CONTROL SYSTEM OF BIOMASS GASIFIER USING PLC

International Journal of Engineering and Techniques - Volume 1 Issue 2, Mar - Apr 2015RESEARCH ARTICLEOPEN ACCESSCONTROL SYSTEM OF BIOMASS GASIFIER USING PLCL.SAROJINI1, P.KAYALVIZHI2, D.AJAY ABILASH31(Assistant professor, Department of electrical and electronics engineering, Periyar maniammai university, thanjavur)(M.tech( Automation and control system), Department of mechanical engineering, Periyar maniammai university, thanjavur)3(M.tech( Automation and control system), Department of mechanical engineering, Periyar maniammai university, thanjavur)2Abstract:India has many no of renewable energy resources. In that Biomass Gasifier plays a major role as an alternate energysource. But it facing lot of practical problems on operation due to shortage of manpower and also several problems mayhappen in these gasifiers. To overcome the above problems we go for automatic control systems in this gasifier. Therefore wecan neglect the human efforts, errors and operators of the gasifier won’t get affected by the out coming gases from thegasifiers due to this automation. The gasifier itself works according to the program which we have given. Automation is donein the miscellaneous function, fuel feeding system and all biomass gasifier control system by using PLC (Programmable LogicController). And then we develop the ladder logic program for sequence of operation in gasifier control system. In this systemthe ladder logic function is programmed by using INDRALOGIC software and the hardware component of PLC is RexrothBosch product.Keywords: Programmable logic controller (PLC), Biomass gasifier, Indralogic.I. INTRODUCTIONBiomass gasifier is an alternate source usedfor power generation and thermal applications. Lotsof biomass fuels are available in rural areas. Someof the biomass fuels are wood waste, sawdust,briquettes, seed cakes, coconut shells, etc., Theseare available at low cost. So we can generate powerat minimum cost using these fuels even though lotsof practical problems occur in the biomass gasifiers.They are s follows i) Gasification is a involutes andsensational process, ii) To start the process, gasifierneed at least half an hour of time, iii) Removal ofash and tarry contents and its handling is a dirty andtime consuming process, iv) Getting the producergas in a proper state is difficult, v) These gasifiersrequires frequent refilling of the fuel. To overcomethe above problems automatic control system isneeded. The control system of biomass gasifier iscapable of offering a wide range of solutions to suitthese needs. These are achieved by utilizing avariety control system like embedded system or plccontrol system [1].The embedded system is used to performingthe specific task and the hardware components ofembedded system is very low cost compare to plc.ISSN: 2395-1303But it has few disadvantages like it does not use inhigh temperature region, Very less input/outputmodules, modification of program is not possible.For the above reasons the embedded system is notsuited for biomass gasifier control system. Hencethis paper is fully focused on control system ofbiomass gasifier using PLC.II. PLC OPERATIONPLC is a solid state digital computer used toperform control functions in the industrial processessuch as assembly lines and machinery. It doesn’thave mouse, CD drive. Keyboard, disk drives andmonitor like PC but it has communication ports andinput/output terminals for devices. It is entirelydifferent from PC. PLC is designed for large no ofinput/output and it has extended temperature ranges,resistance to electrical noises and vibration. Theoutput of the equipment is controlled by the PLCbased on the input conditions. It has different typeof operations such as arithmetic, logical operation,on/off operations, sequencing, timing, and counting.In industry, PLC just replaces the control systemsand wiring connections between the devices.Instead of connecting wires directly between thehttp://www.ijetjournal.orgPage 41

International Journal of Engineering and Techniques - Volume 1 Issue 2, Mar - Apr 2015devices, PLC provides wiring connections to themby connecting all wiring connection to the PLC.This is called soft wiring. PLC has memory, in thatcontrol program is stored. It performs operationsaccording to the program.PLC has many advantages over othercontrol systems. It is known for its flexibility, lowcost, operational speed, reliability, ease ofprogramming, security, and it is easy inimplementing changes and correcting errors [3].Push buttonLightsPLCSensorsMotorsFig.1. Typical functional components of PLCA. Components of plcPLC consists of the following components i)Central processing unit ii) Memory iii) Input/outputiv) Power supply v) Programming device vi)Programming methodsCPU is the main component of the PLCsince it is the nervous system of the controller and itis the decision maker. It consists of microprocessorand memory. These parts perform type ofoperations listed above. In PLC, memory is used tostore data or information used for the process. Itmakes decisions according to the instructionspresent in the memory. They are RAM, ROM,EPROM and EEPROM. The input/output devicesact as the interface between the controller and fieldfiequipments. Typeses of input/output devices areanalognalog and digital devices. I/P analog devices aretemperature and pressure sensor. Pushbuttons andlimit switchess are I/P digital devices. The analogaO/P devices are hydraulic and pneumatic valves.Motor, lamp is examples for O/P devices. Internalcircuits of the PLC are supplied with the DC power.Power is not supplied to the field devices throughpower supply in larger PLC system. This can beachieved by external current supplies for safetypurpose. For enteringntering the desired program we needa programming device, for this purpose PC can beused. Each brands of PLCs has desired softwarefrom their manufacture we can use this software inPC and we can program in our computer. PC andPLC can be connected througthrough communicationports; we can edit and save our desired program inPCs. Several methods of programming are available,in that ladder logic is the universally accept method.It looks like a ladder hence it is called ladder logic.The input and output devicess are symbols. Thehorizontal line is referred to as rung and otherwisecalled as network. The left vertical path indicatesthe power supply and right vertical line is the returnpath or neutral line.III. HARDWARE AND SOFTWAREDESCRIPTION OF PLC IN BIOMABIOMASSGASIFIERPLCs may need to interact with people forthe purpose of configuration, alarm reporting oreveryday control. A Human--Machine Interface(HMI) is employed for this purpose. HMIs are alsoreferred to as MMIs (Man Machine Interface) andGUIs (Graphicalphical User Interface).A simple systemmay use buttons and lights to interact with the user.Text displays are available as well as graphicaltouch screens. More complex systems useprogramming and monitoring software installed ona computer, with the PLC connected via acommunication interface [2].A. HardwareThe hardware components used for thedevelopment of this setup are Rexroth Bosch PLC,push buttons, DC wiper motors, limit switches,Proximity sensors, Air blower, Electronic Igniter,Connecting wires.es. Details of each component aredescribed below:1. Rexroth Bosch PLCThe Indralogic L20 of Rexroth is a compactPLC including a standardized I/O system on thebasis of terminal technology and is designed for

International Journal of Engineering and Techniques - Volume 1 Issue 2, Mar - Apr 2015logic operation. Operation is only permitted in thespecified configurations and combinations ofcomponents using the software and firmware asspecified in the relevant function descriptions.Typical applications of Indralogic L20 areHandling and assembly systems, Packagingand foodstuff machine, Printing and paperprocessing machines, Machine Tools. TheIndralogic L20 may only be operated under theassembly, installation, and ambient conditions(temperature, system of protection, humidity, EMCrequirements etc.,) [4].y sensorsA proximity sensor is used as the inputdevice for sensing the level of fuel in the storagechamber. It can detect the nearby object withoutany physical contact of the sensed object. There areno moving parts in it so it can withstand for longduration and it has high reliability.3. DC Wiper MotorDC Wiper motor act as the drive system forconveyor operation, door open close operation andthe control system of motor is achieved byprogrammable logic controller (PLC).4. Push buttonsTABLE ISPECIFICATION OF REXROTH BOSCH PLCPush buttons is made up of hard material orplastic used for simple switching operation. Here itacts as the input device and used for start and stopoperation.5. Limit switchesLimit switch is a mechanical switch whichconverts mechanical movement into electricalsignal. It is actuated by the physical contact of theobject. In this control system, limit switches areused to control the door open close operation.DescriptionSpecificationProcessorST microelectronicsST40 with 192MHZWorking memory16MbytesDRAMand64kbytesNVRAM.Inputs8 digital inputs (24VDC supply)Outputs8 digital outputs(24V DC supply)CommunicationInterfaceEthernet connectionor Serial RS232interfaceUser memoryprogramWeightISSN: 2395-1303for1Mbytes200 gramsIV. SOFTWARE DESCRIPTIONIn this paper, software used for the PLCsystem is “Indralogic”. Here ladder logic is used asthe programming language. It is a symbolicrepresentation of control logic or set of instructions.This program is to be entered in to the plc memoryfor execution of real time process.V. INTERFACINGPLC used in this system is REXROTHBOSCH with 8 digital inputs and outputs. The inputports are connected to the four limit switches andthree sensors. The output ports are connected to theconveyor, blower, igniter, and motors for doormovement. PLC consists of an on delay timer usingthat timing pulse can be generated in the necessaryplace. The I/O port addresses are specifiedaccording to our input/output port requirements inthe plc. While interfacing PLC must be connectedto the specified I/O devices in the appropriate port2. address and then ladder program is created by usingProx PLC software. Addresses are given in the programimit must matched with those in the i/o port addresshttp://www.ijetjournal.orgPage 43

International Journal of Engineering and Techniques - Volume 1 Issue 2, Mar - Apr 2015after that desired program is downloaded into thePLC memory for real time working.Fig. 2 Interfacing PLCVI. RESULTS AND DISCUSSION:After the interfacing process is done withbiomass gasifier setup, complete checking is donefor detecting errors and trials were done and theproposed setup was successfully worked as per thegiven control system.When the push button is pressed for the firsttime means, storage chamber door1 will get openedfor getting the fuel by the conveyor, if sensorsdetects the predetermined level of the fuel in thechamber,, door1 get closed and conveyor also cutoff,, then fuel get transferred into the hopper region.Blower will automatically turn on by the controllogic and after some time delay igniter also will on.If temperature reaches the 60 degree Celsius in thegasifier,ier, igniter will automatically turn off.Whenever fuel reaches the minimum level, startingprocess will happen for one more timeautomatically. It is clearly seen that gasifier setupworked successfully according to the control logicspecified in the program.Fig. 3 ladder diagram for biomass gasifier controlsVII. CONCLUSION