EP3006875A1 - Method for regulating a coupled heat exchanger system and heat exchanger system - Google Patents

Method for regulating a coupled heat exchanger system and heat exchanger system Download PDF

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Publication number
EP3006875A1
EP3006875A1 EP14003476.0A EP14003476A EP3006875A1 EP 3006875 A1 EP3006875 A1 EP 3006875A1 EP 14003476 A EP14003476 A EP 14003476A EP 3006875 A1 EP3006875 A1 EP 3006875A1
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EP
European Patent Office
Prior art keywords
heat exchanger
flow
fluid
exchanger system
partial flow
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP14003476.0A
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German (de)
French (fr)
Inventor
Valdo Bahner
Thomas Hecht
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Linde GmbH
Original Assignee
Linde GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Linde GmbH filed Critical Linde GmbH
Priority to EP14003476.0A priority Critical patent/EP3006875A1/en
Priority to EA201790797A priority patent/EA201790797A1/en
Priority to CN201580054538.3A priority patent/CN106796081B/en
Priority to KR1020177012429A priority patent/KR20170066595A/en
Priority to EP15781577.0A priority patent/EP3204704A1/en
Priority to US15/513,167 priority patent/US10345040B2/en
Priority to PCT/EP2015/001980 priority patent/WO2016055162A1/en
Publication of EP3006875A1 publication Critical patent/EP3006875A1/en
Withdrawn legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04763—Start-up or control of the process; Details of the apparatus used
    • F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
    • F25J3/04787—Heat exchange, e.g. main heat exchange line; Subcooler, external reboiler-condenser
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04763—Start-up or control of the process; Details of the apparatus used
    • F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
    • F25J3/04854—Safety aspects of operation
    • F25J3/0486—Safety aspects of operation of vaporisers for oxygen enriched liquids, e.g. purging of liquids
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
    • F25J3/04078—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression
    • F25J3/0409—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression of oxygen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
    • F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
    • F25J3/04193—Division of the main heat exchange line in consecutive sections having different functions
    • F25J3/042—Division of the main heat exchange line in consecutive sections having different functions having an intermediate feed connection
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
    • F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
    • F25J3/04193—Division of the main heat exchange line in consecutive sections having different functions
    • F25J3/04206—Division of the main heat exchange line in consecutive sections having different functions including a so-called "auxiliary vaporiser" for vaporising and producing a gaseous product
    • F25J3/04212—Division of the main heat exchange line in consecutive sections having different functions including a so-called "auxiliary vaporiser" for vaporising and producing a gaseous product and simultaneously condensing vapor from a column serving as reflux within the or another column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
    • F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
    • F25J3/04218—Parallel arrangement of the main heat exchange line in cores having different functions, e.g. in low pressure and high pressure cores
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04375—Details relating to the work expansion, e.g. process parameter etc.
    • F25J3/04393—Details relating to the work expansion, e.g. process parameter etc. using multiple or multistage gas work expansion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D9/00—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
    • F28D9/0093—Multi-circuit heat-exchangers, e.g. integrating different heat exchange sections in the same unit or heat-exchangers for more than two fluids
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F27/00—Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus
    • F28F27/02—Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus for controlling the distribution of heat-exchange media between different channels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/26—Arrangements for connecting different sections of heat-exchange elements, e.g. of radiators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
    • F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
    • F25J3/04218—Parallel arrangement of the main heat exchange line in cores having different functions, e.g. in low pressure and high pressure cores
    • F25J3/04224—Cores associated with a liquefaction or refrigeration cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04406—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system
    • F25J3/04412—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system in a classical double column flowsheet, i.e. with thermal coupling by a main reboiler-condenser in the bottom of low pressure respectively top of high pressure column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
    • F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
    • F28D2021/0033—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for cryogenic applications

Definitions

  • the invention relates to a method for controlling a coupled heat exchanger system according to the preamble of patent claim 1.
  • EP 1150082 A1 shows a heat exchanger system in which a first fluid stream, which is formed by atmospheric air, is cooled in a heat exchanger system in countercurrent to a second fluid stream (nitrogen) and a third fluid stream (oxygen).
  • the heat exchanger system has a plurality of parallel heat exchanger blocks.
  • a “mass flow control device” is understood here to mean any device which specifically influences the mass flow of a fluid.
  • a mass flow control device may be formed, for example, as a manual valve, control valve, flap or fixed aperture.
  • the invention has for its object to operate a heat exchanger system of the type mentioned so that the heat exchange is carried out particularly efficiently and a particularly long service life of the heat exchanger blocks is achieved.
  • This object is achieved in that an intermediate temperature is measured at one of the two heat exchanger blocks between the hot and the cold end and is set as a function of the current value of this intermediate temperature, which part of the first fluid flow goes into the first partial flow and which in the second partial flow.
  • the division of the first fluid flow onto the blocks is carried out in such a way that the intermediate temperature comes as close as possible to its desired value.
  • variable temperature profiles can be measured very accurately and influenced quickly.
  • These altered temperature profiles inside the heat exchangers can not be detected with sufficient accuracy by observing the inlet and outlet temperatures.
  • the temperature profiles inside the heat exchanger change before the change in the outlet temperatures becomes visible.
  • a control based on the measurement of the inlet and outlet temperatures can therefore react to deviations of the temperature profiles only very late.
  • an intermediate temperature can also be measured at both heat exchanger blocks;
  • the heat exchanger system of the invention may also have more than two, for example three or four or even more heat exchanger blocks.
  • a first mass flow actuator is disposed in the conduit of the first substream upstream or downstream of the heat exchanger system, and a second mass flow actuator is in the conduit of the second substream upstream or downstream of the heat exchanger system; one of these two mass flow control devices is designed as a control valve and is set in dependence on the current value of the intermediate temperature.
  • the other mass flow control device may have various types, such as manual valve, control valve, flap or fixed orifice.
  • the mass flow actuators may be located upstream or downstream of the corresponding heat exchanger block. The valves should be tightly closed to protect the heat exchanger blocks at standstill.
  • the first fluid stream in the heat exchanger system is cooled, and the second and third fluid streams are warmed in the heat exchanger system.
  • the first fluid stream in the heat exchanger system is warmed and the second and third fluid streams are cooled in the heat exchanger system.
  • the first and the second variant can also be combined by - starting from the first variant - the second and the third fluid flow are formed by partial flows of a fourth fluid flow;
  • a second intermediate temperature is measured on that of the two heat exchanger blocks, on which not the first intermediate temperature is measured; the measurement of the second intermediate temperature is measured between the warm and the cold end.
  • this second intermediate temperature it is set which part of the fourth fluid flow goes into the second fluid flow and which into the third fluid flow.
  • the invention is applied twice, so to speak, namely both a split stream to be cooled (the first fluid stream) and a split stream to be heated (fourth stream of fluid).
  • measuring and adjusting devices are mainly shown.
  • Other measuring and control devices have been omitted as a rule for the sake of clarity.
  • additional devices such as valves are to be arranged.
  • the heat exchanger system of FIG. 1 consists of a first heat exchanger block 1 and a second heat exchanger block 2.
  • a "first fluid stream” 3 is divided into a "first partial stream” 4 and a “second partial stream” 5 and cooled in the two blocks 1, 2 of the heat exchanger system.
  • a second fluid flow 6 and a third fluid flow 7 are warmed, the second fluid flow 6 in the first heat exchanger block 1, the third fluid flow 7 in the second heat exchanger block 2.
  • the warmed second fluid stream 10 and the warmed third fluid stream 11 are withdrawn.
  • the cooled part streams are combined and withdrawn as a cooled first fluid stream 12.
  • valves 13 and 14 are shown in the first fluid flow.
  • valves may be required for the operation of the heat exchanger system.
  • the valve 14 is designed as a valve with a fixed control variable and is preset.
  • the valve 14 is ideally 100% open, but must be closed by hand, or via a corresponding control function to increase the pressure loss across heat exchanger block 1, if the distribution of pressure losses is so unfavorable that the temperature profile is no longer alone on the valve 13 can be regulated.
  • the signal line contains a controller, not shown, which transmits the regulating valve 13 the value to be set for the flow in the second partial flow 5.
  • the controller can be formed by an analog electronic circuit or a digital device (for example, signal processor, memory program control, microprocessor) or alternatively realized in the process control system.
  • the aim of the control is to achieve the best possible temperature profile over the height of the heat exchanger blocks.
  • the target value of the temperature TI is determined by a theoretically determined temperature profile and the exact location of the temperature measurement. This target value can be fixed. Alternatively, the target value is given variable in time, for example in the case of changing process conditions such as, for example, variable inlet temperatures of the streams. It may be useful to also measure the temperatures at the warm and / or cold end of the heat exchanger blocks and include in the scheme.
  • the first fluid flow is formed by air, the second fluid flow by nitrogen and the third fluid flow by oxygen.
  • the invention can also be realized if the drawing is tilted vertically and thus the first fluid stream is the stream to be cooled.
  • FIG. 2 corresponds largely FIG. 1 , Here, however, a current to be heated is divided between the two heat exchanger blocks 1, 2.
  • a fourth fluid stream 20 is branched into the second fluid stream 6 and the third fluid stream 7.
  • the warmed second fluid stream 10 and the warmed third fluid stream 11 are then combined again to a heated fourth fluid stream 21.
  • a fifth fluid flow 26/27 flows through the first heat exchanger block 1.
  • the second and third fluid streams are operated as follows in the embodiment.
  • the valve 22 is configured as a manual valve and preset.
  • the valve 23 is designed as a control valve; its setting is dependent on the temperature difference TI1 - TI2; The aim of the scheme is to keep this difference at zero, that is to bring the temperatures of the cold end of both heat exchanger blocks to the same level.
  • the regulation of the first fluid flow takes place as in the example of FIG. 1 depending on the intermediate temperature TI.
  • the first fluid flow is formed by air, the fourth fluid flow by nitrogen and the fifth fluid flow by oxygen.
  • FIG. 3 the control method according to the invention is applied twice, so to speak, in a heat exchanger system with three heat exchanger blocks 301, 302, 303.
  • An air stream 304 is passed through the heat exchanger system in four sub-streams 305, 306, 307, 308 and reunited in line 309.
  • a gaseous nitrogen product stream 310 is passed in two partial streams 311 and 312 through the left heat exchanger block 301 and through the right heat exchanger block 303, thereby warmed to approximately ambient temperature and reunited in line 313.
  • liquid pressurized oxygen 314 is first vaporized (or pseudo-vaporized if its pressure is supercritical) and then warmed to about ambient temperature.
  • a partial flow 316 of a high-pressure air flow 315 is liquefied or pseudo-liquefied.
  • Another partial stream 317 of the high-pressure air 315 is cooled in the heat exchanger block only to an intermediate temperature and then fed to an expansion turbine, not shown.
  • the partial flow 306 of the air flow 304 serves as a compensating flow between heat exchanger blocks 301 and 302. It is taken from the block 302 at an intermediate temperature and introduced into the block 301 at a location corresponding to this intermediate temperature.
  • the "first substream" of claim 1 is formed by the stream 305 and the "second substream” by the stream 307.
  • the distribution of these two air streams to the two heat exchanger blocks 301 and 302 is carried out as a function of an intermediate temperature TIa of the heat exchanger block 302.
  • This intermediate temperature Tla is measured in the stream 306 after leaving the heat exchanger block 302 and before entering the heat exchanger block 301.
  • the temperature measurement TIa influences the opening of the valve 319.
  • an intermediate temperature Tlb is measured on the surface of the heat exchanger block 303.
  • the "first partial flow” of patent claim 1 is formed by the nitrogen flow 311, the “second partial flow” by the nitrogen flow 312.
  • the opening of the valve 320 is adjusted as a function of the temperature Tlb.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Emergency Medicine (AREA)
  • Control Of Temperature (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

Abstract

Das Verfahren dient zur Regelung eines gekoppelten Wärmetauscher-Systems, das einen ersten Wärmetauscherblock (1) und einen zweiten Wärmetauscherblock (2) aufweist. Ein erster Fluidstrom (3) fließt aufgeteilt in einen ersten Teilstrom (4) und einen zweiten Teilstrom (5) durch das Wärmetauscher-System. Ein zweiter Fluidstrom (6) wird im Gegenstrom zu dem ersten Teilstrom (4) durch den ersten Wärmetauscherblock (1) geleitet. Ein dritter Fluidstrom (7) wird im Gegenstrom zu dem zweiten Teilstrom (5) durch den zweiten Wärmetauscherblock (2) geleitet. An einem der beiden Wärmetauscherblöcke (1, 2) wird eine Zwischentemperatur (T1) gemessen. In Abhängigkeit vom aktuellen Wert dieser Zwischentemperatur (TI)wird eingestellt, welcher Teil des ersten Fluidstroms (3) in den ersten Teilstrom (4) geht und welcher in den zweiten Teilstrom (5).The method is used to control a coupled heat exchanger system comprising a first heat exchanger block (1) and a second heat exchanger block (2). A first fluid flow (3) flows divided into a first partial flow (4) and a second partial flow (5) through the heat exchanger system. A second fluid flow (6) is passed in countercurrent to the first partial flow (4) through the first heat exchanger block (1). A third fluid flow (7) is passed in countercurrent to the second partial flow (5) through the second heat exchanger block (2). At one of the two heat exchanger blocks (1, 2), an intermediate temperature (T1) is measured. Depending on the current value of this intermediate temperature (TI), it is set which part of the first fluid flow (3) goes into the first partial flow (4) and which into the second partial flow (5).

Description

Die Erfindung betrifft ein Verfahren zur Regelung eines gekoppelten Wärmetauscher-Systems gemäß dem Oberbegriff des Patentanspruchs 1.The invention relates to a method for controlling a coupled heat exchanger system according to the preamble of patent claim 1.

EP 1150082 A1 zeigt ein Wärmetauscher-System, bei dem ein erster Fluidstrom, der durch atmosphärische Luft gebildet wird, in einem Wärmetauscher-System im Gegenstrom zu einem zweiten Fluidstrom (Stickstoff) und einem dritten Fluidstrom (Sauerstoff) abgekühlt wird. Das Wärmetauscher-System weist mehrere parallele Wärmetauscherblöcke auf. EP 1150082 A1 shows a heat exchanger system in which a first fluid stream, which is formed by atmospheric air, is cooled in a heat exchanger system in countercurrent to a second fluid stream (nitrogen) and a third fluid stream (oxygen). The heat exchanger system has a plurality of parallel heat exchanger blocks.

Bei Wärmetauscher-Systemen mit sehr großem Temperaturgang und kleinen Temperaturdifferenzen können sehr kleine Änderungen der Mengenströme zu sehr unterschiedlichen Temperaturprofilen innerhalb der Wärmeaustauscher führen. Abweichungen von den in der Auslegung berechneten Temperaturprofilen können zu Ineffizienzen des Wärmeaustausches aber auch zu erhöhter mechanischer Beanspruchung und damit zu einer verringerten Lebensdauer der Wärmetauscherblöcke führen.For heat exchanger systems with very high temperature response and small temperature differences very small changes in the flow rates can lead to very different temperature profiles within the heat exchanger. Deviations from the temperature profiles calculated in the design can lead to inefficiencies of the heat exchange but also to increased mechanical stress and thus to a reduced service life of the heat exchanger blocks.

Unter einer "Massenstrom-Stelleinrichtung" wird hier jede Vorrichtung verstanden, die den Massenstrom eines Fluids gezielt beeinflusst. Eine Massenstrom-Stelleinrichtung kann zum Beispiel als Handventil, Regelventil, Klappe oder feste Blende ausgebildet sein.A "mass flow control device" is understood here to mean any device which specifically influences the mass flow of a fluid. A mass flow control device may be formed, for example, as a manual valve, control valve, flap or fixed aperture.

Der Erfindung liegt die Aufgabe zugrunde, ein Wärmetauscher-System der eingangs genannten Art so zu betreiben, dass der Wärmeaustausch besonders effizient durchgeführt und eine besonders hohe Lebensdauer der Wärmetauscherblöcke erreicht wird.The invention has for its object to operate a heat exchanger system of the type mentioned so that the heat exchange is carried out particularly efficiently and a particularly long service life of the heat exchanger blocks is achieved.

Diese Aufgabe wird dadurch gelöst, dass an einem der beiden Wärmetauscherblöcke zwischen dem warmen und dem kalten Ende eine Zwischentemperatur gemessen wird und in Abhängigkeit vom aktuellen Wert dieser Zwischentemperatur eingestellt wird, welcher Teil des ersten Fluidstroms in den ersten Teilstrom geht und welcher in den zweiten Teilstrom. Es wird also die Aufteilung des ersten Fluidstroms auf die Blöcke so durchgeführt, dass die Zwischentemperatur ihrem Sollwert möglichst nahe kommt.This object is achieved in that an intermediate temperature is measured at one of the two heat exchanger blocks between the hot and the cold end and is set as a function of the current value of this intermediate temperature, which part of the first fluid flow goes into the first partial flow and which in the second partial flow. Thus, the division of the first fluid flow onto the blocks is carried out in such a way that the intermediate temperature comes as close as possible to its desired value.

Im Rahmen der Erfindung hat sich herausgestellt, dass dadurch insbesondere veränderliche Temperaturprofile sehr genau gemessen und schnell beeinflusst werden können. Diese veränderten Temperaturprofile im Innern der Wärmeaustauscher können über die Beobachtung der Ein- und Austrittstemperaturen nicht hinreichend genau detektiert werden. Die Temperaturprofile im Innern des Wärmeaustauschers verändern sich, bevor die Veränderung an den Austrittstemperaturen sichtbar wird. Eine Regelung, die auf der Messung der Ein- und Austrittstemperaturen basiert, kann somit auf Abweichungen der Temperaturprofile erst sehr spät reagieren.In the context of the invention, it has been found that in particular variable temperature profiles can be measured very accurately and influenced quickly. These altered temperature profiles inside the heat exchangers can not be detected with sufficient accuracy by observing the inlet and outlet temperatures. The temperature profiles inside the heat exchanger change before the change in the outlet temperatures becomes visible. A control based on the measurement of the inlet and outlet temperatures can therefore react to deviations of the temperature profiles only very late.

Natürlich kann im Rahmen der Erfindung auch an beiden Wärmetauscherblöcken eine Zwischentemperatur gemessen werden; außerdem kann das Wärmetauscher-System der Erfindung auch mehr als zwei, zum Beispiel drei oder vier oder auch mehr Wärmetauscherblöcke aufweisen.Of course, in the context of the invention, an intermediate temperature can also be measured at both heat exchanger blocks; In addition, the heat exchanger system of the invention may also have more than two, for example three or four or even more heat exchanger blocks.

Für die Messung der Zwischentemperatur eines Wärmetauscherblocks kann jede bekannte Methode verwendet werden, zum Beispiel

  • eine Messung der Temperatur auf einer äußeren Oberfläche des Wärmetauscherblocks ( DE 102007021564 A1 ),
  • eine Messung der Fluidtemperatur an einem Zwischenabzug,
  • eine Messanordnung gemäß DE 202013008316 U1 , oder
  • eine Messung mit Lichtwellenleiter nach DE 102007021564 A1 .
For the measurement of the intermediate temperature of a heat exchanger block, any known method can be used, for example
  • a measurement of the temperature on an outer surface of the heat exchanger block ( DE 102007021564 A1 )
  • a measurement of the fluid temperature at an intermediate exhaust,
  • a measuring arrangement according to DE 202013008316 U1 , or
  • a measurement with optical fibers after DE 102007021564 A1 ,

In einer speziellen Ausführungsform der Erfindung ist eine erste Massenstrom-Stelleinrichtung in der Leitung des ersten Teilstroms stromaufwärts oder stromabwärts des Wärmetauscher-Systems angeordnet und eine zweite Massenstrom-Stelleinrichtung ist in der Leitung des zweiten Teilstroms stromaufwärts oder stromabwärts des Wärmetauscher-Systems; eine dieser beiden Massenstrom-Stelleinrichtungen ist als Regelventil ausgebildet und wird in Abhängigkeit vom aktuellen Wert der Zwischentemperatur eingestellt. Die andere Massenstrom-Stelleinrichtung kann verschiedene Bauarten aufweisen, wie zum Beispiel Handventil, Regelventil, Klappe oder feste Blende. Für die Einstellung des ersten Fluidstroms sind also genau zwei Massenstrom-Stelleinrichtungen notwendig, eines im ersten und eines im zweiten Teilstrom, wobei mindestens eines davon als Regelventil ausgebildet ist. Die Massenstrom-Stelleinrichtungen können stromaufwärts oder stromabwärts des entsprechenden Wärmetauscherblocks angeordnet sein. Die Armaturen sollten zur Absicherung der Wärmetauscherblöcke im Stillstand dichtschließend ausgeführt sein.In a specific embodiment of the invention, a first mass flow actuator is disposed in the conduit of the first substream upstream or downstream of the heat exchanger system, and a second mass flow actuator is in the conduit of the second substream upstream or downstream of the heat exchanger system; one of these two mass flow control devices is designed as a control valve and is set in dependence on the current value of the intermediate temperature. The other mass flow control device may have various types, such as manual valve, control valve, flap or fixed orifice. For the adjustment of the first fluid flow are So exactly two mass flow control devices necessary, one in the first and one in the second partial flow, at least one of which is designed as a control valve. The mass flow actuators may be located upstream or downstream of the corresponding heat exchanger block. The valves should be tightly closed to protect the heat exchanger blocks at standstill.

In einer ersten Variante der Erfindung wird der erste Fluidstrom in dem Wärmetauscher-System abgekühlt, und der zweite und der dritte Fluidstrom werden in dem Wärmetauscher-System angewärmt.In a first variant of the invention, the first fluid stream in the heat exchanger system is cooled, and the second and third fluid streams are warmed in the heat exchanger system.

In einer zweiten Variante wird umgekehrt der erste Fluidstrom in dem Wärmetauscher-System angewärmt, und der zweite und der dritte Fluidstrom werden in dem Wärmetauscher-System abgekühlt.Conversely, in a second variant, the first fluid stream in the heat exchanger system is warmed and the second and third fluid streams are cooled in the heat exchanger system.

Die erste und die zweite Variante können auch kombiniert werden, indem - ausgehend von der ersten Variante - der zweite und der dritte Fluidstrom durch Teilströme eines vierten Fluidstroms gebildet werden; außerdem wird eine zweite Zwischentemperatur gemessen an demjenigen der beiden Wärmetauscherblöcke, an dem nicht die erste Zwischentemperatur gemessen wird; die Messung der zweiten Zwischentemperatur wird zwischen dem warmen und dem kalten Ende gemessen. In Abhängigkeit vom aktuellen Wert dieser zweiten Zwischentemperatur wird eingestellt, welcher Teil des vierten Fluidstroms in den zweiten Fluidstrom geht und welcher in den dritten Fluidstrom.The first and the second variant can also be combined by - starting from the first variant - the second and the third fluid flow are formed by partial flows of a fourth fluid flow; In addition, a second intermediate temperature is measured on that of the two heat exchanger blocks, on which not the first intermediate temperature is measured; the measurement of the second intermediate temperature is measured between the warm and the cold end. Depending on the current value of this second intermediate temperature, it is set which part of the fourth fluid flow goes into the second fluid flow and which into the third fluid flow.

Hier wird die Erfindung sozusagen zweimal angewendet, nämlich sowohl auf einen aufgeteilten abzukühlenden Strom (den ersten Fluidstrom) und auf einen aufgeteilten anzuwärmenden Strom (vierter Fluidstrom).Here, the invention is applied twice, so to speak, namely both a split stream to be cooled (the first fluid stream) and a split stream to be heated (fourth stream of fluid).

Die Erfindung sowie weitere Einzelheiten der Erfindung werden im Folgenden anhand von in den Zeichnungen schematisch dargestellten Ausführungsbeispielen näher erläutert. Hierbei zeigen:

Figur 1
ein erstes Ausführungsbeispiel der Erfindung mit zwei Wärmetauscherblöcken,
Figur 2
ein zweites Ausführungsbeispiel der Erfindung mit zwei Wärmetauscherblöcken und
Figur 3
ein drittes Ausführungsbeispiel mit drei Wärmetauscherblöcken.
The invention and further details of the invention are explained below with reference to embodiments schematically illustrated in the drawings. Hereby show:
FIG. 1
A first embodiment of the invention with two heat exchanger blocks,
FIG. 2
A second embodiment of the invention with two heat exchanger blocks and
FIG. 3
a third embodiment with three heat exchanger blocks.

In den Zeichnungen sind hauptsächlich die für die Erläuterung und Funktion der Erfindung notwendigen Mess- und Stelleinrichtungen dargestellt. Weitere Mess- und Stelleinrichtungen wurden in der Regel der Übersichtlichkeit halber weggelassen. Der Fachmann weiß, an welcher Stelle gegebenenfalls zusätzliche Einrichtungen wie Ventile anzuordnen sind.In the drawings, the necessary for the explanation and function of the invention measuring and adjusting devices are mainly shown. Other measuring and control devices have been omitted as a rule for the sake of clarity. The person skilled in the art knows at which point, if necessary, additional devices such as valves are to be arranged.

Das Wärmetauscher-System von Figur 1 besteht aus einem ersten Wärmetauscherblock 1 und einem zweiten Wärmetauscherblock 2. Ein "erster Fluidstrom" 3 wird in einen "ersten Teilstrom" 4 und einen "zweiten Teilstrom" 5 aufgeteilt und in den beiden Blöcken 1, 2 des Wärmetauscher-Systems abgekühlt. Im Gegenstrom dazu werden ein zweiter Fluidstrom 6 und ein dritter Fluidstrom 7 angewärmt, der zweite Fluidstrom 6 im ersten Wärmetauscherblock 1, der dritte Fluidstrom 7 im zweiten Wärmetauscherblock 2.The heat exchanger system of FIG. 1 consists of a first heat exchanger block 1 and a second heat exchanger block 2. A "first fluid stream" 3 is divided into a "first partial stream" 4 and a "second partial stream" 5 and cooled in the two blocks 1, 2 of the heat exchanger system. In countercurrent thereto, a second fluid flow 6 and a third fluid flow 7 are warmed, the second fluid flow 6 in the first heat exchanger block 1, the third fluid flow 7 in the second heat exchanger block 2.

Am warmen Ende 8 der Wärmetauscherblöcke werden der angewärmte zweite Fluidstrom 10 und der angewärmte dritte Fluidstrom 11 abgezogen. Am kalten Ende 9 der Wärmetauscherblöcke werden die abgekühlten Teilströme vereinigt und als abgekühlter erster Fluidstrom 12 abgezogen.At the warm end 8 of the heat exchanger blocks, the warmed second fluid stream 10 and the warmed third fluid stream 11 are withdrawn. At the cold end 9 of the heat exchanger blocks, the cooled part streams are combined and withdrawn as a cooled first fluid stream 12.

In der Zeichnung sind nur die beiden Ventile 13 und 14 in dem ersten Fluidstrom dargestellt. Für den Betrieb des Wärmetauscher-Systems können weitere, hier nicht dargestellte Ventile erforderlich sein.In the drawing, only the two valves 13 and 14 are shown in the first fluid flow. For the operation of the heat exchanger system further, not shown here valves may be required.

Das Ventil 14 ist als Ventil mit fester Stellgröße ausgebildet und ist voreingestellt. Das Ventil 14 steht idealerweise zu 100% offen, muss jedoch von Hand, beziehungsweise über eine entsprechende Steuerfunktion geschlossen werden, um den Druckverlust über Wärmetauscherblock 1 zu erhöhen, wenn die Verteilung der Druckverluste so ungünstig ist, dass das Temperaturprofil nicht mehr allein über das Ventil 13 geregelt werden kann. Das Ventil 13 ist als Regelventil ausgebildet; seine Einstellung erfolgt erfindungsgemäß in Abhängigkeit von einer Temperaturmessung TI (TI = Temperature Indication) an einer Zwischenstelle 16 des zweiten Wärmetauscherblocks 2 zwischen dessen warmen und kalten Enden 8, 9. Die Signalleitung enthält einen nicht dargestellten Regler, der dem Regelventil 13 den einzustellenden Wert für den Durchfluss im zweiten Teilstrom 5 übermittelt. Der Regler kann durch eine analoge elektronische Schaltung oder ein digitales Gerät (zum Beispiel Signalprozessor, Speicherprogrammsteuerung, Mikroprozessor) gebildet oder alternativ im Prozessleitsystem realisiert werden.The valve 14 is designed as a valve with a fixed control variable and is preset. The valve 14 is ideally 100% open, but must be closed by hand, or via a corresponding control function to increase the pressure loss across heat exchanger block 1, if the distribution of pressure losses is so unfavorable that the temperature profile is no longer alone on the valve 13 can be regulated. The valve 13 is designed as a control valve; its setting is carried out according to the invention in dependence on a temperature measurement TI (TI = Temperature Indication) at an intermediate point 16 of the second heat exchanger block 2 between its hot and cold ends 8, 9. The signal line contains a controller, not shown, which transmits the regulating valve 13 the value to be set for the flow in the second partial flow 5. The controller can be formed by an analog electronic circuit or a digital device (for example, signal processor, memory program control, microprocessor) or alternatively realized in the process control system.

Ziel der Regelung ist es, ein möglichst optimales Temperaturprofil über die Höhe der Wärmetauscherblöcke zu erreichen. Der Zielwert der Temperatur TI wird durch ein theoretisch ermitteltes Temperaturprofil und den genauen Ort der Temperaturmessung festgelegt. Dieser Zielwert kann fest sein. Alternativ wird der Zielwert zeitlich veränderlich vorgegeben, etwa bei sich ändernden Prozessbedingungen wie zum Beispiel variablen Eintrittstemperaturen der Ströme. Es kann sinnvoll sein, auch die Temperaturen am warmen und/oder am kalten Ende des oder der Wärmetauscherblöcke zu messen und in die Regelung einzubeziehen.The aim of the control is to achieve the best possible temperature profile over the height of the heat exchanger blocks. The target value of the temperature TI is determined by a theoretically determined temperature profile and the exact location of the temperature measurement. This target value can be fixed. Alternatively, the target value is given variable in time, for example in the case of changing process conditions such as, for example, variable inlet temperatures of the streams. It may be useful to also measure the temperatures at the warm and / or cold end of the heat exchanger blocks and include in the scheme.

In einem konkreten Anwendungsfall aus der Tieftemperatur-Luftzerlegung werden der erste Fluidstrom durch Luft, der zweite Fluidstrom durch Stickstoff und der dritte Fluidstrom durch Sauerstoff gebildet.In a specific application from the cryogenic air separation, the first fluid flow is formed by air, the second fluid flow by nitrogen and the third fluid flow by oxygen.

Die Erfindung kann genauso verwirklicht werden, wenn man die Zeichnung vertikal kippt und damit der erste Fluidstrom der abzukühlende Strom ist.The invention can also be realized if the drawing is tilted vertically and thus the first fluid stream is the stream to be cooled.

Figur 2 entspricht weitgehend Figur 1. Hier wird allerdings auch ein anzuwärmender Strom auf die beiden Wärmetauscherblöcke 1, 2 aufgeteilt. Ein vierter Fluidstrom 20 wird in den zweiten Fluidstrom 6 und den dritten Fluidstrom 7 verzweigt. Der angewärmte zweite Fluidstrom 10 und der angewärmte dritte Fluidstrom 11 werden anschließend wieder zu einem angewärmte vierten Fluidstrom 21 vereinigt. FIG. 2 corresponds largely FIG. 1 , Here, however, a current to be heated is divided between the two heat exchanger blocks 1, 2. A fourth fluid stream 20 is branched into the second fluid stream 6 and the third fluid stream 7. The warmed second fluid stream 10 and the warmed third fluid stream 11 are then combined again to a heated fourth fluid stream 21.

Zusätzlich zum zweiten Fluidstrom 6 fließt ein fünfter Fluidstrom 26/27 durch den ersten Wärmetauscherblock 1.In addition to the second fluid flow 6, a fifth fluid flow 26/27 flows through the first heat exchanger block 1.

Zur Regelung des Wärmetauscher-Systems 1, 2 werden drei Temperaturen gemessen:

TI1:
Temperatur am kalten Ende des ersten Wärmetauscherblocks 1, Messung im abgekühlten ersten Teilstrom 4
TI2:
Temperatur am kalten Ende des zweiten Wärmetauscherblocks 2, Messung im abgekühlten zweiten Teilstrom 5
TI:
Zwischentemperatur, Messung an einer Zwischenstelle 16 des zweiten Wärmetauscherblocks 2 an der Oberfläche des Wärmetauscherblocks
To control the heat exchanger system 1, 2, three temperatures are measured:
TI1:
Temperature at the cold end of the first heat exchanger block 1, measurement in the cooled first partial flow 4th
TI2:
Temperature at the cold end of the second heat exchanger block 2, measurement in the cooled second partial flow. 5
TI:
Intermediate temperature, measurement at an intermediate point 16 of the second heat exchanger block 2 on the surface of the heat exchanger block

Der zweite und der dritte Fluidstrom werden in dem Ausführungsbeispiel folgendermaßen betrieben. Das Ventil 22 ist als Handventil ausgestaltet und voreingestellt. Das Ventil 23 ist als Regelventil ausgebildet; seine Einstellung erfolgt in Abhängigkeit von der Temperaturdifferenz TI1 - TI2; Ziel der Regelung ist, diese Differenz bei Null zu halten, das heißt die Temperaturen des kalten Endes beider Wärmetauscherblöcke auf gleiches Niveau zu bringen.The second and third fluid streams are operated as follows in the embodiment. The valve 22 is configured as a manual valve and preset. The valve 23 is designed as a control valve; its setting is dependent on the temperature difference TI1 - TI2; The aim of the scheme is to keep this difference at zero, that is to bring the temperatures of the cold end of both heat exchanger blocks to the same level.

Die Regelung des ersten Fluidstroms erfolgt wie in dem Beispiel der Figur 1 in Abhängigkeit von der Zwischentemperatur TI.The regulation of the first fluid flow takes place as in the example of FIG. 1 depending on the intermediate temperature TI.

In einem konkreten Anwendungsfall aus der Tieftemperatur-Luftzerlegung werden der erste Fluidstrom durch Luft, der vierte Fluidstrom durch Stickstoff und der fünfte Fluidstrom durch Sauerstoff gebildet.In a specific application from the cryogenic air separation, the first fluid flow is formed by air, the fourth fluid flow by nitrogen and the fifth fluid flow by oxygen.

In Figur 3 wird die erfindungsgemäße Regelungsmethode sozusagen zweimal angewendet, und zwar in einem Wärmetauscher-System mit drei Wärmetauscherblöcken 301, 302, 303.In FIG. 3 the control method according to the invention is applied twice, so to speak, in a heat exchanger system with three heat exchanger blocks 301, 302, 303.

Eine Luftstrom 304 wird in vier Teilströmen 305, 306, 307, 308 durch das Wärmetauscher-System geführt, und in Leitung 309 wieder vereint. Ein gasförmiger Stickstoff-Produktstrom 310 wird in zwei Teilströmen 311 und 312 durch den linken Wärmetauscherblock 301 beziehungsweise durch den rechten Wärmetauscherblock 303 geleitet, dabei auf etwa Umgebungstemperatur angewärmt und in Leitung 313 wieder vereint.An air stream 304 is passed through the heat exchanger system in four sub-streams 305, 306, 307, 308 and reunited in line 309. A gaseous nitrogen product stream 310 is passed in two partial streams 311 and 312 through the left heat exchanger block 301 and through the right heat exchanger block 303, thereby warmed to approximately ambient temperature and reunited in line 313.

Durch den Wärmetauscherblock 302 strömt außerdem ein Unreinstickstoffstrom 318 (Waste N2).Through the heat exchanger block 302 also flows impurity nitrogen stream 318 (Waste N2).

Im ersten WT 301 wird flüssig auf Druck gebrachter Sauerstoff 314 zunächst verdampft (beziehungsweise pseudo-verdampft, falls sein Druck überkritisch ist) und dann auf etwa Umgebungstemperatur angewärmt. Im Gegenstrom dazu wird ein Teilstrom 316 eines Hochdruck-Luftstroms 315 verflüssigt beziehungsweise pseudoverflüssigt. Ein anderer Teilstrom 317 der Hochdruckluft 315 wird im Wärmetauscherblock nur auf eine Zwischentemperatur abgekühlt und dann einer nicht dargestellten Expansionsturbine zugeführt.In the first WT 301, liquid pressurized oxygen 314 is first vaporized (or pseudo-vaporized if its pressure is supercritical) and then warmed to about ambient temperature. In countercurrent thereto, a partial flow 316 of a high-pressure air flow 315 is liquefied or pseudo-liquefied. Another partial stream 317 of the high-pressure air 315 is cooled in the heat exchanger block only to an intermediate temperature and then fed to an expansion turbine, not shown.

Der Teilstrom 306 des Luftstroms 304 dient als Ausgleichsstrom zwischen Wärmetauscherblöcken 301 und 302. Er wird bei einer Zwischentemperatur aus dem Block 302 entnommen und an einer dieser Zwischentemperatur entsprechenden Stelle des Blocks 301 in diesen eingeführt.The partial flow 306 of the air flow 304 serves as a compensating flow between heat exchanger blocks 301 and 302. It is taken from the block 302 at an intermediate temperature and introduced into the block 301 at a location corresponding to this intermediate temperature.

Bei einer ersten Anwendung der Erfindung in diesem Ausführungsbeispiel wird der "erste Teilstrom" des Patentanspruchs 1 durch den Strom 305 und der "zweite Teilstrom" durch den Strom 307 gebildet. Die Verteilung dieser beiden Luftströme auf die beiden Wärmetauscherblöcke 301 und 302 wird in Abhängigkeit einer Zwischentemperatur TIa des Wärmetauscherblocks 302 vorgenommen. Diese Zwischentemperatur Tla wird in dem Strom 306 gemessen, nachdem er den Wärmetauscherblock 302 verlassen hat und bevor er in den Wärmetauscherblock 301 eintritt. Die Temperaturmessung TIa beeinflusst dabei die Öffnung des Ventils 319.In a first application of the invention in this embodiment, the "first substream" of claim 1 is formed by the stream 305 and the "second substream" by the stream 307. The distribution of these two air streams to the two heat exchanger blocks 301 and 302 is carried out as a function of an intermediate temperature TIa of the heat exchanger block 302. This intermediate temperature Tla is measured in the stream 306 after leaving the heat exchanger block 302 and before entering the heat exchanger block 301. The temperature measurement TIa influences the opening of the valve 319.

In einer zweiten Anwendung der Erfindung wird eine Zwischentemperatur Tlb auf der Oberfläche des Wärmetauscherblocks 303 gemessen. Der "erste Teilstrom" des Patentanspruchs 1 wird dabei durch den Stickstoffstrom 311, der "zweite Teilstrom" durch den Stickstoffstrom 312 gebildet. Die Öffnung des Ventils 320 wird dabei in Abhängigkeit von der Temperatur Tlb eingestellt.In a second application of the invention, an intermediate temperature Tlb is measured on the surface of the heat exchanger block 303. The "first partial flow" of patent claim 1 is formed by the nitrogen flow 311, the "second partial flow" by the nitrogen flow 312. The opening of the valve 320 is adjusted as a function of the temperature Tlb.

Claims (5)

Verfahren zur Regelung eines gekoppelten Wärmetauscher-Systems, das einen ersten Wärmetauscherblock (1) und einen zweiten Wärmetauscherblock (2) aufweist, wobei - ein erster Fluidstrom (3) stromaufwärts des Wärmetauscher-Systems in einen ersten Teilstrom (4) und einen zweiten Teilstrom (5) aufgeteilt wird, - der erste Teilstrom (4) durch den ersten Wärmetauscherblock (1) und der zweite Teilstrom (5) durch den zweiten Wärmetauscherblock (2) geleitet wird, - ein zweiter Fluidstrom (6) im Gegenstrom zu dem ersten Teilstrom (4) durch den ersten Wärmetauscherblock (1) geleitet wird und - ein dritter Fluidstrom (7) im Gegenstrom zu dem zweiten Teilstrom (5) durch den zweiten Wärmetauscherblock (2) geleitet wird,
dadurch gekennzeichnet, dass - an einem der beiden Wärmetauscherblöcke (1, 2) zwischen dem warmen und dem kalten Ende eine erste Zwischentemperatur (TI) gemessen wird und - in Abhängigkeit vom aktuellen Wert dieser ersten Zwischentemperatur (TI) eingestellt wird, welcher Teil des ersten Fluidstroms (3) in den ersten Teilstrom (4) geht und welcher in den zweiten Teilstrom (5). A method of controlling a coupled heat exchanger system comprising a first heat exchanger block (1) and a second heat exchanger block (2), wherein a first fluid stream (3) upstream of the heat exchanger system is divided into a first partial flow (4) and a second partial flow (5), - the first partial flow (4) through the first heat exchanger block (1) and the second partial flow (5) through the second heat exchanger block (2) is passed, - A second fluid stream (6) in countercurrent to the first partial flow (4) through the first heat exchanger block (1) is passed and - A third fluid stream (7) in countercurrent to the second partial flow (5) through the second heat exchanger block (2) is passed,
characterized in that - Is measured at one of the two heat exchanger blocks (1, 2) between the hot and the cold end, a first intermediate temperature (TI) and - Is set in response to the current value of this first intermediate temperature (TI), which part of the first fluid flow (3) in the first partial flow (4) and which in the second partial flow (5). Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass eine erste Massenstrom-Stelleinrichtung (14) in der Leitung des ersten Teilstroms (4) stromaufwärts oder stromabwärts des Wärmetauscher-Systems angeordnet ist, eine zweite Massenstrom-Stelleinrichtung (13) in der Leitung des zweiten Teilstroms (5) stromaufwärts oder stromabwärts des Wärmetauscher-Systems angeordnet ist und eine (13) dieser beiden Massenstrom-Stelleinrichtungen (13, 14) als Regelventil ausgebildet ist und in Abhängigkeit vom aktuellen Wert der ersten Zwischentemperatur (TI) eingestellt wird.A method according to claim 1, characterized in that a first mass flow actuator (14) in the line of the first partial flow (4) upstream or downstream of the heat exchanger system is arranged, a second mass flow control device (13) in the line of the second partial flow (5) is arranged upstream or downstream of the heat exchanger system and one (13) of these two mass flow control devices (13, 14) is designed as a control valve and is adjusted in dependence on the current value of the first intermediate temperature (TI). Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass der erste Fluidstrom (3) in dem Wärmetauscher-System abgekühlt wird und der zweite und der dritte Fluidstrom (6, 7) in dem Wärmetauscher-System angewärmt werden.A method according to claim 1 or 2, characterized in that the first fluid stream (3) is cooled in the heat exchanger system and the second and third fluid streams (6, 7) are heated in the heat exchanger system. Verfahren nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet, dass der erste Fluidstrom in dem Wärmetauscher-System angewärmt wird und der zweite und der dritte Fluidstrom in dem Wärmetauscher-System abgekühlt werden.Method according to one of claims 1 or 2, characterized in that the first fluid flow is warmed in the heat exchanger system and the second and the third fluid flow are cooled in the heat exchanger system. Verfahren nach einem der Anspruch 3, dadurch gekennzeichnet, dass - der zweite und der dritte Fluidstrom (301, 303) durch Teilströme eines vierten Fluidstroms (310) gebildet werden, - an demjenigen der beiden Wärmetauscherblöcke (311, 312), an dem nicht die erste Zwischentemperatur (TIb) gemessen wird, zwischen dem warmen und dem kalten Ende eine zweite Zwischentemperatur (Tla) gemessen wird und - in Abhängigkeit vom aktuellen Wert dieser zweiten Zwischentemperatur (Tla) eingestellt wird, welcher Teil des vierten Fluidstroms (310) in den zweiten Fluidstrom (311) geht und welcher in den dritten Fluidstrom (312). Method according to one of the claims 3, characterized in that the second and third fluid streams (301, 303) are formed by partial streams of a fourth fluid stream (310), - at the one of the two heat exchanger blocks (311, 312), at which not the first intermediate temperature (TIb) is measured, between the hot and the cold end, a second intermediate temperature (Tla) is measured, and - Is set in response to the current value of this second intermediate temperature (Tla), which part of the fourth fluid stream (310) in the second fluid stream (311) and which in the third fluid stream (312).
EP14003476.0A 2014-10-09 2014-10-09 Method for regulating a coupled heat exchanger system and heat exchanger system Withdrawn EP3006875A1 (en)

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EP14003476.0A EP3006875A1 (en) 2014-10-09 2014-10-09 Method for regulating a coupled heat exchanger system and heat exchanger system
EA201790797A EA201790797A1 (en) 2014-10-09 2015-10-08 METHOD OF ADJUSTMENT OF DIFFERENT HEAT EXCHANGE SYSTEM AND HEAT EXCHANGE SYSTEM
CN201580054538.3A CN106796081B (en) 2014-10-09 2015-10-08 Method for controlling a coupled heat exchanger system and heat exchanger system
KR1020177012429A KR20170066595A (en) 2014-10-09 2015-10-08 Method for controlling a coupled heat exchanger system and heat-exchanger system
EP15781577.0A EP3204704A1 (en) 2014-10-09 2015-10-08 Method for controlling a coupled heat exchanger system and heat-exchanger system
US15/513,167 US10345040B2 (en) 2014-10-09 2015-10-08 Method for controlling a coupled heat exchanger system and heat exchanger system
PCT/EP2015/001980 WO2016055162A1 (en) 2014-10-09 2015-10-08 Method for controlling a coupled heat exchanger system and heat-exchanger system

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CN106796081B (en) 2019-12-17
KR20170066595A (en) 2017-06-14
US20170314852A1 (en) 2017-11-02
EP3204704A1 (en) 2017-08-16
US10345040B2 (en) 2019-07-09

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