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Air Quality Control System upgrade for Xcel Energy Services

From 2004-2007, the King plant underwent a complete rehabilitated as part of Xcel Energy's metro emissions reduction project. As part of this project, we were contracted to perform detail engineering for the addition of state-of-the-art air quality control equipment.

The Selective Catalytic Reduction (SCR) is part of the Air Quality Control System (AQCS) upgrade. The boiler equipment is retrofitted with equipment designed to run coal with a net output expected to be 530MW. AMEC supplied engineering and procurement for the SCR system with associated reagent supply equipment to reduce NOx emissions in the flue gas. Components of the project included flue gas-modeling, optimizing the reactor and overall design of the SCR, catalyst, ductwork, support steel design and supply, controls for the SCR system through an addition to the plant DCS system, a new electrical substation supplied as a package unit lifted into the SCR structure, flue gas sampling system and auxiliary components.

Interferences between ducts and structural steel were minimized through the use of 3D modelling system in conjunction with a 3D laser scan model of the existing area. The combined model proved very useful in identifying interferences between the existing steel structures, ductwork, and components that were interlaced with the new SCR and support structure.

The improvements were targeted at significantly reducing air emissions and restoring the King unit to its original electricity output capacity, while extending the life of the plant.

Location:Bayport, Minnesota, US
Client:Xcel Energy Services
Scope:Detail engineering, modeling, scheduling, procurement
Date:2007