Nedim Ganibegović, et. al. International Journal of Engineering Research and Applications www.ijera.com ISSN: 2248-9622, Vol. 10, Issue 7, (Series-II) July 2020, pp. 01-09 www.ijera.com DOI: 10.9790/9622-1007020109 1 | Page Numerical Prediction of Risk Areas for Corrosion Damages in Furnace of the Retrofitted Tangentially Fired Boiler Nedim Ganibegović*, Indira Buljubašić*, Amel Mešić*, Izudin Delić* *Faculty of Mechanical Engineering, University of Tuzla, Bosnia and Herzegovina ABSTRACT The modern project solution, which has been implemented on the coal combustion system in Thermal Power Plant Tuzla Unit 6, has enabled the application of low emission concept of combustion and reduction of ash slugging on walls of combustion furnace, but analysis of the operation of boiler has shown significant deviations of the characteristic operating parameters obtained by the exploitation measurements compared to their design values. Previous CFD analysis that has been conducted on the aero-mixture channel and low emission burner has shown that current system of aero-mixture separation has a complex impact on combustion process inside the furnace. In order to determine the scope of the proper coal distribution in the specific boiler furnace on the combustion process, results of previous CFD analysis in combination with data obtained with classical mathematical models, have been used as inlet data for CFD simulation of combustion process. Obtained results in this paper should enable better understanding of combustion process, determination of critical process parameters that have main impact on efficiency of the boiler and its service life. From CFD results it’s clear that shape and position of flame depends on operating mills configuration and coal rate distribution per coal burner height. Keywords - pulverised-coal boiler, coal combustion process, NO X emissions, fireside corrosion. --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 18-06-2020 Date of Acceptance: 06-07-2020 --------------------------------------------------------------------------------------------------------------------------------------- I. INTRODUCTION In the coal-fired power plants, a big challenge is improvement of combustion process enforced by environmental concerns. Regulations and common public pressure for reducing NO X and SO X emissions become stricter and meeting them must be achieved by both new and old production units. The big challenge for the electricity producers from coal-fired power plant will be to ensure flexible operation due to increasing share of renewable sources of energy in the market. That means that coal units have to adapt to market needs and work with increased load variations during the day. Working with changing load requires constant monitoring and control of the operating parameters of the boiler in required intervals in order to maintain high efficiency and required levels of gas emissions. It is currently possible to achieve the required quality of exhaust gasses with primary and secondary measures. Use of a low-emission burner as a standard primary NO X reduction measure can also be applied to existing boilers. This was done by retrofitting during boiler revitalization. There are a number of operational problems of coal-fired boilers, which are suspected to be caused by non-uniform combustion in the furnace [1]. One source of non-uniform combustion is uneven distribution of fuel inputs to the furnaces. The optimization process for emission reduction can be done by optimizing the amount and distribution of fuel and air supplied to the boiler [2]. Homogenous temperature distribution of flue-gas in the boiler furnace promotes lower emissions of NO X , CO, and minimizes total organic carbon (TOC) content in ash. A temperature measurement can also be applied to verify the results of computational fluid dynamics (CFD) modeling [3]. Results of CFD modeling [4] can be used at the stage of the combustion process optimization to provide complete information about the process. A comprehensive large-scale furnace CFD model should be capable of properly predicting trends in NO X reduction by means of primary [5] and secondary [6] methods. CFD modeling has been extensively applied to provide information on the complex phenomena in tangentially fired boiler [7– 9]. In [7], comparison between the boilers combustion characteristics was carried out based on the CFD simulation. In [8], different operation regimes of pulverized coal furnace have been investigated with the CFD code. The simulation results show a good agreement with the measurement. Similar purpose was achieved in [9]. Additionally, a grid refinement study was performed. The flow field and temperature RESEARCH ARTICLE OPEN ACCESS