CN101532792A - Heat exchanger for heating temperature and residence time sensitive products - Google Patents

Abstract

The invention relates to heat exchanger for heating temperature and residence time senxitive products, which being able to cool or heat temperature sensitive and/or polymerisible products in mild and rapid mode.

Description

Be used to heat heat exchanger to the product of temperature and residence time sensitive

Technical field

The present invention relates to a kind of heat exchanger that is used for thermally sensitive and/or polymerisable product.

Background technology

Many as can be known different heat exchanger embodiments from document.For example form is that the heat exchanger of plate type heat exchanger or micro heat exchanger helps the brief stay time.Yet these heat exchangers have shortcoming, and promptly owing to narrow flow gap, they only are applicable to low-viscosity product.For the product of high viscosity more, falling through the pressure of heat exchanger may be very high.For the product that tends to polymerization, monomer or also contain the polymerization syrup of monomer for example has the danger of polymerization in heat exchanger at work or stopping period monomer.It is very complicated removing polymerization syrup from plate type heat exchanger or micro heat exchanger, or even impossible.For the high viscosity substance of many handkerchiefs (Pas) particularly be higher than the high pressures of 10 crust, because the power of manufacture method and appearance can not provide plate type heat exchanger.

US-PS 1.961.907 has described a kind of tube bundle heat exchanger, and it has the body that squeezes of spiral band groove in pipe.Because flowing, helical form reached especially effectively heat transmission.But because the medium for the treatment of temperature adjustment can produce the extra pressure loss and the extra time of staying squeezing inner the flowing of pipe, this may be harmful to product.Fu Za design also can cause cost height, detachability difference and empty operational difficulties in addition.

DE-G 87 12 815 (VIA method and technology association) has described a kind of tube bundle heat exchanger that is used for compressed-air drier.For saving material, the body self that squeezes in the ingress pipe also is made of the pipe in the approaching side sealing.Squeeze pipe and can have the surface of being with groove.Yet this is not that the structure that designs for temperature sensitive product has the very big volume of being filled by product, does not have the bottom of very little support (Hold-up) and squeezes rod not sealing in the bottom owing to have to use.In addition, it is non-removable squeezing pipe, and this thermally sensitive condensate is very big shortcoming.

DE-G 89 03 349 (VIA method and technology association) has described a kind of tube bundle heat exchanger that is used in particular for compressed-air drier.In order to make heat transfer medium flow through device as far as possible equably, in device, be provided with a porous plate, it guarantees flowing uniformly towards pipe.Yet the heat transfer of gentleness there is no need in this tube bundle heat exchanger, so to the not special requirement of the cross section that squeezes rod and excellent or flat without any need for having squeezing of minimum support.In addition, it is non-detachable squeezing rod.

Even also having the heat exchanger that very low pressure falls under the situation of high-viscosity products for example is the tube bank type usually.In this embodiment, product flows through a plurality of pipes that be arranged in parallel.Yet its shortcoming is that this tube bundle heat exchanger has little ratio heat-transfer surface usually.This than heat-transfer surface at this ratio definition, filling product in the described pipe by volume in heat exchange surface and the pipe.Because heat exchange surface is very little, therefore need the big heat exchanger that supports in the big pipe that has usually.The time of staying therefore can be very high in this tube bundle heat exchanger.

Summary of the invention

At the prior art of having discussed, present purpose is a kind of heat exchanger of exploitation, and it makes in heat exchanger time of staying of product to be heated or cooling short as far as possible.Heat exchanger should further design like this, and promptly low viscous product and high viscosity product can both be heated or cooled.

Embodiment by heat exchanger tries hard to realize:

● pressure fall very little in, also can realize the very short time of staying;

● clean easily;

● make easily;

● sealing easily;

● can be used for very wide temperature, pressure and viscosity scope; With

● can handle the temperature contrast between product chamber and heating or cooling chamber well.

This purpose realizes that by such tube bundle heat exchanger it has the specially designed rod that squeezes in the pipe of filling product.These squeeze rod design like this, and promptly they account for and surpass volume in 40% the pipe, preferably account for to surpass volume in 50% the pipe, more especially preferably account for to surpass volume in 60% the pipe.For the volume of being filled by product in will installing keeps less, advantageously, one or morely squeeze in the heat exchanger cover that body is arranged on device or use at least one flat.

Description of drawings

The longitudinal sectional view of Fig. 1 heat exchanger;

The transverse sectional view of Fig. 2 heat exchanger;

The transverse sectional view of Fig. 3 Fig. 4;

Fig. 4 squeezes the view of rod;

The transverse sectional view of Fig. 5 Fig. 6;

Fig. 6 squeezes the view of rod; And

Fig. 7 and 8 illustrates the special setting of squeezing body.

The specific embodiment

1. the design of tube bundle heat exchanger

Describe

Tube bundle heat exchanger comprises shell (4) and tube bank, and this tube bank is to be made of the one or more pipes product percolation, substantially parallel setting of temperature adjustment of being treated.Pipe can be mutually alignedly, biasing ground or be provided with on concentric hole circle.Pipe preferred minimum and essentially identical interval, thereby realize the very little volume of being filled (6) by product.Especially preferably pipe is arranged on the concentric circles, so that realize evenly flowing and make the dead band in the bottom section very little towards pipe.

Product flows through described pipe and is heated or cooled by tube shell.The shell body of heating or cooling medium (5) these pipes of percolation.Heating or cooling medium (5) can flow to pipe across, oppositely or in the same way with product stream.Temperature adjustment is preferably carried out with the intersection reverse flow basically, because little thermograde is enough between temperature control medium (5) and product chamber (6).In order to empty work simply, product preferably flows through heat exchanger from top to bottom.In order to realize the ventilation of heating or cooling medium (5) simply, temperature control medium (5) preferably flows through heat exchanger from the bottom up.

At least one end of tube bank surrounds by a bottom, and product enters by this bottom or comes out.This bottom can be designed to the heat exchanger cover (2) of thin-walled, or is designed to heavy wall but compact flat (17).This bottom preferably has a device flange, so this bottom can flange be connected on the critical piece of heat exchanger or disassembles once more.This bottom preferably can have the sleeve pipe that is positioned on the axis, and product can enter or comes out by this sleeve pipe.May also be considered that, near axis a plurality of sleeve pipes are set, product can come out by these sleeve pipes.This bottom is preferably designed to available temperature control medium and heats or cool off.But also can consider electrical heating.

May also be considered that heat exchanger is directly connected on other device, therefore can omit relative bottom on this side.

Be compensate for dilatation, compensator is installed in shell body when needed, so that the different heat expansion between compensation tube bank and the shell body.

Advantage

Pressure in the Tube Sheet of Heat Exchanger falls by selecting suitable pipe controllable diameter system to be used for the product of viscosity higher.

2. squeeze the design of rod

Describe

Conduct heat in order to reduce the volume of product (6) in Tube Sheet of Heat Exchanger and to improve, squeeze rod (7,10,12,15) and be imported in the pipe.Squeezing rod (7,10,12,15) can partly put in the heat exchanger cover (2).Squeeze rod (7,10,12,15) design like this, promptly they have squeezed and have surpassed 40% volume in the Tube Sheet of Heat Exchanger.Preferably, the empty volume above 60% squeezes by squeezing rod (7,10,12,15) in the pipe.Preferably be less than 95% volume and squeezed, so that obtain the Compact Design of heat exchanger and less pressure falls.The exterior contour that squeezes rod (7,10,12,15) is designed so that the axis that squeezes rod (7,10,12,15) is centered at tube hub, so that avoid the dead band and obtain flowing uniformly on the cross section of Tube Sheet of Heat Exchanger.Product stream flows in the gap (11) between the inwall that squeezes rod (7,10,12,15) and Tube Sheet of Heat Exchanger.

Be centrally located in the pipe with predetermined gap in order to squeeze rod (7,10,12,15), squeeze rod (7,10,12,15) and can followingly design, for example:

The pipe of both sides sealing, the hollow body or the solid (15) of sealing, its cross section (14,16) is out of shape at least two subregions (14,16) along its axis, to be centered between two parties in the pipe (9) (seeing Fig. 2 and 5-6);

● the pipe of both sides sealing, the hollow body or the solid (12) of sealing, it has the element (13) that externally is provided with at least on two axial locations, to be centered between two parties in the pipe (seeing Fig. 3-4);

● along the plate of tubular axis line biasing, it has the characteristic of squeezing volume.

Therefore squeeze rod (7,10,12,15) and preferably be inserted in the pipe (9), they can take out again once more for cleaning and testing goal in case of necessity.Squeezing rod (7,10,12,15) also can be made up of a plurality of single barred bodies that link to each other successively.What also can consider is, uses the hollow rod that squeezes, and is filled with in it to improve the medium that heat is transmitted.For example can comprise water, it evaporates at thermal region, condense at cool region, so heat just transmits in the axial direction.What also can consider is that the heat transfer medium that squeezes pipe by means of flowing through additionally transmits heat.Another possibility is, uses the electrically heated rod that squeezes, thereby can further improve than heat-transfer surface, also can further reduce the time of staying.What equally also can consider is to use the above-mentioned combination of squeezing rod.

Squeeze rod and preferably produce a narrow cross section at the heating part of pipe, the cross section that an expansion can be set in entrance area is to reduce the pressure loss in pipe territory, base area.

Advantage

Reduced the support of product in pipeline (6) by squeezing rod (7,10,12,15), increased simultaneously and compared heat-transfer surface.Via the pressure that has the tube bundle heat exchanger that squeezes rod (7,10,12,15) fall with in micro heat exchanger and plate type heat exchanger, compare with same thermal power and pipe quantity little.Under the situation of micro heat exchanger and plate type heat exchanger, can only be by in these heat exchanger types, obviously increasing the quantity of pipe, pressure falls just can drop to the level with the tube bundle heat exchanger that squeezes rod.The cleaning difficulty that very little pipe diameter and relatively large pipe quantity can be aggravated heat exchanger greatly.

Have squeeze the rod tube bundle heat exchanger in the time of staying certainly than same diameter with squeeze the rod tube bundle heat exchanger in not shorter.Have only for have significantly than minor diameter but the obvious longer blank pipe of its length, its time of staying just can be adjusted to and the par that has the tube bundle heat exchanger that squeezes rod.

3. squeeze body in the heat exchanger cover

Describe

In order to be minimized in the support of heat exchanger cover (2) lining, to squeeze body (3) and be installed in the heat exchanger cover (2).Heat exchanger cover (2) equally also can be heated or cooled.For realizing centering, the heat exchanger cover can have for example sheet metal or pin on the outside.In order to make Tube Sheet of Heat Exchanger scribble liquid equably, preferably conical towards a side of Tube Sheet of Heat Exchanger, see Fig. 7.

Advantage

The time of staying in heat exchanger cover (2) is shorter, so the thermic load of product is lower.

4. flat

The flat (see figure 8) of (low volume head) that the zone that is used for product inlet (1) and products export (8) also can be designed to have recess.The size of this recess can be set like this, make that under the full-power situation time of staying of product in flat is between 0.5 second to 20 seconds, preferably between 1.5 seconds to 15 seconds, or be under the situation of sub-load between 1 second to 40 seconds, preferably between 1.5 seconds to 30 seconds.This recess can be for example by boring or mill and make.Flat recess can be designed to conical.

5. operational factor

Describe

Running temperature T=-20 ℃ to+400 ℃.

Pressure P in the product chamber of pipe (6) and cover (2)=-0.95barg extremely+100barg.

Pressure in the space of heat transfer medium (5) can be at P=-0.95barg between+the 50barg.The temperature of heat transfer medium (5) can be T=-20 ℃ to+400 ℃.

Heat transfer medium (5) can be liquid or vapor form input.The suitable viscosity of describing by the present invention that heats or cool off of heat exchanger is the product of η=0.1mPas to 500Pas.The time of staying of product in heat exchanger can be 1 second to 300 seconds.

Advantage

This heat exchanger allows regulating in temperature, pressure, the range of viscosities widely.

At the conventional heat exchanger of prior art with have between the heat exchanger of annular gap and compare:

Following form has been summed up mass balance and energy balance and flowing in pipe and annular gap and has been reached the result of heat transfer calculations.The calculating of the pressure loss is based on and is used for by the pipe of laminar flow (breathe out root equiulbrium flow Hagen-Poiselle flow) or is used for by the analytical plan of the pulse conservation equation of the annular gap of laminar flow.Heat transfer calculations is based on semiempirical nusselt number (Nusselt number) relation of the laminar flow that is used for waterpower or not moulding of heat.Except as otherwise noted, mass flow is 1.000kg/h, and the time of staying in pipe is 60 seconds, and it is 100K that the temperature of medium to be heated rises, and the logarithm temperature difference between heat transfer medium (5) and medium to be heated is 30K.Last two numerical value can be by being combined to form quotient 3.33.In addition, use thermal conductivity, the 1000kg/m of 0.15W/mK ³Density, the specific heat capacity of 2200J/kgK and the constant dynamic viscosity crop material numerical value of 1Pas, that is to say and adopt newton's medium.Prerequisite is in addition, and hot transfer impedance on heat-transfer area and the conduction resistance by tube wall are negligible.

	Pipe example A	Pipe example B	Pipe example C	Pipe example D	Pipe example E	Pipe example F	Pipe example G	Pipe example H	Annular gap example I
										The time of staying/second	60	25	60	580	60	5	60	60	60
The merchant of the temperature rising and the logarithm temperature difference	3.33	3.33	12.7	3.33	0.80	3.33	23.7	3.33	3.33
										Pressure falls/clings to	4.4	4.4	4.4	4.4	4.4	4.4	4.4	0.069	4.4
Pipe quantity	170	408	2120	18	6	2041	6610	1360	40
										Length of tube/rice	4.7	2.0	2.0	45.5	14.6	0.4	1.4	0.6	3.0
Pipe diameter/millimeter	5.2	3.3	2.2	16	16	1.5	1.5	5.2	24/20

Example A illustrates, and requires very narrow and very long pipe under the situation of conventional tube bundle heat exchanger, so that reach given condition.Yet they manufacture very difficult, and may clean hardly.

Example B and C illustrate, and shorter pipe may make the time of staying shorter (example B) or change heat condition (example C).Simultaneously, however the pipe diameter no longer reduce, therefore and pipe quantity increases significantly, can not regard the replacement scheme of example A as.

Example D and E illustrate, and more the bassoon diameter can be by the longer time of staying (example D) or higher wall temperature (because the bigger logarithm temperature difference; Example E) realizes.Yet because the advantage of the better cleaning brought of major diameter is by the length of tube effacement of phenomenal growth, it makes makes more difficultly, owing to having increased the time of staying and wall temperature product quality is degenerated simultaneously.In addition, in building, so the space requirement of Chang device in building also is a problem.

Example F and G show, and littler pipe diameter is because the heat condition (example G) of the shorter time of staying (example F) or variation causes the quantity of pipe very big.Because the device of tube bank must be exposed under high pressure and the high temperature, considers high pressure and high temperature, can't make the exquisiteness pipe of so big quantity.

The length of tube of can not ignore also makes the inside of device clean.

Example H shows, and the pressure that reduces falls because pipe quantity increases and contraction in length can not cause less pipe diameter.Simultaneously because a large amount of light wall pipes with the length of can not ignore, so cleanablity and manufacturability also almost are impossible.

By contrasting of design of the present invention (example I) and conventional tube bundle heat exchanger (example A-H):

Example I illustrates the design that has the heat exchanger that squeezes rod according to of the present invention by demonstration mode.Consider that the time of staying, heat condition and pressure fall, it is compared with the example of the tube bundle heat exchanger (example A-H) of routine has very big pipe diameter, and it has guaranteed good cleanablity.In addition, compare with E with example A, D, length of tube keeps within limits, and therefore has good manufacturability and cleanablity, only requires little space simultaneously.And, to compare with F-H with example A-C, the quantity of pipe seldom consequently can realize simple and economical production.

Can particularly advantageously be applied in the synthetic aspect of polymer by tube bundle heat exchanger of the present invention, because when carrying out effective geothermal transfer, the polymerization that the chien shih product bears less thermic load and avoids not expecting during brief stay.

Computational methods:

Thermal balance from tube wall:

$\frac{L}{\mathrm{\τ}}\·\frac{\mathrm{\π}}{4}(d_a^2-d_i^2)\·{\mathrm{\ρc}}_p\mathrm{\Δ}{T}_S=\frac{N_{\mathrm{\μm}}\·\mathrm{\λ}}{d_h}\·\mathrm{\π}{d}_{a}L\·\mathrm{\Δ}{T}_{\lg }$ Set out

Predesignating three geometric parameters (overall diameter d in gap _a, the interior diameter d in gap _i, length of tube L) in two situation under, just can calculate the 3rd geometric parameter.

Here, L is the length of pipe or annular gap, and r is the time of staying, d _aBe the overall diameter or the pipe diameter in gap, d _iIt is the inside diameter (pipe: d of annular gap _i=0), p is a density, c _pBe specific heat capacity, Δ T _SThe temperature that is syrup raises d _hBe hydraulic diameter, λ is a pyroconductivity, Δ T _1gIt is the logarithm temperature difference between heat medium (5) and syrup.

Considering under the situation of waterpower and startup heat according to Baehr/Stefan (W

Rme-und Stoff ü bertragung, Springer-Verlag Berlin, 1994, the 381-382 pages or leaves) calculate the mean value Nu of the nusselt number (Nusselt number) that is used for pipe _mCalculate by following relational expression:

${\mathrm{N\&mu;}}_{m,\mathrm{Rohr}}=\frac{1}{\tanh (2.432\&CenterDot;{\mathrm{<figure-callout\; id="1"\; label="Pr"\; filenames="A200910007748E00131.png,A200910007748E00161.png"\; state="\{\{state\}\}">Pr</figure-callout>}}^{1/3}){\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="A200910007748E00131.png,A200910007748E00161.png"\; state="\{\{state\}\}">X</figure-callout>}}^{1/6}}\&CenterDot;(\frac{3.657}{\tanh (2.264\&CenterDot;{\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="A200910007748E00131.png,A200910007748E00161.png"\; state="\{\{state\}\}">X</figure-callout>}}^{1/3}+1.7\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="A200910007748E00131.png,A200910007748E00161.png"\; state="\{\{state\}\}">X</figure-callout>}}^{2/3})}+\frac{0.0499}{X}\tanh \left(X\right))$

Here, P _rBe Prandtl number, X is no dimensions length:

$X=\frac{L}{d_h\mathrm{Pe}}=\frac{\mathrm{\&tau;\&lambda;}}{{\mathrm{<figure-callout\; id="2"\; label="d\; h"\; filenames="A200910007748E00131.png,A200910007748E00161.png"\; state="\{\{state\}\}">d</figure-callout>}}_h^{}\mathrm{\&rho;}{c}_p}$

By K=d _i/ d _a, the following mean value that is applicable to the nusselt number of the annular gap that calculating is externally heated:

Nμ _m，RS＝3.657+1.2·K ^1/2+(Nμ _m，Rohr-3.657)·(1+0.14·K ^1/3)

According to Martin (W

Rme ü bertrager, Georg ThiemeVerlag Stuttgart,, the 24th page in 1988), the following pressure loss that is applicable in annular gap or the pipe (K=0):

$\mathrm{\&Delta;p}=\frac{32\mathrm{\&mu;}{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A200910007748E00131.png,A200910007748E00161.png"\; state="\{\{state\}\}">L</figure-callout>}}^2}{\mathrm{\&tau;}{d}_a^2}\&CenterDot;\frac{1-{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="A200910007748E00131.png,A200910007748E00161.png"\; state="\{\{state\}\}">K</figure-callout>}}^2}{1-{\mathrm{<figure-callout\; id="4"\; label="K"\; filenames="A200910007748E00131.png,A200910007748E00161.png"\; state="\{\{state\}\}">K</figure-callout>}}^4+\frac{{(1-K^2)}^2}{\ln \left(K\right)}}.$

List of numerals

1. product inlet

2. heat exchanger cover

3. squeeze body

4. heat exchanger shell

5. at Tube Sheet of Heat Exchanger heating and/or cooling medium on every side

6. the product chamber in the Tube Sheet of Heat Exchanger

7. in each pipe of tube bank, squeeze rod

8. products export

9. Tube Sheet of Heat Exchanger (schematically)

10. squeeze rod

11. squeeze the free volume between rod and the Tube Sheet of Heat Exchanger

12. squeeze rod

13. escapement is used for making and squeezes rod and arrange between two parties in Tube Sheet of Heat Exchanger

14. the central area in the subregion of squeezing rod

15. squeeze rod

16. the central area in the subregion of squeezing rod

Flat 17. (low capacity head)

Claims (10)

1. under the situation of temperature sensitive and/or polymerisable medium, be used for the tube bundle heat exchanger that heat is transmitted, it is characterized in that, one tube bank is arranged on one to have in the housing (4) of one or more products exports (8) and one or more product inlet (1), in each pipe of tube bank, be provided with and squeeze rod (7,10,12,15), and at least one heat exchanger cover of tube bundle heat exchanger is filled with and squeezes body (3), to reduce the volume of being filled by product.

2. according to the described tube bundle heat exchanger of claim 1, it is characterized in that,

For cleaning purpose, squeeze rod (7,10,12,15) and constitute removable.

3. according to the described tube bundle heat exchanger of claim 1, it is characterized in that,

Squeeze the cross section that rod (7,10,12,15) has automatic centering.

4. according to the described tube bundle heat exchanger of claim 1, it is characterized in that,

Squeeze rod (7,10,12,15) and fill pipe volume greater than 40%.

5. according to the described tube bundle heat exchanger of claim 1, it is characterized in that,

Squeeze rod (7,10,12,15) and fill pipe volume greater than 50%.

6. according to the described tube bundle heat exchanger of claim 1, it is characterized in that,

Squeeze rod (7,10,12,15) and fill pipe volume greater than 60%.

7. according to the described tube bundle heat exchanger of claim 1, it is characterized in that,

The pipe volume that squeezes rod (7,10,12,15) filling the highest 95%.

8. by the application of the described tube bundle heat exchanger of above arbitrary claim when synthetic polymer.

9. under the situation of temperature sensitive and/or polymerisable medium, be used for the tube bundle heat exchanger that heat is transmitted, it is characterized in that, one tube bank is arranged in the columniform basically housing (4), this housing has one or more products exports (8) and one or more product inlet (1), in the pipe of tube bank, be provided with and squeeze rod (7,10,12,15), and at least one bottom of tube bundle heat exchanger constitutes flat (17), to reduce the volume of being filled by product.

10. according to the described tube bundle heat exchanger that under the situation of temperature sensitive and/or polymerisable medium, is used for the heat transmission of claim 9, it is characterized in that the time of staying of product in the recess of flat (17) is between 0.5 second and 40 seconds.

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