The way to reduce emissions of harmful substances in combustion

 

(57) Abstract:

Can be used when burning coal, oil and other fuels. Prepare the fuel dispersed system consisting of fuel, liquid and solid additives by dispersing and mixing the components, serves a cooked-system into the combustion chamber, and cooking fuel dispersion of the system is performed in two stages, first preparing a suspension of solid additives in liquid insertion tool or in the fuel, and then in the slurry, additives or suspension of fuel and additives enter the remaining components of the fuel dispersed system, is dispersed, the particle diameter of the suspension does not exceed 25 μm, and the diameter of the particles of solid additives in suspension does not exceed 20 μm. Improves the efficiency of the use of additives.

The invention relates to the field of power engineering, in particular to the burning of coal, oil, and other fuels in the furnaces of the boilers of thermal power plants, heating plants, etc.

Known methods of burning fuel, reducing pollution of the exhaust gases at the outlet from burning plants by treating exhaust gases of chemical and physico-chemical methods, which require large capitaline concentration of harmful substances by burning fuel directly in the combustion chamber by the use of additional substances, added to the fuel or furnace [2, 3].

In the method [2] to remove sulfur and nitrogen oxides from flue gases produced by burning coal, oil and other fuels in the combustion gases blown into finely ground particles of magnesium oxide in an excessive amount relative to the amount required for complete binding of harmful substances, in the presence of water.

The known method [3] reduction of emissions of harmful substances during combustion is based on the injection of additives in the form of an aqueous suspension directly into the combustion chamber.

These methods allow to reduce the concentration of nitrogen and sulfur oxides in flue gases in 2-2,5 times. However, in these methods, additives contribute directly into the combustion chamber, while the additives are distributed in the chamber relative to the fuel and oxidant unevenly, i.e., the relative concentrations of water and additives to the concentration of the fuel and oxidant are heterogeneous and depend on the space coordinates in the combustion chamber. Therefore, the suppression of the harmful components of exhaust gases and their absorption occurs inefficiently.

Known methods of reducing emissions, providing pre-treatment tank is uniform distribution in space of the furnace all components and more complete linking, the suppression and destruction of harmful emissions contained in the flue gas, which is a product of combustion.

The closest to the invention by the combination of essential features is a way to increase the efficiency of fuel combustion with reduced formation of nitrogen oxides and sulfur in the exhaust gas by the fuel dispersed systems consisting of fuel additives in the form of sulfur absorber and inhibitor and supply of prepared fuel dispersed system in the combustion chamber [6] . In the known method also achieves a uniform distribution of the components of the fuel in the combustion chamber, however, the known method does not provide the conditions to ensure the homogeneity of the components dispersed in the fuel system at the time of its preparation, which reduces the efficiency of the added fuel substances.

The problem to which the invention is directed, is more complete binding of harmful substances generated in the combustion process.

This problem is solved by making the fuel dispersed system with improved distribution of the additives, which leads to a more efficient use of the latter.

At plants burning fuel, including cooking fuel dispersed system consisting of fuel, liquid and solid additives by dispersion and mixing of the components and the supply of prepared fuel dispersed system in the combustion chamber, the cooking fuel of the dispersed system is performed in two stages, first prepare a suspension of solid additives in liquid insertion tool or in the fuel, and then in the slurry, additives or suspension of fuel and additives enter the remaining components of the fuel dispersed systems and dispersed, while the diameter of the particle suspension additives in the fuel does not exceed 25 μm, and the diameter of the particles of solid additives in suspension does not exceed 20 microns.

Get fuel complex dispersed system, which consists of fuel, inside of which are uniformly distributed droplets of a suspension of solid additives in liquid insertion tool or a drop of the suspension with solid fuel additive, which are uniformly distributed droplets of liquid additive. Fuel disperse system in the form of drops, including drops of suspension into a high-temperature zone of the combustion chamber, vzryvoobrazno breaks down into even smaller droplets under the action of the vapour pressure of liquid additive (boiling water) suspension, which is when preparation of suspension fuel and solid additives and subsequent dispersion liquid additive (water) receive fuel dispersed system, in which drops of liquid additive (water) are in suspension or mixture of additives and fuel. Spraying droplets of fuel dispersed system in the combustion chamber and then additional atomization with an explosive boiling of water leads to effective interaction with pollutant substances and reduction of emissions in the exhaust gases of harmful products of incomplete combustion, oxides of nitrogen and sulfur. As solid additives can be used CaCO2, MgO, Ca(OH)2etc. as liquid additives you can use the water.

Conducted by the applicant's analysis of the level of technology has allowed to establish that the applicant is not detected similar, characterized by signs, identical to all the essential features of the claimed invention, therefore, the claimed invention is new.

Analysis of the known from the prior art solutions regarding distinctive features of the claimed invention showed that the claimed solution is not necessary for the expert in the obvious way from the prior art, i.e., meets the requirement of inventive step.

Provided by the invention technical result compared with the prototype is as follows.

Decreases the maximum (peak) temperature in the combustion, reduces the temperature gradient of the temperature field becomes more uniform, which reduces the formation of harmful compounds oxides of nitrogen and products of incomplete combustion of fuel.

Increases the intensity of the combustion of small droplets of fuel dispersed system additionally sprayed with water vapor, which, besides reducing the coefficients of chemical and mechanical underburning, i.e. the reduction of fuel consumption and emissions of soot, cause a decrease in the length of the flame stabilization of combustion of the flame, which leads to the possibility of reducing the length and the unit volume of the combustion of fuel and capital costs.

Combustion use fuel dispersed system with the following components: fuels - liquid structuresa solid additive - powdered magnesium oxide. In addition, in the combustion chamber serves the oxidant is oxygen. In the first stage, powdered magnesium oxide to the size of the particles is not more than 20 μm, taken in an excessive amount relative to the stoichiometric 1.5-1.8 times, which is enough to link contained in the fuel sulfur is mixed with water, taken in an amount of 30%. The resulting suspension of solid additives in the water and the fuel oil dispersant. In the case of suspension of fuel and additives on the first stage of powdered magnesium oxide with a particle size of not more than 20 μm, taken in an amount in accordance with the above, mixed with fuel, and then the resulting slurry and water is fed into the disperser. In the dispersant continuous action, if necessary, with the recirculation line, get the fuel dispersed system in which the dispersed phase is a suspension of the additive in the water is evenly distributed in the form of fine particles down to 25 microns in the fuel. Fuel combustion is relative homogeneous distribution of all supplied components. A drop of oil with drops of suspension additives in the water vzryvoobrazno broken down into even smaller droplets of fuel burning in less time that obespechivayushchaya and the reduction of harmful emissions into the atmosphere. During the tests, the mode of distribution of particles in suspension in the oil has been changed from 7 μm to 15 μm, depending on the mode of operation of the dispersant and water content. Adding water was taken into account the water in the flooded fuel.

Thus, a preliminary dispersion of the additive with water or fuel can be evenly sprayed in the combustion chamber not only fuel, but also evenly to introduce additives, which increases the efficiency of binding of harmful components and reduce their education.

Sources of information

1. Rusanov, A. A., Urbach, I. I., Anastasiadis A. P. Purification of waste gases in industrial engineering. Meters, Energy, 1969.

2. Patent Germany N 3410731, class B 01 D 53/34, 1985.

3. Patent Germany N 3444469, class C 01 L 10/00, 1986.

4. Patent Germany N 3409014, class C 01 L 10/00, 1985.

5. Patent Germany N 3325570, class C 01 L 10/00, 1985.

6. The application RU N 94003846/26, class B 01 D 53/60, 1995.

The way to reduce emissions of harmful substances in combustion, comprising preparing the fuel dispersed system consisting of fuel, liquid and solid additives by dispersion and mixing of the components and the supply of prepared fuel dispersed system in Cham shall prepare a suspension of solid additives in liquid insertion tool or fuel, and then in the slurry, additives or suspension of fuel and additives enter the remaining components of the fuel dispersed system, is dispersed, the diameter of the particles of suspension does not exceed 25 μm, and the diameter of the particles of solid additives in suspension does not exceed 20 μm.

 

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