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Solution of the dusting and deslagging system in power plant

The dusting and deslagging system in powerplant aims to gather, store and transport dust and ash residue from the firecoal in the furnace to appointed place ( for example ash site and ashwarehouse). The whole system is a very important supporting system for the heat-engineplant and also an important system for ensuring continuous and normalelectricity generation of the machine set, which includes the deslaggingsystem, the slag-water separation system and the ash-slag transportationsystem; while the dusting system includes the flying ash system, the warehousepump, the ash discharging pipeline, the dusting air compressor system and theash warehouse system etc.

The whole system applies PLC with high costperformance to concentrated control equipments, while the hot-standby uppercomputer system of offers security assurance to software. It has perfectconfiguration function, which promotes production automation level of dusting,guarantees normal operation of the machine and reduce work load and expenses onmaintenance and recondition. Operators in the monitoring system can accuratelyknow about the material location and operation state of the warehouse pump,which offers effective signal ground to operate the warehouse pump, promotesoperation efficiency of equipments such as the warehouse pump, reducesexhaustion of equipments and waste of energy, ensures normal operation of thewhole system according to technological requirements and offers forceful guaranteeto normal operation of the power plant.

Operators can design the monitoring picture viathe upper computer (the operator station) according to technological processand concentrate on monitoring the dusting and deslagging control system; LCDpicture can show technological process, measurement parameters and operationcondition of equipments; has functions such as gathering and displaying data,storing and managing data, outputting alarm, storing historical data andgenerating reports etc and is connected to the network printer, which canconveniently generate various reports and documents needed in the productionprocess, show parameter off-limit alarm with different colors and malfunctionof the controlled member (signal alarm function) and print measurement parameterand alarm signal (recorder function) etc.

The system uses double-loop power supply, whichcan be spared and automatically switched over in the power cabinet. When theworking power supply breaks down, it can automatically and rapidly switch overto the spare power supply and make sure that any part of the system won’t losselectricity on condition that any power supply breaks down without influencingnormal operation of the control system. In order to ensure continuous powersupply even stability of power supply in the system, UPS continuous powersupply device is connected in the system.

Ground operation box is set around thetechnological equipment, the operation box has automatic / manual change-overswitch and hand-operation switch, which are convenient for debugging of equipmentsbefore automatic commissioning and malfunction recondition in the operationprocess.

According to technological requirements of thesystem, rich picture display is designed, vividly and dynamically showing the layoutdiagram of the dusting warehouse pump and the ash-transport pipe valve,besides, different colors are applied to reflect operation state of all equipments.The system has control functions such as simulation, remote operation,automatic control and manual control etc and can realize various controlmethods to equipments. The upper computer monitoring system shows data such astime, current and pressure etc via bar graph and tendency chart etc to formeffective data analysis chart. The system has perfect alarm treatment, when itissues alarm, the alarm picture will spontaneously jumps out, showing alarmcontent and recording it for convenient query and printing. In order to promotesafety of the system, when there is malfunction, relevant measures can beautomatically taken according to the type, which has protective function toovercurrent, overload and abnormal medium. Both hardware and softwareconfiguration in the system has extendibility, which can be conveniently extendedto the auxiliary control system and realize centralized control in the wholeplant.

Display of technological flow sheet

The technological flow chart includes theoperation monitoring diagram of the negative pressure system of the furnace,which is used to timely monitor and operation the furnace; the monitoringdiagram of the negative pressure system is used to monitor the negative pressuresystem; while the monitoring diagram of the warehouse pump system is used totimely monitor and operate the positive-pressure warehouse pump system.

Data management

The system collects data and reflects them inthe simulation picture, generates timely report via report tools and storesthem via historical record function for generating historical trend and report,which offers reliable ground to analyze technological data. The system cangenerate file to analysis result of these data conveniently for outputting orstoring.

Alarm function of the system

The system has perfect alarm function, whichcan show state by different colors in the monitoring picture of equipments;limit-value alarm is set in the analog quantity, while state-transition alarmis set in the switching value with special overall alarm picture to show allalarm states and relevant information. The system is matched with voice alarm, whichcan conduct voice prompt, conveniently offer alarm information to workers andpromptly handle accidents. The alarm can be stored so as to offer ground torecall accidents.

Network function of the system

The system used double-machine hot backup functionof the monitoring configuration software to configurate the two upper computersof the monitoring center as redundancy mode, ensuring that the system is safe,historical data can be handled once and the data is reliable and complete. Extendibilityof the network offers communication interface to the auxiliary control systemfor convenient communication.

Malfunction query and treatment

In process of operation, the IndustrialPersonal Computer tweets and prompts alarm when there is breakdown, the operatorcan switch over to the main picture, click alarm general view and open thepicture for query.

According to prompts in the description of thealarm general view about breakdown, the operator should remove breakdowns incorresponding position on the scene.

Event record query

The system also offers event record and query function(mainly referring to the warehouse pump system), namely operations of allvalves can be queried so as to offer subsidiary help to inquire breakdowns.

Characteristics of the system: the dusting anddeslagging control system uses PLC control and LCD monitoring to operate thecontrol mode with advanced technique, perfect function and strong logicality,which ensures safe and reliable operation; it has the followingcharacteristics:

The automatic control device applies full-automaticprogram control with high automaticity. The system operates in cycle at fixedtime with little labor participation.

Complete and reliable monitoring means. Thedusting and deslagging control system can observe and control operationcondition of the system on LCD; the PLC control system has double-machine hotbackup function, when LCD breaks down, they can switch over each other toensure normal operation of the system.

The control way of LCD not only avoids malfunctioncaused by bad contact and disqualified quality of routine control switch under severeenvironment in the power plant, but also reduces cost and promotes costperformance.