is cooled, obtaining an at least partially condensed flow, which is
• expanded in an expander, obtaining a further condensed flow and with power generation, from which
• inside a third separator, separating a gaseous head flow from a head of the third separator from the liquid oxygen-depleted air flow from a bottom of the third separator, the gaseous head flow being heated in a third heat exchange step within the heat exchanger to provide the heated recycled gas flow and the liquid oxygen-depleted air flow from the bottom of said third separator is sent to a second tank for the liquid oxygen-depleted air, wherein the second and third heat exchange steps in the heat exchanger are carried out using frigories of a refrigeration cycle that uses liquefied natural gas.