CN103868058A - Ultrasonic combustion technology - Google Patents

Abstract

The invention relates to a combustion technology, and especially relates to an ultrasonic combustion technology widely applied to various boiler combustors. The ultrasonic combustion technology employs an ultrasonic combustion idea, and a mixture of combustible matters is accelerated to an ultrasonic state, is blown to a hearth and is combusted in an expansion-insufficient state, thus a large torch, high smoke temperature, low smoke loss and strong convection are obtained, the boiler heat absorption rate is substantially improved, fuel consumption is substantially reduced, energy is saved and environment is protected.

Description

Ultrasonic combustion technology

Technical field

The present invention relates to the combustion technology in a kind of boiler combustion equipment, particularly widely used ultrasonic combustion technology on medium small boiler and CFBB.

Background technology

Conventional boiler burner, its combustion system is deflagration burning.Be characterized in that fuel and air are by slow and passive mode, and complete combustion process with normal pressure pressure chemical combination, various fuel combustions have feature and characteristic separately, but its common ground is: 1, chamber pressure is normal pressure; 2, combustion flame density is identical; 3, smoke density is identical, is about 0.2kg/m ³; 4, the flame temperature reduced levels that exists together; 5, flame meter pressure approximates zero; 6, flame small volume.

At present, all kinds of burners can be realized complete combustion of fuel substantially, but heated body does not obtain best heat absorption, is even ultralow effect, causes waste of fuel serious, need innovation and development badly.

For the boiler in a use, its gross area that is heated (comprising radiation heating-surface and convection heating surface) immobilizes, want to improve boiler heat absorption rate, reduce fuel consumption, have only in radiation side by following way: 1. improve as far as possible flame radiosity face, make it to match with boiler radiation heat-absorbent surface, improve radiation heat transfer process thermal efficiency; 2. improve as far as possible flame temperature, flame temperature can significantly improve temperature and pressure after improving, and significantly increases diabatic potential; 3. improve Fire Radiation gesture, improve the acting ability of flame; 4. reduce dynamic exhaust smoke level, reduce heat loss due to exhaust gas.

Ultrasonic combustion technology, can effectively realize above-mentioned functions.

Summary of the invention

The modal burning of nature is deflagration burning, and deflagration burning not only can spontaneously form, and can be produced immediately by mankind's activity, is easy to realize.Deflagration flame is propagated to burning mixt not with relatively low speed conventionally, and most of hydrocarbon fuel flame propagation velocities are about tens centimeters per second to tens metre per second (m/s)s, and deflagration burning increases the specific volume of fluid, and pressure slightly declines, and is close to identical with environmental pressure.

Deflagration burning has lower combustion intensity and extremely low radiation intensity, main manifestations is: 1. fume side pressure is identical with environmental pressure, be about 0.1MPa, an i.e. atmospheric pressure, 2. flame (flue gas) density is about 1/5 of stove outer air, be that smoke density has reduced by 80%, this has just weakened the radianting capacity of flue gas far away.Meanwhile, 3. torch is shorter, disperses, and does not concentrate, and most of fuel does not burn, and flame particles momentum is little, and displacement is short, causes effective radiation space less; 4. flow of flue gas, take longitudinal laminar flow as main, is typical one dimensional flow, arranges siege for horizontal direction, and mid portion can not get the intense radiation of flame, has seriously reduced boiler heat absorption rate, causes and heats up slowly, and waste of fuel is large; 5. with the perpendicular plane of flow of flue gas direction on without any momentum component.

Currently just mostly belong to this kind of combustion system at widely used boiler combustion device, have a strong impact on boiler heat absorption rate, in the urgent need to innovation and development.

The specific embodiment

Always mobile in the fluid that is subject to it self impact (disturbance) with the object of subsonic speed motion, object always influences each other with fluid particles, disturbance mutually, and it is non-permanent that fluid track belongs to; And with the mobile particle flux of supersonic speed state, be distributed in its peripheral particle static or that move with subsonic speed in relative static conditions, do not form each other disturbance, that is extraneous little pressure disturbance is difficult to change in moment the flow trace of supersonic speed particle flux.The outstanding features such as therefore, it is strong that supersonic speed fluid has rigidity, and rheological coefficient is little, and antijamming capability is strong.

Air has desirable dynamics, very easily realizes Supersonic Flow.

Air accelerate in flow process with combustible as: after fuel oil, combustible gas, coal dust and other fuel etc. mix, continue expansion and accelerate to supersonic speed.

By the burner of supersonic speed art designs, fuel and help combustion gas mixing after spray into burner hearth with the speed of Mach number 1.0≤Ma≤2, gaseous mixture reduces pressure, expands, burns.

The benefit of doing is like this:

1, flame torch is large

Adopt the burning of supersonic speed technical organization, because the supersonic gas energy of flow is large, inertia is strong, and streamline is long, very easily forms large torch.Flame is torch, after prolongation, obtains desired expansion, longitudinally extends, and can cover whole boiler dead angle, is particularly suitable for CFBB and heats up.

2, flame temperature significantly improves

According to radiation heat absorption equation: $Q_v=\frac{\mathrm{\σ}\×\mathrm{\α}\×H}{B}({T^4}_{\mathrm{hy}}-{T^4}_b)$

Q _vrepresent radiation intensity, T ⁴ _hyrepresent flame temperature, T ⁴ _brepresent boiler water wall initial temperature.Boiler heat absorption capacity is directly proportional to the biquadratic of flame temperature! Visible, improve flame temperature and can significantly improve boiler heat absorption rate.

The flame temperature that traditional combustion mode obtains is generally 1100 ℃ of left and right or lower, and the burner of employing ultrasonic combustion technology, flame is real core, entire body is bright, can reach 1600-1800 ℃.

3, the flue gas moment of momentum significantly improves

Adopt the burning of supersonic speed technical organization, flame is except having longitudinal momentum, also there is radial momentum component, the flue gas of High Rotation Speed, high strength is washed away (shearing) boiler wall, and its heat-sink shell thermal resistance is significantly reduced, effectively reduce boundary layer thickness, increase substantially heat transfer intensity, improved thermotransport process, the inner flow of flue gas aerodynamic field of burner hearth is strengthened.

4, gas radiation is pressed significantly and is improved

Adopt the burning of supersonic speed technical organization, after fuel ejection, in owing swelling state, continue expansion and expand, until with around smoke behavior is identical, flame becomes the process of flue gas, develop into Fire Radiation and press the process of transmitting.

5, flame volume density significantly increases

Adopt the burning of supersonic speed technical organization, after fuel combination ejection, keep high density, after burning, form high temperature high compact core radiant body, this has just improved the radiation amounts of particles in flame unit volume, the rigidity flame that the loose type flame of changing deflagration burning is solid type, significantly improve flame radiation diabatic potential, also just receive highdensity radiation corresponding to inboard wall of burner hearth heat absorption place.

6, reduced exhaust gas heat loss

Adopt the burning of supersonic speed technical organization, whole combustion process is oxygen deprivation state, and air consumption is few, thereby has just reduced dynamic exhaust smoke level, has then just reduced total exhaust smoke level, has also just reduced heat loss due to exhaust gas.

7, fuel combustion speed is significantly accelerated, and significantly suppresses the generation of nitrogen oxide.

Claims (7)

1. ultrasonic combustion technology, is characterized in that combustion air and fuel form to accelerate gradually to become the supersonic speed mixed airflow of owing swelling state after flammable mixture and enter hearth combustion.

2. ultrasonic combustion technology according to claim 1, it is characterized in that combustion air can a part enter burner hearth participation burning with supersonic speed state, another part enters hearth combustion with subsonic speed state, also can all enter hearth combustion with supersonic speed state.

3. ultrasonic combustion technology according to claim 1, is characterized in that fuel form can be gas, liquid, powder or their mixture.

4. ultrasonic combustion technology according to claim 1, is characterized in that supersonic speed mixed airflow owes swelling state, can be also optimum expansion state.

5. ultrasonic combustion technology according to claim 1, is characterized in that supersonic speed mixed airflow, and its flowing velocity is greater than local velocity of sound, but also can equal local velocity of sound or claim critical speed.

6. ultrasonic combustion technology according to claim 1, is characterized in that the fuel of flammable mixture and air are outer mixed.

7. ultrasonic combustion technology according to claim 6, is characterized in that flammable mixture mixing ratio can be 1: 1, can not be also.