CN111520712A - Ultrasonic atomization combustion system and method suitable for pyrolysis oil - Google Patents

Abstract

The invention discloses an ultrasonic atomization combustion system and method suitable for pyrolysis oil, which belongs to the field related to biomass pyrolysis oil, so as to solve the problem that the combustion of the current pyrolysis oil combustion system is easy to occur due to incomplete combustion and black smoke. , high pollutant emissions. The system includes an ultrasonic emulsification tank, a heat tracing oil circuit, a combustion chamber, an ultrasonic generator, and an ultrasonic atomization nozzle. One side of the ultrasonic emulsification tank is an oil inlet, and the other side is connected with a heat tracing oil circuit. A heater is arranged below; the ultrasonic atomizing nozzle includes an atomizing air outer cavity, an oil cavity, an atomizing air inner cavity, and an ultrasonic oil-gas mixing oscillation cavity. The invention utilizes an ultrasonic emulsification tank to perform ultrasonic emulsification treatment on the pyrolysis oil before the pyrolysis oil is atomized, thereby improving the properties of the pyrolysis oil and reducing the viscosity of the pyrolysis oil. At the same time, the heat tracing oil circuit and the special atomizing nozzle structure are suitable for viscous pyrolysis oil.

Description

A kind of ultrasonic atomization combustion system and method suitable for pyrolysis oil

technical field

The invention belongs to the field of biomass pyrolysis oil, and in particular relates to an ultrasonic atomization combustion system and method suitable for pyrolysis oil.

Background technique

Biomass pyrolysis oil has high calorific value and oxygen content, and is one of the important objects of renewable energy technology research. However, biomass pyrolysis oil has problems such as high viscosity and many impurities, which hinder its resource utilization. At present, the methods for upgrading and modifying biomass tar mainly include emulsification method and chemical method, among which the chemical method has the problems of complicated process and high modification cost.

Ultrasonic emulsification is a simple and low-cost oil modification method. Under the action of ultrasonic waves, the two immiscible liquids and the surfactant destroy the original intermolecular surface tension of the solution due to the ultrasonic cavitation effect, and promote the mutual dissolution of the two liquids to form a stable emulsion, which can reduce the amount of pyrolysis oil. Viscosity, improve the combustion performance and energy grade of bio-tar.

For high-viscosity liquid fuels such as biomass pyrolysis oil, nozzle technology is the core of atomization combustion technology. The performance of the nozzle directly affects the atomization effect and the service life of the nozzle itself, which is related to the normal and stable operation of the combustion process. Due to the characteristics of high viscosity, high density, high surface tension and difficult atomization of biomass pyrolysis oil, there are few nozzles that can be applied to biomass pyrolysis oil at present.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an ultrasonic atomization combustion system suitable for pyrolysis oil, so as to solve the problems of incomplete combustion, black smoke and high pollutant discharge that are easy to occur in the current pyrolysis oil combustion system during operation.

The technical scheme of the present invention is as follows: an ultrasonic atomization combustion system suitable for pyrolysis oil, comprising an ultrasonic emulsification tank, a heat tracing oil circuit, a combustion chamber, an ultrasonic generator, and an ultrasonic atomizing nozzle, and the end of the heat tracing oil circuit is connected with ultrasonic mist The outlet end of the ultrasonic atomizing nozzle is inserted into the combustion chamber, and the ultrasonic atomizing nozzle is also connected to an ultrasonic generator; one side of the ultrasonic emulsification tank is an oil inlet, and the other side is connected with a heat tracing oil circuit. A heater is provided below; the ultrasonic atomizing nozzle includes an atomizing air outer cavity, an oil cavity, an atomizing air inner cavity, and an ultrasonic oil-gas mixing oscillation cavity. The outermost layer is the atomizing air outer cavity, and the middle layer is the oil cavity. The innermost layer is the atomizing air inner cavity, the front end of the outer atomizing air cavity is provided with an atomizing air through hole, the swirl nozzles are evenly arranged around the inclined surface of the constricted end of the oil cavity, and the outer wall of the ultrasonic oil-gas mixing oscillation cavity is provided with ultrasonic oscillation. device.

Further, there are 8-12 swirl nozzles, and swirl grooves are arranged on both sides of each nozzle.

Further, there are two heat tracing oil circuits, both of which are provided with basket filters, and an oil pressure pump is also provided on the heat tracing oil circuits.

Further, the inside of the heat tracing oil circuit is a pipeline, and the outside is provided with a heating insulation layer.

Carry out the method for atomization combustion with the above-mentioned ultrasonic atomization combustion system applicable to pyrolysis oil, it is characterized in that comprising the following steps:

A. Select biomass pyrolysis oil with a volume content of 45-55%, methanol with a volume content of 10-20%, and diesel oil with a volume content of 35-45%, evenly mix them into the ultrasonic emulsification tank, and set the heater to heat The temperature is 80-100°C, connect the oil circuit; turn on the power of the ultrasonic generator, set the ultrasonic power density to 0.9-0.95W/mL, and the ultrasonic action time to 17-23min; use ultrasonic emulsification to emulsify the mixture into pyrolysis oil - diesel emulsion;

B. Open the air compressor and air storage tank, and fill the air as atomizing agent into the ultrasonic atomizing nozzle through the heat tracing air circuit; open the oil circuit and oil pressure pump to adjust the atomization pressure of biomass pyrolysis oil; open the ultrasonic generator Connected to the switch of the ultrasonic oscillator in the nozzle, the pyrolysis oil is broken into droplets smaller than 10um after entering the three-stage ultrasonic atomizing nozzle;

The first atomization occurs between the outer cavity of the atomizing air and the oil cavity. After the pyrolysis tar passes through the oil cavity, it is ejected by the annularly arranged swirl nozzle.

The second atomization occurs between the inner cavity of the atomizing air and the nozzle shell. After passing through the inner cavity of the atomizing air, the high-pressure air is mixed with the first atomized droplets, and the droplets are atomized for the second time. After the oil mist enters the ultrasonic oil-gas mixing oscillation cavity,

Under the action of the ultrasonic oscillator, it is squeezed and guided by the ultrasonic oil-gas mixing oscillating cavity and the ultrasonic oscillator for the third atomization, and then sprayed out through the main nozzle;

C. The droplet particles are sprayed into the combustion chamber of the burner, and the igniter is turned on for ignition and combustion; the high-pressure fan and the tube heat exchanger are turned on to exchange heat between the burner and the flue gas. The high-pressure fan and the temperature signal adopt the closed-loop control principle to ensure The flue gas outlet temperature is below 200°C.

Further, the composition of the mixed oil added to the ultrasonic emulsification tank is biomass pyrolysis oil with a volume content of 55%, a volume content of 10% co-emulsion methanol, and a volume content of diesel oil with a volume content of 35%.

The mechanism of the invention is as follows: the pyrolysis oil ultrasonic atomization combustion system reduces the viscosity of the pyrolysis oil through ultrasonic emulsification, improves the atomization properties of the pyrolysis oil, and uses the ultrasonic three-stage atomization to greatly improve the pyrolysis oil emulsifier. The atomization effect of the pyrolysis oil emulsifier is atomized into tiny droplet particles, which are fully burned in the combustion chamber and the flue gas heat exchange, which can effectively achieve high-efficiency combustion and low pollution emissions.

The characteristics of the present invention are as follows:

(1) The pyrolysis oil is ultrasonically emulsified before the pyrolysis oil is atomized by the ultrasonic emulsification tank, which improves the properties of the pyrolysis oil and reduces the viscosity of the pyrolysis oil. At the same time, the heat tracing oil circuit and the special atomizing nozzle structure are suitable for viscous pyrolysis oil.

(2) The ultrasonic atomizing nozzle has a special three-stage atomization structure, and the atomization method combining internal mixing air atomization and ultrasonic atomization makes the pyrolysis oil fully atomized, the atomized particles are small, and the atomization is uniform. The pyrolysis oil burner with ultrasonic atomizing nozzle is easy to ignite, the fire is even, the combustion is complete, and the black smoke is less.

(3) The ultrasonic ultrasonic atomization combustion system can continuously carry out the three processes of ultrasonic emulsification, atomization and combustion of pyrolysis oil, realizing the continuity and integration of the reforming and combustion process of pyrolysis oil, and reducing the treatment of pyrolysis oil. and pollution during transportation.

Description of drawings

1 is a schematic structural diagram of an ultrasonic atomization combustion system suitable for pyrolysis oil;

2 is a schematic structural diagram of an ultrasonic atomizing nozzle in an ultrasonic atomizing combustion system suitable for pyrolysis oil;

FIG. 3 is a side view of FIG. 2 .

The meanings of the reference numerals are as follows: 1-ultrasonic emulsification tank; 2-heat tracing oil circuit; 3-basket filter; 4-hydraulic pump; 5-ultrasonic atomizing nozzle; 6-combustion chamber; 7-ultrasonic generator; 8-Tracking gas path; 9-Air storage tank; 10-Air compressor; 11-Heater; 12-Ultrasonic transducer; 21-Heating insulation layer; 50-Swirl tank; 51-Swirl nozzle; 52- Atomizing air outer cavity; 53-Oil cavity; 54-Nozzle shell; 55-Atomizing air inner cavity; 56-Atomizing air through hole; 57-Ultrasonic oscillator; 58-Ultrasonic oil-gas mixing cavity; 59-Total nozzle ; 61 - combustion chamber; 62 - heat exchange air outlet; 63 - tube heat exchanger; 64 - flue gas outlet; 65 - flame observation hole; 66 - high pressure fan; 67 - blower.

Detailed ways

The present invention will be described in further detail below with reference to the accompanying drawings.

As shown in Figure 1, an ultrasonic atomization combustion system suitable for pyrolysis oil includes ultrasonic emulsification tank 1, heat tracing oil circuit 2, combustion chamber 6, ultrasonic generator 7, ultrasonic atomizing nozzle 5, heat tracing oil The end of the road 2 is connected to the ultrasonic atomizing nozzle 5 , the outlet end of the ultrasonic atomizing nozzle 5 is inserted into the combustion chamber 6 , and the ultrasonic atomizing nozzle 5 is also connected to the ultrasonic generator 7 . The left side of the ultrasonic emulsification tank 1 is the oil inlet, and the right side is connected with the heat tracing oil circuit 2. The heater 11 is installed under the ultrasonic emulsification tank 1 to provide a higher temperature environment for the emulsifier in the emulsification tank. The ultrasonic generator 7 is connected to the ultrasonic emulsification tank 1 through the ultrasonic transducer 12 . The inside of the heat tracing oil circuit is a pipeline, and the outside is attached with a heating insulation layer 21, which can maintain a higher temperature of the emulsifier, improve the fluidity of the emulsifier, and prevent condensation and blockage. Basket filters 3 are arranged on the two branches of the heat tracing oil circuit to filter the impurities of the emulsifier and prevent the nozzle from being blocked. A hydraulic pump 4 is also installed on the heat tracing oil circuit to control the atomization pressure of the emulsifier. An ultrasonic atomizing nozzle 5 is connected to the end of the heat tracing oil circuit 2 .

The ultrasonic atomizing nozzle 5 includes an atomizing air outer cavity 52, an oil cavity 53, an atomizing air inner cavity 55, and an ultrasonic oil-gas mixing oscillation cavity 58. The outermost layer is the atomizing air outer cavity 52, the middle layer is the oil cavity 53, and the most The inner layer is the atomizing air inner cavity 55, the front end of the atomizing air outer cavity 52 is provided with an atomizing air through hole 56, the swirl nozzle 51 is evenly arranged around the inclined surface of the constricted end of the oil cavity 53, and the ultrasonic oil-gas mixing oscillation cavity 58 The outer wall is provided with an ultrasonic oscillator 57 .

The outlet of the ultrasonic atomizing nozzle 5 is inserted into the combustion chamber 6 . An igniter is arranged below the ultrasonic atomizing nozzle 5 to ignite the oil mist, so that the oil mist is fully burned in the combustion chamber 61 within the combustion chamber. The top of the combustion chamber 6 is equipped with a heat exchange air outlet 62, and a tube heat exchanger 63 is installed inside. The side end of the combustion chamber 6 is provided with a flue gas outlet 64, and the hot flue gas flows through the inside of the tube heat exchanger 63, The cold air flows through the outside of the tube heat exchanger 63 to achieve efficient heat exchange of the flue gas. The combustion chamber is also provided with a flame observation hole 65 for observing the length of the flame and checking the combustion state; a high-pressure fan 66 and a blower 67 are arranged below the combustion chamber, which can increase the contact amount of oxygen and atomized droplets, making it more fully burned , and can accelerate the heat exchange of flue gas.

Principle of ultrasonic atomizing nozzle: It adopts the combination of internal mixing air atomization and ultrasonic oscillation atomization. 58. From the radial point of view, the outermost layer is the atomizing air outer cavity 52, the middle layer is the oil cavity 53, and the innermost layer is the atomizing air inner cavity 55, in which the constriction end of the oil cavity 53 is evenly arranged around the inclined surface 8-12 a swirl nozzle 51 . The first atomization occurs between the atomizing air outer cavity 52 and the oil cavity 53, and the pyrolysis tar passes through the oil cavity 53 and is sprayed out by the annularly arranged swirl nozzles 51, and swirl grooves 50 are arranged on both sides of each nozzle. The high-pressure air in the outer cavity of the atomizing air collides with the pyrolysis tar droplets ejected by the swirl nozzle 51 through the swirl groove 50 to form a primary atomization; the second atomization occurs between the inner cavity 55 of the atomizing air and the nozzle shell Between 54 and 54, the high-pressure air passes through the atomizing air cavity 55 and is mixed with the first atomized droplets, and the droplets are atomized a second time. Under the action of the oscillator 57, it is squeezed and guided by the mixing cavity 58 and the ultrasonic oscillator 57, and is atomized for the third time, and further atomized into smaller particles, which are then sprayed out through the total nozzle 59. The pyrolysis tar droplets undergo three atomization processes to achieve a better atomization effect.

Example 1

When the equipment is working, select biomass pyrolysis oil with a volume content of 55%, methanol with a volume content of 10%, and diesel oil with a volume content of 35%, evenly mix them into the ultrasonic emulsification tank, and set the heating temperature of the heater to 80 °C. , connect the oil circuit; turn on the power of the ultrasonic generator 7, set the ultrasonic power density to 0.9W/mL, and the ultrasonic action time to 17min. The mixed solution was emulsified into a pyrolysis oil-diesel emulsion by ultrasonic emulsification. Turn on the air compressor 10 and the air storage tank, and fill the ultrasonic atomizing nozzle 5 with air as an atomizing agent through the heat tracing gas path 8 . Open the oil circuit and hydraulic pump to adjust the atomization pressure of biomass pyrolysis oil. Turn on the switch of the ultrasonic generator connected to the ultrasonic oscillator 57 in the nozzle, and the pyrolysis oil will be broken into droplets smaller than 10um after entering the three-stage ultrasonic atomizing nozzle. After that, it is injected into the combustion chamber of the burner, and the igniter is turned on for ignition and combustion; the high-pressure fan 66 and the tube heat exchanger 63 are turned on to exchange heat between the burner and the flue gas. The high-pressure fan and the temperature signal adopt the closed-loop control principle to ensure the flue gas. The outlet temperature is below 200°C. Arrange 12 swirl nozzles

Ultrasonic emulsification treatment in embodiment 2-ultrasonic emulsification tank:

Eight swirl nozzles were arranged; the volume content of biomass pyrolysis oil was 45%, the volume content of methanol as co-emulsion agent was 10%, and the volume content of diesel oil was 45%. The mixed solution was injected into the ultrasonic emulsification tank 1 . The ultrasonic generator sets the ultrasonic power density to 0.95W/mL, the ultrasonic action time to 23min, and the heater temperature to 100°C. When high-intensity ultrasonic waves act on the pyrolysis oil, there is a certain shear stress in the pyrolysis oil. Under the action of shear stress, the pyrolysis oil, co-emulsion agent and diesel oil are fully mixed to emulsify the pyrolysis oil, and when the phase concentration reaches a certain value, the emulsion type of the pyrolysis oil is changed to reduce its viscosity.

Claims (6)

1. An ultrasonic atomization combustion system suitable for pyrolysis oil, comprising an ultrasonic emulsification tank (1), a heat tracing oil circuit (2), a combustion chamber (6), an ultrasonic generator (7), an ultrasonic atomization nozzle ( 5), the end of the heat tracing oil circuit (2) is connected to the ultrasonic atomizing nozzle (5), the outlet end of the ultrasonic atomizing nozzle (5) is inserted into the combustion chamber (6), and the ultrasonic atomizing nozzle (5) is also connected to the ultrasonic generator ( 7); characterized in that: one side of the ultrasonic emulsification tank (1) is an oil inlet, the other side is connected with a heat tracing oil circuit (2), and a heater (11) is provided below the ultrasonic emulsification tank (1). ; The ultrasonic atomizing nozzle (5) comprises an atomizing air outer cavity (52), an oil cavity (53), an atomizing air inner cavity (55), an ultrasonic oil-gas mixing oscillation cavity (58), and the outermost layer is an atomizing air cavity (53). The air outer cavity (52), the middle layer is the oil cavity (53), the innermost layer is the atomizing air inner cavity (55), and the front end of the atomizing air outer cavity (52) is provided with an atomizing air through hole (56), The swirl nozzles (51) are evenly arranged around the inclined surface of the constricted end of the oil cavity (53), and an ultrasonic oscillator (57) is arranged on the outer wall of the ultrasonic oil-gas mixing oscillation cavity (58). 2 . The ultrasonic atomization combustion system suitable for pyrolysis oil according to claim 1 , wherein the swirl nozzles ( 51 ) are 8-12, and swirl grooves are arranged on both sides of each nozzle. 3 . (50). 3. An ultrasonic atomization combustion system suitable for pyrolysis oil according to claim 1 or 2, characterized in that: the heat tracing oil circuit (2) is two, and a basket filter is provided on both of them. (3), and a hydraulic pump (4) is also provided on the heat tracing oil circuit. 4 . The ultrasonic atomization combustion system suitable for pyrolysis oil according to claim 3 , characterized in that: the heat tracing oil circuit ( 2 ) has a pipeline inside and a heating insulation layer ( 21 ) outside. 5 . 5. carry out the method for atomization combustion with a kind of ultrasonic atomization combustion system that is applicable to pyrolysis oil according to claim 1, it is characterized in that comprising the steps: A. Select biomass pyrolysis oil with a volume content of 45-55%, methanol with a volume content of 10-20%, and diesel oil with a volume content of 35-45%, evenly mix them into the ultrasonic emulsification tank, and set the heater to heat The temperature is 80-100°C, connect the oil circuit; turn on the power of the ultrasonic generator (7), set the ultrasonic power density to 0.9-0.95W/mL, and the ultrasonic action time to be 17-23min; use ultrasonic emulsification to emulsify the mixture into Pyrolysis oil-diesel emulsion; B. Open the air compressor (10) and the air storage tank (9), and use the air as an atomizing agent to fill the ultrasonic atomizing nozzle (5) through the heat tracing air circuit (8); open the oil circuit and the oil pressure pump, adjust the production Substance pyrolysis oil atomization pressure; open the switch of the ultrasonic generator connected to the ultrasonic oscillator (57) in the nozzle, the pyrolysis oil enters the three-stage ultrasonic atomization nozzle and is broken into droplets smaller than 10um; the first time Atomization occurs between the atomizing air outer cavity (52) and the oil cavity (53), and the pyrolysis tar passes through the oil cavity (53) and is ejected by the annularly arranged swirl nozzle (51); the second atomization occurs Between the inner cavity of the atomizing air (55) and the nozzle shell (54), the high-pressure air passes through the inner cavity of the atomizing air (55) and is mixed with the first atomized droplets, and the droplets are atomized for the second time. After the secondary atomization, the oil mist enters the ultrasonic oil-gas mixing oscillation chamber (58); under the action of the ultrasonic oscillator (57), the oil mist is squeezed and guided by the ultrasonic oil-gas mixing oscillation chamber (58) and the ultrasonic oscillator (57), and the The third atomization is sprayed out through the main nozzle (59); C. The droplet particles are sprayed into the combustion chamber of the burner, and the igniter is turned on for ignition and combustion; The closed-loop control principle is adopted to ensure that the flue gas outlet temperature is below 200 °C. 6. method according to claim 5, is characterized in that: the composition that adds the mixed oil of ultrasonic emulsification tank is biomass pyrolysis oil that volume content is 55%, and volume content is 10% co-emulsion methanol, and volume content is 35%. % diesel.

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