A novel concept for a high energy and material efficient nitric acid production process and system is provided, wherein the nitric acid production process and system, particularly integrated with an ammonia production process and system, is configured to recover a high amount of energy out of the ammonia that it is consuming, particularly in the form of electricity, while maintaining a high nitric acid recovery in the conversion of ammonia to nitric acid. The energy recovery and electricity generation process comprises pressurizing a liquid gas, such as air, oxygen and/or N.sub.2, subsequently evaporating and heating the pressurized liquid gas, particularly using low grade waste heat generated in the production of nitric acid and/or ammonia, and subsequently expanding the evaporated pressurized liquid gas over a turbine. In particular, the generated electricity is at least partially used to power an electrolyzer to generate the hydrogen needed for the production of ammonia. The novel concepts set out in the present application are particularly useful in the production of nitric acid based on renewable energy sources.

A device for separating air by cryogenic distillation, comprising a first module containing a main air compressor, a second module, a third module containing a purification unit, a fourth module containing a heat exchanger and a system of columns comprising at least one distillation column that is or is not contained in the fifth module, the second module containing a connection for connecting the compressor of the first module to the purification unit of the third module in order to send compressed air from the compressor to the purification unit and also containing a connection for connecting the purification unit to the heat exchanger of the fourth module in order to send purified air in the purification unit to the heat exchanger.

A method for separating air by cryogenic distillation in a system of columns comprising a first column and a second column operating at a lower pressure than the first column, comprising the steps of compressing all of the feed air in a first compressor to a first output pressure of at least 1 bar greater than the pressure of the first column, sending a first portion of the air under the first output pressure to the second compressor, and compressing the air to a second output pressure, cooling and condensing at least a portion of the air under the second output pressure in a heat exchanger, withdrawal of a liquid from a column of the system of columns, pressurising the liquid and evaporating the liquid by heat exchange in the heat exchanger, and pressure reduction of a portion of the compressed air to a second output pressure, at least partially evaporating said air in the heat exchanger, optionally additional heating of said air in the heat exchanger, and sending at least a portion of this air to the second compressor.

A novel concept for a high energy and material efficient nitric acid production process and system is provided, wherein the nitric acid production process and system, particularly integrated with an ammonia production process and system, is configured to recover a high amount of energy out of the ammonia that it is consuming, particularly in the form of electricity, while maintaining a high nitric acid recovery in the conversion of ammonia to nitric acid. The energy recovery and electricity generation process comprises pressurizing a liquid gas, such as air, oxygen and/or N.sub.2, subsequently evaporating and heating the pressurized liquid gas, particularly using low grade waste heat generated in the production of nitric acid and/or ammonia, and subsequently expanding the evaporated pressurized liquid gas over a turbine. In particular, the generated electricity is at least partially used to power an electrolyzer to generate the hydrogen needed for the production of ammonia. The novel concepts set out in the present application are particularly useful in the production of nitric acid based on renewable energy sources.

A method for separating air by cryogenic distillation in a system of columns comprising a first column and a second column operating at a lower pressure than the first column, comprising the steps of compressing all of the feed air in a first compressor to a first output pressure of at least 1 bar greater than the pressure of the first column, sending a first portion of the air under the first output pressure to the second compressor, and compressing the air to a second output pressure, cooling and condensing at least a portion of the air under the second output pressure in a heat exchanger, withdrawal of a liquid from a column of the system of columns, pressurising the liquid and evaporating the liquid by heat exchange in the heat exchanger, and pressure reduction of a portion of the compressed air to a second output pressure, at least partially evaporating said air in the heat exchanger, optionally additional heating of said air in the heat exchanger, and sending at least a portion of this air to the second compressor.

A method of liquid air energy storage is provided. This method includes liquefying and storing air to form a stored liquid air during a first period of time; during a second period of time, introducing a compressed air stream into a cryogenic system, wherein the cryogenic system comprises at least one cold compressor, and at least one heat exchanger. The method includes producing a first exhaust stream and a second exhaust stream. The method also includes vaporizing at least part of the stored liquid air stream in the heat exchanger, thereby producing a first high pressure compressed air stream, then combining the first high pressure compressed air stream, the first exhaust stream and the second exhaust stream to form a combined exhaust stream, heating the combined exhaust stream, then expanding the heated combined exhaust stream in an expansion turbine to produce power.

A device for separating air by cryogenic distillation, comprising a first module containing a main air compressor, a second module, a third module containing a purification unit, a fourth module containing a heat exchanger and a system of columns comprising at least one distillation column that is or is not contained in the fifth module, the second module containing a connection for connecting the compressor of the first module to the purification unit of the third module in order to send compressed air from the compressor to the purification unit and also containing a connection for connecting the purification unit to the heat exchanger of the fourth module in order to send purified air in the purification unit to the heat exchanger.