Turbo flue gas waste heat power generation system with improved thermal efficiency

Abstract

This utility model discloses a turbine flue gas waste heat power generation system with improved thermal efficiency, including a boiler, a variable frequency booster pump, a liquid storage tank, a turbine expander, a primary heat exchanger, a secondary heat exchanger, and a waste heat recovery steam generator. The liquid storage tank is provided with a working fluid return port and a low-temperature working fluid outlet. The working fluid return port is connected to the working fluid side inlet of the primary heat exchanger through a first connecting pipe, and the low-temperature working fluid outlet is connected to the working fluid inlet of the waste heat recovery steam generator through a pipe. The boiler's main exhaust pipe is connected in series with the heat source side of the primary heat exchanger and the heat source side of the secondary heat exchanger. The steam outlet of the waste heat recovery steam generator is connected in parallel to the inlet pipe of the variable frequency booster pump, forming a working fluid confluence structure with the output end of the steam filter. In this way, waste heat from the flue gas is extracted, the temperature and pressure of the working fluid steam are increased, and the turbine expander obtains more energy, thereby improving the working efficiency.

Description

Technical Field

[0001] This utility model relates to the field of turbine flue gas waste heat power generation systems, and in particular to a turbine flue gas waste heat power generation system with improved thermal efficiency. Background Technology

[0002] In industrial production, the temperature of flue gas generated after boiler combustion is typically between 110℃ and 170℃. Directly discharging the waste heat carried by this flue gas would result in significant energy waste. Current flue gas waste heat power generation systems mostly employ single-stage heat exchangers to recover heat, which has the following shortcomings: First, the heat exchange efficiency is limited, failing to fully extract heat from the flue gas, leading to insufficient heating temperature of the working fluid and low working efficiency of the turbine expander; second, the low-temperature working fluid discharged from the storage tank is not effectively utilized, resulting in serious heat waste; and third, the heat exchange structure is simple, making it difficult to dynamically adjust the heat exchange effect according to flue gas temperature fluctuations, resulting in unstable overall system thermal efficiency.

[0003] Later, a turbine flue gas waste heat power generation system was disclosed on the market. It achieved flue gas waste heat power generation through the cooperation of components such as steam filter, variable frequency booster pump, and turbine expander. However, in its single-stage heat exchange mode, the working fluid temperature increase was limited, and the working fluid discharged from the storage tank was directly returned to the circulation pipeline without secondary heat recovery, resulting in low system thermal efficiency.

[0004] Therefore, a new technical solution needs to be researched to address the above problems. Utility Model Content

[0005] In view of this, the present invention addresses the deficiencies of existing technologies, and its main objective is to provide a turbine flue gas waste heat power generation system with improved thermal efficiency. This system utilizes a design with a primary heat exchanger, a secondary heat exchanger, and a waste heat recovery steam generator. The boiler's main exhaust pipe is connected in series with the heat source side of the primary heat exchanger and the heat source side of the secondary heat exchanger. The working fluid side outlet of the primary heat exchanger is connected in series with the working fluid side inlet of the secondary heat exchanger. The working fluid side outlet of the secondary heat exchanger is connected to the inlet pipe of the steam filter. Thus, the added multi-stage heat exchangers can further extract waste heat from the flue gas before the steam filter, increasing the temperature and pressure of the working fluid steam, allowing the turbine expander to obtain more energy, thereby improving its working efficiency. Furthermore, the waste heat recovery steam generator utilizes the waste heat of the low-temperature working fluid in the storage tank to generate steam again, forming a secondary cycle, reducing heat waste, and further improving the system's thermal efficiency.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A turbine flue gas waste heat power generation system with improved thermal efficiency includes a boiler, a variable frequency booster pump, a liquid storage tank, and a turbine expander. The boiler is connected to the input end of a steam filter via a flue gas waste heat circulation pipeline. The output end of the steam filter is connected to the input end of the variable frequency booster pump. The output end of the variable frequency booster pump is connected to the input end of the turbine expander. The output end of the turbine expander is connected to the liquid storage tank, and the output end of the liquid storage tank is connected to the flue gas waste heat circulation pipeline to form a loop.

[0008] The turbine flue gas waste heat power generation system with improved thermal efficiency also includes a primary heat exchanger, a secondary heat exchanger, and a waste heat recovery steam generator.

[0009] The liquid storage tank is provided with a working fluid reflux port and a low-temperature working fluid outlet. The working fluid reflux port is connected to the working fluid side inlet of the first-stage heat exchanger through a first connecting pipe, and the low-temperature working fluid outlet is connected to the working fluid inlet of the waste heat recovery steam generator through a second connecting pipe.

[0010] The boiler's main exhaust pipe is connected in series with the heat source side of the primary heat exchanger and the heat source side of the secondary heat exchanger. The working fluid side outlet of the primary heat exchanger is connected in series with the working fluid side inlet of the secondary heat exchanger. The working fluid side outlet of the secondary heat exchanger is connected to the inlet pipe of the steam filter.

[0011] The steam outlet of the waste heat recovery steam generator is connected in parallel to the inlet pipe of the variable frequency booster pump through a connecting pipe, so that it forms a working fluid manifold structure with the output end of the steam filter.

[0012] As a preferred embodiment, a one-way valve is installed on the connecting pipeline to prevent the working fluid from flowing back into the storage tank.

[0013] As a preferred embodiment, the output end of the turbine expander is connected to a DC generator set, the shaft of the turbine expander is connected to the shaft of the DC generator set, and a fully intelligent control box with strong magnetic field protection is also provided on the side of the turbine expander. The DC generator set is connected to the fully intelligent control box with strong magnetic field protection via a cable with strong magnetic field protection.

[0014] As a preferred embodiment, a temperature sensor is installed at the bearing of the turboexpander. The temperature sensor is connected to the input terminal of the anti-magnetic fully intelligent control cabinet via a signal line to monitor the bearing temperature in real time. When the temperature exceeds the threshold, the control cabinet automatically starts the cooling system or adjusts the unit's operating parameters to prevent the bearing from overheating and being damaged.

[0015] As a preferred embodiment, a braking mechanism is installed at the rear of the DC generator set. A smoke sensor and a temperature flame detector are also installed on the side of the DC generator set and the turbine expander. The smoke sensor and the temperature flame detector are electrically connected to the anti-magnetic fully intelligent control cabinet and linked with the control circuit of the braking mechanism. When the detector detects that the smoke concentration exceeds the threshold or the temperature flame is abnormal, it sends an electrical signal to the control box. After receiving the signal, the PLC controller in the control box immediately outputs a high-level signal to the electromagnetic coil of the braking mechanism. The electromagnetic force attracts the armature, which drives the friction plate to clamp the brake disc, thereby realizing an emergency stop.

[0016] As a preferred embodiment, the braking mechanism is an electromagnetic brake, which is installed at the end of the shaft of the DC generator set, or on the drive shaft of the turbine expander and the DC generator set.

[0017] Compared with the prior art, this utility model has significant advantages and beneficial effects. Specifically, as can be seen from the above technical solution, it mainly involves the design of a primary heat exchanger, a secondary heat exchanger, and a waste heat recovery steam generator. The main flue gas pipeline of the boiler is connected in series with the heat source side of the primary heat exchanger and the heat source side of the secondary heat exchanger. The working fluid side outlet of the primary heat exchanger is connected in series with the working fluid side inlet of the secondary heat exchanger. The working fluid side outlet of the secondary heat exchanger is connected to the inlet pipeline of the steam filter. In this way, the added multi-stage heat exchangers can further extract the waste heat of the flue gas before the steam filter, increase the temperature and pressure of the working fluid steam, and enable the turbine expander to obtain more energy, thereby improving the working efficiency. Secondly, the waste heat recovery steam generator uses the waste heat of the low-temperature working fluid in the storage tank to generate steam again, forming a secondary cycle, reducing heat waste, and further improving the thermal efficiency of the system.

[0018] To more clearly illustrate the structural features and effects of this utility model, the following detailed description of this utility model is provided in conjunction with the accompanying drawings and specific embodiments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the connection structure and process flow of an embodiment of this utility model;

[0020] Figure 2 This is a control block diagram of an embodiment of the present utility model.

[0021] Explanation of reference numerals in the attached diagram:

[0022] 1. Boiler 2. Variable frequency booster pump

[0023] 3. Liquid storage tank 31. Working fluid return port

[0024] 32. Cryogenic working fluid outlet; 33. First connecting pipeline

[0025] 34. Second connecting pipeline; 4. Turbine expander

[0026] 5. Flue gas waste heat circulation pipeline; 6. Primary heat exchanger

[0027] 7. Secondary heat exchanger

[0028] 8. Waste heat recovery steam generator; 81. Connecting pipelines

[0029] 82. One-way valve; 9. DC generator set

[0030] 10. Anti-magnetic fully intelligent control box 11. Temperature sensor

[0031] 12. Braking mechanism 13. Smoke sensor

[0032] 14. Temperature flame detector. Detailed Implementation

[0033] Please refer to Figures 1 to 2 As shown, it illustrates the specific structure of an embodiment of the present invention.

[0034] In the description of this utility model, it should be noted that the directional terms such as "up", "down", "front", "back", "left", and "right" indicate the orientation and positional relationship based on the accompanying drawings or the orientation or positional relationship shown when wearing and using the device normally. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this utility model.

[0035] A turbine flue gas waste heat power generation system with improved thermal efficiency includes a boiler 1, a variable frequency booster pump 2, a liquid storage tank 3, and a turbine expander 4.

[0036] The boiler 1 is connected to the input end of the steam filter via the flue gas waste heat circulation pipeline 5; the output end of the steam filter is connected to the input end of the variable frequency booster pump 2; the output end of the variable frequency booster pump 2 is connected to the input end of the turbine expander 4; the output end of the turbine expander 4 is connected to the liquid storage tank 3; and the output end of the liquid storage tank 3 is connected to the flue gas waste heat circulation pipeline 5 to form a loop.

[0037] The turbine flue gas waste heat power generation system with improved thermal efficiency also includes a primary heat exchanger 6, a secondary heat exchanger 7, and a waste heat recovery steam generator 8. In this embodiment, both the primary heat exchanger 6 and the secondary heat exchanger 7 are plate heat exchangers with corrugated flow channels on the surface of the plates. The working fluid side and the heat source side of each heat exchanger are connected to the pipeline through flanges.

[0038] The liquid storage tank 3 is provided with a working fluid reflux port 31 and a low-temperature working fluid outlet 32. The working fluid reflux port 31 is connected to the working fluid side inlet of the first-stage heat exchanger 6 through a first connecting pipe 33, and the low-temperature working fluid outlet 32 ​​is connected to the working fluid inlet of the waste heat recovery steam generator 8 through a second connecting pipe 34.

[0039] The main exhaust pipe of the boiler 1 is connected in series with the heat source side of the primary heat exchanger 6 and the heat source side of the secondary heat exchanger 7. The working fluid side outlet of the primary heat exchanger 6 is connected in series with the working fluid side inlet of the secondary heat exchanger 7. The working fluid side outlet of the secondary heat exchanger 7 is connected to the inlet pipe of the steam filter.

[0040] The steam outlet of the waste heat recovery steam generator 8 is connected in parallel to the inlet pipe of the variable frequency booster pump 2 via a connecting pipe 81, forming a working fluid confluence structure with the output end of the steam filter. Preferably, a one-way valve 82 is provided on the connecting pipe 81 to prevent the working fluid from flowing back to the storage tank 3.

[0041] Preferably, the output end of the turbine expander 4 is connected to a DC generator set 9, the shaft of the turbine expander 4 is connected to the shaft of the DC generator set 9, and a strong magnetic field protection intelligent control box 10 is also provided on the side of the turbine expander 4. The DC generator set 9 is connected to the strong magnetic field protection intelligent control box 10 through a strong magnetic field protection cable.

[0042] Preferably, a temperature sensor 11 is installed at the bearing of the turbine expander 4, and the temperature sensor 11 is connected to the input terminal of the anti-magnetic fully intelligent control cabinet via a signal line. The bearing temperature is monitored in real time, and when the temperature exceeds a threshold, the control cabinet automatically starts the cooling system or adjusts the unit's operating parameters to prevent the bearing from overheating and being damaged.

[0043] Preferably, a braking mechanism 12 is provided at the rear of the DC generator set 9. A smoke sensor 13 and a temperature flame detector 14 are also provided on the sides of the DC generator set 9 and the turbine expander 4. The smoke sensor 13 and the temperature flame detector 14 are electrically connected to the anti-magnetic fully intelligent control cabinet and linked with the control circuit of the braking mechanism 12. The output end of the control cabinet is connected to the electromagnetic coil of the braking mechanism 12 via a cable, forming a control circuit from the control cabinet to the braking mechanism 12. When the detector detects that the smoke concentration exceeds the threshold or the temperature flame is abnormal, it sends an electrical signal to the control box. After receiving the signal, the PLC controller in the control box immediately outputs a high-level signal to the electromagnetic coil of the braking mechanism 12. The electromagnetic force attracts the armature, causing the friction plate to clamp the brake disc, thereby achieving an emergency stop.

[0044] Preferably, the braking mechanism 12 is an electromagnetic brake, which is installed at the end of the rotating shaft of the DC generator set 9, or on the drive shaft between the turbine expander 4 and the DC generator set 9. The brake disc is ensured to be coaxial with the rotating shaft and fixed by a flange or coupling. In this embodiment, the electromagnetic brake includes an electromagnetic coil, an armature, and a brake disc. When energized, the electromagnetic force attracts the armature, causing the friction pads to brake; when de-energized, the brake is released.

[0045] In this embodiment, a cooling water jacket is provided above the DC generator set 9, and a cooling water receiving pan is provided below the DC generator set 9. The cooling water receiving pan is connected to a cooling water tower through a circulation pipeline and a cooling water circulation pump. A cooling water tower fan is provided on the cooling water tower, and the DC generator set 9 is connected to the power distribution terminal.

[0046] The key design feature of this invention lies in its use of a primary heat exchanger, a secondary heat exchanger, and a waste heat recovery steam generator. The boiler's main exhaust pipe is connected in series with the heat source side of the primary heat exchanger and the heat source side of the secondary heat exchanger. The working fluid side outlet of the primary heat exchanger is connected in series with the working fluid side inlet of the secondary heat exchanger. The working fluid side outlet of the secondary heat exchanger is connected to the inlet pipe of the steam filter. This multi-stage heat exchanger further extracts waste heat from the flue gas before the steam filter, increasing the temperature and pressure of the working fluid steam, allowing the turbine expander to obtain more energy and thus improving its working efficiency. Furthermore, the waste heat recovery steam generator utilizes the waste heat of the low-temperature working fluid in the storage tank to generate steam again, forming a secondary cycle, reducing heat waste, and further improving the system's thermal efficiency.

[0047] The above description is merely a preferred embodiment of the present utility model and does not constitute any limitation on the technical scope of the present utility model. Therefore, any minor modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model shall still fall within the scope of the technical solution of the present utility model.

Claims

1. A turbine flue gas waste heat power generation system with improved thermal efficiency, comprising a boiler, a variable frequency booster pump, a liquid storage tank, and a turbine expander; the boiler is connected to the input end of a steam filter via a flue gas waste heat circulation pipeline; the output end of the steam filter is connected to the input end of the variable frequency booster pump; the output end of the variable frequency booster pump is connected to the input end of the turbine expander; the output end of the turbine expander is connected to the liquid storage tank, and the output end of the liquid storage tank is connected to the flue gas waste heat circulation pipeline to form a loop; characterized in that: The turbine flue gas waste heat power generation system with improved thermal efficiency also includes a primary heat exchanger, a secondary heat exchanger, and a waste heat recovery steam generator. The liquid storage tank is provided with a working fluid reflux port and a low-temperature working fluid outlet. The working fluid reflux port is connected to the working fluid side inlet of the first-stage heat exchanger through a first connecting pipe, and the low-temperature working fluid outlet is connected to the working fluid inlet of the waste heat recovery steam generator through a second connecting pipe. The boiler's main exhaust pipe is connected in series with the heat source side of the primary heat exchanger and the heat source side of the secondary heat exchanger. The working fluid side outlet of the primary heat exchanger is connected in series with the working fluid side inlet of the secondary heat exchanger. The working fluid side outlet of the secondary heat exchanger is connected to the inlet pipe of the steam filter. The steam outlet of the waste heat recovery steam generator is connected in parallel to the inlet pipe of the variable frequency booster pump through a connecting pipe, so that it forms a working fluid manifold structure with the output end of the steam filter.

2. The turbine flue gas waste heat power generation system with improved thermal efficiency according to claim 1, characterized in that: A one-way valve is installed on the connecting pipeline to prevent the working fluid from flowing back into the storage tank.

3. The turbine flue gas waste heat power generation system with improved thermal efficiency according to claim 1, characterized in that: The output end of the turbine expander is connected to a DC generator set, the shaft of the turbine expander is connected to the shaft of the DC generator set, and a fully intelligent control box with strong magnetic field protection is also installed on the side of the turbine expander. The DC generator set is connected to the fully intelligent control box with strong magnetic field protection via a cable with strong magnetic field protection.

4. The turbine flue gas waste heat power generation system with improved thermal efficiency according to claim 3, characterized in that: A temperature sensor is installed at the bearing of the turbine expander, and the temperature sensor is connected to the input terminal of the anti-magnetic fully intelligent control cabinet via a signal line.

5. The turbine flue gas waste heat power generation system with improved thermal efficiency according to claim 3, characterized in that: A braking mechanism is installed at the rear of the DC generator set. A smoke sensor and a temperature flame detector are also installed on the side of the DC generator set and the turbine expander. The smoke sensor and the temperature flame detector are electrically connected to the anti-magnetic fully intelligent control cabinet and are linked to the control circuit of the braking mechanism.

6. The turbine flue gas waste heat power generation system with improved thermal efficiency according to claim 5, characterized in that: The braking mechanism is an electromagnetic brake, which is installed at the end of the rotating shaft of the DC generator set, or on the drive shaft of the turbine expander and the DC generator set.

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