Development of New Desulfurization Agent Suitable for Dry Desulfurization Process at Low Temperature in China

In recent years, the development of new dry desulfurization technology to prevent air pollution has been urgently needed in China. This technology (T-T process) should provide both a high desulfurization rate at lower temperature and useful desulfurization by-products for alkali soil amelioration. In this paper, the combination of zeolite and CaO (Zeolite + CaO) as a new and effective desulfurization sorbent is compared with the conventional sorbent FLASH. The new sorbent gave a desulfurization rate of 72.0% at 473 K, which is lower than the previous temperature. This is thought to be related to increased adsorption of calcium hydroxide resulting from the greater specific surface area of zeolite. In addition, reversing the order of input of calcium oxide and carrier when FLASH and Zeolite + CaO are prepared also increased the desulfurization rate. Both new FLASH and new Zeolite + CaO gave higher desulfurization rates than previous sorbents: 32.4% and 74.9% at 473 K and 623 K, respectively, for FLASH; and 84.1% at 523 K for Zeolite + CaO. This effect is thought to be due to an increase in the specific surface area of sorbent resulting from the input of carrier into a solution in which calcium oxide is dispersed uniformly. Moreover, the value of activation energy indicated that the reaction activity was increased by reversing input order. It was also confirmed that all desulfurization by-products from FLASH, Zeolite + CaO, New FLASH, and New Zeolite + CaO contain gypsum, which is effective for alkali soil amelioration.