Effects of Catalysts on Pyrolysis and Liquefaction of Tannery Sludge

Three inorganic compounds, K₂CO₃, K₂SO₄, KCl have been investigated with regard to their catalytic effects on pyrolysis of tannery sludge by thermal analysis experiments. The influence of catalyst categories and dosage on sludge pyrolysis were studied by the comparison and analysis of the TG ( thermogravimetry ) and DTG(derivative thermogravimetry) curves derived from tests of differential thermal balance of untreated sludge and sludge respectively mixed with three inorganic compounds of certain scale. And the catalytic effect on product distribution and oil yield was studied with changing the dosage of catalyst by using experimental installation which was designed for direct thermochemical liquefaction of sludge.The results show that the catalytic effect of the potassium compounds follow K₂CO₃>K₂SO₄>KCl, and 2%wt K⁺ of sludge weight is chosen as the optimal dosage of the catalysts. The maximum of oil yield was achieved at the condition of 2%wt of K₂CO₃ with the technique of direct thermochemical liquefaction of sludge, it matched with the result of TG analysis.