Optimizing post-combustion nitrogen oxide and sulfur dioxide reductions and improving combustion efficiency in coal fired boilers

摘要

A method for increasing the nitrogen oxide emissions by either removing or modifying fuel rich nitrogen oxide (NO_x) reduction processes thereby improving combustion efficiencies especially with low volatile low sulfur coals, and remove unburned carbon, reduce sulfur dioxide and reducing carbon dioxide emissions, while using post-primary combustion urea or ammonia injection with or without a reburn fuel NO_x reducing process to restore NO_x to regulated emission levels. Furthermore, adding lime or limestone to the urea or ammonia solution to further reduce SO₂ and to increase the concentration of the carbon free fly ash to cementitious concentrations. Furthermore, by proper number and disposition of the injectors in the post combustion zone and by further water diluting the mixture, this NO_x reduction process is effective at substantially higher gas temperatures than conventional Selective Non-Catalytic NO_x Reduction and with no ammonia slip. This method significantly increases the profitability of power plants.