Waste incineration power generation flue gas waste heat utilization system

Abstract

The invention provides a waste incineration power generation flue gas waste heat utilization system. The heat of flue gas is effectively utilized. The waste incineration power generation flue gas waste heat utilization system comprises a first heat exchanger and a front flue gas heat exchange part communicated with a tail flue, the front flue gas heat exchange part is provided with a sensible heat exchange medium outlet, and the first heat exchanger is provided with a sensible heat exchange medium inlet. A sensible heat exchange medium outlet of the front flue gas heat exchange part is communicated with a sensible heat exchange medium inlet of the first heat exchanger; a first refrigerant also circulates in the first heat exchanger; the sensible heat exchange medium can exchange heat with a first refrigerant in the first heat exchanger; or the waste incineration power generation flue gas waste heat utilization system further comprises a second heat exchanger provided with a sensible heat exchange medium inlet, and the sensible heat exchange medium outlet of the front flue gas heat exchange part communicates with the sensible heat exchange medium inlet of the second heat exchanger; a second refrigerant further circulates in the second heat exchanger, and the sensible heat exchange medium exchanges heat with the second refrigerant in the second heat exchanger.

Description

Technical Field

[0001] The present invention relates to the technical field of waste incineration power generation, and in particular to a waste incineration power generation flue gas waste heat utilization system. Background Art

[0002] With the acceleration of urbanization and the continuous increase in the amount of domestic waste, waste incineration power generation has been widely promoted and applied around the world as an efficient and energy-saving way of waste disposal. Waste incineration power generation technology can not only solve the problem of garbage accumulation to a certain extent, but also turn waste into treasure and create clean electricity resources by properly incinerating various types of garbage and converting the heat energy generated during the incineration process into electrical energy.

[0003] However, in the process of waste incineration power generation, the flue gas contains a large amount of heat. If this heat can be effectively utilized, it will be able to further improve the energy efficiency of waste incineration power generation. However, how to effectively utilize the heat in the flue gas has always been a key issue that needs to be solved in waste incineration power generation technology. Summary of the invention

[0004] The purpose of the present invention is to provide a waste incineration power generation flue gas waste heat utilization system, by improving the structure of the waste incineration power generation flue gas waste heat utilization system, so as to effectively utilize the heat of the flue gas.

[0005] To achieve the above-mentioned objectives, the present invention provides a waste incineration power generation flue gas waste heat utilization system, comprising a first heat exchanger and a front flue gas heat exchange part connected to the tail flue, the front flue gas heat exchange part having a sensible heat exchange medium outlet, the first heat exchanger having a sensible heat exchange medium inlet, the sensible heat exchange medium outlet of the front flue gas heat exchange part being connected to the sensible heat exchange medium inlet of the first heat exchanger; a first refrigerant also flows in the first heat exchanger; the sensible heat exchange medium can exchange heat with the first refrigerant in the first heat exchanger; or, the waste incineration power generation flue gas waste heat utilization system also includes a second heat exchanger provided with a sensible heat exchange medium inlet, the sensible heat exchange medium outlet of the front flue gas heat exchange part being connected to the sensible heat exchange medium inlet of the second heat exchanger; a second refrigerant also flows in the second heat exchanger, and the sensible heat exchange medium exchanges heat with the second refrigerant in the second heat exchanger.

[0006] In this way, the sensible heat of the flue gas can be used to heat the first refrigerant, or to heat the second refrigerant, thereby improving the utilization rate of the flue gas heat.

[0007] Optionally, the waste incineration power generation flue gas waste heat utilization system also includes a flue gas treatment system for recovering latent heat of flue gas. In the flow direction of the flue gas, the flue gas treatment system is connected to a downstream position of the front flue gas heat exchange part; a first refrigerant flows through the flue gas treatment system, and the first refrigerant exchanges heat in the flue gas treatment system to heat the first refrigerant at least once; in the flow direction of the first refrigerant, the flue gas treatment system is located upstream of the first heat exchanger.

[0008] By setting up a flue gas treatment system, the latent heat of the flue gas can be recovered, and the latent heat of the flue gas can be used to further heat the first refrigerant, thereby further improving the utilization rate of the flue gas heat.

[0009] Optionally, the flue gas treatment system includes a dehumidification tower for spraying a salt solution on the flue gas and a primary heat exchanger in liquid communication with the dehumidification tower, the first refrigerant also flows in the primary heat exchanger, and the first refrigerant performs heat exchange in the primary heat exchanger to perform a primary temperature increase. Thus, the flue gas treatment system can perform a primary temperature increase on the first refrigerant.

[0010] Optionally, the flue gas treatment system includes a cooling tower and a secondary heat exchanger in liquid communication with the cooling tower; in the flow direction of the flue gas, the cooling tower is located upstream of the moisture absorption tower; the first refrigerant also flows in the secondary heat exchanger, and in the flow direction of the first refrigerant, the secondary heat exchanger is located downstream of the primary heat exchanger; the first refrigerant after the first temperature increase is subjected to heat exchange in the secondary heat exchanger to be heated up a second time. Thus, the flue gas treatment system can perform a second temperature increase on the refrigerant after the first temperature increase.

[0011] Optionally, the flue gas treatment system further includes an evaporation component, which is used to evaporate and concentrate at least part of the discharge liquid of the moisture absorption tower to form steam; the evaporation component also includes a three-stage heat exchanger, which is used to circulate steam and the first refrigerant; in the circulation direction of the first refrigerant, the three-stage heat exchanger is located downstream of the two-stage heat exchanger; the first refrigerant exchanges heat with steam in the three-stage heat exchanger to perform three-stage heating. As a result, the flue gas treatment system can heat the refrigerant after the second heating three times.

[0012] Optionally, the evaporation component further includes an evaporation part, wherein the evaporation part contains the discharge liquid of the moisture absorption tower; the sensible heat exchange medium also flows in the evaporation part, and the sensible heat exchange medium exchanges heat with the discharge liquid in the evaporation part to evaporate the discharge liquid. In this way, the sensible heat exchange medium can be used as a heat source for the evaporation part, saving energy.

[0013] Optionally, a rear flue gas heat exchange unit is further included for heating the exhaust flue gas, wherein the flue gas inlet of the rear flue gas heat exchange unit is connected to the flue gas outlet of the flue gas heat exchange unit. The flue gas is heated to avoid damaging the chimney and flue.

[0014] Optionally, a post-smoke heat exchange unit for heating the exhaust smoke is further included, and the smoke inlet of the post-smoke heat exchange unit is connected to the smoke outlet of the smoke treatment system. The smoke is heated to avoid damaging the chimney and flue.

[0015] Optionally, after the sensible heat exchange medium exchanges heat with the exhaust liquid in the evaporation section, it is mixed with the sensible heat exchange medium in the flue gas heat exchange section to heat the flue gas.

[0016] Optionally, the first refrigerant is hot water network, and the second refrigerant is turbine condensate. In this way, the flue gas heat can be used to heat the hot water network in the heating season, and the flue gas heat can be used to heat the turbine condensate in the non-heating season.

[0017] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0019] Figure 1 This is a schematic diagram of a portion of the structure of a waste incineration power generation flue gas waste heat utilization system according to an embodiment of the present invention;

[0020] Figure 2 It is another structural schematic diagram of the flue gas waste heat utilization system for waste incineration power generation in an embodiment of the present invention.

[0021] Reference numerals:

[0022] 1-first refrigerant; 2-sensible heat exchange medium; 10-flue gas treatment system; 11-flue gas pretreatment subsystem; 111-pretreatment tower; 111a-primary spray device; 111b-pretreatment liquid collection chamber; 112-primary liquid supply assembly; 112a-circulating water tank; 112b-clarification tank; 112c-spray replenishment pump; 112d-alkali solution replenishment pump; 12-secondary convection heat exchange subsystem; 121-cooling tower; 121a-secondary spray device; 121b-secondary liquid collection chamber cavity; 122-recycling water pool; 123-secondary heat exchanger; 13-third-level salt solution moisture absorption system; 131-moisture absorption tower; 131a-third-level spray device; 131b-third-level liquid collecting cavity; 132-liquid storage tank; 133-first-level heat exchanger; 134-evaporation component; 134a-third-level heat exchanger; 134b-evaporation part; 14-front flue gas heat exchange part; 141-first heat exchanger; 142-second heat exchanger; 15-rear flue gas heat exchange part; 3-tail flue; 4-second refrigerant. DETAILED DESCRIPTION

[0023] The invention provides a waste incineration power generation flue gas waste heat utilization system, and improves the structure of the waste incineration power generation flue gas waste heat utilization system, thereby effectively utilizing the heat of the flue gas.

[0024] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0025] Relational terms such as “first” and “second” and the like are merely used to distinguish one component from another having the same name, but do not necessarily require or imply any such actual relationship or order between these components.

[0026] Please refer to Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of a portion of the structure of a waste incineration power generation flue gas waste heat utilization system according to an embodiment of the present invention; Figure 2 It is another structural schematic diagram of the flue gas waste heat utilization system for waste incineration power generation in an embodiment of the present invention.

[0027] The present invention provides a waste incineration power generation flue gas waste heat utilization system, comprising a flue gas treatment system 10 for recovering flue gas latent heat and a front flue gas heat exchange unit 14, wherein in the flow direction of the flue gas, the flue gas treatment system 10 is connected to the downstream position of the front flue gas heat exchange unit 14. In other words, the flue gas inlet of the front flue gas heat exchange unit 14 is connected to the tail flue 3, and the flue gas outlet is connected to the flue gas inlet of the flue gas treatment system 10, so that the flue gas of the tail flue 3 can enter the flue gas treatment system 10 through the front flue gas heat exchange unit 14.

[0028] The specific method of recovering the latent heat of flue gas by the flue gas treatment system 10 is described below.

[0029] In the present embodiment, the first refrigerant 1 flows in the flue gas treatment system 10 , and the first refrigerant 1 performs heat exchange at least once in the flue gas treatment system 10 , thereby increasing the temperature of the first refrigerant 1 .

[0030] Specifically, the flue gas treatment system 10 includes a flue gas pretreatment subsystem 11, a secondary convection heat exchange subsystem 12 and a tertiary salt solution moisture absorption system 13 which are sequentially arranged in the flue gas flow direction.

[0031] The flue gas pretreatment subsystem 11 comprises a pretreatment tower 111, a primary spray device 111a disposed in the pretreatment tower 111, a primary liquid supply assembly 112, etc. The primary liquid supply assembly 112 is used to provide primary spray liquid to the primary spray device 111a.

[0032] In a specific example, the primary spray liquid is an alkali solution with a set concentration. The primary liquid supply component 112 specifically includes a circulating water tank 112a, a clarification tank 112b, an alkali solution replenishment pump 112d and a spray liquid replenishment pump 112c.

[0033] The circulating water tank 112a is used to configure an alkali solution of a set concentration. Specifically, the pretreatment tower 111 is further provided with a pretreatment liquid collecting chamber 111b, which is connected to the circulating water tank 112a to discharge liquid into the circulating water tank 112a. At the same time, the alkali solution replenishing pump 112d is used to transport a high-concentration alkali solution into the circulating water tank 112a, and the high-concentration alkali solution is mixed with the mixed liquid from the pretreatment liquid collecting chamber 111b in the circulating water tank 112a to form an alkali solution of a set concentration.

[0034] Optionally, when the liquid level in the circulating water tank 112a is lower than the set liquid level, the spray replenishing pump 112c is turned on to replenish liquid into the circulating water tank 112a.

[0035] In this method, a clarification tank 112b can also be provided, and the pretreatment liquid collecting chamber 111b can discharge liquid into the circulating water tank 112a or into the clarification tank 112b, and the discharged liquid is precipitated in the clarification tank 112b and then transported from the clarification tank 112b to the circulating water tank 112a. The sludge formed by precipitation in the clarification tank 112b can be incinerated in a furnace or discharged, and the wastewater formed in the clarification tank 112b can also be discharged after wastewater treatment.

[0036] The secondary convection heat exchange subsystem 12 includes a cooling tower 121 connected to the flue gas outlet of the pretreatment tower 111. The cooling tower 121 is provided with a secondary spraying device 121a, which performs a spraying operation on the flue gas in the cooling tower 121. The cooling tower 121 is also provided with a secondary liquid collecting chamber 121b, which is used to collect liquid after the spraying operation.

[0037] In the cooling tower 121, the pretreated flue gas is mainly cooled, that is, the temperature of the spray liquid sprayed by the secondary spray device 121a is relatively low, so that convection heat exchange is performed on the pretreated flue gas, thereby utilizing the latent heat in the flue gas.

[0038] Specifically, the flue gas from the pretreatment tower 111 is saturated wet flue gas, which exchanges heat with the spray liquid in the cooling tower 121. At this time, the saturated wet flue gas will precipitate a large amount of condensed water. While precipitating the condensed water, the spray liquid will carry the latent heat in the flue gas and the condensed water generated by the flue gas and be collected in the secondary liquid collection chamber 121b. In this embodiment, in order to recycle the liquid in the secondary liquid collection chamber 121b, the spray liquid of the secondary spray device 121a is water. Since the purity of the water precipitated from the saturated wet flue gas is relatively high and the spray liquid is also water, the secondary liquid collection chamber 121b is connected to the reuse water pool 122 for subsequent recycling.

[0039] In this embodiment, in order to utilize the latent heat of this part of the flue gas, the secondary convection heat exchange subsystem 12 is further provided with a secondary heat exchanger 123 in liquid communication with the cooling tower 121, the secondary heat exchanger 123 is in communication with the secondary liquid collecting chamber 121b, the first refrigerant 1 is also circulated in the secondary heat exchanger 123, and the high-temperature water in the secondary liquid collecting chamber 121b can perform heat exchange with the first refrigerant 1 in the secondary heat exchanger 123 to heat the first refrigerant 1. At the same time, the temperature of the high-temperature water flowing through the secondary heat exchanger 123 drops, and the secondary heat exchanger 123 returns to the secondary spray device 121a to perform another spray cooling operation on the flue gas of the cooling tower 121.

[0040] At the same time, the secondary liquid collecting chamber 121b can also be connected to the aforementioned circulating water tank 112a through the aforementioned spraying liquid replenishing pump 112c to replenish water in the circulating water tank 112a, thereby reducing external water replenishment and saving energy.

[0041] A defogger is also provided in the cooling tower 121 . After the liquid water is removed from the flue gas by the defogger, the water vapor in the flue gas reaches a saturated state. At this time, the flue gas reaches the dew point temperature and is discharged into the tertiary salt solution moisture absorption system 13 .

[0042] The three-stage salt solution dehumidification system 13 includes a dehumidification tower 131 for spraying salt solution on the flue gas, and a three-stage spraying device 131a is arranged in the dehumidification tower 131 to spray the flue gas from the cooling tower 121. It also includes a three-stage liquid supply component to provide a salt solution with a set concentration to the three-stage spraying device 131a. The liquid formed after spraying is collected in the three-stage liquid collecting chamber 131b.

[0043] The saturated wet flue gas cooled by the cooling tower 121 enters the moisture absorption tower 131, that is, in the flow direction of the flue gas, the cooling tower 121 is located upstream of the moisture absorption tower 131; the flue gas outlet of the cooling tower 121 is connected to the flue gas inlet of the moisture absorption tower 131. When the salt solution with a set concentration is sprayed on the flue gas, it can absorb the water vapor in the flue gas and the latent heat of liquefaction of the water vapor, thereby recovering the latent heat of the saturated wet flue gas cooled by the cooling tower 121 for a second time, and the recovered heat is collected in the third-level liquid collection chamber 131b along with the liquid. The saturated flue gas cooled by the cooling tower 121 is further cooled and moisture-absorbed to form superheated flue gas. The superheated flue gas can be discharged directly from the chimney or discharged after heating the superheated flue gas. The discharge method of the superheated flue gas is further described in the later part of this application.

[0044] The three-stage liquid supply component includes a liquid storage tank 132 and a first-stage heat exchanger 133 liquid-connected to the desiccant tower 131. The liquid storage tank 132 is used to store the discharge liquid of the third-stage liquid collecting chamber 131b. The liquid inlet of the liquid storage tank 132 is connected to the third-stage liquid collecting chamber 131b, and the liquid outlet of the liquid storage tank 132 is connected to the liquid inlet of the first-stage heat exchanger 133.

[0045] Specifically, the liquid storage tank 132 contains the high-temperature salt solution from the tertiary liquid collecting chamber 131b, and the high-temperature salt solution exchanges heat with the first refrigerant 1 in the primary heat exchanger 133 to increase the temperature of the first refrigerant. The cooled salt solution is then returned to the tertiary spray device 131a through the primary heat exchanger 133 to be circulated by the tertiary spray device 131a.

[0046] As an optional example, in the flow direction of the first refrigerant 1, the secondary heat exchanger 123 is located downstream of the primary heat exchanger 133; the first refrigerant 1 after the first heating is subjected to heat exchange in the secondary heat exchanger 123 for secondary heating.

[0047] Specifically, the first refrigerant 1 outlet of the primary heat exchanger 133 is connected to the first refrigerant 1 inlet of the aforementioned secondary heat exchanger 123. After the first refrigerant 1 is heated once in the primary heat exchanger 133, it enters the secondary heat exchanger 123 for secondary heating. In this way, the temperature of the flue gas can be utilized in a step-by-step manner, and the utilization rate of the flue gas heat by the first refrigerant 1 is also increased. Of course, the heat exchange mediums of the primary heat exchanger 133 and the secondary heat exchanger 123 can also be different, so as to heat and heat different heat exchange media.

[0048] In the above-mentioned embodiment, the concentration of the salt solution collected in the tertiary liquid collecting chamber 131b decreases. In order to provide the tertiary spraying device 131a with a salt solution meeting the required concentration, the tertiary salt solution desiccant system 13 is further provided with an evaporation component 134, which is used to evaporate and concentrate at least part of the discharge liquid of the desiccant tower 131 to form steam.

[0049] Specifically, the evaporation component 134 is connected to the liquid storage tank 132. The salt solution in the liquid storage tank 132 is the dilute salt solution from the third liquid collecting chamber. A part of the dilute salt solution enters the secondary heat exchanger 123 to exchange heat with the first refrigerant 1, and the other part of the dilute salt solution enters the evaporation component 134 to evaporate and concentrate to form a concentrated salt solution. At the same time, the distilled water formed after evaporation is supplemented to the reuse water pool 122 to be reused within the factory.

[0050] The evaporated concentrated salt solution enters the primary heat exchanger 133 and mixes with the dilute salt solution in the primary heat exchanger 133 until the set concentration is reached. After heat exchange and cooling by the first refrigerant 1, the concentrated salt solution is output to the tertiary spray device 131a to circulate and spray the flue gas.

[0051] In order to further utilize the heat of the evaporation component 134, a three-stage heat exchanger 134a is also provided in the evaporation component 134. The three-stage heat exchanger 134a is used for the circulation of steam and the circulation of the first refrigerant 1. In the circulation direction of the first refrigerant 1, the three-stage heat exchanger 134a is located downstream of the two-stage heat exchanger 123, that is, the outlet of the first refrigerant 1 of the two-stage heat exchanger 123 is connected to the inlet of the first refrigerant 1 of the three-stage heat exchanger 134a.

[0052] The three-stage heat exchanger 134a is used to circulate the steam formed in the evaporation component 134. The steam forms condensed water after heat exchange with the first refrigerant 1 in the three-stage heat exchanger 134a. The condensed water can also flow back to the recycling water pool 122 for reuse in the whole plant. In this embodiment, the three-stage heat exchanger 134a heats up the first refrigerant 1 three times. In this way, the heat can be further utilized in a gradient manner.

[0053] The heat source for evaporating the dilute salt solution in the evaporation component 134 may be steam or the heat of flue gas.

[0054] In order to achieve efficient use of energy, the waste incineration power generation flue gas waste heat utilization system in the present application also includes a front flue gas heat exchange unit 14, which can allow the flue gas of the tail flue 3 to circulate while exchanging heat with the second heat exchange medium flowing therein. Definition: A sensible heat exchange medium 2 circulates in the front flue gas heat exchange unit 14.

[0055] Specifically, the front flue gas heat exchange unit 14 has a flue gas inlet and a flue gas outlet, the flue gas inlet is connected to the tail flue 3, and the flue gas outlet is connected to the flue gas treatment system 10, specifically, the flue gas inlet of the aforementioned pretreatment tower 111. That is to say, in the flow direction of the flue gas, the front flue gas heat exchange unit 14 is located between the flue gas outlet of the tail flue 3 and the flue gas inlet of the pretreatment tower 111.

[0056] Thus, the heat of the flue gas before entering the flue gas treatment system 10 can be utilized to heat the sensible heat exchange medium 2 .

[0057] In order to effectively utilize the heat of this part of the flue gas, this part of the heat is used as a heat source for the aforementioned evaporation component 134 to heat and concentrate the dilute salt solution. Specifically, the evaporation component 134 also includes an evaporation portion 134b, and the evaporation portion 134b contains the dilute salt solution (the discharge liquid of the moisture absorption tower 131), and the sensible heat exchange medium 2 also flows in the evaporation portion 134b, and the sensible heat exchange medium 2 performs heat exchange with the discharge liquid in the evaporation portion 134b to evaporate the discharge liquid.

[0058] That is, the sensible heat exchange medium 2 inlet of the evaporation section 134b is also connected to the second medium outlet of the front flue gas heat exchange section 14, and the second medium inlet of the front flue gas heat exchange section 14 is connected to the sensible heat exchange medium 2 outlet of the evaporation section 134b, so that the sensible heat exchange medium 2 can form a circulation between the front flue gas heat exchange section 14 and the evaporation section 134b.

[0059] The sensible heat exchange medium 2 in the front flue gas heat exchange section 14 can flow through the evaporation section 134b and exchange heat with the dilute salt solution in the evaporation section 134b to heat and concentrate the dilute salt solution. In this way, the heat of the flue gas in front of the flue gas treatment system 10 can be effectively used to provide heat energy for the evaporation component 134, thereby improving the thermal energy utilization efficiency of the flue gas itself, avoiding the use of an external heat source to heat the evaporation component 134, and effectively saving energy.

[0060] In order to further utilize this part of heat energy, the waste incineration power generation flue gas waste heat utilization system also includes a first heat exchanger 141, and the sensible heat exchange medium 2 is circulated and connected between the first heat exchanger 141 and the front flue gas heat exchange part 14. Specifically, the sensible heat exchange medium 2 inlet of the first heat exchanger 141 is connected to the sensible heat exchange medium 2 outlet of the front flue gas heat exchange part 14, and the sensible heat exchange medium 2 outlet of the first heat exchanger 141 is connected to the sensible heat exchange medium 2 inlet of the front flue gas heat exchange part 14. Another heat exchange medium is also connected in the first heat exchanger 141. In one example, the other heat exchange medium in the first heat exchanger 141 is the first refrigerant 1.

[0061] In one embodiment, the flue gas from the tail flue 3 exchanges heat with the sensible heat exchange medium 2 flowing therethrough in the front flue gas heat exchange section 14 to heat the sensible heat exchange medium 2. The heated sensible heat exchange medium 2 exchanges heat with the first refrigerant 1 in the first heat exchanger 141 to heat the first refrigerant 1.

[0062] Alternatively, the first refrigerant 1 inlet of the first heat exchanger 141 is also connected to the first refrigerant 1 outlet of the aforementioned primary heat exchanger 133, that is, in the flow direction of the first refrigerant 1, the flue gas treatment system 10 is located upstream of the first heat exchanger 141. The first refrigerant 1, which has been heated three times, exchanges heat with the sensible heat exchange medium 2 in the first heat exchanger 141, thereby heating up for the fourth time. In these four heating times, the heat of the flue gas can be utilized step by step through the first refrigerant 1, which significantly improves the utilization efficiency of the flue gas.

[0063] In the above manner, the first refrigerant 1 can be water in the heating network. When the heating network needs to work, the waste incineration power generation flue gas waste heat utilization system of the present application utilizes the temperature of the flue gas step by step, thereby achieving heating of the water in the heating network.

[0064] In another optional example, the waste incineration power generation flue gas waste heat utilization system further includes a second heat exchanger 142, a sensible heat exchange medium 2 circulates in the front flue gas heat exchange unit 14 and the second heat exchanger 142, the sensible heat exchange medium 2 inlet of the second heat exchanger 142 is connected to the sensible heat exchange medium 2 outlet of the front flue gas heat exchange unit 14, and the sensible heat exchange medium 2 outlet of the second heat exchanger 142 is connected to the sensible heat exchange medium 2 inlet of the front flue gas heat exchange unit 14. A second refrigerant 4 also circulates in the second heat exchanger 142, and the heated sensible heat exchange medium 2 performs heat exchange with the second refrigerant 4 in the second heat exchanger 142 to increase the temperature.

[0065] Specifically, the sensible heat exchange medium 2 exchanges heat with the second refrigerant 4 in the second heat exchanger 142 in the second heat exchanger 142. For example, the heat exchange medium in the second heat exchanger 142 is turbine condensate, so that the heat of the flue gas can be used to heat the turbine condensate. In this embodiment, the heat of the flue gas can be used to heat the turbine condensate when the heating network does not need to work.

[0066] Of course, when the heating network does not need to work, the turbine condensate can be used as the first refrigerant 1, so that the flue gas treatment system 10 can also heat the turbine condensate multiple times, thereby realizing the utilization of flue gas waste heat. The type of the first refrigerant 1 can be selected by those skilled in the art according to their needs.

[0067] In the above scheme, the front flue gas heat exchange unit 14 can exchange heat with the flue gas before the flue gas enters the flue gas treatment system 10, thereby effectively utilizing the sensible heat of the flue gas. The flue gas after the sensible heat is recovered enters the flue gas treatment system 10, and the flue gas treatment system 10 utilizes the latent heat in the flue gas by treating the flue gas. Both the sensible heat and the latent heat of the flue gas can be used to heat the first refrigerant 1 in multiple stages through the corresponding heat exchangers, thereby realizing the step-by-step utilization of the heat of the flue gas by using the first refrigerant 1.

[0068] In other embodiments of the present application, the method of discharging the superheated flue gas discharged from the moisture absorption tower 131 is described.

[0069] The flue gas discharged from the moisture absorption tower 131 is in a superheated state. If the superheat of the flue gas is small, there is still a risk of corrosion to the flue and the chimney. In order to increase the superheat of the flue gas, the waste incineration power generation flue gas waste heat utilization system is also provided with a rear flue gas heat exchange part 15. The difference between the rear flue gas heat exchange part 15 and the front flue gas heat exchange part 14 is that the front flue gas heat exchange part 14 is used to cool the flue gas and utilize the sensible heat of the flue gas, while the rear flue gas heat exchange part 15 is used to heat the flue gas, thereby increasing the superheat of the discharged flue gas.

[0070] The rear flue gas heat exchange section 15 is connected between the chimney and the flue gas outlet of the moisture absorption tower 131. The superheated flue gas exchanges heat with the heat exchange medium flowing through the rear flue gas heat exchange section 15 in the rear flue gas heat exchange section 15, thereby increasing the temperature of the flue gas discharged to the outside. The heat exchange medium in the rear flue gas heat exchange section 15 is a sensible heat exchange medium 2, so that the sensible heat of the flue gas recovered by the front flue gas heat exchange section 14 can be used to heat the flue gas discharged to the outside, and the sensible heat exchange medium 2 after cooling flows back to the inlet of the front flue gas heat exchange section 14 to perform a new round of heat exchange with the flue gas in the tail flue 3. In this way, the waste heat of the flue gas can be recycled and the heat balance of the internal system can be achieved.

[0071] Of course, the flue gas inlet of the rear flue gas heat exchange part 15 may be directly connected to the flue gas outlet of the front flue gas heat exchange part 14 to heat up the flue gas at the outlet of the flue gas treatment system 10 .

[0072] In another embodiment, in order to maximize the utilization of the heat of the sensible heat exchange medium 2, the outlet of the sensible heat exchange medium 2 of the evaporator 134b is connected to the inlet of the sensible heat exchange medium 2 of the post-flue gas heat exchange section 15, thereby further cooling the sensible heat exchange medium 2 and maximizing the utilization of its heat.

[0073] In each of the above implementations, the number of garbage incinerators can be one or more. In the case of multiple garbage incinerators, the tail flue 3 corresponds to the garbage incinerators one by one. In this case, there are multiple front flue gas heat exchange parts 14, and the multiple front flue gas heat exchange parts 14 are connected to the tail flue 3 one by one. Those skilled in the art can choose to open at least one front flue gas heat exchange part 14 according to the demand for flue gas heat.

[0074] By adopting the technical solution of the present application, the sensible heat and latent heat of the flue gas can be recovered, and the flue gas can be processed and purified at the same time. The cooling tower 121 can ensure that the temperature of the flue gas is reduced to a lower level, so that the moisture absorption tower 131 only needs to reduce the moisture content of the low-temperature flue gas. By utilizing the sensible heat of the flue gas to provide a heat source for the evaporation system, the energy utilization efficiency is improved. In addition, by heating the exhaust flue gas, the superheat of the exhaust flue gas is increased to prevent corrosion of the flue and chimney. The heating and supplementary heat requirements of the first refrigerant 1 (hot network water) are also realized through several heat exchangers, thereby further improving the utilization efficiency of heat and saving operating costs.

[0075] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A waste incineration power generation flue gas waste heat utilization system, characterized in that: It comprises a first heat exchanger (141) and a front flue gas heat exchange section (14) connected to a tail flue (3), the front flue gas heat exchange section (14) having a sensible heat exchange medium (2) outlet, the first heat exchanger having a sensible heat exchange medium (2) inlet, the sensible heat exchange medium (2) outlet of the front flue gas heat exchange section (14) being connected to the sensible heat exchange medium (2) inlet of the first heat exchanger; A first refrigerant (1) also flows in the first heat exchanger (141); the sensible heat exchange medium (2) can exchange heat with the first refrigerant (1) in the first heat exchanger (141); or, The waste incineration power generation flue gas waste heat utilization system also includes a second heat exchanger (142) provided with an inlet for a sensible heat exchange medium (2); the sensible heat exchange medium (2) outlet of the front flue gas heat exchange unit (14) is connected to the sensible heat exchange medium (2) inlet of the second heat exchanger (142); a second refrigerant (4) also flows in the second heat exchanger (142); the second refrigerant (4) performs heat exchange with the sensible heat exchange medium (2) in the second heat exchanger (142).

2. The waste incineration power generation flue gas waste heat utilization system according to claim 1 is characterized in that: It also includes a flue gas treatment system (10) for recovering latent heat of flue gas, wherein the flue gas treatment system (10) is connected to the tail flue (3) and is located downstream of the front flue gas heat exchange section (14) in the flow direction of the flue gas; A first refrigerant (1) flows in the flue gas treatment system (10), and the first refrigerant (1) performs heat exchange at least once in the flue gas treatment system (10); In the flow direction of the first refrigerant (1), the flue gas treatment system (10) is located upstream of the first heat exchanger (141).

3. The waste incineration power generation flue gas waste heat utilization system according to claim 2 is characterized in that: The flue gas treatment system (10) comprises a dehumidification tower (131) for spraying a salt solution on the flue gas, and a primary heat exchanger (133) in liquid communication with the dehumidification tower (131). A first refrigerant (1) also flows in the primary heat exchanger (133). The first refrigerant (1) performs heat exchange in the primary heat exchanger (133) to perform a primary temperature increase.

4. The waste incineration power generation flue gas waste heat utilization system according to claim 3 is characterized in that: The flue gas treatment system (10) comprises a cooling tower (121) and a secondary heat exchanger (123) in liquid communication with the cooling tower (121); In the flow direction of the flue gas, the cooling tower (121) is located upstream of the moisture absorption tower (131); the first refrigerant (1) also flows in the secondary heat exchanger (123), and in the flow direction of the first refrigerant (1), the secondary heat exchanger (123) is located downstream of the primary heat exchanger (133); the first refrigerant (1) after the first heating is subjected to heat exchange in the secondary heat exchanger (123) for secondary heating.

5. The waste incineration power generation flue gas waste heat utilization system according to claim 4 is characterized in that: The flue gas treatment system (10) further comprises an evaporation component (134), wherein the evaporation component (134) is used to evaporate and concentrate at least part of the exhaust liquid of the moisture absorption tower (131) to form steam; The evaporation component (134) further comprises a three-stage heat exchanger (134a), wherein the three-stage heat exchanger (134a) is used for the circulation of the steam and the circulation of the first refrigerant (1); in the circulation direction of the first refrigerant (1), the three-stage heat exchanger (134a) is located downstream of the two-stage heat exchanger (123); The first refrigerant (1) after the second heating is subjected to heat exchange with the steam in the third-stage heat exchanger (134a) to be heated for the third time.

6. The waste incineration power generation flue gas waste heat utilization system according to claim 5 is characterized in that: The evaporation component (134) further comprises an evaporation portion (134b), wherein the evaporation portion (134b) contains the discharge liquid of the moisture absorption tower (131); A sensible heat exchange medium (2) also flows in the evaporation section (134b), and the sensible heat exchange medium (2) performs heat exchange with the exhaust liquid in the evaporation section (134b) to evaporate the exhaust liquid.

7. The waste incineration power generation flue gas waste heat utilization system according to any one of claims 1 to 6, characterized in that: It also comprises a rear smoke heat exchange portion (15) for heating smoke exhausted to the outside, wherein a smoke inlet of the rear smoke heat exchange portion (15) is connected to a smoke outlet of the front smoke heat exchange portion (14).

8. The waste incineration power generation flue gas waste heat utilization system according to any one of claims 2 to 6, characterized in that: The system further comprises a rear flue gas heat exchange section (15) for heating the flue gas discharged to the outside, wherein the flue gas inlet of the rear flue gas heat exchange section (15) is connected to the flue gas outlet of the flue gas treatment system (10). A sensible heat exchange medium (2) also flows in the flue gas heat exchange section (15), and the sensible heat exchange medium (2) heats the flue gas mixed with the front flue gas heat exchange section (14) and the flue gas treatment system (10). Optionally, after the sensible heat exchange medium (2) exchanges heat with the exhaust liquid in the evaporation section (134b), it is mixed with the sensible heat exchange medium (2) in the flue gas heat exchange section (15) to heat the flue gas.

9. The waste incineration power generation flue gas waste heat utilization system according to any one of claims 1 to 6, characterized in that: The first refrigerant (1) is hot water from a heating network, and the second refrigerant (4) is condensate from a steam turbine.

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