Waste heat utilization system for blow-down water of boiler periodic blowdown flash tank

Abstract

The utility model relates to a boiler periodic blowdown flash tank blowdown water waste heat utilization system which comprises a heat exchanger set, the input end of the heat exchanger set is connected with a waste heat water input pipeline and a cooling water input pipeline, the output end of the heat exchanger set is connected with a hot water output pipeline and a waste water pipeline, and the waste water pipeline is connected to a blowdown cooling pool. The waste heat water input pipeline is connected with the heat exchanger set, a parallel drain pipe directly led to the pollution discharge cooling pool is further led out, and one of the parallel drain pipe and the heat exchanger set is selected at a time. According to the utility model, a heat exchange system is additionally arranged before the waste water with heat energy is discharged into the pollution discharge cooling pool, so that the heat energy is recovered, and the consumption of industrial cooling water is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of power plant wastewater heat energy recovery, in particular to a boiler fixed-discharge expansion tank wastewater waste heat utilization system. Background Art

[0002] The wastewater separated from the fixed-discharge expansion tanks of power plant boilers carries a certain amount of thermal energy. Conventional designs discharge this thermally charged wastewater directly into a sewage cooling tank. However, due to the high thermal energy and temperature, industrial cooling water is often added to the sewage cooling tank to cool it down before it is discharged into the plant's wastewater network. This results in a waste of thermal energy and industrial cooling water. Utility Model Content

[0003] In response to the shortcomings of the above-mentioned existing production technology, the applicant provides a rationally structured boiler fixed-discharge expansion tank wastewater waste heat utilization system. Before discharging the wastewater with thermal energy into the sewage cooling pool, a heat exchange system is added to recover heat energy and reduce the use of industrial cooling water.

[0004] The technical solutions adopted in this utility model are as follows:

[0005] A waste heat utilization system for wastewater from a boiler fixed-discharge expansion tank includes a heat exchanger group, the input end of which is connected to a waste hot water input pipeline and a cooling water input pipeline, and the output end of which is connected to a hot water output pipeline and a wastewater pipeline, and the wastewater pipeline is connected to a wastewater cooling pool.

[0006] In addition to connecting the heat exchanger group, the waste hot water input pipeline also leads to a parallel drainage pipe that directly leads to the sewage cooling pool. Either the parallel drainage pipe or the heat exchanger group is selected at a time.

[0007] As a further improvement of the above technical solution:

[0008] A fixed-discharge sewage pump is connected in parallel to the waste hot water input pipeline, and one of the fixed-discharge sewage pumps is operated at a time.

[0009] The output ends of the fixed sewage pump of the waste hot water input pipeline are respectively led to the sewage cooling tank and the heat exchanger group.

[0010] A drainage valve group is provided between the waste water input pipeline and the waste water pipeline output by the heat exchanger group.

[0011] A cold water tank is provided on the cooling water input pipeline, a cooling water valve group is provided between the cooling water source and the cold water tank, and a water supply pump group is connected between the cold water tank and the heat exchanger group.

[0012] Valves are provided on both the input and output sides of a single fixed-discharge sewage pump and a single water supply pump.

[0013] The heat exchanger group operates one at a time.

[0014] The usable hot water output by the heat exchanger group is transported to the hot water storage tank, and the waste water output by the heat exchanger group is discharged into the sewage cooling pool.

[0015] The beneficial effects of the utility model are as follows:

[0016] The utility model is applied in power plants, adopting a waste heat utilization system of sewage from a fixed-discharge expansion tank, utilizing the waste heat of the fixed-discharge sewage to exchange cold water into hot water for external supply, thereby reducing the heat loss of the sewage from the fixed-discharge expansion tank, lowering the temperature of the sewage entering the sewage cooling pool, and reducing the amount of industrial cooling water used for mixing and cooling.

[0017] In the present invention, not all waste hot water must pass through the heat exchanger group. A branch is reserved to flow directly into the sewage cooling pool. If the heat energy in the waste hot water is not much, it does not need to pass through the heat exchanger group for heat exchange, thereby achieving efficient, optional and energy-saving drainage. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall system of the present utility model.

[0019] Figure 2 This is a flowchart of the waste hot water treatment process of the present utility model.

[0020] Among them: 1. Cooling water input pipeline; 2. Waste water input pipeline; 3. Waste water pipeline; 4. Hot water output pipeline; 5. Sewage cooling pool; 6. Heat exchanger group;

[0021] 201. Fixed sewage pump; 202. Drain valve group;

[0022] 101. Cooling water valve group; 102. Make-up water pump group; 103. Cold water tank;

[0023] 301. Parallel drainage pipes. DETAILED DESCRIPTION

[0024] The specific implementation of the present utility model will be described below with reference to the accompanying drawings.

[0025] like Figure 1 and Figure 2 As shown, the waste heat utilization system of the boiler fixed discharge expansion tank of this embodiment includes a heat exchanger group 6. The input end of the heat exchanger group 6 is connected to the waste hot water input pipeline 2 and the cooling water input pipeline 1. The output end of the heat exchanger group 6 is connected to the hot water output pipeline 4 and the waste water pipeline 3. The waste water pipeline 3 is connected to the sewage cooling pool 5.

[0026] In addition to being connected to the heat exchanger group 6, the waste hot water input pipeline 2 also leads to a parallel drainage pipe 301 directly leading to the sewage cooling pool 5. Either the parallel drainage pipe 301 or the heat exchanger group 6 is selected at a time.

[0027] A fixed-discharge sewage pump 201 is connected in parallel to the waste hot water input pipeline 2, and one of the fixed-discharge sewage pumps 201 is operated at a time.

[0028] The output end of the fixed sewage pump 201 of the waste heat input pipeline 2 is respectively led to the sewage cooling tank 5 and the heat exchanger group 6.

[0029] A drainage valve group 202 is provided between the waste water input pipeline 2 and the waste water pipeline 3 outputted from the heat exchanger group 6 .

[0030] A cold water tank 103 is provided on the cooling water input pipeline 1 , a cooling water valve group 101 is provided between the cooling water source and the cold water tank 103 , and a water supply pump group 102 is connected between the cold water tank 103 and the heat exchanger group 6 .

[0031] Valves are provided on both the input side and the output side of the single fixed-discharge sewage pump 201 and the single water supply pump.

[0032] One of the heat exchanger groups 6 is operated at a time.

[0033] The usable hot water output by the heat exchanger group 6 is transported to the hot water storage tank, and the waste water output by the heat exchanger group 6 is discharged into the sewage cooling pool 5.

[0034] The overall structure and working principle of the utility model are as follows:

[0035] like Figure 1 As shown, the waste hot water from the fixed discharge expansion tank is connected to two parallel fixed discharge sewage pumps 201, one of which is in use and the other is in standby. The outlet of the fixed discharge sewage pump 201 is divided into two routes, one of which is connected to the heat exchanger group 6, and the heat exchanger is one in use and one in standby; the other route is directly connected to the sewage cooling pool 5; the sewage after heat exchange and cooling in the heat exchanger is then discharged to the sewage cooling pool 5, that is, the waste hot water can be discharged directly or discharged after heat exchange.

[0036] At the same time, a regulating valve is provided on the pipeline before the heat exchanger group 6 to adjust the amount of water entering the heat exchanger so as to adjust the heat load; the cooling water used for heat exchange first passes through the cooling water input pipeline 1 to replenish the cold water tank, and then is sent to the heat exchanger group 6 through the water replenishment pump group 102 for heat exchange and temperature rise. The hot water after heat exchange and temperature rise enters the hot water storage tank for buffering and external supply or sale.

[0037] like Figure 2 As shown, when the waste hot water needs to be discharged, first consider whether the water temperature of the waste hot water needs to be heat exchanged. If the water temperature is low, it can be discharged directly, and then directly discharged into the sewage cooling pool 5 through the parallel drainage pipe 301.

[0038] If the water temperature is high and contains more heat energy, it will flow in from the waste hot water input pipeline 2, and flow through the fixed sewage pump 201 and the heat exchanger group 6 in sequence; the heat exchanger group 6 also introduces cooling water from the cooling water input pipeline 1. After the cooling water and the waste hot water exchange heat, the waste hot water that has lost heat energy flows into the sewage cooling pool 5. The cooling water after heat exchange is input into the hot water storage tank for buffering, and the hot water in the hot water storage tank is supplied for external use.

[0039] The utility model is put into practical use. Taking a 130t / h boiler in a northern power plant as an example, the discharge rate is calculated as 2% under the condition of only considering the normal discharge of the boiler, and considering the drainage and emergency water discharge of part of the boiler, the sewage volume is 3t / h. If a fixed-discharge expansion tank sewage waste heat utilization system is used on the unit to utilize waste heat to supply hot water, according to the sewage temperature of the fixed-discharge expansion tank being 80℃, the water temperature after drainage heat exchange being 50℃, the water inlet temperature of the heat exchanger being 30℃, and the water outlet temperature being 50℃, the external hot water that can be generated is about 4.5t / h. This part of the hot water can be supplied externally. The use of this waste heat utilization system can save a considerable part of the heat of the sewage.

[0040] The above description is an explanation of the utility model, not a limitation of the utility model. The scope of the utility model is defined by the claims. Any form of modification can be made within the scope of protection of the utility model.

Claims

1. A system for utilizing waste heat from wastewater discharged from a boiler fixed discharge expansion tank, characterized in that: The heat exchanger comprises a heat exchanger group (6), wherein the input end of the heat exchanger group (6) is connected to a waste hot water input pipeline (2) and a cooling water input pipeline (1), and the output end of the heat exchanger group (6) is connected to a hot water output pipeline (4) and a waste water pipeline (3), and the waste water pipeline (3) is connected to a sewage cooling pool (5). In addition to being connected to the heat exchanger group (6), the waste hot water input pipeline (2) also leads to a parallel drainage pipe (301) that is directly led to the sewage cooling pool (5). Either the parallel drainage pipe (301) or the heat exchanger group (6) is selected at a time.

2. The boiler fixed discharge expansion tank wastewater waste heat utilization system according to claim 1, characterized in that: A fixed-discharge sewage pump (201) is connected in parallel to the waste heat water input pipeline (2), and one of the fixed-discharge sewage pumps (201) is operated at a time.

3. The system for utilizing waste heat from wastewater discharged from a boiler fixed discharge expansion tank according to claim 2, characterized in that: The output end of the fixed sewage pump (201) of the waste water input pipeline (2) is respectively led to the sewage cooling pool (5) and the heat exchanger group (6).

4. The boiler fixed discharge expansion tank wastewater waste heat utilization system according to claim 1, characterized in that: A drainage valve group (202) is provided between the waste water input pipeline (2) and the waste water pipeline (3) output from the heat exchanger group (6).

5. The boiler fixed discharge expansion tank wastewater waste heat utilization system according to claim 1, characterized in that: A cold water tank (103) is provided on the cooling water input pipeline (1), a cooling water valve group (101) is provided between the cooling water source and the cold water tank (103), and a water supply pump group (102) is connected between the cold water tank (103) and the heat exchanger group (6).

6. The boiler fixed-discharge expansion tank wastewater waste heat utilization system according to claim 2 or claim 5, characterized in that: Valves are provided on the input side and the output side of the single fixed-discharge sewage pump (201) and the single water supply pump.

7. The boiler fixed discharge expansion tank wastewater waste heat utilization system according to claim 1, characterized in that: One of the heat exchanger groups (6) is operated at a time.

8. The system for utilizing waste heat from wastewater of a boiler fixed discharge expansion tank according to claim 7, characterized in that: The usable hot water outputted by the heat exchanger group (6) is transported to the hot water storage tank, and the waste water outputted by the heat exchanger group (6) is discharged into the sewage cooling pool (5).

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