RU2228490C2 - Process of fuel combustion - Google Patents

Abstract

FIELD: fuel burning under oscillatory condition. SUBSTANCE: process of fuel combustion consists in its supply to burning aid with subsequent mixing with air and combustion. Air leaks through electromechanical generator with rotating flappers overlapping air flow conduit by 3-97% with rotational speed of motor between 1000- 1600 rpm and oscillation frequency of air flow from 30 to 600 Hz prior to supply for mixing with fuel. EFFECT: reduced vibration of equipment, enhanced stability of burning and diminished cost of fuel for burning. 5 dwg

Description

The invention relates to the field of preparation and combustion of fuel (gas, fuel oil, etc.) in a gas-dynamic mode and can be used for, etc.

The most famous and used types of fuel combustion in gas-dynamic mode include vibrational and vibrational combustion.

During the 50-60s of the 20th century, devices were created that implement vibrational combustion by applying ultrasonic vibrations to the flow of a fuel-air mixture [1] and others. The nature of the effect of these vibrations on the process of mixing and burning of fuel is to increase the flow turbulization. When burning in an ultrasonic field, an increase in the temperature of the open flame in its separate areas by 200-300 ° C [2] and an increase in heat transfer from the flame to the wall by 10-30% are observed.

The disadvantage of resonant systems of vibrational combustion is the complex organization of a stable vibrational regime.

At present, in Russia and abroad, a large number of devices have been developed that implement vibrational combustion, with which solid, liquid, and gaseous fuels are burned. The main physical method by which the indicated combustion is realized is intermittent (oscillatory) air supply to the combustion chamber [3], pulsed fuel supply to the chamber due to special nozzle devices [4] and intermittent air supply.

The use of the positive aspects of vibrational and vibrational combustion is relevant, but the practical use of these devices remains insufficient, which is associated with poor knowledge of vibrational processes and insufficient experimental testing of devices [5].

A known method of burning fuel [6], according to which fuel oil is fed through resonant pipes, reactors, a gasifier and a fuel nozzle to a block of vibration combustion chambers equipped with an acoustic resonator in which it is mixed with air and burned. About 8% of the air enters the chamber through the gasifier, and the rest through the duct. The pressure oscillation in the chamber reactors acts on each other through the waveguide. This ensures the connectedness of the cameras as acoustic systems.

Using this method showed that from vibrations there is a series of destruction in the design of the cameras themselves, therefore, further structural improvements are required.

There is another method of burning fuel [7], which we adopted as a prototype. According to this method, air that is mixed with fuel is supplied to the fuel leaving the burner by means of two nozzles connected to a jet oscillation gas generator. Alternating outflow of air from the nozzles acts on the torch from opposite directions, forcing it to vibrations transverse to its axis. As a result of this, the torch acquires a stable turbulent structure, and the process of oxidation of fuel particles occurs more intensively and fully, which reduces the chemical incompleteness of fuel combustion.

The disadvantage of the proposed method is a significant increase in noise, an increase in pressure fluctuations inside the combustion chamber and equipment vibration.

The objective of the proposed technical solution is to increase the efficiency of the fuel combustion process - reducing noise, pressure fluctuations inside the combustion chamber, equipment vibration and creating sustainable vibrational combustion.

This is achieved due to the fact that in the method of burning fuel, which consists in feeding it to a burner device, followed by mixing with air and burning, the air is passed through an electromechanical air generator (EMVG) with rotating shutters partially covering the air channel before being mixed with fuel flow with a frequency of rotation of the electric motor at a speed of electric motor (ChOE) of 1000-6000 per minute. The degree of overlap of the air supply channel (SPKPV) by rotating EMVG flaps varies in the range of 3-97%, and the frequency of fluctuations of the air flow (CHKVP) is within 30-600 Hz.

The degree of activation of the air flow (SAWP) depends on SPKPV shutters computer [8]. With low SPKPV - less than 20% SAVP is significantly reduced. With an increase in SPKPV above 80%, the SAWP increases, but the performance of the EMVG installation noticeably decreases.

Choi EMVG rotary shutter is equal to 1000-6000 per minute. A decrease in PEC below 1000 per minute lowers the SAVP, and an increase in PEC more than 6000 per minute is theoretically and practically possible, but not economically feasible, since it increases the cost of EMVG design.

ChKVP lies in the range of 30-600 Hz and is regulated by the ChoE and the number of rotating shutters EMVG. Maximum efficiency (regardless of the type of fuel burned) is achieved when EMVG is operated with a ChOE of 3000 per minute, at which an oscillatory air supply to the burner device with a ChKVP of 100-200 Hz is realized.

In the process of EMVG operation, gas fluctuations in a rotating electromagnetic field (compression, rarefaction of gas, etc.) can occur. Therefore, heating of the gas and activation of its components (oxygen, nitrogen, carbon dioxide, water, etc.), as well as the formation of hydrogen peroxide from water vapor, can occur, but $\genfrac{}{}{0ex}{}{\text{.}}{\text{2}}$ and ^. OH radicals. As a result of this, the reactivity of air components can increase significantly.

The essence of the proposed method is illustrated by examples.

Example 1. The functional diagram of the installation for the production of black crushed stone and asphalt concrete using EMVG at the plant of the Yekaterinburg road construction department "Sverdlovsavtodor", the village of Beloyarsky, is shown in Fig.1.

In this scheme, fuel oil from tank 8 is pumped through fuel line 6 to burner 2, where it is mixed with air supplied by fan 5 through EMVG 4 through duct 3, with an air flow channel overlap of 3-97% and an electric motor speed of 3000 per minute , and burned. In the drying and mixing drum 1 with the help of a burner 2, drying of crushed stone, mixing, heating and preparation of the asphalt concrete mixture is provided.

The results of industrial tests are shown in table 1, from which it follows that the use of EMVG allows to reduce the specific consumption of fuel oil by 9.3% in the preparation of asphalt concrete.

Example 2. Industrial tests were carried out on a steam gas boiler E-1.0-0.9G-3 in the boiler room of the state production association "TEKOM", Yekaterinburg. The installation diagram is shown in figure 2.

According to this scheme, the fan 5 through the gate 9 and EMVG 4 through the duct 3 supplies air to the burner 2, where it is mixed with fuel oil and burned. Combustion fuel is used to heat the steam boiler 10.

The test results are summarized in table 2. As can be seen from the table, with an increase in the speed of EMWG rotation from 2000 to 6000 rpm, the specific gas consumption for generating 1 Gcal of thermal energy decreases by 1.43-7.27%.

Example 3. Industrial tests were carried out in the technological cycle of the cupola furnace of the Nizhny Tagil boiler-radiator plant. As "EMVG, a device was used to intensify the combustion of solid fuels in combustion systems with layer-by-layer burning [9] (Pat. No. 2149311, 7 F 23 V 1/16). The installation diagram is shown in Fig.3.

In this scheme, the air of the ventilation unit 5 is first supplied to the recuperator 11, in which it is heated to the required temperature and then fed through the air duct 3 to the tuyeres 13 with EMVG 4 installed in them, where it is activated and fed into the cupola furnace under a layer of coke for burning it. (In figure 3: 9 - gates, 12 - air ring, 14 - metal notch, 15 - slag notch).

The test results are presented in table 3.

An analysis of the data in the table shows that during the operation of EMHG, the melt temperature is increased by an average of 30–40 ° С from the initial temperature (maximum by 70–75 ° С due to a decrease in melt viscosity). The furnace productivity increases by 10%, and at the same time, the specific fuel consumption decreases by one ton of cast iron and one ton of finished products (by 5-10%).

Example 4. Industrial tests were conducted to incorporate EMVG into the technological cycle of mineral wool production. As the EMVG, the device shown in Example 3 was used. According to the diagram of FIG. 4, air is supplied by the fan 5 through the duct 3 through the gate 9 first to the EMVG 4 and then to the cupola furnace 16. The test results are shown in table 4.

From the table it follows that during the operation of EMVG in the production line, the temperature in the furnace and the temperature of the outgoing melt increase by 80-100 ° C. There is an increase in the temperature of the exhaust gases above the slag layer, Fig.5. Figure 5 shows the dependence of temperature changes, ° C, exhaust gases above the slag layer during cupola operation, on the start time of the slag loading, min .: I with EMVG; II without EMVG; the appearance of the torch: I at 410 ° C, II at 400 ° C. (The frequency of rotation of the EMVG engine is 3000 rpm, the oscillation frequency of the air flow is 100-300 Hz.)

Thus, the appearance of the torch takes place at 410 ° C (with EMVG) and at 400 ° C (without EMVG). When starting EMVG, the pressure in tuyeres (at the air outlet to the furnace) increases by 30%, which indicates an increase in the linear component of the air velocity and, accordingly, its kinetic energy.

When using EMVG, table 4, the productivity of the processing line is increased by 10% and specific fuel consumption is reduced by 10%.

 Comparison of the proposed method with the prototype [7] shows an increase in the efficiency of fuel combustion. Since air preparation before mixing with fuel takes place in a separate apparatus (EMVG), noise and pressure fluctuations inside the combustion chamber are not observed. The work of EMVG according to the proposed method, in comparison with the prototype [7], is characterized by stability, which eliminates equipment vibration and instability of fuel combustion. In addition, the proposed method, in contrast to the prototype [7], allows to reduce fuel consumption for combustion and to increase the temperature of the process without changing the technological modes of fuel combustion.

Literature

1. A.S. 257665 USSR, class 24. Vibration firebox. BI. 10/12/1970.

2. Kuban P.N. To the question of the influence of ultrasound on the combustion process / Thermal Engineering. 1962. No. 1.

3. A.S. 228217 USSR, class 24 century A device for pulsating combustion. BI. 05/23/1969.

4. Gilod V.Ya. Thermotechnical characteristics of fuel. The use of gas and fuel oil in industry / Modern methods of burning liquid fuel. VINITI. M., 1965, 1967.

5. Podymov V.N., Severyanin V.S., Schelokov Y.M. / Applied research of vibrational combustion. Kazan. Kazan University. 1987.

6. Babkin Yu.L., Shilin A.N. The block of chambers of pulsating combustion of fuel oil BKPK-5000. Pulsation burning. Chelyabinsk: Proceedings of the NTO EP. 1968.

7. A.S. 249534 USSR, class 241.5. The method of burning liquid and pulverized fuel. BI. 12/26/1969.

8. Pat. RF № 2131557, MKI 6 F 23 R 3/04.

9. Pat. RF № 2149311, MKI 7 F 23 B 1/16.

Claims (1)

A method of burning fuel, which consists in feeding it to a burner device, followed by mixing with air and burning, characterized in that the air is passed through an electromechanical generator with rotary dampers, covering 3-97% of the air flow channel at a speed an electric motor of 1000-6000 rpm and an oscillation frequency of the air flow of 30-600 Hz.

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