CN103185414A - Method and device utilizing low-grade waste heat - Google Patents

Abstract

The invention provides a method for utilizing low-grade waste heat, which includes: introducing the flue gas discharged from the absorption direct-fired engine into a flue gas heat exchanger for sensible heat recovery; introducing the flue gas after sensible heat recovery into the flue gas condensing heat exchanger In the process, latent heat recovery is performed on the flue gas after recovery of sensible heat; the flue gas after recovery of latent heat is discharged, and the absorption direct combustion engine operates in the cooling season mode during the heating season, and the recovered sensible heat is replaced by the absorption direct combustion engine. The latent heat recovered from the hot water discharged from the circulating heating water outlet is replaced by the chilled water discharged from the circulating chilled water outlet of the absorption direct combustion engine. Low-grade waste heat utilization devices are also provided, including: absorption direct-fired engine; heating water input branch connected to the circulating heating water inlet, heating water output branch connected to the circulating heating water outlet; smoke from the absorption direct-fired machine A flue gas heat exchanger that recovers sensible heat from the flue gas discharged from the gas outlet; a flue gas condensing heat exchanger that recovers latent heat from the flue gas after recovering sensible heat. The invention can improve the heat utilization efficiency of the direct combustion engine.

Description

Method and device for utilizing low-grade waste heat

technical field

The invention relates to a method for utilizing low-grade waste heat and a device for utilizing low-grade waste heat.

Background technique

In the prior art, the waste heat recovery scheme of absorption direct-fired engine is mainly divided into two categories, one is to recover flue gas sensible heat by installing a flue gas heat exchanger on the flue of the direct-fired engine, and the other is to recover the sensible heat of the flue gas through the flue A condensing heat exchanger is installed to recover the sensible heat and part of the latent heat of the flue gas. The waste heat recovery of circulating cooling water is generally realized by electric drive heat pump.

Figure 1 is the process flow of the current conventional absorption direct combustion engine waste heat recovery. At present, the conventional absorption direct-fired engine system turns on the heating mode during the heating season, and its form is very similar to a gas-fired boiler. The gas 205 enters the absorption direct-fired engine 1 and directly transfers heat to the heating water direct-fired engine branch 210 , after the temperature rises, the output of the heating water main road 211 is formed. The process of improving the traditional process is usually to install a flue gas heat exchanger 202, separate the heating water flue gas heat exchange branch 209 from the heating water main road 208, enter the flue gas heat exchanger 202 for heat exchange, and directly return to the heating water main road 211 . Regulating valves 203 and 204 are respectively arranged on 209 and 210 to adjust the distribution of the flow of heating water trunk 208 in heating water flue gas heat exchange branch 209 and heating water direct combustion engine branch 210 . Due to the high temperature of the heating water main road 208 entering the system, only sensible heat can be replaced by the exhaust gas of the absorption direct combustion engine 206, and the waste heat recovery capacity is limited. If the temperature of the heating water trunk 208 is low, the requirements for the flue gas heat exchanger 202 are high, and it must be able to handle both sensible heat transfer and latent heat transfer, which is uneconomical.

There are two major technical defects in the existing technical solutions. One is that the waste heat recovery of the flue gas of the direct combustion engine has not been utilized in cascades. The physical properties of the flue gas are very different in the gaseous section and the condensation section. The smoke temperature is above 160°C, and the condensation temperature is around 80°C. If there is no distinction between two types of heat exchangers, the economy of the heat exchanger will become poor and the heat exchange area will be larger; the second is the direct combustion engine The heat of the flue gas does not match its rated thermal power. When using refrigeration to absorb waste heat, even if the latent heat of the flue gas is included, it can only meet about 25% of its rated power, and the rest of the cooling capacity is wasted because no corresponding waste heat source can be found .

Contents of the invention

In view of the problems existing in the related technologies, the object of the present invention is to provide a method for utilizing low-grade waste heat and a device for utilizing low-grade waste heat, so as to improve the heat utilization efficiency of the direct combustion engine system.

In order to achieve the above purpose, on the one hand, the present invention provides a method for utilizing low-grade waste heat, which includes: introducing the flue gas discharged from the absorption direct combustion engine into the flue gas heat exchanger and recovering the sensible heat of the flue gas therein ; Introduce the flue gas after recovering sensible heat into the flue gas condensing heat exchanger and perform latent heat recovery on the flue gas after recovering sensible heat; and discharge the flue gas after recovering latent heat, wherein, absorbing The direct-fired engine operates in the cooling season mode during the heating season, the recovered sensible heat is replaced by the hot water discharged from the circulating heating water outlet of the absorption direct-fired engine, and the recovered latent heat is replaced by the absorbed heat The chilled water discharged from the circulating chilled water outlet of the direct-fired engine.

Preferably, the method of the present invention also includes: introducing the chilled water discharged from the circulating chilled water outlet into the circulating cooling water heat exchanger to absorb the heat contained in the cooling water; After the chilled water is combined, it returns to the absorption direct combustion engine for heat release, and then the chilled water after heat release is discharged from the circulating chilled water outlet.

Preferably, the method of the present invention further includes: combining the chilled water discharged from the circulating chilled water outlet with the chilled water after absorbing latent heat; introducing the pooled chilled water into the circulating cooling water heat exchanger to absorb the heat contained in the cooling water ; and return the chilled water after absorbing the heat contained in the cooling water to the absorption direct-fired engine for heat release, and then discharge the chilled water after the heat release from the circulating chilled water outlet.

Preferably, the temperature of the flue gas discharged from the absorption direct-fired engine is above 160°C, and its condensation temperature is 80°C.

On the other hand, the present invention also provides a low-grade waste heat utilization device, which includes: an absorption direct combustion engine with a circulating heating water outlet, a circulating heating water inlet, a circulating chilled water inlet, a circulating chilled water outlet, and a flue gas outlet; and The heating water input branch connected to the circulating heating water inlet, the heating water output branch connected to the circulating heating water outlet; the flue gas heat exchanger for recovering sensible heat from the flue gas discharged from the flue gas outlet, which has the first and The second heat exchange channel, wherein the inlet of the first heat exchange channel communicates with the flue gas outlet, the inlet of the second heat exchange channel communicates with the heating water input branch, and the outlet of the second heat exchange channel communicates with the heating water output branch; The flue gas condensing heat exchanger for recovering latent heat from flue gas after recovering sensible heat has third and fourth heat exchange passages, wherein the inlet of the third heat exchange passage communicates with the outlet of the first heat exchange passage, and the second The inlets of the four heat exchange channels communicate with the circulating chilled water outlet, and the outlet of the fourth heat exchange channel communicates with the circulating chilled water inlet.

Preferably, the device of the present invention further includes: a circulating cooling water heat exchanger, which has fifth and sixth heat exchange channels, the inlet of the fifth heat exchange channel communicates with the outlet of circulating chilled water, and the outlet of the fifth heat exchange channel communicated with the circulating chilled water inlet; and a cooling water input branch communicated with the inlet of the sixth heat exchange channel, and a cooling water return branch communicated with the outlet of the sixth heat exchange channel.

Preferably, the device of the present invention further includes: a jumper, one end of which communicates with the outlet of the fourth heat exchange channel of the flue gas condensing heat exchanger, and the other end of which communicates with the inlet of the fifth heat exchange channel of the circulating cooling water heat exchanger communication; and a crossover valve connected to the crossover to control the flow of chilled water through the crossover.

Preferably, the heating water input branch is divided into a first branch pipeline and a second branch pipeline, wherein the first branch pipeline communicates with the circulating heating water inlet, and the second branch pipeline communicates with the second heat exchanger of the flue gas heat exchanger. The inlet of the hot aisle is connected.

Preferably, a flow regulating valve is respectively connected to the first branch pipeline and the second branch pipeline.

Preferably, at the outlet of the third heat exchange channel of the flue gas condensing heat exchanger, an exhaust pipe for exhausting the flue gas absorbed latent heat is connected.

The beneficial technical effects of the present invention are: for the flue gas discharged from the absorption direct combustion engine in the refrigeration mode, the flue gas heat exchanger is used to recover sensible heat, and the flue gas condensation heat exchanger is used to recover the flue gas after recovering sensible heat. The latent heat is recovered from the flue gas. This scheme of recovering the sensible heat and the latent heat of the flue gas separately by using the flue gas two-stage heat exchange method realizes the cascaded recovery of the low-grade waste heat of the absorption direct combustion engine. Further, because the heat exchanger used for exchanging heat with flue gas is divided into sensible heat and latent heat heat exchangers (ie, the flue gas heat exchanger and the flue gas condensing heat exchanger) not only The waste heat of the flue gas can be effectively used, and the requirements for the design, material and process control of the heat exchanger are correspondingly reduced, and the economy is better.

In addition, the present invention also introduces an auxiliary circulating cooling water heat exchanger to send the heat in the external circulating cooling water into the circulating chilled water of the absorption direct-fired engine as additional heat, which solves the problem in the prior art that the direct-fired engine flue gas The waste caused by the mismatch of heat and its rated thermal power is to solve the problem in the prior art that the waste heat of the flue gas is not enough to compensate the rated cooling power of the direct-fired engine.

Thus, when the absorption direct-fired engine operates in the cooling mode in the heating season, the present invention can recover all the heat taken away by the flue gas. Not only that, the waste heat brought by the above-mentioned external circulation cooling water can also be used by the present invention Nearly half of the heat is provided to upgrade it to heating heat that can be directly applied, and the thermal efficiency of the invention can be greatly improved. Therefore, the present invention obviously improves the waste heat utilization capacity and heat supply capacity of the direct combustion engine, and makes the control and adjustment of the device of the present invention more flexible.

Description of drawings

Fig. 1 is the process flow of conventional absorption direct combustion engine waste heat recovery in the prior art;

Fig. 2 is a schematic diagram of an embodiment of the low-grade waste heat utilization device of the present invention.

In Figure 2:

1 absorption direct combustion engine

2 Circulating cooling water heat exchanger

3 Flue gas condensing heat exchanger

4 flue gas heat exchanger

5 Inlet valve of chilled water branch circulating cooling water heat exchanger

6 Outlet valve of chilled water branch circulating cooling water heat exchanger

7 Cross-line valve

8 Inlet valve of chilled water branch condensing heat exchanger

9 Outlet valve of chilled water branch condensing heat exchanger

10 Heating water flue gas heat exchange branch regulating valve

11 Heating water direct combustion engine branch regulating valve

12 gas

13 Chilled water direct combustion engine outlet pipe

14 Chilled water condensing heat exchanger branch

15 Branch before the valve of chilled water circulation cooling water heat exchanger

16 across the line

17 Branch after the valve of chilled water circulation cooling water heat exchanger

18 Branch in front of the rear valve of the chilled water condensing heat exchanger

19 Branch after the valve after the chilled water condensing heat exchanger

20 Chilled water circulation cooling water heat exchanger rear branch

21 Chilled water direct-fired engine inlet pipe

22 Cooling water input branch

23 Cooling water output branch

24 Direct combustion engine flue gas outlet pipe

25 The flue gas of the direct-fired engine exits the pipeline after sensible heat exchange

26 flue gas exhaust pipe

27 Heating water input branch

28 The first branch pipeline

29 Heating water flue gas heat exchange branch

30 Heating water output branch

31 Heating water outlet.

Detailed ways

Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

Referring to Fig. 2, the method for utilizing low-grade waste heat of the present invention is described, which includes: introducing the flue gas discharged from the absorption direct combustion engine 1 into the flue gas heat exchanger 4 and recovering the sensible heat of the flue gas therein; The flue gas after the sensible heat is introduced into the flue gas condensing heat exchanger 3 and the latent heat recovery is performed on the flue gas after recovering the sensible heat; the flue gas after the latent heat is recovered is discharged, wherein the absorption direct combustion The machine 1 operates in the cooling season mode during the heating season, the recovered sensible heat is replaced by the hot water discharged from the circulating heating water outlet of the absorption direct combustion engine 1, and the recovered latent heat is replaced by the absorption direct combustion engine 1 Chilled water discharged from the circulating chilled water outlet of gas turbine 1.

Continue referring to Fig. 2, the method of the present invention also includes: the chilled water discharged from the circulating chilled water outlet 104 is introduced into the circulating cooling water heat exchanger 2 to absorb the heat contained in the cooling water; the chilled water after absorbing the cooling water heat, After merging with the chilled water that has absorbed latent heat, it returns to the absorption direct combustion engine 1 for heat release, and then the chilled water after heat release is discharged from the circulating chilled water outlet 104 . As an alternative, the method of the present invention also includes: merging the chilled water discharged from the circulating chilled water outlet with the chilled water after absorbing latent heat; introducing the pooled chilled water into the circulating cooling water heat exchanger 2 for absorption The heat contained in the cooling water; return the chilled water after absorbing the heat contained in the cooling water to the absorption direct combustion engine 1 for heat release, and then discharge the chilled water from the circulating chilled water outlet 104. Preferably, the temperature of the flue gas discharged from the absorption direct combustion engine 1 in the present invention is above 160°C, and its condensation temperature is 80°C.

On the other hand, the present invention also provides a low-grade waste heat utilization device, which includes: an absorption direct combustion engine 1 with a circulating heating water outlet 102, a circulating heating water inlet 101, a circulating chilled water inlet 105, and a circulating chilled water outlet 104 , the flue gas outlet 103; the heating water input branch 27 connected with the circulating heating water inlet 101, the heating water output branch 30 connected with the circulating heating water outlet 102; the sensible heat recovery of the flue gas discharged from the flue gas outlet The flue gas heat exchanger 4; the flue gas condensing heat exchanger 3 for recovering latent heat from the flue gas after sensible heat recovery. The flue gas heat exchanger 4 has first and second heat exchange passages, the entrance of the first heat exchange passage communicates with the flue gas outlet 103, the entrance of the second heat exchange passage communicates with the heating water input branch 27, and the second heat exchange passage communicates with the flue gas outlet 103. The outlet of the hot channel communicates with the heating water output branch 30 . The flue gas condensing heat exchanger 3 has a third and a fourth heat exchange channel, the inlet of the third heat exchange channel communicates with the outlet of the first heat exchange channel, the inlet of the fourth heat exchange channel communicates with the circulating chilled water outlet 104, The outlet of the fourth heat exchange channel communicates with the circulating chilled water inlet 105 . At the outlet of the third heat exchange channel of the flue gas condensing heat exchanger 3 , an exhaust pipe 26 for exhausting the flue gas absorbed latent heat is connected.

Shown in Fig. 2: the heating water input branch 27 is divided into the first branch pipeline 28, the second branch pipeline, wherein the first branch pipeline 28 communicates with the circulating heating water inlet 101, and the second branch pipeline communicates with the flue gas The inlet of the second heat exchange channel of the heat exchanger 4 is connected, and a flow regulating valve 11 and 10 are respectively connected to the first branch pipeline 28 and the second branch pipeline.

Further, as shown in FIG. 2 , the device of the present invention further includes: a circulating cooling water heat exchanger 2 , a cooling water input branch 22 , and a cooling water output branch 23 . The circulating cooling water heat exchanger 2 has fifth and sixth heat exchange channels, the inlet of the fifth heat exchange channel communicates with the circulating chilled water outlet 104, the outlet of the fifth heat exchange channel communicates with the circulating chilled water inlet 105, and the cooling water enters The branch 22 communicates with the inlet of the sixth heat exchange channel, and the cooling water output branch 23 communicates with the outlet of the sixth heat exchange channel.

Furthermore, FIG. 2 shows a jumper 16 and a jumper valve 7 connected to the jumper 16 , and the jumper valve 7 controls the flow of chilled water flowing through the jumper 16 . One end of the jumper 16 communicates with the outlet of the fourth heat exchange channel of the flue gas condensing heat exchanger 3 , and the other end of the jumper 16 communicates with the inlet of the fifth heat exchange channel of the circulating cooling water heat exchanger 2 .

Referring to Fig. 2, the workflow of an embodiment of the device of the present invention will be described.

The absorption direct-fired engine 1 operates in the cooling season mode during the heating season. The gas 12 enters the absorption direct-fired engine 1 and burns to produce chilled water. Branch 14, branch 15 in front of valve of chilled water circulation cooling water heat exchanger, chilled water enters flue gas condensing heat exchanger 3 through branch 14, wherein inlet valve 8 is installed on branch 14, chilled water passes through branch 15 Enter the circulating cooling water heat exchanger 2 through the inlet valve 5 and the branch 17. The chilled water from the branch 14 passes through the flue gas condensing heat exchanger 3 to heat up, passes through the branch 18 and the outlet valve 9, and then enters the branch 19 after the valve of the chilled water condensing heat exchanger; the chilled water from the branch 15 After the circulating cooling water heat exchanger 2 heats up, it enters the chilled water circulating cooling water heat exchanger through the outlet valve 6 and enters the rear branch 20. After the two converge, it enters the chilled water direct-fired engine inlet pipeline 21 and returns directly to the absorption direct-fired engine. 1. Constitute a closed loop of chilled water circulation.

Discharge flue gas from absorption direct combustion engine 1, enter flue gas heat exchanger 4 through direct combustion engine flue gas outlet pipeline 24, heating water branch 27 is used for inputting the heating water that comes out from the device of the present invention, heating water The branch 27 is divided into a first branch pipeline 28 and a second branch pipeline. The heating water enters the absorption direct combustion engine 1 through the first branch pipeline 28, and the heating water passes through the flue gas heat exchanger 4 to exchange heat with the flue gas. After exchanging heat with the device 4, it returns directly to the heating water output branch 30 through the heating water flue gas heat exchange branch 29, merges with the hot water from the branch 30, and then flows out from the heating water outlet 31 to supply clients and the like. After the flue gas discharged from the flue gas outlet pipeline 24 of the direct-fired engine enters the flue gas heat exchanger 4 for heat exchange, it passes through the flue gas sensible heat exchange of the direct-fired engine and then enters the flue gas condensing heat exchanger 3 through the outlet pipeline 25. The temperature of the flue gas from the pipeline 25 is relatively low, and the flue gas is condensed through the flue gas condensing heat exchanger 3 and then discharged from the flue gas exhaust pipe 26 . The cooling capacity of the absorption direct-fired engine 1 is strong, and the flue gas in the pipeline 24 cannot meet the remaining heat demand, so the cooling water is introduced into the branch 22, and the cooling water exchanges heat with the chilled water from the branch 15 and then cools through the The cooling water output branch 23 leaves the device of the invention. The jumper 16 in the system is for the adjustment of the jumper, so that the temperature distribution of the device of the present invention is reasonable when in use or switched under fault conditions.

For further understanding of the present invention, the related term that the present invention occurs is explained as follows:

Absorption direct-fired engine: Absorption direct-fired engine uses combustible gas to burn directly to provide refrigeration, heating and sanitary hot water. In refrigeration conditions, water is generally used as the refrigeration medium, and the refrigeration cycle is completed through low-temperature absorption and high-temperature desorption of lithium bromide solution. In the heating condition, it is similar to the waste heat boiler, and the heat of gas combustion is directly transferred to the heating water through the circulation of lithium bromide solution.

Flue gas: High-temperature gas products formed by the combustion of various combustible gases or fuel oil in the absorption direct-fired engine. The flue gas utilized by the direct-fired engine still contains a certain amount of sensible heat and a large amount of latent heat of condensation.

Circulating cooling water: Circulating water widely used in industry to cool down equipment. The cooling water cooled from the cooling water cooling tower is transported to the device to be cooled through the cooling water pipe network, and returned after heating up and then cooled down for reuse.

Flue gas heat exchanger: heat exchange equipment that uses water or other media to exchange heat with flue gas. It is generally a tube-and-tube or plate heat exchanger with a large body that mainly absorbs the sensible heat of flue gas.

Condensing heat exchanger: heat exchange equipment that uses water or other media to exchange heat with flue gas close to the dew point. It is generally a stainless steel plate heat exchanger with a relatively small body and mainly absorbs the latent heat of flue gas. It is equipped with a hydrophobic device to discharge the flue gas condensate.

Circulating cooling water heat exchanger: Heat exchange equipment in which both hot and cold media are water, most of which are plate heat exchangers, which are common heat exchangers with small volume and high efficiency, mostly made of stainless steel.

Referring to accompanying drawing 2, taking 220kw-230kw gas to generate heat energy 210kw (or cold energy 210kw) in absorption direct combustion engine 1 as an example, flue gas heat exchanger 4 absorbs sensible heat from flue gas 30kw, flue gas condensing heat exchanger 3 Absorb 35kw of latent heat from the flue gas, and absorb 160kw of cold energy from the circulating cooling water through the circulating cooling water heat exchanger 2. All the energy absorbed above is equivalent to about 150% of the heat of the gas entering the direct combustion engine 1 (this value is calculated according to the low calorific value of the gas). In comparison, under the same conditions, in the prior art shown in Fig. 1, the heating efficiency is 90%.

To sum up, the present invention uses a flue gas heat exchanger to recover sensible heat from the flue gas discharged from the absorption direct combustion engine in refrigeration mode, and uses a flue gas condensation heat exchanger to perform latent heat recovery on the flue gas after sensible heat recovery. Recovery, this scheme adopts flue gas two-stage heat exchange method to recover flue gas sensible heat and latent heat respectively, and realizes cascaded recovery of low-grade waste heat of absorption direct combustion engine. Further, because the heat exchanger used for exchanging heat with flue gas is divided into sensible heat and latent heat heat exchangers (ie, the flue gas heat exchanger and the flue gas condensing heat exchanger) not only The waste heat of the flue gas can be effectively used, and the requirements for the design, material and process control of the heat exchanger are correspondingly reduced, and the economy is better. In addition, the present invention also introduces an auxiliary circulating cooling water heat exchanger to send the heat in the external circulating cooling water into the circulating chilled water of the absorption direct-fired engine as additional heat, which solves the problem in the prior art that the direct-fired engine flue gas The waste caused by the mismatch of heat and its rated thermal power is to solve the problem in the prior art that the waste heat of the flue gas is not enough to compensate the rated cooling power of the direct-fired engine. Thus, when the absorption direct-fired engine operates in the cooling mode in the heating season, the present invention can recover all the heat taken away by the flue gas. Not only that, the waste heat brought by the above-mentioned external circulation cooling water can also be used by the present invention Nearly half of the heat is provided to upgrade it to heating heat that can be directly applied, and the thermal efficiency of the invention can be greatly improved. Therefore, the present invention obviously improves the waste heat utilization capacity and heat supply capacity of the direct combustion engine, and makes the control and adjustment of the device of the present invention more flexible.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. a method of utilizing low grade residual heat is characterized in that, comprising:

With the flue gas that absorption direct combustion machine (1) is discharged, introduce in the flue gas heat exchange device (4) and also therein described flue gas is carried out the sensible heat recovery;

With the flue gas behind the recovery sensible heat, introduce in the flue gas condensing formula heat exchanger (3) and also therein the flue gas behind the described recovery sensible heat is carried out the latent heat recovery; And

The fume emission that is recovered behind the latent heat is fallen,

Wherein, described absorption direct combustion machine (1) moves under refrigeration season pattern during season in heating, the sensible heat that reclaims is displaced to from the hot water that the circulation heating water out of described absorption direct combustion machine (1) is discharged, and the latent heat that reclaims is displaced to from the chilled water that the circulating frozen water out of described absorption direct combustion machine (1) is discharged.

2. method according to claim 1 is characterized in that, also comprises:

To absorb wherein cooling water institute heat content in the introducing recirculated cooling water heat exchanger (2) from the chilled water of described circulating frozen water out discharge;

With absorbing chilled water behind the cooling water heat, carrying out heat release with absorbing to return in the described absorption direct combustion machine (1) after chilled water behind the described latent heat converges, then the chilled water after the heat release is discharged from described circulating frozen water out.

3. method according to claim 1 is characterized in that, also comprises:

The chilled water that to discharge from described circulating frozen water out, converge with the chilled water that absorbs behind the described latent heat;

Chilled water after will converging is introduced in the recirculated cooling water heat exchanger (2) and is absorbed wherein cooling water institute heat content; And

Return in the described absorption direct combustion machine (1) and carry out heat release absorbing chilled water after the described cooling water institute heat content, then the chilled water after the heat release is discharged from described circulating frozen water out.

4. according to each described method among the claim 1-3, it is characterized in that the flue-gas temperature of discharging from described absorption direct combustion machine (1) is more than 160 ℃, its condensation temperature is 80 ℃.

5. low grade residual heat use device comprises:

Absorption direct combustion machine (1) has circulation heating water out (102), circulation heating water inlet (101), circulating frozen water inlet (105), circulating frozen water out (104), exhanst gas outlet (103);

The heating water input branch road (27) that is connected with described circulation heating water inlet (101), the heating water that is connected with described circulation heating water out (102) output branch road (30);

It is characterized in that, also comprise:

The flue gas of discharging from described exhanst gas outlet is carried out the flue gas heat exchange device (4) that sensible heat reclaims, it has first and second heat exchanger channels, wherein the entrance of first heat exchanger channels is communicated with described exhanst gas outlet (103), the entrance of second heat exchanger channels is communicated with described heating water input branch road (27), and the outlet of described second heat exchanger channels is communicated with described heating water output branch road (30);

Flue gas behind the recovery sensible heat is carried out the flue gas condensing formula heat exchanger (3) that latent heat reclaims, it has third and fourth heat exchanger channels, wherein the entrance of the 3rd heat exchanger channels is communicated with the outlet of described first heat exchanger channels, the entrance of the 4th heat exchanger channels is communicated with described circulating frozen water out (104), and the outlet of the 4th heat exchanger channels is communicated with described circulating frozen water inlet (105).

6. according to the device of claim 5, it is characterized in that, also comprise:

Recirculated cooling water heat exchanger (2), it has the 5th and the 6th heat exchanger channels, and the entrance of the 5th heat exchanger channels is communicated with described circulating frozen water out (104), and the outlet of the 5th heat exchanger channels is communicated with described circulating frozen water inlet (105); And

The cooling water input branch road (22) that is communicated with the entrance of described the 6th heat exchanger channels, the cooling water output branch road (23) that is communicated with described the 6th heat exchanger channels outlet.

7. according to the device of claim 6, it is characterized in that, also comprise:

Cross-line (16), the one end is communicated with the outlet of the 4th heat exchanger channels of described flue gas condensing formula heat exchanger (3), and its other end is communicated with the entrance of the 5th heat exchanger channels of described recirculated cooling water heat exchanger (2); And

Be connected the flow through cross-line valve (7) of chilled-water flow of described cross-line (16) of control on the described cross-line (16).

8. device according to claim 7, it is characterized in that, described heating water input branch road (27) is divided into first branch line (28), second branch line, wherein said first branch line (28) is communicated with described circulation heating water inlet (101), and described second branch line is communicated with the entrance of second heat exchanger channels of described flue gas heat exchange device (4).

9. device according to claim 8 is characterized in that,

On described first branch line (28), on described second branch line, be connected with a flow control valve (11,10) respectively.

10. device according to claim 5 is characterized in that,

In the exit of the 3rd heat exchanger channels of described flue gas condensing formula heat exchanger (3), be connected with the blast pipe (26) of discharging for the flue gas that is absorbed behind the latent heat.

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