An emergency boiler standby device for a gas-steam combined cycle unit

Abstract

The utility model belongs to gas -vapor combined cycle power generation and heating technical field, concretely relates to an emergency furnace heat backup device for gas -vapor combined cycle unit, including upper drum, the upper drum is connected with the upper end of water cooled wall and is arranged, and the lower end of water cooled wall is connected with lower drum and is arranged, and the water outlet pipe is connected with the cold medium inlet of heat exchanger through the pipeline with one manual stop valve, water pump, two manual stop valves, and the cold medium outlet of heat exchanger is connected with the upper end of upper drum through the pipeline with three manual stop valves, and the hot medium inlet of heat exchanger is connected with the original continuous blowdown pipe of waste heat boiler through the pipeline with four manual stop valves, and the hot medium outlet of heat exchanger is connected with fixed discharge pipe through the pipeline. The utility model can keep the water temperature of emergency furnace in high temperature state by hot water in the continuous blowdown pipe of waste heat boiler, realizes the purpose of high temperature heat backup of emergency furnace.

Description

Technical Field

[0001] This utility model belongs to the field of gas-steam combined cycle power generation and heating technology, specifically relating to an emergency boiler heat backup device for gas-steam combined cycle units. Background Technology

[0002] Gas-fired combined cycle (Gas-Steam Combined Cycle) power generation and heating units play a vital role in providing heating services, and this service is characterized by its uninterrupted nature. This is especially true when the units are supplying heating to industrial parks, as interruptions could lead to significant losses for heat users. However, Gas-fired combined cycle units are susceptible to sudden malfunctions and loss of heating capacity. Therefore, it is essential to construct emergency boilers to support these units. This ensures that when the Gas-Steam Combined Cycle unit is unable to provide heating in an emergency, the emergency boiler can be quickly activated to produce steam and meet the needs of heat users. To enable the emergency boiler to produce steam rapidly in an emergency, it needs to be kept in a hot standby state at all times (meaning that if the emergency boiler is cold, it will be unable to produce steam for a short period). Currently, the method for keeping the emergency boiler in hot standby state is to periodically heat it with natural gas. Specifically, when the water temperature in the emergency boiler falls below a lower limit, the burner is activated to supply natural gas for combustion; when the water temperature rises above the upper limit, the burner shuts down, and the emergency boiler enters a high-temperature standby state. This emergency boiler hot standby method consumes an average of 1,000 yuan of natural gas per day, which is a problem of high hot standby cost. Moreover, the operation procedures are complicated, which greatly increases the workload of the operators. Utility Model Content

[0003] This invention provides an emergency boiler hot standby device for gas-steam combined cycle units to address the above-mentioned problems.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: An emergency boiler hot standby device for a gas-steam combined cycle unit includes an upper boiler drum, which is connected to the upper end of a water-cooled wall, and the lower end of the water-cooled wall is connected to a lower boiler drum. A water outlet pipe is connected to the lower boiler drum. The water outlet pipe is connected to the cold medium inlet of a heat exchanger via a pipeline equipped with a No. 1 manual shut-off valve, a water pump, and a No. 2 manual shut-off valve. The cold medium outlet of the heat exchanger is connected to the upper end of the upper boiler drum via a pipeline equipped with a No. 3 manual shut-off valve. The hot medium inlet of the heat exchanger is connected to the existing waste heat boiler continuous blowdown pipe via a pipeline equipped with a No. 4 manual shut-off valve. The hot medium outlet of the heat exchanger is connected to a fixed discharge pipe via a pipeline.

[0005] Furthermore, the outlet pipe is connected to the fixed discharge pipe through a pipeline equipped with a No. 5 manual shut-off valve.

[0006] Furthermore, the water outlet pipe is located at the lower end of the lower boiler drum.

[0007] Furthermore, an adjustment pipeline is provided between the rear end of the No. 2 manual shut-off valve and the rear end of the No. 3 manual shut-off valve. An electric adjustment valve is installed on the adjustment pipeline. A temperature sensor is installed on the pipeline between the No. 3 manual shut-off valve and the upper drum. The water pump, the electric adjustment valve, and the temperature sensor are all electrically connected to the controller.

[0008] Furthermore, a second electric regulating valve and a second temperature sensor are installed on the pipeline between the heat medium outlet of the heat exchanger and the fixed-flow pipe. Both the second electric regulating valve and the second temperature sensor are electrically connected to the controller.

[0009] Furthermore, the water pump is a variable frequency water pump.

[0010] Compared with the prior art, the present invention has the following advantages: 1. This utility model utilizes hot water from the continuous blowdown pipe of a waste heat boiler to maintain the water temperature of the emergency boiler at a high level. The specific principle is as follows: Boiler water in the water-cooled wall of the emergency boiler is drawn from the lower left side of the lower drum, pressurized by a water pump, and enters the heat exchanger. Hot water from the continuous blowdown pipe of the waste heat boiler enters the heat exchanger from the other side and exchanges heat with the boiler water. After absorbing heat, the boiler water flows out of the heat exchanger and returns to the upper right side of the upper drum along the pipeline. Then, it flows slowly along the upper drum, water-cooled wall, and lower drum, from the upper right corner of the upper drum to the lower left corner of the lower drum, and flows out from the outlet pipe, entering the next cycle. The high-temperature hot water, after exchanging heat with the boiler water, is discharged from the heat exchanger and enters the fixed discharge pipe for recycling. In this way, the boiler water is continuously heated to the set value in the heat exchanger, thereby maintaining the temperature of the emergency boiler at a high level and achieving the purpose of high-temperature hot standby for emergency boilers.

[0011] 2. This invention involves taking boiler water from the outlet pipe connected to the lower left side of the lower boiler drum for heating, and then returning the heated boiler water to a high temperature from the upper right side of the upper boiler drum. The water intake and return points are diagonally positioned, ensuring all boiler water circulates without short circuits or dead zones. This not only promotes uniform heating of the water-cooled walls but also allows for the removal of the coldest boiler water, thereby increasing the heat exchanger's temperature difference and optimizing the heat exchange effect.

[0012] 3. This invention can cool high-temperature hot water entering a heat exchanger to a lower level. Specifically, temperature sensor number two measures the temperature of the hot water after heat exchange. If this temperature exceeds a set value, the opening of electric regulating valve number two is automatically reduced, extending the residence time of the hot water within the heat exchanger and allowing for better cooling by the boiler water. The hot water is discharged from the heat exchanger only after its design temperature has been reached. This achieves precise temperature control of the hot water, facilitating maximum heat recovery.

[0013] 4. This utility model can heat the boiler water to a set value. Specifically, the first temperature sensor measures the temperature of the heated boiler water. If this temperature is higher than the set value, the opening of the first electric regulating valve is automatically increased, thus reducing the amount of boiler water entering the heat exchanger while increasing the flow rate of cold boiler water through the regulating pipe, resulting in a lower temperature of the mixed boiler water. Conversely, if the temperature measured by the first temperature sensor is lower than the set value, the opening of the first electric regulating valve is automatically decreased, increasing the amount of boiler water entering the heat exchanger while decreasing the flow rate of cold boiler water through the regulating pipe, resulting in a higher temperature of the mixed boiler water. In extreme cases, where the first electric valve is fully closed but the temperature measured by the first temperature sensor is still lower than the set value, the pump frequency is increased, increasing the flow rate of boiler water entering the heat exchanger. This enhances the cooling effect of the high-temperature hot water, lowering its temperature. Then, the opening of the second electric regulating valve is automatically increased, further increasing the flow rate of high-temperature hot water entering the heat exchanger, thus increasing the heat absorbed by the boiler water and raising its temperature; the reverse is also true.

[0014] 5. This utility model has good economic benefits. Specifically: ① The heat source for heating the boiler water is the high-temperature wastewater discharged from the waste heat boiler. The heat contained in this hot water was originally wasted, but this utility model uses this wastewater to heat the boiler water, realizing heat recovery and utilization, and achieving good economic benefits; ② After adopting the technical solution of this utility model, it is no longer necessary to use natural gas to heat the emergency boiler, saving a large amount of natural gas; ③ The temperature of the high-temperature hot water discharged from the heater has been reduced to a very low temperature, achieving maximum energy saving. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model; In the diagram, 1 is the upper boiler drum, 2 is the water-cooled wall, 3 is the lower boiler drum, 4 is the water outlet pipe, 5 is the first manual shut-off valve, 6 is the water pump, 7 is the second manual shut-off valve, 8 is the heat exchanger, 9 is the third manual shut-off valve, 10 is the fourth manual shut-off valve, 11 is the waste heat boiler continuous blowdown pipe, 12 is the fixed blowdown pipe, 13 is the fifth manual shut-off valve, 14 is the regulating pipeline, 15 is the first electric regulating valve, 16 is the first temperature sensor, 17 is the controller, 18 is the second electric regulating valve, and 19 is the second temperature sensor. Detailed Implementation

[0016] To further illustrate the technical solution of this utility model, the following embodiments will be used to further explain this utility model.

[0017] like Figure 1 As shown, an emergency boiler hot standby device for a gas-steam combined cycle unit includes an upper boiler drum 1, which is connected to the upper end of a water-cooled wall 2. The lower end of the water-cooled wall 2 is connected to a lower boiler drum 3. A water outlet pipe 4 is connected to the lower end of the lower boiler drum 3. The water outlet pipe 4 is connected to a fixed discharge pipe 12 through a pipeline with a No. 5 manual shut-off valve 13. The water outlet pipe 4 is connected to the cold medium inlet of a heat exchanger 8 through a pipeline with a No. 1 manual shut-off valve 5, a water pump 6, and a No. 2 manual shut-off valve 7. The cold medium outlet of the heat exchanger 8 is connected to the upper end of the upper boiler drum 1 through a pipeline with a No. 3 manual shut-off valve 9. The hot medium inlet of the heat exchanger 8 is connected to the existing waste heat boiler continuous blowdown pipe 11 through a pipeline with a No. 4 manual shut-off valve 10. The hot medium outlet of the heat exchanger 8 is connected to the fixed discharge pipe 12 through a pipeline.

[0018] A regulating pipe 14 is provided between the rear end of the second manual shut-off valve 7 and the rear end of the third manual shut-off valve 9. A first electric regulating valve 15 is installed on the regulating pipe 14. A first temperature sensor 16 is installed on the pipe between the third manual shut-off valve 9 and the upper boiler drum 1. The water pump 6, the first electric regulating valve 15, and the first temperature sensor 16 are all electrically connected to the controller 17. A second electric regulating valve 18 and a second temperature sensor 19 are provided on the pipe between the heat medium outlet of the heat exchanger 8 and the fixed discharge pipe 12. Both the second electric regulating valve 18 and the second temperature sensor 19 are electrically connected to the controller 17. The water pump 6 is a variable frequency water pump.

[0019] The foregoing has shown and described the main features and advantages of this utility model. It will be apparent to those skilled in the art that this utility model is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description, and thus all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this utility model.

[0020] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An emergency boiler hot standby device for a gas-steam combined cycle unit, characterized in that: The system includes an upper boiler drum (1), which is connected to the upper end of a water-cooled wall (2). The lower end of the water-cooled wall (2) is connected to a lower boiler drum (3). A water outlet pipe (4) is connected to the lower boiler drum (3). The water outlet pipe (4) is connected to the cold medium inlet of the heat exchanger (8) through a pipeline with a first manual shut-off valve (5), a water pump (6), and a second manual shut-off valve (7). The cold medium outlet of the heat exchanger (8) is connected to the upper end of the upper boiler drum (1) through a pipeline with a third manual shut-off valve (9). The hot medium inlet of the heat exchanger (8) is connected to the existing waste heat boiler continuous blowdown pipe (11) through a pipeline with a fourth manual shut-off valve (10). The hot medium outlet of the heat exchanger (8) is connected to the fixed discharge pipe (12) through a pipeline.

2. The emergency boiler hot standby device for a gas-steam combined cycle unit according to claim 1, characterized in that: The outlet pipe (4) is connected to the fixed drain pipe (12) through a pipeline with a No. 5 manual shut-off valve (13).

3. An emergency boiler hot standby device for a gas-steam combined cycle unit according to claim 2, characterized in that: The water outlet pipe (4) is located at the lower end of the lower boiler drum (3).

4. An emergency boiler hot standby device for a gas-steam combined cycle unit according to claim 1, characterized in that: A regulating pipeline (14) is provided between the rear end of the second manual shut-off valve (7) and the rear end of the third manual shut-off valve (9). An electric regulating valve (15) is installed on the regulating pipeline (14). A temperature sensor (16) is provided on the pipeline between the third manual shut-off valve (9) and the upper drum (1). The water pump (6), the electric regulating valve (15) and the temperature sensor (16) are all electrically connected to the controller (17).

5. An emergency boiler hot standby device for a gas-steam combined cycle unit according to claim 4, characterized in that: A second electric regulating valve (18) and a second temperature sensor (19) are installed on the pipeline between the heat medium outlet of the heat exchanger (8) and the fixed pipe (12). The second electric regulating valve (18) and the second temperature sensor (19) are both electrically connected to the controller (17).

6. An emergency boiler hot standby device for a gas-steam combined cycle unit according to claim 1, characterized in that: The water pump (6) is a variable frequency water pump.

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