Abstract: A method of cleaning a nitric acid absorption column is provided comprising: (a) cleaning its absorption column coil having an access port and an exit port by inserting a pig in the access port; maintaining pressure against the pig sufficient to force the pig through the coil; and capturing the pig after it passes through the exit port, and (b) cleaning the cooling fluid supply manifold headers and header hoses and the cooling fluid return manifold headers and header hoses by operatively connecting a valve means to a high pressure water or similar fluid supply to control the amount of high pressure water or similar fluid flowing through the valve means and into a flexible hose which has been operatively connected to the valve means to receive the high pressure water, operatively attaching a hollow tube having a nozzle provided with reverse direction orifices to the opposite end of the flexible hose to receive the high pressure water from the flexible hose and to allow the high pressure water to exit from the

Abstract: A method of cleaning a nitric acid absorption column cooling coil having an access port and an exit port comprising the steps of closing the access port, inserting a pig in an operative position within a sealable cavity of a launching assembly that is operatively attached to the access port to allow the pig to enter the coil, pressurizing the launching assembly with a fluid to a pre-determined level, opening the access port while maintaining pressure against the pig during its passage through the coil by a fluid pump sufficient to force the pig into and through the coil, and capturing the pig after it passes through the exit port.