Method and apparatus for continuous conversion production of sodium nitrate

Abstract

The invention discloses a method and an apparatus for continuous conversion production of sodium nitrate, and belongs to the technical field of production of inorganic chemical engineering products. The method mainly comprises the processes of mother liquor pre-conversion, conversion absorption and tail gas separation. The system of the apparatus mainly comprises a conversion absorption tower, a converter, an absorption separator, a matching pump and a matching pipeline, and the conversion absorption tower is a packed tower, and comprises an upper portion pre-conversion segment, a middle portion conversion absorption segment and a lower portion solution storage tank; and a conversion solution obtained after pre-conversion and conversion reactions of a mixed mother liquor and a circulating solution enters the solution storage tank, parts of the conversion solution returns to the conversion absorption tower through a conversion circulating pump, the remaining conversion solution is pumped into the converter in order to produce solid sodium nitrate, and generated tail gas is sent to a 4# alkali absorption tower, and is absorbed to produce sodium nitrite. The method and the apparatus optimize technological operation, improve the sodium nitrite conversion rate and the qualified rate of sodium nitrate, enlarge the productivity, reduce the production cost, realize continuous and automatic production of sodium nitrate and are in favor of realizing energy saving and emission reduction.

Description

technical field [0001] The invention relates to a method and equipment for continuously transforming and producing sodium nitrate, belonging to the technical field of inorganic chemical product production. Background technique [0002] In modern industrial production, sodium nitrite mother liquor conversion (also called nitration) method is generally used to produce sodium nitrate. The main process is: the nitrogen oxides produced by ammonia oxidation are absorbed by the waste heat boiler and directly enter the alkali absorption tower, and the raw material liquid is prepared to obtain a mixed solution of sodium nitrate and sodium nitrite, and sodium nitrite is obtained through evaporation, crystallization and separation. ; Sodium nitrite mother liquor is converted into sodium nitrate through conversion process. The reaction formula of sodium nitrite mother liquor conversion is ： [0003] 3NaNO 2 +2HNO 3 = 3NaNO 3 +2NO+H 2 o [0004] The transformation of sodium nitri...

AI Technical Summary

Problems solved by technology

The flow rate of the mixed liquid entering the conversion tower in the traditional batch conversion device is small, and the spray density in the tower is small, which leads to insufficient oxidation reaction of the mother liquor, long conversion time, low production capacity, difficult control of conversion rate and conversion end point, and sodium nitrate product. The pass rate is low, and the tail gas of the conversion tower contains condensed acid, which leads to problems such as liquid entrainment, liquid leakage and overpressure

The Chinese patent No. 2009100758210 discloses a "method for producing sodium nitrate through continuous conversion without stirring". Composed of pipelines, the invention realizes the continuous conversion production of sodium nitrite and has achieved good results, but the patent requires three tower equipment, the process operation is relatively complicated, the equipment occupies a large area, the investment cost is relatively high, and the equipment is easily affected by high temperature. Acid corrosion, since the conversion is carried out continuously in the conversion tower, the quality of the conversion liquid pumped out by the circulating pump has the problem of inaccurate control, which affects the qualification rate of sodium nitrate to a certain extent

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