SU483987A1 - Method for automatic control of distillation process - Google Patents

Description

The invention relates to a method for automatically controlling the process of distilling ammonia water and can be used in the coke and chemical industry. A method is known for controlling the distillation process by conducting laboratory one-off analyzes of the water after the column (determination of the content of ammonia and phenols), or control of the content of ammonia by the pH value of the waste water. A disadvantage of the known method is the low accuracy of determining the content of the individual components in the water after the ammonia distillation column. In order to eliminate this drawback, the content of the main components (ammonia and phenols) in water is determined by the flow rates and temperatures of steam, ammonia water and cold irrigation, vapor pressure, and pressure at the bottom of the column. The content of the components to be determined in the water after the destillation column is calculated according to the obtained equation of the connection Yi b, + AHX1 + UiiXl where Y is the content of ammonia in the water after the distillation column, g / l; Ultrasound — the content of phenols in water around the distillation column, g / l; 6- free member of a polynomial; bi, bii- coefficients for variables; yfi-steam consumption per column, t / h; Xz-flow of ammonia water on the column, X is the temperature of the water supplied to the column, ° C; X - water consumption, irrigation irrigation, Js-water temperature, and irrigation irrigation, ° С; Lb - steam temperature, ° С; X - vapor pressure, atm; Hy-pressure at the bottom of the column, atm. The automatic control of the content of components in the water after the distillation column in this method is carried out as follows. Signals that are proportional to the measured input technological parameters of the distillation process — flow rates and temperatures of steam, ammonia water and cold irrigation, vapor pressure and pressure at the bottom of the column, on the value of which depend the determined content of components in the water after the column; which implements the resulting mathematical model. Diagram of the device that implements this method is presented in drawing.

The device contains elements 1-8 multiplied by a constant coefficient, multiplier-dividing blocks 9-16, three-input adders 17-24, unit 25, amplifier and repeater 26.

The measuring device operates as follows.

The pneumatic signals of the RL-, -P.V, from the primary measuring devices are fed to the elements 1-8 multiplying a constant coefficient and to the multiplying-dividing blocks 9-16, where squaring is performed. The outputs of elements 1-8 and blocks 9-16 are connected to three-input adders 17-24. Unit 25 serves to input into the device the free term of the equation. The output signal of the measuring device is proportional to the content of the component being detected.

(ammonia or phenols, depending on the type of equation to be implemented) in water along the distillation column. This signal from amplifier Repeater 26 is fed to the secondary meter.

Subject invention

A method for automatically controlling the distillation process by output parameters, characterized in that, in order to determine the content of individual components in the water after the ammonia distillation column, the flow rates and temperatures of steam, ammonia water and cold irrigation, vapor pressure, pressure at the bottom of the column and these parameters determine the content of the components in the water.