Method for removing ammonia and dust from a waste gas that results during the production of fertilizers

• US 20070039469A1
• Filed: 09/04/2004
• Published: 02/22/2007
• Est. Priority Date: 10/02/2003
• Status: Active Grant

• Current Assignee: Thyssenkrupp Uhde GmbH (Thyssenkrupp AG)
• Original Assignee: UHDE GmbH (Thyssenkrupp AG)
• Inventors: Franzrahe, Harald, Niehues, Paul
• Granted Patent: US 7,682,425 B2
• Time in Patent Office: Days
• US Class Current: 95/199
• CPC Class Codes: B01D 53/58 Ammonia
• CPC Class Codes: C05C 3/00 Fertilisers containing other salts of ammonia or ammonia itself, e.g. gas liquor
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Abstract

The invention relates to a method for removing ammonia and dust from a waste gas that occurs during the production of fertilizers, preferably urea, in which method the waste gas is introduced into a first washer, and a cooling gas is introduced into the one washer and an aqueous solution is introduced into the other washer, whereby both the waste gas and the cooling gas pass through at least one mist collector before exiting from the washer, in each instance, is supposed to be developed further in such a manner that the waste gas pollution can be clearly reduced. This is accomplished in that the additional water is first introduced into a fine-washing area of the first washer, delimited by the mist collector on the top and by a liquid-impermeable partition bottom at the bottom, and sprayed onto the at least one mist collector, and the aqueous solution that forms in the fine-washing area is subsequently passed into the second washer.

Claims

1. Method for removing ammonia and dust from a waste gas that occurs during the production of fertilizers, preferably urea, in which method the waste gas is introduced into a first washer, and a cooling gas is introduced into a second washer, and additional water is introduced into the one washer and an aqueous solution is introduced into the other washer, whereby both the waste gas and the cooling gas pass through at least one mist collector before exiting from the washer, in each instance, wherein the additional water is first introduced into a fine-washing area of the first washer, delimited by the mist collector on the top and by a liquid-impermeable partition bottom at the bottom, and sprayed onto the at least one mist collector, and the aqueous solution that forms in the fine-washing area is subsequently passed into the second washer.

2. Method according to claim 1, wherein the aqueous solution that exits from the second washer is introduced into the main washing area of the first washer, provided below the partition bottom, into which the waste gas also enters.

3. Method according to claim 1 wherein a bell-shaped bottom is used as the partition bottom.

4. Method according to claim 1, wherein an acid is introduced into the fine-washing area of the first washer.

5. Method according to claim 1, wherein a urea concentration of 40-60%, preferably 55% is set in the main washing area of the first washer.