Control method for mixture ratio of phosphoric acid and liquid ammonia in production of diammonium phosphate

Abstract

The invention discloses a control method for the mixture ratio of phosphoric acid and liquid ammonia in the production of diammonium phosphate. A ratio of the phosphoric acid flow rate to the liquid ammonia flow rate is obtained in a distribution control system; the ratio is adopted as the input value of a ratio station; and then the output value of the ratio station is multiplied by the liquid ammonia flow rate to serve as a given value of cascade regulation of a phosphoric acid flow rate PID Proportion, Integration and Differentiation regulator to control the addition of the phosphoric acid, so as to control the mixture ratio. The method can automatically realize switchover without interference and automatic control through the ratio regulated by an operator and doesn't require the operator to calculate and regulate the mixture ratio, thereby greatly reducing the operation difficulty and ensuring more stable quality of the diammonium phosphate product.

Description

technical field [0001] The invention belongs to the technical field of diammonium phosphate production, and in particular relates to a method for controlling the proportioning ratio of phosphoric acid and liquid ammonia in the production of diammonium phosphate. Background technique [0002] In chemical production, there is often a production process of continuously controlling a certain amount of two materials for chemical reaction to obtain another material. In this continuous production process, accurately controlling the addition of two materials is the key to ensuring the quality of subsequent products. For example, the ratio of phosphoric acid and liquid ammonia, the two major raw materials for the production of diammonium phosphate, although the technical personnel can give the theoretical ratio of ammonia and acid, but due to the concentration of concentrated phosphoric acid, impurity content, and the amount of washing liquid added will vary. There is a certain chang...

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Problems solved by technology

For example, the ratio of phosphoric acid and liquid ammonia, the two major raw materials for the production of diammonium phosphate, although the technical personnel can give the theoretical ratio of ammonia and acid, but due to the concentration of concentrated phosphoric acid, impurity content, and the amount of washing liquid added will vary. There is a certain change, and the operator needs to adjust the amount of liquid ammonia and concentrated phosphoric acid in real time to change the ratio of ammonia and acid. After the manual adjustment of the flow of ammonia and acid changes, the control system cannot automatically track the changed ratio, which greatly reduces the Stability of Diammonium Phosphate Product Quality

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