CN112082409B

CN112082409B - Shell-and-tube heat exchanger with regularly changed valve opening

Info

Publication number: CN112082409B
Application number: CN201911126180.7A
Authority: CN
Inventors: 衣秋杰; 王逸隆; 郭春声; 冷学历
Original assignee: Beijing Ruichen Hangyu Energy Technology Co ltd
Current assignee: Beijing Ruichen Hangyu Energy Technology Co ltd
Priority date: 2019-11-18
Filing date: 2019-11-18
Publication date: 2022-05-17
Anticipated expiration: 2039-11-18
Also published as: CN112082409A

Abstract

The invention provides a shell-and-tube heat exchanger with a valve opening degree changing regularly, wherein a heat exchange part comprises a right tube box, a left tube box and heat exchange tubes, a first heat exchange tube penetrates through the inside of the left tube box, and a second heat exchange tube penetrates through the right tube box; the inlets of the first heat exchange tube and the second heat exchange tube are respectively provided with a first valve and a second valve which are in data connection with a controller, and the controller controls the opening size of the first valve and the opening size of the second valve to periodically change along with the change of time. According to the invention, through controlling the change of the opening degree of the first valve and the second valve, the fluid can be frequently evaporated and expanded in the elastic tube bundle, and the stability of the elastic tube bundle is damaged due to the continuous periodic change of the expansion and the flowing direction of the steam, so that the vibration of the elastic tube bundle is continuously driven, and the heat exchange efficiency and the descaling operation can be further realized.

Description

Shell-and-tube heat exchanger with regularly changed valve opening

Technical Field

The invention relates to a shell-and-tube heat exchanger, in particular to a shell-and-tube heat exchanger with a valve controlled to open and close to induce vibration.

Background

The invention relates to a project which is developed by cooperating with Qingdao science and technology university and relates to descaling of a heat exchanger, and the project is a novel invention which is applied to a shell-and-tube heat exchanger on the basis of the development of the Qingdao science and technology university (application number 2019101874848).

The shell-and-tube heat exchanger is widely applied to industries such as chemical industry, petroleum industry, refrigeration industry, nuclear energy industry and power industry, and due to the worldwide energy crisis, the demand of the heat exchanger in industrial production is more and more, and the quality requirement of the heat exchanger is higher and more. In recent decades, although compact heat exchangers (plate type, plate fin type, pressure welded plate type, etc.), heat pipe type heat exchangers, direct contact type heat exchangers, etc. have been rapidly developed, because the shell and tube type heat exchangers have high reliability and wide adaptability, they still occupy the domination of yield and usage, and according to relevant statistics, the usage of the shell and tube type heat exchangers in the current industrial devices still accounts for about 70% of the usage of all heat exchangers.

After the shell-and-tube heat exchanger is scaled, the heat exchanger is cleaned by adopting conventional modes of steam cleaning, back flushing and the like, and the production practice proves that the effect is not good. The end socket of the heat exchanger can only be disassembled, and a physical cleaning mode is adopted, but the mode is adopted for cleaning, so that the operation is complex, the consumed time is long, the investment of manpower and material resources is large, and great difficulty is brought to continuous industrial production.

The mode of passively strengthening heat exchange is to strictly prevent the fluid vibration induction in the heat exchanger from being changed into effective utilization of vibration, so that the convective heat transfer coefficient of the transmission element at low flow speed is greatly improved, dirt on the surface of the heat transfer element is restrained by vibration, the thermal resistance of the dirt is reduced, and the composite strengthened heat transfer is realized.

In application, it is found that continuous heating can cause the internal fluid to form stability, i.e. the fluid does not flow or has little fluidity, or the flow is stable, so that the vibration performance of the heat exchange tube is greatly weakened, thereby affecting the descaling of the heat exchange tube and the heating efficiency. There is therefore a need for improvements to the above-described heat exchangers.

The heat exchanger generally exchanges heat by two fluids, but the heat exchange of three fluids is rarely researched, the three-fluid heat exchange is researched, a novel shell-and-tube heat exchanger for inducing vibration and three fluids is developed,

disclosure of Invention

The invention provides an induced vibration shell-and-tube heat exchanger with a novel structure, aiming at the defects of the shell-and-tube heat exchanger in the prior art. The shell-and-tube heat exchanger can realize heat exchange of three fluids, and the periodic frequent vibration of the heat exchange tubes improves the heating efficiency, thereby realizing good descaling and heating effects.

In order to achieve the purpose, the invention adopts the following technical scheme:

a shell-and-tube heat exchanger with a valve opening rule changing comprises a shell and a heat exchange component; the heat exchange component comprises a right tube box, a left tube box and a heat exchange tube, the heat exchange tube is communicated with the right tube box and the left tube box, the left tube box and/or the right tube box are/is filled with phase-change fluid, and the phase-change fluid is subjected to closed circulation in the right tube box, the left tube box and the heat exchange tube; the heat exchanger is characterized by comprising a first heat exchange tube and a second heat exchange tube, wherein the first heat exchange tube penetrates through the left tube box; the shell side fluid is a cold source, the fluid in the first heat exchange tube and the second heat exchange tube is a heat source, the inlets of the first heat exchange tube and the second heat exchange tube are respectively provided with a first valve and a second valve, the first valve and the second valve are in data connection with a controller, the controller controls the opening degree of the first valve and the opening degree of the second valve, and the control law is as follows:

one period is T, and in the half period of 0-T/2, when T is 0, the first valve is closed, and the opening of the second valve is maximum; v when the flow rate of the fluid is at the maximum opening of the first valve and the second valve; adjusting the flow rates of the first fluid and the second fluid for n times;

then every T/2n time, the valve opening controlled by the first valve is increased, so that the flow rate of the first fluid per unit time is increased by V/n until the first valve opening is maximum at the T/2 time, and simultaneously the valve opening controlled by the second valve is reduced, so that the flow rate of the second fluid per unit time is reduced by V/n until the second valve is closed at the T/2 time;

and in the half period of T/2-T, every T/2n, the opening degree of the second valve is increased, so that the flow rate of the second fluid per unit time is increased by V/n until the period T is the maximum, and simultaneously the opening degree of the first valve is reduced, so that the flow rate of the first fluid per unit time is reduced by V/n until the T/2 time when the second valve is closed.

Preferably, the number of the heat exchange tubes is one or more, each heat exchange tube comprises a plurality of circular arc-shaped tube bundles, the central lines of the circular arc-shaped tube bundles are circular arcs with the lower tube boxes as concentric circles, and the end parts of the adjacent tube bundles are communicated, so that the end parts of the tube bundles form free ends of the tube bundles; and exchanging heat of the first shell pass fluid through the heat exchange of the first fluid and the second fluid, thereby realizing three-fluid heat exchange.

Preferably, the period is 50 to 300 minutes. Preferably, the number of the heat exchange tubes is one or more, each heat exchange tube comprises a plurality of circular arc-shaped tube bundles, the central lines of the circular arc-shaped tube bundles are circular arcs with the lower tube boxes as concentric circles, and the end parts of the adjacent tube bundles are communicated, so that the end parts of the tube bundles form free ends of the tube bundles; and exchanging heat of the first shell pass fluid through the heat exchange of the first fluid and the second fluid, thereby realizing three-fluid heat exchange.

Preferably, the maximum opening of the first valve and the second valve are the same.

Preferably, the shell is circular in cross section, the heat exchange components are multiple, one of the heat exchange components is arranged in the center of the shell and becomes a central heat exchange component, the other heat exchange components are distributed around the center of the shell and become peripheral heat exchange components, and the heat exchange power of the single peripheral heat exchange component is smaller than that of the central heat exchange component.

Preferably, the pipe diameter of the right pipe box is equal to that of the left pipe box.

Preferably, a return pipe is provided between the right and left tank.

Preferably, the right tube box and the left tube box are arranged along the horizontal direction, the heat exchange tubes are arranged in a plurality along the flowing direction of the fluid in the shell pass, and the tube diameter of the heat exchange tube bundle is continuously increased along the flowing direction of the fluid in the shell pass.

Preferably, the radius of the inner wall of the shell is R, the center of the central heat exchange component is arranged at the center of the circular cross section of the shell, the distance from the center of the right tube box of the peripheral heat exchange component to the center of the circular cross section of the shell is S, the centers of the right tube boxes of the adjacent peripheral heat exchange components are respectively connected with the center of the circular cross section, an included angle formed by the two connecting lines is a, the unit time flow rate of the first fluid of the peripheral heat exchange component is V2, the inlet temperature is T2, the specific heat is C2, the unit time flow rate of the first fluid of a single central heat exchange component is V1, the inlet temperature is T1, and the specific heat is C1, so that the following requirements are met:

[V2*C2*(T2-T_{standard of merit})]/[V1*C1*(T1-T_{Standard of merit})]A-b Ln (R/S); ln is a logarithmic function; t is_{Standard of merit}The target temperature of the shell-side fluid after heat exchange is set according to the requirement;

a, b are coefficients, wherein 2.0869< a <2.0875,0.6833< b < 0.6837;

preferably, 1.35< R/S < 2.1;

preferably, 1.55<[V2*C2*(T2-T_{Standard of merit})]/[V1*C1*(T1-T_{Standard of merit})]<1.9; wherein the concentration is 35 °<A<80°。

The invention has the following advantages:

1. according to the invention, through controlling the intermittent opening and closing of the first valve and the second valve, on one hand, continuous heat exchange is realized for the shell process flow, and meanwhile, the elastic heat exchange tube can periodically and frequently vibrate, so that good descaling and heat exchange effects are realized.

2. The invention designs a novel heat exchanger with three fluids, which can further improve the heat exchange effect and meet the heat exchange requirements of the three fluids.

3. The invention can continuously exchange heat in the shell process flow by controlling the intermittent flow of the first fluid and the second fluid, and can also make the elastic heat exchange tube vibrate periodically and frequently, thereby realizing good descaling and heat exchange effects.

4. The invention controls the first valve and the second valve to periodically and continuously increase the opening of the heating valve and reduce the opening of the valves, so that the phase-change fluid can be in a changing state with continuous volume after being heated, and further the free end of the heat exchange tube is fully induced to vibrate, thereby strengthening heat transfer.

5. The invention designs that the flow directions of the first fluid and the second fluid are opposite, and further promotes the flow of the phase-change fluid, thereby enhancing the heat transfer.

6. The invention designs a layout of a heat exchange component with a novel structure in a shell, optimizes the optimal relation between the parameters of the heat exchange tube and the flow, specific heat and the like of the fluid through a large number of experiments and numerical simulation, and creatively integrates the flow, the specific heat, the temperature and the target temperature of the heat exchange fluid into the size design of the heat exchanger relative to the previous design, thereby further improving the heat exchange efficiency.

7. Through the flowing direction of fluid in the shell, the reasonable change of the internal diameter and the interval of the tube bundle of the heat exchange tube improves the heat exchange efficiency.

Description of the drawings:

fig. 1 is a schematic structural view of a heat exchanger according to the present invention.

FIG. 2 is a schematic sectional view of a heat exchange member according to the present invention.

Fig. 3 is a top view of a heat exchange member.

Fig. 4 is a schematic diagram of a preferred structure of the heat exchanger.

Fig. 5 is another preferred schematic construction of the heat exchanger.

Fig. 6 is a schematic layout of heat exchange components arranged in a circular shell.

Fig. 7 is a schematic view of the structure of a heat exchange tube.

In the figure: 1. heat exchange tube, 2, right tube box, 3, free end, 4, free end, 5, shell pass inlet connecting tube, 6, shell pass outlet connecting tube, 7, free end, 8, left tube box, 9, connecting point, 10, heat exchange component, 11, shell, 12 tube bundle, 131 first heat exchange tube, 132 second heat exchange tube, front tube plate 14, support 15, support 16, rear tube plate 17, first valve 18, second valve 19,

inlet collecting tube

20, 22, 23,

outlet collecting tube

21, 24, 25

Detailed Description

A shell-and-tube heat exchanger, as shown in fig. 1, the shell-and-tube heat exchanger includes a shell 11, a heat exchange component 10, a shell-side inlet connection pipe 5 and a shell-side outlet connection pipe 6; the heat exchange component 10 is arranged in the shell 11 and fixedly connected to the front tube plate 14 and the rear tube plate 17; the shell side inlet connecting pipe 5 and the shell side outlet connecting pipe 6 are both arranged on the shell 11; fluid enters from a shell side inlet connecting pipe 5, exchanges heat through a heat exchange part and exits from a shell side outlet connecting pipe 6.

Fig. 2 shows a schematic sectional view of a heat exchange part 10 (as viewed from the left side of fig. 1), and as shown in fig. 2, the heat exchange part 10 includes a right tube box 2, a left tube box 8 and a heat exchange tube 1, the heat exchange tube 1 is communicated with the right tube box 2 and the left tube box 8, the left tube box 8 and/or the right tube box 2 is filled with a phase change fluid, and the phase change fluid is in closed circulation in the right tube box 2, the left tube box 8 and the heat exchange tube 1.

The ends of the two ends of the right and left tube boxes are disposed in the openings of the front and

rear tube plates

14, 17 for fixation, as shown in fig. 1.

Preferably, the right and

left headers

2 and 8 extend in the longitudinal direction of the shell side. The shell side preferably extends in the horizontal direction.

As shown in fig. 2, the heat exchanger includes a first heat exchanging pipe 131 and a second heat exchanging pipe 132, the first heat exchanging pipe 131 is disposed through the left channel box 8, and the second heat exchanging pipe 132 is disposed through the right channel box 2; the heat exchange tubes 1 are one or more, each heat exchange tube 1 comprises a plurality of circular arc-shaped tube bundles 12, the central lines of the circular arc-shaped tube bundles 12 are circular arcs taking the axis of the right tube box 2 as a concentric circle, the end parts of the adjacent tube bundles 12 are communicated, and fluid forms serial flow between the right tube box 2 and the left tube box 8, so that the end parts of the tube bundles form tube bundle free ends 3 and 4; the fluid is a phase change fluid, preferably a vapor-liquid phase change liquid. The first and second

heat exchange pipes

131 and 132 flow through a first fluid and a second fluid, respectively. The heat exchange of the three fluids can be carried out among the first fluid, the second fluid and the shell side fluid. For example, the heat exchange process is as follows:

the first fluid is a heat source, the second fluid and the shell pass fluid are cold sources, the phase change fluid in the heat exchange component is subjected to phase change through heat exchange of the first fluid, so that the shell pass fluid is radiated outwards through the tube bundle 12, meanwhile, the vapor phase fluid enters the right tube box 2 to exchange heat with the second fluid, and the condensed fluid after heat exchange returns to the left tube box through the return tube, so that three-fluid heat exchange is realized.

Preferably, the second fluid is a heat source, the first fluid and the shell-side fluid are cold sources, the phase-change fluid in the heat exchange component is subjected to phase change through heat exchange of the second fluid, so that the shell-side fluid is radiated outwards through the tube bundle 12, meanwhile, the vapor-phase fluid enters the left tube box 8 to exchange heat with the first fluid, and the condensed fluid after heat exchange returns to the right tube box through the return tube, so that three-fluid heat exchange is realized.

Preferably, the shell-side fluid is a heat source, the first fluid and the second fluid are cold sources, and the heat exchange of the shell-side fluid enables the fluid in the heat exchange component to absorb heat and exchange heat with the first fluid and the second fluid, so that three-fluid heat exchange is realized.

Preferably, the first fluid is a cold source, the second fluid and the shell-side fluid are heat sources, and heat exchange is realized through the second fluid and the shell-side fluid, so that three-fluid heat exchange is realized.

Preferably, the second fluid is a cold source, the first fluid and the shell-side fluid are heat sources, and the heat exchange between the first fluid and the shell-side fluid is carried out to exchange heat with the second fluid, so that three-fluid heat exchange is realized.

Preferably, the shell-side fluid is a cold source, the first fluid and the second fluid are heat sources, and the heat exchange of the first fluid and the second fluid is carried out to exchange heat with the third shell-side fluid, so that the three-fluid heat exchange is realized.

Preferably, the first heat exchange tube and the second heat exchange tube have the same inner diameter.

The following description focuses on the case where the shell-side fluid is the heat sink and the first and second fluids are the heat sources.

Preferably, as shown in fig. 4 and 5, the first valve 18 and the second valve 19 are arranged at the inlets of the first heat exchange tube 131 and the second heat exchange tube 132, the first valve 18 and the second valve 19 are in data connection with a controller, and the controller controls the opening and closing and the opening of the first valve and the second valve for controlling the flow of the heat exchange fluid entering the first heat exchange tube and the second heat exchange tube.

Research and practice find that the heat exchange of the heat source with continuous power stability can lead to the fluid forming stability of the internal heat exchange component, namely the fluid does not flow or has little fluidity, or the flow is stable, so that the vibration performance of the heat exchange tube 1 is greatly weakened, and the descaling of the heat exchange tube 1 and the heat exchange efficiency are affected. There is therefore a need for improvements to the heat exchangers described above as follows.

Preferably, the controller controls the flow rate of the heat exchange fluid of the first heat exchange pipe and the second heat exchange pipe to be periodically changed along with the change of time.

Preferably, the controller controls the first valve 18 and the second valve 19 to open and close, so as to control the first fluid and the second fluid to exchange heat periodically and alternately along with the change of time.

Preferably, during one period time T, the controller controls the opening and closing rules of the first valve 18 and the second valve 19 as follows:

in a half period of 0-T/2, the first valve 18 is opened to the maximum, and the second valve 19 is closed, namely the flow of the first fluid is maximum, and the flow of the second fluid is 0;

in the half period of T/2-T, the first valve 18 is closed, the second valve 19 is opened to the maximum, i.e., the flow rate of the second fluid is maximized, and the flow rate of the first fluid is 0.

Most preferably, the maximum opening of the first valve and the second valve are the same.

As another preferable mode, in one cycle time T, the flow rate per unit time of the first fluid is V1, the flow rate per unit time of the second fluid is V2, and the change rule of V1 and V2 is as follows:

in a half period of 0-T/2, V1 is n and V2 is 0, that is, the flow rate of the first fluid is kept constant and the flow rate of the second fluid is 0;

in the half period of T/2-T, V1 is 0 and V2 is n. I.e. the first flow is 0, no heat exchange takes place and the second flow remains constant.

Wherein n is a constant number in m³/s。

Preferably, T is 50 to 80 minutes.

Through the heat exchange with the time variability, the phase-change fluid can be frequently evaporated and expanded in the elastic tube bundle, the stability of single heat exchange is damaged due to the continuous periodic change of the expansion and the flowing direction of the steam, and the vibration of the elastic tube bundle is continuously driven, so that the heat exchange efficiency and the descaling operation can be further realized.

Compared with the prior application, the heat exchange mode ensures that the heat exchanger carries out heat exchange in the whole period, and can also ensure that the elastic tube bundle frequently vibrates, thereby further realizing the heat exchange efficiency and the descaling operation.

Preferably, the controller controls the opening of the first valve and the second valve to change periodically with time.

Preferably, if a period is T, then in a half period of 0-T/2, when T is 0, the first valve is closed, and the opening of the second valve is maximum; v when the flow rate of the fluid is at the maximum opening of the first valve and the second valve; the flow rates of the first fluid and the second fluid are adjusted in n times.

Then, every T/2n time, the valve opening of the first valve control is increased so that the flow rate per unit time of the first fluid is increased by V/n until the first valve opening is maximized at T/2n time, while the second valve opening is decreased so that the flow rate per unit time of the second fluid is decreased by V/n until the second valve is closed at T/2n time.

As another preferable mode, if the one period is T, then in a half period of 0 to T/2, when T is 0, the flow rate per unit time of the first fluid is 0, and the flow rate per unit time of the second fluid is V; the flow rates of the first fluid and the second fluid are adjusted in n times.

Then every T/2n time, the flow rate of the first fluid per unit time is increased by V/n until the flow rate of the first fluid per unit time becomes V at T/2n time, while the flow rate of the second fluid per unit time is decreased by V/n until the flow rate of the second fluid per unit time becomes 0 at T/2n time.

And in the half period of T/2-T, every T/2n, the flow rate of the second fluid per unit time is increased by V/n until the flow rate of the second fluid per unit time becomes V in the period T, and simultaneously the flow rate of the first fluid per unit time is decreased by V/n until the flow rate of the fluid per unit time in the period T/2 is 0.

The flow rate variation is preferably controlled by the first and second valves.

Through the heat exchange with the time variability, the fluid can be frequently evaporated and expanded in the elastic tube bundle, the stability of single heat exchange is damaged due to the continuous periodic change of the expansion and the flowing direction of the steam, and the vibration of the elastic tube bundle is continuously driven, so that the heat exchange efficiency and the descaling operation can be further realized.

Preferably, the first fluid and the second fluid flow in opposite directions. The first fluid and the second fluid flow gradually from two sides to form good heat exchange, so that the flow of the fluids is further promoted, and the elastic vibration effect is increased. Through the change of the flow rate of the unit time with the time variability, the fluid can be frequently evaporated, expanded and contracted in the elastic tube bundle, so that the vibration of the elastic tube bundle is continuously driven, and the heat exchange efficiency and the descaling operation can be further realized.

Preferably, the controller controls the adjustment of the opening of the first valve and the opening of the second valve, and the adjustment amplitude is different in each time.

Preferably, if a period is T, then in a half period of 0-T/2, when T is 0, the first valve is closed, and the opening of the second valve is maximum; a flow rate per unit time V of the fluid at the maximum opening degree of the first valve and the second valve; the flow rates per unit time of the first fluid and the second fluid are adjusted n times.

Then, the valve opening degree of the first valve control is increased every T/2n, the increasing amplitude of the valve opening degree is gradually increased along with the increasing times until the first valve opening degree is maximum at the T/2 time, meanwhile, the second valve opening degree is reduced, and the reducing amplitude of the second valve opening degree is gradually reduced along with the increasing times until the second valve is closed at the T/2 time.

And in the half period of T/2-T, the opening degree of the second valve is increased every T/2n, the increasing amplitude of the opening degree of the valve is gradually increased along with the increasing times until the opening degree of the second valve is maximum in the period T, the opening degree of the first valve is reduced simultaneously, and the decreasing amplitude of the opening degree of the first valve is gradually reduced along with the increasing times until the second valve is closed at the T/2 time.

The flow rate per unit time is gradually increased and decreased by the first fluid and the second fluid, so that the flow of the fluid is further promoted, and the elastic vibration effect is increased. Through the change of the heat exchange power with the time variability, the fluid can be frequently evaporated, expanded and contracted in the elastic tube bundle, so that the vibration of the elastic tube bundle is continuously driven, and the heat exchange efficiency and the descaling operation can be further realized.

Preferably, the flow rate of the first fluid per unit time is linearly increased in the first half cycle, and the flow rate of the first fluid per unit time is linearly decreased in the second half cycle.

Preferably, the period is 50 to 300 minutes, preferably 50 to 80 minutes; the average flow velocity of the first fluid and the second fluid is 0.5 to 5m/s, preferably 1 to 3 m/s.

Preferably, the average temperature of the first fluid is equal to the average temperature of the second fluid, and the flow rate of the first fluid per unit time is equal to the flow rate of the second fluid per unit time. The average temperature is an average of the fluid inlet temperature and the fluid outlet temperature.

Preferably, the first fluid and the second fluid are the same fluid.

As shown preferably in fig. 4, the first fluid and the second fluid have a common inlet header 20 and outlet header 21. Fluid enters the inlet header, enters the first heat exchange tube and the second heat exchange tube through the inlet header for heat exchange, and then flows out through the outlet header.

As shown preferably in fig. 5, the first and second fluids have respective inlet and

outlet headers

22, 23, 24, 25, respectively. The fluid enters the respective inlet header, then enters the first and second heat exchange tubes through the inlet header for heat exchange, and then exits through the respective outlet header.

Preferably, the bottom parts of the right channel box and the left channel box are provided with return pipes, so that the fluid condensed in the first channel box and the second channel box can flow quickly.

Preferably, the pipe diameter of the right pipe box 2 is equal to that of the left pipe box 8. The pipe diameters of the right pipe box and the left pipe box are equal, so that the fluid can be ensured to be subjected to phase change in the first box body and keep the same transmission speed as the left pipe box.

Preferably, the connection position 9 of the heat exchange tube at the right tube box is lower than the connection position of the left tube box and the heat exchange tube. Thus, steam can rapidly enter the left pipe box upwards.

Preferably, a return line is provided between the right and left headers, optionally at the ends 18-20 of the right and left headers, to ensure that condensed fluid in the left header can enter the first line.

Preferably, along the flowing direction of the shell-side fluid, the tube diameter of the heat exchange tube bundle is increased continuously.

The pipe diameter range through the heat exchange tube increases, can guarantee that shell side fluid outlet position fully carries out the heat transfer, forms the heat transfer effect like the adverse current, further strengthens the heat transfer effect moreover for whole vibration effect is even, and the heat transfer effect increases, further improves heat transfer effect and scale removal effect. Experiments show that better heat exchange effect and descaling effect can be achieved by adopting the structural design.

Preferably, the heat exchange tubes are arranged in a plurality along the flowing direction of fluid in the shell side, and the distance between every two adjacent heat exchange tubes is gradually reduced along the flowing direction of the fluid.

Preferably, the interval between the heat exchange tubes becomes smaller and larger along the height direction of the right header.

The interval amplitude through the heat exchange tube increases, can guarantee that shell side fluid outlet position fully carries out the heat transfer, forms the heat transfer effect like the adverse current, further strengthens the heat transfer effect moreover for the whole vibration effect is even, and the heat transfer effect increases, further improves heat transfer effect and scale removal effect. Experiments show that better heat exchange effect and descaling effect can be achieved by adopting the structural design.

Preferably, as shown in fig. 7, the casing is a casing with a circular cross section, and a plurality of heat exchange components are arranged in the casing.

Preferably, as shown in fig. 7, one of the plurality of heat exchange members disposed in the housing is disposed at the center of the housing (the center of the right tube box is located at the center of the housing) to serve as a central heat exchange member, and the other heat exchange members are distributed around the center of the housing to serve as peripheral heat exchange members. Through the structural design, the fluid in the shell can fully achieve the vibration purpose, and the heat exchange effect is improved.

Preferably, a line connecting center points of the right header of the peripheral heat exchange member forms a regular polygon.

Preferably, the flow rates of the first fluid and the second fluid of the single peripheral heat exchange member per unit time are respectively smaller than those of the first fluid and the second fluid of the central heat exchange member. Through the design, the center reaches higher vibration frequency to form a central vibration source, so that the periphery is influenced, and better heat transfer enhancement and descaling effects are achieved.

Preferably, on the same horizontal heat exchange section, the fluid needs to achieve uniform vibration, and uneven heat exchange distribution is avoided. Therefore, the flow rates of the first fluid and the second fluid in different heat exchange parts are required to be reasonably distributed. Experiments show that the heat exchange power ratio of the central heat exchange component to the peripheral tube bundle heat exchange component is related to two key factors, wherein one of the two key factors is the distance between the peripheral heat exchange component and the center of the shell (namely the distance between the circle center of the peripheral heat exchange component and the circle center of the central heat exchange component) and the diameter of the shell. Therefore, the invention optimizes the optimal proportional distribution of the flow rate per unit time according to a large number of numerical simulations and experiments.

[V2*C2*(T2-T_{standard of merit})]/[V1*C1*(T1-T_{Standard of merit})]A-b Ln (R/S); ln is a logarithmic function; t is_{Standard of merit}The target temperature of the shell-side fluid after heat exchange is generally set according to the requirement.

a, b are coefficients, wherein 2.0869< a <2.0875,0.6833< b < 0.6837;

preferably, 1.35< R/S < 2.1; further preferred is 1.4< R/S < 2.0;

preferably, 1.55<[V2*C2*(T2-T_{Standard of merit})]/[V1*C1*(T1-T_{Standard of merit})]<1.9. Further preferred is 1.6<[V2*C2*(T2-T_{Standard of merit})]/[V1*C1*(T1-T_{Standard of merit})]<1.8；

Wherein 35 ° < a <80 °.

Preferably, the number of the four-side distribution is 4-5.

Compared with the prior design, the invention creatively integrates the flow rate of the heat exchange fluid per unit time, the specific heat, the temperature and the target temperature into the size design of the heat exchanger, so the structural optimization is also a key invention point of the invention.

The flow rate of the second fluid in unit time of the same heat exchange component is the same as that of the first fluid in unit time, and the inlet temperature is the same. The flow rate per unit time is an average flow rate per unit time. Preferably the second fluid and the first fluid are the same fluid.

The first fluid flow rate per unit time of the peripheral heat exchange member was V2, the inlet temperature was T1, and the specific heat was C1, which is an average of the plurality of peripheral heat exchange members.

Preferably, R is 1600-2400 mm, preferably 2000 mm; s is 1150-1700 mm, preferably 1300 mm; the diameter of the heat exchange tube bundle is 12-20 mm, preferably 16 mm; the outermost diameter of the heat exchange tube is preferably 300-560 mm, preferably 400 mm. The pipe diameter of the lower manifold is 100-116 mm, preferably 108 mm, and the length of the upper manifold and the lower manifold is 1.8-2.2 m.

More preferably, a is 2.0872 and b is 0.6835.

Preferably, the box body is of a circular section, and is provided with a plurality of heat exchange components, wherein one heat exchange component is arranged at the center of the circle of the circular section, and the other heat exchange components are distributed around the center of the circle of the circular section. The heat exchange tubes 1 are in one group or multiple groups, each group of heat exchange tubes 1 comprises a plurality of circular arc-shaped tube bundles 12, the central lines of the circular arc-shaped tube bundles 12 are circular arcs of concentric circles, and the end parts of the adjacent tube bundles 12 are communicated, so that the end parts of the heat exchange tubes 1 form tube bundle free ends 3 and 4, such as the free ends 3 and 4 in fig. 2.

Preferably, the heat exchange fluid is a vapor-liquid phase change fluid.

Preferably, the right tube box 2, the left tube box 8 and the heat exchange tube 1 are all of a circular tube structure.

Preferably, the tube bundle of the heat exchange tubes 1 is an elastic tube bundle.

The heat exchange coefficient can be further improved by arranging the tube bundle of the heat exchange tube 1 with an elastic tube bundle.

Preferably, the concentric circles are circles centered on the center of the right header 2. I.e., the tube bundle 12 of heat exchange tubes 1 is arranged around the center line of the right tube box 2.

As shown in fig. 7, the tube bundle 12 is not a complete circle, but rather leaves a mouth, thereby forming the free end of the bundle. The angle of the arc of the mouth part is 65-85 degrees, namely the sum of the included angles b and c in figure 7 is 65-85 degrees.

Preferably, the ends of the tube bundle on the same side are aligned in the same plane, with the extension of the ends (or the plane in which the ends lie) passing through the midline of the right tube box 2.

Preferably, the first end of the inner tube bundle of the heat exchange tube 1 is connected with the right tube box 2, the second end is connected with one end of the adjacent outer tube bundle, one end of the outermost tube bundle of the heat exchange tube 1 is connected with the left tube box 8, and the ends of the adjacent tube bundles are communicated, so that a series structure is formed.

The plane of the first end forms an included angle c of 40-50 degrees with the plane of the central lines of the right tube box 2 and the left tube box 8.

The plane of the second end forms an included angle b of 25-35 degrees with the plane of the center lines of the right tube box 2 and the left tube box 8.

Through the design of the preferable included angle, the vibration of the free end is optimal, and therefore the heat exchange efficiency is optimal.

As shown in fig. 7, the number of tube bundles of heat exchange tube 1 is 4, and tube bundles A, B, C, D are communicated. Of course, the number is not limited to four, and a plurality of the connecting structures are provided as required, and the specific connecting structure is the same as that in fig. 7.

The heat exchange tubes 1 are multiple, the heat exchange tubes 1 are respectively and independently connected with the right tube box 2 and the left tube box 8, and namely the heat exchange tubes 1 are in a parallel structure.

Although the present invention has been described with reference to the preferred embodiments, it is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A shell-and-tube heat exchanger with a valve opening rule changing comprises a shell and a heat exchange component; the heat exchange component comprises a right tube box, a left tube box and a heat exchange tube, the heat exchange tube is communicated with the right tube box and the left tube box, the left tube box and/or the right tube box are/is filled with phase-change fluid, and the phase-change fluid is subjected to closed circulation in the right tube box, the left tube box and the heat exchange tube; the heat exchange tube is characterized in that one or more heat exchange tubes are provided, each heat exchange tube comprises a plurality of arc-shaped tube bundles, the central lines of the arc-shaped tube bundles are arcs with the lower tube boxes as concentric circles, and the end parts of the adjacent tube bundles are communicated, so that the end parts of the tube bundles form free ends of the tube bundles; the heat exchanger comprises a first heat exchange tube and a second heat exchange tube, the first heat exchange tube penetrates through the left tube box, and the second heat exchange tube penetrates through the right tube box; the shell side fluid is a cold source, the fluid in the first heat exchange tube and the second heat exchange tube is a heat source, the inlets of the first heat exchange tube and the second heat exchange tube are respectively provided with a first valve and a second valve, the first valve and the second valve are in data connection with a controller, the controller controls the opening degree of the first valve and the opening degree of the second valve, and the control law is as follows:

one period is T, and in the half period of 0-T/2, when T is 0, the first valve is closed, and the opening of the second valve is maximum; a flow rate per unit time V of the fluid at the maximum opening of the first valve and the second valve; adjusting the flow rates of the first fluid and the second fluid for n times;

2. The heat exchanger of claim 1, wherein the period is 50-300 minutes.