CN220583168U - Cascade utilization system for waste heat of continuous drainage of boiler of power plant - Google Patents

Abstract

The utility model belongs to the technical field of waste heat recovery, and particularly relates to a cascade utilization system of waste heat of continuous drainage of a boiler of a power plant. The utility model provides a power plant boiler even drains waste heat cascade utilization system includes: a drain main pipe is connected; the drainage branch pipe is connected with the drainage main pipe and is connected with a first-stage heat exchange device, a second-stage heat exchange device and a third-stage heat exchange device; the first-stage heat exchange device, the second-stage heat exchange device and the third-stage heat exchange device are connected in series into the continuous drainage branch pipe, so that the temperature of continuous drainage is reduced to the lowest extent through cascade utilization, and the waste heat of continuous drainage can be fully recovered.

Description

Cascade utilization system for waste heat of continuous drainage of boiler of power plant

Technical Field

The utility model belongs to the technical field of waste heat recovery, and particularly relates to a cascade utilization system of waste heat of continuous drainage of a boiler of a power plant.

Background

The boiler pollution discharge is one of losses in boiler operation, and in order to control the quality of boiler water and steam, the boiler must continuously discharge the boiler water from the position with highest saline-alkali concentration of the boiler water, so as to reduce the salt content, alkali content, silicic acid content and slag content in suspended state in the boiler water. The heat loss is also one of the important factors affecting the boiler benefit, and because the part of continuous drainage belongs to sewage drainage, a small amount of the sewage is generally recovered by simple flash evaporation of the continuous drainage expansion vessel, and the rest part of the sewage is directly discharged into a sewage drainage cooling pond, so that huge energy waste and environmental pollution are caused.

In recent years, in order to reduce consumption of power consumption in a plant, power generation efficiency is improved, and particularly, waste heat utilization of the power plant is important. At present, most of power plants recover waste heat of continuous drainage water of a boiler for heating dormitory buildings of the power plants, and the scheme is shown in fig. 1: the 130 ℃ continuous drainage plate-feeding heat exchanger exchanges heat with 40 ℃ heating backwater, the continuous drainage temperature is reduced to 70 ℃ and is discharged to a pollution discharge cooling pool, and the 40 ℃ heating backwater is pressurized by a heating circulating pump, fed into the plate-feeding heat exchanger, heated to 50 ℃ by continuous drainage and then sent to the heating tail end.

However, in the above system, because the temperature of the heating backwater is higher, and the plate heat exchanger has temperature difference loss during heat exchange, the drainage temperature of the boiler drainage water cannot be lower than the temperature of the heating backwater, the drainage temperature is still very high, the heat cannot be fully utilized, and the drainage water temperature of 70 ℃ is continuous, so that heat pollution exists to the surrounding environment.

Disclosure of Invention

The utility model aims to provide a cascade utilization system for waste heat of continuous drainage of a boiler of a power plant, which aims to solve the technical problem of insufficient utilization of waste heat of continuous drainage of the boiler in the prior art.

The application provides a power plant boiler even discharges waste heat cascade utilization system. This power plant boiler even discharges waste heat cascade utilization system includes: a drain main pipe is connected; the drainage branch pipe is connected with the drainage main pipe and is connected with a first-stage heat exchange device, a second-stage heat exchange device and a third-stage heat exchange device; the first-stage heat exchange device, the second-stage heat exchange device and the third-stage heat exchange device are connected in series and connected with a drainage branch pipe.

In an embodiment of the present application, the first stage heat exchange device and the third stage heat exchange device exchange heat with a heating water pipe system.

In an embodiment of the present application, the first stage heat exchange device and the second stage heat exchange device are plate heat exchangers.

In an embodiment of the present application, the water inlet side of the second stage heat exchange device is connected with a demineralized water supply pipe, and the water outlet side is connected with a deaerator water supplementing pipe.

In an embodiment of the present application, the third stage heat exchange device is a water source heat pump unit.

Correspondingly, the application provides a cascade utilization system for waste heat of continuous drainage of a boiler of a power plant. This power plant boiler even discharges waste heat cascade utilization system includes: a drain main pipe is connected; the drainage branch pipe is connected with the drainage main pipe and is connected with a first-stage heat exchange device, a second-stage heat exchange device and a third-stage heat exchange device; and the control valve group is used for connecting a single device in the first-stage heat exchange device, the second-stage heat exchange device and the third-stage heat exchange device or connecting more than two devices in series into the drainage branch pipe.

In an embodiment of the present application, the control valve group includes a stop valve M1, a stop valve M2, a stop valve M3, a stop valve M4, a stop valve M5, a stop valve M6, a stop valve M7, a stop valve M8, and a stop valve M9; the stop valves M1, M3 and M5 are used for controlling the on-off of a water inlet pipe and a continuous drainage branch pipe at the high temperature side of the first-stage heat exchange device, the second-stage heat exchange device and the third-stage heat exchange device respectively; the stop valve M2, the stop valve M4 and the stop valve M6 are respectively used for controlling the on-off of a water outlet pipe at the high temperature side of the first-stage heat exchange device, the second-stage heat exchange device and the third-stage heat exchange device and the continuous drainage branch pipe; the stop valve M7, the stop valve M8 and the stop valve M9 are arranged on the continuous drainage branch pipe and are respectively used for controlling the on-off of a pipe section positioned between water inlet and outlet pipes of the first-stage heat exchange device, a pipe section positioned between water inlet and outlet pipes of the second-stage heat exchange device and a pipe section positioned between water inlet and outlet pipes of the third-stage heat exchange device on the continuous drainage branch pipe.

In an embodiment of the present application, the first stage heat exchange device and the third stage heat exchange device exchange heat with a heating water pipe system.

In an embodiment of the present application, the first stage heat exchange device and the second stage heat exchange device are plate heat exchangers; the third-stage heat exchange device is a water source heat pump unit.

In an embodiment of the present application, the water inlet side of the second stage heat exchange device is connected with a demineralized water supply pipe, and the water outlet side is connected with a deaerator water supplementing pipe.

The beneficial effects of the utility model are as follows:

unlike the prior art, the application provides a power plant boiler even discharges waste heat cascade utilization system. This power plant boiler even discharges waste heat cascade utilization system includes: a drain main pipe is connected; the drainage branch pipe is connected with the drainage main pipe and is connected with a first-stage heat exchange device, a second-stage heat exchange device and a third-stage heat exchange device; the first-stage heat exchange device, the second-stage heat exchange device and the third-stage heat exchange device are connected in series into the continuous drainage branch pipe, so that the temperature of continuous drainage is reduced to the lowest extent through cascade utilization, and the waste heat of continuous drainage can be fully recovered.

Additional features and advantages of the utility model will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model. The objectives and other advantages of the utility model will be realized and attained by the structure particularly pointed out in the written description and drawings.

In order to make the above objects, features and advantages of the present utility model more comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present utility model, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a prior art continuous drain waste heat recovery system;

FIG. 2 is a schematic diagram of a power plant boiler tie-down waste heat cascade utilization system in accordance with a preferred embodiment of the present utility model;

FIG. 3 is a schematic diagram of a power plant boiler continuous drain waste heat cascade utilization system in a heating season according to a preferred embodiment of the present utility model;

fig. 4 is a schematic diagram of a power plant boiler continuous drain waste heat cascade utilization system in non-heating season according to a preferred embodiment of the present utility model.

In the figure:

a main drainage pipe 100, a branch drainage pipe 200, a heating water pipe system 300, a first-stage heat exchange device 1, a second-stage heat exchange device 2 and a third-stage heat exchange device 3.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

The application provides a power plant boiler even discharges waste heat cascade utilization system, and the following is respectively explained in detail. It should be noted that the following description order of the embodiments is not intended to limit the preferred order of the embodiments of the present application. In the following embodiments, the descriptions of the embodiments are focused on, and for the part that is not described in detail in a certain embodiment, reference may be made to the related descriptions of other embodiments.

In order to solve the technical problem of the waste heat recovery and supplement of continuous drainage in the prior art, the utility model relates to a cascade utilization system of waste heat of continuous drainage of a power plant boiler. This power plant boiler even discharges waste heat cascade utilization system includes: a drain main pipe is connected; the drainage branch pipe is connected with the drainage main pipe and is connected with a first-stage heat exchange device, a second-stage heat exchange device and a third-stage heat exchange device; the first-stage heat exchange device, the second-stage heat exchange device and the third-stage heat exchange device are connected in series into the continuous drainage branch pipe, so that the temperature of continuous drainage is reduced to the lowest extent through cascade utilization, and the waste heat of continuous drainage can be fully recovered. As will be described in detail below.

Referring to fig. 2, in one embodiment, a power plant boiler continuous drain waste heat cascade utilization system may include: a drainage master pipe 100, a drainage branch pipe 200, a first-stage heat exchange device 1, a second-stage heat exchange device 2 and a third-stage heat exchange device 3.

Specifically, one end of the drainage mother pipe 100 may be connected to a sewage source of a boiler, and the other end is a drainage end.

The water inlet and outlet ends of the drainage branch pipe 200 can be connected with the drainage main pipe 100, and the drainage in the drainage main pipe 100 can flow through the drainage branch pipe 200 by arranging a plurality of valves; the arrangement of the drainage branch pipe 200 facilitates the arrangement of the equipment and devices such as the first-stage heat exchange device 1, the second-stage heat exchange device 2, the third-stage heat exchange device 3 and the like.

The first-stage heat exchange device 1, the second-stage heat exchange device 2 and the third-stage heat exchange device 3 are connected in series to the drainage branch pipe 200, and can be connected in series to the drainage branch pipe 200, so that the temperature of drainage is reduced to the lowest degree through cascade utilization, and waste heat of drainage can be fully recovered.

In one embodiment, the first stage heat exchange device 1 and the third stage heat exchange device 3 may exchange heat with the heating water pipe system 300; in other words, the first-stage heat exchange device 1 and the third-stage heat exchange device 3 can use the waste heat of the drainage water in the drainage master 100 for heating.

In an embodiment, the first stage heat exchange device 1 and the second stage heat exchange device 2 may be plate heat exchangers; the demineralized water feed pipe is connected to the water inlet side of second level heat transfer device 2, and the deaerator moisturizing pipe is connected to the water outlet side, of course, in other embodiments of this application, in the object of second level heat transfer device 2 heating, not only heating demineralized water, but also other water sources that need heating and be close to ambient temperature, such as running water moisturizing of living hot water tank, etc. can be selected to heat.

Considering that the temperature of the continuous drainage water can reach 20 ℃ in some application scenarios after two-stage waste heat recovery through the first-stage heat exchange device 1 and the second-stage heat exchange device 2, and the waste heat can still be recovered, in one embodiment, the third-stage heat exchange device 3 can be a water source heat pump unit, and the water temperature of the continuous drainage water can be further reduced.

The water source heat pump unit is a heat pump which takes water or water solution added with antifreezing agent as a low-temperature heat source; when the temperature of the continuous drainage is lower than the temperature of the heated object, the water source heat pump technology is adopted, and the water temperature of the continuous drainage can be further reduced while heating and circulating backwater is heated.

Considering that continuous drainage is continuous drainage throughout the year and is divided into heating seasons and non-heating seasons in one year, in order to realize waste heat recovery of continuous drainage throughout the year, referring to fig. 2, in an embodiment, a cascade utilization system of waste heat of continuous drainage of a power plant boiler may include: a drain pipe 100; the drainage branch pipe 200 is connected with the drainage main pipe 100, and the drainage branch pipe 200 is connected with a first-stage heat exchange device 1, a second-stage heat exchange device 2 and a third-stage heat exchange device 3; and the control valve group is used for connecting a single device in the first-stage heat exchange device 1, the second-stage heat exchange device 2 and the third-stage heat exchange device 3 or connecting more than two devices in series into the drainage branch pipe 200.

In an embodiment, optionally, the control valve group includes a stop valve M1, a stop valve M2, a stop valve M3, a stop valve M4, a stop valve M5, a stop valve M6, a stop valve M7, a stop valve M8, and a stop valve M9; the stop valves M1, M3 and M5 are used for controlling the on-off of the water inlet pipe and the water outlet connection branch pipe 200 of the high temperature side of the first-stage heat exchange device 1, the second-stage heat exchange device 2 and the third-stage heat exchange device 3 respectively; the stop valve M2, the stop valve M4 and the stop valve M6 are respectively used for controlling the on-off of a water outlet pipe at the high temperature side of the first-stage heat exchange device 1, the second-stage heat exchange device 2 and the third-stage heat exchange device 3 and the water connection and drainage branch pipe 200; the stop valve M7, the stop valve M8 and the stop valve M9 are arranged on the continuous drainage branch pipe 200 and are respectively used for controlling the on-off of a pipe section positioned between water inlet and outlet pipes of the first-stage heat exchange device 1, a pipe section positioned between water inlet and outlet pipes of the second-stage heat exchange device 2 and a pipe section positioned between water inlet and outlet pipes of the third-stage heat exchange device 3 on the continuous drainage branch pipe 200.

By arranging the stop valve M1, the stop valve M2, the stop valve M3, the stop valve M4, the stop valve M5, the stop valve M6, the stop valve M7, the stop valve M8 and the stop valve M9, smooth switching of two working conditions in a heating season and a non-heating season is ensured, for example, the first-stage heat exchange device 1, the second-stage heat exchange device 2 and the third-stage heat exchange device 3 are connected in series to be connected with the drainage branch pipe 200 in the heating season, and the second-stage heat exchange device 2 is independently connected with the drainage branch pipe 200 in the non-heating season.

In one application scenario:

referring to fig. 2 and 3, at the time of heating season, the shut-off valves M1, M2, M3, M4, M5 and M6 are opened, the shut-off valves M7, M8 and M9 are closed, and the first-stage heat exchange device 1, the second-stage heat exchange device 2 and the third-stage heat exchange device 3 are connected in series; the 130 ℃ boiler continuous drainage enters the first-stage heat exchange device 1 and 40 ℃ heating backwater to exchange heat, the continuous drainage temperature is reduced to 70 ℃ and enters the second-stage heat exchange device 2 and 10 ℃ desalted water to exchange heat, the continuous drainage temperature is reduced to 20 ℃ and enters the third-stage heat exchange device 3, the water source heat pump unit absorbs heat of the continuous drainage at 20 ℃, and the continuous drainage temperature is reduced to 10 ℃ and is discharged to a pollution discharge cooling pool; heating backwater at 40 ℃ is pressurized into the first-stage heat exchange device 1 and the third-stage heat exchange device 3 through a heating circulating pump, heated to 50 ℃ and then sent to the heating tail end; the desalted water at 10 ℃ is fed into a second stage plate heat exchanger, heated to 20 ℃ and fed into a deaerator.

Referring to fig. 2 and 4, in the non-heating season, the stop valves M7, M3, M4 and M9 are opened, the stop valves M1, M2, M5, M6 and M8 are closed, and 130 ℃ continuous water is discharged into the second stage heat exchange device 2 to exchange heat with 20 ℃ demineralized water, and the continuous water is discharged to the blowdown cooling pond after the temperature is reduced to 35 ℃; the desalted water at 20 ℃ is fed into a second stage plate heat exchanger, heated to 40 ℃ and fed into a deaerator.

In an embodiment, optionally, the first stage heat exchange device 1 and the third stage heat exchange device 3 exchange heat with the heating water pipe system 300.

In an embodiment, optionally, the first stage heat exchange device 1 and the second stage heat exchange device 2 are plate heat exchangers; the third-stage heat exchange device 3 is a water source heat pump unit.

In an embodiment, optionally, the water inlet side of the second stage heat exchange device 2 is connected to a demineralized water supply pipe, and the water outlet side is connected to a deaerator water supplementing pipe.

In an embodiment, optionally, the second stage heat exchange device 2 is used for heating the hot water tank to supplement water.

In summary, the cascade utilization system of the waste heat of the continuous drainage of the power plant boiler realizes the annual waste heat recovery of the continuous drainage of the boiler, fully utilizes the waste heat of the continuous drainage, reduces the drainage temperature of the continuous drainage to the minimum through cascade utilization of the continuous drainage, and reduces the thermal pollution to the surrounding environment; the preheating of the demineralized water supply is additionally carried out, the water temperature of the demineralized water entering the deaerator is increased, the consumption of heating steam of the deaerator is reduced, the generating capacity is increased, and the economic benefit of a power plant is improved; meanwhile, the temperature of desalted water is increased, so that uneven heating of the deaerator can be relieved, and vibration of the deaerator is reduced.

The components (components not illustrating specific structures) selected in the application are all common standard components or components known to those skilled in the art, and the structures and principles of the components are all known to those skilled in the art through technical manuals or through routine experimental methods.

In describing embodiments of the present utility model, unless explicitly stated and limited otherwise, the terms "mounted," "connected," "coupled," and "connected" are to be construed broadly, and may be, for example, fixedly coupled, detachably coupled, or integrally coupled.

In the description of the present utility model, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

With the above-described preferred embodiments according to the present utility model as an illustration, the above-described descriptions can be used by persons skilled in the relevant art to make various changes and modifications without departing from the scope of the technical idea of the present utility model. The technical scope of the present utility model is not limited to the description, but must be determined according to the scope of claims.

Claims (10)

1. A power plant boiler continuous drainage waste heat cascade utilization system, comprising:

a drain main pipe (100);

the drainage branch pipe (200) is connected with the drainage main pipe (100), and the drainage branch pipe (200) is connected with a first-stage heat exchange device (1), a second-stage heat exchange device (2) and a third-stage heat exchange device (3); wherein the method comprises the steps of

The first-stage heat exchange device (1), the second-stage heat exchange device (2) and the third-stage heat exchange device (3) are connected in series and connected with the drainage branch pipe (200).

2. The waste heat gradient utilization system according to claim 1, wherein,

the first-stage heat exchange device (1) and the third-stage heat exchange device (3) exchange heat with a heating water pipe system (300).

3. The waste heat gradient utilization system according to claim 2, wherein,

the first-stage heat exchange device (1) and the second-stage heat exchange device (2) are plate heat exchangers.

4. The waste heat gradient utilization system according to claim 1, wherein,

the water inlet side of the second-stage heat exchange device (2) is connected with a demineralized water supply pipe, and the water outlet side is connected with a deaerator water supplementing pipe.

5. The waste heat gradient utilization system according to claim 1, wherein,

the third-stage heat exchange device (3) is a water source heat pump unit.

6. A power plant boiler continuous drainage waste heat cascade utilization system, comprising:

a drain main pipe (100);

the drainage branch pipe (200) is connected with the drainage main pipe (100), and the drainage branch pipe (200) is connected with a first-stage heat exchange device (1), a second-stage heat exchange device (2) and a third-stage heat exchange device (3); and

the control valve group is used for connecting a single device in the first-stage heat exchange device (1), the second-stage heat exchange device (2) and the third-stage heat exchange device (3) or connecting more than two devices in series into the drainage branch pipe (200).

7. The waste heat gradient utilization system according to claim 6, wherein the waste heat gradient is a waste heat gradient,

the control valve group comprises a stop valve M1, a stop valve M2, a stop valve M3, a stop valve M4, a stop valve M5, a stop valve M6, a stop valve M7, a stop valve M8 and a stop valve M9; wherein the method comprises the steps of

The stop valves M1, M3 and M5 are respectively used for controlling the on-off of a water inlet pipe and a water connection and drainage branch pipe (200) at the high temperature side of the first-stage heat exchange device (1), the second-stage heat exchange device (2) and the third-stage heat exchange device (3);

the stop valve M2, the stop valve M4 and the stop valve M6 are respectively used for controlling the on-off of a water outlet pipe at the high temperature side of the first-stage heat exchange device (1), the second-stage heat exchange device (2) and the third-stage heat exchange device (3) and a water connection and drainage branch pipe (200);

the stop valve M7, the stop valve M8 and the stop valve M9 are arranged on the continuous drainage branch pipe (200) and are respectively used for controlling the on-off of a pipe section positioned between water inlet and outlet pipes of the first-stage heat exchange device (1), a pipe section positioned between water inlet and outlet pipes of the second-stage heat exchange device (2) and a pipe section positioned between water inlet and outlet pipes of the third-stage heat exchange device (3) on the continuous drainage branch pipe (200).

8. The waste heat gradient utilization system according to claim 7, wherein the waste heat gradient is set in a predetermined condition,

the first-stage heat exchange device (1) and the third-stage heat exchange device (3) exchange heat with a heating water pipe system (300).

9. The waste heat gradient utilization system according to claim 8, wherein the waste heat gradient is a waste heat gradient,

the first-stage heat exchange device (1) and the second-stage heat exchange device (2) are plate heat exchangers;

the third-stage heat exchange device (3) is a water source heat pump unit.

10. The waste heat gradient utilization system according to claim 7, wherein the waste heat gradient is set in a predetermined condition,

the water inlet side of the second-stage heat exchange device (2) is connected with a demineralized water supply pipe, and the water outlet side is connected with a deaerator water supplementing pipe.