Overview of Automatic Control System of Municipal

1 Introduction 　　Urban municipal solid waste incineration power generation is to collect municipal solid waste and send it to a municipal solid waste incineration power plant for incineration. The domestic waste is incinerated at a high temperature, and the heat energy generated during the high-temperature incineration is converted into high-temperature steam, which pushes the steam turbine to rotate and causes the generator to generate electrical energy. 2 Engineering Overview The first phase of the waste incineration power generation project is composed of three 400t/d waste incineration lines, two 12MW steam turbine generator sets and auxiliary public systems. 　　Waste incineration power plant is mainly composed of waste incineration system, waste heat utilization system, flue gas treatment system, sewage treatment system, etc. 3 Automatic control method of thermal control for waste incineration power generation According to the characteristics of the waste power plant process flow, the control system is mainly composed of a distributed control system (DCS), an incinerator combustion control system (ACC), a flue gas continuous measurement monitoring system, a steam turbine control system (DEH), and a steam turbine emergency trip system (EST) , Steam turbine safety monitoring system (TSl), auxiliary workshop control system and other parts. 4 Composition of DCS system for waste incineration power generation 　　 The DCS control system completes the monitoring of three incineration lines and two turbo-generator sets and their auxiliary public systems. The DCS control system consists of servers, field control stations, engineer stations, operator stations, redundant communication networks, field instruments, etc. 　　4.1 Functions of monitoring system The data acquisition system (DAS) has graphic display functions, alarm management, tabulation records, historical data storage and query functions; the analog quantity control system (MCS) can meet the requirements of safe, reliable, stable and efficient operation of incinerators, boilers, steam turbines and their auxiliary systems Sequential control system (SCS) is based on program control, which controls interlocking of incinerator, control of incinerator grate, interlocking protection of steam turbine, etc. 4.2 The composition of the monitoring system 　　 (1) On-site control station 　　 Control station is composed of main control unit controller, analog input and output card, switch input and output card, network communication and other units. The main control unit controller adopts dual-machine hot standby redundant structure, and the communication system is also dual-network redundant. 　　 (2) Operator station 　　Operation station and engineer station usually complete the objects they control, and they need to log in through password identity verification and grant corresponding authority. 　　 (3) Printer 　　The control system is provided with a printer (for printing of events, alarms, graphics, data, etc.), which is placed in the engineer station. 　　 (4) GPS device 　　The GPS device is connected to the server of the DCS system. 　　 (5) Power supply 　　The power supply cabinet is equipped with redundant power switching devices and loop protection equipment. 　　4.3 Monitoring system reliability measures 　　Equipment redundancy configuration, important protection and trip functions of boiler and unit adopt independent multiple measurement channels, trip circuit adopts three-take two logic, ten-take three logic. When the main control system is global or has a major fault, in order to ensure the emergency shutdown of the unit, an emergency stop button independent of the main control system is set. 　　4.4 Communication network of DCS monitoring system 　　DCS system external equipment communication network is provided and supported, RS323 RS422/485 interface MODBUS protocol, and PROFIBUS-DP field bus, HATE protocol, etc. DCS is connected to a plant-level monitoring information system (SIS) with a data acquisition interface. The data acquisition interface function is completed by an independent operator station and a firewall is provided. 　　4.5 Control method of waste incineration waste heat boiler 　　 DCS as the core monitoring system, while providing MODBUS and PROFIBUS-DP two communication protocols to communicate with the control subsystem. The communication between the integrated combustion control system (ACC) of the incinerator and the main control system of the incineration waste heat boiler realizes the automatic control of the grate hydraulic system through the PLC (S7-300) and accepts the oxygen content, furnace temperature and main steam flow signals from the DCS. Automatic combustion control. 　　4.6 Flue gas purification treatment system 　　 Bag dust control system is equipped with a set of PLC, which communicates with DCS system through RS485 interface. Pneumatic ash delivery system directly enters DCS system for monitoring and operation. 　　4.7 Auxiliary workshop control system 　　 Sewage treatment control system is a complete set of independent control system (DCS), only the necessary monitoring control is communicated to the main DCS system for monitoring through OPC protocol. Garbage grab control system. The system adopts PLC control. The equipment is operated in the main control room of the garbage crane. DCS does not have control monitoring. 　　4.8 Smoke online monitoring system (CEMS) 　　Flue gas online monitoring system is equipped with independent monitoring probes at each flue gas outlet of the incineration line, and is equipped with independent monitoring and analysis equipment. 　　4.9 Waste heat boiler soot blowing system 　　Incineration waste heat boiler acetylene pulse soot blowing system comes with PLC control system, which controls the soot blowing time and frequency. 　　 5 Combustion control subsystem of incinerator The incinerator combustion control subsystem includes: boiler feed water three-impulse cascade adjustment system, superheated steam temperature cascade adjustment system, furnace negative pressure adjustment system, flue gas purification treatment control system, sequential control system (SCS), boiler interlock protection system (MFT), integrated combustion control device (ACC). 　　 6 Steam turbine control system structure The steam turbine monitoring system with DCS as the core includes: steam turbine emergency trip system (ETS), steam turbine safety monitoring system (TSI), steam turbine digital electro-hydraulic regulation system (DEH), condenser hot well water level automatic regulation system, hydrophobic regulation system, Water jet vacuum adjustment system, shaft seal adjustment system, circulating water adjustment system, deaerator analog quantity control system (MCS), deaerator liquid level automatic system, deaerator pressure automatic adjustment system. 　　 7 Industrial TV monitoring system 　　Industrial TV monitoring system server is placed in the electronic room, and a monitor is set in the central control room. The industrial TV system is set with a set of servers to query and monitor in real time through the network. The basic monitoring objects are: door guard room, weighbridge room, garbage discharge platform, garbage hopper, furnace flame monitoring, steam drum water level, slag outlet, chimney, plant and other important equipment safety and security management points. 　　 8 Conclusion 　　Due to various reasons, the research and application of domestic waste incineration technology started relatively late. The research of waste incineration technology lags behind the development needs. At present, China lacks both industry standards and professional specifications, and it also lacks complete, mature and systematic design technology. The characteristics of the waste incineration technology applied in developed countries represent the forefront of the current domestic waste incineration technology. At the same time, the applied waste incineration technology also has a considerable guiding role in the future development of waste incineration technology.