Flue Gas Desulfurization


Design, configure and provide start-up support for a control system using Rockwell ControlLogix, Siemens APACS, and Wonderware InTouch to control a flue gas desulfurization system at a coal fired power plant.

  • Desulfurization reactor and support systems including carbon injection, lime storage,
    bag house and ash storage
  • Five (5) Rockwell ControlLogix PLCs
  • Siemens APACS BOP controls
  • Siemens Quadlog BMS
  • Wonderware InTouch Client/Server Application
  • Wonderware Historian

The project added five (5) Allen-Bradley ControlLogix PLCs and four (4) PanelView Plus OITs to a greatly expanded process control Ethernet network. The PLCs were used for control of a new desulfurization reactor and support systems while the modified APACS/Quadlog system continued to control the remainder of the plant.

Applied Control Engineering, Inc. (ACE) was responsible for PLC panel design, development of the AQCS PLC program, all changes to the existing systems, all HMI additions and integration with existing historian. The AQCS PLC consisted of one rack containing the processor with the I/O remotely mounted and communicating to the PLC via Ethernet I/P. Configuration of this PLC included interlock logic, process calculations for controlling reagent feed rates, and interfaces to CEMS and other vendor systems.

The HMI screens were created and integrated into the existing BOP system and seamless navigation was provided. The HMI included displays for all vendor supplied systems.

In addition to the control system design and development, ACE built an AspenTech HYSYS based dynamic process model to analyze and develop control strategies.


The system is currently fully operational and provides the operators with exceptional access to all portions of the plant.