Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
EFFECTS OF CORROSION INCIDENCE ON A BIOMASS STEAM GENERATOR UNIT: A CASE STUDY
Submission Author:
Fabiana de Marqui Mantovan , RS , Brazil
Co-Authors:
Fabiana de Marqui Mantovan, Eduardo Burin, Edson Bazzo, Joel Gustavo Teleken, Adriana Ferla de Oliveira, RAFAEL WELTER, Cristian Giliard Zapalai
Presenter: Fabiana de Marqui Mantovan
doi://10.26678/ABCM.COBEM2021.COB2021-1225
Abstract
This paper presents the results of a case study whose objective was to evaluate the effects resulting from the incidence of corrosion on the gas side of the heat recovery section of a biomass steam generating unit. The equipment consists on a grate type biomass steam generator with capacity to produce up to 40 t/h of saturated steam (15 bar) and equipped with an economizer and air preheater. During the first four years of operation, the equipment was operated at partial loads (<65% load) and with stoppages on weekends, and during this period a strong development of corrosion was observed in the economizer and air preheater, culminating in the complete degradation of these two components. In this context, the first step consisted of characterizing the biomass used as fuel. Then, the operation of the steam generating unit was monitored based on data obtained from the supervisory system, unburned carbon content in ash, biomass moisture and measurements made with a flue gas analyzer model TESTO 340. The energy diagnosis of the equipment was performed based on the indirect method of the ASME PTC 4 (2013) standard, and the calculations were performed using the Engineering Equation Solver (EES) software. Among the results presented, we highlight the significant reduction in the thermal efficiency of the equipment (-5.0% in relation to the design point condition) caused especially by the presence of air infiltration, partial combustion of the fuel and the absence of pre-heating of the feed water and primary combustion air. The authors suggest, in this context, the importance of monitoring of the elemental composition of the fuel burned, especially with regard to the content of chlorine and sulfur, as well as monitoring the temperatures that occur in the heat recovery section in order to avoid the incidence of moisture condensation on metal surfaces.
Keywords
Steam generators, Biomass, corrosion, Thermal Efficiency
