Comprehensive rehabilitation of EPR II

A comprehensive rehabilitation project for the EPR II electric power plant consisted (among others) of a complete replacement of the equipment in the boiler room for three blocks. Working as a subcontractor for its partners IVITAS, a.s. and Vitkovice power engineering, MORE delivered a basic design of firing system for lignite-fired boilers in accordance with the written parameters it was given. In 2016, the realization of all three blocks finalized and guarantee tests were performed, which confirmed the success of the project.

Production block parameters

• Block rated capacity: 250 MW_e
• Controled power range: 50 – 105%
• Minimum boiler power without use of stabilization burners 45%
• Main fuel - Czech brown coal with LHV (NCV) ranging from 8.5MJ/kg to 11MJ/kg, moisture content (raw) 31% - 34%, ash content (raw) 35% - 46%

Boiler parameters

• Flow rate of superheated steam: 660.4 t/h
• Maximum flow rate of superheated steam: 669.4 t/h
• Pressure of superheated steam: 18.26 MPa
• Temperature of superheated steam: 575 °C
• Pressure of reheated steam: 3.65 MPa
• Temperature of reheated steam: 580 °C
• Temperature of supply water: 251 °C
• Performance range without stabilization and complying with the specific parameters: 50 – 105 %
• NOx emission limit 200 mg/m3 (standard conditions and reference content O2 6%), utilizing the primary measures to reduce NOx emissions
• CO emission limit 250 mg/m3 (ref. conditions)

Our responsibility in the project

Our task was to propose a boiler and firing system design and create a foundation for the basic design, including:

• A design of the geometric arrangement of the furnace
• A plan of the primary measures to reduce the NOx production and zoning of the air and fuel
• A design of the combustion mode to fulfil the requirements of the guaranteed parameters within the entire range of performance and operation without slagging
• Testing the concept of the combustion chamber, combustion design, and denitrification with the help of the CFD method
• Creation of the technical concept for the supply of mills and pulverized coal classifiers
• Design a new solution for the classifier of the pulverized coal and testing the concept with the help of the CFD method
• A design of pulverized coal pipes and pulverized coal burners
• A design of flue gas and air tracks of the boiler, including fans
• A design of the tract for flue gas recirculation, including a fan
• Development of the specifications for the field instrumentation of the MaR system for beater wheel mill circuits, including the flue gas and air tract of the boiler
• A project of the algorithms for beater wheel mill circuit operation, air mode and flue gas recirculation
• A design of the system to reduce unburned residues of cinder by flue gas recirculation in the slag heap, testing of the concept with the help of the CFD method
• An analysis of unsteady and emergency conditions of the boiler and proposed measures
• A design of the system to monitor combustion stability, a project of algorithms and installation into the control system
• Creation of the specifications for related professions
• Setting and optimization of the boiler combustion modes

We applied our know-how gained over the years and managed to decrease emissions of  NO_x below the limit of 200 mg/m³ under reference conditions without using secondary measures for NO_x reduction.  To achieve this result was not an easy task, and is therefore greatly valued by us as professionals.