초록 ▼

A method of reducing NO.sub.x determines an NO.sub.x concentration profile within a zone of the furnace which is at a temperature below 2600.degree. F. A stream of fluid fuel is injected into at least one region of relatively high NO.sub.x concentration so that the fluid fuel mixes therein with the

A method of reducing NO.sub.x determines an NO.sub.x concentration profile within a zone of the furnace which is at a temperature below 2600.degree. F. A stream of fluid fuel is injected into at least one region of relatively high NO.sub.x concentration so that the fluid fuel mixes therein with the flue gas. The fluid fuel is natural gas, hydrogen, C.sub.x H.sub.y compounds, C.sub.x H.sub.y O.sub.z compounds or mixtures primarily of those compounds, in sufficient quantity to promote a reaction between nitrogen oxide in the flue gas and the fluid fuel, so as to substantially reduce nitrogen oxide content of the flue gas. The injector through which the fluid fuel is injected can be moveable and may have valves or deflectors to aid in directing the fluid fuel to regions of relatively high NO.sub.x concentration.

대표청구항 ▼

[ We claim:] [1.] An improved apparatus for reducing nitrogen oxide in flue gas in a furnace wherein a fuel is burned in a primary combustion zone and produces a flue gas containing nitrogen oxide that passes through a zone in which the flue gas has a known concentration profile wherein there are at

[ We claim:] [1.] An improved apparatus for reducing nitrogen oxide in flue gas in a furnace wherein a fuel is burned in a primary combustion zone and produces a flue gas containing nitrogen oxide that passes through a zone in which the flue gas has a known concentration profile wherein there are at least two regions, at least one region of higher NO.sub.x concentration and at least one region of lower NO.sub.x concentration wherein the improvement comprises at least one injector attached to the furnace and positioned for injecting a secondary combustible fuel along an axis which intersects a wall of the furnace at an angle and into the at least one region of higher NO.sub.x concentration and also comprises a motor connected to the at least one injector for changing the angle at which said axis intersects the furnace wall. [21.] An in-furnace method of reducing nitrogen oxides in flue gas comprising the step of:a. selecting a zone in the furnace through which the flue gas passes at a temperature not greater than 2600.degree. F.;b. determining an NO.sub.x concentration profile within the zone wherein said profile reveals at least one region of higher NO.sub.x concentration and at least one region of lower NO.sub.x concentration;c. injecting a stream of fluid fuel into the at least one region of higher NO.sub.x concentration so that the fluid fuel mixes therein with the flue gas, said fluid fuel being selected from the group of fluids consisting of natural gas, hydrogen, C.sub.x H.sub.y compounds, C.sub.x H.sub.y O.sub.z compounds and mixtures primarily of said C.sub.x H.sub.y compounds and said C.sub.x H.sub.y O.sub.z compounds, in sufficient quantity to promote a reaction between said nitrogen oxide in the flue gas and said fluid fuel, so as to substantially reduce the nitrogen oxide content of the flue gas.