# 60.421 Definitions.
As used in this subpart, all terms not defined herein shall have the meaning given them in the Act and in subpart A.
*Ammonium sulfate dryer* means a unit or vessel into which ammonium sulfate is charged for the purpose of reducing the moisture content of the product using a heated gas stream. The unit includes foundations, superstructure, material charger systems, exhaust systems, and integral control systems and instrumentation.
*Ammonium sulfate feed material streams* means the sulfuric acid feed stream to the reactor/crystallizer for synthetic and coke oven by-product ammonium sulfate manufacturing plants; and means the total or combined feed streams (the oximation ammonium sulfate stream and the rearrangement reaction ammonium sulfate stream) to the crystallizer stage, prior to any recycle streams.
*Ammonium sulfate manufacturing plant* means any plant which produces ammonium sulfate.
*Caprolactam by-product ammonium sulfate manufacturing plant* means any plant which produces ammonium sulfate as a by-product from process streams generated during caprolactam manufacture.
*Coke oven by-product ammonium sulfate manufacturing plant* means any plant which produces ammonium sulfate by reacting sulfuric acid with ammonia recovered as a by-product from the manufacture of coke.
*Synthetic ammonium sulfate manufacturing plant* means any plant which produces ammonium sulfate by direct combination of ammonia and sulfuric acid.