A novel method for removing NOx from simulated marine exhaust gas in wet absorption system using Na2SO3/THS composite solution

Since it is difficult to deal with high-concentration nitrates in scrubbed wastewater onboard vessels, the application of traditional wet denitration technology is limited to some extent. Here a novel method for removing pre-oxidized NO x by using Na 2 SO 3 /THS composite solution is proposed with the aim to obtain high NO x absorption efficiency and low nitrate concentration in scrubbed wastewater simultaneously. The effects of Na 2 SO 3 concentration, THS concentration, NO x oxidation degree, coexistence of SO 2 and O 2 in flue gas, initial pH value and temperature of absorption solution on denitration performance were discussed in detail. The results showed Na 2 SO 3 could reduce NO x to nitrate, nitrite, and N 2 . The addition of THS could promote NO x absorption greatly by forming complexes with SO 3 2− . When initial NO x concentration was 1000 ppm with a NO x oxidation degree of 50%, O 2 concentration was 8%, Na 2 SO 3 and THS concentrations were 25 and 20 mmol/L, a NO x absorption efficiency of 87% could be achieved, while nitrate and nitrite concentrations were 32.97 and 14.19 mg/L, respectively.