Water heating system for boiler

Abstract

The utility model relates to a boiler water heating system, and belongs to the technical field of heat energy recovery. Comprising a heat exchanger, and an inlet and an outlet of the heat exchanger are provided with a water inlet valve and a water outlet valve respectively; the heat exchanger is provided with a flue gas inlet and a flue gas outlet; the water inlet valve is connected with the demineralized water storage tank through a pipeline; the water outlet valve is connected with the high-pressure deaerator through a pipeline, and a water return valve is arranged on the pipeline; at least one circulating pipeline is arranged between the water outlet valve and the water return valve; the circulating pipeline is connected with the water inlet valve; and an electric circulating valve and a booster pump are arranged on the circulating pipeline. According to the utility model, the flue gas discharged by the high-pressure boiler can be effectively utilized, heat in the flue gas is absorbed and used for heating demineralized water, and the steam consumption of the high-pressure deaerator is reduced, so that the aim of fully utilizing the heat of the flue gas is fulfilled.

Description

Technical Field

[0001] The utility model relates to the technical field of heat energy recovery, in particular to a boiler water heating system. Background Art

[0002] Power plant boilers are crucial energy conversion devices among the main equipment in a power plant. Their function is to convert the chemical energy of the fuel into thermal energy, using this thermal energy to heat the water within the boiler, producing superheated steam of sufficient quantity and quality (steam temperature and pressure) for use in the steam turbine. Modern thermal power plant boilers feature large capacities, high-performance parameters, complex technology, and a high level of mechanization and automation. They primarily use coal as fuel, which is pulverized before being fed into the boiler furnace to burn and release heat.

[0003] When the boiler is operating, the high-temperature flue gas generated by coal combustion, after being utilized for steam generation, still reaches a temperature of around 140°C. This exhaust gas carries a significant amount of heat, which is then cooled in the desulfurization tower before being discharged into the atmosphere. Demineralized water used in power plants is typically deionized before being injected into a high-pressure deaerator for deoxygenation. This deoxygenation process requires additional heating using a heat medium.

[0004] If the heat in the high-temperature flue gas can be used to heat the desalted water, the flue gas temperature can be lowered and the steam consumption of the high-pressure deaerator can be reduced. Utility Model Content

[0005] In response to the existing problem of insufficient utilization of heat from boiler flue gas, the present invention provides a boiler water heating system to address this issue. This system utilizes a heat exchanger installed in the flue at the front end of the flue gas dust removal device to absorb heat from the flue gas and use it to heat the desalted water, thereby reducing steam consumption in the high-pressure deaerator and fully utilizing the flue gas heat.

[0006] The technical solution of the utility model is as follows:

[0007] A boiler water heating system includes a heat exchanger, wherein the inlet and outlet of the heat exchanger are respectively provided with an inlet valve and an outlet valve; the heat exchanger is provided with a flue gas inlet and a flue gas outlet; the inlet valve is connected to a desalted water storage tank through a pipeline; the outlet valve is connected to a high-pressure deaerator through a pipeline, and a return valve is provided on the pipeline; at least one circulation pipeline is provided between the outlet valve and the return valve; the circulation pipeline is connected to the inlet valve; an electric circulation valve and a booster pump are provided on the circulation pipeline; a temperature sensor is installed in the circulation pipeline; and a temperature controller is also included, the temperature sensor is connected to the temperature controller signal, and the temperature controller is connected to the booster pump control, and when the circulating desalted water reaches a predetermined temperature, the speed is automatically adjusted.

[0008] Furthermore, a connecting pipe is provided between the desalted water storage tank and the high-pressure deaerator, and a connecting valve is provided on the connecting pipe. When the desalted water does not need to be heated or the flue gas temperature is low, the desalted water does not pass through the heat exchanger and directly enters the high-pressure deaerator. This is because the flue gas contains about 2000mg / Nm 3 If the flue gas temperature drops below the dew point, the pH of the condensed liquid can reach 2-3, which is highly corrosive and can corrode the pipes. Therefore, when the flue gas temperature is low, open the connecting valve and do not use flue gas to heat the desalted water.

[0009] Furthermore, a sewage pipe is provided on the pipeline at the front end of the water inlet valve, and a sewage valve is provided on the sewage pipe; a sewage pipe is provided at the rear end of the water outlet valve, and a sewage valve is provided on the sewage pipe.

[0010] Furthermore, a check valve is provided between the electric circulation valve and the booster pump, which can prevent uneven pressure in the pipeline caused by backflow of liquid in the pipeline.

[0011] Furthermore, a manual circulation valve is provided at the front end of the booster pump.

[0012] Furthermore, the heat exchanger is an integral spiral fin tube heat exchanger.

[0013] The working principle of this utility model is as follows: after the desalted water exits the desalted water storage tank, it enters the heat exchanger. Flue gas discharged from the boiler enters the heat exchanger, heating the desalted water while also lowering its own temperature from 140°C to 115°C. After the desalted water is heated once, it is circulated and heated through a circulation pipeline. This circulating desalted water is mixed with low-temperature desalted water from the desalted water storage tank and heated to ≥80°C. When the desalted water reaches a temperature above the set point, the temperature controller controls the booster pump to operate at a variable frequency and reduced speed, and the desalted water enters the high-pressure deaerator for deoxygenation. This completes the utilization of the flue gas waste heat.

[0014] The beneficial effects of the present invention are:

[0015] The boiler flue gas waste heat recovery device provided by the utility model can effectively utilize the flue gas discharged by the high-pressure boiler, absorb the heat in the flue gas, use it to heat the desalted water, reduce the steam consumption of the high-pressure deaerator, and achieve the purpose of fully utilizing the flue gas heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 This is a schematic diagram of the equipment connection of the present utility model.

[0018] In the figure, 1-heat exchanger, 2-water inlet valve, 3-water outlet valve, 4-flue gas inlet, 5-flue gas outlet, 6-desalted water storage tank, 7-high-pressure deaerator, 8-manual circulation valve, 9-boosting pump, 10-electric circulation valve, 11-check valve, 12-drain valve, 13-return valve, 14-connecting valve, 15-circulation pipeline. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the following will be combined with the drawings of the embodiments of the present invention to clearly and completely describe the technical solutions of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0020] The front end and the rear end mentioned in the present invention are based on the flow direction of the liquid. The device that passes through first is defined as the front end, and the device that passes through later is defined as the rear end.

[0021] Example 1

[0022] A boiler water heating system includes a heat exchanger 1, wherein the inlet and outlet of the heat exchanger 1 are respectively provided with an inlet valve 2 and an outlet valve 3; the heat exchanger 1 is provided with a flue gas inlet 4 and a flue gas outlet 5; the inlet valve 2 is connected to a desalted water storage tank 6 through a pipeline; the outlet valve 3 is connected to a high-pressure deaerator 7 through a pipeline, and a return valve 13 is provided on the pipeline; a circulation pipeline 15 is provided between the outlet valve 3 and the return valve 13; the circulation pipeline 15 is connected to the inlet valve 2; the circulation pipeline 15 is provided with an electric circulation valve 10 and a booster pump 9; a temperature sensor is installed in the circulation pipeline 15; and a temperature controller is also included, the temperature sensor is connected to the temperature controller signal, and the temperature controller is controlled by the booster pump 9, and automatically adjusts the speed when the circulating desalted water reaches a predetermined temperature.

[0023] Example 2

[0024] A boiler water heating system includes a heat exchanger 1, which is an integral spiral finned tube heat exchanger. The inlet and outlet of the heat exchanger 1 are respectively provided with an inlet valve 2 and an outlet valve 3; a connecting pipe is further provided between the desalted water storage tank 6 and the high-pressure deaerator 7, and a connecting valve 14 is provided on the connecting pipe; the heat exchanger 1 is provided with a flue gas inlet 4 and a flue gas outlet 5; the inlet valve 2 is connected to the desalted water storage tank 6 through a pipeline; the outlet valve 3 is connected to the high-pressure deaerator 7 through a pipeline, and a return valve 13 is provided on the pipeline; two circulation pipes 15 are provided between the outlet valve 3 and the return valve 13; the circulation pipe 15 is connected to the inlet valve 2; the circulation pipe An electric circulation valve 10 and a booster pump 9 are provided on the pipeline 15, a check valve 11 is provided between the electric circulation valve 10 and the booster pump 9, and a manual circulation valve 8 is provided at the front end of the booster pump 9; a temperature sensor is installed in the circulation pipeline 15; it also includes a temperature controller, the temperature sensor is connected to the temperature controller signal, and the temperature controller is controlled and connected to the booster pump 9; a connecting pipe is also provided between the desalted water storage tank 6 and the high-pressure deaerator 7, and a connecting valve 14 is provided on the connecting pipe; a sewage pipe is provided on the pipeline at the front end of the water inlet valve 2, and a sewage valve 12 is provided on the sewage pipe; a sewage pipe is provided at the rear end of the water outlet valve 3, and a sewage valve 12 is provided on the sewage pipe.

[0025] Although the present invention has been described in detail with reference to the accompanying drawings and in conjunction with preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, persons of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall fall within the scope of the present invention. Any changes or substitutions that can be easily conceived by persons skilled in the art within the technical scope disclosed in the present invention shall fall within the scope of protection of the present invention.

Claims

1. A boiler water heating system, comprising a heat exchanger, wherein the inlet and outlet of the heat exchanger are respectively provided with a water inlet valve and a water outlet valve; the heat exchanger is provided with a flue gas inlet and a flue gas outlet; characterized in that: The water inlet valve is connected to the desalted water storage tank through a pipeline; the water outlet valve is connected to the high-pressure deaerator through a pipeline, and a return valve is provided on the pipeline; at least one circulation pipeline is provided between the water outlet valve and the return valve; the circulation pipeline is connected to the water inlet valve; an electric circulation valve and a booster pump are provided on the circulation pipeline, and a temperature sensor is installed in the circulation pipeline; a temperature controller is also included, the temperature sensor is connected to the temperature controller signal, and the temperature controller is connected to the booster pump control.

2. A boiler water heating system according to claim 1, characterized in that: A connecting pipe is further provided between the desalted water storage tank and the high-pressure deaerator, and a connecting valve is provided on the connecting pipe.

3. A boiler water heating system according to claim 1, characterized in that: A sewage pipe is provided on the pipeline at the front end of the water inlet valve, and a sewage valve is provided on the sewage pipe; a sewage pipe is provided on the rear end of the water outlet valve, and a sewage valve is provided on the sewage pipe.

4. A boiler water heating system according to claim 1, characterized in that: A check valve is provided between the electric circulation valve and the booster pump.

5. A boiler water heating system according to claim 1, characterized in that: A manual circulation valve is provided at the front end of the booster pump.

6. A boiler water heating system according to claim 1, characterized in that: The heat exchanger is an integral spiral fin tube heat exchanger.

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