ABSTRACT
With the optimization of China's energy structure, biomass as a carbon-neutral, renewable energy source has a substantial development and utilization value. However, the current biomass fuels are applied mainly by direct combustion, which has the problem of low thermal efficiency. In this paper, we primarily investigate the share of water vapor in the flue gas produced by biomass combustion and the effect of its vaporization latent heat recovery on the improvement of thermal efficiency. Through theoretical calculations, the share of water vapor in the flue gas generated by the combustion of three biomass fuels was derived; experimental tests were conducted using a biomass vaporization experimental combustion bench containing a condensing heat exchanger to investigate the effects of different factors on the recovery of waste heat in the flue gas of pine fuel combustion. The results showed that the thermal efficiency improvement was about 6%-9% under several operating conditions measured experimentally, and the thermal efficiency improved by latent heat was significantly higher than that by sensible heat, indicating that recovering latent heat from biomass boilers to improve thermal efficiency has excellent potential and practical application.
