Functional diagram of automation of polypropylene production process

Contents

Introduction

1. Brief description of the automation object

2. Process Diagram

3. Description of Automation Functional Diagram

Conclusion

List of literature

Application

Introduction

Automation of production processes is one of the most important areas of scientific and technological progress.

In the chemical industry of integrated mechanization and automation, great attention is paid. This is due to the complexity and high speed of technological processes, as well as their sensitivity to violation of the regime, harmful working conditions, explosions and fire hazard of the processed substances, etc.

The limited capacity of the human body is an obstacle to further complication of production. A new stage of machine production is coming - automation, when a person is freed from direct participation in production, and the functions of controlling technological processes, mechanisms, machines are transferred to automatic devices.

Automation leads to an improvement in the main indicators of production efficiency: an increase in the number, an improvement in the quality of products and a decrease in its cost. Productivity increases. The introduction of automatic devices into production also reduces the amount of scrap and waste, and thereby reduces the cost of raw materials.

As mechanization progresses, heavy physical labour is reduced and the number of workers employed directly in production decreases. Automation excludes injuries. Other tasks are assigned to the working personnel: analysis of process control results, preparation of tasks and programs for automatic devices, adjustment of complex automatic devices, etc.

The process automation diagram is included in the working drawings of the automation project and reflects functional connections between the process equipment, instruments and automation tools installed on the technical equipment, near it (in place), on boards and consoles.

Based on the automation scheme, the selection of automation devices and tools is carried out with the compilation of a custom specification.

The coursework includes an automation functional diagram drawing made in A2 format, an explanatory note and a specification for the equipment selected for the automation process implementation.

Brief description of the automation object

Polypropylene is prepared by polymerizing propylene monomer in the presence of organometallic catalysts.

Polypropylene is a colorless crystalline substance, that is, in its natural form translucent, but can be easily colored by the addition of appropriate pigments and paints.

Polypropylene production is fire - and explosive. Propylene in gaseous state forms with air explosive mixtures with explosion limits of 2.2-10, 3 volumes.

High purity propylene is required for polypropylene production. Impurities such as acetylene and sulfurous compounds, oxygen, oxide and carbon dioxide should not exceed one hundredths and one thousandths of a percent.

Polypropylene can be produced in either batch or continuous manner. Continuous polypropylene production processes are economically more advantageous.

The main starting material for the production of many types of products in demand on the market, in particular pipes, packaging, swimming pools, etc., is Polypouplen, a sheet polypropylene produced using extrusion or extrusion technology, the starting material for which is homogeneous polypropylene (PPH) or granulate of the block copolymer polypropylene-ethylene (PPC).

Polypropylene sheets "Multivuplen" are used, in particular, for the production of tanks, swimming pools, storage sumps, accumulators and other sealed containers. At the same time, when conducting installation work using polypropylene sheets, it is necessary to take into account a number of special properties that distinguish them from traditional structural materials.

Polypropylene sheets are easily machined such as cutting, lining, milling, or machining on the same or similar machines as used for wood processing.

The most important advantage of "watering" sheets is their safety for health, since both the starting polymers used for their manufacture and auxiliary additives are environmentally safe.

Description of Automation Functional Diagram

The FSA is the main technical document determining the structure and level of the automation system, equipping the object with instruments, automation and computer equipment. FSA development is carried out on the basis of structural automation diagrams and in accordance with GOST 21.40485.

The functional diagram simplified depicts process equipment, instruments and automation means, as well as main process flows, communication between instruments and automation means.

The automation loops and the hardware on which these loops are implemented will be described below.

Loop 1:

Control of the monomer flow rate at the inlet to the SR with correction for the amount of unreacted monomer.

The unreacted monomer flow rate is measured by a variable pressure drop flowmeter with a standard constriction device. As a standard narrowing device, the standard diaphragm of the chamber DKS 50 is used (pos. 1-1). Pressure drop before and after BC is measured by Metran100DD differential pressure sensor (pos. 1-2), which converts it to a unified 420 mA signal. Then the signal is transmitted to the multiplier by constant coefficient PF1.3.9M1 (pos. 1-3). The signal is transmitted to the registering RP16009 (1-4) device.

The monomer flow rate is also measured by a variable pressure drop flowmeter with a standard constriction device. As a standard narrowing device, the standard diaphragm of the chamber DKS 50 is used (pos. 2-1). Pressure drop before and after BC is measured by Metran100DD differential pressure sensor (pos. 2-2), which transforms it to the unified signal 420 ma then moves on the registering RP16009 device (poses. 2-3) with an input signal of 420 mA, where the flow rate value is recorded. Signals from recording devices are transmitted to BVO2 computational operations unit (pos. 2-4). The unified signal proportional to the current flow value is supplied to the first input of the analog control unit (pos. 2-5). On the second entrance of the regulator the preset value of an expense in the form of a signal of a direct current 420 ma, formed manually by means of the manual RZD22 control point adjustment arrives (poses. 2-6). Signal via manual control unit (pos. 2-7) and non-contact reverse starter (pos. 2-8) gets to the actuator (pos. 2-9) which changes the flow rate of the monomer. Thus, the flow rate of the monomer at the inlet to the CP is adjusted by the amount of unreacted monomer.

Loop 2:

Stabilisation of hydrogen flow rate at the inlet to SR.

Hydrogen flow rate is measured by H54 rotameter (pos. 4-1) with an output signal of 420 mA. The signal is transmitted to the registering RP16009 device (poses. 4-2), and further - to the automatic regulator (pos. 4-3). The regulator generates a pulse signal depending on the setter (pos. 4-4). Signal via manual control unit (pos. 4-5) and non-contact reverse starter (pos. 4-6) gets to the actuator (pos. 4-7), which changes the hydrogen flow rate. Thus, the hydrogen flow rate at the inlet to the SR is stabilized.

Loop 3:

Cascade temperature control in RP reactor, with intermediate coordinate - coolant flow rate.

Temperature in RP reactor is measured using analog temperature converter of Metran276 TSPU (pos. 6-1), which converts it to a unified 420 mA signal. Further the signal is transmitted to the registering device with function of the light alarm system of a limit of a maximum of HL1 RP16009 (poses. 6-2) to record the temperature value and further - to the automatic regulator (pos. 6-3). On the second entrance of the regulator the preset value of temperature in the form of a signal of a direct current 420 ma, formed manually by means of the manual RZD22 control point adjustment arrives (poses. 6-4).

The coolant flow rate is measured by a variable pressure drop flowmeter with a standard constriction device. As a standard narrowing device, the standard diaphragm of the chamber DKS 50 is used (pos. 7-1). Pressure drop before and after BC is measured by Metran100DD differential pressure sensor (pos. 7-2), which converts it to a unified 420 mA signal. From it the unified electric signal is transmitted to the registering RP16009 device (poses. 7-3) with an input signal of 420 mA, where the flow rate value is recorded. The unified signal proportional to the current flow value goes to the automatic regulator (pos. 7-4). The second input of the regulator receives the specified flow rate value Fdd = f (ΔT). Regulator generates pulse signal depending on difference of values. Signal via manual control unit (pos. 7-5) and non-contact reverse starter (pos. 7-6) gets to the actuator (pos. 7-7), which changes the coolant flow rate. Thus, the temperature in the RP reactor is cascaded, with an intermediate coordinate - the coolant flow rate.

Loop 4:

Stabilization of pressure in RP reactor.

Pressure in RP reactor is measured using absolute pressure transmitter Sapphire - 22DA - 2050 (pos. 9-1) with 420 mA output signal and 12 MPa measurement limits. The signal is transmitted to the registering device with function of the alarm system of going beyond a maximum of HL2 RP16009 (poses. 9-2), and further - to the automatic regulator (pos. 9-3). The regulator generates a pulse signal depending on the setter (pos. 9-4). Signal via manual control unit (pos. 9-5) and non-contact reverse starter (pos. 9-6) gets to the actuator (pos. 9-7) which changes the flow rate of the reaction product. Thus, the pressure in the RP reactor is stabilized.

Loop 5:

Control of monomer temperature at RP inlet.

The temperature of the monomer is measured using a copper resistance thermal transducer, type TSM0879 (pos. 111). From it, a non-unified signal in the form of resistance is transmitted to the normalizing converter Sh79 (pos. 112). From the normalizing Sh79 converter the signal 420 ma is transmitted to the registering RP16009 device (poses. 113) with an input signal 420 mA for recording the temperature value. All information about process variables is transmitted to the control control system, where it is displayed on the monitor in the form of a mnemonic diagram.

Loop 6:

Control of solvent flow rate.

The solvent flow rate is measured by a variable pressure drop flowmeter with a standard constrictor. As a standard narrowing device, the standard diaphragm of the chamber DKS 50 is used (pos. 121). Pressure drop before and after BC is measured by Metran100DD differential pressure sensor (pos. 122), which converts it to a unified 420 mA signal. From it the unified electric signal is transmitted to the registering RP16009 device (poses. 123) with an input signal of 420 mA, where a solvent flow rate value is recorded. All information about process variables is transmitted to the control control system, where it is displayed on the monitor in the form of a mnemonic diagram.

Loop 7:

Control of catalyst flow rate.

The catalyst flow rate is measured using the electromagnetic flowmeter IPRE132. The primary flow converter is PPR32 (pos. 131). The secondary converter is the IPP2 device (pos. 132), which converts it to a unified 420 mA signal. The signal is transmitted to the recording device PP16009 (133) where the catalyst flow rate is recorded. All information about process variables is transmitted to the control control system, where it is displayed on the monitor in the form of a mnemonic diagram.

Loop 8:

Start/stop of RP reactor agitator engine by operator both on-site and from control panel or workstation.

Manual control unit (pos. HS143) installed on the operator console performs the functions of switching from automatic to manual mode. Manual setter (pos. H141) installed in situ allow the operator to control the agitator engine in situ.

Loop 9:

Protection for emergency situation - temperature rise in RP reactor above critical value.

If the upper temperature limit in the reactor is exceeded, the HL3 light alarm and temperature relay (pos. 151) closes the hydrogen supply valves (pos. 153), catalyst (pos. 155) and solvent (pos. 157).

Control of all automation tools is duplicated from the microprocessor controller (IPC) and workstation (computer). The workstation is equipped with a monitor for providing information to the operator and a keyboard, by means of which the operator makes his adjustments to the process control

Conclusion

The result of this work is a developed functional diagram of automation of polypropylene production. Control, regulation, stabilization and signalling of the main process parameters specified by the task are provided. Automation tools are selected to control and control the selected parameters. When selecting devices and automation means, the operating conditions of devices and systems, limit values ​ ​ and the range of changes in process parameters, requirements for accuracy of control and regulation, speed, reliability, etc., were taken into account. The FSA developed is made on the A2 format drawing, the custom equipment specification made according to the Gosstandart is attached to the diagram.

Automation of this process leads to the improvement of the main indicators of production efficiency. The introduction of automatic devices ensures high quality of products, reduction of scrap and waste, reduction of raw materials and energy consumption, reduction of the number of main workers, reduction of capital costs for building construction.

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