SU1214127A1 - Method of automatic controlling of fractionation - Google Patents

Description

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The invention relates to methods for controlling complex technological processes in the chemical, oil refining industry and can be used in the automation of processes occurring in a stationary catalyst bed with subsequent fractionation of the resulting catalyzate.

The purpose of the invention is to increase the selection and improve the quality of the target product due to increased regulation accuracy.

The nature of the processes of sulfur compounds flowing in the reactor, the chemistry of the numerous paraffinic and naphthenic isomerization reactions occurring simultaneously, the formation of unsaturated hydrocarbons, etc., depends on the conditions in the reactor: pressure, temperature of the stationary catalyst bed and its quality, on the quality and quantity of sgr and hydrogen-containing gas, which determines the quality of the hydrogenate, which is the raw material for the fractionation column, in which it is divided into separate fractions ii.

One of the main indicators of the quality of the hydrogenate is the content of light fractions in it, which can be determined by the following relationship:

Q, “a„ + a, Tr + a

, Pp + a, F, -ba, Fg

+ asA, + 6Qc + a, Qeer

(one)

de Tr

Pr,

 8cr

QC Q

WASH

-the temperature in the reactor;

- pressure in the reactor;

-quality of raw materials entering the reactor (density, fractional composition);

-the quality of the hydrogen-containing gas (hydrogen content);

-the cost of sf;

- consumption of hydrogenous gas;

- catalyst activity;

to -,

where hell is the initial activity of the catalyst; - catalyst time;

but"

K is the coefficient of decrease in the activity of the catalyst; and (, -a are the coefficients determined by the processing of statistical data obtained in the course of the experimental work and refined during the operation.

The main disturbing effect on the distillation column is the quality of the feedstock, namely the content of light fractions in it, which depends on the mode of the reactor block.

There is a definite relationship between the flashpoint of diesel fuel, the mode of the column and the quality of the raw materials entering the column, or the mode of the reactor block, i.e.

t

8c P

(Q.

.

 VC

 IR

R.).

25

or the transition to a more detailed record, taking into account equation (1),

tBcH., t, + b, t ,, + b, P, + b., TpH- + b, R 4., F ,, + NQc- b, Qaor (2)

five

0

five

0

five

VC

- temperature of the bottom of the column

-the temperature of the top of the column;

P i - pressure in the column; the corresponding equation coefficients

regression of the binding value of the quality indicator with regime parameters.

The drawing shows a diagram of the implementation of the method.

The method is carried out as follows.

The raw material mixed with the hydrogen-containing gas, after being heated in the furnace 1, enters the reactor 2, where the hydrodesulfurization reaction takes place, after which the reaction products enter through the heat exchangers 3 into the fractionation column 3. The light fraction through the heat exchanger 5 and the separator 6 is removed from the column, part the bottom product through the furnace 7 is fed to the bottom of the column, the balance of the amount of diesel fuel is removed from the installation.

The quality and consumption of raw materials and hydrogen-containing gas are measured by sensors 8-11, temperature and pressure in the reactor by sensors 12 and 13, temperature and pressure of the top and bottom temperature by sensors 14-16, catalyst activity is calculated based on the initial activity of the catalyst Au the installation time of the computing device 17.

The content of light fractions in the bottom product depends on the temperature of the top, bottom, pressure in the column, on the operating variables of the reactor block, measured by sensors 8-13, and catalyst activity. The value of the quality index of the target product (for example, flash point) is predicted from the signals of sensors e-16 by the computing device 17 according to equation (2).

If the temperature of the diesel fuel flashpoint deviates from the target value, the new values of the top and bottom of the column are calculated, which

Editor V. Kovtun Order 815/7

Compiled by T. Chulkova

Tehred A. Babinets Proofreader M, Samborska

Circulation 663

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VNIIPI State Committee of the USSR

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Branch PPP Patent, g. Uzhgorod, st. Project, 4

214127

provide a product of a given quality. The calculated temperatures of the top and bottom of the column come in the form of a task to the control systems 5, ensuring that these values are maintained at a given level by changing the supply of acute irrigation by influencing valve 18 and changing the temperature of the lower 10 circulating irrigation by influencing valve 19.

The values of the current controlled variables (the temperatures of the top and bottom of the columns O enter the computational) 5 device 17 periodically one time.

at 2 s, the task of changing the temperature of the top and bottom of the column is calculated once every 3 minutes.

The change of the task is made in steps according to the proportional law for the amount chosen in each particular case, based on the inadmissibility of introducing sharp disturbances into the control system.

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Claims (1)

METHOD FOR AUTOMATIC CONTROL OF THE REFINITION PROCESS at a hydrotreatment unit for oil products, including measuring the temperatures of the top and bottom of the column, the consumption of hydrogen-containing gas and raw materials supplied to the reactor, the temperature of the catalyst layer, depending on which the flow of sharp irrigation and fuel to the column is changed, characterized in that that, in order to increase the selection and improve the quality of the target product by increasing the accuracy of regulation, we additionally measure the quality of the hydrogen-containing gas and raw materials, the activity of catalyst, the pressure in the reactor, according to the measured parameters, taking into account the corresponding coefficients, determine _the predicted value of the flash temperature, compare it with the set value and, depending on the magnitude of the mismatch, regulate the temperature of the top and bottom of the column. > . eleven