A Three-Stage Material Process Control System Based On SIMATIC PCS 7

Siemens SIMATIC PCS 7 is a process control system with many automatic functions that can be used in the configuration of a project fast and conveniently.It provides many options for creating individual,project-specific solutions.PCS 7 is based on modular,functionally coordinated Simatic hardware and software components of a Totally Integrated Automation system.It is a homogenous and integrated overall DCS,with central engineering and a common database,which enables the complete automation of both manufacturing and process engineering processes and is used in the process,production and hybrid industries.This thesis expounds the control of a three-stage material process of a chemical plant on a SMPTLab simulation environment;the control program is designed using PCS 7.The complete system is comprised of a single computer performing the work of both the engineering station(ES)and operator station(OS);an S7 400 programmable logic controller(PLC);second computer containing the SMPTLab simulation environment;and a PM125 module as a communication interface between the simulation environment and the PLC.The Control System's description is categorized,mainly,into chapters: Two,Three,and Four.A brief introduction and background of Process Control are given in the First Chapter;the Chapters Five and Six present the overall results of this Control System and a Summary of the work covered in this Thesis respectively.A description and control index of the Three-Stage Material Process is given in the Second Chapter.The material processing starts from the mixing tank,where two reactants are mixed uniformly at specified proportions;the mixture is then delivered to the reactor.Here,a specified amount of a catalyst is introduced;a chemical reaction takes places forming a new product.The products of the reaction are then carried to the final stage which is the flash tank;the purification process of the required product takes place here.The objective is to effectively control the levels of the materials in all stages,reactor temperature,and flash tank pressure at specific setpoint for better yields in the final product.The following control circuits,namely: fixed setpoint control,cascade control,and multi-loop ratio control are essential in the aforementioned objective.Fixed setpoint control is used to set the required require inside the flash tank and the flow of the final product of reaction from the flash tank.Cascade control is used in holding the levels in the mixing tank,reactor and flash tank by fixing the inlet or outlet flow;it is also used in regulating the reactor temperature by controlling the flow of the cycling cooling water around in the reactor.Multi-loop ratio control,on the other hand,is used in specifying flow setpoints of the reactants using their required concentrations.Sequential control algorithms are also designed to run the Startup,Shutdown and Emergency Shutdown Processes.The Third Chapter elaborates the Control System's hardware configuration.The hardware consists of an ES/OS computer,an S7 400 PLC,a PM 125 module and an SMPT-1000 device housed in the SMPTLab simulation environment.Network configurations are made by connecting the ES/OS to the PLC via an Ethernet cable;and with the aid of a Profibus-Dp cable,the PLC establishes communication with the SMTP-1000 device,using the PM-125 as the interface moduleThe Fourth Chapter covers the description and configuration of the ES and OS.SIMATIC PCS 7 Software Tools are used to execute both the ES and OS.A PCS 7 project is created in a properly configured ES;a control program is designed using CFCs and SFCs in the project,in accordance with the specifications given in the Second Chapter.A fully configured control program constitutes an Automation Station.CFCs are used in controlling continuous processes like the flow of Materials,maintaining the tanks and reactor levels,maintaining the reactor temperature and pressure regulation in the flash tank.SFCs are used in controlling sequential operations,namely: The Startup,Shutdown,and Safety Shutdown process in the system,as described in the Second Chapter,as well.The Startup process oversees the start and completion of the three-stage material process in the system.It ensures delivery of materials in and out of the system;it also ensures the reactor temperature,the flash tank pressure and the tanks and reactor levels are kept at the operator's setpoints.The Shutdown process executes by subsequently emptying the tanks and reactor,turning off the pumps and closing the flow valves until the flash tank is empty.The Safety shutdown process is deployed in case of an emergency;it effectively cuts off material flow into the mixing tank and then fully drains the rest of the system.An OS is compiled from a fully configured Automation Station;additional changes in design are carried out using WinCC design tools.The OS platform provides a clear view of the system in which proper monitoring and control are carried out.