DE102014105779B4 - Heat transfer device and method for operating a heat transfer device - Google Patents

Abstract

Heat transfer device (10), in particular for local or district heat transfer, with at least one steam jet pump (15), which comprises: a propellant connection (14) which can be acted upon by steam via a steam supply line (13) and a suction line (17) with a low-pressure steam source (18) connected suction port (16), a diffuser port (22) and an actuator (44) for influencing the propellant port (14) through flowing steam flow, with at least one plate heat exchanger (24), which: via a primary flow line (23) with the diffuser port (22 ) of the steam jet pump (15) connected to the primary flow connection (25) via a primary return line (27) connected to a Kondensatabführungseinrichtung (K) primary return port (26) via a secondary flow line (34) with a heat consumer (35) connected secondary flow connection (33) andeinen via a secondary return line (36) with the Wärmever connected to the primary supply line (23) to produce a pressure signal (p) characterizing the pressure prevailing in the primary supply line (23) at least one control means (51, 46) connected to the pressure sensing means (47) for receiving the pressure signal (p), at least one drive means (45) connected to the control means (51, 46) for controlling the pressure signal Receive control signal (S) and which is connected to the actuator (44) to adjust the vapor flow based on the control signal (S) such that a limiting pressure (p) in the primary flow line (23) is not exceeded, each steam jet pump ( 15) is associated with a respective control device (51, 46).

Description

The invention relates to a heat transfer device, in particular for local or district heat transfer.

For heat transfer is often used steam, which is normally under a considerable pressure of, for example, more than 10 bar and a high temperature up to 200 ° C and higher may have. Heat consumers are usually heated with hot water of, for example 70 ° C or 90 ° C. To transfer the heat energy contained in the steam to hot water serve as steam / water heat exchanger. Such is from the DE 44 422 22 A1 known. The heat exchanger comprises a battery of vessels, in each of which a steam-flowed coil is arranged, which is externally flowed around by the serving as a heat transfer medium water. The steam-flow coiled tubes have sufficient stability to accommodate the existing pressure and heat differential.

Next discloses the DE 198 00 882 C2 a primary-side steam-heated heat exchanger, which serves on the secondary side for heating water. In the heat exchanger, the steam cools and condenses. The heat exchanger comprises tubes which are closed at the end in openings of an intermediate bottom. But even these are at risk from pressure surges that can occur in the steam condensation. An upstream throttle valve can also be damaged by such pressure peaks. The document deals with the prevention of such pressure peaks.

In addition, plate heat exchangers are in use as heat exchangers. This sees the EP 1 734 311 A1 the combination of a jet pump with a plate heat exchanger before, where used as a primary-side heating medium heated water. The use of water as a primary-side, as well as a secondary-side heating medium avoids excessive pressure and heat differences, which are potentially harmful to the plate heat exchanger.

The DE 31 47 052 A1 discloses an arrangement in which wet steam and condensate from the fed by the jet pump process is mixed by means of a jet pump to a heat consumer supplied steam.

The DE 198 59 364 A1 describes a hot water fed heat recovery system with water jet pumps that feed heat consumers in the form of radiators or boilers.

It is an object of the invention to provide a concept for efficient steam / water heat transfer.

This object is achieved with the heat transfer device according to claim 1 and a method for operating a heat transfer device according to claim 15.

The heat transfer device according to the invention includes a steam jet pump whose diffuser port is connected to the primary flow of the plate heat exchanger. Via a control device, the steam jet pump is controlled so that the primary-side pressure at the plate heat exchanger does not exceed a designated limit pressure. In this way, by combining a steam jet pump with plate heat exchanger, a particularly efficient, space-saving heat transfer system can be created. The steam jet pump can be used to control the energy input into the plate heat exchanger. It may further serve to provide high pressure steam, which may, for example, have more than 10 bar gauge, to a slight overpressure of e.g. to reduce only 0.5 bar. The plate heat exchanger has a particularly small internal volume. The product of heat exchanger volume and the prevailing pressure (pressure liter product) can be kept below 200 barl. Thus, the system is not subject to supervision.

1. a) die Regelung der sekundärseitigen Vorlauftemperatur,
2. b) die Absicherung der Anlage, insbesondere die druckmäßige Absicherung des Plattenwärmetauschers durch Schnellschluss,
3. c) die Druckreduzierung des Hochdruckdampfs von einem für den Plattenwärmetauscher unzulässigen Wert, z.B. 12 bar Überdruck, auf einen Grenzwert, der für den Plattenwärmetauscher zulässig ist und die Anlage als nicht überwachungspflichtig einstuft, wie beispielsweise 0,5 bar Überdruck,
4. d) Ansaugung von Niedertemperaturdampf (Abdampf), beispielsweise aus industriellen Prozessen oder Kondensatsammelgefäßen,
5. e) Ermöglichung des Einsatzes effizienter und platzsparender sowie kostengünstiger Plattenwärmetauscher anstelle voluminöser Rohrbündelwärmetauscher.

At the same time, the jet pump exhaust steam from other processes of energetic use. For this purpose, for example, it can suck in broth steam from various other containers, eg cooking kettles, condensate containers or the like. Because of the safe pressure reduction by the jet pump, a TÜV inspection of the system, in particular the plate heat exchanger can be omitted. In addition, the temperature load of the plate heat exchanger can be significantly reduced by the vapor pressure reduction in the steam jet pump. For example, the primary temperature load can be reduced to less than 110 ° C. The steam jet pump can be assigned several functions at the same time, namely:

1. a) the regulation of the secondary-side flow temperature,
2. b) the protection of the system, in particular the pressurized protection of the plate heat exchanger by means of quick closing,
3. c) the pressure reduction of the high-pressure steam from a value which is not permissible for the plate heat exchanger, for example 12 bar overpressure, to a limit which is permissible for the plate heat exchanger and which classifies the installation as non-monitoring, such as 0.5 bar overpressure,
4. d) aspiration of low-temperature steam (exhaust steam), for example from industrial processes or condensate collection vessels,
5. e) Enabling the use of efficient, space-saving and cost-effective plate heat exchangers instead of voluminous tube bundle heat exchangers.

Through the intake of Brüdendampf can be effected an efficient use of residual heat, which improves the energy efficiency of the system.

The combination of the pressure controlled steam jet pump with the plate heat exchanger represents a significant advance over conventional steam / water heat exchangers. The safe and controlled pressure reduction of the steam protects the plate heat exchanger both from the high pressure present at the steam supply line and from the high level there ensured steam temperature ensured.

The steam jet pump works at least pressure-limiting. It can also work pressure-regulating. It can additionally work temperature-limiting, in particular temperature-regulating, by e.g. the primary flow line and / or the plate heat exchanger are connected to a primary temperature sensor. The primary temperature signal generated by the primary temperature sensor is supplied to the control device, which can then regulate a constant or a desired time course following primary temperature.

It is also possible to additionally or alternatively provide a secondary temperature sensor to detect the temperature at or in the secondary flow and to report it to the control device. This can now control the steam jet pump so that, while maintaining the pressure limits, a constant secondary temperature or a secondary temperature following a desired time course or other specifications is achieved.

Cooled steam and / or condensate or a vapor / condensate mixture can occur in the primary duct of the plate heat exchanger. This steam, the condensate or the mixture of both can be fed to a condensate heat exchanger, which is not necessarily but preferably designed as a plate heat exchanger. On the secondary side, the condensate heat exchanger (for example as a preheater) can be connected to a heat consumer, for example a heater, a hot water circuit, a service water storage or the like.

The presented solution is cascadable. Thus, two or more each consisting of steam jet pump and plate heat exchanger pairs can be arranged parallel to each other to provide in a modular system heat transfer devices with different performance. It is possible to bring the individual steam jet pump plate heat exchanger pairs staggered in succession from zero to full load in order to achieve the widest possible output range. However, it is also possible to operate said steam jet pump plate heat exchanger pairings in parallel at full load or in a same or similar partial load range.

Preferably, the drive device and the actuator of the steam jet pump are designed so that they form a quick-closing device. This has a reaction time which is so low that the formation of pressure above the limit pressure in the primary flow line and the plate heat exchanger is excluded. The quick-closing device may be formed by a spring accumulator which, when e.g. is electrically triggered, brings the actuator in the closed position to securely close the drive nozzle of the steam jet pump. Alternatively, it is possible to precede the steam jet pump provided in the steam supply line quick-closing valve, which takes over the Sicherheitsabschaltfunktion. This solution is particularly suitable for systems with several parallel-working steam jet pump plate heat exchanger pairs. With a quick-closing valve, all steam jet pump plate heat exchanger pairs can be protected.

The quick-closing device can also be a vapor pressure-operated device, for example a diaphragm drive. The advantage of such a solution lies in the independence of an electrical power supply.

The inventive concept allows the economic utilization and recovery of waste heat, which has so far been unused due to lack of use or low energy density. Such waste energy is available, for example, as low-pressure steam, as obtained in industrial processes, such as treatment processes, cooking processes or the like.

In addition, the inventive concept allows the use of plate heat exchangers in connection with hot steam, i. an energy carrier with very high energy density, high temperature and high pressure. Furthermore, the invention allows the circumvention of otherwise given revision and licensing requirements.

• 1 eine Wärmeübertragungseinrichtung in vereinfachter schematisierter Form;
• 2 eine Antriebseinrichtung mit Schnellschluss für die Dampfstrahlpumpe in schematisierter Darstellung.

Embodiments of the invention are the subject of claims, the drawings and the accompanying description. Show it:

• 1 a heat transfer device in a simplified schematic form;
• 2 a drive device with quick closure for the steam jet pump in a schematic representation.

In 1 is a heat transfer device 10 illustrated with over a steam pipe 11 operated steam is operated. The one from the steam line 11 brought steam preferably has a temperature of more than 110 ° C, for example 200 ° C. It is condensed to heat use and can via a condensate line 12 derived and supplied, for example, a steam generator. The condensate line 12 supplied condensate can be largely cooled and depressurized.

From the steam line 11 branches a steam supply line 13 which leads to a propellant connection 14 a steam jet pump 15 leads. This also has a suction port 16 on that via a suction line 17 with a low pressure steam source 18 connected is. This is from the steam jet pump 15 Low pressure steam with ambient pressure, a slight negative pressure or even a slight overpressure of, for example, only 0.2 bar excess pressure taken. At the low pressure steam source 18 It can be as shown by external heat sources, such as burners 19 , electric heaters or the like, supplied cooking kettles 20 act in which, for example, a meal, a mash or the like is cooked and cooking vapors, ie vapors arise. About the suction line 17 become such vapors as low-pressure steam from the special low-pressure steam source 18 aspirated. Except cooking kettles 20 come as low-pressure steam sources, other low-pressure steam sources in question, for example, condensate collection vessels 21 , Evaporator, in which water is used as a refrigerant for generating cold under considerable negative pressure, or the like.

The steam jet pump 15 has a diffuser connection 22 on which a mixture of the via the steam supply line 13 and over the suction line 17 supplied steam to a primary flow line 23 is delivered. This leads to a primary flow connection 25 a plate heat exchanger 24 , At its primary return port 26 gives the plate heat exchanger 24 Condensate, cooled steam and / or a condensate / steam mixture to a primary return line 27 from. This leads either directly to the condensate line 12 , or to the condensate collection vessel 21 , For condensate cooling, a condensate heat exchanger 28 be provided with the primary input 29 the primary return line 27 connected is. Its primary output 30 can over a line 31 with the condensate collector 21 or via a line 32 with the condensate line 12 be connected.

The plate heat exchanger 24 has a secondary flow connection 33 on, via a secondary supply line 34 Hot water for heating purposes to heat consumers 35 , For example, in the form of radiators emits. That in the heat consumers 35 cooled water is via a secondary return line 36 to the secondary return connection 37 returned to the plate heat exchanger. In the secondary return line 36 and / or the secondary supply line 34 For example, a pump, for example an electrically operated pump, for example a centrifugal pump or the like, may be provided.

The condensate heat exchanger 28 is preferably a plate heat exchanger. It can be connected to a secondary flow connection 38 via a secondary supply line 39 heated water to a heat consumer, for example, a hot water circuit, submit the a water heater 40 may contain. Other heat consumers, such as heaters, process heat consumers or the like can also be fed. The condensate heat exchanger 28 also has a secondary return port 41 on, to him cold water, such as tap water or the like via a feed line 42 and optionally a pump 43 is supplied.

The steam jet pump 15 has an actuator 44 on, that with a drive device 45 connected is. The drive device 45 is preferably quick-acting. It can contain a spring accumulator, which in case of failure, the actuator 44 immediately moves to the closed position. In addition, it can be connected to other devices, such as limit switches, remote encoder, transducer or the like.

To control the operation of the steam jet pump 15 is a control device 46 provided, which may be formed for example by one or more microcontroller or the like. The control device 46 generates a control signal S for the drive device 45 so that this is the actuator 44 according to the specification of the control device 46 positioned.

At the primary supply line 23 and / or the plate heat exchanger 24 is at least one pressure sensor 47 and if desired, a primary temperature sensor 48 arranged. The pressure sensor 47 generates a pressure signal p that in the primary flow line 23 and thus on the primary side in the Plate heat exchanger 24 characterized by prevailing pressure. The primary temperature sensor 48 generates a primary temperature signal tp that the temperature in the primary supply line 23 features. The signals p and tp can over a bus 50 or other suitable lines or means to the controller 46 be transmitted. In addition, at the secondary supply line 34 a secondary temperature sensor 49 be provided, which is a secondary temperature signal ts generated in the secondary supply line 34 ruling temperature.

Optionally, in addition to the steam jet pump 15 and the plate heat exchanger 24 further, identical or similar constructed I groupings, at least on the primary side to be arranged in parallel.

Out 1 is such a steam jet pump 15 ' and an associated plate heat exchanger 24 ' seen. The above description of the steam jet pump 15 and the plate heat exchanger 24 applies accordingly, with the introduced reference numerals for differentiation in the steam jet pump 15 ' and the plate heat exchanger 24 ' each marked with an apostrophe ('). The plate heat exchanger 24 ' For its part, it can heat heat consumers of any kind, such as, for example, the hot water circuit or even heaters or process heat consumers. The one of his steam jet pump 15 ' associated control device 46 ' may be a separate control device or with the control device 46 to a single controller 51 be united.

In a modified embodiment, in the steam supply line 13 a quick-acting valve be provided by a pressure switch or the control device 46 is closed, if in one of the primary supply lines 23 . 23 ' exceeding the limit pressure p _G is detected. This variant is particularly suitable for systems with multiple steam jet pump plate heat exchanger pairs. In this case, require the drive devices 45 no fast-closing feature.

The heat transfer device described so far 10 works as follows:

In operation is at the steam line 11 strained steam at a pressure which may be greater than the design-related primary side for the plate heat exchanger 24 permissible pressure. If the system is now to be put into operation, the control device opens 46 by means of the drive device 45 by movement of the actuator 44 the steam jet pump 15 something, so over the steam supply line 13 strained steam with example 12 bar overpressure through the jet nozzle of the steam jet pump 15 flows. This results in a known manner, a suction on the suction line 17 , In the low-pressure steam source 18 , for example, in the burner 19 heated cauldron 20 resulting vapors, ie wet steam at a comparatively low temperature and ambient pressure or only slightly elevated pressure (0.2 bar), from the steam jet pump 15 over the suction line 17 sucked.

The steam jet pump 15 works with a high degree of mixing. In the diffuser, only a small part of the originally existing vapor pressure is rebuilt, so that in the primary flow line 23 only a slight overpressure of, for example, only 0.5 barü is present. The control device 46 compares that from the pressure sensor 47 delivered pressure signal p constantly with a limit pressure p _G , for example, is set to 1 bar, 0.7 bar or any other suitable value. Preferably, the limit pressure p _G set to a value that is so low that the heat transfer device 10 not TÜV-supervised. Preferably, the control device triggers 46 in all embodiments, when the limit pressure is reached or exceeded, a quick closure of the jet pump 15 out.

The control device 46 also detects at least either the primary temperature or the secondary temperature and regulates via the drive 45 and the actuator 44 the steam flow so that the desired secondary flow temperature of, for example, 90 ° C is generated and maintained.

The temperature control described so far is superordinate pressure control or pressure shutdown. Represents the controller 46 notice that the pressure p the limit pressure p _G reached, the steam flow is throttled, even if the signal ts or tp not reached the desired value. The pressure control thus has a higher priority than the temperature control. Will the limit pressure p _G exceeded, the control device 46 initiate a quick-closing, in which the actuator 44 the steam jet pump 15 closes and the steam flow through the steam supply line 13 off. This will cause a pressure overload of the plate heat exchanger 24 safely excluded.

The control device 46 may be such that after a short circuit after falling below the limit pressure p _G the steam jet pump 15 again opens something to start normal operation. At the same time, it is possible to provide that a message is sent to a higher-level controller, to a central office or to a system maintenance service in order to signal that a fast-closing has taken place.

2 shows a heat transfer device 10 ' partial and schematic. The previous description applies with the exceptions described below accordingly: The drive device 45 includes a pneumatic drive, eg a diaphragm drive. This one is with a positioner 52 connected, which detects the position of the adjusting spindle and with one of the control device 46 supplied signal compares. In accordance with the established control deviation, the pneumatic drive is subjected to more or less pressure in order to drive the adjusting spindle immediately into the required position. The pneumatic drive has quick-closing characteristics. It preferably closes in the current or depressurized state by means of a closing spring, the steam jet pump 15 immediately. This makes us the plate heat exchanger 24 effective against the high pressure of the steam supply line 13 protected. Even when the set pressure limit for the plate heat exchanger is exceeded, for example from 0.5 bar, an immediate rapid adjustment of the adjusting spindle for pressure reduction can take place.

A heat transfer device according to the invention 10 has a steam jet pump 15 and a plate heat exchanger 24 on, the primary side of the steam jet pump 15 fed with pressure and temperature reduced steam. The steam jet pump 15 in turn is fed with steam of considerably higher pressure. This pressure can be over one for the plate heat exchanger 24 permissible value. The steam jet pump allows the control of the secondary side flow temperature, the temperature and pressure moderate primary side protection of the plate heat exchanger, reducing the pressure of high pressure steam to eg only 0.5 barü, and at the same time the energy utilization of low-energy steam, for example by suction of Brüdendampf eg from cooking kettles.

LIST OF REFERENCE NUMBERS

10, 10 '

Heat transfer device

11

steam line

12

condensate line

13

Steam supply line

14, 14 '

Propellant connection

15, 15 '

Steam ejector

16, 16 '

suction

17

suction

18

Low pressure steam source

19

burner

20

cauldron

21

Condensate collection vessel

22, 22 '

diffuser port

23, 23 '

Primary flow line

24, 24 '

Plate heat exchanger

25, 25 '

Primary flow connection

26, 26 '

Primary return deadline

27

Primary return line

28

Plate heat exchanger / condensation heat exchanger

29

primary input

30

primary output

31, 32

management

33, 33 '

Secondary flow connection

34

Secondary supply line

35

heat consumer

36, 36 '

Secondary return line

37, 37 '

Secondary return connection

38

Secondary flow connection

39

Secondary supply line

40

Hot water heater

41

Secondary return connection

42

feeder

43

pump

44

actuator

45, 45 '

driving means

46, 46 '

control device

S

actuating signal

47, 47 '

pressure sensor

48, 49,

Primary temperature sensor / secondary temperature

48 ', 49'

sensor

p

pressure signal

50

bus

51

control device

p _G

limit pressure

tp

Primary temperature signal

ts

Secondary temperature signal

K

Condensate removal device

52

positioner

Claims (15)

Heat transfer device (10), in particular for local or district heat transfer, with at least one steam jet pump (15), which comprises: a propellant connection (14) which can be acted upon by steam via a steam supply line (13), a suction connection (16) connected to a low pressure steam source (18) via a suction line (17), a diffuser connection (22) and an actuator (44) for influencing the flow of steam passing through the propellant port (14), comprising: a primary flow port (25) connected to at least one plate heat exchanger (24) via a primary flow line (23) to the diffuser port (22) of the jet pump (15); , a primary return connection (26) connected via a primary return line (27) to a condensate discharge device (K), a secondary flow connection (33) connected to a heat consumer (35) via a secondary supply line (34) and a secondary return line (36) to the heat consumer ( 35) connected secondary return port (37), with a Pressure sensing means (47) connected to the primary flow line (23) for generating a pressure signal (p) indicative of the pressure prevailing in the primary flow line (23) with at least one control means (51, 46) connected to the pressure sensing means (47) is connected to receive the pressure signal (p) with at least one drive means (45) connected to the control means (51, 46) for receiving the control signal (S) and communicating with the actuator (44 ) is connected to the steam flow on the basis of the control signal (S) to adjust such that a limiting pressure (p _G ) in the primary flow line (23) is not exceeded, each steam jet pump (15) is associated with a control device (51, 46) , Heat transfer device after Claim 1 characterized in that the primary flow line (23) and / or the plate heat exchanger (24) is connected to a primary temperature sensor (48) adapted to generate a primary temperature signal (tp) indicative of the sensed temperature, the control means (51, 46) is connected to the temperature sensor (48) to receive the primary temperature signal (tp). Heat transfer device after Claim 2 characterized in that the control means (51, 46) is arranged to receive the primary temperature signal (tp) and compare it to a threshold temperature to generate a drive signal (45) control signal to reduce the vapor flow such that the limit temperature in the primary flow line (23) is not exceeded. Heat transfer device according to one of the preceding claims, characterized in that the secondary supply line (34) and / or the heat consumer (35) is connected to a secondary temperature sensor (49) which is adapted to generate a temperature signal indicative of the detected secondary temperature (ts), wherein the control means (51, 46) is connected to the secondary temperature sensor (49) to receive the secondary temperature signal (ts). Heat transfer device after Claim 1 , characterized in that the Kondensatabführungseinrichtung (K) has a condensate heat exchanger (28) which is connected on the primary side to the primary return line (27) to the at least one plate heat exchanger (24) emitted steam or discharged condensate or a discharged vapor / condensate mixture take. Heat transfer device after Claim 5 , characterized in that the condensate heat exchanger (28) is a plate heat exchanger. Heat transfer device after Claim 5 or 6 , characterized in that the condensate heat exchanger (28) is connected on the secondary side with a heat consumer. Heat transfer device according to one of the preceding claims, characterized in that at least two steam jet pumps (15, 15 ') and at least two plate heat exchangers (24, 24') are provided, wherein the diffuser port (22, 22 ') of each jet pump (15, 15') each with a primary flow connection (25, 25 ') of the plate heat exchanger (24, 24') is connected. Heat transfer device after Claim 8 , characterized in that the propellant connections (14, 14 ') of the two steam jet pumps (15, 15') are connected to the same steam supply line (13). Heat transfer device after Claim 8 or 9 , characterized in that in the primary return line (27), a check valve or a check valve is arranged. Heat transfer device according to one of Claims 8 to 10 , characterized in that the suction ports (16, 16 ') of the steam jet pumps (15, 15') are interconnected. Heat transfer device according to one of the preceding claims, characterized in that the steam jet pump (15, 15 ') has a quick-closing device or the Steam jet pump (15, 15 ') a quick-closing valve is connected upstream. Heat transfer device according to one of the preceding claims, characterized in that the suction line (17) contains at least one control valve which is connected to the control device (51, 46). Heat transfer device according to one of the preceding claims, characterized in that the low-pressure steam source (18) is a process heat consumer. Method for operating a heat transfer device (10) with a steam jet pump (15) whose diffuser port (22) is connected to the primary flow of the plate heat exchanger (24), wherein the steam jet pump (15) is controlled by a control device (51, 46), so that the Steam jet pump (15) are assigned at the same time several functions, namely: a) the regulation of the secondary-side flow temperature, b) the pressurized protection of the plate heat exchanger (24) by quick closure, c) the pressure reduction of the high-pressure steam from a value which is not permitted for the plate heat exchanger (24) to a limit which is permissible for the plate heat exchanger (24) and which classifies the installation as non-monitorable, d) suction of exhaust steam from other processes or condensate collection vessels (21).

Images