SU710597A1 - Method of purifying waste gases of nitrogen acid decomposition of phosphate raw material - Google Patents

Description

one

The invention relates to the field of purification of gas emissions of nitric acid decomposition of phosphate raw materials and can be used in the production of nitrophos.

Known methods of gas cleaning from nitrogen oxides using ammonia and carbamide 1 and 2.

The known methods are not suitable for the purification of gases of nitric acid decomposition of phosphate raw materials, which contain a mixture of nitrogen oxides, gaseous fluorine compounds and ammonia.

The closest in technical essence and the achieved result to the proposed is the method of purification of the exhaust gases of nitric acid decomposition of phosphates, which consists in the absorption of acidic impurities by soda solution 3.

However, the known method is not efficient enough and does not allow continuous cleaning process due to the formation of sparingly soluble salts that clog heat exchangers and pipelines.

The purpose of the invention is a more complete absorption of nitrogen oxides, fluorides.

compounds and ammonia while simplifying the process.

This goal is achieved by the fact that during the purification of the exhaust gases of nitric acid decomposition of phosphate raw materials, when obtaining complex fertilizers by sorption of the exhaust Gases with alkaline solutions, a mixture of carbon ammonium salts and urea is used as the alkaline solutions; wt.% in terms of ammonia, and urea by

5 weight ratio with incoming nitrogen oxides (0.51, 0): 1 for purification, with a weight ratio of components ННз: СО (N11) 2: СО2 (1-2) :( 0.25-1): (1, 3-5,2).

0

Example. Gas containing 5 g / nm of nitrogen oxides, 1.5 g / nm of fluorine compounds and 1 g / nm of ammonia

from the nitrophosphate production reactors in the amount of 24,000 nm / hour, enters the absorber. The fresh, rationed solution comes from the carbamide shop and is mixed with the circulating solution, which is cooled before and goes to the absorber irrigation. A fresh solution has the following composition; carbamide 1%, ammonia 2%, C02 3.9%. The amount of fresh solution is 2.5. Spent

the solution is withdrawn to the reactor compartment to dilute the pulp.

The obtained data on the purification of flue gases by known and proposed methods are presented in the table.

Claims (2)

Claim 1. The method of purification of waste gases of nitric acid decomposition of phosphate raw materials in the preparation of complex fertilizers by sorption of waste gases with alkaline solutions, characterized in that, in order to more fully absorb nitrogen oxides, fluoride compounds and ammonia while simplifying the process, a mixture is used as alkaline solutions a solution of carbon ammonium salts and urea. 2. The way pop, 1, characterized in that, the concentration of carbon ammonium salts take 0.5- 10 wt.% In terms of ammonia, and urea by weight ratio with nitrogen oxides coming for purification (0.5-1.0): 1, with a weight ratio of components NHg: СО (NH ₂ ) ₂ : СО ₂ = ( 1-2): (0.25-1): (1.3-5.2).