Automated control system of the reactor unit for the production of terephthalic acid by oxidation of P-xiol

Contents

Introduction

1 Process Description

2 Automation and control of process systems

2.1. Substantiation of the need to improve the existing control, regulation, alarm and interlock system

2.2 Selection and justification of control and control parameters

2.3 Selection and justification of control and control means

2.4 Selection and justification of protective and blocking devices

2.5 Summary Specification Instrument and A

Conclusions

List of sources used

Introduction

Automation of technological processes is a fundamental moment for increasing labor efficiency and improving the quality of products.

The main objectives of process automation are:

improving the efficiency of the production process;

improving the quality of products;

improved security;

improving environmental friendliness;

reduction of raw materials consumption;

increasing the rhythmicity of production;

Improving Cost Effectiveness

To ensure the normal flow of technological processes in modern plants, it is necessary to install numerous control systems of a large number of parameters. Therefore, at the design and operation stages of industrial facilities, the issue of automation is of great importance. Process automation creates an automated process control system (APCS).

The purpose of this course design is to design APCS for terephthalic acid production to ensure the required product quality and maintain the specified process modes. As well as increasing the reliability of the technological system and reducing the proportion of manual labor. For this purpose, the control system is equipped with a set of means for automating control and control parameters.

Process Description

Production of technical terephthalic acid based on reaction of liquid-phase oxidation of paraxylene by air oxygen in medium of reaction solvent is considered.

TFK receiving unit consists of the following units:

- initial mixture preparation unit;

- reactor unit;

- centrifugation and drying unit.

The main tasks of automation of this course project, which determine the efficiency and safety of the TFA production plant, are to control and control the flow rate of raw materials, steam, water, air, their temperature, liquid level values ​ ​ in mass exchangers and tanks, maintain the specified pressure values ​ ​ in devices and flows.

This process is characterized by a small number of controlled and controlled parameters and performance indicators due to the fact that a small number of repeated technological operations are carried out at the plant.

Reactor unit

The initial reaction mixture (paraxylene, acetic acid, cobalt acetate, manganese acetate, tetrabromoethane, antifoam) is heated in heat exchanger T-1 and then supplied at a flow rate of 64 t/h to oxidation reactor P1, where p-xylene is oxidized with air oxygen to form TPA. In the reactor, the temperature is maintained in the range of 185 193℃, the level is from 36 to 49%, the pressure is 0.91.1 MPa.

For oxidation reaction process air is supplied to reactor R-1 by three-stage centrifugal compressor Kr-1 in amount of 33.16 m3/h with temperature from 40 to 60 ℃ and pressure of 1.2 MPa. For uniform distribution of air, the pipeline is equipped with a flow regulator. In the oxidation reactor, it is necessary to control the filling level of the reactor, the increase of which leads to the flooding of the reactor column with liquid, the decrease - to reduce the residence time and, thereby, to reduce the yield of TPA.

Steam-gas mixture (ASG) from the lower part of the reactor is directed to the upper part of the column type, where there are 17 wavy failed trays. The temperature of the column portion of the reactor is maintained within 179189℃. From the top part of the PGS reactor gets to the consecutive system of condensation in X1A,B,C fridges. The pressure on the condenser X1A is displayed, the optimum value of which is 1.05 MPa. The temperature of the vapor gas mixture downstream of the X1C cooler must be monitored to maintain the desired reflux temperature in the oxidation reactor. Condensate and PGS after the X1C fridge get to E-6 phlegm capacity. Part of UC solution from E-6 is supplied to the upper tray for reflux of R-1 reactor through N6 pump equipped with ESD

Automation and control of process systems

2.1 Substantiation of the need to improve the existing control, regulation, alarm and interlocking system

When selecting control and monitoring devices, follow the following provisions:

- instruments must provide the necessary measurement accuracy, be sufficiently sensitive and reliable in operation;

- showing instruments shall have a visual scale;

- Local instruments shall have locations easily accessible for observation of readings;

- the device error must not exceed the available limits in case of change of external conditions, temperature and ambient pressure;

- thermocouple protective sleeves shall be sufficiently strong, designed for these operating conditions;

- measuring and control instruments shall be subject to explosion and fire hazard requirements.

When selecting control and control devices, the properties of control objects and regulators should be taken into account so that the control systems are stable, and the control process itself proceeds qualitatively, without large deviations of the controlled value from the set value.

Conclusions

In this course project, the automation of the reactor unit of the process of production of technical terephthalic acid by oxidation of p-xylene using the example of Polyef OJSC was also selected, automation equipment based on the adopted control and control system was also selected.

During the course project, the following skills were obtained:

- determination of the main controlled, controlled and signaled parameters of TFK production process;

- selection of automation equipment: primary and secondary devices, transducers and actuators;

- execution of automation functional diagram.

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