Burners

Abstract

The invention provides a nozzle-mixed burner for use in an endothermic process such as hydrogen reforming or ammonia reforming or ethylene cracking or EDC cracking. The burner comprises a fuel duct extending axially through a wall of the furnace. The fuel duct delivers gaseous fuel to an array of nozzles extending laterally to spray the fuel outwardly into an annular chamber defined by a cap. Combustion air is delivered to the chamber by way of a primary air duct. A convergent-divergent section of the duct and an outwardly divergent section of the chamber together form a radially extending venturi. Combustion of the fuel, supplemented by the venturi effect, draws the air through the duct by natural inspiration.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority from United Kingdom Patent Application No. 10 14 969.8, filed Sep. 9, 2010 the entire disclosure of which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention relates to burners, particularly but not necessarily burners for use in radiant-wall side-fired furnaces of the kind used in endothermic processes such as hydrogen reforming, ammonia reforming, ethylene cracking and ethylene dichloride (EDC) cracking.[0004]2. Description of the Related Art[0005]Considering hydrogen reforming as an example, this is an industrial process for the production of hydrogen by reacting hydrocarbons such as natural gas with steam in the presence of a catalyst. In the primary reaction, methane reacts with water to yield carbon monoxide plus hydrogen:CH4+H2O→CO+3H2  [Equation 1][0006]The reaction is highly endothermic, and therefore the process is car...

AI Technical Summary

Benefits of technology

[0013]It is a primary object of the present invention to enable a furnace to operate with a range of fuel gases wider than hitherto, including particularly gases with a higher concentration of hydrogen than hitherto. At the same time the invention facilitates operation without forced draught while meeting permitted noise levels and substantially avoiding a risk of flashback.

Problems solved by technology

Fuels with relatively high flame speeds, such as those containing relatively high proportions of hydrogen which are now increasingly used, may cause a flashback.

At a minimum, this reduces the performance of the plant; and if it results in damage to the burner, the cost of repair or replacement is considerable, especially if the plant has to be shut down.

With hundreds of burners in a typical furnace, the risk of flashback in at least one is high.

Hundreds of burners create a great deal of noise, from the combustion itself and from the delivery of combustion air, and the fact that the venturi tubes of the conventional burners provide hundreds of essentially straight passages through the wall of the furnace exacerbates the impact of this noise on the environment of the plant.

Generally, permitted noise levels are limited by environmental controls and / or health and safety regulations.

However, in conventional burners this constrains the flow of combustion air, so the risk of flashback is increased.

However this increases both capital cost and running cost, and also introduces another source of noise outside the furnace.

Images