Keywords: 
• magnesium oxide /
• flue gas desulfurization /
• bubbling reactor /
• industrial coalfired boiler

Abstract: The reactivity of the calcium carbonate, magnesium oxide and magnesium oxide/magnesium sulfate were compared using laboratoryscale bubbling reactor, and the result confirms that the high concentration of magnesium sulfate in desulfurizing liquid was an important factor for magnesium oxide to gain higher desulfurization efficiency than calcium carbonate. Then the relationships between desulfurization efficiency and several factors were studied, including flow rate of the simulated flue gas, concentration of magnesia absorbent and magnesium sulfate, concentration of sulfur dioxide in the flue gas, and temperature of the absorption liquid etc. The results indicate that the whole desulfurization process can be divided into two parts according to the pH value of absorption liquid. The desulfurization efficiency increased with the increase of concentration of magnesium sulfate; and decreased with the rise of flue gas flow rate or concentration of sulfur dioxide. The temperature and concentration of magnesia absorbent have no obvious effect on the desulfurization efficiency. It can be concluded that magnesium desulfurization process is controlled by the mass transfer of sulfur dioxide at the gasliquid interface, especially the transfer of its hydrolyzate in liquid film.