Blast Furnace DCS Control Solution

The process for producing blast furnaces is consecutive, where the first generation of blast furnaces (from commencement of work to stopping work for major maintenance) can continue production over a dozen years. Short disruptions in between will result in immeasurable losses during the production process. This would raise the reliability requirements required for the control system. HollySys combines the characteristics of the blast furnace iron-smelting system and the different requirements of the user based on the HOLLiAS MACS automation control system to provide targeted and customised solutions to its clients.

The HOLLiAS MACs of the HollySys system is designed based on the concept of a safety system, ensuring product reliability in terms of hardware and software.

•  Adopts definite real-time industrial Ethernet protocols regardless of changes in communication load and without any data clashes, ensuring system network reliability.

•  Adopts full-redundancy technology to ensure product reliability.

•  Adopts isolation technology. Photoelectric isolation is adopted to isolate the system bus from the modules, and DC/DC isolation is adopted to isolate the system’s power source from the module power source. The module channels are completely isolated from each other using electric isolation.

•  Completely non-interfering downloading technology. Regardless of whether they are program amendments, measuring points for additions/deletions, or addition/deletion hardware, HollySys’ DCS system can conduct downloading operations when the site system is operating normally, and there will not be any interference to production activities.

•  Human errors are reduced as much as possible when operating at different authority levels and on different processes or equipment, and when checking the rationality and legality of input data, ensuring the system’s operational safety.

•  Many self-diagnostic functions. The system provides diagnostic capabilities from system-level, module-level, to channel-level.

Sintering waste-heat power generation DCS control solution

In terms of overall power consumption during sintering processes, nearly 50% of heat energy are emitted into the atmosphere as sensible heat via sintered flue gas and coolant exhaust. The energy conservation potential is huge. As the world’s energy sources become scarce, waste heat recovery in the iron and steel industry can save a lot of energy and reduce power consumption during the production process. As the waste-heat recovery (WHR) technology soared, especially with breakthroughs in flash power and admission condensing steam turbine technologies, WHR efficiency has significantly improved.

HollySys’ DCS system control solutions:

(1)  Data Acquisition System (DAS)

(2)  Modular Control System (MCS)

•  Automatic regulation to reduce temperature of warm water (cascade PID)

•  Condensate regulating valve opening control (single PID)

•  1# Medium pressure water feed pump frequency control (soft manual control)

•  2# Medium pressure water feed pump frequency control (soft manual control)

•  Equalising tank pressure regulating valve position control (Single PID)

•  Valve position control for condenser regulation gate using chemical fluid (Single PID)

•  Condensate pump 1 converter control (soft manual control)

•  Condensate pump 2 converter control (soft manual control)

•  1# wind room inlet smoke path electric air door A control (soft manual control)

•  1# wind room inlet smoke path electric air door B control (soft manual control)

•  2# wind room inlet smoke path electric air door A control (soft manual control)

•  2# wind room inlet smoke path electric air door B control (soft manual control)

•  Segment I high temperature smoke path electric air door opening control (soft manual control)

•  Segment II smoke chimney electric air door opening control (soft manual control)

•  Segment II low-temperature smoke path electric air door opening control (soft manual control)

•  Bypass smoke chimney electric wind door opening control (soft manual control)

(3)  Sequence control system (SCS)

•  Mutual standby boiler feedwater pump start / stop sequence interlock control

•  Mutual standby condensate pump start / stop sequence interlock control

•  Mutual standby circulating pump start / stop sequence interlock control

•  Mutual standby water-jet pump start / stop sequence interlock control

•  Steam turbine oil pump functional set start / stop sequence interlock control

(4) Steam turbine accident trip system (ETS)

HollySys DEH main functions

As automation level requirements increase, better control can be achieved for changing the speed of steam turbines for economical and reliable operations. The DEH has functions that achieve process control commencement, automatic regulation, parameter control, protection, monitoring, and testing. 

Integrated control of air separation units and compressors

Air separation units (ASU) and compressors shall be treated as a single controlled entity, where its advantages are mainly presented in the following points:

•  Standardised human machine interface: Inter-switchable with the GUI (graphical user interface) of the ASU.

•  Data sharing: Shares data directly with ASU system

•  Convenient to configure

•  Flexible control strategy: ASU test points can directly participate in the interlocking and control of turbines

•  Dynamic response time and accuracy that improves control effectiveness: Control cycle set at at-least 50ms. Speed change control accuracy <±2 revolutions/minute

•  Convenient to communicate

•  Convenient to maintain: Just like ASU system software and hardware, the software is easy to use and the hardware is easy to maintain.

•  Highly expandable

Parallel monitoring of steam turbine and ASU is done from an independently established IO control station that is separate from the ASU system, as shown in the following network architecture diagram: 

The control interlock logic includes:

1)Allows start and emergency stop interlocking

2)Anti-surge control

3)Blower control

4)Protection restriction function

5)Auxiliary equipment control

Integrated turbine blower control solution 

Leveraging on its experience in the design and implementation of over 1000 DEH equipment and the practical application of blast furnace blower, HollySys has established a complete package of integrated control solution for turbine blower system. With the turbine and blower treated as a single controlled entity, its strengths are mainly shown in the following ways: standardised human-machine interface for ease of operations by operator; flexible configuration, which facilities functional expandability; fast system dynamic response, which facilities high accuracy; convenient maintenance.   

Turbine blower integration control solution allows for the ease of adjusting the change in blower speed, wind volume, and wind pressure with few occurrences of overshooting. With high control accuracy added into the picture, the automation level of blast furnace blower operations can be increased. Its effects are mainly shown in the following technological indicators:

•Speed control range: Jigger rotational speed~3600r/min

•Rotation speed control accuracy: :<±1r/min

•Overshoot level under maximum acceleration: <0.15% rated rotational speed

•Maximum rise in rotational speed under load shedding: < 8% rated rotation speed

•Droop in rotational speed: 3-6% consecutive adjustability

•Control system insensitivity: <0.06%

Integrated control solutions include:

1)  Allows start and emergency stop interlocking

2)  Anti-surge control

3)Reverse current protection

4)Blower control

5)Protection restriction function

6)Auxiliary equipment control

The key auxiliary equipment controls include: steam turbine oil jacking pump control, lubricant AC electric pump control, lubricant DC electric pump control, power oil pump control, jigger motor control, condensate pump control, and water-jet pump control.