SU1754726A1 - Method for control of azeotropic drying of hydrocarbon charge - Google Patents

Abstract

Usage: in the petrochemical and chemical industries. In the process control method, the azeotropic dehydration of the hydrocarbon charge regulates the ratio of the steam flow rate into the column boiler and the column feed rate. This ratio is corrected according to the heat content of the feed, the moisture content in the bottom of the column, the difference in temperature between the bottom and top of the column, the bottom and the 13th plate of the column. In addition, the ratio of the consumption of the cube and the power of the column is adjusted with a correction in the level of the cube of the column 1 or

Description

The invention relates to the automation of production processes and can be used in the petrochemical and chemical industries.

Methods are known for regulating the process of azeotropic drying, the disadvantages of which are the low quality of regulation and high energy costs.

The purpose of the invention is to reduce the energy consumption of the process by improving the quality of control.

The drawing shows the implementation scheme of the proposed method

The implementation scheme contains a column 1 of azeotropic dehydration of a boiler 2 columns, a condenser 3, a computing device 4, a steam consumption controller 5 in a boiler with a control valve 6 of steam flow, a wet flow control controller 7 with a control valve 7 of a wet charge, temperature sensor 8 wet

Charge, sensor 9 moisture concentration in the dried charge, sensors 10 of the cube temperature, top 11 of the column, thirteenth plate, 12 columns, regulator 13 of the flow of the dried charge with control valve 14, sensor 15 of the cube of the column.

The method is carried out as follows.

The signals from the sensors of the regulators 5, 7, 13, sensors 8, 10, 11, 12 of the temperature sensor 9 of the moisture concentration, level sensor 15 are fed to the computing device 4

The following values are also entered into the computing device 4: Ati — setting the difference between the temperature of the cube 1K and the temperature of the thirteenth plate w of column 1, ° C; At2 - setting the difference between the temperature of the cube t and the temperature of the top 1B of column 1, ° С; N3ad - task for the value of the level in the cube of the column 1,%,

(L

WITH

4 SP VI Yu O

- set the moisture concentration in the cube of the column 1, wt.%

The VB computing device 4 calculates the following values: The value of the task for the steam consumption into the boiler according to the formula

 Fuj

(one)

where Fn3 is the task for steam consumption, t / h;

Рш current value of charge consumption, t / h;

Ki is the ratio between steam and charge.

The value of the task on the consumption of the cube

where Kz is the proportionality coefficient, and if the condition is satisfied, then,

The percentage of the temperature difference between the cube and the thirteenth plate in the coefficient Ki

(ti3 + Ati) K4,

(6)

where K4 is the proportionality coefficient, and the condition is satisfied if

then

The percentage deviation of moisture content from the task in the coefficient Ki

РкЗ К2-Рш,

(2)

where Rkz - the task of the consumption of the dried mixture, t / h;

K2 is the ratio of the costs of the dried charge and the wet charge.

Setting the value of the coefficient K2;

(Nt-Naad),

(3)

where f 1 is the function of the dependence of K2 on (Ng-Nzad) is determined by the model law of regulation,

Нт is the current one, and Н3ад is the given value for the level of the cube,%, the height of the cube of the column.

(dependence of K2 on (Nt-N3ad) is formed according to model laws of regulation, for example, PI - law)

The heat content of the wet mixture Kj in the coefficient Ki according to the formula

K |

g

steam

(four)

where liwrriv t sleeps - the heat content of the wet charge, kcal / t;

tn is the temperature of the wet mixture, ° C;

Asleep - the heat capacity of the wet mixture, kcal / kg ° C, is taken according to the regulations;

Unap. - steam heat content, Mcal / t.

For temperature differences, AI of the cube and top of the column in the Ki coefficient:

(tB +,

(five)

()

(7)

where fi - the current value of the moisture concentration in the cube of the column, wt.%;

h is the function of az dependence on (psad) determined by the model law of regulation.

The value of the coefficient Ki is determined by the formula

Ki Ai + D2 + Kj + Dz. (S)

The output signals from the computing device 4 are fed to the flow controller 5

Claims (1)

steam in reboiler 2, flow regulator 13 of the dried charge from the bottom of the column 1. Claims so that, in order to reduce energy costs by improving the quality control, measure the level in the column, the flow rate of the dried charge, the temperature of the wet charge, the top and bottom of the column, the temperature on the thirteenth plate of the column, the moisture content in the bottom of the column, the heat content of the wet charge, the temperature difference between the bottom of the cube and the top of the cube and the thirteenth the plates of the column and according to the obtained values correct the ratio of the steam consumption in the column booster and the consumption of the wet charge, determine the ratio of the costs of the dried charge and the wet charge and adjust it to the level in the bottom of the column. Shih.t & five / 0 / pd6 B / Y Return Fractions Ocyu / GWCKJ calch / tu