Pilot-scale exhaust gas treatment for a glass manufacturing system using a plasma combined wet chemical process

抄録

A novel technology for the simultaneous removal of NO_x (= NO + NO₂) and SO_x (= SO₂ + SO₃) in the flue gas of a glass manufacturing system is described using a plasma-chemical hybrid process (PCHP). The exhaust gas is produced by combustion of liquefied natural gas and contains both NO_x (189 - 335 ppm) and SO_x (109 - 183 ppm). Lowering the flue gas temperature from more than 200 °C to less than 150 °C is required for effective NO oxidation (80% efficiency) to NO₂ by ozone gas injection. Therefore, a mixture of ozone and water are sprayed by compressed air from the three-fluid spray nozzle into the exhaust duct. The ozone gas is prepared using an electrical discharge-induced nonthermal plasma apparatus. In addition, almost all of the SO₂ is absorbed by a NaOH absorbent resulting in the generation of Na₂SO₃. Furthermore, reduction of the water-soluble NO₂ by Na₂SO₃ to N₂ affords Na₂SO₄, which can be reused as glass material. The highest removal efficiency of 39% for NO_x is obtained when the NO_x concentration is reduced from 315 ppm to 193 ppm (O₃/NO = 0.32). This simultaneous de-SO_x and de-NO_x technology by PCHP is highly effective and promising for exhaust gas treatment for a glass manufacturing system.