SU1301826A1 - Method for controlling process of hydrocarbon dehydrogeneration - Google Patents

Abstract

The invention relates to the automation of cyclic chemical processes, in particular the production of isoprene and divinyl, can be used in the chemical and petrochemical industries and reduces the unit costs of raw materials and energy resources. The method is implemented by the SAR, which includes a steam consumption stabilization circuit in the furnace (P) 5 - controller (P) 8, air consumption stabilization circuit - P 9, raw material consumption control loop in P 5 - sensor (D) 7, P 6, control loop pressure at the outlet of the catalyst bed, respectively, of reactors 1, 2 - D 10, 11, pressure differential block 13, pressure differential Р 14, valve 12 on the regeneration gas line, corrective Р 15 associated with Р 6 and 14, program block 4, acting on the valves 3 supply of raw materials and air into the reactors 1, 2. 1 Il. (O (L leiuitiiftif yd Zadvitkl with from the burrow "Closed Partial Atmosphere

Description

113

The invention concerns the automation of cyclic reaction processes of chemical-technological production, in particular, the production of isoprene and divinyl, and can be used in the chemical, petrochemical and other industries.

The aim of the invention is to reduce the specific consumption of raw materials and energy resources.

The drawing shows a circuit for carrying out the proposed method.

The dehydrogenation process is carried out in reactors 1 and 2 with a fixed catalyst bed, switched by acting on gate valves 3 using software block 4 alternately from contact to regeneration and back (in the diagram, reactor 1 is shown in contact mode and reactor 2 is regeneration). The raw material is fed to the reactor after overheating in the furnace 5. Water vapor, superheated in furnace 5, is distributed between reactors 1 and 2: a part is supplied for contacting, and the rest is for regeneration. The regeneration gas after condensation of water vapor is discharged into the atmosphere, and the contact gas is directed to the compression and separation unit.

The process control system contains a raw material consumption regulator 6 with a sensor 7, a regulator 8 of total steam consumption for contacting and regeneration, an air consumption regulator 9 for regeneration, pressure sensors 10 and 11 at the outlet of the catalyst bed of reactor 1 and reactor 2, respectively, the valve 12 on the regeneration gas line, the differential pressure determination unit 13, the differential pressure control unit 14 and the correction unit 15.

The method is carried out as follows.

Using regulators 6 and 8, they regulate the consumption of raw materials and steam, respectively, fed through furnace 5 to reactors 1 and 2. By means of regulator 9, regulate the flow of air for regeneration.

Using block 13, taking into account the information from block 4, the differential between the pressure at the outlet of the catalyst bed in the contact mode and the pressure at the outlet from the bed is determined.

2

in regeneration mode. 1 this differential is

 R

1 TO

- R.

IP

(one)

where r

1 TO

the pressure value measured by sensor 10 is in the middle of the contact interval of the i-ro cycle; the pressure value measured by sensor 10 is in the middle of the regeneration interval of the i-ro cycle. Similarly for reactor 2:

1R p.

0

2K

LR 2P

 Р Р.

2P

(2)

where r. ; P corresponding to pressure.

measured with sensor 1 1.

With the help of the regulator, the valve 12 is, pi-law, and the value of

14 influences for example

thirty

25

. rr

3 ().

LO.E.

(3)

35

40

The value of task P is adjusted using block 15, depending on the consumption of raw material G, measured by sensor 7, according to the empirical dependence

LR f (G). (4) Despite the fact that reactors 1 and 2 operate in a symmetrical pattern,

12

LR values, - and DR. in practice are not always equal. The averaged value of the differential in the expression (3) is used to take into account the asymmetry in the operation of the reactors.

Technical implementation of blocks 13-15

microcomputers are implemented.

for example, using

45

50

55

The steam distribution between the reactors, i.e. for contacting and regeneration, in the process of dehydrogenation, it is not directly controlled and not regulated due to the high temperature of the steam (about). This distribution is determined by the ratio of the resistances of the contact gas lines and the regeneration gas.

The pressure drop at the outlet of the catalyst bed in the contact mode and the regeneration mode indirectly characterizes the distribution of steam between the reactors. Therefore, this method

313

ensures the maintenance of a given vapor distribution under perturbation conditions, i.e. at change of conditions of condensation, compression, at change of ambient temperature, etc. Stable steam supply for contacting and regeneration eliminates catalyst overheating and excessive coking, ensures stable

the yield of the target product at the pro- faction, characterized in

Launched raw material eliminates the need for excessive steam supply to the kiln, caused by the danger of under-diluting the raw material when contacted by the Scientific Research Institute.

The use of this method allows to reduce the consumption ratios for the main raw material (isopentane) by 0.6 and a couple by 0.2 rel.%. 20

Editor S.Pekar Order 1190/25

Compiled by G. Ogadanov

Tehred A. Kravchuk Proofreader S. Shekmar

Circulation 372. Subscription VNIIPI USSR State Committee

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

Production and printing company, Uzhgorod, Projecto st., 4

Claims (1)

Claims The method of controlling the process of dehydrating hydrocarbons, carried out in a two-reactor cyclic system, by controlling the flow rate for contacting, the air consumption for regeneration, the total consumption of steam for contacting and regeneration, and the input of gases for regeneration, in order to reduce the specific consumption of raw materials and energy resources additionally, the gas pressure at the outlet of the catalyst bed is measured in both reactors in the contacting and regeneration modes, the differential pressure measured is determined Nij and regulate output regeneration gas depending on the pressure difference with the correction of the feed flow.