JPH06154668A - Atomizing method for highly viscous liquid and device therefor - Google Patents

Abstract

PURPOSE:To atomize a highly viscous liquid by a simple constitution by forming gas-liquid two phase flow so that the highly viscous liquid introduced into a pipe line flows along the pipe wall in annular flow and the gas flows in the central part of the pipe line and atomizing the highly viscous liquid with the low pressure gas by a spray nozzle. CONSTITUTION:The highly viscous liquid having 100-10000 centipoise is supplies at an optional position distant sufficiently from the spray nozzle 7 to a pipe line at the tip part of which the nozzle 7 is provided from a feed tank 1 through a pump 3 as a liquid flow and the gas is introduced at the middle of the pipe line. A stationary gas-liquid two phase flow is formed so that the highly viscous liquid flows along the pipe wall in annular flow and the gas flows in the central part of the pipe line, reaches the spray nozzle 7 through a relief valve 8 and by the spray nozzle 7, the highly viscous liquid is sprayed and atomized with the low pressure gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for atomizing a high viscosity liquid into fine particles. More specifically, the viscosity is 10
The present invention relates to a method for atomizing a high-viscosity liquid of 0 to 10000 cp using a spraying device of a one-fluid nozzle. The present invention also relates to a spraying device having a one-fluid nozzle for atomizing a high-viscosity liquid having a viscosity of 100 to 10,000 cp.

[0002]

BACKGROUND OF THE INVENTION The atomization of low viscosity liquids into aerosols is often practiced, for example by spray coating, fuel injection, spray drying,
It is already well established in chemical spraying, spray painting and many other fields of application.

However, the viscosity is 100 to 1000.
In order to atomize a high-viscosity liquid such as 0 cp into fine particles, it is not possible to directly apply such a low-viscosity liquid spraying technique, and thus various methods have been proposed so far for spraying a high-viscosity liquid. ing. These methods include 1) a method of lowering the liquid viscosity to at least 100 cp by heating or adding a solvent, 2)
In the case of using a one-fluid nozzle, there was a method of applying a high pressure of 100 atm or more to the liquid supply, and 3) a method of spraying gas in combination with a two-fluid nozzle or a three-fluid nozzle.

However, the following problems exist in any of these methods. That is, 1) the method of heating cannot be applied to heat-sensitive substances, and the method of adding a solvent requires post-treatment of desolventization, which is extremely complicated in the process. 2) The method of applying a high pressure has a considerably limited application range, and thus there is a safety problem, and 3) the method of using a gas with a two-fluid nozzle or a three-fluid nozzle is the most common method and has been widely used so far. However, since the gas supply position is limited to one nozzle part, it is often not applicable due to the operation and the structure of the device.Because the gas pressure is relatively high, it is intended for spray coating, etc. When spraying a high-viscosity liquid, there has been a problem that the atomized liquid is scattered over a wide range.

[0005]

Therefore, there is a new method for atomizing a high-viscosity liquid without heating or adding a solvent, without applying high pressure, and without using a two-fluid nozzle or a three-fluid nozzle. Elucidation of technical means is required.

[0006]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that the viscosity is 100 to 1
Under the condition that a high viscosity liquid of 0000 cp and a gas are flown in an annular flow along the pipe wall in a pipe line provided with a spray nozzle at the tip, and the gas flows in the central part of the pipe line at a low pressure. Achieved by introducing the high viscosity liquid and gas into the above-mentioned conduit so as to form a steady gas-liquid two-phase flow, and atomizing the high viscosity liquid from a spray nozzle to form fine particles. The present invention has been completed by finding out that it is possible.

That is, according to the present invention, the viscosity is 100 to 10000 cp at an arbitrary position, which is located at a sufficient distance from the spray nozzle in a pipe line provided with a spray nozzle at the tip.
The high-viscosity liquid and gas are introduced, the high-viscosity liquid flows in an annular flow along the pipe wall, and the gas forms a steady gas-liquid two-phase flow that flows in the central part of the pipe line at low pressure and sprays. The present invention relates to a method of atomizing a high-viscosity liquid together with a gas into fine particles with a nozzle.

Further, according to the present invention, a pipe line for spraying a high-viscosity liquid into particles is provided with a spray nozzle at its tip,
The high-viscosity liquid introduction part and the gas introduction part provided in the conduit at an arbitrary position with a sufficient distance from the spray nozzle, and the high-viscosity liquid introduced into the conduit are directed toward the spray nozzle along the pipe wall. The gas flowing in an annular flow and the gas introduced into the pipeline is forced into the pipeline with a highly viscous liquid and gas for forming a steady gas-liquid two-phase flow that flows toward the spray nozzle in the center of the pipeline. And a spraying device for a high-viscosity liquid.

In the present invention, the high-viscosity liquid is introduced at an arbitrary position with a sufficient distance to a pipe line provided with a spray nozzle at its tip. Although it depends on the viscosity, surface tension and amount of the introduced high-viscosity liquid, the pressure and amount of the introduced gas, and the pipe diameter of the pipeline, the high-viscosity liquid introduced into the pipeline is a steady gas-liquid. The distance required to form a two-phase flow. This distance is, for example, 19 cm or more when introducing a liquid having a viscosity of 2000 cp at a pressure of 0.8 kg / cm ² G and a gas at a pressure of 1.7 kg / cm ² G into a pipe having an inner diameter of 10.9 mm. For example, a pipe with an inner diameter of 10.9 mm should have a viscosity of 40
12 cm or more is required to introduce 00 cp of liquid at a pressure of 1.0 kg / cm ² G and gas at a pressure of 2.0 kg / cm ² G. Since the value varies depending on the viscosity of the high-viscosity liquid and the pressure of the introduced gas, it can be determined in advance by an experimental method.

The spray nozzle may be a one-fluid nozzle having a shape in which the pipe diameter of the pipe line is reduced to form an opening and a cavity (that is, a gas space) is formed and maintained in the center of the nozzle chamber. The high-viscosity liquid that has been conveyed as an annular flow through the pipe line by the spray nozzle having such a shape narrows the flow path, reaches the opening of the spray nozzle, and is atomized by the gas flowing in the cavity at the center of the nozzle chamber to be atomized. It will be.

The high-viscosity liquid which is sprayed into fine particles in the present invention includes high molecular substances such as epoxy resin, phenol aldehyde initial condensate, silicon, polyamic acid, polyvinyl alcohol or their precursors, terpene resin, oleoresin. Perfume materials such as, pharmaceutical substances such as tocopheryl retinoate and tocopheryl acetate, high viscosity chemicals such as glycerin, dextrin and starch syrup, high viscosity petroleum fractions such as tar and heavy oil, atomized by spraying In this case, a highly viscous substance having a viscosity in the range of 100 to 10,000 cp can be mentioned.

As the gas used in the present invention, any gas may be used as long as it is an inert gas with respect to the high-viscosity substance atomized by spraying. In this case, it may be flammable or It must not be combustion-supporting (however, it may be combustion-supporting when a high-viscosity liquid is used as fuel, etc.), and it is of course necessary to consider the environment. . As specific examples of these gases, compressed air, nitrogen gas, carbon dioxide gas, helium gas, propane gas, butane gas or the like can be used.

This high-viscosity liquid has a pressure of 0.2-3.0 kg / cm ² G in a pipe equipped with a spray nozzle at its tip, and a pressure of 0.5-4.5 kg / cm ² G for gas. Will be introduced in.

The pipe line is composed of a pipe body having an inner diameter of 9.4 to 18.4 mm and is elevated from the introduction point of the high viscosity liquid and gas by a distance determined by the viscosity, pressure and introduction amount of the high viscosity liquid and gas. After the viscous liquid flows, the high-viscosity liquid forms a steady gas-liquid two-phase flow that flows in an annular flow along the tube wall.

If desired, the apparatus of the present invention may be provided with a heating device in the middle of the pipeline. The viscosity of the high-viscosity liquid introduced by such a heating device can be reduced, and the sprayed high-viscosity liquid can be further made into fine particles. Furthermore, in order to keep the viscosity of the high-viscosity liquid in the pipeline constant, the entire pipeline can be kept warm by a hot water jacket or a tape heater.

The accompanying drawings are schematic illustrations of apparatus for practicing the present invention. In the drawing, the high-viscosity liquid is supplied from the supply tank 1 via the pump 3 to the conduit as a liquid flow. Gas is introduced in the middle of the pipe, and the liquid flow and the gas flow reach the spray nozzle 7 via the relief valve 8 as a gas-liquid-annular flow, and the high viscosity liquid is sprayed from the spray nozzle 7. In the figure, 2 is a pressure gauge, 4 is a flow meter, 5
Is a thermometer and 6 is a sight glass. With this sight glass, the flow state of the highly viscous liquid can be visually observed. As described above, the device for carrying out the present invention has a very remarkable effect that the high-viscosity liquid can be atomized by appropriately setting the conditions, though the structure is extremely simple.

According to the present invention, a highly viscous liquid can be easily made into fine particles. Therefore, spray coating, particularly coating of fine particles or light weight substances, spray drying, spray painting, microencapsulation, etc. Can be used as a burner for high-viscosity liquid fuel.

Next, the present invention will be specifically described with reference to examples.

[0019]

【Example】

[Example 1] Outer diameter 17.3 mm, inner diameter 10.9 mm, length 25
A 60 mm stainless steel pipe was prepared, and its tip was squeezed to form an opening having an inner diameter of 1.0 mm, which was used as a spray nozzle. The other end of this pipe is connected to a metering pump and is supplied from a feed tank with a 90 wt% glycerin aqueous solution (liquid temperature 20 ° C., viscosity 200 cp, surface tension 62 dyn / cm).
Through a pump, pressure 0.3 kg / cm ² G, flow rate 0.02 m
/ Sec was supplied to this pipe. On the other hand, a gas inlet was provided 1410 mm downstream from the metering pump connecting part of the pipe, and nitrogen gas was supplied from here at a pressure of 1.0 kg / cm ² G and a flow rate of 2.0 m / sec. Glycerin solution is 750mm from the gas inlet
It has been confirmed that an undisturbed annular flow is formed downstream,
Then, the aqueous glycerin solution was directly sprayed from the spray nozzle to obtain stable and uniform fine particles.

Example 2 Using the apparatus described in Example 1, a viscosity standard solution (liquid temperature 25 ° C., viscosity 1000 cp, surface tension 52 dyn / cm) was made into fine particles. That is, this viscosity standard solution was supplied at a pressure of 0.5 kg / cm ² G and a flow rate of 0.04 m / sec, and nitrogen gas was supplied at a pressure of 1.4 kg / cm ² G and a flow rate of 3.2 m / sec. It was confirmed that the viscosity standard solution forms an undisturbed annular flow 240 mm downstream from the gas inlet. The viscosity standard solution was sprayed straight from the tip of the spray nozzle, and stable and uniform fine particles were obtained.

Example 3 Using the apparatus described in Example 1, tocopheryl retinoate (liquid temperature 85 ° C., viscosity 200)
0 cp, surface tension 63 dyn / cm) was made into fine particles. That is, the pressure of this tocopheryl retinoate was 0.8 kg / cm.
² G, flow velocity 0.07 m / sec, nitrogen gas pressure 1.7
It was supplied at kg / cm ² G and a flow rate of 5.1 m / sec. It was observed that tocopheryl retinoate forms an undisturbed annular flow downstream of 190 mm from the gas inlet. Tocopheryl retinoate was sprayed straight from the tip of the spray nozzle, and stable and uniform fine particles were obtained.

Example 4 Using the apparatus described in Example 1, tocopheryl retinoate (liquid temperature 78 ° C., viscosity 400)
0 cp, surface tension 60 dyn / cm) was made into fine particles. That is, the pressure of this tocopheryl retinoate was 1.0 kg / cm.
² G, flow velocity 0.10 m / sec, nitrogen gas pressure 2.0
It was supplied at kg / cm ² G and a flow rate of 6.3 m / sec. Tocopheryl retinoate was found to form an undisturbed annular flow 120 mm downstream from the gas inlet. Tocopheryl retinoate was sprayed straight from the tip of the spray nozzle, and stable and uniform fine particles were obtained.

Comparative Example 1 The procedure of Example 2 was repeated, but the pressure of the viscosity standard solution and nitrogen gas were 1.6 kg / cm ² respectively.
G, flow velocity 0.21 m / sec, and pressure 1.9 kg / cm ² G,
The flow rate was 0.01 m / sec. Under this supply condition, the viscosity standard liquid flow made a bubble flow, reached the spray nozzle, dropped from the tip of the nozzle into a liquid column, and was not atomized.

COMPARATIVE EXAMPLE 2 The procedure of Example 3 is repeated except that the tocopheryl retinoate and nitrogen gas have a pressure of 2.0 kg / cm ² G, a flow rate of 0.45 m / sec, and a pressure of 2.8 kg / cm ² G, respectively. At a flow rate of 0.33 m / sec. Under this supply condition, tocopheryl retinoate formed an intermittent flow, was discharged to the spray nozzle from the tip of the nozzle in the form of non-uniform fine particles or liquid column, and the fine particles were only intermittently formed.

[Brief description of drawings]

1 is a diagram schematically showing an apparatus for carrying out the present invention.

Claims (2)

[Claims] 1. A high viscosity liquid and a gas having a viscosity of 100 to 10000 cp are introduced into a pipe line provided with a spray nozzle at a tip portion at an arbitrary position with a sufficient distance from the spray nozzle. A method of forming a steady gas-liquid two-phase flow that flows in the central part of the pipe, flowing in an annular flow along the pipe wall, and spraying a high-viscosity liquid with a low-pressure gas into fine particles. 2. A pipeline having a spray nozzle at its tip, a high-viscosity liquid introducing section and a gas introducing section provided in a pipeline at an arbitrary position with a sufficient distance from the spray nozzle, and a pipeline. The high-viscosity liquid introduced into the pipe flows in an annular flow along the pipe wall toward the spray nozzle, and the gas introduced into the pipe line flows toward the spray nozzle in the central part of the pipe line. An apparatus for spraying a high-viscosity liquid, comprising a high-viscosity liquid for forming a flow and a means for pressurizing a low-pressure gas into a pipeline.