SU889650A1 - Device for automatic control of ethylbenzene two-step dehydrogenation process - Google Patents

Description

(54) DEVICE FOR AUTOMATIC CONTROL OF THE PROCESS, TWO-STAGE DEGYDRATION

The invention relates to devices for the automatic control of technological processes and can be used in the chemical and petrochemical industry in automating the production of styrene.

A known system for automatically controlling a two-stage ethylbenzene dehydrogenation reactor containing concentrator on the pipeline after the first and second stages of the reactor, regulators and valves for supplying fuel to the furnace, averaging unit and adder P.

It is also known a device for automatically controlling the process of hydrocarbons dehydrogenation, which contains control circuits for the consumption of raw materials and steam in a furnace, each of which contains a series-connected flow sensor, a regulator and a valve, control circuits for steam temperature at the outlet of the furnace chambers, each of which consists of ETHYLBENZENE.

sensors connected in series, temperature, regulator and valve for supplying fuel to the furnace, fuel pressure sensor and raw material consumption setting unit 2.

However, the known devices do not provide for programmed correction of the temperature at the outlet of the furnace and steam consumption when changing the consumption of raw materials. This leads to significant cobalt parameters of the process and reduces the productivity of the reactor.

The aim of the invention is to increase the productivity of the reactor ..

15

The goal is achieved by the fact that the device additionally contains software blocks for steam flow rate and temperature, the first and second delay blocks and the correction block, with

Claims (2)

30 this output of the raw material flow setting unit is connected in parallel to the inputs of the first lag unit, the program blocks of the steam flow rate and the first 3 inputs of the steam temperature program blocks, the second inputs of which are connected to the fuel pressure sensor through the correction unit, the outputs of the steam temperature program blocks are connected to their control tori, the output of the program block of steam consumption through the second block of delay is connected to the regulator of steam consumption, and the output of the first block of delay is connected with the regulator of the feedstock. The drawing shows the device implementation scheme. The dehydrogenation reactor has two stages 1 and 2. The temperature required at each stage is maintained by means of water vapor, which is superheated in a furnace having two chambers 3 and 4. The device contains a sensor 5, a regulator 6 and a valve 7 for raw material consumption in Parachute, sensor 8, controller 9 and valve 10 for steam supply to the furnace, sensors P and 12, and regulators 13 and 14 of steam temperature at the outlet of chambers 3 and 4 of the furnace, valves 15 and 16 for supplying fuel to the furnace, unit 7 task of raw material consumption, program PIOK 18 steam consumption, program blocks 19 and 20 of steam temperature, first and second second blocks 21 and 22 zapazdshani, the correction unit 23 and the fuel pressure sensor 24. . The device works as follows. Regulators 6 and 9 maintain the desired flow rates of the reaction mixture into the dehydrogenation reactor and steam into the coils of the superheater. Regulators 13 and 14 of superheated steam temperature stabilize at a given level the temperature at the outlet of the coils of chambers 3 and 4 of the furnace, measured by sensors 11 and 12, by acting on valves 15 and 16. Block 17 sets the output flow rate the signal is proportional to the current setpoint value of the flow rate of the reaction mixture in the reactor F-. . When the given flow rate F is changed, program blocks 18, 19 and 20 change the settings of the steam flow regulator and the steam temperature regulators at the output of the coils of chambers 3 and 4 hb and t, a, b, a, b are coefficients determined by Experimentally for a specific reactor-furnace complex. The lag blocks 21 and 22 enclose the delay in changing the assignment to streets 6 and 9 according to the law | W -: # i (i-), t is the current time; c, g, for regulator 6; t-t for regulator 9; t. and To are determined experimentally for a particular installation; the value of the task arriving at the i-th lag block; the value of the task exiting the i-th lag block. The correction unit 23 amends the setting of the temperature controllers 14, the pressure P (fuel gas sensor, according to the law) (. 3,. E and SW.-DP Ji-4o; i} 100) and-e 2 / previous. steam temperature torors; t is the current time, oL, coefficients determined experimentally for a particular installation. The use of the proposed device allows us to reduce the consumption of raw materials (ethylbenzene) to 1.18 tons / ton. The invention The device for the automatic process of two-stage dehydration of ethylbenzene, coagulating control loops and steam into the furnace, each of which contains successively flow rate sensors, valve controllers, control circuits for adjusting the steam theme at the outlet of the chambers, each of which consists of sequentially connected perimeter sensors, regulator and valve of fuel start to the furnace, fuel pressure sensor and, block for setting the flow rate, from. Characterized by the fact that, in order to increase reactor productivity, it additionally contains steam flow and temperature program blocks, the first and second delay blocks, and a correction block, while the output of the raw flow task block is connected in parallel to the inputs of the first delay block, steam flow program blocks and to the first inputs of program blocks of steam temperature, the second inputs of which through the correction block are connected to the fuel pressure sensor, the outputs of the program blocks of steam temperature 4 are connected with their regulator The output of the software steam consumption unit through the second lag unit is connected to the steam flow controller, and the output of the first delay unit is connected to the raw material flow controller. Sources of information taken into account in the examination 1. USSR author's certificate number 712410, cl. From 07 to 15/10, 1978. 2. USSR author's certificate number 473705, cl. C 07 S 5/18, 1973.