Simultaneous sulfur dioxide and mercury removal during low-rank coal combustion by natural zeolite

Sulfur dioxide (SO₂) and trace metal such as mercury emission during combustion of low-rank coal cause a significant impact on the environment and health. Flue gas at coal-fired power stations is one of the main sources for the emissions of SO₂ and mercury metal. Low-cost and sustainable technologies for the removal of SO₂ and mercury from flue gas have become increasingly important nowadays. This paper presents the study of simultaneous removal of SO₂ and mercury over natural zeolite as an adsorbent in briquette and pulverized. The research is focused on evaluating adsorbent to coal optimum ratio towards adsorption performance on SO₂ and mercury removal. The experiments on the removal of SO₂ and mercury were carried out using horizontal electric furnace with different combustion temperature and adsorbent ratio. SO₂ in the flue gas as the result of the combustion process which exits from the outlet was analyzed using Gas Combustion and Emission Analyzer (E4400, E-Instrument). Mercury metal residues in the bottom ash were analyzed using NIC Mercury SP Analyzer. An increasing zeolite adsorbent SO₂ content in flue gas decreased. The optimum SO₂ removal was determined on 4% zeolite adsorbent ratio. It also has been found that 8% natural zeolite ratio to low-rank coal show optimum condition to adsorb mercury for all temperature condition for both briquette and pulverized conditions.