SU1556734A1 - Device for protection and regulation of the process for producing dimethylformamides - Google Patents

Abstract

The invention relates to devices for the automatic protection and regulation of the technological process for the preparation of dimethylformamide, can be used in the chemical industry and allows to increase the productivity of the process. The device contains measuring tanks 1 and 6, reactor 2, condensation and cleaning unit 3, receiver 4, evaporator 5, flow sensors (D) 9 and 12, pressure D 8 and 15, metering pump 7, Temperature D 13, adder 10, two regulators tori 11 and 16 ratios, setpoint 17, setpoint change unit 19 and actuators 14 and 18. 1 sludge.

Description

The invention relates to devices for the automatic protection and process control of the preparation of dimethylformamide and can be used in the chemical industry.

The purpose of the invention is to increase the productivity of the process.

The drawing shows the flow chart and functional diagram of the device for protecting and regulating the process of producing dimethylformamide.

The scheme contains a mernik 1 methyl formate (MFA), a reactor 2, a block 3 for condensation and purification of dimethylformamide (DMF),

Such a solution is not economical, since stopping the supply of nitrogen only worsens the hydrodynamic regime, but does not constitute a danger of plant failure. Therefore, it is proposed, when stopping the supply of nitrogen to reactor 2, to reduce (about 2 times) the supply of MFA, and therefore, to reduce the supply of DMA vapor. Thus, the installation and in emergency mode continues to work and produce the target Yu product, although in a smaller volume.

It is necessary to maintain the specified ratio of the liquid phase (MFA + recycle) and vapor DMA. However, considering

that the reaction of DMF synthesis is an exothermicressor 4, an evaporator 5, a measuring device 6 is dimethyl, an increase in temperature in the amine (DMA), a dosing pump 7 with a block reactor (before the heat exchange section), a control panel, a nitrogen pressure sensor 8, therefore the ratio indicated The sensor 9 for recycle consumption (gas-liquid must be corrected for the temperature in the MFA phases), the adder 10, the first regulator of the reactor 2.

ratio torus 11, flow sensor 12 In order to provide the required DMA optimal pairs, temperature sensor 13 in the reaction ratio of the liquid and vapor phases of torus 1, actuator 14, you must always have a sufficient pressure sensor 15 in the receiver, the second quantity of DMA vapor that provide the regulator 16 ratios, the setting device 17, the joint operation of the receiver 4 and the actuator 18 for supplying the heat evaporator 5. As is known, the pressure in the receiver to the evaporator 6 and the device 19 25 veR unambiguously determine the number of parameters Neni specifying flow MFA.rov so could put

conventional pressure stabilization circuit. However, in this case, if for one reason or another the specified number of vapors is not enough, you must manually change

The device works as follows.

From the measuring device 1, a dosing pump 7 is fed to the lower plate of the column of the reactor 2 for the synthesis of DMF by an MFA. Liquid

DMA nitrogen is fed to the receiver 4, from where it is 30 task. Therefore, the desired auto-circulates through the evaporator 5, evaporates and in the vapor state from the receiver 4 enters the bottom plate of the DMF synthesis reactor 2.

Nitrogen is also fed under the bottom plate.

ka adjustment of the task depending on the specific consumption of DMA.

If the supply of nitrogen to the reactor 2 is stopped, the nitrogen pressure in the pipeline, as measured by sensor 8, drops. Signal from

unreacted MFA). Due to this recycling, the hydrodynamic situation in reactor 2 is improved, the optimum ratio of liquid and vapor phases is achieved, which has a positive effect on the heat required to stabilize hydrodynamic pressure sensor 8 and enters the device parameters of reactor 2. to 19 and, if this signal is less than specified, the reaction in the liquid, i.e., when there is no nitrogen flow, the phase 19 is fed to the lower plate; reaction 19 gives a command signal to the measuring mixture (recycle) from the unit 6 of the main dose It is used to monitor and purify DMF (basically, pump 7 (decrease) the supply of MFA to the reactor 2. The system for maintaining the MFA / DMA ratio further activates and the supply of DMA decreases accordingly. After the emergency condition is eliminated and the nitrogen supply to the reactor is restored , reaction processes. The reaction mass in the reaction of the protection system is reversed, the vapor-liquid flow comes out of the overheads of the MFA and DMA increases again and its part of the reactor 2 and enters unit 3 the unit goes to the specified condensation and release mode D MFA (block 3).

It consists of a series of apparatus - collections, a circuit for stabilizing the ratio of heat exchangers, an absorbent, etc.). The liquid and vapor phases of the liquid are working as follows: DMF (crude) is fed in 50 in a continuous manner. The signals from the sensor are then consumed at the distillation column for yes MFA (output signal of the control system of the metering pump 7) and the sensor 9 of the flow rate of recycling are fed to the inputs of the adder 10, the output of which is connected to the input of the variable regulator 1 i

cleaning up.

One of the reasons for the occurrence of an emergency in reactor 2 may be the cessation of nitrogen supply to the reactor. In this case, as mentioned above, it is possible to stop the supply of MFA and DMA, the reaction is stopped, the reactor is stopped. However, the process for producing DMF will cease.

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correction by the third parameter.

To the second input "Variable receives a signal from the sensor 12 of the flow rate of vapor DMA. At the input of the Correction Controller 1 1, this solution is not economical, since the cessation of nitrogen supply only worsens the hydrodynamic regime, but does not represent the danger of the installation failing. Therefore, it is proposed, when stopping the supply of nitrogen to reactor 2, to reduce (about 2 times) the supply of MFA, and therefore, to reduce the supply of DMA vapor. Thus, the installation and in emergency mode continues to work and produce the target product, although in a smaller volume.

It is necessary to maintain the specified ratio of the liquid phase (MFA + recycle) and vapor DMA. However, considering

ka adjustment of the task depending on the specific consumption of DMA.

If the supply of nitrogen to the reactor 2 is stopped, the nitrogen pressure in the pipeline, as measured by sensor 8, drops. Signal from

blowing way. The signals from the MPA flow sensor (by tamper signal from the control system of the metering pump 7) and the recycling flow sensor 9 are fed to the inputs of the adder 10, the output of which is connected to the input of the variable controller 1 i

correction by the third parameter.

To the second input "Variable receives a signal from the sensor 12 of the flow rate of the vapor DMA. To the input "Correction of the regulator 1 1 post-formula of the invention

A device for protecting and regulating the process of producing dimethylformamide, containing methyl consumption sensors, forms a signal from temperature sensor 13 in synthesis reactor 2. If for some reason or other the flow rate of the liquid or vapor phase is measured, i.e. the target ratio changes, then the regulator 11 gives the command-, recycling of methyl formate and vapors dimethyl signal at IM 14 executive reactor to the reactor) first regulator according to the mechanism of supplying DMA steam into the reactor, connected by the first input to the date when the temperature in the reactor changes dimethylamine vapor flow sensor, sensor

with respect to the preset, the command signal for changing the supply of DMA to reactor 2 by means of IM 14 is also fulfilled. Thus, the specified optimal ratio is always maintained at the maximum allowable temperature in

reaction.

The maintenance of the required number of DMA vapor is carried out as follows.

nitrogen pressure supplied to the reactor, 10 temperature sensor in the reactor and actuators on the lines of methyl formate and dimethylamine vapor to the reactor and coolant to the dimethylamine evaporator, characterized in that, in order to improve the performance of the process, it is additionally equipped with a sensor and the unit of pressure in the dimethylamine receiver, the device for changing the task of consumption of methyl formate, the second ratio controller and the adder, while the sensors of consumption of methyl formate and recycling of methyl formate 15 and the pressure in multime- dia 20 are connected to inputs of the adder, the output V4 is input to "the variable which is coupled with a second input of the first

the second controller 16 ratios with the corrector-regulator ratios, connected by the tracker in the third parameter. The input to the temperature sensor is input, and the “Variable signal comes from the sensor output to the actuator on

17, and the input “Correction receives 25 dimethylamine vapor supply lines, the sensor signal from the sensor 12 of the DMA vapor flow rate 12. nitrogen pressure is connected through the device

changes in the methyl formate flow rate setting with an actuator on the methyl formate supply line, the dimethyl formate vapor flow sensor is also connected to the first input of the second ratio controller connected to the pressure sensor in the second input by the second input, to the pressure output setpoint in the receiver and the output to to the executive mechanism

If the pressure deviates from the setting (1: 1 ratio) or the DMA vapor flow rate changes, a command signal is run on the IM 18 to supply the coolant to the evaporator 5. As a result, the amount of steam to receiver 4 is changed, providing the required amount of steam fed to the reactor 2

Using this device improves process performance.

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supply of heat carrier to dimethylamine evaporator.

Claims (1)

Invention Formula A device for protecting and regulating the process of producing dimethylformamide, containing sensors for the consumption of methyl formate, recycling of methyl formate and dimethyl amine vapors to the reactor) supply of heat carrier to dimethylamine evaporator.