SU1084036A1 - Method of automatic control of gas separation of pyrolysis products - Google Patents

Abstract

A METHOD FOR AUTOMATIC CONTROL OF THE GAS DIVISION PROCESS OF PYROLYSIS PRODUCTS in an installation that consists of steps for separating light hydrocarbons and isolating heavy hydrocarbons, hydrogenating acetylene compounds, by adjusting the recovery rate of the target product at each step, in order to achieve the goal, in order to achieve a goal, for the purpose of design, the purpose of recovery of the desired product will be reduced. product, reflux in the release of light hydrocarbons, steam in the release of heavy hydrocarbons, the ratio of gas flows during the hydrogenation of acetylene compounds additionally adjusted by a coefficient koefi recovering the desired product gas separation process. (L 19 9 o 00 .4 O CO a g-

Description

The invention relates to methods for the automatic control of a gas separation process and can be applied in the refining, petrochemical, chemical and other industries.

There is a known method of controlling the process of rectification of multicomponent mixtures in series-connected columns by adjusting the quality of the target product in columns tl.

The disadvantage of this method is the lack of control and regulation of the loss of the target component.

The closest to the invention according to the technical essence and the achieved result is the method of automatic control of the gas separation process in an installation consisting of several separation stages by adjusting the extraction coefficient of the target product G 2.

The disadvantage of this method is that the local regulation of the value of the independent variable of each process step of gas separation does not ensure the complete extraction of the target product and, often, does not agree with the global optimality criterion of the whole process.

The purpose of the invention is to minimize the loss of the target product.

The goal is achieved by the fact that according to the method of controlling the N process of gas separation of pyrolysis products in an installation consisting of steps for separating light hydrocarbons and separating heavy hydrocarbons, hydrogenating acetylene compounds by adjusting the recovery rate of the target product at each step, feeding i reflux at the release of light hydrocarbons, the steam supply during the separation of heavy hydrocarbons, the ratio of the flow rates of gas flows during the hydrogenation of acetylene compounds in addition to The correction is performed according to the recovery ratio of the target product of the gas separation process.

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

The process of gas separation of pyrolysis products includes the following stage: the release of light hydrocarbons by the method of low-temperature rectification, the selection

heavy hydrocarbons by the method of low-temperature distillation, hydrogenation of acetylene compounds contained in the ethane-ethylene fraction.

Material balance of each gas separation stage by target component:

g 1 p-g

VX VK.

 at 2 2 G C sft EH ix e ex e

th c g ex ble wer

p4 4

r4

Q5 С

--G

e1he vh vy

d1

OUT VGHE 8Y

3 BX

- the number of fractions

arriving respectively at the separation stage 1, 2, 3, 4, 5,

axs -eAaiS jr ethylene concentration. 4 p5 in the faction, enrolled in the opposite direction, respectively, at the stages of separation 1, 2, 3, 4, 5,

the amount of ethylene in the fraction, respectively, entering the separation steps 1, 2, 3, 4, 5,

the amount of ethylene in the fraction at the exit of the steps is 1, 2, 3, 4, respectively,

c- respectively, if | -

vy vy

The quantity of the fraction, the con centration of ethylene, the amount of ethylene in the fraction at the exit of the separation step is -5. Consequently, the loss of ethylene in each of the separation steps is equal to

- He-Chkha (.1e .., .p5 5 5 where dz.ls, is the loss of ethylene coot5 per stage ST.G |, H separation 1, 2, 3, A separation In the case of ethylene gas separation losses In general, as compared with the norms of the technological regulations, the independent variable value of each process step of gas separation is adjusted according to the gas separation coefficient K, which is determined as follows: The separation of pyrolysis products during gas will be independent in the distribution of light carbohydrates — reflux or refrigerant in reflux. The distillation column torus during the separation of heavy hydrocarbons is the supply of coolant to the distillation column by the hydrogenation of acetylene compounds contained in the ethane-ethylene fraction — hydrogen-containing gas feeds. The gas separation process is performed by a system that includes inlet distillation columns 1, 2, 3 and 4, acetylene hydrocarbon 5 hydrogenation reactor, flow meters 6-16, concentration analyzers of target component 17-22, regulators 23-33, functional blocks 34-45, regulators 46-50. The automatic control method is as follows. The raw material, which is a mixture of hydrocarbons, enters the distillation column 1. The target component of the raw material is ethylene, the concentration of which at the inlet to column 1 is measured by the analyzer 17. Signals, proportional to the consumption of the raw material and the concentration of ethylene in it, enter functional block 34, where the ethylene amount is calculated by the formula (1). J 64 The result of the calculation from block 34 is fed to block 35, which implements a multiplication by a constant factor characterizing the value of the allowable loss of ethylene per cylinder 1. The output signal of block 35 is the reference for controller 23, to which the signal from the block 36, which calculates the amount of ethylene at the outlet of column 1 (entering column 2} according to the formula (2). The error signal of regulator 23 is fed as a correction signal to regulator 24 of the column reflux rate 1. Irrigation flow rate is independent The variable of this technological stage and the control of this variable according to the indicated scheme allows maintaining ethylene losses at a preselected level. At subsequent separation stages, maintaining losses at a preselected level is carried out in a similar way. For column 2, the independent variable is steam consumption into the boiler of the column. The correction signal for the steam flow regulator 26 is formed by blocks 36, 37, 38 and 25 in accordance with formulas (2) and (3). For reactor 5, the independent variable is the ratio of raw hydrogen, supported by regulator 28, the correction signal of which is formed by blocks 38, 39, 40, and 27 in accordance with formulas (3) and (4). For column 3, the independent variable is the flow rate maintained by controller 30. The correction signal for controller 30 is formed by blocks 40, 41, 42, and 29 according to formulas (4) and (5). For the last stage of separation of column 4, the independent variable is the steam consumption in the column booster, supported by regulator 32, the correction signal of which is formed by blocks 42, 43, 44 and 31 in accordance with formulas (5) and (6). The output signal of block 34, proportional to the amount of ethylene at the entrance to the gas separation system, and the output signal of block 44, proportional to the amount of ethylene at the outlet of the gas separation system, are fed to block 45

$ 10840366 of ethylene recovery according to the formula (12). It runs on blocks 35, 37, 39, 41 and 43

The result of the calculation is given in ka-to adjust the coefficients

variable in regulator 33, characterizing the level of permissible

where it is compared with a specified loss value in steps of the ethylene recovery ratio. At 5, the implementation of this method allows the consistency of these signals to increase the extraction of this signal.

The torus 33 forms a signal coming from pyrolysis products by 3 wt.%.

Claims (1)

METHOD FOR AUTOMATIC GAS DISTRIBUTION PROCESS Pyrolysis products in an installation consisting of stages for the isolation of light hydrocarbons and the separation of heavy hydrocarbons, hydrogenation of acetylene compounds by adjusting the recovery coefficient of the target product at each stage, characterized in that, in order to minimize the loss of the target product, reflux is applied during the isolation of light hydrocarbons, steam supply during the separation of heavy hydrocarbons, the ratio of gas flows during the hydrogenation of acetylene compounds is additionally adjusted by the extraction coefficient title product gas separation process.