2016 Pattabathula The Safety and Integrity of Ammonia Storage Tanks
Ammonia is an important raw material for the fertiliser industry and more than 150 million tonnes of ammonia is produced worldwide per year. About 20 million tonnes of ammonia is traded every year at the international level and the rest is consumed locally for the manufacture of fertilizers and industrial chemicals.Storage of liquid ammonia had been a practice for almost 100 years right from the time ammonia was made on an industrial scale. In the earlier stage of ammonia production, ammonia was stored in pressurised systems such as bullets and in Horton spheres. Typically, spheres were used to store up to 2000 tonnes whereas atmospheric ammonia storage tanks are used to store up to 50,000 tonnes at plant sites and also at separate distribution terminals near to where liquid ammonia is applied directly. Low pressure ammonia storage has been widely accepted for two reasons. First, it requires much less capital per unit. Second, it is safer than sphere storage using pressures higher than atmospheric. With the large scale industrial production of ammonia, it has become common to store ammonia at atmospheric pressures at -33°C.