Mathematical Modeling of a Locally Fabricated 2-Pass Fire-Tube Horizontal Return Tubular Boiler (HRTB) From First Principle of Material and Energy Balance

Abstract

This research presents the mathematical modeling of a locally fabricated two-pass fire-tube horizontal return tubular boiler (HRTB) based on first principles of material and energy balance. Utilizing MATLAB/Simulink for simulation, the study analyzes the thermal dynamics of the boiler system under varying operational conditions. Key findings include a rapid increase in furnace temperature from an initial 210 K to a steady-state of approximately 820 K within 25 minutes, attributed to the efficient combustion of natural gas. The furnace wall temperature rose from 298 K to a steady state of about 590 K, demonstrating effective heat transfer from the flue gases to the surrounding water. The temperature profiles for both the first and second pass tube walls indicate that heat transfer is maximized in the first pass, with a notable gradient observed. Additionally, the feed water mass flow rate exhibited a steady increase, reaching 92 kg/hr, indicating a rapid conversion of water to steam. The chimney temperature rose from 300 K to 590 K, highlighting the effective draught necessary for combustion. Overall, the results underscore the importance of fuel type and boiler design in optimizing thermal performance.