ZHANG Yanwei;CAI Xiaofeng;LV Yanyan;WANG Jie;FAN Junjie;

• 1:Shanghai Industrial Boiler Research Institute Co.
• 2:Ltd.
• 3:School of Environment and Architecture
• 4:Shanghai University of Technology

Abstract：

Thisarticle takes a 91 MW coal-fired hot water boiler from a certain user in Shenyang as the research object. Two calculation software are combined to simulate the conventional operating conditions of the boiler and the power field, temperature field, oxygen concentration distribution, and NO_x generation of the flue gas above the grate after two ways of denitrification transformation. The comparison is made between the non flue gas recirculation, the circulating flue gas entering the grate above the six small air chambers, and the circulating flue gas entering the grate from the first and second air chambers, respectively There are three different working conditions for the secondary air inlet to enter the furnace in a graded manner. The simulation results show that: When the boiler operates under conventional operating conditions, there are obvious uneven mixing areas in the flue gas, high average and local temperatures of the flue gas, high and uneven distribution of NO_x concentration; The circulating flue gas enters the upper part of the grate from the 6 th small air chamber, causing the uneven mixing area of the flue gas to become smaller and not completely disappear. The average temperature and local high temperature of the flue gas have slightly decreased, and the NO_xconcentration has decreased and the uneven distribution has improved; The circulating flue gas enters the furnace in stages from the primary and secondary air vents, and the uneven mixing of flue gas disappears. The average temperature of the flue gas is reduced by about 150 ℃ compared to conventional operating conditions, and the distribution of NO_x is uniform. The NO_x concentration at the furnace outlet is reduced by about 170 mg/m~3 compared to conventional operating conditions. The numerical simulation results of the conventional operating conditions of the boiler are completely consistent with the actual furnace tests, and the simulation results of flue gas recirculation can provide theoretical support for the boiler denitrification transformation.

Key Words： layer combustion boiler;numerical simulation;flue gas staged recirculation;power field;temperature field;NO_x generation amount

Abstract:

Keywords:

Foundation:

Authors: ZHANG Yanwei;CAI Xiaofeng;LV Yanyan;WANG Jie;FAN Junjie;

DOI: 10.13226/j.issn.1006-6772.LC23101601

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