An advanced nitrous oxides (NOx) control system for a Selective Catalytic Reduction (SCR)
There is currently considerable worldwide concern in environmental emissions such as NOx. Environment protection is now more important in operating power plants. Penalties for violating environmental emission rules are established.
NOx is reduced through improved combustion methods. Furthermore the SCR facilities are used to reduce NOx.
The NOx control loop is known by its difficulties. The NOx emission is fluctuated by the process characteristic (combustor, SCR, Analyzer, etc.). It caused the excessive ammonia consumption and emission to keep the NOx emission under the given set value.
Toshiba provides a new NOx control system for a SCR with advanced control methods.
This control system has excellent control performance and is able to shorten the tuning period and reduce cost for tuning work in commissioning.
Benefits
This control can keep the NOx emission to the given set value and prevent excessive ammonia consumption.
Toshiba has the following results in a recent control system upgrades.
(1) Superior environmental protection
- NOx fluctuation is reduced by 75 %
(2) Operation cost reduction
- Ammonia consumption is reduced by 10 %
(3) Shorter the required time for proper tuning of control loops during commissioning
- The required time for proper tuning is reduced by 50 %
Functions
(1) Advanced control in DCS
- High reliability
- Excellent control performance by analytical methods
GPC: Generalized Predictive Control
LQR: Linear Quadratic Regulator
- Easy maintenance
Objectives of each function are clear
Tuning tool is available
(2) Applied power plant
- Several Combined Cycle Plants (1,100 deg C, 1,300 deg C) |
