The Inert Gas System (Unit 4800) consists of four Air Separation Units ASU-1/2/3/4. These units produce high purity gaseous and liquid Nitrogen (GAN and LIN) which is used in the NLNG complex:
- To purge and dry out systems before start-up or shutdown.
- As make up to the LNG trains MR circuit.
- To maintain inert atmosphere in some sections of the LNG trains and water storage tanks.
- To purge flare headers and stacks.
- To purge the LNG loading arms before and after each loading operation.
The continuous supply of the required quantities of nitrogen is critical for safe operation of the plant and can directly impact LNG production. The need for a nitrogen capacity enhancement project arose due to increased site demand for Nitrogen, loss of sparing and to meet future asset rejuvenation requirements.
A feasibility and concept select study has been performed which identifies that an additional 80 t/d gaseous Nitrogen generation package together with a 2 x 200 t/d instrument air compressor packages will meet the NLNG nitrogen production and instrument air supply redundancy requirements respectively.
