Ammonia removal
AssigneeThe Dow Chemical Company
InventorsJeffrey H. Stultz, Danford L. Bice
Life of this patent
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Abstract
A method for stripping ammonia from a film of digested sludge including flowing alkaline liquid sludge as a film on a tower's interior wall and flowing an ammonia stripping gas past the film creating a vapor containing ammonia and stripping gas; then disengaging the liquid sludge from the vapor in a tower disengaging zone.
Claims18
A method for removing ammonia from liquid sludge containing ammonia and suspended solids, the method comprising
- flowing the liquid sludge to an interior wall of an interior of a hollow stripping tower forming a flowing film of sludge on the interior wall, with the tower being at a positive pressure and with liquid sludge being supplied to the tower such that a wash rate is maintained in the tower of at least 5000 pounds per hour per foot of stripping tower periphery,
- flowing stripping gas past the film, stripping ammonia from the liquid sludge into the stripping gas, and
- disengaging liquid sludge from the stripping gas in a disengaging zone in the stripping tower, producing disengaged liquid sludge,
- flowing the stripping gas upwardly in the stripping tower, and
- flowing the liquid sludge downwardly in the stripping tower.
A method for removing ammonia from liquid sludge containing ammonia and suspended solids, the method comprising
- flowing the liquid sludge to an interior wall of an interior of a stripping tower forming a flowing film of sludge on the interior wall, with the tower being at a positive pressure and with liquid sludge being supplied to the tower such that a wash rate is maintained in the tower of at least 5000 pounds per hour per foot of stripping tower periphery,
- flowing stripping gas past the film, stripping ammonia from the liquid sludge into the stripping gas, and
- disengaging liquid sludge from the stripping gas in a disengaging zone in the stripping tower, producing disengaged liquid sludge,
- flowing the stripping gas upwardly in the stripping tower,
- flowing the liquid sludge downwardly in the stripping tower,
- flowing the liquid sludge to the interior wall of the stripping tower with a sludge distributor, and
- inhibiting foaming and sticking in the stripper tower by having no internal devices in the stripping tower below the sludge distributor.
A method for removing ammonia from digested denatured liquid sludge containing ammonia and suspended solids, the method comprising
- feeding the liquid sludge to a tank which is in fluid communication with an interior of a hollow stripping tower;
- flashing the liquid sludge into the tank producing stripping gas which flows to the stripping tower's interior, with the tower being at a positive pressure,
- adjusting the pH of the liquid sludge in the tank to at least 9,
- agitating the liquid sludge in the tank, and then
- feeding the liquid sludge from the tank to the stripping tower,
- flowing the liquid sludge to an interior wall of the stripping tower forming a downward flowing film of sludge on the wall interior,
- flowing stripping gas upwardly past the film, stripping ammonia from the liquid sludge and forming a vapor containing ammonia and stripping gas,
- disengaging liquid sludge from the vapor in a disengaging zone in the stripping tower, producing disengaged liquid sludge, and
- sensing ammonia concentration level of the disengaged liquid sludge through the stripping tower to remove at least 99% by weight of the ammonia.
Dependencies are inferred from the claim text.