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

Abstract

A novel technology for the simultaneous removal of NOx (= NO + NO2) and SOx (= 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 NOx (189 - 335 ppm) and SOx (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 NOx is obtained when the NOx concentration is reduced from 315 ppm to 193 ppm (O3/NO = 0.32). This simultaneous de-SOx and de-NOx technology by PCHP is highly effective and promising for exhaust gas treatment for a glass manufacturing system.

Keywords

• glass manufacturing system
• nox
• denitration
• sox
• desulfurization
• ozone
• plasma chemistry
• nonthermal plasma
• na2so3