SU1491869A1 - Method of controlling cyclic process of dehydration - Google Patents

Abstract

The invention relates to the field of automating reaction processes involving the periodic regeneration of a catalyst, in particular, the process of dehydrogenating n-butylenes to divinyl, and can be used in the chemical and petrochemical industries. The aim of the invention is to increase the yield of divinyl. The method involves adjusting the furnace temperature by changing the supply of fuel gas to the furnace, the temperature of the mixture at the reactor outlet by changing the supply of saturated steam to the reactor with a correction for the concentration of divinyl in the contact gas, during each contact interval, the control of the supply of raw materials is directly proportional to the concentration of divinyl in the contact gas, the supply of water to the irrigation of the scrubber is directly proportional to the supply of raw materials, and at the beginning of each regeneration interval the air supply is proportional to cf. days divinyl formulation in the preceding interval and further contacting during regeneration interval regulate the air supply depending on the temperature profile in the reactor and its rate of change. 1 il.

Description

The invention relates to the automation of reaction processes involving the periodic regeneration of a catalyst, in particular the process of dehydrogenating n-butylenes to divinyl, and can be used in chemical and petrochemical industry.

The aim of the invention is to increase the yield of divinyl.

The drawing shows a schematic diagram of a control system implementing this method.

The dehydrogenation process is carried out at a temperature in the order in reactors 1 with three fixed catalyst beds, and the dehydrogenation (contact) intervals alternate with catalyst regeneration intervals by periodically switching valves 2 with the aid of the controller 3. Stef is fed into the reactor in a mixture with steam after superheating furnaces 4. The gas mixture is removed from the reactor either to the atmosphere (if regeneration is proceeding) or after cooling

;about

00 9d CO

Deni in waste heat boiler 5 and scrubber 6 - for cleaning (if contacting is in progress).

The process control system includes a steam consumption controller 7 in the furnace, a raw material consumption controller 8 with a sensor 9, a regeneration air consumption controller 10, a scrubber irrigation water consumption controller 11, a furnace temperature controller 12, a temperature controller 13 at the entrance to the reactor with a sensor 14 and a valve 15 on the supply line of saturated steam into the reactor, an analyzer (chromatograph) 16 of the composition of the contact gas and sensors 17 of temperature in the catalyst beds. The diagram also shows the functional blocks implemented in the control computer 18: the scrubber irrigation water correction unit 19, the feed supply correction unit 20, the reactor inlet temperature correction unit 21 and the regeneration air supply correction block 22

The method is carried out as follows.

Using the controller 3 by closing -opening - the valves 2 periodically switch the reactor 1 from contact to regeneration and back. Using regulators 7, 8, 10, 11, regulate the flow of steam to the furnace 4, raw materials for contacting, air for regeneration and water for irrigation of the scrubber 6, respectively. Using controller 12, regulate the temperature in furnace 4, which determines the degree of overheating of the raw material and a couple. Using the controller 13 for measuring from the sensor 14, the influence on the valve 15 regulates the temperature at the inlet to the reactor 1.

With the help of the functional unit 20, implemented in the control room 18, the task is adjusted to the controller 8, for example, according to the following law:

, gs1A

G:

to, with

Liv

where G is the base value of the load on the contact interval, using block 21, adjust

setting the controller to 13, for example, by

following law:

g

at

Ph-K, C

Div

where T is the base temperature at the inlet to the reactor for the contact interval.

The concentration of divinyl in the contact gas is determined by information from the analyzer 16, and the coefficients K ,, Kj are set constant (in the simplest case) or determined by a mathematical model of the dehydrogenation process.

Using block 19, the task to the controller 11 is adjusted, for example, according to the following law:

Where

P p

ox

+ K

 h) r with I is the base value of the node supply for scrubber irrigation;

raw material metering

using sensor 9}

coefficient. Using block 22, at the beginning of each regeneration interval, the basic value of the air flow for this interval is determined:

t to

GC K,

 605D

 -f (G /, X

where tj, is the duration of the last contact interval, x is the current output of divinyl on

the missing feedstock in the last contact interval, as determined with the help of the analyzer 16, vol is the coefficient. During the regeneration interval, the value of o is determined. for each catalyst layer (in this example, in the reactor 3 layers):

R. (,

where T., Tj.

accordingly, the temperature in the J-M layer and its rate of change, determined by measurement from sensors 17; maximum permissible temperature of the catalyst, Pj - coefficients. The setting of controller 10 is determined as follows:

mlks

five

G

Oa

G

/ wakC

Where

 g 1 L

Vol, J i t L) - L J J 1, if at least one of the conditions is fulfilled

U-Nj L7 (: Ь2,3),

.o, in the remaining cases.

Raw material

air

Masichenng

pezeffepoe {i / u

8Lg

Claims (1)

Claim A method for controlling cyclical process of dehydrogenation of n-butilepov a divinyl modes contacting and regeneration comprising regulirova869 ⁶ of oven temperature regime change of fuel gas in a furnace, temperature of the mixture at the inlet of the reactor change supplying saturated steam into the reactor and regulating the feed and steam in the oven, air into the reactor and water for irrigation of the scrubber, characterized in that, in order to q increase the yield of divinyl, the concentration of divinyl in the contact gas at the outlet of the reactor and the temperature are additionally measured the profile in the reactor over the catalyst layers, during each contacting interval, the average production of divinyl is determined by the consumption of raw materials and the concentration of divinyl in the contact gas, the supply of raw materials is directly proportional to the θ concentration of divinyl in the contact gas and the water supply for scrubber irrigation is directly proportional to the supply of raw materials, adjust the temperature of the mixture at the inlet of the reactor inversely with the concentration of divinyl in the contact gas; at the beginning of each regeneration interval, regulate the air supply ortsionalno average product divinyl previous interθ shaft contacting and more during the interval of regeneration air supply is controlled by the 'temperature profile in the reactor and its rate of change.