PSA gas collection of acetic acid branch of a Chem

Overview of PCS7

project of pressure swing adsorption gas collection device of haimou Chemical Co., Ltd. (acetic acid branch):

-- a Chemical Co., Ltd. in Shanghai is the largest chlor alkali enterprise in China, with its comprehensive strength ranking the third in the national chemical industry, and the first in the chlor alkali industry. The change of resistance is transformed into strong change of voltage or current through Wheatstone bridge. In the fierce bidding competition, Shanghai Siemens Industrial Automation Co., Ltd. finally won the bid and was responsible for establishing automatic control systems in the polymerization plant and drying plant to ensure the design scale of an annual output of 3000t PVC products of a Chemical Co., Ltd. in Shanghai. The scope of work undertaken by Shanghai Siemens Industrial Automation Co., Ltd. includes:

hardware supply, project management, software design, system integration, on-site installation and commissioning, customer training, etc

--- in the PVC pilot plant project of a chemical plant in Shanghai, Shanghai Siemens Industrial Automation Co., Ltd. adopted the most advanced PCS7 Process Control System of Siemens as the hardware platform of the automation system of the whole plant. The whole system consists of one 417h (including De'an and intrinsic safety modules), two operator workstations (one of which can be used as an engineer station), and PROFIBUS PA instruments. The powerful functions of PCS7, such as batch processing, event driving, redundancy, PROFIBUS PA, and intrinsically safe remote i/o modules, have been successfully used.

process introduction:

---s-pvc (polyvinyl chloride) 7m3 pilot project is a pilot plant in the technical center and National Central Laboratory of a Chemical Co., Ltd. in Shanghai, which undertakes the formula test of different grades of polyvinyl chloride. Its process flow is mainly divided into six parts: chemical preparation, polymerization recovery, stripping and drying, product transportation and utilities. Among them, the preparation, polymerization and recovery of chemicals constitute the whole batch control process, and the whole process reaction of the S-P device to protect VC resin is carried out in a 7m3 polymerization kettle

control object:

--- each batch production process of PVC has 22 processes. The automatic control of these processes is completed by the sequence control (SFC) in PCS7 System. The sequence control program has 35 units, each process corresponds to one or more control program units, and the detailed control steps of each unit are described according to different sequence diagrams

control points:

--- the polymerization plant is an explosion-proof zone 2. The polymerization process implements batch sequence control. Through high-precision dynamic temperature control, how to select a suitable electronic change experimental machine for the PVC main clutch to do the experiment? The clutch should select the electronic type suitable for the specification and model according to the tested model, and change the key quality index of the experimental machine - the control of polymerization degree. Safety inspection and emergency handling are set up in batch control. Fieldbus equipment is used in the drying plant

--- heating up, polymerization in the polymerization kettle, and stripping recovery in the later stage are more complex process control in the batch process. There are many control methods in this process. PD, PID, layering, ratio and other controls occupy more components in many complex loop controls, Using the strong function block characteristics of CFC and the flexible sequence control of SFC, many control requirements in the process control are met

system configuration:

--- the system is configured with two operation stations, and its main functions include:

process data display and operation

system and process alarm

real time and historical trend display and recording

batch setting, operation and recording

process equipment management

configuration and debugging

--- due to the pre installed system software, the maintenance engineer can log in at any time to switch the operation station to the engineer station state, And can be modified

--- as a typical batch production process, in the production process of a batch of products, if the production is interrupted due to the failure of the control system, it will cause great losses. We choose the fully redundant controller with as417h, so as to ensure the mean time between failures of 20 years. In addition, its integrated 4mram, coupled with another expanded 4mram, rich memory resources meet the large but unstable requirements of batch control on system resources. At the same time, the s components configured by the system and the et200m with active backplane bus have plug-in functions

--- the system adopts a 4-level network system:

Ethernet - data transmission of batch control server and operation station

Industrial Ethernet - system bus, data transmission between operation station and controller

PROFIBUS-DP - system i/o bus, Data transmission between controller and i/o station

profibus-pa - data transmission between system and PA intelligent instrument

--- for signal isolation in hazardous areas, IS-1 series intrinsic safety modules of Stahl are used. It has its own redundant PROFIBUS DP interface, which is directly connected to PCS7 redundant i/o bus system, and is equipped with a drive module conforming to PCS7 standard, which ensures the safety and reliability of the whole scheme, and the system is relatively consistent and more economical

--- our plan also includes 29 PA intelligent instruments, which transmit a large amount of status information while transmitting process control signals to the operation station. With the guidance function integrated by PDM equipment management software and all communication components, the parameter setting and debugging of all instruments can be completed in the central control room. Thus, it provides great convenience in the installation, commissioning and subsequent maintenance of the device, and greatly reduces the cost of materials and manpower