Re-Concentration of Weak Sulfuric Acid
The dilute sulfuric acid stream coming off the bottom of the Extractive Distillation Column is preconcentrated back to the same service by using Ablaze sulfuric acid re-concentration plant, which can be coupled directly with the nitric acid concentration system so that no cooling of the weak sulfuric acid is necessary, thus saving a large amount of heating energy for the economic benefit of the user.
The NOx gases escaping from the Nitric acid Concentration System, along with bleaching air, are absorbed in Ablaze special NOx absorption plant and is recycled back into the main system as an aqueous solution of nitric acid, at concentration comparable to those of the nitric acid feed to the same System : the residual gases vented to the atmosphere have NOx. The content below the acceptable values as per environmental norms.
Nitric Acid Concentration
Concentrated Nitric Acid CNA ( i.e. high-strength nitric acid at 98 -99% w/w.) is an important chemical for Chemical & Pharmaceutical industries in general (like polymers & plastics, dyestuff, bulk drugs, explosives, Fertilizers, and other important organic nitro-compounds). This acid is frequently used as “nitrating acid”.
Owing to its chemical properties nitric acid cannot be concentrated by fractional distillation above 68 % as it forms an azeotrope with water. To reach a concentrated nitric acid concentration with up to 99 % the water needs to be extracted by using an extractive agent (e.g. sulfuric acid).
To concentrate this acid further an extractive distillation process by adding concentrated sulfuric acid needs to be employed. While the water goes this sulfuric acid gets diluted, which can be again re-concentrated and reused for the concentration of dilute nitric acid again.
Pre-concentration of weak Nitric Acid solution
Whenever a solution of Nitric Acid is too weak for direct Extractive Distillation (typically below 45% -50% w/w.), it can be pre-concentrated to its azeotropic grade by our vacuum Fractional Distillation plant.