Under microaerobic conditions closed calcium carbide furnace exhaust COS gas adsorption purification
|School||Kunming University of Science and Technology|
|Keywords||carbide furnace gas carbonyl sulfide modified activated carbon adsorption purification|
This thesis aimed to research adsorption purification of carbide furnace gas. The emphasis of article included adsorption performance of COS components, by supported alkali modified activated carbon and transition metal phthalocyanines modified activated carbon. Firstly, experiments were conducted to select carriers and active components of absorbents. Secondly, single factor adsorption experiments of two different absorbents were studied. Thirdly, N2 adsorption-desorption(N2-BET), scanning electron microscope(SEM), energy dispersive spectrometer(EDS), X-ray photoelectron spectroscopy(XPS) and temperature programmed desorption(TPD) were used to characterize catalysts before or after adsorption reactions. Finally, reaction mechanisms of absorbents were inferred by basic experiments and characterization.The carrier was AC4 in researches. The experiment results compared with a previous study, supported alkali modified activated carbon enhanced the effective purification capacity before COSpurification through point(C/Co=10%). And KOH modified activated carbon the adsorption capacity of penetration 13.694mg. g-1.The purification capacity for COS gas reached the maximum when theKOH modified activated carbon have reacted in the U-shape reactor at 60℃reaction temperature with 1.0% oxygen content. Furthermore, SEM-EDS distribution indicated that the result of adsorption became obviously better by the change of pore structure of modified activated carbon and the form ation of surface active materials,and the XPS results showed theCOS mightbe absorbed by the interaction with catalytic purification on modified activated carbon and O2 to form the sulfate and element sulfu.TheCOS purification results showed that Cu/CoSPc/KOH modified activated carbon could get a more excellent absorbent. For a certain concentration of KOH,0.1 mol·L-1 concentration of Cu2+,100mg·g-1 of CoPcS/KOH proportion,110℃of dryness temperature and 350℃of cremation temperature are optimum conditions for preparing modified activated carbon. Volume space velocity of 1252h-1, oxygen content of 1.0% and adsorption temperature of 60℃are suitable conditions in adsorbing reaction phase. The comparative study showed that Cu/CoSPc/KOH modified activated carbon enhanced the effective time 2.5 times before COS purification through point, than KOH modified activated carbon. XPS demonstrated that the instruction of CoSPc could improve Cu loading effectively on the carrier, and more conducive to COS gas in Cu/CoSPc/KOH modified activated carbon on the chemical reaction occurred in CuS and other compounds to improve the removal efficiency of purification..The TPD experience result revealed that there are two kind of active species on the surface of modified activated carbon. One is independent of alkali content and transition metal phthalocyanines whera the another active species has a strong relationship with the content of KOH.The surface base of modified activated carbon has change remarkablely when KOH、CoSPc and Cu2+are add,and active species surface will also change the distribution center to raise the number of modified activated carbon and the strength of active centers, clean removal of COS to significantly improve the results.Gas composition of carbide furnace off-gas was analysis and determination in Yunwei Corporation.Onsite experiments were conducted to investigate the practical purifying efficiency of modified activated carbon on carbide furnace off-gas.10% KOH activated carbon and activated carbon modified Cu/CoSPc/KOH modified activated carbon adsorption can better adsorption purification carbide furnace off-gas to reach adsorption breakthrough time was 280min and 630min, both modified activated carbon have good prospects in engineering applications.