초록 ▼

A combustion process for nitrogen- or for sulphur- and nitrogen-bearing fuels wherein fuel combustion is divided, by staged oxygen (preferably in the form of air) injection, into at least two combustion zones. The first combustion zone involves providing fuel-rich stoichiometric conditions under whi

A combustion process for nitrogen- or for sulphur- and nitrogen-bearing fuels wherein fuel combustion is divided, by staged oxygen (preferably in the form of air) injection, into at least two combustion zones. The first combustion zone involves providing fuel-rich stoichiometric conditions under which nitrogen chemically bound in the fuel (i.e. fuel-bound nitrogen) is substantially converted to molecular nitrogen. The second (final) combustion zone comprises at least two stages. In the first stage of the final combustion zone, combustion products from the first combustion zone are further combusted under a condition of fuel-rich stoichiometry, preferably at an oxygen/fuel stoichiometric ratio of from about 0.80 to about 1.0 and at a temperature of less than about 2200 K. In the second stage of the final combustion zone, combustion products from the first stage are combusted at an oxygen/fuel stoichiometric ratio of greater than about 1.0 and at a temperature of less than about 1500 K. In this final zone, fuel combustion is completed while formation of new thermal NOx is substantially prevented. Thus, the process may be used to reduce emissions of undesirable nitrogenous compounds (e.g. NOx) which would ordinarily be formed during completion of fuel combustion. The process is particularly appropriate for use with the fuel-rich gases from a burner designed to control air pollutants arising from sulphur and nitrogen in the fuel.

대표청구항 ▼

A combustion process for a nitrogen-bearing fuel comprising the steps of: (a) introducing said fuel into a first combustion zone; (b) combusting said fuel in said first combustion zone under a condition of fuel-rich stoichiometry at an oxygen to fuel stoichiometric ratio of from 0.45 to 0.80 and at

A combustion process for a nitrogen-bearing fuel comprising the steps of: (a) introducing said fuel into a first combustion zone; (b) combusting said fuel in said first combustion zone under a condition of fuel-rich stoichiometry at an oxygen to fuel stoichiometric ratio of from 0.45 to 0.80 and at a temperature in the range of from 1500 K to 1800 K whereby fuel-rich combustion products are produced and undesirable nitrogenous compounds are reduced to low levels; (c) passing said fuel-rich combustion products into a two-stage final combustion zone; (d) combusting said fuel-rich combustion products in the first stage of said final combustion zone under a condition of fuel-rich stoichiometry at an oxygen to fuel stoichiometric ratio of from 0.80 to 1.0 and at a temperature in the range of from 1500 K to 2200 K to produce combustion products having nitrogenous oxide levels reduced substantially to near zero while substantially burning out combustibles virtually free from generation of any additional thermal nitrogenous oxides; and (e) thereafter, combusting said combustion products in the second stage of said final combustion zone at an oxygen to fuel stoichiometric ratio of greater than 1.0 and at a temperature of less than 1500 K to facilitate substantially complete fuel burnout in the second stage of said final combustion zone.