Synergistic effect of additives and blend on sulfur retention, NO release and ash fusibility during combustion of biomass briquettes

ABSTRACT

Even though biomass is carbon-neutral renewable energy, the utilization of biomass results in sulfur oxides (SO_x), nitrogen oxides (NO_x) and particles emissions. Biomass briquetting and doping with additives are potential methods to ease these emissions. However, additives may increase the price for biomass application. Hence, another method is mixing different kind of biomass which possesses significant difference in ash composition, i.e. using synergistic effect to ease these emissions. In this study, the effect of blending of tree bulk and wheat straw and additives on SO₂, NO emissions from briquettes combustion were studied. Experimental results indicate that the emission of SO₂ and NO from the mixed briquettes would decrease due to the synergistic effect. An appropriate weight mixing ratio between tree bulk and wheat straw was recommended. The method of mixing raw materials would potentially save additives and reduce the cost of biomass briquettes. The SO₂ and NO emission would further decrease and the ash fusibility could be improved obviously for the mixed briquettes modified by CaO, CaCO_3, and NH₄H₂PO₄. The NO emissions for the briquettes are much lower during the combustion temperature of 800°C 1000°C. This study may contribute to modification, additives, clean combustion, and economy for the utilization of biomass fuel.

KEYWORDS:

• Biomass briquettes
• SO₂
• NO
• ash fusibility
• synergistic effect

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

This study was supported by the National Natural Science Foundation of China [51206096]; College Independent Innovation Fund of Jinan [201401275] and Science and Technology Development Plan Project of Shandong Province [2016GGX104005].