Abstract: In order to systematically analyze the energy and material consumption characteristics of double tower double cycle desulfurization system, testing the power consumption, water consumption and limestone consumption at the exit of double tower double cycle desulfurization systems in 53 ultra-low emission units. And study the effects of inlet SO₂ concentration, liquid gas ratio, pH value and Ca/S ratio on the energy and material consumption characteristics of unit mass SO₂ removal. The measurement results indicate that the the energy consumption of SO₂ removal accounts for 55%~80% of the total removal cost, while the power consumption of circulating slurry pump accounts for 50%~70% of the total energy consumption. The energy consumption per unit of SO₂ removal in primary and secondary absorption tower decreases with the increase of inlet SO₂ concentration, and the energy consumption per unit of SO₂ removal in secondary absorption tower is much higher than that in primary absorption tower, The energy consumption per unit of SO₂ removal in the first and second stage absorption towers decreased first and then increased with the increase of pH value. Which shows that in order to reduce the energy and material consumption per unit mass of SO₂ in the double tower double cycle desulfurization system, the SO₂ concentration at the inlet of the primary absorption tower should be controlled at 4 000~6 000 mg/m³, and the slurry pH value should be controlled at about 5.2; The concentration of SO₂ at the inlet of secondary absorption tower should be controlled at 1200 mg/m³, and the pH value of slurry should be controlled at about 6.0.

Key words: double tower double cycle desulfurization system, energy consumption, material consumption, pH value, liquid gas ratio