Method and plant for the production of ammonia with renewable energy

A method of modifying a pre-existing plant for the production of ammonia, said pre-existing plant comprising:

• a catalytic reactor having a nitrogen inlet for a nitrogen feed, a hydrogen inlet for a hydrogen feed, and an ammonia outlet for produced ammonia;
• a hydrogen providing section having a hydrogen outlet for hydrogen, said hydrogen outlet being in fluid communication with the hydrogen inlet of the reactor;
• a nitrogen providing unit having at least one air inlet for an air stream, an oxygen outlet for an oxygen enriched stream, and a nitrogen outlet for a nitrogen stream;
• said nitrogen outlet being in fluid communication with the nitrogen inlet of the reactor;
• an electrical control unit configured to power the plant;
• the method comprising adding to the pre-existing plant:
• an electrolysis unit having a water inlet for a water feed, an oxygen outlet for oxygen, and a hydrogen outlet for hydrogen, said hydrogen outlet being in fluid communication with the hydrogen inlet of the reactor;
• a low pressure air compression and adsorber section, having an air inlet for an external air feed and an air outlet for LP compressed air, said air outlet being optionally in fluid communication with an air inlet of the nitrogen providing unit and being in switchable fluid communication with either an air liquefaction section, or a high pressure air compression unit having an outlet for compressed air in fluid communication with the air liquefaction section, said air liquefaction section comprising a turboexpander configured to drive a generator to provide a first energy source;
• a liquid air storage having a liquid air inlet for liquid air obtained from the air liquefaction section, a closable outlet for liquid air in fluid connection with the nitrogen providing unit, and a closable outlet for liquid air in fluid connection with a generator section configured to provide a second energy source and an expanded air stream;
• said generator section having an air outlet in fluid connection with an air inlet of the nitrogen providing unit;
• and arranging that the plant has a power connection with a renewable energy source and with the first and second energy sources, and configuring the electrical control unit such as to be switchable between the renewable energy source and the first and second energy sources, including combinations thereof.