DE2944153C2 - Method of reducing NO? X? - and / or SO ↓ 2 ↓ emissions during the combustion of fuels - Google Patents

Description

When burning conventional fuels z. B. in power plants, households and internal combustion engines of all kinds, etc., in addition to water and carbon dioxide, larger or smaller amounts of environmentally harmful substances are produced depending on the type of combustion and the fuel used; when burning in power plants z. B. significant amounts of NO and SO ₂ , in the combustion in car engines and in households, which is generally carried out at lower temperatures (<800 ° C), in addition to NO ₁ and / or SO ₂ , CO is also used in larger amounts emitted.

It is known (DE-AS 27 16 973) to degas coal dust before combustion by heating it to over 800 ° C. in order to reduce NO ₁ and SO ₂ emissions during combustion.

In this process, known as rapid degassing, however, a technically complex separation has to be carried out the pollutants removed during the degassing from the inert gas carrying the fuel during the degassing take place.

The present invention is based on the object of developing a simple and effective method for reducing NO and / or SO ₂ emissions during combustion processes, which can also be implemented in existing systems without great expense.

The present invention therefore relates to a method for reducing NO and / or SO ₂ formation and thereby their emission during the combustion of conventional fuels, the fuel being warmed up before it comes into contact with highly oxygenated gases in the combustion chamber and is brought into contact with the highly oxygen-laden gases at the preheating temperature, characterized in that the preheating to 150 to 450 ° C takes place.

In addition to the various petroleum fractions, conventional fuels for the purposes of the invention such as B. gasoline, heating oil or heavy oil also natural gas and various types of coal as well as chemical ones Products such as B. methanol, ethanol, aniline and other organically bound carbon containing Compounds understood, as well as their solutions, mixtures and emulsions with each other and with water, as far as they can be burned.

For the combustion of the fuel prepared by the method according to the invention, everyone can conventional burners, especially those in which the dispersion of the fuel by means of single-component and Two-substance nozzles will be used. When burning low-boiling, liquid fuels is however, it is advantageous to reduce the atomization of the fuel, z. B. by means of swirl nozzles and the combustion under pressure.

In the method according to the invention, when using The atomizing medium (e.g. air) can also be preheated by two-fluid nozzles so that the Fuel is not cooled down again by supplying cold atomizing media before it actually burns will.

With the method according to the invention, the formation of NO and / or SO ₂ and thus their emissions can be greatly reduced, even in existing plants, without great effort. There is also a strong reduction in CO emissions.

The liquid and / or gaseous fuel is preferably preheated in heat exchangers, preferably in an energy-saving manner with the aid of the hot exhaust gases. Solid fuels are preferably preheated in fluidized beds by means of hot exhaust gases
In the process according to the invention, fuels with a higher content of sulfur can advantageously also be used without prior separation of the sulfur compounds being necessary. If necessary, however, after preheating, before the actual combustion, the sulfur can be separated off as H ₂ S under reducing conditions.

The process according to the invention is to be explained in more detail by the following examples.

example 1
(Single fluid nozzle)

In a test incineration plant, 35 mVh natural gas and 14 l / h aniline with 1020 mVh air were used burned. The combustion chamber temperature was approx.

1000 ° C. When aniline was metered in at room temperature (28 ° C), the ΝΟ, concentration in the exhaust gas was about 500 ppm. The temperature of the metered aniline was then increased gradually. When aniline temperature of 100 ° C, 400 ppm NO ,, at 15O ⁰ C for about 320 ppm NO, and ppm at 26O ⁰ C 250 NO measured in the exhaust gas.

Example 2
(Single fluid nozzle)

In the same experimental incineration plant, about 12 l / h of aniline were ^{burned with 1450 m 3} / h of air at combustion chamber temperatures of about 460 ° C. When aniline was metered in at room temperature, the CO concentration in the exhaust gas was about 1400 ppm. After the aniline was preheated and fed in at 160 ° C., the CO concentration was only 350 ppm. The ΝΟ, concentration fell from 220 to 65 ppm.

Example 3
(Two-substance nozzle)

18 liters of aniline were burned per hour together with 1040 m ^{3 of} air and 30 m ^{3 of} natural gas. The combustion chamber temperature was approx. 1000 ° C. The temperature of the combustion air was kept constant at approx. 20 ° C.

In the following information, tempeh only understood the temperature of the atomizing air.

Temp. Aniline

Temp air
NO,

30 ⁰ C 20 ⁰ C 260 ppm

205 ⁰ C 20 ° C 180 ppm

215 ° C 220 ° C 100 ppm

Example 4 (Two-substance nozzle)

26 liters of nitrobenzene were ^{burned per hour with 1030 m 3 of} air and 30 m ^{3 of} natural gas. The temperature measured in the combustion chamber was approx. 1000 ^° C.

Temp.Nilrobcnzol

Temp.uifi
NO,

20 ⁰ C 255 ° C

20 ° C 220 ⁰ C.

550 ppm 250 ppm 4
Example 5

(Two-substance nozzle)

45 liters of heating oil (heating oil S + EL [1:!] With 0.85% by weight of Schwetel) were ^{burned per hour with 1030 m 3 of} air and? .O m ^{3 of} natural gas. The combustion chamber temperature was approx. 1000 ° C.

Temp.oi 14 ° C 235 ° C

Temper. 20 ⁰ C 200 ° C

NO, 100 ppm 40 ppm

SO ₂ 100 ppm 70 ppm

Claims (2)

Patent claims: 1. Process for reducing the NO _x and / or SO ₂ formation during the combustion of conventional fuels, whereby the fuel is warmed up before it comes into contact with gases with a high concentration of oxygen in the combustion chamber and, at the preheating temperature, with the highly oxygenated .igen gases is brought into contact, characterized in that the preheating to 150 to 450 ° C takes place 2. The method according to claim 1, characterized in that the fuel to a temperature above 180 ⁰ C, preferably 200 ° C, particularly preferably above 250 ° C, is heated.