Studies On Absorption Of Low Concentration SO₂ By Activated Carbon Fiber And Regeneration By Microwave Radiation

The absorption and devulcanization of low concentration SO₂ by activated carbon fiber under different work condition is studied in the paper. The SO₂ is desorbed by irradiating the saturated activated carbon fiber by microwave. By doing so, activated carbon fiber can be reused. The mechanics of desorption is also studied.The rate of the absorption of low concentration SO₂ can be described by Bangham equation. Adsorption equilibrium can be well described by the Freundlih equation and Langmuir equation. Activated carbon fiber is warmed quickly in the microwave field and the maximum is achieved in about 200 seconds. The characteristic of warming-up of new activated carbon fiber and the saturated activated carbon fiber is the same in the microwave field. Four stages are divided: linear warm-up stage,negative exponential stage,constant temperature stage and linear warm-down stage. The following factors influencing the warming-up of fiber are listed according to the degree of influence: Loss of activated carbon fiber increased linearly in 300 seconds and then there is no loss .No more than 7% of activated carbon fiber is lost after 7 times of irradiations.The high power microwave can desorb more SO₂ than the low power ones. The high power is good to the desorption of SO₂. SO₂ is desorbed completely in 600 seconds when the power of microwave is above 500W and the maximum is achieved in about 100 seconds. The final desorption rate is 95%. More gas is beneficial to the desorption which can shored the desorption time. The quantity of activated carbon fiber influences the time and the peak value. The final desorption rate is nor influenced by the quantity of activated carbon fiber. In experiments, the best operation is irradiating time 240s, power of microwave 700W, quality of activated carbon fiber 1000mg and carrier gas flux 0.08 Nm³/h. adsorption capacity of activated carbon fiber is obviously improved, the reclamation rate is maintained at 93% and the loss of activated carbon fiber is within 10%.According to the results, microwave desorption can shorten the time, reduce the loss of the activated carbon fiber, benefit the reuse of SO₂, increase the concentration of SO₂. in all the microwave desorption is practical,economical and worthy of being studied.