SU1555323A1 - Method of controlling process of propylene hydroformylation in unit - Google Patents

Abstract

The invention relates to methods for controlling chemical processes, in particular to methods for controlling the process of propylene hydroformylation, can be used in the chemical industry and allows reducing the specific consumption of propylene and increasing the yield of n-butyraldehyde. The process of hydroformylation of propylene was proposed to be carried out by stabilizing the temperature in the reaction zone and the ratio of initial propylene and synthesis gas fed to the reactor, and the process was controlled by stabilizing the concentration of catalyst at the reactor inlet and changing the ratio of hydrogen and carbon monoxide — the components of synthesis gas. entering the reactor, depending on the concentration of carbon monoxide in the gases leaving the high pressure separator. 1 il.

Description

The invention relates to the field of controlling chemical processes and can be used in the chemical industry in the process of hydroformylation of propylene.

The purpose of the invention is to reduce the specific consumption of propylene and increase productivity in H-oil

aldehyde.

The drawing shows a schematic diagram of the automatic control of the process of propylene hydroformylation in a cascade of two factors that implements the proposed method.

The reaction unit includes two series-connected reactors 1

and 2 propylene hydroformylation, with heat removal, high pressure separator 3, remote heat exchangers 4 and 5 for cooling the refrigerant, and circulation pumps 6 and 7, ensuring the supply of the refrigerant to the reactors. The temperature in the reactors, measured by sensors 8 and 9, is controlled by regulators 10 and 11 by influencing the valves 12 and 13 of the refrigerant supply to the external heat exchangers and the valves 14 and 15 bypassing the open lines.

The costs of propylene8 of the catalyst solution, synthesis gas, retract gas and converted gas are measured by sensors 16-20, respectively. Sossl

ate

SL

with

ND

WITH

Tava catalyst solution, inert and converted gases, and carbon monoxide concentration at the outlet of the high pressure separator are measured with analyzers (sensors) 21-24, respectively.

The control system also contains a unit 25 for calculating the concentration of catalyst at the inlet of the reactor 1, a regulator 26 and a valve 27 for maintaining a predetermined value of the concentration of catalyst in the stream, a unit 28 for controlling the ratio of the flow rates of propylene and synthesis gas supplied through the valve 29, unit 30 for calculating the current value of the synthesis gas composition (hydrogen: carbon monoxide ratio) supplied to mixing with propylene, the regulator 31 and the valve 32 to maintain the required ratio of synthesis gas components by changing the flow converter gas into separation unit 33 by controlling the flow through valve 32.

The control method is carried out as follows.

The signals from sensors 16, 17 and 21 of propylene consumption, catalyst solution and catalyst concentration are fed to block 25, in which the current value of catalyst concentration at the reactor inlet is calculated, the set value of which is maintained by regulator 26 by changing the flow rate of the catalyst solution to the reactor 27.

The calculation of the current concentration value in block 25 is carried out according to the following algorithm:

g - it

QKT- Co

where St - the current value of the concentration of catalyst at the inlet to the reactor, wt.%;

C0 is the concentration of the catalyst in the catalyst solution,

Lkg qn

- the cost of the catalyst solution and propylene, respectively, kg / h. The signals from the sensors 16 and 18 of the propylene and synthesis gas consumption flow to the input of the initial components ratio control unit 28, which acts on the synthesis gas supply valve 29, maintaining the ratio

5 Q 5

0

0

propylene: synthesis gas at a given level.

The composition of the original synthesis gas is formed from the converted gas consisting of carbon monoxide AND hydrogen supplied to the system in the form of two mutually regulated streams, the first (smaller) stream being mixed without changing the composition, and the second enters into separation unit 33 ( to separate the main part of the hydrogen), from where, in the form of a retreat gas, it is mixed with the first stream. The signals from sensors 19 and 20 of the return and converted gas consumption, sensors 22 and 23 of the composition of the return and convertible gas, as well as sensor 24 of carbon monoxide and high-pressure separator 3 gas are fed to block 30, in which the current value of composition CT is calculated gas (hydrogen: carbon monoxide ratio), adjusted by the deviation of the value of the concentration of carbon monoxide in the high pressure separator 3 from the specified concentration value, and then the correction value Q is adjusted for setting the regulator 31, the ratio of the converted gas flows to the valve 32, according to the following algorithms:

Kg K0-K, - D;

R -v -v U L O T

Q Q.X Qjp, JL 4 t Y 0 „g X,

X,

 i

where CT is the current value of the composition of the synthesis gas (the ratio of hydrogen: carbon monoxide),. corrected for the deviation of the value of the concentration of carbon monoxide in the gases of the separator 3 from a given value;

To - the specified value of the composition of the synthesis gas (the ratio of hydrogen: carbon monoxide); D is the amount of deviation of the carbon monoxide concentration in the separator 3 from the predetermined value, mole fraction;

Xfl, Xt - the value of the concentration of carbon monoxide in the separator 3, respectively, given and current, mole fraction;

QKP is the amount of the correction signal for setting the regulator 31 to the regulator - valve 32;

return and converted gas costs respectively

V

ten

15

X is the concentration of hydrogen and carbon monoxide, respectively, in the converted gas, vol.%; Xj is the concentration of hydrogen in

retour gas, vol.%; Using the proposed method of automatically controlling the process of hydroformylation of propylene, compared with the known method, the following advantages are obtained: to increase the conversion of 20 ropylen to the target aldehydes by changing the composition of the original synthesis gas while maintaining the ratio of the raw components of propylene: synthesis gas, and also to increase the yield of n-oil 25 aldehyde due to a change in the ratio of isomers towards an increase in the fraction of the isomer of normal structure, due to the more accurate zirovkoy components of synthesis gas into reaction zone zo tion.

Claims (1)

Claims of Invention A method for controlling a process of hydroformylation of propylene in a plant comprising: reactors and separator, including ten 53236 stabilization of the temperature in the reaction mixture, the concentration of the catalyst at the inlet of the first reactor, the change in the supply of catalyst to it, the regulation of the supply of synthetic gas and propylene to the first reactor, the measurement of concentrate and carbon monoxide at the separator outlet and the consumption of propylene and the first reactor, five 0 5 o five the consumption of propylene and the increase in productivity of n-butyric aldehyde, additionally measure the concentrations of hydrogen and carbon monoxide in the converted gas and its consumption, the concentration of hydrogen in the retreat gas and its consumption, calculate the ratio of the concentrations of hydrogen and carbon monoxide in synthesis gas, oxide carbon and hydrogen in the converted gas, hydrogen in the return and converted gases, and the ratio of the costs of the return and converted gases and change the supply of the converted gas to the first reactor is directly proportional to The ratio of the concentrations of hydrogen and carbon monoxide in the synthesis gas and the oxides of carbon and hydrogen in the converted gas and inversely is proportional to the ratio of the return and converted gas consumption and the ratio of the concentration of hydrogen in the return and converted gases and regulate the supply of synthesis gas to the first reactor depending on the consumption of propylene in it.