The boilers lose heat through various means, this statement refers to various ways in which heat is released or transferred, such as the emission of hot gases from chimneys, the disposal of hot wastewater, and the transmission of heat from heated surfaces. This study focuses on a chimney originally designed for a 15-ton/hour, 16-bar boiler. The issue with the chimney is that it experiences a high accumulation of carbon particles. In an effort to address the issue, the chimney has been re-engineered to minimize the build-up of scale which impacts the boiler's performance. It is specifically designed for use in boiler chimneys and features a hatch. The goal of this project is to decrease the size of the cross-sectional area of this particular section in order to enhance the flow of flue gases.