An integrated process consisting of Mg(OH)2 –impregnated ceramic foam filters as adsorbent and Mg(OH)2 as scrubbing solution for intensified desulfurization of flue gas

Abstract

Integration of individual unit operations is an efficient strategy for the process intensification. In current study, an integrated absorption/adsorption process is introduced for the flue gas desulfurization. The flue gas was originated from the combustion of a high-sulfur gasoil/naphtha fuel. The adsorbent was prepared by impregnating Al2O3/SiO2 ceramic foam filters with Mg(OH)2 via chemical vapor deposition. The setup included three sections of combustion chamber, water scrubbing vessel and absorption/adsorption reactor. In the latter section, beside adsorption of sulfur compounds on the ceramic adsorbent, Mg(OH)2 solution was being continuously refluxed and sprayed over the flue gas to intensify the desulfurization process. Total sulfur removal decreased by around 3% when Mg(OH)2 solution was substituted with pure water in the final reactor. Impact of important operating variables including temperature, pressure and, initial pH was investigated. Temperature and pressure were altered in the ranges of 30 to 70 °C and 2 to 6 bar, respectively. Results indicated the positive effects of temperature and pressure increase on the sulfur removal. The optimum pH of the reflux solution was around 8. The maximum desulfurization efficiency of the intensified process was 98%. Generally, the results confirmed the effectiveness of the absorption/adsorption integration for the desulfurization process intensification.