CN109000488B

CN109000488B - Dot matrix heat exchanger

Info

Publication number: CN109000488B
Application number: CN201810642640.0A
Authority: CN
Inventors: 栗永利; 杨春笋; 张辉; 吕良忠; 张锴; 杜小泽; 杨勇平
Original assignee: North China Electric Power University
Current assignee: North China Electric Power University
Priority date: 2017-09-14
Filing date: 2018-06-21
Publication date: 2024-05-28
Anticipated expiration: 2038-06-21
Also published as: CN107702566A; CN109000488A; CN208688296U

Abstract

The invention relates to a heat exchange structure, and provides a dot matrix heat exchanger, which comprises: the device comprises a bottom plate (3), wherein a lattice type split body (4) is arranged on the bottom plate (3); a first fluid channel for transporting a high viscosity fluid, the first fluid channel comprising a first fluid inlet (11) and a first fluid outlet (12); a second fluid passage for conveying a low viscosity fluid, the second fluid passage being arranged up and down with respect to the first fluid passage in a staggered direction; wherein the lattice-type split fluid (4) alternately divides and intersects the inflowing first fluid from the first fluid inlet (11) to the first fluid outlet (12). The lattice heat exchanger provided by the invention has the advantages that the heating and the reaction of the fluid are more uniform.

Description

Dot matrix heat exchanger

Technical Field

The present invention relates to a heat exchange structure, and more particularly, to a lattice heat exchanger.

Background

The microchannel heat exchanger has high specific surface area, large heat exchange area and high heat exchange efficiency, and can achieve the heat exchange effect in a short time. However, the pressure loss is large when the fluid flows through due to the small size of the micro channel. When the viscosity of the fluid is so great, the pressure drop can be so great that the fluid machine cannot provide enough pressure for the fluid to flow, i.e. the microchannel heat exchanger fails. In order to achieve the purpose of heating high-viscosity fluid, the high-viscosity fluid is usually directly heated in a kettle-type reactor, namely, the purpose of continuous production cannot be achieved.

To achieve continuous production, conventional tube-in-tube or plate heat exchangers are typically used to heat the high viscosity fluid. The clearance in the sleeve is in millimeter level. The heat exchange area is smaller and the heating time is long. Moreover, the internal thermal conductivity of the resin is relatively slow. In the double-pipe heat exchanger, the heating surface is concentrated on the pipe wall, and the resin is heated unevenly because of slow heat conduction in the resin. In order to meet the needs of the emulsification process, in the case of heating the resin using a common plate heat exchanger made of a metal material with good heat conductivity, if heating is performed using oil, the wall surface can rapidly reach the temperature of the heated oil, and if the designed residence time is short, it is likely that the internal fluid has not yet started to rise in temperature due to the low thermal conductivity of the fluid. If the residence time is designed to be long, the waste of energy and heat exchanger pipes can be caused. In addition, for industrial convenience, resistance heating is more convenient than oil heating. However, the resistance heating easily causes too large temperature gradient in the fluid, so that the fluid near the pipe wall is locally heated too much and the temperature rises too fast, thereby carbonizing part of the resin in the heating process and damaging the chemical production.

Disclosure of Invention

The invention aims to solve the problem of intensified heat exchange of high-viscosity resin in a micro-channel.

The invention provides a lattice heat exchanger, comprising: the base plate is provided with a lattice type split body; a first fluid channel for conveying a high viscosity fluid, the first fluid channel comprising a first fluid inlet and a first fluid outlet; a second fluid passage for conveying a low viscosity fluid, the second fluid passage being arranged up and down with respect to the first fluid passage in a staggered direction; the dot matrix type fluid distribution is arranged from the first fluid inlet to the first fluid outlet, and the inflowing first fluid is alternately divided and converged.

In another embodiment, the present invention provides a lattice heat exchanger comprising: the base plate is provided with a lattice type split body; a first fluid channel for conveying a high viscosity fluid, the first fluid channel comprising a first fluid inlet and a first fluid outlet; a heat transfer rod in contact with the bottom plate, and arranged up and down with the first fluid passage, with a direction staggered; the dot matrix type fluid distribution is arranged from the first fluid inlet to the first fluid outlet, and the inflowing first fluid is alternately divided and converged.

The technical scheme of the invention is that the micro-channel reactant utilizes the lattice column on the plate heat exchanger to split the reaction fluid in the reaction process, and the column on the heat exchanger can heat the fluid in the reaction process. For example, the lattice is distributed in N number and uniformly distributed on the microchannel interface, the second row is N+1 (N+2, N+3, N+4, N+5 …, etc.), the front and back rows form fork type distribution, the front lattice column is positioned behind the gap between the front row and the back row after the fluid is split and heat exchanged, the fluid is split again and mixed after the columns, and thus the fluid mixing is more uniform. Although the latter lattice columns are denser and denser, at the same time, the viscosity of the fluid is reduced with the increase of temperature due to the fact that the fluid is continuously heated in the flowing process, and the resistance is smaller, and the two results are offset.

Drawings

Fig. 1 is a cross-sectional view of one embodiment of the heat exchanger of the present invention.

Fig. 2 is a diagram showing the simulation effect on the vertical section after heat exchange of the prior art heat exchanger.

Fig. 3 shows a cross-sectional view of the heat exchanger shown in fig. 1 in a side view.

Fig. 4 is a graph showing a simulation effect on a horizontal cross section of a heat exchanger of the prior art after heat exchange.

Fig. 5 is a graph showing a simulation effect on a horizontal cross section of a heat exchanger of the prior art after heat exchange.

Fig. 6 is a graph showing the simulation effect on a horizontal section after heat exchange of the heat exchanger of the present invention.

Fig. 7 is a graph showing the simulation effect on a horizontal section after heat exchange of the heat exchanger of the present invention.

Fig. 8 is a cross-sectional view of another embodiment of the emulsifying device of the present invention.

Reference numerals

A first fluid inlet 11, a first fluid outlet 12; a first fluid channel 13; a second fluid inlet 21; a second fluid outlet 22; a second fluid passage 23; a bottom plate 3; and a split body 4.

Detailed Description

Embodiments of the present invention will now be described with reference to the drawings, wherein like elements are designated by like reference numerals. The following embodiments and technical features in the embodiments may be combined with each other without collision.

Because of the low coefficient of thermal conductivity of the high viscosity resin, it is easy to locally exchange heat too high and the center temperature too low during the heat exchange process. If heated with conventional microchannels, the boundary layer may be too resistive. Therefore, the invention provides a dot matrix heat exchanger, which strengthens heat exchange by a dot matrix arrangement method.

Fig. 1 shows a schematic structural diagram of an embodiment of the heat exchanger according to the invention, which is a view of the heat exchanger from a top view, with the upper plate of the heat exchanger removed and only the bottom plate 3 being left. As shown in fig. 1, the heat exchanger of the present invention has two fluid passages, a first passage from left to right and a second passage from top to bottom (or alternatively from bottom to top) in the drawing, respectively. The bottom plate 3 at the intersection of the two fluid channels has a matrix of flow splitters 4. The first fluid channel has a first fluid inlet 11 and a first fluid outlet 12 and the second fluid channel has a second fluid inlet 21 and a second fluid outlet 22. The first channel is used for transporting a fluid of high viscosity, such as oil, resin, etc. The second channel is used for delivering a fluid of low viscosity, such as water. The first fluid channel and the second fluid channel are divided into upper and lower layers to cross each other, but the fluids in the two layers are not mixed.

The arrangement of the matrix-type shunt 4 is as follows: on the bottom plate 3, from the first fluid inlet 11 to the first fluid outlet 12, the density is gradually increased (and thus the size of the split fluid 4 is gradually reduced) in rows, the front-rear distance of each row is gradually reduced, and the front-rear rows are staggered.

The dividing body is for example a cylinder or other shape. Taking a cylinder as an example, the cylinder has a dimension diameter of, for example, 200 microns and a height of 1 millimeter. As shown in FIG. 1, from left to right, the first row of cylinders is 800 microns apart, the second row 600 microns … up to the last row 200 microns apart, and then the spacing between cylinders in the same row is progressively smaller compared to the previous row. So that the fluid, after passing through the cylinder, splits into multiple strands, which then merge and then continue to split. By doing so, the fluids are continuously mixed by continuously dividing and continuously converging. Moreover, the cylinder has a disturbance effect, so that the aim of reducing the temperature gradient is fulfilled, and the cylinder is more obvious particularly under the condition of high flow rate.

While the cylinders are used for heating the fluid, the heat of the cylinders being conducted from the upper and bottom plates 3 of the heat exchanger. The upper and lower heat exchanging surfaces (upper plate and bottom plate) may be integral with the cylinder. Further, since the material to be manufactured is a material (for example, copper) having excellent heat conduction, the thermal energy of the upper plate and the bottom plate 3 is rapidly conducted to the cylinder, and it can be considered that the cylinder is at the same temperature as the upper plate and the bottom plate 3.

The pressure drop is also relatively small because the cylinder spacing begins to be relatively large, with a corresponding low temperature and high viscosity. The back row cylinders have smaller spacing, and the corresponding temperature is high, the viscosity is small, and therefore the pressure drop is smaller. Also, during the flow, the pressure drop at each heat exchange section (each row of cylinders) is relatively uniform. So that the low flow resistance is ensured while the heat exchange is enhanced.

Fig. 2 shows a side view of the heat exchanger shown in fig. 1 (seen on the side of the first fluid inlet 11). On both sides are a second fluid inlet 21 and a second fluid outlet 22. A multi-layered bottom plate 3 may be provided so that a multi-layered lattice fluid distribution body 4 may be provided, and thus, the first fluid passages 13 and the second fluid passages 23 are formed to be staggered up and down.

Fig. 3 shows the heat exchanger of fig. 1 in a sectional view at a side view (seen from the side of the second fluid inlet 21). On both sides are a first fluid inlet 11 and a first fluid outlet 12. The first fluid channel 13 and the second fluid channel 23 are staggered up and down. The second fluid channel 23 is used for transporting water and is therefore not split.

The invention carries out simulation experiments, and the simulation example: the microchannel is 1mm high, 1 cm wide and about 4mm long. The inner dimension is as follows: the first row, 10 columns of 200 microns diameter, spaced 800 microns apart, are arranged across a width of 1 cm, the second row is spaced 600 microns apart, the third row is spaced 400 microns apart, and the fourth row is spaced 200 microns apart. The row spacing was 1 mm. When the resin flow rate is 1.4e-3kg/s, the resin flows through 4 rows of lattice channels. The heating surface may be supplied by fluid or by resistive heating.

If the same size channel of the column is not set up. The skin layer reaches the wall temperature quickly, and the resin near the wall becomes a heat insulating tape which prevents the internal resin from heating because of low internal heat conduction. The internal temperature is low. The temperature gradient is evident, see fig. 4-5. Particularly, in the case of resistance heating, local heating is easy to be excessively high, and the overall temperature is low, so that local carbonization is even caused. The tube wall temperature was 140 degrees celsius. When the lattice is arranged in the furnace, the lattice ensures that the temperature distribution is uniform. See fig. 6-7.

Figures 4-5 show the simulated effect of prior art heat exchangers with temperature display of the resin interface of the resin when heated. The simulation conditions were: the flow rate is 1.4e-3kg/s, the inlet temperature is 20 ℃, and the wall temperature is 140 ℃. In fig. 4 to 5, Y represents a distance from the resin inlet. It can be seen that even up to 3.3 mm, the resin was heated unevenly on the inside and carbonized on the outside due to the excessive temperature, but the inside temperature did not meet the requirements.

FIGS. 6-7 show the simulated effect of the heat exchanger of the present invention, with a flow of 1.4e-3kg/s, an inlet temperature of 20 degrees Celsius and a wall temperature of 140 degrees Celsius. Y represents the distance from the resin inlet. It can be seen that at 3.3 mm, the internal temperature of the resin is uniform.

The heat exchanger of the invention adopts a gradual change channel method. At low temperature, the channels are larger and the temperature distribution is uneven. Then, the temperature gradually increases, and through the stand, a plurality of divisions are carried out, and the mixing is strengthened, so that the temperature distribution is uniform.

The invention utilizes the dot matrix heat exchanger and the micro-reactor to increase the reaction effect of the high-viscosity fluid. It should be noted that the dot matrix channels and the dot matrix arrangement dimensions described herein are in a specific form. The dimensions may vary for different fluids.

Fig. 8 shows a structural view of another embodiment of the lattice heat exchanger of the present invention. Similar to the embodiment shown in fig. 1, the first fluid channel has a first fluid inlet 11 and a first fluid outlet 12. The first fluid passage is for delivering a high viscosity fluid, such as oil. The difference from that shown in fig. 1 is that the heating means is replaced by a resistive rod, which is heated by an external circuit. Each heating layer is composed of two cylindrical heat conducting resistance rods which are respectively inserted into the two reserved holes. Heat is conducted from the cylindrical wall to the plate of each heated layer. The electric resistance heating device has the advantages of convenience in resistance heating, small occupied area, quick heating, large heatable range and difficult control of the temperature of the heat transfer wall surface.

The above embodiments are only preferred embodiments of the present invention, and it is intended that the common variations and substitutions made by those skilled in the art within the scope of the technical solution of the present invention are included in the scope of the present invention.

Claims

1. A lattice heat exchanger, comprising:

The bottom plate (3) is provided with a dot matrix type split fluid (4), front and rear rows of split fluid are distributed in a fork type manner, the split fluid in the rear row is denser than the split fluid in the front row in the flow direction of the fluid from the first fluid inlet (11) to the first fluid outlet (12), and the distance between the front row and the rear row of split fluid is shorter along with the direction of the fluid;

a first fluid channel for transporting a high viscosity fluid, the first fluid channel comprising a first fluid inlet (11) and a first fluid outlet (12);

a second fluid passage for conveying a low viscosity fluid, the second fluid passage being arranged up and down with respect to the first fluid passage in a staggered direction;

Wherein the lattice-type split fluid (4) alternately divides and intersects the inflowing first fluid from the first fluid inlet (11) to the first fluid outlet (12).

2. The heat exchanger according to claim 1, wherein the heat exchanger is arranged in a heat exchanger tube,

The lattice heat exchanger comprises a plurality of groups of heat exchange units, wherein each group of heat exchange units comprises a bottom plate (3), the first fluid channel and the second fluid channel.

3. A lattice heat exchanger, comprising:

A cylindrical heat-conducting resistive rod in contact with the bottom plate (3), and arranged up and down with the first fluid channel, with a direction staggered;

4. A heat exchanger according to claim 3 wherein,

The lattice heat exchanger comprises a plurality of groups of heat exchange units, wherein each group of heat exchange units comprises a bottom plate (3) and the first fluid channel.