Removal Of So2 And No From Simulated Flue Gas Using Cerium-Modified Palm Shell Activated Carbon
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Date
2010-04
Authors
Sethupathi, Sumathi
Journal Title
Journal ISSN
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Publisher
Universiti Sains Malaysia
Abstract
The focus of this research was to study the usage of oil palm shell made activated carbon as a sorbent to remove SO2 and NO gases simultaneously from simulated flue gas. The palm oil industry plays a major role in Malaysian economic especially in enhancing the economic welfare of the population. Despite obvious benefits of this industrial development, its activity contributes to abundant solid waste. Palm shell derived from the fruit bunch of oil palm, is one of the solid wastes. In this study, the conversion of oil palm shells into activated carbon followed by modification with metal derivatives was examined for simultaneous removal of SO2 and NO. The production of palm shell activated carbon (PSAC) was optimized using design of experiment. It was found that the developed design predicted the micropores and surface area of PSAC satisfactorily within the range of the variables studied. The optimum operating condition for preparing the PSAC was 50min of N2 and 90min of CO2 retention time respectively, 500ml/min of N2 and CO2 flow rate and an operating temperature of 1090°C. The prepared activated carbon was tested for its potential of removing SO2 and NO gases from simulated flue gas. The optimized PSAC could only remove SO2 successfully. The maximum sorption capacity of SO2 and NO was 76.60mg/g and 0.72mg/g respectively. Thus in this study, metal derivatives were added to enhance sorption capacity of the PSAC through impregnation method. Metal nitrates such as nickel, cerium, vanadium and ferum were used. It was found cerium impregnated PSAC shows good removal of NO as well as simultaneous removal of SO2 and NO gas. A 10% loading of Ce onto PSAC resulted 121.72mg/g of SO2 and 3.46mg/g of NO sorption capacity per gram of PSAC-Ce. The operating conditions for this optimized sorption capacity are an adsorber temperature of 150°C and feed gas containing 2000ppm SO2, 500ppm NO, 10% of O2, 15% of relative humidity (RH) and with N2 balanced to a total gas flow rate of 150ml/min. A complete breakthrough analysis of operating conditions such as temperature, space velocity, humidity, and feed concentration of SO2 and NO was done. All these factors were influencing the sorption capacity of SO2 and NO onto PSAC impregnated with cerium (PSAC-Ce). A transient study was conducted by introducing stepwise changes to the composition of SO2, NO and O2 on PSAC and PSAC-Ce. Based on this study it was concluded that NO can be removed easily by PSAC or PSAC-Ce, provided SO2 was not introduced into the system because SO2 acts as a competitor to NO removal. The simultaneous removal was also analyzed based on single and binary sorption models. Thermodynamic properties were evaluated and a breakthrough model was fitted to this system to predict the breakthrough curves. The activation energy for SO2 and NO sorption were 7.84 kJ/mol and 19.66 kJ/mol respectively. Finally various types of characterization such as TEM, SEM, EDX, BET surface area, XRD, TGA, FTIR were done to prove the data of SO2 and NO removal using PSAC impregnated with cerium.
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Keywords
The usage of oil palm shell made activated carbon , as a sorbent to remove SO2 and NO gases simultaneously