Systems and methods for nitrogen recovery from a gas stream

A method of recovering ammonia from a gas stream, the method comprising:

• introducing sulfur dioxide vapor into water to produce aqueous sulfurous acid;
• introducing the aqueous sulfurous acid into a gas stream comprising nitrogenous compounds to produce ammonium ions, sulfurous acid ions, and a nitrogenous liquid;
• introducing an oxidant into the aqueous sulfurous acid or the nitrogenous liquid to oxidize a predetermined amount of the sulfurous acid ions to sulfate ions;
• and
• collecting the nitrogenous liquid comprising remaining sulfurous acid ions, the ammonium ions, and the sulfate ions.

A system for removing nitrogenous compounds from a gas stream, the system comprising:

• a source of sulfur dioxide vapor;
• a source of a gas stream comprising nitrogenous compounds;
• a source of water;
• a source of an oxidant;
• a reaction subsystem comprising at least one absorption chamber, a treated gas outlet, and a product outlet, the reaction subsystem fluidly connected to the source of the sulfur dioxide vapor, the source of the gas stream, the source of the water, and the source of the oxidant, and constructed and arranged to combine the sulfur dioxide vapor, the gas stream, the water, and the oxidant;
• a solids-liquid separator fluidly connected downstream of the reaction subsystem through the product outlet, the solids-liquid separator comprising a solid product outlet and liquid product outlet;
• a temperature control subsystem configured to maintain a predetermined temperature range within the reaction subsystem;
• an oxidation control subsystem configured to maintain a predetermined oxidation reduction potential (ORP) within the reaction subsystem;
• and
• a recirculation line extending between the at least one absorption chamber and a recycle inlet of the reaction subsystem, the recirculation line constructed and arranged to reintroduce water vapor and residual gases not absorbed in the at least one absorption chamber to the reaction subsystem.