Strategically located at the entrance to the Hunter Valley, Orica Kooragang Island is an integral part of the company’s global operations and makes an important contribution to the local and broader Newcastle community. Kooragang Island's operations play a key role in the New South Wales economy, supplying critical products to the mining and infrastructure, agriculture, water supply, food, dairy and medical sectors.
Orica Kooragang Island is also a significant employer in the Newcastle area, with approximately 210 permanent employees and around 40 regular contractors. During plant shutdowns there are up to 150 additional employees on site.
The facility includes an ammonia plant, three nitric acid plants, two ammonium nitrate plants and a product dispatch facility.
Kooragang Island’s ammonia plant uses natural gas (methane) to produce approximately 360,000 tonnes of ammonia (NH3) per annum. This ammonia is used in the manufacture of nitric acid and ammonium nitrate, and is also sold for use as an agricultural fertiliser and a refrigerant.
The first stage of the ammonia manufacturing process involves the removal of sulphur from the natural gas using a catalyst and adsorbent material. The natural gas is mixed with steam and passed over a nickel-containing catalyst in the primary reformer to produce hydrogen, carbon monoxide and carbon dioxide.
The gas stream then passes to the secondary reformer where air is added to supply the nitrogen that’s needed to make ammonia. The mixture is then passed through a different nickel catalyst to complete the conversion of methane to hydrogen, carbon monoxide and carbon dioxide.
Two different catalysts in the shift converters are then used to convert carbon monoxide and water to carbon dioxide (CO2) and hydrogen.
Carbon oxides must be removed from the gas stream prior to the production of ammonia as they would otherwise destroy the catalyst. The CO2 is removed from the process gas stream using an amine solution which circulates through a CO2 removal tower. The carbon dioxide is then stripped from the amine solution and a portion is sold for use as a food preservative and to carbonate drinks.
The 3:1 mix of hydrogen and nitrogen gases is then compressed and fed to the ammonia converters where, in the presence of an iron catalyst, the nitrogen and hydrogen combine to form ammonia.
The gas from the ammonia converters is then refrigerated to –25˚C, liquefying the ammonia which is separated from the gas. This ammonia is then either used directly in the manufacture of nitric acid and ammonium nitrate, or stored in a refrigerated storage tank.
Nitric Acid Plants
Three nitric acid plants operate at the Kooragang Island site, converting ammonia into approximately 330,000 tonnes of nitric acid per annum.
In the nitric acid plants, ammonia is vapourised and then mixed with compressed air before being passed over a catalyst in a converter to form nitrogen oxides. Two of the plants use platinum as the catalyst, while a cobalt oxide catalyst is used in the third plant.
The process gas is then cooled and the recovered heat used either for the heating of gas streams or for the generation of steam, which operates turbines. The turbines drive the compressors that produce the compressed air for use in the process. The cooled process gas is then passed to an absorption column, where added water reacts with the nitrogen oxides in the gas to form 55-65 percent nitric acid.
The unused tail gases are then treated to further reduce the levels of nitrogen oxides (NOx) prior to discharge to the atmosphere. Tail gas is continuously monitored to ensure it complies with the required emission standards.
Ammonium Nitrate Plants
Approximately 400,000 tonnes of industrial grade ammonium nitrate is produced per annum onsite for use in the manufacture of explosives for the mining and quarry industries.
Ammonium nitrate is manufactured through the reaction of ammonia and nitric acid. Both solid and liquid ammonium nitrate products are produced onsite.
Ammonium nitrate product is supplied either in solution form or as one of two solid forms. The solid forms consist of a prilled product known as Nitropril® and a granulated product known as Opal™. The Nitropril® process involves the reaction of a mixture of nitric acid and vapourised ammonia in a neutraliser to produce an 83 percent ammonium nitrate solution. The solution strength is then increased in an evaporator and the concentrated solution is sprayed into a prill tower where it forms 1-3mm diameter solid balls of ammonium nitrate, called prill.
The prill is then dried with hot air and cooled in rotating drums before being screened and coated with an agent to improve the storage properties. The Orica Topan® process, which was developed on this site, is used to produce Nitropril®. Opal™ and ammonium nitrate solution are produced in a second plant, where nitric acid and vapourised ammonia are combined in a pipe reactor to produce a solution. Some of this solution is dispatched off-site for use in the manufacture of explosive emulsions and medical gases. The remaining solution is then passed through an evaporator to increase its ammonium nitrate concentration.
The concentrated solution is then sprayed into a fluidised drum granulator, where small spheres of solid ammonium nitrate are formed. The material is then screened to recover the 4mm-round ammonium nitrate product. The granules are coated with an agent to improve their storage properties. Undersized and oversized materials are returned to the granulator either directly or via a crusher. Solid ammonium nitrate products are stored in bulk inside an air-conditioned building. They are recovered for bulk dispatch or transferred to the bagging facility where they are loaded into 1.2 or 1.05 tonne bulk bags.
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