Design and CFD modeling of gasifier stove combined with heat exchanger for water heating application

Abstract

Manufacturing industries use a huge amount of power to heat water. The ability to control pollutant gas species released from the company by improving the efficiency of combustion reduces global warming and energy bills associated with water heating. In this study, computational fluid dynamics (CFD) thermal analysis of a biomass gasifier and heat exchanger combined system has been used to study the effect of the concentration of species, such as CH4, CO2, and CO, on the gasification temperature. The power consumed by boilers for water heating in industries, hotels, restaurants, and other domestic hot water heating is, to some extent, to substitute by a combined system. The model and syngas energy analysis of the integrated system was investigated by assuming a eucalyptus wood chip as fuel from the literature with 5%wb ultimate and 10% proximate values to analyze the gasification performance. The reactor was designed to supply syngas gas energy through the pipe. The gasification system was investigated at temperatures ranging from 298 to 990 K. This range of temperature in the gasifier is enough for water heating applications. The CFD model is developed and validated with the experimental results obtained in the literature. Several parameters, such as syngas molar composition and mass fraction, lower heating value of biomass, gasifier efficiency (67.3%), biomass energy, product gas energy, energy gain by the heat exchanger, and hot water outlet temperature, were examined by varying temperature. As the result shows, the species concentrations in the gasifier vary with temperature and gasifying agent. To optimize the transfer of heat from the heat exchanger tube to cold water, the syngas circulation time inside the inner tube should be increased by making the inner tube-shaped zigzag.