BOILER UNIT OPERATION METHOD Russian patent published in 2023 - IPC F22B33/18 

FIELD: thermal power engineering.

SUBSTANCE: invention can be used in natural gas-fired boilers. A method of operation of a boiler unit in which feed water, organic fuel and air are supplied to the boiler. Combustion products are formed in the boiler furnace, and superheated steam is generated. Superheated steam and combustion products are sequentially cooled in a steam superheater, a water economizer, an air heater and a condensing surface heat exchanger. The blowdown water removed from the boiler is directed to a continuous blowdown expander, where part of the blowdown water boils to form secondary steam, which is removed from the continuous blowdown expander via a steam line. The exhaust combustion products, cooled below the dew point in the condensation surface heat exchanger, are heated in the waste heat exchanger with the blowdown water that has not evaporated in the continuous blowdown expander and vented into the atmosphere. The boiler installation is additionally equipped with a steam nozzle installed in the boiler furnace and connected to the continuous blowdown expander via a steam line, through which secondary steam generated from blowdown water in the continuous blowdown expander is sprayed into the active combustion zone of organic fuel at a pressure of 0.2-0.25 MPa and amount of 5-8% of the organic fuel flow to the boiler. The outlet part of the nozzle is made in the form of a de Laval nozzle.

EFFECT: formation of thermal and fuel nitrogen oxides is reduced by reducing the temperature of combustion products and excess oxygen in the zone of active combustion of organic fuel.

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