Boiler DCS control system

一. One Boiler Overview

The boiler is an important power equipment in the entire plant, whose task is to supply qualified and stable steam to meet the needs of the load. Therefore, all major parameters of the boiler production process must be strictly controlled. Boiler equipment is a complex control object, with the main input variables being load, boiler feedwater, fuel quantity, desuperheating water, supply air, and induced draft air volume. The main output variables include steam drum water level, superheated steam temperature and pressure, flue gas oxygen content, and furnace negative pressure. Therefore, the boiler is a complex control object with multiple inputs, outputs, and interconnections.

二. Boiler computer control system
    As a boiler control device, its main task is to ensure the safe, stable, and economical operation of the boiler, and reduce the labor intensity of operators. Adopting microcomputer control, it can perform multiple functions such as automatic detection and control of the boiler process.

      
    The boiler microcomputer control system generally consists of the following parts: boiler body, primary instrument, microcomputer, manual and automatic switching operation, actuator and valve, slip motor, etc. The primary instrument converts the temperature, pressure, flow rate, oxygen content, speed, etc. of the boiler into voltage, current, etc. and sends them to the microcomputer. The manual and automatic switching operation part is manually controlled by the operator, and the slip motor and valve are controlled by the operator. In automatic mode, control signals are sent to the microcomputer through the execution part for automatic operation. Microcomputer monitors, alarms, and controls the operation of the entire boiler to ensure its normal and reliable operation. In addition, to ensure the safety of boiler operation, conventional instruments and alarm devices should be installed for important parameters such as boiler water level and steam drum pressure during microcomputer system design to ensure that there are dual or even triple alarm devices for water level and steam drum pressure. This is essential to prevent major accidents in the boiler.

Network configuration instructions

三、system performance 

1、Real time performance

The response capability of the system meets the functions of data collection, human-machine communication, and control, and the communication time of the system meets the process requirements. The specific indicators are as follows:

1、Digital acquisition cycle＜1ｓ

2、Data storage interval＜1ｓ

3、Control command response time：

    ａ.Control command response time＜1ｓ

    ｂ.Response time from accepting execution command to executing control＜1ｓ

4、Analog acquisition cycle:

    ａ.Electricity level＜1ｓ

     ｂ.Non electric quantity＜1ｓ

5、Response time of monitoring system to on-site system data collection and control＜1ｓ

6、Response time for human-machine communication:

  ａ.Response time for calling a new screen: The CRT response time from the operator issuing                 a new image command to the image being fully displayed on the CRT is less than 1                             second;

      Response time from alarm or event occurrence to CRT screen display and issuance：＜＝1ｓ

        ｂ. Dynamic data update cycle on the displayed screen＜2ｓ。

2、reliability

This system, as well as various electrical and instrumentation equipment, can adapt to the working environment of this project, with extremely high cost-effectiveness, anti-interference and stability, and can operate stably for a long time in such an environment.

3、Maintainability

    The software and hardware products we provide in this system are easy to maintain, test,                    install, and troubleshoot.

  1、Maintainability parameters are generally less than 1 hour.

  2、The equipment selected for the system has self diagnostic and fault finding programs,                        indicating the specific fault location. After replacing the faulty component on site, it can                    work normally.

  3、Equipped with disconnect points for easy testing and fault isolation

  4、Equip appropriate equipment specific maintenance and installation tools.

  5、Provide appropriate maintenance and upkeep measures to reduce the chances of human                  and mechanical damage.

  6、Indicate the purpose and replacement method of the equipment through identification                     signs.

        7、The selected device has strong hardware substitution capability.

     4、Utilization rate

  1、This system is composed of high-performance and highly secure components that make up               our design system.

  2、The availability rate of this system should not be less than 99.9% during the 30 day trial                    operation period before handover, and should reach 99.8% during the warranty period after              equipment acceptance.

5、System security

The system has measures to ensure operational security:

ａ.Provide inspection and verification for every function and operation of the system, and can                alarm and cancel any errors found.

ｂ.When there is an error in operation, it can be automatically or manually disabled and alarmed.

Security measures for communication systems:

ａ.The system design should ensure that errors in information transmission do not lead to                      critical system failures.

ｂ.Appropriate inspection methods are provided on the channel equipment to confirm that the              channel is functioning properly.

The security measures taken for the hardware, software, and firmware used in the system:

ａ.There is power failure protection and automatic restart.

ｂ.Can preset initial state and reset.

ｃ.Has self checking capability and can automatically sound an alarm when a fault is detected.

ｄ.Equipment failure can automatically cut off or switch and send out alarm signals.

ｅ.Any hardware or software malfunction will not jeopardize the integrity of the system and                    personal safety.

6、Scalability

To determine and implement system expansion, manufacturers should provide limitations          on system scalability, mainly including:

ａ.The maximum capacity of the main control level memory.

ｂ.Use limits related to routines, addresses, flags, or buffers.

ｃ.Data rate limit.

ｄ.Design and operational limitations such as interface modifications or component                                repositioning when adding components.

The expandable scope of the system is as follows:

ａ.The backup points shall not be less than the design requirements.

ｂ.Leave interfaces for expanding local control devices, peripheral devices, or system                              communication.

ｃ.There should be sufficient margin for channel utilization or channel data rate.