Low NOx staged fuel injection burner for creating plug flow

Abstract

A burner for producing a plug-like flow and low NOx emissions. The burner has a central air jet and plural staged fuel jets surrounding the central jet. The ratio of the sum of the momentums of vector components of the staged jets along respective axes parallel to the central longitudinal axis of the central jet to the momentum of the central jet along that axis is within the range of 0.5 to 1.5 and most preferably 0.8.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to burners for furnaces, and in particular to staged burners for creating a plug-type flow pattern with low nitrogen oxides (NOx) emissions.[0002]Furnaces for ethylene cracking and other industrial processes, e.g., steam-methane reformers, typically make use of burners utilizing fuels such as natural gas, propane, hydrogen, refinery off-gas and other fuel gas combinations of various calorific values. For example, steam-methane reformer furnaces are used to produce hydrogen and carbon monoxide by reforming a hydrocarbon feed with steam and, at times, carbon dioxide at high temperatures. The furnace used for steam-methane reforming can be configured in several different structures. One of the most conventionally used arrangements for such reformer furnaces has vertical reformer tubes arranged in rows. The burners of the furnace can be located on the furnace's floor, its ceiling or its walls. As is known, operating a reform...

AI Technical Summary

Benefits of technology

[0005]The subject invention constitutes a staged fuel burner for establishing a plug-like flow, and is particularly useful in furnaces, such as ethylene crackers, reformers, etc. The staged burner comprises a central nozzle and plural staged nozzles. The central nozzle has an orifice producing a jet of air directed along a central longitudinal axis. The staged nozzles surround the central nozzle and each has at least one orifice producing a s

Problems solved by technology

As is known, operating a reformer tube above the desired temperature can cause large decreases in tube life.

This, in turn will adversely affect the economics of the plant since the tubes are a substantial portion of the overall cost of the plant and require large expenditures of time and effort to replace one that has failed.

Tube hot spots can arise from undesirable furnace flow patterns which cause flame impingement.

NOx emissions have been identified as contributing to the degradation of environment, particularly degradation of air quality, formation of smog and acid rain.

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