CN108489307B - Plate-fin heat exchanger - Google Patents

Abstract

A plate-fin heat exchanger, comprising a heat exchange core formed by stacking at least two fluid channels, the plane where the spacer plate between two adjacent fluid channels is located forms an angle with the horizontal plane, and the fluid channel extends from one end to the horizontal plane. The other end is sequentially provided with a medium inlet, heat exchange fins and a medium outlet, wherein the medium outlet includes a first liquid phase medium outlet and a vapor phase medium outlet, the first liquid phase medium outlet is arranged at the lower part of the fluid channel, and the vapor phase medium outlet is arranged in the upper part of the fluid channel. In the above-mentioned plate-fin heat exchanger, the gravitational potential energy difference is generated due to the height difference after the medium enters, and the liquid phase entrained by the vapor-liquid two-phase medium, or the liquid phase generated by the condensation of the vapor-phase medium during the heat exchange process, tends to be due to the effect of gravity. Settling in the direction of gravity, the vapor-phase medium and liquid-phase medium flow out of the plate-fin heat exchanger respectively. The above-mentioned plate-fin heat exchanger not only has the function of heat exchange, but also has the function of gas-liquid separation, and has a simple structure, which saves the cost and reduces the space occupation of the structure.

Description

Plate Fin Heat Exchanger

technical field

The invention relates to the technical field of heat exchangers, in particular to a plate-fin heat exchanger.

Background technique

Existing chemical and thermal energy fields are widely involved in the flow of media (vapor phase, liquid phase or vapor-liquid two-phase). When a single-phase (vapor or liquid) medium undergoes heat exchange or pressure change, a vapor-liquid two-phase flow may be formed. Due to the significant differences in physical properties such as the density and viscosity of the vapor phase and the liquid phase, and the chemical/thermal energy process has Different characteristics and functions require phase separation of the vapor-liquid two-phase flow, and output vapor-phase and liquid-phase media respectively.

As a special example, in the field of natural gas liquefaction, when the natural gas feed gas is preliminarily cooled to -50°C, the heavy hydrocarbon components contained in it will condense into a liquid phase and methane gas to form a vapor-liquid two-phase flow. If the vapor-liquid separation is not performed, the vapor-liquid two-phase flow will continue to be cooled to a low temperature, which will cause part of the liquid phase to solidify and block the heat exchanger channel and cause the system to shut down. Therefore, it is necessary to separate the heavy hydrocarbon components in the liquid phase from the methane gas by vapor-liquid separation, and the separated methane gas enters the subsequent process, while the heavy hydrocarbon components in the liquid phase are taken out separately for processing.

Traditional plate-fin heat exchangers usually use a vapor-liquid separator downstream of the heat exchanger for vapor-liquid separation after the medium heat exchange. Both the heat exchanger and the vapor-liquid separator are pressure vessels, and All take up space. Therefore, there are problems of high cost, complexity, and large space occupation.

SUMMARY OF THE INVENTION

In view of this, it is necessary to provide a plate-fin heat exchanger with low cost, simple structure, and small space occupation, which can perform gas-liquid separation.

A plate-fin heat exchanger, comprising a heat exchange core formed by stacking at least two fluid channels, the plane where the spacer plate between two adjacent fluid channels is located forms an angle with a horizontal plane, and the fluid channels A medium inlet, a heat exchange fin and a medium outlet are arranged in sequence from one end to the other end, wherein the medium outlet includes a first liquid phase medium outlet and a vapor phase medium outlet, and the first liquid phase medium outlet is arranged in the fluid channel The lower part of the said vapor-phase medium outlet is arranged in the upper part of the said fluid channel.

In one embodiment, the included angle formed between the plane where the spacer plate is located between two adjacent fluid channels and the horizontal plane is a right angle.

In one embodiment, a first guide fin is further provided between the medium inlet and the heat exchange fin, and the medium entering the plate-fin heat exchanger from the medium inlet passes through the first guide fin. The guide action of the guide fins flows into the channels between the heat exchange fins.

In one embodiment, second guide fins are provided between the outlet of the vapor-phase medium and the heat exchange fins, and the vapor-phase medium in the channels between the heat exchange fins passes through the second guide fins The diversion effect of the gas phase medium flows out of the plate-fin heat exchanger from the outlet of the vapor phase medium, and a third diversion fin is also provided between the outlet of the first liquid phase medium and the heat exchange fins, and the heat exchange fins The liquid-phase medium in the channel between them flows out of the plate-fin heat exchanger from the first liquid-phase medium outlet through the guiding effect of the third guiding fins.

In one embodiment, the heat exchange fins are serrated fins, perforated fins, or corrugated fins with cutouts and perforations.

In one embodiment, the heat exchange fins are inclined downward in a direction close to the horizontal plane to form an included angle of less than 90 degrees with the horizontal plane.

In one embodiment, the heat exchange fins include a first section of heat exchange fins close to the medium inlet, a second section of heat exchange fins close to the first liquid phase medium outlet, and a second section of heat exchange fins close to the vapor phase The third section of heat exchange fins at the medium outlet, the first section of heat exchange fins are inclined downward in the direction close to the horizontal plane to form an included angle of less than 90 degrees with the horizontal plane, and the second section of heat exchange fins are parallel to the horizontal plane. Set on a horizontal plane, the third-stage heat exchange fins are inclined upward obliquely in a direction away from the horizontal plane to form an included angle of less than 90 degrees with the horizontal plane.

In one embodiment, at least one of the vapor-phase medium outlet and the first liquid-phase medium outlet is provided with a throttle regulating valve for controlling the vapor-phase medium outlet and the first liquid-phase medium outlet The distribution ratio of the medium flow.

In one embodiment, the vapor-phase medium outlet is provided at the end of one end of the fluid channel, and the first liquid-phase medium outlet is provided at the bottom of one end of the fluid channel.

In one embodiment, the bottom of the plate-fin heat exchanger is further provided with a second liquid-phase medium outlet.

A plate-fin heat exchanger, comprising a heat exchange core formed by stacking at least two fluid channels, one end of the fluid channel is provided with a medium inlet and a liquid-phase medium outlet on both sides, and the middle part of the fluid channel is provided with a medium inlet and a liquid medium outlet respectively. Heat exchange fins are provided, the heat exchange fins are arranged perpendicular to the horizontal plane, the other end of the fluid channel is provided with a vapor-phase medium outlet, and a first guide is provided between the medium inlet and the heat exchange fins. Flow fins, second guide fins are arranged between the vapor phase medium outlet and the heat exchange fins, and third flow guide fins are arranged between the liquid medium outlet and the heat exchange fins piece.

In the above plate-fin heat exchanger, after the medium enters the plate-fin heat exchanger from the medium inlet, the medium in the fluid channel produces a difference in gravitational potential energy due to the height difference, and the liquid phase entrained by the vapor-liquid two-phase medium, or the vapor-phase medium is The liquid phase produced by condensation during the heat exchange process tends to settle in the direction of gravity due to the action of gravity and accumulate at the bottom of the fluid channel, while the vapor-phase medium flows above the liquid-phase medium, so that the vapor-phase medium and the liquid-phase medium flow out of the plate respectively. Fin heat exchanger. Therefore, the above-mentioned plate-fin heat exchanger not only has the function of heat exchange, but also has the function of gas-liquid separation. The above-mentioned plate-fin heat exchanger has a simple structure, saves the cost, and reduces the space occupation of the structure.

Description of drawings

1 is a schematic structural diagram of a plate-fin heat exchanger according to an embodiment;

2 is a schematic structural diagram of a plate-fin heat exchanger according to another embodiment;

3 is a schematic structural diagram of a plate-fin heat exchanger according to another embodiment;

4 is a schematic structural diagram of a plate-fin heat exchanger according to another embodiment;

5 is a schematic structural diagram of a plate-fin heat exchanger according to another embodiment;

FIG. 6 is a schematic structural diagram of a plate-fin heat exchanger according to another embodiment.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

As shown in FIG. 1 , a plate-fin heat exchanger according to an embodiment includes a heat exchange core formed by stacking at least two fluid channels 100 , and the plane where the spacer plate between two adjacent fluid channels 100 is located and the horizontal plane are formed. At an included angle, the fluid channel 100 is sequentially provided with a medium inlet 10, heat exchange fins 20 and a medium outlet from one end to the other end, wherein the medium outlet includes a first liquid phase medium outlet 32 and a vapor phase medium outlet 34, the first liquid medium outlet 32 and the vapor phase medium outlet 34. The phase medium outlet 32 is provided in the lower part of the fluid channel 100 , and the vapor phase medium outlet 34 is provided in the upper part of the fluid channel 100 .

The above-mentioned plate-fin heat exchanger, by forming an angle between the plane of the spacer plate between the fluid channels 100 and the horizontal plane, after the medium enters the plate-fin heat exchanger from the medium inlet 10, the medium in the fluid channel 100 due to the height difference The gravitational potential energy difference is generated, and at the same time, according to the structural characteristics of the heat exchange fins 20 in the fluid channel 100, as well as the physical properties and flow parameters of the fluid, the vapor-liquid phase separation velocity V _d of the vapor-liquid two-phase flow is calculated, so that the vapor-liquid separation is performed. The flow velocity of the fluid medium in the fluid channel 100 is V<V _d , the liquid phase entrained by the vapor-liquid two-phase medium, or the liquid phase produced by the condensation of the vapor-phase medium during the heat exchange process tends to settle in the direction of gravity due to the action of gravity, It gathers at the bottom of the fluid channel 100, while the vapor-phase medium flows above the liquid-phase medium, so that the vapor-phase medium and the liquid-phase medium flow out of the plate-fin heat exchanger from the vapor-phase medium outlet 34 and the first liquid-phase medium outlet 32, respectively. . Therefore, the above-mentioned plate-fin heat exchanger not only has the function of heat exchange, but also has the function of gas-liquid separation. It can be seen that the above-mentioned plate-fin heat exchanger has a simple structure, saves the cost, and reduces the space occupation of the structure.

The above-mentioned plate-fin heat exchanger fully utilizes the "cold capture" effect in the process of vapor-liquid separation (the wall of the heat exchanger with a lower temperature than the medium can promote the adsorption and aggregation of the liquid medium on the wall), which can Obtain better vapor-liquid separation effect.

In one embodiment, the included angle formed between the plane of the spacer plate between two adjacent fluid channels 100 and the horizontal plane is a right angle. That is, the partition plates between two adjacent fluid channels 100 are arranged perpendicular to the horizontal plane.

In one embodiment, the heat exchange fins 20 can be zigzag fins, perforated fins with high perforation rate, or corrugated fins with appropriate cuts and perforations, or other new types of fins that are conducive to vapor-liquid phase separation piece. The heat exchange fins 20 are designed with the above-mentioned structure, which is beneficial to the separation of vapor and liquid.

In the above-mentioned plate-fin heat exchanger, the heat exchange fins 20 are in the form of sawtooth fins or other fins that are conducive to cross-flow, and the medium is self-distributed in the fluid channel 100 . Where the fluid channel 100 is not provided with a medium inlet and a medium outlet, a channel seal 40 is provided for sealing the medium in the fluid channel 100 .

Referring to FIG. 2 , in one embodiment, a first guide fin 50 is further provided between the medium inlet 10 and the heat exchange fins 20 of the plate-fin heat exchanger, and enters the plate-fin heat exchange from the medium inlet 10 The fluid in the heat exchanger flows into the channels between the heat exchange fins 20 through the guiding action of the first guiding fins 50 .

A second guide fin 60 is provided between the vapor-phase medium outlet 34 and the heat exchange fin 20 . A third guide fin 70 is further provided between the first liquid phase medium outlet 32 and the heat exchange fin 20 . The vapor-phase medium in the channels between the heat exchange fins 20 flows out of the plate-fin heat exchanger from the vapor-phase medium outlet 34 through the guiding action of the second guide fins 60 . The liquid-phase medium in the channels between the heat exchange fins 20 flows out of the plate-fin heat exchanger from the first liquid-phase medium outlet 32 through the guiding action of the third guiding fins 70 .

Referring to FIG. 3 , in one embodiment, the heat exchange fins 20 of the plate-fin heat exchanger are inclined downward in a direction close to the horizontal plane to form an included angle of less than 90 degrees with the horizontal plane. This arrangement is more conducive to the deposition of the liquid medium to the bottom of the fluid channel 100 .

Referring to FIG. 4 , in one embodiment, the heat exchange fins in the fluid channel 100 are arranged in sections. Specifically, the heat exchange fins include a first section of heat exchange fins 22 close to the medium inlet 10 , a second section of heat exchange fins 24 close to the first liquid phase medium outlet 32 , and a third section close to the vapor phase medium outlet 34 . Heat exchange fins 26 . The first-stage heat exchange fins 22 are inclined downward in a direction close to the horizontal plane to form an included angle of less than 90 degrees with the horizontal plane. The second-stage heat exchange fins 24 are arranged parallel to the horizontal plane. The third-stage heat exchange fins 26 are inclined upwards in a direction away from the horizontal plane to form an included angle of less than 90 degrees with the horizontal plane. The first-stage heat exchange fins 22 are inclined downward in a direction close to the horizontal plane, which is more conducive to the deposition of the liquid medium to the bottom of the fluid channel 100 . The second-stage heat exchange fins 24 are arranged parallel to the horizontal plane, and can guide the liquid-phase medium to smoothly flow to the first liquid-phase medium outlet 32 at the bottom of the fluid channel 100 . The third-stage heat exchange fins 26 are inclined upward in a direction away from the horizontal plane, which is more conducive to reducing the flow resistance of the vapor-phase medium.

In one embodiment, at least one of the vapor-phase medium outlet 34 and the first liquid-phase medium outlet 32 is provided with a throttling valve (not shown) for controlling the vapor-phase medium outlet 34 and the first liquid-phase medium outlet The distribution ratio of the medium flow of 32. That is, a throttling valve may be provided at the vapor-phase medium outlet 34 or the first liquid-phase medium outlet 32 to control the medium distribution ratio between the vapor-phase medium outlet 34 and the first liquid-phase medium outlet 32 . Alternatively, flow control valves are provided at both the vapor-phase medium outlet 34 and the first liquid-phase medium outlet 32 to adjust the flow distribution between the vapor-phase medium outlet 34 and the first liquid-phase medium outlet 32 .

In the embodiment shown in FIG. 1 , the vapor-phase medium outlet 34 is provided at the end of one end of the fluid channel 100 . The first liquid-phase medium outlet 32 is provided at the bottom of one end of the fluid channel 100 to facilitate the outflow of the liquid-phase medium from the fluid channel 100 .

Referring to FIG. 5 , in one embodiment, the bottom of the plate-fin heat exchanger is further provided with a second liquid-phase medium outlet 36 , and the number of the second liquid-phase medium outlet 36 is two. It can be understood that the number of the second liquid-phase medium outlets 36 can be set as required. By arranging a plurality of liquid-phase medium outlets at the bottom of the plate-fin heat exchanger, during the cooling process of the medium, the condensate will continue to be produced, which will settle to the bottom of the fluid channel 100, and will be discharged out of the plate-fin heat exchanger in time through the liquid-phase medium outlets of all levels. Heater.

Referring to FIG. 6 , the plate-fin heat exchanger of another embodiment includes a heat exchange core formed by stacking at least two fluid channels 200 , and a medium inlet 210 and a liquid phase are respectively provided on both sides of one end of the fluid channel 200 . The medium outlet 220, the middle of the fluid channel 200 is provided with heat exchange fins 230, the heat exchange fins 230 are arranged perpendicular to the horizontal plane, the other end of the fluid channel 200 is provided with a vapor phase medium outlet 240, a medium inlet 210 and heat exchange fins 230 A first guide fin 250 is arranged between the two, a second guide fin 270 is arranged between the vapor phase medium outlet 240 and the heat exchange fin 230, and a liquid phase medium outlet 220 and the heat exchange fin 230 are arranged between The third guide fins 260 . Where the fluid channel 200 is not provided with a medium inlet and a medium outlet, a channel seal 280 is provided for sealing the medium in the fluid channel 100 .

In the plate-fin heat exchanger shown in FIG. 6, the main flow direction of the medium in the plate-fin heat exchanger is from bottom to top, and the direction of the heat exchange fins 230 in the plate-fin heat exchanger is also arranged as In the vertical direction, the medium enters the plate-fin heat exchanger from one side of the bottom of the fluid channel 200, the vapor-phase medium flows out from the top of the fluid channel 200, and the liquid-phase medium exits the plate-fin heat exchanger from the other side of the bottom of the fluid channel 200. Heat Exchanger. Therefore, the above-mentioned plate-fin heat exchanger not only has the function of heat exchange, but also has the function of gas-liquid separation. It can be seen that the above-mentioned plate-fin heat exchanger has a simple structure, saves the cost, and can reduce the space occupation of the structure.

The above-mentioned plate-fin heat exchanger can be applied to a natural gas liquefaction process. In the natural gas liquefaction process, the natural gas feed gas contains heavy hydrocarbon components. If it directly enters the low temperature stage, the heavy hydrocarbon components will solidify and block the heat exchanger. Using the above plate-fin heat exchanger, the heavy hydrocarbon gas-liquid separator is no longer required in the natural gas liquefaction cold box, and the condensate generated during the cooling process of the natural gas feed gas is separated from the plate-fin heat exchanger.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can also be made, and these improvements and modifications should also be regarded as It is the protection scope of the present invention.

Claims (4)

1. A plate-fin heat exchanger is characterized by comprising a heat exchange core body formed by stacking at least two fluid channels, wherein the plane of a partition plate between every two adjacent fluid channels forms an included angle with the horizontal plane, a medium inlet, a heat exchange fin and a medium outlet are sequentially arranged in each fluid channel from one end to the other end, each medium outlet comprises a first liquid-phase medium outlet and a vapor-phase medium outlet, the first liquid-phase medium outlet is arranged at the lower part of each fluid channel, and the vapor-phase medium outlet is arranged at the upper part of each fluid channel; a first guide fin is arranged between the medium inlet and the heat exchange fins, and a medium entering the plate-fin heat exchanger from the medium inlet flows into a channel between the heat exchange fins under the guide action of the first guide fin; a second guide fin is arranged between the vapor-phase medium outlet and the heat exchange fins, vapor-phase medium in a channel between the heat exchange fins flows out of the plate-fin heat exchanger from the vapor-phase medium outlet under the guide action of the second guide fin, a third guide fin is also arranged between the first liquid-phase medium outlet and the heat exchange fins, and liquid-phase medium in a channel between the heat exchange fins flows out of the plate-fin heat exchanger from the first liquid-phase medium outlet under the guide action of the third guide fin; the heat exchange fins comprise a first section of heat exchange fin close to the medium inlet, a second section of heat exchange fin close to the first liquid-phase medium outlet and a third section of heat exchange fin close to the vapor-phase medium outlet, the first section of heat exchange fin slants obliquely downwards in a direction close to the horizontal plane to form an included angle smaller than 90 degrees with the horizontal plane, the second section of heat exchange fin is arranged in parallel with the horizontal plane, and the third section of heat exchange fin slants obliquely upwards in a direction far away from the horizontal plane to form an included angle smaller than 90 degrees with the horizontal plane.

2. The plate fin heat exchanger of claim 1, wherein the heat exchange fins are saw-tooth fins, perforated fins, or corrugated fins with slits and perforations.

3. The plate fin heat exchanger of claim 1, wherein at least one of the outlet for the vapor phase medium and the outlet for the first liquid phase medium is provided with a throttle regulating valve for controlling the division ratio of the medium flow rates of the outlet for the vapor phase medium and the outlet for the first liquid phase medium.

4. The plate fin heat exchanger of claim 1, wherein the bottom of the plate fin heat exchanger is further provided with a second liquid phase medium outlet.

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