Wet desulphurization process surface type water-saving flue gas waste heat power generation system

Abstract

The utility model discloses a wet desulfurization process surface type water-saving flue gas waste heat power generation system, which belongs to the technical field of energy conservation and environmental protection and comprises a desulfurization tower communicated with an inlet flue and an outlet flue. The raw flue gas heat removal system is arranged in the inlet flue and is used for obtaining heat of the high-temperature raw flue gas in the inlet flue and reducing the temperature of the high-temperature raw flue gas entering the desulfurization tower; the heat obtained from the raw flue gas heat extraction system is used for generating power for the screw machine power generation system; the flue gas condensation system comprises a low-temperature section heat exchanger fixedly connected to the outlet flue, the outlet flue is communicated with a flue gas channel in the low-temperature section heat exchanger, and the bottom end of the flue gas channel in the low-temperature section heat exchanger is communicated with a condensate water storage tank. The flue gas waste heat can be utilized for power generation, and flue gas heat energy is converted into electric energy to generate economic benefits; meanwhile, moisture in the flue gas at the outlet of the desulfurizing tower can be extracted, the problem of excessive water consumption of enterprises is solved, and the colored smoke plume phenomenon is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of energy conservation and environmental protection, in particular to a surface type water-saving flue gas waste heat power generation system of a wet desulfurization process. Background Art

[0002] Flue gas desulfurization systems for thermal power generating units mostly use wet desulfurization. During the wet desulfurization process, during the countercurrent flow of circulating slurry and high-temperature raw flue gas, chemical reactions remove sulfur oxides in the flue gas. During the reaction, the heat in the raw flue gas is transferred to the slurry. After the slurry absorbs heat, part of the water evaporates and is carried away by the flue gas, eventually forming saturated wet flue gas. A large amount of water is discharged into the atmosphere along with the flue gas, causing a waste of water while generating visual pollution such as colored plumes. In addition, the discharged saturated wet flue gas contains a certain amount of heat, which is not fully utilized.

[0003] Therefore, a surface type water-saving flue gas waste heat power generation system with wet desulfurization process is proposed. Utility Model Content

[0004] The utility model aims to provide a surface type water-saving flue gas waste heat power generation system for a wet desulfurization process, aiming to solve or improve at least one of the above-mentioned technical problems.

[0005] To achieve the above purpose, the utility model provides the following solution: The utility model provides a surface water-saving flue gas waste heat power generation system for a wet desulfurization process, comprising:

[0006] A desulfurization tower, wherein an inlet flue and an outlet flue are fixedly connected and communicated with the desulfurization tower;

[0007] A raw flue gas heat extraction system is arranged in the inlet flue, and is used to obtain heat from the high-temperature raw flue gas in the inlet flue, thereby reducing the temperature of the high-temperature raw flue gas entering the desulfurization tower;

[0008] A screw machine power generation system, wherein the heat obtained from the original flue gas heat extraction system is used to generate electricity for the screw machine power generation system;

[0009] The flue gas condensation system comprises a low temperature section heat exchanger fixedly connected to the outlet flue, the outlet flue is connected to the flue gas channel in the low temperature section heat exchanger, and the bottom end of the flue gas channel in the low temperature section heat exchanger is connected to a condensed water storage tank.

[0010] Preferably, the water inlet end of the low-temperature section heat exchanger is connected to the raw water tank, and the water outlet end is connected to the water inlet end of the desalted water preparation equipment. A raw water booster pump is connected between the water inlet end of the low-temperature section heat exchanger and the raw water tank, and the water outlet end of the condensed water storage tank is connected to the water inlet end of the raw water tank.

[0011] Preferably, the condensed water storage tank is provided with a condensed water quality regulating system, and a condensed water booster pump is connected between the water outlet end of the condensed water storage tank and the water inlet end of the raw water tank.

[0012] Preferably, the original flue gas heat extraction system includes a high-temperature section heat exchanger and a hot-end plate heat exchanger, the high-temperature section heat exchanger is fixedly connected to the inlet flue, and the flue gas channel in the high-temperature section heat exchanger is connected to the inlet flue; the first water inlet of the hot-end plate heat exchanger is connected to the water outlet of the high-temperature section heat exchanger, and the first water outlet of the hot-end plate heat exchanger is connected to the water inlet of the high-temperature section heat exchanger, and a heat medium desalted water circulation pump is connected between the first water outlet of the hot-end plate heat exchanger and the water inlet of the high-temperature section heat exchanger.

[0013] Preferably, the screw machine power generation system includes a screw machine, a reducer and a generator, the output end of the screw machine is fixedly connected to the reducer, the output end of the reducer is fixedly connected to the generator, the second water inlet of the hot end plate heat exchanger is connected to the air outlet of the screw machine, and the second water outlet of the hot end plate heat exchanger is connected to the air inlet of the screw machine.

[0014] Preferably, it also includes a cold-end plate heat exchanger, the air outlet end of the screw machine is connected to the first water inlet of the cold-end plate heat exchanger, and the second water inlet of the hot-end plate heat exchanger is connected to the first water outlet of the cold-end plate heat exchanger; the output end of the desalted water preparation equipment is connected to the first water inlet of the cold-end plate heat exchanger, and the first water outlet of the cold-end plate heat exchanger is connected to the thermal system.

[0015] Preferably, a desalted water booster pump is connected between the output end of the desalted water preparation equipment and the first water inlet of the cold-end plate heat exchanger.

[0016] The utility model discloses the following technical effects: before the high-temperature raw flue gas enters the desulfurization tower, it first passes through the raw flue gas heat extraction system for heat exchange, which can extract part of the heat in the flue gas for power generation of the screw machine power generation system on the one hand, and reduce the temperature and speed of the flue gas entering the desulfurization tower on the other hand, thereby reducing the amount of water lost by evaporation in the desulfurization tower during the wet desulfurization process; the saturated wet flue gas generated after desulfurization enters the outlet flue, and the cold source water in the low-temperature section heat exchanger exchanges heat with the saturated wet flue gas in the outlet flue, and the temperature of the saturated wet flue gas is reduced, so that the water vapor therein condenses to form condensed water and enters the condensed water storage box for collection, thereby reducing the water content in the discharged flue gas, reducing the waste of water, and reducing the colored plume phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0018] Figure 1 It is a structural schematic diagram of the utility model.

[0019] In the figure: 1-1, raw water tank; 1-2, raw water booster pump; 1-3, low-temperature raw water; 1-4, high-temperature raw water; 1-5, desalted water preparation equipment; 1-6, desalted water booster pump; 1-7, cold end plate heat exchanger; 1-8, high-temperature desalted water; 1-9, low-temperature section heat exchanger; 1-10, flue gas condensate; 1-11, condensate storage tank; 1-12, condensate booster pump; 1-13, raw water; 1-14, condensate water quality adjustment system; 1-15, high temperature Saturated clean flue gas; 1-16, low-temperature flue gas; 2-1, high-temperature section heat exchanger; 2-2, heat medium desalted water circulation pump; 2-3, low-temperature heat medium desalted water; 2-4, high-temperature heat medium desalted water; 2-5, hot end plate heat exchanger; 2-6, high-temperature raw flue gas; 2-7, low-temperature raw flue gas; 3-1, high-temperature working fluid steam; 3-2, screw machine; 3-3, reducer; 3-4, generator; 3-5, medium-temperature working fluid exhaust steam; 3-6, low-temperature working fluid; 4, desulfurization tower; 5, chimney. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0021] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0022] Reference Figure 1 The utility model provides a surface water-saving flue gas waste heat power generation system for wet desulfurization process, comprising:

[0023] A desulfurization tower 4, to which an inlet flue and an outlet flue are fixedly connected and communicated, and the outlet flue is communicated with a chimney 5, through which the final flue gas is discharged;

[0024] The raw flue gas heat extraction system is arranged in the inlet flue and is used to obtain the heat of the high-temperature raw flue gas in the inlet flue, thereby reducing the temperature of the high-temperature raw flue gas entering the desulfurization tower 4;

[0025] The screw compressor power generation system uses the heat obtained from the original flue gas heat extraction system to generate electricity for the screw compressor power generation system;

[0026] The flue gas condensation system includes a low-temperature section heat exchanger 1-9 fixedly connected to the outlet flue, the outlet flue is connected to the flue gas channel in the low-temperature section heat exchanger 1-9, and the bottom end of the flue gas channel in the low-temperature section heat exchanger 1-9 is connected to a condensed water storage tank 1-11;

[0027] The low-temperature section heat exchanger 1-9 is a fluoroplastic heat exchanger. The high-temperature saturated clean flue gas 1-15 generated after desulfurization enters the flue gas channel in the low-temperature section heat exchanger 1-9, and exchanges heat with the cold water in the low-temperature section heat exchanger 1-9. The water vapor in the high-temperature saturated clean flue gas 1-15 will condense into droplets, which will continue to gather on the surface of the low-temperature section heat exchanger 1-9 and flow into the water collection tank at the bottom due to gravity. They will then flow through pipes to the condensate storage tank 1-11 for collection, and the low-temperature flue gas 1-16 will be output from the low-temperature section heat exchanger 1-9. The low-temperature flue gas 1-16 enters the chimney 5 for discharge, thereby reducing the water content in the discharged flue gas, reducing water waste, and reducing the colored plume phenomenon.

[0028] Further optimize the scheme, the water inlet end of the low temperature section heat exchanger 1-9 is connected to the raw water tank 1-1, and the water outlet end is connected to the water inlet end of the desalted water preparation equipment 1-5, a raw water booster pump 1-2 is connected between the water inlet end of the low temperature section heat exchanger 1-9 and the raw water tank 1-1, and the water outlet end of the condensed water storage tank 1-11 is connected to the water inlet end of the raw water tank 1-1;

[0029] The condensate storage tank 1-11 is provided with a condensate water quality regulating system 1-14, and a condensate booster pump 1-12 is connected between the water outlet of the condensate storage tank 1-11 and the water inlet of the raw water tank 1-1;

[0030] The raw water tank 1-1 is connected to the external raw water 1-13 as a water supplement. The condensed water collected in the condensed water storage tank 1-11 is processed by the condensed water quality adjustment system 1-14, and then enters the raw water tank 1-1 through the condensed water booster pump 1-12 for use, thereby reducing the usage of the raw water 1-13 and reducing the water consumption in the enterprise operation process; the low-temperature raw water 1-3 in the raw water tank 1-1 is pumped into the low-temperature section heat exchanger 1-9 through the raw water booster pump 1-2 for heat exchange, and the low-temperature section heat exchanger 1-9 outputs high-temperature raw water 1-4 as the water source for the desalted water preparation equipment 1-5. Since the desalted water preparation equipment 1-5 usually needs to heat the external water source to about 25° before it can be used, using the high-temperature raw water 1-4 as the water source for the desalted water preparation equipment 1-5 can reduce the amount of heating and improve the energy saving effect.

[0031] Further optimization scheme, the original flue gas heat extraction system includes a high-temperature section heat exchanger 2-1 and a hot end plate heat exchanger 2-5, the high-temperature section heat exchanger 2-1 is fixedly connected to the inlet flue, and the flue gas channel in the high-temperature section heat exchanger 2-1 is connected to the inlet flue; the first water inlet of the hot end plate heat exchanger 2-5 is connected to the water outlet of the high-temperature section heat exchanger 2-1, the first water outlet of the hot end plate heat exchanger 2-5 is connected to the water inlet of the high-temperature section heat exchanger 2-1, and a heat medium desalted water circulation pump 2-2 is connected between the first water outlet of the hot end plate heat exchanger 2-5 and the water inlet of the high-temperature section heat exchanger 2-1;

[0032] The high temperature section heat exchanger 2-1 is a fluoroplastic heat exchanger.

[0033] To further optimize the solution, the screw machine power generation system includes a screw machine 3-2, a reducer 3-3 and a generator 3-4, the output end of the screw machine 3-2 is fixedly connected to the reducer 3-3, the output end of the reducer 3-3 is fixedly connected to the generator 3-4, the second water inlet of the hot end plate heat exchanger 2-5 is connected to the air outlet of the screw machine 3-2, and the second water outlet of the hot end plate heat exchanger 2-5 is connected to the air inlet of the screw machine 3-2.

[0034] A further optimization scheme also includes a cold-end plate heat exchanger 1-7, the air outlet end of the screw machine 3-2 is connected to the first water inlet of the cold-end plate heat exchanger 1-7, the second water inlet of the hot-end plate heat exchanger 2-5 is connected to the first water outlet of the cold-end plate heat exchanger 1-7; the output end of the desalted water preparation equipment 1-5 is connected to the first water inlet of the cold-end plate heat exchanger 1-7, and the first water outlet of the cold-end plate heat exchanger 1-7 is connected to the thermal system.

[0035] In a further optimized solution, a desalted water booster pump 1-6 is connected between the output end of the desalted water preparation device 1-5 and the first water inlet of the cold end plate heat exchanger 1-7.

[0036] When the utility model is in use, the high-temperature section heat exchanger 2-1 is arranged in the inlet channel of the desulfurization tower 4, and the low-temperature heat medium desalted water 2-3 inside the high-temperature section heat exchanger 2-1 is used to cool the high-temperature original flue gas 2-6 at the inlet of the desulfurization tower 4; the low-temperature heat medium desalted water 2-3 enters the high-temperature section heat exchanger 2-1 under the drive of the heat medium desalted water circulation pump 2-2 to heat up, and the heated high-temperature heat medium desalted water 2-4 enters the hot end plate heat exchanger 2-5 to release heat. This process The heat of flue gas is converted to the working medium through reciprocating cycles; the low-temperature working medium 3-6 is heated by heat exchange with the high-temperature heat medium desalted water 2-4 to become high-temperature working medium steam 3-1, and the high-temperature working medium steam 3-1 enters the screw machine 3-2 for work, and drives the generator 3-4 to generate electricity through the reducer 3-3. The medium-temperature working medium exhaust steam 3-5 after work enters the cold-end plate heat exchanger 1-7 for heat exchange with the normal-temperature desalted water to obtain the low-temperature working medium 3-6. This process is repeated in a cycle to convert the chemical energy of the working medium into electrical energy;

[0037] After the high-temperature raw flue gas 2-6 is cooled, the low-temperature raw flue gas 2-7 enters the desulfurization tower 4 for wet desulfurization. The high-temperature saturated clean flue gas 1-15 after desulfurization is cooled by the low-temperature section heat exchanger 1-9 to generate low-temperature flue gas 1-16, which enters the chimney 5 and is discharged into the atmosphere; during the cooling process of the high-temperature saturated clean flue gas 1-15, the water vapor in the high-temperature saturated clean flue gas 1-15 will condense into droplets, which will continuously gather on the surface of the heat exchange tubes of the low-temperature section heat exchanger 1-9, and flow into the water collection tank at the bottom along the heat exchange tubes due to gravity. The flue gas condensate 1-10 in the water collection tank will then flow through the pipeline to the condensate storage tank 1-11. The condensate in the condensate storage tank 1-11 will be treated by the condensate water quality regulating system 1-14, and then pumped into the raw water tank 1-1 through the condensate booster pump 1-12 as water supplement, and reused, thereby realizing "zero water consumption desulfurization";

[0038] The high-temperature raw water 1-4 after heating output by the low-temperature section heat exchanger 1-9 enters the workshop of the desalted water preparation equipment 1-5 to prepare desalted water. The prepared desalted water can continue to exchange heat with the medium-temperature working fluid exhaust steam 3-5 after power generation through the cold end plate heat exchanger 1-7, and the medium-temperature working fluid exhaust steam 3-5 is cooled to become liquid low-temperature working fluid 3-6. At the same time, the temperature of the desalted water is increased to generate high-temperature desalted water 1-8 for use in subsequent thermal systems.

[0039] Taking a 1000MW unit as an example, according to the design requirements, the high-temperature saturated clean flue gas 1-15 starts to cool down from 50℃, and after cooling, the low-temperature flue gas 1-16 is about 45℃; the temperature of the low-temperature raw water 1-3 is about 5℃, and the high-temperature raw water 1-4 is about 25℃ after heat exchange; the raw water side is heated up, and the flue gas temperature is accompanied by condensed water. It is estimated that 90 tons of flue gas condensed water 1-10 will be generated per hour, and the flue gas condensed water 1-10 will be discharged to the condensed water storage tank 1-11. After the PH value is adjusted by the condensed water quality adjustment system 1-14, it is discharged into the raw water tank 1-1 under the drive of the condensed water booster pump 1-12, so that the condensed water recovery process is realized, and the water collection capacity is about 90t / h;

[0040] After heat exchange, the high-temperature raw water 1-4 is about 25°C, and enters the desalted water preparation equipment 1-5 to produce normal-temperature desalted water. The desalted water enters the cold-end plate heat exchanger 1-7 driven by the desalted water booster pump 1-6 to exchange heat with the medium-temperature working fluid exhaust steam 3-5 after processing. The medium-temperature working fluid exhaust steam 3-5 is reduced from 45°C to 30°C of the low-temperature working fluid 3-6, and the normal-temperature desalted water is heated to about 40°C high-temperature desalted water 1-8 to enter the subsequent process;

[0041] The high-temperature raw flue gas 2-6 starts to cool down from 140°C, and after cooling, the low-temperature raw flue gas 2-7 is about 110°C. The low-temperature heat medium desalted water 2-3 enters the high-temperature section heat exchanger 2-1 driven by the heat medium desalted water circulation pump 2-2 to increase the temperature. The heated high-temperature heat medium desalted water 2-4 enters the hot end plate heat exchanger 2-5 to release heat. This process is repeated to realize the conversion of flue gas heat to the working fluid side.

[0042] The low-temperature working fluid 3-6 is heated by heat exchange with the high-temperature heat medium desalted water 2-4 to become high-temperature working fluid steam 3-1. The high-temperature working fluid steam 3-1 enters the screw machine 3-2 for work, and drives the generator 3-4 to generate electricity through the reducer 3-3. The medium-temperature working fluid exhaust steam 3-5 after work enters the cold-end plate heat exchanger 1-7 for heat exchange with the normal-temperature desalted water to obtain the low-temperature working fluid 3-6. This process is repeated to realize the conversion of the chemical energy of the working fluid into electrical energy.

[0043] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0044] The embodiments described above are only descriptions of the preferred methods of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A surface type water-saving flue gas waste heat power generation system using a wet desulfurization process, characterized in that: include: A desulfurization tower (4), wherein an inlet flue and an outlet flue are fixedly connected and communicated with the desulfurization tower (4); A raw flue gas heat extraction system, arranged in the inlet flue, for obtaining heat from the high-temperature raw flue gas in the inlet flue, thereby reducing the temperature of the high-temperature raw flue gas entering the desulfurization tower (4); A screw machine power generation system, wherein the heat obtained from the original flue gas heat extraction system is used to generate electricity for the screw machine power generation system; The flue gas condensation system comprises a low-temperature section heat exchanger (1-9) fixedly connected to the outlet flue, the outlet flue is connected to the flue gas channel in the low-temperature section heat exchanger (1-9), and the bottom end of the flue gas channel in the low-temperature section heat exchanger (1-9) is connected to a condensate storage tank (1-11).

2. The surface type water-saving flue gas waste heat power generation system of wet desulfurization process according to claim 1 is characterized by: The water inlet end of the low-temperature section heat exchanger (1-9) is connected to the raw water tank (1-1), and the water outlet end is connected to the water inlet end of the desalted water preparation equipment (1-5). A raw water booster pump (1-2) is connected between the water inlet end of the low-temperature section heat exchanger (1-9) and the raw water tank (1-1), and the water outlet end of the condensed water storage tank (1-11) is connected to the water inlet end of the raw water tank (1-1).

3. The surface type water-saving flue gas waste heat power generation system of wet desulfurization process according to claim 2 is characterized by: The condensed water storage tank (1-11) is provided with a condensed water quality regulating system (1-14), and a condensed water booster pump (1-12) is connected between the water outlet of the condensed water storage tank (1-11) and the water inlet of the raw water tank (1-1).

4. The surface type water-saving flue gas waste heat power generation system of wet desulfurization process according to claim 2 is characterized by: The original flue gas heat extraction system comprises a high-temperature section heat exchanger (2-1) and a hot end plate heat exchanger (2-5); the high-temperature section heat exchanger (2-1) is fixedly connected to the inlet flue, and the flue gas channel in the high-temperature section heat exchanger (2-1) is connected to the inlet flue; the first water inlet of the hot end plate heat exchanger (2-5) is connected to the water outlet of the high-temperature section heat exchanger (2-1), the first water outlet of the hot end plate heat exchanger (2-5) is connected to the water inlet of the high-temperature section heat exchanger (2-1), and a heat medium desalted water circulation pump (2-2) is connected between the first water outlet of the hot end plate heat exchanger (2-5) and the water inlet of the high-temperature section heat exchanger (2-1).

5. The surface type water-saving flue gas waste heat power generation system of wet desulfurization process according to claim 4 is characterized in that: The screw machine power generation system comprises a screw machine (3-2), a reducer (3-3) and a generator (3-4); the output end of the screw machine (3-2) is fixedly connected to the reducer (3-3), the output end of the reducer (3-3) is fixedly connected to the generator (3-4), the second water inlet of the hot end plate heat exchanger (2-5) is connected to the air outlet of the screw machine (3-2), and the second water outlet of the hot end plate heat exchanger (2-5) is connected to the air inlet of the screw machine (3-2).

6. The surface type water-saving flue gas waste heat power generation system of wet desulfurization process according to claim 5 is characterized by: It also includes a cold-end plate heat exchanger (1-7), the air outlet end of the screw machine (3-2) is connected to the first water inlet of the cold-end plate heat exchanger (1-7), and the second water inlet of the hot-end plate heat exchanger (2-5) is connected to the first water outlet of the cold-end plate heat exchanger (1-7); the output end of the desalted water preparation equipment (1-5) is connected to the first water inlet of the cold-end plate heat exchanger (1-7), and the first water outlet of the cold-end plate heat exchanger (1-7) is connected to the thermal system.

7. The surface type water-saving flue gas waste heat power generation system of wet desulfurization process according to claim 6 is characterized by: A desalted water booster pump (1-6) is connected between the output end of the desalted water preparation device (1-5) and the first water inlet of the cold end plate heat exchanger (1-7).

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