Removal of So2 in dry fluidized and fixed bed reactors using granular activated carbon

Dissertant

Jabbar, Umar Ali

Thesis advisor

Ibrahim, Niran Khalil

University

University of Technology

Faculty

-

Department

Department of Chemical Engineering

University Country

Iraq

Degree

Master

Degree Date

2010

English Abstract

Flue gas desulfurization process has been studied using granular activated carbon in bubbling fluidized bed reactor.

For the sake of comparison, fixed bed configuration has been also studied at the same operating conditions as those used in fluidized bed reactor.

The reactor was constructed from QVF column of 2.54 cm inside diameter and 50 cm long, with a height of granular activated carbon bed of 12 cm that gave a weight of 30 gm.

The carbon particles used have a mean particle size of dp = 1.09 mm.

All experiments were made at atmospheric pressure and the effect of three process variables, namely temperature 30 ≤ T ≤ 80 oC , inlet SO2 concentration 500 ≤ Co ≤ 2000 ppm, and flue gas flow rate 2.5 ≤ Q ≤ 30 /min were well investigated.

For bubbling fluidization, the results showed that the SO2 removal efficiency increases with increasing reaction temperature in a manner so that the maximum removal efficiency was achieved at the highest operating temperature of 80 oC.

Also, it was noted that the removal efficiency decreases with increasing the inlet SO2 concentration within the range of temperatures studied.

The effect of flue gas flow rate on the desulfurization activity was in two ways; an increase in the removal efficiency with increasing gas flow rate was observed below flow rate = 7.5 /min, which is the region of fixed bed operation, while a decrease in the efficiency was observed upon any increment in the gas flow rate beyond the 7.5 /min, which is the region of high velocity fixed bed operation, and fluidized bed operation.

For bubbling fluidization regime the highest removal efficiency obtained was 94.94%, at Q= 15 /min, T= 80 oC, and Co= 500 ppm.

For fixed bed reactor, a similar trend of the effect of temperature and inlet SO2 concentration on the average removal efficiency as those observed in bubbling fluidization was obtained.

However, an optimum value for the flue gas flow rate, Q=7.5 /min was observed corresponding to the highest removal efficiency of 99.32% at T= 80 oC, and Co= 500 ppm.

Bed viodage was correlated with the velocity in fluidized bed using the form of: With correlation coefficient (R) = 0.973.

After that, this correlation along with the obtained results of desulfurization efficiencies for fluidized bed reactor, were used to suggest another empirical correlation in the form of: ηav = 1 Y = 1 = 179.7090 (exp ) ( The values of the constants were calculated using STATISTICA software and the experimental results are well correlated with the proposed form with a correlation coefficient, (R) =0.989.The equation above is valid for flow rates of (13.5-30) /min , T (30-80) oC, and initial concentration of SO2 of 500 ppm.

A reaction rate equation was proposed for the oxidative desulfurization reaction as it being the rate controlling step in the region of flue gas flow rates at or above 7.5 /min.

Then, the kinetic parameters, reaction rate constant (k) and activation energy (E), were obtained based on the experimental results using differential analysis of integral reactor technique.

The resulted value of apparent activation energy was 2.981 kJ/mol.

The results of the comparison between the two reactors indicated that lower conversion is obtained in a fluidized bed than in fixed bed over the range of conditions studied.

Main Subjects

Chemistry

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Language

English

Data Type

Arab Theses

Record ID

BIM-305057