Patent ID: 9625176
Date: 2017-04-18
CPC Classifications: F24H,F27B,Y02B

Claim:
1. A method of combusting hydrocarbon fuel to form combustion products in which nitrogen dioxide (NO2) is converted to nitric oxide (NO), formation of NO2 from NO is hindered, and carbon monoxide (CO) is oxidized to carbon dioxide (CO2), and mixing said combustion products with additional air to provide a heated air stream suitable for heating enclosed spaces or construction sites comprising the following steps: (a) delivering a fuel stream into a burner assembly and toward a combustion chamber, said combustion chamber having a length, an inlet and an outlet being located at distal ends of the length of the combustion chamber, the inlet being proximate to said burner assembly, and the outlet being proximate to a heat exchanger, wherein a flow path is provided from the inlet, extending along the length of the combustion chamber, to the outlet; (b) delivering a combustion air stream by a fan assembly into said burner assembly and toward the inlet of said combustion chamber, said combustion air stream being separate from said fuel stream; (c) mixing said fuel and air streams from said burner assembly to form a mixture of streams and igniting the mixture of streams within said combustion chamber, proximate to the inlet and distal to the outlet, wherein the mixture of streams is combusted at a temperature above 1200K in order to (i) form combustion products in which no unburned hydrocarbons remain, (ii) oxidize CO in the combustion products to CO2, and (iii) force conversion of NO2 in the combustion products to NO, and wherein the combustion products move along the flow path until exiting the outlet of said combustion chamber and entering said heat exchanger, wherein the combustion products are cooled to below 1000K to hinder NO from converting to NO2 before exiting said heat exchanger; (d) providing tempering air to the external side of said combustion chamber and said heat exchanger to transfer heat away from the combustion products to the tempering air, forming partially heated tempering air, so that the combustion products are cooled to below 1000 K before exiting said heat exchanger; (e) combining the partially heated tempering air and cooled combustion products after the cooled combustion products exit said heat exchanger; and (f) discharging the combined partially heated tempering air and cooled combustion products into a space to be heated.