JP2569845B2 - Liquid fuel evaporator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a liquid fuel evaporator for evaporating atomized liquid fuel with high-temperature air and subjecting it to combustion in a burner.

<Prior art and its problems> Conventionally, as a method for evaporating a liquid fuel such as kerosene, apparatuses for evaporating liquid fuel by impinging droplets of the liquid fuel on an inner wall surface or the like of a heated evaporation container are provided. However, there is a problem that tar-like substances are easily generated in the above-mentioned apparatus. To this end, the applicant has provided, in an application filed on the same date as the present specification, a device for directly evaporating atomized liquid fuel atomized by hot air. In this system, liquid fuel is heated to a relatively low temperature (120 ° C).
(About 250 ° C.), which has the effect of suppressing the generation of tar-like substances.

However, in this device of direct evaporation type using hot air,
In the evaporating vessel into which the high-temperature air is introduced, the atmospheric temperature in the inside easily reaches a temperature sufficient for evaporating the liquid fuel, but the temperature (wall temperature) of the evaporating vessel itself is relatively hard to rise, so that the evaporation starts. In the early stage, there was a problem that the evaporated fuel hits the wall surface and condenses. Further, if ignition and extinguishing by the burner occur frequently within a short time, there is a problem that white smoke and odor are likely to be generated.

Therefore, the present invention solves the above problems, and in the case of evaporating liquid fuel with high-temperature air, the condensation of the evaporated fuel is suppressed, so that even if ignition and extinguishing of the burner occur frequently in a short time, white smoke or odor is generated. It is an object of the present invention to provide a liquid fuel evaporator having excellent transient characteristics.

<Means for Solving the Problems> In order to achieve the above object, the liquid fuel evaporating apparatus of the present invention comprises an evaporating container 10 having an evaporating chamber 20 inside, and a harmful evaporating container 10
A spray nozzle 30 for atomizing and spraying the liquid fuel therein, and a high-temperature air feeding means 40 for feeding high-temperature air into the evaporation container 10, and the liquid fuel sprayed in the evaporation container 10 is fed therein. Liquid fuel evaporator directly evaporating and mixing with the high-temperature air, and sending the mixture to the burner 60 side, wherein the high-temperature air feeding means 40 burns fuel in a separate path from the burner 60. A single burner 41 for generating combustion exhaust gas and a means for mixing air with the generated combustion exhaust gas are provided, and after starting operation of the apparatus, before starting introduction of high-temperature air and liquid fuel into the evaporation container 10. The control unit is such that the combustion exhaust gas generated by the burner 41 of the high-temperature air feeding means 40 during the preparation period is directly introduced into the evaporating vessel 10 during the preparation period.
The feature is that 70 is provided.

<Operation> According to the above-mentioned feature of the present invention, after the operation of the apparatus is started, first, a high-temperature flue gas (having a considerably higher temperature than hot air to be introduced later) is first introduced into the evaporation vessel. As a result, the evaporating vessel is heated to a temperature at which fuel does not condense. Then, high-temperature air in which air is mixed into the combustion exhaust gas is sent to the evaporating container, and the liquid fuel is sprayed. Therefore, when the liquid fuel is evaporated, the evaporating container has a sufficient temperature, and no condensation occurs.

<Embodiment> Fig. 1 shows a device according to the present invention. Fig. 1 (A) is a longitudinal sectional view, and Fig. 1 (B) is a partial sectional left side view.

An evaporation chamber 20 is formed in the evaporation container 10, and an ejection nozzle 30 for ejecting a liquid fuel, for example, kerosene, in an atomized state faces the evaporation chamber 20. Further, high-temperature air feeding means 40 for feeding high-temperature air to the evaporation chamber 20 is provided.

It is sent from the constant oil level unit 50 by the pump 51, and the jet nozzle 30
The atomized liquid fuel sprayed from is brought into contact with the high-temperature air from the high-temperature air feeding means 40, evaporates, and is guided to the burner 60 through the delivery pipe 61 in a state of being mixed with the high-temperature air. The particle size of the ejected liquid fuel is, for example, several microns to several tens microns. The high-temperature air sent into the evaporation chamber 20 is set at, for example, 200 ° C. to 400 ° C. In this way, the sprayed liquid fuel is 120 ℃ ~ 250 ℃
Evaporates at moderate temperatures.

The high-temperature air feeding means 40 includes a small burner 41 provided separately from the burner 60, a fuel supply unit 42 for the small burner 41, a combustion chamber 43 formed on the small burner 41, and a combustion chamber 43. Air introduction chamber 44 surrounding 43 and feed pipe 45
And an air supply device for the small burner 41 and the air introduction chamber 44
46 and The air passage from the air supply 46 is divided into a small burner air passage 46a and an air introduction chamber air passage 46b.
An air control valve 47 is provided in the air passage 46b for the air introduction chamber. The air introduction chamber 44, the air supply device 46, the air passage 46b for the air introduction chamber, and the air control valve 47 constitute means for mixing air with the combustion exhaust gas generated by the small burner 41. 48 is an igniter and 49 is a flame detector.

70 is a control unit that controls the operation timing of the entire device,
Fuel supply 42, air supply 46, air control valve 47, igniter 4
8. Control the operation timing of the flame detector 49, the pump 51, and the like.

In the present invention, after the operation is started, before the high-temperature air and the spray fuel are introduced into the evaporating container 10, a preparation period for a certain period of time for introducing the combustion exhaust gas generated by the small burner 41 as it is into the evaporating container 10 is provided. The inner wall of the evaporating vessel 10 is heated by the high-temperature flue gas introduced during the preparation period, and the temperature is raised to a temperature at which the evaporated fuel does not condense. Since the temperature of the combustion exhaust gas is 1200 ° C. to 2000 ° C., the preparation period required for raising the inner wall temperature of the evaporation container 10 to a temperature at which condensation does not occur, for example, to around 110 ° C., may be short.
Needless to say, an appropriate fixed time is selected in advance for the preparation period depending on the size of the evaporation container 10 and the amount of fuel exhaust gas.

The operation timing of the operation by the control unit 70 will be further described with reference to FIG.

Now, when the operation of the apparatus is started, first, air is supplied from the air supply unit 46 to the small burner 41 via the control unit 70, and the igniter 48 is operated. At this time, the air control valve 47 is closed. After a short time, the fuel supply via the control unit 70
42 is activated and fuel is sent to the small burner 41. A gaseous fuel may be sent from the fuel supply unit 42, or a liquid fuel vaporized may be sent from the fuel supply unit 42. Flame detector 49
When the ignition of the small burner 41 is confirmed, the timer in the control unit 70 is activated, and a preparation period for a fixed time is started. During this preparation period, the high-temperature exhaust gas generated in the combustion chamber 43 by the combustion of the small burner 41 passes through the feed pipe 45 as it is and the evaporating vessel.
10 and heats the inner wall of the evaporation container 10. Since the exhaust gas itself is at a very high temperature (1200 ° C. to 2000 ° C.), the temperature (110 ° C.) at which the inner wall of the evaporation vessel 10 does not condense in a short time
(Near). When the preparation period ends, the air control valve 47 is opened via the control unit 70, and the air from the air supply unit 46 is supplied to the air introduction chamber 44. As a result, fresh air from the air introduction chamber 44 is mixed into the combustion exhaust gas of the combustion chamber 43 and is turned into high-temperature air. This high-temperature air is adjusted to 200 ° C. to 400 ° C. and sent into the evaporation container 10. On the other hand, the pump 51 has a pre-purge period from ignition set in advance by the control unit 70 so as to start operation with a slight delay after the preparation period ends,
The liquid fuel starts to be sent at the same time as the end of the pre-purge period. As a result, the spraying of the liquid fuel by the ejection nozzle is started slightly after the introduction of the high-temperature air, and the evaporation is started.

If there is no preparation period for directly introducing the combustion exhaust gas, the pre-purge period until the spraying of the liquid fuel is started, because high-temperature air of about 200 ° C. to 400 ° C. will be introduced into the evaporation container 10. However, a short rise in temperature of the evaporation container 10 cannot be expected, and there is a risk of condensation of the liquid fuel once evaporated.

The evaporating vessel 10 is composed of a cylindrical outer cylinder and disk-shaped end walls 12 and 13, and a jet nozzle 30 is attached to one end wall 13 so as to face the center axis of the outer cylinder 11. . The feed pipe 45 and the feed pipe 61 are tangentially connected to the outer cylinder 11, and the high-temperature air that has entered the evaporating vessel 10 (evaporation chamber 20) from the feed pipe 45 flows spirally into the feed pipe 61. Leaked to Then, it comes into contact with the liquid fuel sprayed in the meantime and evaporates it.

<Effect> According to the liquid fuel evaporator according to the first aspect of the present invention, the present invention has the above-described configuration. As the high-temperature air feeding means 40, the fuel is burned in a different path from the burner 60 to generate combustion exhaust gas. One burner 41 and a means for mixing air with the generated flue gas are provided, and a certain period of time before starting the introduction of high-temperature air and liquid fuel into the evaporation vessel 10 after the operation of the apparatus is prepared. As a period, a control unit which guides the combustion exhaust gas generated by the burner 41 of the high-temperature air feeding means 40 during the preparation period directly into the evaporation container 10
Since the fuel tank 70 is provided, the burner 41 of the high-temperature air feeding means 40 is provided before the evaporation of the liquid fuel in the evaporation container 10 is started.
The evaporating container 10 can be sufficiently heated by the combustion exhaust gas generated in the above. Therefore, condensation of the evaporated liquid fuel can be reliably prevented, and the generation of white smoke and odor can be suppressed even if the combustor using the present device is frequently ignited and extinguished in a short time.

Of course, since the liquid fuel is directly evaporated from the atomized state by the high-temperature air, the evaporation temperature is lowered, and the generation of tar-like substances in the evaporation container is suppressed.

[Brief description of the drawings]

FIG. 1 shows an apparatus according to the present invention, FIG. 1 (A) is a longitudinal sectional view, FIG. 1 (B) is a partially sectional left side view, and FIG. 10: Evaporation vessel 20: Evaporation chamber 30: Jet nozzle 40: Hot air sending means 41: Small burner 42: Fuel supply 43: Combustion chamber 44: Air introduction chamber 46: Air supply 47: Air control valve 50: Constant oil Faceplate 60: Burner 70: Control unit

Claims (1)

(57) [Claims] An evaporating container having an evaporating chamber therein, and a jet nozzle for atomizing and spraying liquid fuel into the evaporating container.
30 and a high-temperature air feeding means 40 for feeding high-temperature air into the evaporating container 10, and the liquid fuel sprayed in the evaporating container 10 is directly evaporated and mixed with the sent high-temperature air in the evaporating container 10. A liquid fuel evaporating device configured to feed the fuel to the burner 60 side, wherein the high-temperature air feeding means 40 includes a single burner 41 that burns fuel in a different path from the burner 60 to generate combustion exhaust gas; Means for mixing air with the generated combustion exhaust gas, and a certain period of time after the start of operation of the apparatus and before the start of introduction of high-temperature air and liquid fuel into the evaporation container 10 as a preparation period, and during the preparation period, A liquid fuel evaporating apparatus, further comprising a control unit 70 for guiding the combustion exhaust gas generated by the burner 41 of the high-temperature air feeding means 40 into the evaporation container 10 as it is.