A desulfurization slurry waste heat recovery device

Abstract

The utility model relates to flue gas desulfurization waste heat utilization technical field, concretely relates to a kind of desulfurization slurry waste heat recovery device. Including slurry heat exchanger, the slurry inlet of slurry heat exchanger is connected with the desulfurization slurry outlet of desulfurization tower by pipeline, the slurry outlet of slurry heat exchanger is connected with the desulfurization slurry inlet of desulfurization tower by pipeline;The surface water inlet of slurry heat exchanger is connected with slurry heat exchange total valve by surface water inlet pipe, and the surface water outlet of slurry heat exchanger is connected with slurry heat exchange return water total valve by surface water outlet pipe;Further including plate heat exchanger, the heat medium water inlet of plate heat exchanger is connected with surface water outlet pipe by pipeline, and the heat medium water outlet of plate heat exchanger is connected with surface water inlet pipe by pipeline;The desalted water inlet of plate heat exchanger is connected with desalted water pipeline;The desalted water outlet of plate heat exchanger is connected with steam turbine shaft adding system by pipeline. The utility model technical scheme can be applied to waste heat recovery and utilization field.

Description

Technical Field

[0001] This utility model relates to the field of waste heat utilization technology in flue gas desulfurization, specifically to a waste heat recovery device for desulfurization slurry. Background Technology

[0002] Low-grade waste heat refers to waste heat resources with lower temperatures and energy densities but abundant reserves. These typically originate from industrial processes, coal-fired power plants, boiler flue gas, cooling water, and exhaust gas emission systems. Combined heat and power (CHP) and industrial waste heat have enormous potential; from an economic, energy efficiency, and environmental emission perspective, low-grade waste heat represents a key breakthrough in achieving energy conservation and emission reduction goals.

[0003] In the field of coal-fired power plants and industrial boilers, desulfurization towers are commonly installed at the end of exhaust gas emission systems to control emissions of pollutants such as SO2 and particulate matter. Among them, the limestone-gypsum wet desulfurization process has become the mainstream technology due to its maturity, stability, high desulfurization efficiency, and low operating cost. The core principle of this process is as follows: high-temperature flue gas at 120℃-150℃ enters the desulfurization tower and comes into counter-current contact with desulfurization slurry sprayed from top to bottom. After being washed by the desulfurization slurry, sulfur-containing gases and other pollutants in the flue gas are effectively removed, and the flue gas temperature drops to about 50℃ before being discharged through the chimney. During this process, most of the waste heat in the flue gas is transferred to the desulfurization slurry through heat exchange. How to effectively recover and utilize the waste heat of the desulfurization slurry has become an urgent problem to be solved.

[0004] Currently, the design and application of existing desulfurization slurry waste heat recovery heat exchangers are limited to a single scenario. Their heat exchange function is typically matched only to the heat demand of a specific season and a specific system, that is, providing heating services for a specific working fluid (such as makeup water for the water treatment system) only in a fixed season (such as winter). When the seasons change and the heat demand of the specific system decreases, the slurry waste heat recovery heat exchanger will enter an idle state. This single-scenario design mode leads to two prominent problems: First, the waste heat in the desulfurization slurry cannot be effectively recovered during the non-heat exchanger operating season and can only be directly lost with the desulfurization slurry circulation, resulting in a large amount of energy waste and reducing the overall energy utilization efficiency of the power plant; second, as a dedicated heat exchange device, the slurry waste heat recovery heat exchanger has a short annual operating time and low equipment utilization rate, which not only fails to fully realize the investment benefits of the equipment, but also restricts the further improvement of the power plant's energy cascade utilization level, becoming a technical problem that urgently needs to be solved in the field of waste heat recovery in desulfurization systems. Utility Model Content

[0005] To address the technical problems of insufficient utilization of heat from desulfurization slurry in existing desulfurization towers and low utilization rate of desulfurization slurry heat exchangers, this invention provides a desulfurization slurry waste heat recovery device to solve these problems. This invention, by adding a heat transfer fluid pump and a plate heat exchanger, coupled with dual-condition valve control, achieves dual-condition switching between heating demineralized water in summer and heating surface water in winter, enabling efficient year-round recovery of desulfurization slurry waste heat and improving the energy utilization efficiency and economic benefits of power plants.

[0006] The technical solution of this utility model is as follows: A waste heat recovery device for desulfurization slurry includes a slurry heat exchanger, wherein the slurry inlet of the slurry heat exchanger is connected to the desulfurization slurry outlet of the desulfurization tower via a pipeline, and the slurry outlet of the slurry heat exchanger is connected to the desulfurization slurry inlet of the desulfurization tower via a pipeline. The surface water inlet of the slurry heat exchanger is connected to the slurry heat exchange main valve through the surface water inlet pipe, and the surface water outlet of the slurry heat exchanger is connected to the slurry heat exchange return water main valve through the surface water outlet pipe. It also includes plate heat exchangers, with the heat medium water inlet of the plate heat exchanger connected to the surface water outlet pipe via a pipeline, and the heat medium water outlet of the plate heat exchanger connected to the surface water inlet pipe via a pipeline; the demineralized water inlet of the plate heat exchanger is connected to the demineralized water pipeline; and the demineralized water outlet of the plate heat exchanger is connected to the turbine shaft heating system via a pipeline.

[0007] Furthermore, a slurry vent valve is installed at the top of the slurry heat exchanger, and a slurry drain valve is installed at the bottom of the slurry heat exchanger.

[0008] Furthermore, a surface water inlet valve is installed on the surface water inlet pipe, and a surface water outlet valve is installed on the surface water outlet pipe.

[0009] Furthermore, a water-side vent valve and a water-side drain valve are installed on one side of the slurry heat exchanger.

[0010] Furthermore, a slurry outlet valve is installed on the pipelines connecting the slurry inlet and the desulfurization slurry outlet.

[0011] Furthermore, a slurry inlet valve is installed on the pipeline between the slurry outlet and the desulfurization slurry inlet.

[0012] Furthermore, a heat transfer water inlet valve is installed on the heat transfer water inlet pipe, and a heat transfer water outlet valve is installed on the heat transfer water outlet pipe.

[0013] The working principle of this invention is as follows: High-temperature desulfurization slurry flows out of the desulfurization tower and enters the slurry heat exchanger. A slurry inlet valve is installed on the pipe between the slurry inlet of the slurry heat exchanger and the desulfurization slurry outlet of the desulfurization tower to control the opening and closing of the pipe. The high-temperature desulfurization slurry enters the slurry heat exchanger through the slurry inlet valve. In winter, surface water enters the slurry heat exchanger through the surface water inlet pipe. While heating the surface water, the temperature of the desulfurization slurry itself decreases, and it flows back to the desulfurization tower through the slurry outlet valve. The heated surface water is then transported to the heating demand side. In summer, the heat transfer medium water, driven by the heat transfer medium water pump, enters the slurry heat exchanger to absorb waste heat, and is then transported to the plate heat exchanger to heat the low-pressure demineralized water from the demineralized water pipe. After releasing heat, the heat transfer medium water circulates back to heat the demineralized water and is then transported to the turbine shaft heating system.

[0014] The beneficial effects of this utility model are as follows: (1) The waste heat recovery device for desulfurization slurry provided by this utility model connects the slurry heat exchanger to the desulfurization tower and the plate heat exchanger to the groundwater outlet pipe and the demineralized water pipe. In winter, the groundwater enters the slurry heat exchanger through the groundwater inlet pipe and the slurry heat exchange main valve to absorb heat for heating. In summer, the heat transfer medium water is circulated and the demineralized water is heated by the plate heat exchanger. The temperature of the slurry after heat exchange is controlled, which not only efficiently recovers waste heat, but also ensures the stability of the desulfurization reaction. The slurry heat exchanger is equipped with a slurry exhaust valve to prevent air blockage and an emptying valve for easy maintenance. A water-side drain valve is provided on one side to remove impurities. The groundwater, heat transfer medium water and slurry pipes are all equipped with dedicated valves, which can independently control the flow and switch between winter and summer modes, reduce system failures and improve the flexibility of use.

[0015] (2) The present invention can efficiently recover low-grade waste heat, reduce boiler steam consumption, reduce system operating costs, improve energy recovery and utilization rate, and take into account both environmental benefits and economic value. It has good promotion and application value. Attached Figure Description

[0016] To more clearly illustrate the technical solution of this utility model, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of the desulfurization slurry waste heat recovery device of this utility model.

[0018] In the diagram, 1-slurry heat exchanger, 2-slurry inlet, 3-desulfurization tower, 4-desulfurization slurry outlet, 5-slurry outlet, 6-desulfurization slurry inlet, 7-surface water inlet, 8-surface water inlet pipe, 9-slurry heat exchange main valve, 10-surface water outlet, 11-surface water outlet pipe, 12-slurry heat exchange return water main valve, 13-plate heat exchanger, 14-heat medium water inlet, 15-heat medium water outlet, 16-demineralized water inlet, 17-demineralized water inlet, 18-demineralized water outlet, 19-demineralized water outlet, 10-surface water outlet, 11-surface water outlet pipe, 12-slurry heat exchange return water main valve, 13-plate heat exchanger, 14-heat medium water inlet, 15-heat medium water outlet, 16-demineralized water inlet, 17-demineralized water outlet, 19-demineralized water outlet, 10-surface water outlet, 10-surface water outlet, 11-demineralized water outlet, 12-demineralized water outlet, 13-plate heat exchanger, 14-heat medium water inlet, 15-heat medium water outlet, 16-demineralized water inlet, 17-demineralized water outlet, 19-demineralized water outlet, 10-surface water outlet, 11-demineralized water outlet, 12 ... 18-Brine pipeline, 19-Demineralized water outlet, 20-Steam turbine shaft filling system, 21-Slurry vent valve, 22-Slurry drain valve, 23-Surface water inlet valve, 24-Surface water outlet valve, 25-Water side vent valve, 26-Slurry inlet valve, 27-Slurry outlet valve, 28-Heat medium water pump, 29-Heat medium water inlet pipe, 30-Heat medium water inlet valve, 31-Heat medium water outlet pipe, 32-Heat medium water outlet valve. Detailed Implementation

[0019] To make the objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0020] Example 1 The specific description of the embodiments of this utility model is as follows: A desulfurization slurry waste heat recovery device includes a slurry heat exchanger 1. The slurry inlet 2 of the slurry heat exchanger 1 is connected to the desulfurization slurry outlet 4 of the desulfurization tower 3 via a pipeline, and the slurry outlet 5 of the slurry heat exchanger 1 is connected to the desulfurization slurry inlet 6 of the desulfurization tower via a pipeline. The heat exchange area of ​​the slurry heat exchanger is 600 m². 2The slurry temperature after heat exchange in the slurry heat exchanger is not lower than 41℃; the surface water inlet 7 of the slurry heat exchanger 1 is connected to the slurry heat exchange main valve 9 through the surface water inlet pipe 8, and the surface water outlet 10 of the slurry heat exchanger 1 is connected to the slurry heat exchange return water main valve 12 through the surface water outlet pipe 11; it also includes a plate heat exchanger 13, the heat medium water inlet 14 of the plate heat exchanger 13 is connected to the surface water outlet pipe 11 through a pipe, and the heat medium water outlet 15 of the plate heat exchanger 13 is connected to the surface water inlet pipe 8 through a pipe; the demineralized water inlet 16 of the plate heat exchanger 13 is connected to the demineralized water pipe 17; the demineralized water outlet 18 of the plate heat exchanger 13 is connected to the turbine shaft heating system 19 through a pipe; a slurry exhaust valve 20 is provided at the top of the slurry heat exchanger, and a slurry exhaust valve 20 is provided at the bottom of the slurry heat exchanger. A slurry drain valve 21 is provided; a surface water inlet valve 22 is provided on the surface water inlet pipe 8, and a surface water outlet valve 23 is provided on the surface water outlet pipe; a water-side vent valve 24 and a water-side drain valve 25 are provided on one side of the slurry heat exchanger; a slurry inlet valve 26 is provided on the pipe connecting the slurry inlet 2 of the slurry heat exchanger 1 to the desulfurization slurry outlet 4 of the desulfurization tower; a slurry outlet valve 27 is provided on the pipe connecting the slurry outlet 5 of the slurry heat exchanger 1 to the desulfurization slurry inlet 6 of the desulfurization tower; the heat medium water outlet 15 of the plate heat exchanger 13 is connected to the heat medium water pump 28 through a pipe; a heat medium water inlet valve 30 is provided on the heat medium water inlet pipe 29, and a heat medium water outlet valve 32 is provided on the heat medium water outlet pipe 31; the heat medium water pump has a power of 18.5KW and a head of 28 meters; the heat exchange area of ​​the plate heat exchanger is 180m². 2 The temperature of the demineralized water heated by the plate heat exchanger is not lower than 40°C.

[0021] The working principle of Example 1 is as follows: The high-temperature desulfurization slurry (approximately 51°C) discharged during the operation of desulfurization tower 3 is transported to the connecting pipeline via desulfurization slurry outlet 4. A slurry inlet valve 26 is installed on the pipeline between the slurry inlet 2 of slurry heat exchanger 1 and the desulfurization slurry outlet 4 of desulfurization tower 3 to control the opening and closing of the pipeline. The high-temperature desulfurization slurry enters the slurry heat exchanger 1 with a heat exchange area of ​​600m² through the slurry inlet valve 26 and the pipeline. After the slurry indirectly exchanges heat with the medium on the other side (surface water in winter and hot water in summer) in the internal flow channel to release waste heat, it passes through the slurry... The slurry is delivered to the connecting pipeline via outlet 5. A slurry outlet valve 27 is installed on the pipeline between the slurry outlet 5 of the slurry heat exchanger 1 and the desulfurization slurry inlet 6 of the desulfurization tower 3 to control the opening and closing of the pipeline. The slurry after heat exchange flows back to the desulfurization tower 3 through the slurry outlet valve 27. The temperature of the slurry after heat exchange is strictly controlled to be no lower than 41°C to avoid affecting the desulfurization reaction efficiency. The slurry exhaust valve 20 at the top of the slurry heat exchanger 1 can discharge the air entrained in the slurry to prevent air blockage. The slurry drain valve 21 at the bottom facilitates the emptying of residual slurry during maintenance.

[0022] When surface water needs to be heated in winter, a surface water inlet valve 22 is installed on the surface water inlet pipe 8 to control the opening and closing of the pipe, and a surface water outlet valve 23 is installed on the surface water outlet pipe 11 to control the opening and closing of the pipe. At this time, the slurry heat exchange main valve 9, the slurry heat exchange return water main valve 12, the surface water inlet valve 22, and the surface water outlet valve 23 are opened, and the heat medium water pump 28 and the demineralized water branch valve are closed. The surface water enters the slurry heat exchanger 1 through the surface water inlet pipe 8 and the surface water inlet valve 22. After absorbing the residual heat of the slurry, it is transported to the heating demand end through the surface water outlet pipe 11 and the surface water outlet valve 23. A water-side air vent valve 24 and a water-side drain valve 25 are installed on one side of the slurry heat exchanger 1. The water-side air vent valve 24 can discharge air from the surface water circuit, and the water-side drain valve 25 regularly discharges impurities and scale to ensure heat exchange efficiency.

[0023] When switching to demineralized water heating mode in summer, close the surface water circuit valve, start the heat transfer water pump 28, open the heat transfer water inlet valve 30 on the heat transfer water inlet pipe 29 and the heat transfer water outlet valve 32 on the heat transfer water outlet pipe 31. Driven by the heat transfer water pump 28, the heat transfer water enters the slurry heat exchanger 1, absorbs the residual heat of the slurry, and is then transported through the heat transfer water outlet pipe 31 to the plate heat exchanger 13 with a heat exchange area of ​​180m². The heat transfer water indirectly exchanges heat with the low-pressure demineralized water connected to the demineralized water pipe 17 in the plate heat exchanger 13, raising the temperature of the demineralized water to not less than 40℃, and then is transported through the demineralized water outlet 18 to the turbine shaft heating system 19. The heat-released heat transfer water flows back to the heat transfer water pump 28 through the heat transfer water outlet 15 of the plate heat exchanger 13, forming a closed loop.

[0024] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A desulfurization slurry waste heat recovery device, comprising a slurry heat exchanger (1), characterized in that, The slurry inlet (2) of the slurry heat exchanger (1) is connected to the desulfurization slurry outlet (4) of the desulfurization tower (3) through a pipeline, and the slurry outlet (5) of the slurry heat exchanger (1) is connected to the desulfurization slurry inlet (6) of the desulfurization tower (3) through a pipeline. The surface water inlet (7) of the slurry heat exchanger (1) is connected to the slurry heat exchange main valve (9) through the surface water inlet pipe (8), and the surface water outlet (10) of the slurry heat exchanger (1) is connected to the slurry heat exchange return water main valve (12) through the surface water outlet pipe (11). It also includes a plate heat exchanger (13), the heat medium water inlet (14) of the plate heat exchanger (13) is connected to the surface water outlet pipe (11) through a pipe, the heat medium water outlet (15) of the plate heat exchanger (13) is connected to the surface water inlet pipe (8) through a pipe; the demineralized water inlet (16) of the plate heat exchanger (13) is connected to the demineralized water pipe (17); the demineralized water outlet (18) of the plate heat exchanger (13) is connected to the turbine shaft heating system (19) through a pipe.

2. The desulfurization slurry waste heat recovery device as described in claim 1, characterized in that, The slurry heat exchanger (1) is provided with a slurry exhaust valve (20) at the top and a slurry drain valve (21) at the bottom.

3. The desulfurization slurry waste heat recovery device as described in claim 1, characterized in that, A surface water inlet valve (22) is installed on the surface water inlet pipe (8), and a surface water outlet valve (23) is installed on the surface water outlet pipe (11).

4. The desulfurization slurry waste heat recovery device as described in claim 2, characterized in that, A water-side vent valve (24) and a water-side drain valve (25) are provided on one side of the slurry heat exchanger.

5. The desulfurization slurry waste heat recovery device as described in claim 1, characterized in that, A slurry inlet valve (26) is installed on the pipeline between the slurry inlet (2) and the desulfurization slurry outlet (4).

6. The desulfurization slurry waste heat recovery device as described in claim 1, characterized in that, A slurry outlet valve (27) is installed on the pipeline between the slurry outlet (5) and the desulfurization slurry inlet (6).

7. The desulfurization slurry waste heat recovery device as described in claim 1, characterized in that, The heat medium water outlet (15) of the plate heat exchanger is connected to the heat medium water pump (28) via a pipe.

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