EMISSIONS OF GASEOUS AMMONIA AND PARTICULATE CONTAINING AMMONIUM-COMPOUNDS FROM A SMELT DISSOLVING TANK

During a stack survey of the smelt dissolving tank at Peace River Pulp , gaseous NH3 and particulate containing ammonium compounds were found . A study was conducted to examine the cause of such emissions. The re sults confirmed the presence of NH3 in the vent stack, smelt and in al l liquor samples analyzed. NH3 exists in the vent stack due probably t o its liberation from the green liquor in the dissolving tank and from entrained liquor droplets, and its entrainment in combustion gases fr om the recovery boiler through smelt spout openings. The particulate w as found to contain mostly (NH4)(2)SO4 and organic ammonium compounds, which were probably formed as a result of reactions between NH3, SO2, O-2, H2O and organic gases in the vent stack. The study also suggests that NH3 odour, which has been noticed occasionally in causticizing p lants, is likely caused by the decrease in the solubility of NH3 in wa ter as the temperature and pH of the solution increase.