Testing new SCR Installations

TRAX can put together a simulation of your SCR and use it to thoroughly test all of the control loops and operator screens. The result is a control system that is checked out far more rigorously than normal, and one that "hits the ground running" with all interlocks and permissives functioning correctly. This type of testing will drastically reduce commissioning time, resulting in significantly shorter plant outages.

Tuning SCR Control Loops

By testing the controls against a dynamic model, gains for feedback loops can be tuned and functions or tables for feedforward loops can be accurately calculated. After this, all that is generally required is some minor fine-tuning when the controls are installed in the plant.

Programming and Debugging DCS and PLC Controls

TRAX has experience programming and debugging controls in all major types of DCS and PLC hardware. Furthermore, we can write or debug interfaces connecting PLC and DCS hardware.

Testing Control System Behavior During Transient Operation

TRAX can effectively test controls from cold conditions, through SCR warmup, and on to full load. Controls are tested during fast and slow load ramps, and through major plant upsets (such as a master fuel trip). TRAX also has the capability to test the controls through any type of equipment malfunction including pump cavitation, equipment tripping off line, valves failing open or closed, SCR poisoning and inadequate soot blowing to name just a few. In the end, your control system will be better able to provide maximum performance.

SCR Control System Functions

• Safely unload liquid ammonia from trucks or rail cars
• Maintain maximum, safe warmup rates for catalyst and SCR reactor
• Provide pressurized ammonia via pumps or vaporizers
• Establish sufficient dilution air flow to carry ammonia to the flue gas
• Maintain dilution air temperature
• Regulate the flow of ammonia based on plant load
• Further control ammonia flow to maintain NO_x concentration at setpoint
• Schedule catalyst soot blowing
• Switch between redundant equipment as necessary
• Provide safety interlocks to interrupt ammonia flow in case of insufficient flue gas flow, low catalyst temperature, master fuel trip, etc.