JPS5986893A - Evaporation by heat exchanger of double tube type - Google Patents

Abstract

PURPOSE:To perform evaporation, preventing pulsation, in the titled heat exchanger, by giving a stirring action to the flow in the middle of a flow path for a fluid to be heated, and by letting the heated fluid pass through a nozzle at the end of a flow path. CONSTITUTION:A heat exchanger 1 of double tube type, of which outer side of an inner tube 11 is wrapped with a jacket 12, is constituted in such a manner that a nozzle 3 is provided at the end of a flow path 2 for a fluid to be heated, and at least one orifice 4 is interposed in the middle part of a flow path 2. A line mixer, a baffle plate, a filler of any kind, or a nozzle can be substituted for the orifice. That is, any thing which is located in the flow path and can stir the fluid flow and give proper resistance to it is usable. An apparatus is constituted by connecting a plurality of unit heat exchangers 1 by pipe bends 6. The numerical 7 represents a rated pump to feed liquid to be evaporated, the numerical 8 represents an inlet for a heating medium, and the numerical 9 represents an outlet for the heating medium.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved evaporation method and apparatus using a double tube heat exchanger.

Double-tube heat exchangers, in which the heated fluid flows inside the inner and outer double pipes and the heating medium flows through the outer jacket, are used in many applications because they have a simple structure and are easy to manufacture and use. It is being

One of them is its use as an evaporator.

In this case, in order to ensure the necessary heat transfer area, a large number of unit heat exchangers are connected in series to configure the evaporator. However, this evaporator has a problem in that pulsation occurs depending on the conditions of use.

As a means to prevent pulsation, an enlarged part is provided in the flow path of the heated fluid to be evaporated, and this is partitioned into two stages, for example, so that the fluid passes through a large number of pores between each partition. is being established. However, although this device has a large pressure loss, its pulsation prevention effect is low. In addition, a bypass is provided in the flow path of the heated fluid,
There is also a method of connecting expansion chambers, but these methods are recommended when dealing with fluids that have high boiling points or low volatility and that remain in a liquid or solid state even after passing through the evaporator. Reluctantly volatile components remain there, which is disadvantageous.

The present inventor has attempted to solve these problems, to enable effective pulsation prevention with a low pressure loss with a simple configuration, and to avoid retention of hardly volatile components. Through research, we have arrived at the present invention.

In the evaporation method of the present invention, in evaporation using a double tube heat exchanger, a disturbance effect is applied to the flow of the fluid to be heated in the middle of the flow path, and the heated fluid is passed through a nozzle at the end of the flow path. It is characterized in that evaporation is carried out while preventing pulsation by allowing the water to pass through.

Further, in the double-tube heat exchanger type evaporator of the present invention for carrying out the above-mentioned evaporation method, typically, as shown in FIG. A nozzle 3 is installed at the end of the heated fluid flow path 2 of the wrapped double-tube heat exchanger 1.
It has a structure in which at least one orifice 4 is inserted in the middle. The orifice can also be replaced by a line mixer, a jammer plate, various fillers, a nozzle, etc. In short, any of these may be used as long as they are present in the flow path and provide appropriate resistance and disturb the flow of fluid. In Fig. 1, the device is composed of a plurality of unit heat exchangers 1 connected by bends 6, 7 is a metering pump that supplies the liquid to be evaporated, 8 is a heating medium inlet, and 9 is a heating medium outlet. be.

Another example of the evaporator of the present invention is one in which an orifice and a line mixer 5 are used together, as shown in FIG.

According to the present invention, the above-described configuration not only prevents pulsation that tends to accompany evaporation, but also increases the heat transfer coefficient due to the presence of a resistor such as an orifice, thereby improving the performance of the device. This benefit more than compensates for the disadvantage of increased pressure loss.

Furthermore, the presence of the nozzle at the end has the effect of forming a spray stream in which the components are dispersed as fine particles, particularly in the evaporation operation of a heated fluid containing a hardly volatile component.

The effects of the present invention will be illustrated below by giving examples.

Seed - JLJ 915A schedule 203 (inner diameter 18.7+++m)
40A scheduler 40 in a 5US304 tube
5 TPG jackets were attached, and five unit double-tube heat exchangers with flanges on both ends, each 3000 mm in length and 1000 mm in length, were connected using vents, etc., as shown in Figure 1. The evaporator was designed as a evaporator.
Water is supplied as the heated fluid and the pressure is 6Kc to the jacket.
Tested through +/cmz steam.

The state of the fluid coming out of the evaporator is determined by the flow rate of the supplied fluid (
(unit view/min, the same applies to the following examples) is shown below.

0.45 Completely superheated steam with no pulsation 0.75 Completely superheated steam with pulsation 1,05 Same as above 1.50 Completely superheated steam with a little pulsation 2.25 Steam with a little pulsation that does not produce water droplets The pressure of the steam passed through the jacket containing 16Ko/Cl11
However, the results were as shown below.

0.45 Completely superheated steam with no pulsations 1.05 Completely superheated steam with large pulsations 1,50
Same as above 2.25 Steam with large pulsation and containing some water droplets 1-32''1 A nozzle with an inner diameter of 6 ml was added to the end of the evaporator used in the comparative example, and a pressure of 16 and 9/cm'L was added to the end of the evaporator used in the comparative example. When the same operation was performed using steam, the following results were obtained.

0.45 Completely superheated steam with no pulsations 1.05 Completely superheated steam with large pulsations 1,50
When evaporation was carried out in the same manner by inserting an orifice with an inner diameter of 11 mm at a point 1000 mm from the end toward the supply side instead of the two nozzles at the top and bottom, the same results as above were obtained.

Maru i91 A nozzle with an inner diameter of 6IllIIl is installed at the end of the evaporator,
Furthermore, an orifice with an inner diameter of 111IIIn was inserted 1000mm closer to the supply side, and the pressure was also 16Kg/cm.
Water was evaporated using steam.

The amount of water supplied and the state of the obtained fluid were as follows.

0.45 Completely superheated steam without pulsation 1, 05 Same as above 1, 50 Same As above, in place of the upper and lower 2 orifices, a line mixer ("High Mixer" made by Toshi, nominal diameter 15 mm, 16 elements)
When a similar test was carried out by inserting the same, complete superheated steam without pulsation was obtained, as in the above case.

A nozzle with an inner diameter of 6III11 was added to the end of the evaporator, an orifice with an inner diameter of 81 am was inserted 1000 mm closer to the supply side, and an orifice with an inner diameter 12 mm was inserted 4000 mm closer to the supply side to perform evaporation. .

The results are as follows: 0.45 Completely superheated steam without pulsation 1, 05 Same as above 1, 50 Same as above 2, 25 Same as above Pulsation was completely prevented over a wide flow rate range and perfectly superheated steam was obtained. It was done. This is thought to be due to the improvement in the heat transfer coefficient due to the insertion of the orifice.

Using the same equipment as in Example 1, but using a line mixer instead of an orifice, the pressure was set to 6! l
A liquid containing 10% of fish extract is heated through 10 m of steam and heated to a temperature of 0.45 to 1.2 m.
b tc supplied at a rate of 5 fl/min.

The spray stream coming out of the nozzle was extremely fine and stable, and by collecting it in a cyclone and cooling it, a product useful as a jelly-like seasoning was obtained.

Also, when a mixture of 10% starch added to the above stock solution is supplied, a fine and stable spray stream can be similarly obtained, and this spray stream can be further brought into contact with hot air at 200°C to dry the soubre. When the drying process was carried out, a dry product in the form of a dark brown fine powder was stably obtained within the same supply liquid amount range as above. It is useful as a seasoning.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the overall configuration of an example of the evaporator of the present invention. FIG. 2 is a diagram corresponding to a portion of FIG. 1 showing the main parts of another example of the evaporator of the present invention. 1... Double pipe heat exchanger 2... Heated object flow path 3... Nozzle 4... Orifice 5... Line mixer

Claims (4)

[Claims] (1) In evaporation using a double-pipe heat exchanger, by providing a disturbance effect to the flow of the heated fluid in the middle of the flow path and passing the heated fluid through a nozzle at the end of the flow path. , an evaporation method characterized by performing evaporation while preventing pulsation. (2) The evaporation method according to claim 1, wherein a mixture of an easily volatile component and a hardly volatile component is heated to form a spray stream in which the latter is present in the form of a mist in the vapor of the former. (3) A double-tube heat exchanger type evaporator, characterized in that at least one resistor is inserted in the middle of the flow path of the fluid to be heated, and a nozzle is provided at the end. (4) The evaporator according to claim 3, wherein the resistor is selected from an orifice dew, a line mixer, a baffle plate, a filler, and a nozzle.