EP1059488A2 - Process and installation for heating a liquid medium - Google Patents

Abstract

The fluid medium to be heated passes through an initial heating system (2,3) and at least one following heating system (5,6). Each heating system has heat exchangers (2,5) in contact with the medium flow, with higher temp. levels at the second system (5,6) than in the first (2,3). The direct medium flow into the first heating system (2,3) is reduced, to accelerate the increase in temp. and, in extreme cases, is stopped, and the medium within the first system (2,3) is recirculated. The medium can be fed directly to the second heating system (5,6), with medium recirculation in the first system (2,3) or a combined recirculation in both systems (2,3;5,6).

Description

Technical field

The present invention relates to a method for heating a liquid medium using a first and at least one following this second thermal system, which thermal systems each at least one heat exchanger through which the medium flows and which second system on a higher one Temperature level than the first one is operated. It affects a system for carrying out the process, including a feed line for supplying the medium to be heated.

State of the art

Plants in which one liquid medium has several undergoes thermal systems to be heated, if necessary are to be evaporated, for example, in boilers available, which is caused by flue gas from burners or Exhaust gas from gas turbines are heated.

The medium can be water with optional additives his. The water becomes dependent on the end user heated to a predetermined temperature in the boiler for example an industrial plant, a hot water network, etc. to be supplied or evaporated, for example a steam turbine or an industrial one Steam consumers to be fed.

The first thermal system in one Boiler, which is a first heat exchanger, a heating surface bundle is usually called economizer. The one for preheating the feed water in the boiler The intended economizer works due to the temperature conditions preferably on the flue gas or flue gas side End of the boiler, d. H. at comparative low temperatures.

On the other hand, the temperature difference between the smoke or exhaust gas and the one to be heated Feed water relatively low. This in turn has big ones Heating surfaces and associated large heating surface masses result.

Consequently, an economizer needs to be adjusted the temperature, for example, when the operational changes Conditions for a long period. Further exists due to the temperatures prevailing in the economizer and, as is known, press the risk of dew point corrosion.

• die Rezirkulation und
• die Bypassung des Economizers.

Known methods for raising the feed water temperature at the boiler inlet or for avoiding dew point corrosion at the flue gas end of the boiler are dependent, for example, on the fuel used

• recirculation and
• bypassing the economizer.

During recirculation, the feed water Pre-warmed water mixed in at the boiler inlet. At the Bypassing the economizer is bypassed by the feed water and preheating at a higher temperature level working system for example a steam generating System at the expense of reducing steam generation performed.

In particular when starting off or at a Change the heating surfaces to a sulfur-containing fuel measures are not to be damaged, which go beyond the above, d. H. one clearly faster temperature increase in the economizer area enable.

Presentation of the invention

The invention is therefore based on the object a method for heating a liquid medium by means of a first and a second following this thermal system with a higher temperature level to create, according to which under special operating conditions (Start-up, fuel change) an accelerated Raising the temperature of the first thermal system is made possible. Furthermore, the danger of dew point corrosion is said can be reduced.

This is achieved according to the invention that for accelerated increase in the temperature of the medium in the first thermal system to supply the medium directly the same reduced and in extreme cases prevented, and that the medium flowing through the first thermal system is circulated.

A system for performing the inventive The process is characterized in that the first thermal system using a first heat exchanger an inlet pipe connected to the feed pipe and an outlet line, which via a line section runs to the second thermal system, has, wherein between the feed line and the inlet line a first control element is arranged, that of the feed line one with a second control element Equipped bypass line to the outlet line that runs from the outlet line a line section to the second thermal system, and that the outlet line with a recirculation line a third control element and a first pump with the Inlet line is connected to which recirculation line arranged parallel to the first heat exchanger is.

Advantageous embodiments of the invention are described in the subclaims.

Brief description of the drawing

Figur 1 zeigt eine Kreislaufanordnung gemäss einer ersten Ausführung der Erfindung mit einem Trommel-Umlauf-Verdampfer als zweites thermisches System,

Figur 2 zeigt eine Kreislaufanordnung gleich derjenigen der Figur 1, jedoch mit einem Zwangsdurchlaufverdampfer als zweites thermisches System,

Figur 3 zeigt eine Kreislaufanordnung gemäss einer zweiten Ausführung der Erfindung, mit einem Trommel-Umlauf-Verdampfer als zweites thermisches System,

Figur 4 zeigt eine Kreislaufanordnung gemäss einer dritten Ausführung der Erfindung, mit einer zweiten Vorwärmstufe mit Behälter als zweites thermisches System,

Figur 5 zeigt eine Kreislaufanordnung gemäss einer vierten Ausführung der Erfindung, mit einem Zwangsdurchlaufverdampfer als zweites thermisches System,

Figur 6 zeigt eine Kreislaufanordnung gemäss einer fünften Ausführung der Erfindung, mit einer zweiten Vorwärmstufe mit Behälter als zweites thermisches System,

Figur 7 zeigt eine Kreislaufanordnung gemäss einer sechsten Ausführung der Erfindung, mit einem Trommel-Umlauf-Verdampfer als zweites thermisches System,

Figur 8 zeigt eine Kreislaufanordnung gemäss einer siebenten Ausführung der Erfindung, mit einer zweiten Vorwärmstufe mit Behälter als zweites thermisches System und

Figur 9 zeigt eine Kreislaufanordnung gemäss einer achten Ausführung der Erfindung, mit einem Trommel-Umlauf-Verdampfer als zweites thermisches System.

Various arrangements of circuits for explaining various embodiments of the invention are shown in simplified form in the drawing figures. Only the elements essential for understanding the invention are shown.

FIG. 1 shows a circuit arrangement according to a first embodiment of the invention with a rotary drum evaporator as the second thermal system,

FIG. 2 shows a circuit arrangement similar to that of FIG. 1, but with a forced flow evaporator as the second thermal system,

FIG. 3 shows a circuit arrangement according to a second embodiment of the invention, with a rotary drum evaporator as the second thermal system,

FIG. 4 shows a circuit arrangement according to a third embodiment of the invention, with a second preheating stage with a container as the second thermal system,

FIG. 5 shows a circuit arrangement according to a fourth embodiment of the invention, with a once-through evaporator as the second thermal system,

FIG. 6 shows a circuit arrangement according to a fifth embodiment of the invention, with a second preheating stage with a container as the second thermal system,

FIG. 7 shows a circuit arrangement according to a sixth embodiment of the invention, with a rotary drum evaporator as the second thermal system,

FIG. 8 shows a circuit arrangement according to a seventh embodiment of the invention, with a second preheating stage with a container as the second thermal system and

FIG. 9 shows a circuit arrangement according to an eighth embodiment of the invention, with a drum circulation evaporator as the second thermal system.

Ways of Carrying Out the Invention

As an embodiment to explain the invention a section of a boiler is used. This Section is said to be a first thermal system and a have second thermal system, the second thermal system at a higher temperature level than the first thermal system is operated.

Specifically included in the examples shown Finishes the first thermal system the economizer and the second thermal system the evaporator of the boiler. For the idea of the invention, it is immaterial whether the vaporizer is a rotary drum vaporizer or a once-through evaporator is like out the examples described below.

Show other examples a second preheating stage as the second thermal system with container on.

The following figures, procedures and explanations build on each other in principle.

It is now on the first execution according to the figure 1 with a rotary drum evaporator as the second thermal system referenced. The reference number 1 denotes the feed water pipe through which the to be heated Medium, i.e. treated feed water, supplied becomes. The feed water is supplied by the feed water pump 31 promoted to the boiler. The feed water line 1 ends for a first control element 10. After the first control element 10 runs an inlet line 3 to a first Heat exchanger 2 (the economizer) by an outlet pipe 4 followed. The line section 9 leads to the second as an extension of the outlet line 4 thermal system, in the specific case to the steam drum 6.

Before the first control element 10 branches from the Feed water line 1 a bypass line 8 with a second control element 11 to the outlet line 4.

A recirculation line 7 with a first Pump 13 and a third control element 12 extends between the outlet line 4 and the inlet line 3, wherein it can be seen from the drawing figure that the first pump 13 for delivery from the discharge line 4 is arranged to the inlet line 3. After Branch of the recirculation line 7 from the outlet line 4 is a fourth in the outlet line 4 Control element 14 arranged.

The second thermal system includes one second heat exchanger 5, the example evaporator, the one with a container for holding a lot of the medium in the liquid state, here specifically with a steam drum 6 communicates. From the steam drum 6 runs a flow line 15 to the second heat exchanger 5. A return line runs from the second heat exchanger 5 16 to the steam drum 6. The reference number 32 denotes an outlet line of the steam drum 6, for example to a steam consumer, a steam turbine, a superheater, etc.

The two heat exchangers 2.5 are replaced by one Heating gas 56 heated, which in the case of a burner fired boiler flue gas or in the case of waste heat utilization a gas turbine can be exhaust gas.

The heating of the heat exchanger 2.5 is at identical to all of the exemplary embodiments and thus becomes not explained repeatedly.

In normal operation of the two thermal systems are the first control element 10 and the fourth control element 14 open and the second control element 11 and that third control element 12 closed. Next is the first Pump 13 out of operation.

That in the direction of arrow 33 through the Feed water line 1 flowing water thus flows through the inlet line 3 to the first heat exchanger 2, the economizer, from this through the outlet line 4 and their extension the line section 9 in the Steam drum 6 or alternatively into the feed line 15, as indicated by the dashed arrow 38.

The water flows from the steam drum 6 through the flow line 15 to the second heat exchanger 5, the evaporator, and the steam or the water-steam mixture flows from the second heat exchanger 5 through the Return line 16 back to the steam drum 6. In the Steam drum 6 is the separation of water and Steam. Finally, the steam flows through the outlet line 32 to a consumer.

The circulation in the second thermal System can by natural flow, by a pump or a combination of both options.

To accelerate the temperature in the first heat exchanger 2, for example when starting the Appendix, the first control element 10 and the fourth Control element 14 at least partially, in an extreme case completely closed. The second control element 11 and that third control element 12 are at least partially, in In extreme cases fully opened. The pump 13 is in operation.

Thus, the water to be heated flows in Circulation, in the extreme case with completely closed or open control elements in a completely closed one Circuit, in the direction of arrow 34 from cold end to the warm end of the first heat exchanger 2, through the outlet line 4 to the recirculation line 7, flows in the direction of arrow 35 through the same, then to inlet line 3 and finally back to the cold one End of the first heat exchanger 2.

Consequently, the cold end of the heat exchanger 2 not constantly new and therefore "cold" feed water fed via the feed water line 1, but already flowing from the warm end of the heat exchanger 2 heated water. This leads to faster heating not only the water, but also the heating surface mass the first heat exchanger 2.

Since the control elements 10, 14 are closed and the control element 11 of the bypass line 8 in the open position the water flows from the feed water pipe 1 in the direction of arrow 36 through the bypass line 8 and the line section 9 to the second thermal system.

Two variants are possible:

As indicated by arrow 37, this can Water via line section 9 directly into the steam drum 6 stream.

As indicated by the dashed arrow 38 is a flow of water over the line section 9 in the flow line 15.

For the sake of clarity, any the flow variants according to arrows 37 or 38 associated fittings not shown.

It should be noted that the respective control elements not necessarily in a completely closed one or must be in a fully open position. There are intermediate positions also possible to get the best possible To achieve effect. There are also regulated movements of one position in the other position, for example to avoid thermal shocks.

The embodiment shown in Figure 2 is regarding the first thermal system identical to the exemplary embodiment according to FIG. 1.

The second thermal system is a once-through evaporator consisting of the second heat exchanger the evaporator 5, which is connected to the evaporator 5 standing supply line 15 and return line 16 and a separator 6A.

The flow through the second thermal system is different from that shown in Figure 1 Variant of a drum circulation evaporator through the line section 9 in the flow line 15, in the direction arrow 39 through the evaporator 5 and via the return line 16 in the separator 6A.

The separation of takes place in the separator 6A Water and steam. The steam flows through the outlet line 32 to a steam consumer or superheater. About the flow line 15 with the circulation pump 40 is in Separator separated water returned to the evaporator 5.

Operation of the first thermal system is now in normal operation as well as in operation accelerated temperature increase completely identical to that according to FIG. 1.

A second embodiment of the invention described below with reference to FIG. 3, as a variant, again a rotary drum evaporator with the steam drum 6 as a second thermal System is used. As far as possible, the the same reference numerals are used as in Figures 1 and 2nd

The feed water line 1 with the feed water pump 31, through which the feed water towards of arrow 33 flows to the first thermal System that in particular a first heat exchanger 2 with an inlet line 3, an outlet line 4, a first control element 10, a fourth control element 14 and a recirculation line 7 with a first Pump 13 and a third control element 12.

A bypass line branches from the feed water line 1 8 with a second control element 11, which Bypass line 8 runs to outlet line 4. The Line section 9 leads as an extension of the outlet line 4 to the second thermal system, specifically Fall to the steam drum 6. The second thermal system has in particular a steam drum 6 with an outlet line 32 and a second heat exchanger 5, the via a flow line 15 and a return line 16 is connected to the steam drum 6.

The difference between this second version according to Figure 3 and the execution according to the figures 1 and 2 lies in the arrangement of the pump 13 in the recirculation line 7.

For accelerating the temperature in the first heat exchanger 2, for example when starting the Appendix, the first control element 10 and the fourth Control element 14 at least partially, in an extreme case completely closed. The second control element 11 and that third control element 12 are at least partially, in In extreme cases fully opened and the pump 13 in operation set.

In this version, what is to be heated flows Water in the circuit in the direction of arrow 43 from warm end to the cold end of the first heat exchanger 2, through the inlet line 3 to the recirculation line 7, flows through it in the direction of arrow 42, thereafter to outlet line 4 and finally back to the warm one End of the first heat exchanger 2.

The flow in the second thermal system according to FIG. 3, the flow in the second takes place thermal system of the embodiment according to FIG. 1.

Figure 4 shows a third embodiment, wherein as a variant for the second thermal system a second preheating stage with a second heat exchanger 5 and used with container 6. It was like this the same reference numerals as possible for the previous versions selected.

The feed water line 1 with the feed water pump 31, through which the feed water towards of arrow 33 flows to the first thermal System that in particular a first heat exchanger 2 with an inlet line 3, an outlet line 4, a first control element 10, a fourth control element 14 and a recirculation line 7 with a first Pump 13 and a third control element 12.

A bypass line branches from the feed water line 1 8 with a second control element 11, which Bypass line 8 runs to outlet line 4. The Line section 9 leads as an extension of the outlet line 4 to the second thermal system, specifically Case to tank 6. The second thermal system points in particular a container 6 with an outlet line 32 and a second heat exchanger 5, which has a Flow line 15 and a return line 16 with the container 6 communicates.

That via the line section 9 in the direction of the arrow 37 feed water flowing into the container 6 can alternatively flow into the flow line 15, as indicated by the dashed arrow 38.

This version runs from the second Heat exchanger 5 a line 17 with a pump 18 and a control element 19 for the warm end of the first heat exchanger 2 or to the outlet line 4.

According to a second variant, the dashed lines is drawn, branches from the flow line 15 a line 41 which merges into line 17.

For accelerating the temperature in the first heat exchanger 2, for example when starting the Appendix, are the first control element 10, the second control element 11 and the control element 19 in the open position. The third control element 12 and the fourth control element 14 are in the closed position. The first pump 13 in the recirculation line 7 is out of operation.

That through the feed water line 1 in the direction of the arrow 33 flowing feed water flows through the bypass line 8 in the direction of arrow 36 and the line section 9 directly into the second thermal System, either in container 6, as indicated by arrow 37 is shown, or alternatively into the flow line 15, as drawn with the dashed arrow 38.

The water flows from the second heat exchanger 5 in the direction of arrow 51 through line 17 into the Outlet line 4 and to the warm end of the first heat exchanger 2. The water continues to flow towards the Arrow 51 from the warm to the cold end of the first heat exchanger 2 and then to the inlet pipe 3.

At the end of the inlet line 3, this becomes Water flow, as shown by arrow 44, with the flowing through the feed water line 1 feed water flow mixed, whereupon both water flows together through the bypass line 8 and the line section 9 to second thermal system, i.e. to container 6 or Flow supply line 15. This will make both thermal Systems formed comprehensive cycle.

According to the second variant, water can escape the flow line 15 via line 41 into the line 17 stream.

It is now also possible to build the system according to the figure 4 to drive according to the system of Figure 1 by the Control elements 10, 14, 19 closed, control elements 11 and 12 opened, the first pump 13 started up and the pump 18 is out of order.

That means that with this execution it is possible to start in two phases, namely during a first phase according to the one with the arrangement 1 possible method and during a second phase according to the one previously described Arrangement according to FIG. 4 possible methods or vice versa.

This is to illustrate that the described embodiments of course can also be used in any combination.

Figure 5 shows a circuit arrangement according to a fourth embodiment of the invention. This arrangement points according to the embodiment Figure 2 as a second thermal system, a once-through evaporator on.

The feed water line 1 with the feed water pump 31, through which the feed water towards of arrow 33 flows to the first thermal System similar to the first thermal described above Systems is formed and in particular a first Heat exchanger 2 with an inlet line 3, one Outlet line 4, a first control element 10, a fourth Control element 14 and a recirculation line 7 with a first pump 13 and a third control element 12 having.

A bypass line branches from the feed water line 1 8 with a second control element 11, which Bypass line 8 runs to outlet line 4. The Line section 9 leads as an extension of the outlet line 4 to the second thermal system, specifically Flow line 15 case. The second thermal system In particular, the evaporator has a second heat exchanger 5, on a feed line 15 with feed water is applied and via the return line 16 is connected to the separator 6A.

The flow through the second thermal system takes place through the line section 9 into the flow line 15, in the direction of arrow 39 through the evaporator 5 and via the return line 16 into the separator 6A.

The separation of takes place in the separator 6A Water and steam. The steam flows through the outlet line 32 to a steam consumer or superheater. About the flow line 15 with the circulation pump 40 is in Separator separated water returned to the evaporator 5.

A line 20 runs from the separator 6A a further pump 21 and a further control element 22 to the outlet line 4, in particular to the warm end the first heat exchanger 2.

For accelerating the temperature in the first heat exchanger 2, for example when starting the Appendix, the third control element 12 and the fourth Control element 14 closed. The first pump 13 in the Recirculation line 7 is not in operation.

The first control element 10 in the inlet line 3, the second control element 11 in the bypass line 8 and the control element 22 in the line 20 are in the open position, the pump 21 is in operation.

Thus, the feed water flows from the feed water line 1 through the bypass line 8 and the line section 9 in the direction of arrow 36 in the flow line 15 and thus to the second thermal system.

Water now flows from the separator 6A in the direction arrow 46 through line 20 to the outlet line 4, i.e. to the warm end of the first heat exchanger 2. The water continues to flow in the direction of arrow 43 through the first heat exchanger 2 to its cold end, then in the direction of arrow 44 through the inlet duct 3 to the bypass line 8 to together with feed water to flow back to the second thermal system.

According to this version, there is therefore a circuit comprising both thermal systems.

Figure 6 shows a fifth embodiment, wherein as a variant for the second thermal system a second preheating stage with a second heat exchanger 5 and is used with a container 6.

The feed water line 1 with the feed water pump 31, through which the feed water towards of arrow 33 flows to the first thermal System that in particular a first heat exchanger 2 with an inlet line 3, an outlet line 4, a first control element 10 and a recirculation line 7 with a first pump 13 and a third Has control element 12.

A bypass line branches from the feed water line 1 8 with a second control element 11, which Bypass line 8 runs to outlet line 4. On Line section 9 leads as an extension of the outlet line 4 to the second thermal system, specifically Case to tank 6. The second thermal system points in particular a container 6 with an outlet line 32 and a second heat exchanger 5, which has a Flow line 15 and a return line 16 with the container 6 communicates.

That via the line section 9 in the direction of the arrow 37 feed water flowing into the container 6 can alternatively flow into the flow line 15, as indicated by the dashed arrow 38.

This version runs from the second Heat exchanger 5 a line 23 with a pump 24 and a control element 25 to the cold end of the first heat exchanger 2 or to the inlet line 3.

For accelerating the temperature in the first heat exchanger 2, for example when starting the The first control element 10 and the third control element are attached 12 in the closed position and the first pump 13 out of service. The second control element 11 and the control element 25 are in the open position and the pump 24 is in operation.

The water flows in this version Direction of arrow 51, through line 23, further in Direction of arrows 47, 34 and 48 through the first heat exchanger 2 and then together with the one via the feed water line 1 and the bypass line 8 inflow Feed water via line section 9 according to a first variant in the direction of arrow 37 in the container 6 or according to a second variant in the direction of dashed arrow 38 in the flow line 15.

FIG. 7 shows a circuit arrangement according to a sixth embodiment of the invention with a Rotary drum evaporator with the steam drum 6 as second thermal system.

The feed water line 1 with the feed water pump 31, through which the feed water towards of arrow 33 flows to the first thermal System that in particular a first heat exchanger 2 with an inlet line 3, an outlet line 4, a first control element 10 and a recirculation line 7 with a first pump 13 and a third Has control element 12.

A bypass line branches from the feed water line 1 8 with a second control element 11, which Bypass line 8 runs to outlet line 4. On Line section 9 leads as an extension of the outlet line 4 to the second thermal system, specifically Fall to the steam drum 6. The second thermal system has in particular a steam drum 6 with an outlet line 32 and a second heat exchanger 5, the via a flow line 15 and a return line 16 is connected to the steam drum 6.

That via the line section 9 in the direction of the arrow 37 feed water flowing into the steam drum 6 can alternatively flow into the flow line 15, as indicated by the dashed arrow 38.

According to a first variant, the Steam drum 6 a line 26 with a pump 27 and a Control element 28 to the cold end of the first heat exchanger 2 or to the inlet line 3.

According to a second variant, the dashed lines is drawn, branches from the flow line 15 a line 45 which merges into line 26.

For accelerating the temperature in the first heat exchanger 2, for example when starting the Appendix, the first control element 10 and the third control element 12 closed. The first pump 13 in the recirculation line 7 is out of order.

The second control element 11 in the bypass line 8 and the control element 28 in the line 26 are in the open position, the pump 27 is in operation.

Thus, the feed water flows from the feed water line 1 through the bypass line 8 and the line section 9 in the direction of arrows 36 and 37 in the Steam drum 6 or alternatively into the feed line 15, as indicated by the dashed arrow 38.

Water now flows in from the steam drum 6 Direction of arrow 46 through line 26 to the pump 27 and the control element 28 to the inlet line 3, i.e. to the cold end of the first heat exchanger 2, in Direction of arrows 47,34 to the warm end of the first heat exchanger 2 and through the outlet line 4 in the direction the arrow 48 to the line section 9 to together with the directly flowing feed water to the steam drum 6 or to flow into the flow line 15.

According to the second variant, water can escape the flow line 15 via line 45 into the line 26 stream.

According to this version, there is therefore a circuit comprising both thermal systems.

FIG. 8 shows a circuit arrangement according to a seventh embodiment of the invention, wherein as Design variant for the second thermal system second preheating stage with a second heat exchanger 5 and is used with container 6.

The feed water line 1 with the feed water pump 31, through which the feed water towards of arrow 33 flows to the first thermal System that in particular a first heat exchanger 2 with an inlet line 3, an outlet line 4, a first control element 10 and a recirculation line 7 with a first pump 13 and a third Has control element 12.

Another is in the recirculation line 7 Control element 49 arranged.

A bypass line branches from the feed water line 1 8 with a second control element 11, which Bypass line 8 runs to outlet line 4. The Line section 9 leads as an extension of the outlet line 4 to the second thermal system, specifically Case to tank 6. The second thermal system points in particular a container 6 with an outlet line 32 and a second heat exchanger 5, which has a Flow line 15 and a return line 16 with the container 6 communicates.

That via the line section 9 in the direction of the arrow 37 feed water flowing into the container 6 can alternatively flow into the flow line 15, as indicated by the dashed arrow 38.

In this embodiment, a line 29 branches from the second heat exchanger 5, in which a control element 50 is inserted, which line 29 at one point between the control element 49 and the first pump 13 in the recirculation line 7 opens.

For accelerating the temperature in the first heat exchanger 2, for example when starting the Appendix, are the first control element 10 and the control element 49 closed. The control elements 11, 12 and 50 are in the open position, the first pump 13 is in operation set.

Thus, the feed water flows from the feed water line 1 through the bypass line 8 and the line section 9 in the direction of arrows 36 and 37 in the Steam drum 6 or alternatively into the feed line 15, as indicated by the dashed arrow 38.

Water now flows from the second heat exchanger 5 in the direction of arrow 51 through line 29 into the Recirculation line 7 and in the direction of arrow 52 to inlet line 3, the cold end of the first heat exchanger 2, through the first heat exchanger 2 to the outlet line 4, the warm end of the first heat exchanger 2, to line section 9 and together with the feed water flowing directly through the bypass line 8 according to arrow 37 in container 6 or alternatively according to the dashed arrow 38 in the flow line 15.

The direction of flow is with arrows 47, 34 and 48 shown by the first heat exchanger 2.

FIG. 9 shows a circuit arrangement according to an eighth embodiment of the invention with a Rotary drum evaporator with the steam drum 6 as second thermal system.

The feed water line 1 with the feed water pump 31, through which the feed water towards of arrow 33 flows to the first thermal System that in particular a first heat exchanger 2 with an inlet line 3, an outlet line 4, a first control element 10 and a recirculation line 7 with a first pump 13 and a third Has control element 12.

Another is in the recirculation line 7 Control element 49 arranged.

A bypass line branches from the feed water line 1 8 with a second control element 11, which Bypass line 8 runs to outlet line 4. On Line section 9 leads as an extension of the outlet line 4 to the second thermal system, specifically Fall to the steam drum 6. The second thermal system has in particular a steam drum 6 with an outlet line 32 and a second heat exchanger 5, the via a flow line 15 and a return line 16 is connected to the steam drum 6.

That via the line section 9 in the direction of the arrow 37 feed water flowing into the steam drum 6 can alternatively flow into the flow line 15, as indicated by the dashed arrow 38.

According to a first variant, the Steam drum 6 a line 54 in which a control element 55 is used for recirculation line 7 and opens at a point between the other control element 49 and the first pump 13 in the recirculation line 7.

According to a second variant, the dashed lines is drawn, branches from the flow line 15 a line 30 which merges into line 54.

For accelerating the temperature in the first heat exchanger 2, for example when starting the The system is the first control element 10 and the control element 49 closed. The control elements 11, 12 and 55 are in the open position, the first pump 13 is started.

Thus, the feed water flows from the feed water line 1 through the bypass line 8 and the line section 9 in the direction of arrows 36 and 37 in the Steam drum 6 or alternatively into the feed line 15, as indicated by the dashed arrow 38.

Water now flows in from the steam drum 6 Direction of arrow 53 through line 54 into the recirculation line 7 and in the direction of arrow 52 Inlet line 3, the cold end of the first heat exchanger 2, through the first heat exchanger 2 to the outlet line 4, the warm end of the first heat exchanger 2, to line section 9 and together with that by Bypass line 8 directly flowing feed water according to arrow 37 in the steam drum 6 or alternatively according to the dashed arrow 38 in the flow line 15.

According to the second variant, water can escape the flow line 15 via line 30 into the line 54 stream.

The direction of flow is with arrows 47, 34 and 48 shown by the first heat exchanger 2.

Of course, those are described Procedures also in any combination and time Sequences can be used.

In principle, the invention is independent of the concrete design, construction, construction u. the like of the elements and systems described.

Reference list

1

Feed line, feed water line

2nd

First heat exchanger / economizer

3rd

Inlet line to item 2

4th

Outlet line from item 2

5

Second heat exchanger / evaporator

6, 6A

Container (steam drum 6; separator 6A)

7

Recirculation line

8th

Bypass line

9

Line section from item 4

10th

First control element, between items 1 and 3

11

Second control element, in item 8

12th

Third control element, in item 7

13

First pump, in pos. 7

14

Fourth control element, in item 4

15

Supply line

16

Return line

17th

Line, from item 5 to item 4

18th

Pump, in item 17

19th

Control element, in item 17

20th

Management, from pos. 6 to POS. 4th

21

Another pump, in item 20

22

Another control element, in item 20

23

Line, from item 5 to item 3

24th

Pump, in item 23

25th

Control element, in item 23

26

Line, from item 6 to item 3

27

Pump, in item 26

28

Control element, in item 26

29

management

30th

management

31

Feed water pump

32

Outlet pipe

33

arrow

34

arrow

35

arrow

36

arrow

37

arrow

38

arrow

39

arrow

40

Circulation pump

41

management

43

arrow

44

arrow

45

management

46

arrow

47

arrow

48

arrow

49

Control element

50

Control element

51

arrow

52

arrow

53

arrow

54

management

55

Control element

56

Heating gas (flue gas, exhaust gas)

Claims (33)

Process for heating a liquid medium by means of a first (2,3,4,7,12,13) and at least a second thermal system following this (5,6,6A, 15,16), which thermal systems each at least a heat exchanger (2.5) through which the medium flows and which second thermal system (5,6,6A, 15, 16) at a higher temperature level than the first (2,3,4,7,12,13) is operated, characterized in that that to accelerate the temperature of the medium in the first thermal system (2,3,4,7,12,13) the direct one Supply of the medium to the same reduced and in Extreme case prevented, and that the first thermal system (2,3,4,7,12,13) flowing medium circulated becomes. A method according to claim 1, characterized in that the thermal systems (2,3,4,7,12, 13; 5,6,6A, 15,16) inflowing medium to be heated to Part and in extreme cases completely directly the second thermal system (5,6,6A, 15,16) is supplied. A method according to claim 1, characterized in that the medium is only in the first thermal System (2,3,4,7,12,13) is recycled. A method according to claim 1, characterized in that the medium in the first (2,3,4,7,12,13) and combined in the second thermal system (5,6,6A, 15,16) is circulated. A method according to claim 1, characterized in that the medium in the first thermal system (2,3,4,7,12,13) from the cold end of its heat exchanger (2) is circulated to its warm end. A method according to claim 1, characterized in that the medium in the first thermal system (2,3,4,7,12,13) from the warm end of its first heat exchanger (2) is circulated to the cold end thereof. A method according to claim 4, characterized in that the medium from the second thermal system (5,6,6A, 15,16) to the first thermal system (2,3,4,7,12, 13) and back to the second thermal system (5,6,6A, 15, 16) is circulated and a direct supply of the Medium for the second thermal system (5,6,6A, 15,16) created that the first thermal system (2,3, 4,7,12,13) outflowing medium with the second thermal System (5,6,6A, 15,16) directly flowing medium together the second thermal system (5,6,6A, 15, 16) is supplied and an excess amount of the medium removed from the second thermal system (5,6,6A, 15,16) becomes. A method according to claim 7, characterized in that the medium from the second thermal system (5,6,6A, 15,16) the warm end of the first heat exchanger (2) of the first thermal system (2,3,4,7,12,13) fed becomes. A method according to claim 8, characterized in that the medium from the second heat exchanger (5) of the second thermal system (5,6,6A, 15,16) the warm one End of the first heat exchanger (2) of the first thermal Systems (2,3,4,7,12,13) is fed. The method of claim 8, wherein the second thermal system (5,6,6A, 15,16) a container (6.6A) to hold an amount of the medium in one has liquid state, characterized in that the medium from the container (6.6A) of the second thermal Systems (5,6,6A, 15,16) the warm end of the first heat exchanger (2) of the first thermal system (2,3,4,7, 12, 13) is supplied. A method according to claim 7, characterized in that the medium from the second thermal system (5,6,6A, 15,16) the cold end of the first heat exchanger (2) of the first thermal system (2,3,4,7,12,13) is fed. A method according to claim 11, characterized in that the medium from the second heat exchanger (5) of the second thermal system (5,6,6A, 15,16) dem cold end of the first heat exchanger (2) of the first thermal system (2,3,4,7,12,13) is supplied. The method of claim 11, wherein the second thermal system (5,6,6A, 15,16) a container (6.6A) to hold an amount of the medium in one has liquid state, characterized in that the medium from the container (6.6A) of the second thermal Systems (5,6,6A, 15,16) the cold end of the first heat exchanger (2) of the first thermal system (2,3,4,7, 12, 13) is supplied. The method of claim 7, wherein the first thermal system (2,3,4,7,12,13) one from warm to cold end of his first heat exchanger (2) Recirculation line (7), characterized in that that the medium from the second thermal system (5,6, 6A, 15, 16) via the recirculation line (7) to the cold one End of the first heat exchanger (2) of the first system (2,3,4,7,12,13) is fed. A method according to claim 14, characterized in that the medium from the second heat exchanger (5) the second thermal system (5,6,6A, 15,16) of Recirculation line (7) of the first thermal system (2,3,4,7,12,13) is fed. The method of claim 14, wherein the second thermal system (5,6,6A, 15,16) a container (6.6A) to hold an amount of the medium in one has liquid state, characterized in that the medium from the container (6.6A) of the second thermal System (5,6,6A, 15,16) of the recirculation line (7) of the first thermal system (2,3,4,7,12,13) supplied becomes. Plant for carrying out the process according to claim 1, with a feed line (1) for supply of the medium to be heated, characterized in that the first thermal system (2,3,4,7,12,13) a first Heat exchanger (2) with one connected to the feed line (1) Inlet line (3) and an outlet line (4), wherein between the feed line (1) and the inlet line (3) has a first control element (10) is arranged that of the feed line (1) with a second control element (11) equipped bypass line (8) to the outlet line (4) that runs from the Outlet line (4) one line section (9) to the second thermal system (5,6,6A, 15,16) runs and that the outlet line (4) via a recirculation line (7) with a third control element (12) and a first Pump (13) in connection with the inlet line (3) which recirculation line (7) is parallel to the first Heat exchanger (2) is arranged. Installation according to claim 17, characterized in that the second thermal system (5,6,6A, 15, 6) a second heat exchanger (5) and a container (6.6A) to hold an amount of the medium in the liquid Condition, which second heat exchanger (5) over one from the tank (6,6A) to the second heat exchanger (5) running flow line (15) and one from the second heat exchanger (5) back to the tank (6.6A) Return line (16) in connection with the container (6,6A) stands. Installation according to claim 18, characterized in that after the branch of the recirculation line (7) a fourth control element from the outlet line (4) (14) arranged in the outlet line (4) is. Installation according to claim 18, characterized in that the line section (9) to the container (6.6A) of the second thermal system (5.6.6A, 15.16) runs. Installation according to claim 18, characterized in that the line section (9) in the flow line (15) opens. Installation according to claim 18, characterized in that in the flow line (15) a circulation pump (40) is arranged. Installation according to claim 17, characterized in that the arranged in the recirculation line (7) first pump (13) for conveying the medium from the outlet line (4) to the inlet line (3) is. Installation according to claim 17, characterized in that the arranged in the recirculation line (7) first pump (13) for conveying the medium from the inlet line (3) to the outlet line (4) is. Installation according to claim 18, characterized in that from the second heat exchanger (5) into the Outlet line (4) opening line (17) with an in Direction to the outlet line (4) pump (18) and a control element (19) is branched off. Installation according to claim 18, characterized in that from the container (6.6A) into the outlet line (4) opening line (20) with another pump (21) and another control element (22) branched off is. Installation according to claim 18, characterized in that from the supply line (15) into the Outlet line (4) opening line (41, 17) with a pump in the direction of the outlet line (4) (18) and a control element (19) is branched off. Installation according to claim 18, characterized in that from the second heat exchanger (5) into the Inlet line (3) opening line (23) with a Pump (24) conveying to the inlet line (3) and a control element (25) is branched off. Installation according to claim 18, characterized in that from the container (6.6A) into the inlet pipe (3) opening line (26) with one in the direction to the inlet line (3) pump (27) and a Control element (28) is branched off. Installation according to claim 18, characterized in that from the supply line (15) into the Inlet line (3) opening line (45,26) with a pump in the direction of the inlet line (3) (27) and a control element (28) is branched off. Installation according to claim 18, characterized in that from the second heat exchanger (5) into the Recirculation line (7) leading line (29) with a Control element (50) is branched off. Installation according to claim 18, characterized in that from the container (6.6A) into the recirculation line (7) opening line (54) with the control element (55) is branched off. Installation according to claim 18, characterized in that from the supply line (15) into the Recirculation line (7) leading line (30,54) with the control element (55) is branched off.

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